WorldWideScience

Sample records for attitude flight dynamics

  1. Magnetospheric Multiscale Mission Attitude Dynamics: Observations from Flight Data

    Science.gov (United States)

    Williams, Trevor; Shulman, Seth; Sedlak, Joseph; Ottenstein, Neil; Lounsbury, Brian

    2016-01-01

    Extensive flight data is being collected throughout the MMS mission that includes quantities that are of interest for attitude dynamics studies such as spin rate, spin axis orientation nutation rate, etc. One example of such data is the long-term evolution of the spin rates of the four spacecraft. Spikes in these rates are observed that are separated by the MMS orbital period (just under 24 hr) and occur around perigee due to gravity-gradient torque. Periodic discontinuities in spin rate are caused by the controller resetting the spin rate approximately to the nominal 3.1 RPM value at the time of each maneuver. In between, a slow decay in spin rate can be seen to occur. The paper will discuss various disturbance torque mechanisms that could potentially be responsible for this behavior: these include magnetic hysteresis, eddy currents, solar radiation pressure, and a possible interaction between gravity-gradient and wire boom flexibility effects. One additional disturbance mechanism is produced by the Active Spacecraft Potential Control (ASPOC) devices: these emit positive indium ions to keep the MMS spacecraft electrically neutral, so as not to corrupt the electric field observations that are made by some of the on-board instruments. The spin rate decays that could be produced by these various mechanisms will be quantified in the paper, and their signatures described. Comparing these with the observations from flight data then allow the most likely candidate to be determined.

  2. The Global Positioning System (GPS) and attitude determination: Applications and activities in the Flight Dynamics Division

    Science.gov (United States)

    Ketchum, Eleanor; Garrick, Joe

    1995-01-01

    The application of GPS to spacecraft attitude determination is a new and growing field. Although the theoretical literature is extensive, space flight testing is currently sparse and inadequate. As an operations organization, the Flight Dynamics Division (FDD) has the responsibility to investigate this new technology, and determine how best to implement the innovation to provide adequate support for future missions. This paper presents some of the current efforts within FDD with regard to GPS attitude determination. This effort specifically addresses institutional capabilities to accommodate a new type of sensor, critically evaluating the literature for recent advancements, and in examining some available -albeit crude- flight data.

  3. Flight Dynamics Analysis Branch 2005 Technical Highlights

    Science.gov (United States)

    2005-01-01

    This report summarizes the major activities and accomplishments carried out by the Flight Dynamics Analysis Branch (FDAB), Code 595, in support of flight projects and technology development initiatives in Fiscal Year (FY) 2005. The report is intended to serve as a summary of the type of support carried out by the FDAB, as well as a concise reference of key accomplishments and mission experience derived from the various mission support roles. The primary focus of the FDAB is to provide expertise in the disciplines of flight dynamics including spacecraft navigation (autonomous and ground based); spacecraft trajectory design and maneuver planning; attitude analysis; attitude determination and sensor calibration; and attitude control subsystem (ACS) analysis and design. The FDAB currently provides support for missions and technology development projects involving NASA, other government agencies, academia, and private industry.

  4. Solar array flight dynamic experiment

    Science.gov (United States)

    Schock, Richard W.

    1987-01-01

    The purpose of the Solar Array Flight Dynamic Experiment (SAFDE) is to demonstrate the feasibility of on-orbit measurement and ground processing of large space structures' dynamic characteristics. Test definition or verification provides the dynamic characteristic accuracy required for control systems use. An illumination/measurement system was developed to fly on space shuttle flight STS-41D. The system was designed to dynamically evaluate a large solar array called the Solar Array Flight Experiment (SAFE) that had been scheduled for this flight. The SAFDE system consisted of a set of laser diode illuminators, retroreflective targets, an intelligent star tracker receiver and the associated equipment to power, condition, and record the results. In six tests on STS-41D, data was successfully acquired from 18 retroreflector targets and ground processed, post flight, to define the solar array's dynamic characteristic. The flight experiment proved the viability of on-orbit test definition of large space structures dynamic characteristics. Future large space structures controllability should be greatly enhanced by this capability.

  5. The dynamics of parabolic flight: Flight characteristics and passenger percepts

    Science.gov (United States)

    Karmali, Faisal; Shelhamer, Mark

    2008-09-01

    Flying a parabolic trajectory in an aircraft is one of the few ways to create freefall on Earth, which is important for astronaut training and scientific research. Here we review the physics underlying parabolic flight, explain the resulting flight dynamics, and describe several counterintuitive findings, which we corroborate using experimental data. Typically, the aircraft flies parabolic arcs that produce approximately 25 s of freefall (0 g) followed by 40 s of enhanced force (1.8 g), repeated 30-60 times. Although passengers perceive gravity to be zero, in actuality acceleration, and not gravity, has changed, and thus we caution against the terms "microgravity" and "zero gravity." Despite the aircraft trajectory including large (45°) pitch-up and pitch-down attitudes, the occupants experience a net force perpendicular to the floor of the aircraft. This is because the aircraft generates appropriate lift and thrust to produce the desired vertical and longitudinal accelerations, respectively, although we measured moderate (0.2 g) aft-ward accelerations during certain parts of these trajectories. Aircraft pitch rotation (average 3°/s) is barely detectable by the vestibular system, but could influence some physics experiments. Investigators should consider such details in the planning, analysis, and interpretation of parabolic-flight experiments.

  6. The accuracy of dynamic attitude propagation

    Science.gov (United States)

    Harvie, E.; Chu, D.; Woodard, M.

    1990-01-01

    Propagating attitude by integrating Euler's equation for rigid body motion has long been suggested for the Earth Radiation Budget Satellite (ERBS) but until now has not been implemented. Because of limited Sun visibility, propagation is necessary for yaw determination. With the deterioration of the gyros, dynamic propagation has become more attractive. Angular rates are derived from integrating Euler's equation with a stepsize of 1 second, using torques computed from telemetered control system data. The environmental torque model was quite basic. It included gravity gradient and unshadowed aerodynamic torques. Knowledge of control torques is critical to the accuracy of dynamic modeling. Due to their coarseness and sparsity, control actuator telemetry were smoothed before integration. The dynamic model was incorporated into existing ERBS attitude determination software. Modeled rates were then used for attitude propagation in the standard ERBS fine-attitude algorithm. In spite of the simplicity of the approach, the dynamically propagated attitude matched the attitude propagated with good gyros well for roll and yaw but diverged up to 3 degrees for pitch because of the very low resolution in pitch momentum wheel telemetry. When control anomalies significantly perturb the nominal attitude, the effect of telemetry granularity is reduced and the dynamically propagated attitudes are accurate on all three axes.

  7. Automated Flight Routing Using Stochastic Dynamic Programming

    Science.gov (United States)

    Ng, Hok K.; Morando, Alex; Grabbe, Shon

    2010-01-01

    Airspace capacity reduction due to convective weather impedes air traffic flows and causes traffic congestion. This study presents an algorithm that reroutes flights in the presence of winds, enroute convective weather, and congested airspace based on stochastic dynamic programming. A stochastic disturbance model incorporates into the reroute design process the capacity uncertainty. A trajectory-based airspace demand model is employed for calculating current and future airspace demand. The optimal routes minimize the total expected traveling time, weather incursion, and induced congestion costs. They are compared to weather-avoidance routes calculated using deterministic dynamic programming. The stochastic reroutes have smaller deviation probability than the deterministic counterpart when both reroutes have similar total flight distance. The stochastic rerouting algorithm takes into account all convective weather fields with all severity levels while the deterministic algorithm only accounts for convective weather systems exceeding a specified level of severity. When the stochastic reroutes are compared to the actual flight routes, they have similar total flight time, and both have about 1% of travel time crossing congested enroute sectors on average. The actual flight routes induce slightly less traffic congestion than the stochastic reroutes but intercept more severe convective weather.

  8. Satellite recovery - Attitude dynamics of the targets

    Science.gov (United States)

    Cochran, J. E., Jr.; Lahr, B. S.

    1986-01-01

    The problems of categorizing and modeling the attitude dynamics of uncontrolled artificial earth satellites which may be targets in recovery attempts are addressed. Methods of classification presented are based on satellite rotational kinetic energy, rotational angular momentum and orbit and on the type of control present prior to the benign failure of the control system. The use of approximate analytical solutions and 'exact' numerical solutions to the equations governing satellite attitude motions to predict uncontrolled attitude motion is considered. Analytical and numerical results are presented for the evolution of satellite attitude motions after active control termination.

  9. Automation Framework for Flight Dynamics Products Generation

    Science.gov (United States)

    Wiegand, Robert E.; Esposito, Timothy C.; Watson, John S.; Jun, Linda; Shoan, Wendy; Matusow, Carla

    2010-01-01

    XFDS provides an easily adaptable automation platform. To date it has been used to support flight dynamics operations. It coordinates the execution of other applications such as Satellite TookKit, FreeFlyer, MATLAB, and Perl code. It provides a mechanism for passing messages among a collection of XFDS processes, and allows sending and receiving of GMSEC messages. A unified and consistent graphical user interface (GUI) is used for the various tools. Its automation configuration is stored in text files, and can be edited either directly or using the GUI.

  10. The effects of Crew Resource Management (CRM) training on flight attendants' safety attitudes.

    Science.gov (United States)

    Ford, Jane; Henderson, Robert; O'Hare, David

    2014-02-01

    A number of well-known incidents and accidents had led the aviation industry to introduce Crew Resource Management (CRM) training designed specifically for flight attendants, and joint (pilot and flight attendant) CRM training as a way to improve teamwork and communication. The development of these new CRM training programs during the 1990s highlighted the growing need for programs to be evaluated using research tools that had been validated for the flight attendant population. The FSAQ (Flight Safety Attitudes Questionnaire-Flight Attendants) was designed specifically to obtain safety attitude data from flight attendants working for an Asia-Pacific airline. Flight attendants volunteered to participate in a study before receiving CRM training (N=563) and again (N=526) after CRM training. Almost half (13) of the items from the 36-item FSAQ showed highly significant changes following CRM training. Years of experience, crew position, seniority, leadership roles, flight attendant crew size, and length of route flown were all predictive of safety attitudes. CRM training for flight attendants is a valuable tool for increasing positive teamwork behaviors between the flight attendant and pilot sub-groups. Joint training sessions, where flight attendants and pilots work together to find solutions to in-flight emergency scenarios, provide a particularly useful strategy in breaking down communication barriers between the two sub-groups. Copyright © 2013 National Safety Council and Elsevier Ltd. All rights reserved.

  11. Production and quality assurance automation in the Goddard Space Flight Center Flight Dynamics Facility

    Science.gov (United States)

    Chapman, K. B.; Cox, C. M.; Thomas, C. W.; Cuevas, O. O.; Beckman, R. M.

    1994-01-01

    The Flight Dynamics Facility (FDF) at the NASA Goddard Space Flight Center (GSFC) generates numerous products for NASA-supported spacecraft, including the Tracking and Data Relay Satellites (TDRS's), the Hubble Space Telescope (HST), the Extreme Ultraviolet Explorer (EUVE), and the space shuttle. These products include orbit determination data, acquisition data, event scheduling data, and attitude data. In most cases, product generation involves repetitive execution of many programs. The increasing number of missions supported by the FDF has necessitated the use of automated systems to schedule, execute, and quality assure these products. This automation allows the delivery of accurate products in a timely and cost-efficient manner. To be effective, these systems must automate as many repetitive operations as possible and must be flexible enough to meet changing support requirements. The FDF Orbit Determination Task (ODT) has implemented several systems that automate product generation and quality assurance (QA). These systems include the Orbit Production Automation System (OPAS), the New Enhanced Operations Log (NEOLOG), and the Quality Assurance Automation Software (QA Tool). Implementation of these systems has resulted in a significant reduction in required manpower, elimination of shift work and most weekend support, and improved support quality, while incurring minimal development cost. This paper will present an overview of the concepts used and experiences gained from the implementation of these automation systems.

  12. Flight Dynamics Analysis for Leonardo-BRDF

    Science.gov (United States)

    Hughes, Steven P.; Mailhe, Laurie; Bauer, Frank H. (Technical Monitor)

    2000-01-01

    Leonardo-BRDF (Bidirectional Reflectance Distribution Function) is a new NASA mission concept proposed to allow the investigation of radiative transfer and its effect on the Earth's climate and atmospheric phenomenon. Enabled by the recent developments in small-satellite and formation flying technology, the mission is envisioned to be composed of an array of spacecraft in carefully designed orbits. The different perspectives provided by a distributed array of spacecraft offer a unique advantage to study the Earth's albedo. This paper presents the flight dynamics analysis performed in the context of the Leonardo-BRDF science requirements. First, the albedo integral is investigated and the effect of viewing geometry on science return is studied. The method used in this paper, based on Gauss quadrature, provides the optimal formation geometry to ensure that the value of the integral is accurately approximated. An orbit design approach is presented to achieve specific relative orbit geometries while simultaneously satisfying orbit dynamics constraints to reduce formation-keeping fuel expenditure. The relative geometry afforded by the design is discussed in terms of mission requirements. An optimal Lambert initialization scheme is presented with the required Delta-V to distribute all spacecraft from a common parking orbit into their appropriate orbits in the formation. Finally, formation-keeping strategies are developed and the associated Delta-V's are calculated to maintain the formation in the presence of perturbations.

  13. Dynamic modeling and ascent flight control of Ares-I Crew Launch Vehicle

    Science.gov (United States)

    Du, Wei

    This research focuses on dynamic modeling and ascent flight control of large flexible launch vehicles such as the Ares-I Crew Launch Vehicle (CLV). A complete set of six-degrees-of-freedom dynamic models of the Ares-I, incorporating its propulsion, aerodynamics, guidance and control, and structural flexibility, is developed. NASA's Ares-I reference model and the SAVANT Simulink-based program are utilized to develop a Matlab-based simulation and linearization tool for an independent validation of the performance and stability of the ascent flight control system of large flexible launch vehicles. A linearized state-space model as well as a non-minimum-phase transfer function model (which is typical for flexible vehicles with non-collocated actuators and sensors) are validated for ascent flight control design and analysis. This research also investigates fundamental principles of flight control analysis and design for launch vehicles, in particular the classical "drift-minimum" and "load-minimum" control principles. It is shown that an additional feedback of angle-of-attack can significantly improve overall performance and stability, especially in the presence of unexpected large wind disturbances. For a typical "non-collocated actuator and sensor" control problem for large flexible launch vehicles, non-minimum-phase filtering of "unstably interacting" bending modes is also shown to be effective. The uncertainty model of a flexible launch vehicle is derived. The robust stability of an ascent flight control system design, which directly controls the inertial attitude-error quaternion and also employs the non-minimum-phase filters, is verified by the framework of structured singular value (mu) analysis. Furthermore, nonlinear coupled dynamic simulation results are presented for a reference model of the Ares-I CLV as another validation of the feasibility of the ascent flight control system design. Another important issue for a single main engine launch vehicle is

  14. Synthetic Vision System Commercial Aircraft Flight Deck Display Technologies for Unusual Attitude Recovery

    Science.gov (United States)

    Prinzel, Lawrence J., III; Ellis, Kyle E.; Arthur, Jarvis J.; Nicholas, Stephanie N.; Kiggins, Daniel

    2017-01-01

    A Commercial Aviation Safety Team (CAST) study of 18 worldwide loss-of-control accidents and incidents determined that the lack of external visual references was associated with a flight crew's loss of attitude awareness or energy state awareness in 17 of these events. Therefore, CAST recommended development and implementation of virtual day-Visual Meteorological Condition (VMC) display systems, such as synthetic vision systems, which can promote flight crew attitude awareness similar to a day-VMC environment. This paper describes the results of a high-fidelity, large transport aircraft simulation experiment that evaluated virtual day-VMC displays and a "background attitude indicator" concept as an aid to pilots in recovery from unusual attitudes. Twelve commercial airline pilots performed multiple unusual attitude recoveries and both quantitative and qualitative dependent measures were collected. Experimental results and future research directions under this CAST initiative and the NASA "Technologies for Airplane State Awareness" research project are described.

  15. Efficient Neural Network Modeling for Flight and Space Dynamics Simulation

    Directory of Open Access Journals (Sweden)

    Ayman Hamdy Kassem

    2011-01-01

    Full Text Available This paper represents an efficient technique for neural network modeling of flight and space dynamics simulation. The technique will free the neural network designer from guessing the size and structure for the required neural network model and will help to minimize the number of neurons. For linear flight/space dynamics systems, the technique can find the network weights and biases directly by solving a system of linear equations without the need for training. Nonlinear flight dynamic systems can be easily modeled by training its linearized models keeping the same network structure. The training is fast, as it uses the linear system knowledge to speed up the training process. The technique is tested on different flight/space dynamic models and showed promising results.

  16. Unified Nonlinear Flight Dynamics and Aeroelastic Simulator Tool, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. (ZONA) proposes a R&D effort to develop a Unified Nonlinear Flight Dynamics and Aeroelastic Simulator (UNFDAS) Tool that will combine...

  17. Cross-cultural attitudes of flight crew regarding CRM

    Science.gov (United States)

    Merritt, Ashleigh

    1993-01-01

    This study asks if the Cockpit Management Attitude Questionnaire (CMAQ) can detect differences across countries, and/or across occupations. And if so, can those differences be interpreted? Research has shown that the CMAQ is sensitive to attitude differences between and within organizations, thereby demonstrating its effectiveness with American populations. But the CMAQ was originally designed by American researchers and psychometrically refined for American pilots. The items in the questionnaire, though general in nature, still reflect the ubiquitous Western bias, because the items were written by researchers from and for the one culture. Recognizing this constraint, this study is nonetheless interested in attitudes toward crew behavior, and how those attitudes may vary across country and occupation.

  18. The determination of the attitude and attitude dynamics of TeamSat

    DEFF Research Database (Denmark)

    Betto, Maurizio; Jørgensen, John Leif; Riis, Troels

    1999-01-01

    , in space, multiple autonomous processes intended for spacecraft applications such as autonomous star identification, attitude determination and identification and tracking of non-stellar objects, imaging and real-time compression of image and science data for further ground analysis. AVS successfully...... determined the attitude and attitude dynamics of TeamSat....

  19. Initial virtual flight test for a dynamically similar aircraft model with control augmentation system

    Directory of Open Access Journals (Sweden)

    Linliang Guo

    2017-04-01

    Full Text Available To satisfy the validation requirements of flight control law for advanced aircraft, a wind tunnel based virtual flight testing has been implemented in a low speed wind tunnel. A 3-degree-of-freedom gimbal, ventrally installed in the model, was used in conjunction with an actively controlled dynamically similar model of aircraft, which was equipped with the inertial measurement unit, attitude and heading reference system, embedded computer and servo-actuators. The model, which could be rotated around its center of gravity freely by the aerodynamic moments, together with the flow field, operator and real time control system made up the closed-loop testing circuit. The model is statically unstable in longitudinal direction, and it can fly stably in wind tunnel with the function of control augmentation of the flight control laws. The experimental results indicate that the model responds well to the operator’s instructions. The response of the model in the tests shows reasonable agreement with the simulation results. The difference of response of angle of attack is less than 0.5°. The effect of stability augmentation and attitude control law was validated in the test, meanwhile the feasibility of virtual flight test technique treated as preliminary evaluation tool for advanced flight vehicle configuration research was also verified.

  20. A Flight Dynamic Model of Aircraft Spinning

    Science.gov (United States)

    1990-06-01

    r Zaw rate about body axes S Aircraft wing area V Flight path velocity 3 a Angle of attack Sideslip angle 6, Aileron deflection, positive when right...Tests, May/June 1983 PartI. Unpublished data report. 6. MARTIN, C.A. and SECOMB, D.A. ; RAAF BPTA Phase II Wind Tun - nel Tests: Rotary Balance Tests

  1. On the modelling of gyroplane flight dynamics

    Science.gov (United States)

    Houston, Stewart; Thomson, Douglas

    2017-01-01

    The study of the gyroplane, with a few exceptions, is largely neglected in the literature which is indicative of a niche configuration limited to the sport and recreational market where resources are limited. However the contemporary needs of an informed population of owners and constructors, as well as the possibility of a wider application of such low-cost rotorcraft in other roles, suggests that an examination of the mathematical modelling requirements for the study of gyroplane flight mechanics is timely. Rotorcraft mathematical modelling has become stratified in three levels, each one defining the inclusion of various layers of complexity added to embrace specific modelling features as well as an attempt to improve fidelity. This paper examines the modelling of gyroplane flight mechanics in the context of this complexity, and shows that relatively simple formulations are adequate for capturing most aspects of gyroplane trim, stability and control characteristics. In particular the conventional 6 degree-of-freedom model structure is suitable for the synthesis of models from flight test data as well as being the framework for reducing the order of the higher levels of modelling. However, a high level of modelling can be required to mimic some aspects of behaviour observed in data gathered from flight experiments and even then can fail to capture other details. These limitations are addressed in the paper. It is concluded that the mathematical modelling of gyroplanes for the simulation and analysis of trim, stability and control presents no special difficulty and the conventional techniques, methods and formulations familiar to the rotary-wing community are directly applicable.

  2. Using Automatic Code Generation in the Attitude Control Flight Software Engineering Process

    Science.gov (United States)

    McComas, David; O'Donnell, James R., Jr.; Andrews, Stephen F.

    1999-01-01

    This paper presents an overview of the attitude control subsystem flight software development process, identifies how the process has changed due to automatic code generation, analyzes each software development phase in detail, and concludes with a summary of our lessons learned.

  3. GROSS- GAMMA RAY OBSERVATORY ATTITUDE DYNAMICS SIMULATOR

    Science.gov (United States)

    Garrick, J.

    1994-01-01

    The Gamma Ray Observatory (GRO) spacecraft will constitute a major advance in gamma ray astronomy by offering the first opportunity for comprehensive observations in the range of 0.1 to 30,000 megaelectronvolts (MeV). The Gamma Ray Observatory Attitude Dynamics Simulator, GROSS, is designed to simulate this mission. The GRO Dynamics Simulator consists of three separate programs: the Standalone Profile Program; the Simulator Program, which contains the Simulation Control Input/Output (SCIO) Subsystem, the Truth Model (TM) Subsystem, and the Onboard Computer (OBC) Subsystem; and the Postprocessor Program. The Standalone Profile Program models the environment of the spacecraft and generates a profile data set for use by the simulator. This data set contains items such as individual external torques; GRO spacecraft, Tracking and Data Relay Satellite (TDRS), and solar and lunar ephemerides; and star data. The Standalone Profile Program is run before a simulation. The SCIO subsystem is the executive driver for the simulator. It accepts user input, initializes parameters, controls simulation, and generates output data files and simulation status display. The TM subsystem models the spacecraft dynamics, sensors, and actuators. It accepts ephemerides, star data, and environmental torques from the Standalone Profile Program. With these and actuator commands from the OBC subsystem, the TM subsystem propagates the current state of the spacecraft and generates sensor data for use by the OBC and SCIO subsystems. The OBC subsystem uses sensor data from the TM subsystem, a Kalman filter (for attitude determination), and control laws to compute actuator commands to the TM subsystem. The OBC subsystem also provides output data to the SCIO subsystem for output to the analysts. The Postprocessor Program is run after simulation is completed. It generates printer and CRT plots and tabular reports of the simulated data at the direction of the user. GROSS is written in FORTRAN 77 and

  4. The dynamics of CRM attitude change: Attitude stability

    Science.gov (United States)

    Gregorich, Steven E.

    1993-01-01

    Special training seminars in cockpit resource management (CRM) are designed to enhance crew effectiveness in multicrew air-transport cockpits. In terms of CRM, crew effectiveness is defined by teamwork rather than technical proficiency. These seminars are designed to promote factual learning, alter aviator attitudes, and motivate aviators to make use of what they have learned. However, measures of attitude change resulting from CRM seminars have been the most common seminar evaluation technique. The current investigation explores a broader range of attitude change parameters with specific emphasis on the stability of change between recurrent visits to the training center. This allows for a comparison of training program strengths in terms of seminar ability to effect lasting change.

  5. Flight results of attitude matching between Space Shuttle and Inertial Upper Stage (IUS) navigation systems

    Science.gov (United States)

    Treder, Alfred J.; Meldahl, Keith L.

    The recorded histories of Shuttle/Orbiter attitude and Inertial Upper Stage (IUS) attitude have been analyzed for all joint flights of the IUS in the Orbiter. This database was studied to determine the behavior of relative alignment between the IUS and Shuttle navigation systems. It is found that the overall accuracy of physical alignment has a Shuttle Orbiter bias component less than 5 arcmin/axis and a short-term stability upper bound of 0.5 arcmin/axis, both at 1 sigma. Summaries of the experienced physical and inertial alginment offsets are shown in this paper, together with alignment variation data, illustrated with some flight histories. Also included is a table of candidate values for some error source groups in an Orbiter/IUS attitude errror model. Experience indicates that the Shuttle is much more accurate and stable as an orbiting launch platform than has so far been advertised. This information will be valuable for future Shuttle payloads, especially those (such as the Aeroassisted Flight Experiment) which carry their own inertial navigation systems, and which could update or initialize their attitude determination systems using the Shuttle as the reference.

  6. Nonlinear flight dynamics and stability of hovering model insects

    Science.gov (United States)

    Liang, Bin; Sun, Mao

    2013-01-01

    Current analyses on insect dynamic flight stability are based on linear theory and limited to small disturbance motions. However, insects' aerial environment is filled with swirling eddies and wind gusts, and large disturbances are common. Here, we numerically solve the equations of motion coupled with the Navier–Stokes equations to simulate the large disturbance motions and analyse the nonlinear flight dynamics of hovering model insects. We consider two representative model insects, a model hawkmoth (large size, low wingbeat frequency) and a model dronefly (small size, high wingbeat frequency). For small and large initial disturbances, the disturbance motion grows with time, and the insects tumble and never return to the equilibrium state; the hovering flight is inherently (passively) unstable. The instability is caused by a pitch moment produced by forward/backward motion and/or a roll moment produced by side motion of the insect. PMID:23697714

  7. In-flight Quality and Accuracy of Attitude Measurements from the CHAMP Advanced Stellar Compass

    DEFF Research Database (Denmark)

    Jørgensen, Peter Siegbjørn; Jørgensen, John Leif; Denver, Troelz

    2005-01-01

    The German geo-observations satellite CHAMP carries highly accurate vector instruments. The orientation of these relative to the inertial reference frame is obtained using star trackers. These advanced stellar compasses (ASC) are fully autonomous units, which provide, in real time, the absolute...... attitude with accuracy in the arc second range. In order to investigate the in-flight accuracy of the ASC, the terminology to characterize noise and biases is introduced. Relative instrument accuracy (RIA) and absolute instrument accuracy (AIA) can in principle be determined in-flight. However problems...

  8. Vertical Wind Tunnel for Prediction of Rocket Flight Dynamics

    Directory of Open Access Journals (Sweden)

    Hoani Bryson

    2016-03-01

    Full Text Available A customized vertical wind tunnel has been built by the University of Canterbury Rocketry group (UC Rocketry. This wind tunnel has been critical for the success of UC Rocketry as it allows the optimization of avionics and control systems before flight. This paper outlines the construction of the wind tunnel and includes an analysis of flow quality including swirl. A minimal modelling methodology for roll dynamics is developed that can extrapolate wind tunnel behavior at low wind speeds to much higher velocities encountered during flight. The models were shown to capture the roll flight dynamics in two rocket launches with mean roll angle errors varying from 0.26° to 1.5° across the flight data. The identified model parameters showed consistent and predictable variations over both wind tunnel tests and flight, including canard–fin interaction behavior. These results demonstrate that the vertical wind tunnel is an important tool for the modelling and control of sounding rockets.

  9. Coupled attitude-orbit dynamics and control for an electric sail in a heliocentric transfer mission.

    Science.gov (United States)

    Huo, Mingying; Zhao, Jun; Xie, Shaobiao; Qi, Naiming

    2015-01-01

    The paper discusses the coupled attitude-orbit dynamics and control of an electric-sail-based spacecraft in a heliocentric transfer mission. The mathematical model characterizing the propulsive thrust is first described as a function of the orbital radius and the sail angle. Since the solar wind dynamic pressure acceleration is induced by the sail attitude, the orbital and attitude dynamics of electric sails are coupled, and are discussed together. Based on the coupled equations, the flight control is investigated, wherein the orbital control is studied in an optimal framework via a hybrid optimization method and the attitude controller is designed based on feedback linearization control. To verify the effectiveness of the proposed control strategy, a transfer problem from Earth to Mars is considered. The numerical results show that the proposed strategy can control the coupled system very well, and a small control torque can control both the attitude and orbit. The study in this paper will contribute to the theory study and application of electric sail.

  10. Dynamical continuous time random Lévy flights

    Science.gov (United States)

    Liu, Jian; Chen, Xiaosong

    2016-03-01

    The Lévy flights' diffusive behavior is studied within the framework of the dynamical continuous time random walk (DCTRW) method, while the nonlinear friction is introduced in each step. Through the DCTRW method, Lévy random walker in each step flies by obeying the Newton's Second Law while the nonlinear friction f(v) = - γ0v - γ2v3 being considered instead of Stokes friction. It is shown that after introducing the nonlinear friction, the superdiffusive Lévy flights converges, behaves localization phenomenon with long time limit, but for the Lévy index μ = 2 case, it is still Brownian motion.

  11. Distributing flight dynamics products via the World Wide Web

    Science.gov (United States)

    Woodard, Mark; Matusow, David

    1996-01-01

    The NASA Flight Dynamics Products Center (FDPC), which make available selected operations products via the World Wide Web, is reported on. The FDPC can be accessed from any host machine connected to the Internet. It is a multi-mission service which provides Internet users with unrestricted access to the following standard products: antenna contact predictions; ground tracks; orbit ephemerides; mean and osculating orbital elements; earth sensor sun and moon interference predictions; space flight tracking data network summaries; and Shuttle transport system predictions. Several scientific data bases are available through the service.

  12. Operational computer graphics in the flight dynamics environment

    Science.gov (United States)

    Jeletic, James F.

    1989-01-01

    Over the past five years, the Flight Dynamics Division of the National Aeronautics and Space Administration's (NASA's) Goddard Space Flight Center has incorporated computer graphics technology into its operational environment. In an attempt to increase the effectiveness and productivity of the Division, computer graphics software systems have been developed that display spacecraft tracking and telemetry data in 2-d and 3-d graphic formats that are more comprehensible than the alphanumeric tables of the past. These systems vary in functionality from real-time mission monitoring system, to mission planning utilities, to system development tools. Here, the capabilities and architecture of these systems are discussed.

  13. Flight Dynamic Model Exchange using XML

    Science.gov (United States)

    Jackson, E. Bruce; Hildreth, Bruce L.

    2002-01-01

    The AIAA Modeling and Simulation Technical Committee has worked for several years to develop a standard by which the information needed to develop physics-based models of aircraft can be specified. The purpose of this standard is to provide a well-defined set of information, definitions, data tables and axis systems so that cooperating organizations can transfer a model from one simulation facility to another with maximum efficiency. This paper proposes using an application of the eXtensible Markup Language (XML) to implement the AIAA simulation standard. The motivation and justification for using a standard such as XML is discussed. Necessary data elements to be supported are outlined. An example of an aerodynamic model as an XML file is given. This example includes definition of independent and dependent variables for function tables, definition of key variables used to define the model, and axis systems used. The final steps necessary for implementation of the standard are presented. Software to take an XML-defined model and import/export it to/from a given simulation facility is discussed, but not demonstrated. That would be the next step in final implementation of standards for physics-based aircraft dynamic models.

  14. Dynamic Flight Simulation Utilizing High Fidelity CFD-Based Nonlinear Reduced Order Model, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Nonlinear Dynamic Flight Simulation (NL-DFS) system will be developed in the Phase II project by combining the classical nonlinear rigid-body flight dynamics...

  15. A Dynamic Attitude Measurement System Based on LINS

    Directory of Open Access Journals (Sweden)

    Hanzhou Li

    2014-08-01

    Full Text Available A dynamic attitude measurement system (DAMS is developed based on a laser inertial navigation system (LINS. Three factors of the dynamic attitude measurement error using LINS are analyzed: dynamic error, time synchronization and phase lag. An optimal coning errors compensation algorithm is used to reduce coning errors, and two-axis wobbling verification experiments are presented in the paper. The tests indicate that the attitude accuracy is improved 2-fold by the algorithm. In order to decrease coning errors further, the attitude updating frequency is improved from 200 Hz to 2000 Hz. At the same time, a novel finite impulse response (FIR filter with three notches is designed to filter the dither frequency of the ring laser gyro (RLG. The comparison tests suggest that the new filter is five times more effective than the old one. The paper indicates that phase-frequency characteristics of FIR filter and first-order holder of navigation computer constitute the main sources of phase lag in LINS. A formula to calculate the LINS attitude phase lag is introduced in the paper. The expressions of dynamic attitude errors induced by phase lag are derived. The paper proposes a novel synchronization mechanism that is able to simultaneously solve the problems of dynamic test synchronization and phase compensation. A single-axis turntable and a laser interferometer are applied to verify the synchronization mechanism. The experiments results show that the theoretically calculated values of phase lag and attitude error induced by phase lag can both match perfectly with testing data. The block diagram of DAMS and physical photos are presented in the paper. The final experiments demonstrate that the real-time attitude measurement accuracy of DAMS can reach up to 20″ (1σ and the synchronization error is less than 0.2 ms on the condition of three axes wobbling for 10 min.

  16. A Dynamic Attitude Measurement System Based on LINS

    Science.gov (United States)

    Li, Hanzhou; Pan, Quan; Wang, Xiaoxu; Zhang, Juanni; Li, Jiang; Jiang, Xiangjun

    2014-01-01

    A dynamic attitude measurement system (DAMS) is developed based on a laser inertial navigation system (LINS). Three factors of the dynamic attitude measurement error using LINS are analyzed: dynamic error, time synchronization and phase lag. An optimal coning errors compensation algorithm is used to reduce coning errors, and two-axis wobbling verification experiments are presented in the paper. The tests indicate that the attitude accuracy is improved 2-fold by the algorithm. In order to decrease coning errors further, the attitude updating frequency is improved from 200 Hz to 2000 Hz. At the same time, a novel finite impulse response (FIR) filter with three notches is designed to filter the dither frequency of the ring laser gyro (RLG). The comparison tests suggest that the new filter is five times more effective than the old one. The paper indicates that phase-frequency characteristics of FIR filter and first-order holder of navigation computer constitute the main sources of phase lag in LINS. A formula to calculate the LINS attitude phase lag is introduced in the paper. The expressions of dynamic attitude errors induced by phase lag are derived. The paper proposes a novel synchronization mechanism that is able to simultaneously solve the problems of dynamic test synchronization and phase compensation. A single-axis turntable and a laser interferometer are applied to verify the synchronization mechanism. The experiments results show that the theoretically calculated values of phase lag and attitude error induced by phase lag can both match perfectly with testing data. The block diagram of DAMS and physical photos are presented in the paper. The final experiments demonstrate that the real-time attitude measurement accuracy of DAMS can reach up to 20″ (1σ) and the synchronization error is less than 0.2 ms on the condition of three axes wobbling for 10 min. PMID:25177802

  17. Aircraft Landing and Attitude Control Using Dynamic Matrix Control

    Directory of Open Access Journals (Sweden)

    George Cristian Calugaru

    2017-06-01

    Full Text Available This paper proposes a method for an efficient control of the aircraft landing and attitude through Dynamic Matrix Control. The idea of MPC structures used in aircraft control has been well established during the last few years, but some aspects require further investigation. With this in mind, the paper proposes structures for aircraft landing and aircraft attitude control by using single DMC controllers for landing and respectively one DMC controller for each of the attitude axis (pitch attitude hold, bank angle hold and heading hold. The model used for analysis of the aircraft landing structure is based on the last phase of landing. Also, the model used to illustrate the attitude control is that of a pitch attitude hold system of a N250-100 aircraft. Simulations are performed for a variety of control and prediction horizons, taking into account the possibility of adding a weighting factor for the control actions. Apart from separate studies on step reference variations, for some use cases, a generic reference trajectory is provided as a control purpose of the system. Results show a better performance of the proposed method in terms of control surface transition and protection of the actuators involved and a better time response in stabilizing the aircraft attitude. Overall, the aspects shown ensure an improved aircraft attitude control and landing stabilization.

  18. Low Density Supersonic Decelerator Flight Dynamics Test-1 Flight Design and Targeting

    Science.gov (United States)

    Ivanov, Mark

    2015-01-01

    NASA's Low Density Supersonic Decelerator (LDSD) program was established to identify, develop, and eventually qualify to Test [i.e. Technology] Readiness Level (TRL) - 6 aerodynamic decelerators for eventual use on Mars. Through comprehensive Mars application studies, two distinct Supersonic Inflatable Aerodynamic Decelerator (SIAD) designs were chosen that afforded the optimum balance of benefit, cost, and development risk. In addition, a Supersonic Disk Sail (SSDS) parachute design was chosen that satisfied the same criteria. The final phase of the multi-tiered qualification process involves Earth Supersonic Flight Dynamics Tests (SFDTs) within environmental conditions similar to those that would be experienced during a Mars Entry, Descent, and Landing (EDL) mission. The first of these flight tests (i.e. SFDT-1) was completed on June 28, 2014 with two more tests scheduled for the summer of 2015 and 2016, respectively. The basic flight design for all the SFDT flights is for the SFDT test vehicle to be ferried to a float altitude of 120 kilo-feet by a 34 thousand cubic feet (Mcf) heavy lift helium balloon. Once float altitude is reached, the test vehicle is released from the balloon, spun-up for stability, and accelerated to supersonic speeds using a Star48 solid rocket motor. After burnout of the Star48 motor the vehicle decelerates to pre-flight selected test conditions for the deployment of the SIAD system. After further deceleration with the SIAD deployed, the SSDS parachute is then deployed stressing the performance of the parachute in the wake of the SIAD augmented blunt body. The test vehicle/SIAD/parachute system then descends to splashdown in the Pacific Ocean for eventual recovery. This paper will discuss the development of both the test vehicle and the trajectory sequence including design trade-offs resulting from the interaction of both engineering efforts. In addition, the SFDT-1 nominal trajectory design and associated sensitivities will be discussed

  19. Spacecraft Dynamics Should be Considered in Kalman Filter Attitude Estimation

    Science.gov (United States)

    Yang, Yaguang; Zhou, Zhiqiang

    2016-01-01

    Kalman filter based spacecraft attitude estimation has been used in some high-profile missions and has been widely discussed in literature. While some models in spacecraft attitude estimation include spacecraft dynamics, most do not. To our best knowledge, there is no comparison on which model is a better choice. In this paper, we discuss the reasons why spacecraft dynamics should be considered in the Kalman filter based spacecraft attitude estimation problem. We also propose a reduced quaternion spacecraft dynamics model which admits additive noise. Geometry of the reduced quaternion model and the additive noise are discussed. This treatment is more elegant in mathematics and easier in computation. We use some simulation example to verify our claims.

  20. Low Density Supersonic Decelerator (LDSD) Supersonic Flight Dynamics Test (SFDT) Plume Induced Environment Modelling

    Science.gov (United States)

    Mobley, B. L.; Smith, S. D.; Van Norman, J. W.; Muppidi, S.; Clark, I

    2016-01-01

    Provide plume induced heating (radiation & convection) predictions in support of the LDSD thermal design (pre-flight SFDT-1) Predict plume induced aerodynamics in support of flight dynamics, to achieve targeted freestream conditions to test supersonic deceleration technologies (post-flight SFDT-1, pre-flight SFDT-2)

  1. A mathematical perspective on flight dynamics and control

    CERN Document Server

    L'Afflitto, Andrea

    2017-01-01

    This brief presents several aspects of flight dynamics, which are usually omitted or briefly mentioned in textbooks, in a concise, self-contained, and rigorous manner. The kinematic and dynamic equations of an aircraft are derived starting from the notion of the derivative of a vector and then thoroughly analysed, interpreting their deep meaning from a mathematical standpoint and without relying on physical intuition. Moreover, some classic and advanced control design techniques are presented and illustrated with meaningful examples. Distinguishing features that characterize this brief include a definition of angular velocity, which leaves no room for ambiguities, an improvement on traditional definitions based on infinitesimal variations. Quaternion algebra, Euler parameters, and their role in capturing the dynamics of an aircraft are discussed in great detail. After having analyzed the longitudinal- and lateral-directional modes of an aircraft, the linear-quadratic regulator, the linear-quadratic Gaussian r...

  2. Robust flight control using incremental nonlinear dynamic inversion and angular acceleration prediction

    NARCIS (Netherlands)

    Sieberling, S.; Chu, Q.P.; Mulder, J.A.

    2010-01-01

    This paper presents a flight control strategy based on nonlinear dynamic inversion. The approach presented, called incremental nonlinear dynamic inversion, uses properties of general mechanical systems and nonlinear dynamic inversion by feeding back angular accelerations. Theoretically, feedback of

  3. Basic Coandă MAV Fluid Dynamics and Flight Mechanics

    Science.gov (United States)

    Djojodihardjo, H.; Ahmed, RI

    2017-04-01

    Capitalizing on the basic fundamental principles, the Fluid Dynamics and Flight Mechanics of a semi-spherical Coandă MAV configurations are revisited and analyzed as a baseline. A mathematical model for a spherical Coandă MAV in hover and translatory motion is developed and analyzed from first physical principles. To gain further insight into the prevailing flow field around a Coandă MAV, as well as to verify the theoretical prediction presented in the work, a computational fluid dynamic CFD simulations for a Coandă MAV generic model are elaborated. The mathematical model and derived performance measures are shown to be capable in describing the physical phenomena of the flow field of the semi-spherical Coandă MAV. The relationships between the relevant parameters of the mathematical model of the Coandă MAV to the forces acting on it are elaborated subsequently.

  4. Attitude Control System Design for the Solar Dynamics Observatory

    Science.gov (United States)

    Starin, Scott R.; Bourkland, Kristin L.; Kuo-Chia, Liu; Mason, Paul A. C.; Vess, Melissa F.; Andrews, Stephen F.; Morgenstern, Wendy M.

    2005-01-01

    The Solar Dynamics Observatory mission, part of the Living With a Star program, will place a geosynchronous satellite in orbit to observe the Sun and relay data to a dedicated ground station at all times. SDO remains Sun- pointing throughout most of its mission for the instruments to take measurements of the Sun. The SDO attitude control system is a single-fault tolerant design. Its fully redundant attitude sensor complement includes 16 coarse Sun sensors, a digital Sun sensor, 3 two-axis inertial reference units, 2 star trackers, and 4 guide telescopes. Attitude actuation is performed using 4 reaction wheels and 8 thrusters, and a single main engine nominally provides velocity-change thrust. The attitude control software has five nominal control modes-3 wheel-based modes and 2 thruster-based modes. A wheel-based Safehold running in the attitude control electronics box improves the robustness of the system as a whole. All six modes are designed on the same basic proportional-integral-derivative attitude error structure, with more robust modes setting their integral gains to zero. The paper details the mode designs and their uses.

  5. Proceedings of the 20th International Symposium on Space Flight Dynamics

    Science.gov (United States)

    Woodard, Mark (Editor); Stengle, Tom (Editor)

    2007-01-01

    Topics include: Measuring Image Navigation and Registration Performance at the 3-Sigma Level Using Platinum Quality Landmarks; Flight Dynamics Performances of the MetOp A Satellite during the First Months of Operations; Visual Navigation - SARE Mission; Determining a Method of Enabling and Disabling the Integral Torque in the SDO Science and Inertial Mode Controllers; Guaranteeing Pointing Performance of the SDO Sun-Pointing Controllers in Light of Nonlinear Effects; SDO Delta H Mode Design and Analysis; Observing Mode Attitude Controller for the Lunar Reconnaissance Orbiter; Broken-Plane Maneuver Applications for Earth to Mars Trajectories; ExoMars Mission Analysis and Design - Launch, Cruise and Arrival Analyses; Mars Reconnaissance Orbiter Aerobraking Daily Operations and Collision Avoidance; Mars Reconnaissance Orbiter Interplanetary Cruise Navigation; Motion Parameters Determination of the SC and Phobos in the Project Phobos-Grunt; GRAS NRT Precise Orbit Determination: Operational Experience; Orbit Determination of LEO Satellites for a Single Pass through a Radar: Comparison of Methods; Orbit Determination System for Low Earth Orbit Satellites; Precise Orbit Determination for ALOS; Anti-Collision Function Design and Performances of the CNES Formation Flying Experiment on the PRISMA Mission; CNES Approaching Guidance Experiment within FFIORD; Maneuver Recovery Analysis for the Magnetospheric Multiscale Mission; SIMBOL-X: A Formation Flying Mission on HEO for Exploring the Universe; Spaceborne Autonomous and Ground Based Relative Orbit Control for the TerraSAR-X/TanDEM-X Formation; First In-Orbit Experience of TerraSAR-X Flight Dynamics Operations; Automated Target Planning for FUSE Using the SOVA Algorithm; Space Technology 5 Post-Launch Ground Attitude Estimation Experience; Standardizing Navigation Data: A Status Update; and A Study into the Method of Precise Orbit Determination of a HEO Orbiter by GPS and Accelerometer.

  6. Dipteran insect flight dynamics. Part 1 Longitudinal motion about hover.

    Science.gov (United States)

    Faruque, Imraan; Sean Humbert, J

    2010-05-21

    This paper presents a reduced-order model of longitudinal hovering flight dynamics for dipteran insects. The quasi-steady wing aerodynamics model is extended by including perturbation states from equilibrium and paired with rigid body equations of motion to create a nonlinear simulation of a Drosophila-like insect. Frequency-based system identification tools are used to identify the transfer functions from biologically inspired control inputs to rigid body states. Stability derivatives and a state space linear system describing the dynamics are also identified. The vehicle control requirements are quantified with respect to traditional human pilot handling qualities specification. The heave dynamics are found to be decoupled from the pitch/fore/aft dynamics. The haltere-on system revealed a stabilized system with a slow (heave) and fast subsidence mode, and a stable oscillatory mode. The haltere-off (bare airframe) system revealed a slow (heave) and fast subsidence mode and an unstable oscillatory mode, a modal structure in agreement with CFD studies. The analysis indicates that passive aerodynamic mechanisms contribute to stability, which may help explain how insects are able to achieve stable locomotion on a very small computational budget. Copyright (c) 2010. Published by Elsevier Ltd.

  7. Improvements in flight table dynamic transparency for hardware-in-the-loop facilities

    Science.gov (United States)

    DeMore, Louis A.; Mackin, Rob; Swamp, Michael; Rusterholtz, Roger

    2000-07-01

    Flight tables are a 'necessary evil' in the Hardware-In-The- Loop (HWIL) simulation. Adding the actual or prototypic flight hardware to the loop, in order to increase the realism of the simulation, forces us to add motion simulation to the process. Flight table motion bases bring unwanted dynamics, non- linearities, transport delays, etc to an already difficult problem sometimes requiring the simulation engineer to compromise the results. We desire that the flight tables be 'dynamically transparent' to the simulation scenario. This paper presents a State Variable Feedback (SVF) control system architecture with feed-forward techniques that improves the flight table's dynamic transparency by significantly reducing the table's low frequency phase lag. We offer some actual results with existing flight tables that demonstrate the improved transparency. These results come from a demonstration conducted on a flight table in the KHILS laboratory at Eglin AFB and during a refurbishment of a flight table for the Boeing Company of St. Charles, Missouri.

  8. NanoSail - D Orbital and Attitude Dynamics

    Science.gov (United States)

    Heaton, Andrew F.; Faller, Brent F.; Katan, Chelsea K.

    2013-01-01

    NanoSail-D unfurled January 20th, 2011 and successfully demonstrated the deployment and deorbit capability of a solar sail in low Earth orbit. The orbit was strongly perturbed by solar radiation pressure, aerodynamic drag, and oblate gravity which were modeled using STK HPOP. A comparison of the ballistic coefficient history to the orbit parameters exhibits a strong relationship between orbital lighting, the decay rate of the mean semi-major axis and mean eccentricity. A similar comparison of mean solar area using the STK HPOP solar radiation pressure model exhibits a strong correlation of solar radiation pressure to mean eccentricity and mean argument of perigee. NanoSail-D was not actively controlled and had no capability on-board for attitude or orbit determination. To estimate attitude dynamics we created a 3-DOF attitude dynamics simulation that incorporated highly realistic estimates of perturbing forces into NanoSail-D torque models. By comparing the results of this simulation to the orbital behavior and ground observations of NanoSail-D, we conclude that there is a coupling between the orbit and attitude dynamics as well as establish approximate limits on the location of the NanoSail-D solar center of pressure. Both of these observations contribute valuable data for future solar sail designs and missions.

  9. Parachute-Payload System Flight Dynamics and Trajectory Simulation

    Directory of Open Access Journals (Sweden)

    Giorgio Guglieri

    2012-01-01

    Full Text Available The work traces a general procedure for the design of a flight simulation tool still representative of the major flight physics of a parachute-payload system along decelerated trajectories. An example of limited complexity simulation models for a payload decelerated by one or more parachutes is given, including details and implementation features usually omitted as the focus of the research in this field is typically on the investigation of mission design issues, rather than addressing general implementation guidelines for the development of a reconfigurable simulation tool. The dynamics of the system are modeled through a simple multibody model that represents the expected behavior of an entry vehicle during the terminal deceleration phase. The simulators are designed according to a comprehensive vision that enforces the simplification of the coupling mechanism between the payload and the parachute, with an adequate level of physical insight still available. The results presented for a realistic case study define the sensitivity of the simulation outputs to the functional complexity of the mathematical model. Far from being an absolute address for the software designer, this paper tries to contribute to the area of interest with some technical considerations and clarifications.

  10. OSIRIS-REx Flight Dynamics and Navigation Design

    Science.gov (United States)

    Williams, B.; Antreasian, P.; Carranza, E.; Jackman, C.; Leonard, J.; Nelson, D.; Page, B.; Stanbridge, D.; Wibben, D.; Williams, K.; Moreau, M.; Berry, K.; Getzandanner, K.; Liounis, A.; Mashiku, A.; Highsmith, D.; Sutter, B.; Lauretta, D. S.

    2018-06-01

    OSIRIS-REx is the first NASA mission to return a sample of an asteroid to Earth. Navigation and flight dynamics for the mission to acquire and return a sample of asteroid 101955 Bennu establish many firsts for space exploration. These include relatively small orbital maneuvers that are precise to ˜1 mm/s, close-up operations in a captured orbit about an asteroid that is small in size and mass, and planning and orbit phasing to revisit the same spot on Bennu in similar lighting conditions. After preliminary surveys and close approach flyovers of Bennu, the sample site will be scientifically characterized and selected. A robotic shock-absorbing arm with an attached sample collection head mounted on the main spacecraft bus acquires the sample, requiring navigation to Bennu's surface. A touch-and-go sample acquisition maneuver will result in the retrieval of at least 60 grams of regolith, and up to several kilograms. The flight activity concludes with a return cruise to Earth and delivery of the sample return capsule (SRC) for landing and sample recovery at the Utah Test and Training Range (UTTR).

  11. Reentry Vehicle Flight Controls Design Guidelines: Dynamic Inversion

    Science.gov (United States)

    Ito, Daigoro; Georgie, Jennifer; Valasek, John; Ward, Donald T.

    2002-01-01

    This report addresses issues in developing a flight control design for vehicles operating across a broad flight regime and with highly nonlinear physical descriptions of motion. Specifically it addresses the need for reentry vehicles that could operate through reentry from space to controlled touchdown on Earth. The latter part of controlled descent is achieved by parachute or paraglider - or by all automatic or a human-controlled landing similar to that of the Orbiter. Since this report addresses the specific needs of human-carrying (not necessarily piloted) reentry vehicles, it deals with highly nonlinear equations of motion, and then-generated control systems must be robust across a very wide range of physics. Thus, this report deals almost exclusively with some form of dynamic inversion (DI). Two vital aspects of control theory - noninteracting control laws and the transformation of nonlinear systems into equivalent linear systems - are embodied in DI. Though there is no doubt that the mathematical tools and underlying theory are widely available, there are open issues as to the practicality of using DI as the only or primary design approach for reentry articles. This report provides a set of guidelines that can be used to determine the practical usefulness of the technique.

  12. In-flight dynamics of volcanic ballistic projectiles

    Science.gov (United States)

    Taddeucci, J.; Alatorre-Ibargüengoitia, M. A.; Cruz-Vázquez, O.; Del Bello, E.; Scarlato, P.; Ricci, T.

    2017-09-01

    Centimeter to meter-sized volcanic ballistic projectiles from explosive eruptions jeopardize people and properties kilometers from the volcano, but they also provide information about the past eruptions. Traditionally, projectile trajectory is modeled using simplified ballistic theory, accounting for gravity and drag forces only and assuming simply shaped projectiles free moving through air. Recently, collisions between projectiles and interactions with plumes are starting to be considered. Besides theory, experimental studies and field mapping have so far dominated volcanic projectile research, with only limited observations. High-speed, high-definition imaging now offers a new spatial and temporal scale of observation that we use to illuminate projectile dynamics. In-flight collisions commonly affect the size, shape, trajectory, and rotation of projectiles according to both projectile nature (ductile bomb versus brittle block) and the location and timing of collisions. These, in turn, are controlled by ejection pulses occurring at the vent. In-flight tearing and fragmentation characterize large bombs, which often break on landing, both factors concurring to decrease the average grain size of the resulting deposits. Complex rotation and spinning are ubiquitous features of projectiles, and the related Magnus effect may deviate projectile trajectory by tens of degrees. A new relationship is derived, linking projectile velocity and size with the size of the resulting impact crater. Finally, apparent drag coefficient values, obtained for selected projectiles, mostly range from 1 to 7, higher than expected, reflecting complex projectile dynamics. These new perspectives will impact projectile hazard mitigation and the interpretation of projectile deposits from past eruptions, both on Earth and on other planets.

  13. Estimation of Gravitation Parameters of Saturnian Moons Using Cassini Attitude Control Flight Data

    Science.gov (United States)

    Krening, Samantha C.

    2013-01-01

    A major science objective of the Cassini mission is to study Saturnian satellites. The gravitational properties of each Saturnian moon is of interest not only to scientists but also to attitude control engineers. When the Cassini spacecraft flies close to a moon, a gravity gradient torque is exerted on the spacecraft due to the mass of the moon. The gravity gradient torque will alter the spin rates of the reaction wheels (RWA). The change of each reaction wheel's spin rate might lead to overspeed issues or operating the wheel bearings in an undesirable boundary lubrication condition. Hence, it is imperative to understand how the gravity gradient torque caused by a moon will affect the reaction wheels in order to protect the health of the hardware. The attitude control telemetry from low-altitude flybys of Saturn's moons can be used to estimate the gravitational parameter of the moon or the distance between the centers of mass of Cassini and the moon. Flight data from several low altitude flybys of three Saturnian moons, Dione, Rhea, and Enceladus, were used to estimate the gravitational parameters of these moons. Results are compared with values given in the literature.

  14. Hovering and Transition Flight Tests of a 1/5-Scale Model of a Jet-Powered Vertical-Attitude VTOL Research Airplane

    Science.gov (United States)

    Smith, Charles C., Jr.

    1961-01-01

    An experimental investigation has been made to determine the dynamic stability and control characteristics of a 1/5-scale flying model of a jet-powered vertical-attitude VTOL research airplane in hovering and transition flight. The model was powered with either a hydrogen peroxide rocket motor or a compressed-air jet exhausting through an ejector tube to simulate the turbojet engine of the airplane. The gyroscopic effects of the engine were simulated by a flywheel driven by compressed-air jets. In hovering flight the model was controlled by jet-reaction controls which consisted of a swiveling nozzle on the main jet and a movable nozzle on each wing tip; and in forward flight the model was controlled by elevons and a rudder. If the gyroscopic effects of the jet engine were not represented, the model could be flown satisfactorily in hovering flight without any automatic stabilization devices. When the gyroscopic effects of the jet engine were represented, however, the model could not be controlled without the aid of artificial stabilizing devices because of the gyroscopic coupling of the yawing and pitching motions. The use of pitch and yaw dampers made these motions completely stable and the model could then be controlled very easily. In the transition flight tests, which were performed only with the automatic pitch and yaw dampers operating, it was found that the transition was very easy to perform either with or without the engine gyroscopic effects simulated, although the model had a tendency to fly in a rolled and sideslipped attitude at angles of attack between approximately 25 deg and 45 deg because of static directional instability in this range.

  15. Flight code validation simulator

    Science.gov (United States)

    Sims, Brent A.

    1996-05-01

    An End-To-End Simulation capability for software development and validation of missile flight software on the actual embedded computer has been developed utilizing a 486 PC, i860 DSP coprocessor, embedded flight computer and custom dual port memory interface hardware. This system allows real-time interrupt driven embedded flight software development and checkout. The flight software runs in a Sandia Digital Airborne Computer and reads and writes actual hardware sensor locations in which Inertial Measurement Unit data resides. The simulator provides six degree of freedom real-time dynamic simulation, accurate real-time discrete sensor data and acts on commands and discretes from the flight computer. This system was utilized in the development and validation of the successful premier flight of the Digital Miniature Attitude Reference System in January of 1995 at the White Sands Missile Range on a two stage attitude controlled sounding rocket.

  16. Solar and Heliospheric Observatory (SOHO) Flight Dynamics Simulations Using MATLAB (R)

    Science.gov (United States)

    Headrick, R. D.; Rowe, J. N.

    1996-01-01

    This paper describes a study to verify onboard attitude control laws in the coarse Sun-pointing (CSP) mode by simulation and to develop procedures for operational support for the Solar and Heliospheric Observatory (SOHO) mission. SOHO was launched on December 2, 1995, and the predictions of the simulation were verified with the flight data. This study used a commercial off the shelf product MATLAB(tm) to do the following: Develop procedures for computing the parasitic torques for orbital maneuvers; Simulate onboard attitude control of roll, pitch, and yaw during orbital maneuvers; Develop procedures for predicting firing time for both on- and off-modulated thrusters during orbital maneuvers; Investigate the use of feed forward or pre-bias torques to reduce the attitude handoff during orbit maneuvers - in particular, determine how to use the flight data to improve the feed forward torque estimates for use on future maneuvers. The study verified the stability of the attitude control during orbital maneuvers and the proposed use of feed forward torques to compensate for the attitude handoff. Comparison of the simulations with flight data showed: Parasitic torques provided a good estimate of the on- and off-modulation for attitude control; The feed forward torque compensation scheme worked well to reduce attitude handoff during the orbital maneuvers. The work has been extended to prototype calibration of thrusters from observed firing time and observed reaction wheel speed changes.

  17. Interaction of feel system and flight control system dynamics on lateral flying qualities

    Science.gov (United States)

    Bailey, R. E.; Knotts, L. H.

    1990-01-01

    An experimental investigation of the influence of lateral feel system characteristics on fighter aircraft roll flying qualities was conducted using the variable stability USAF NT-33. Forty-two evaluation flights were flown by three engineering test pilots. The investigation utilized the power approach, visual landing task and up-and-away tasks including formation, gun tracking, and computer-generated compensatory attitude tracking tasks displayed on the Head-Up Display. Experimental variations included the feel system frequency, force-deflection gradient, control system command type (force or position input command), aircraft roll mode time constant, control system prefilter frequency, and control system time delay. The primary data were task performance records and evaluation pilot comments and ratings using the Cooper-Harper scale. The data highlight the unique and powerful effect of the feel system of flying qualities. The data show that the feel system is not 'equivalent' in flying qualities influence to analogous control system elements. A lower limit of allowable feel system frequency appears warranted to ensure good lateral flying qualities. Flying qualities criteria should most properly treat the feel system dynamic influence separately from the control system, since the input and output of this dynamic element is apparent to the pilot and thus, does not produce a 'hidden' effect.

  18. International Symposium on Spacecraft Ground Control and Flight Dynamics, SCD1, Sao Jose dos Campos, Brazil, Feb. 7-11, 1994

    Science.gov (United States)

    Rozenfeld, Pawel; Kuga, Helio Koiti; Orlando, Valcir

    An international symposium on spacecraft flight dynamics and ground control systems produced 85 papers in the areas of attitude determination and control, orbit control, satellite constellation strategies, stationkeeping, spacecraft maneuvering, orbit determination, astrodynamics, ground command and control systems, and mission operations. Several papers included discussions on the application of artificial intelligence, neural networks, expert systems, and ion propulsion. For individual titles, see A95-89098 through A95-89182.

  19. An Integrated Vision-Based System for Spacecraft Attitude and Topology Determination for Formation Flight Missions

    Science.gov (United States)

    Rogers, Aaron; Anderson, Kalle; Mracek, Anna; Zenick, Ray

    2004-01-01

    With the space industry's increasing focus upon multi-spacecraft formation flight missions, the ability to precisely determine system topology and the orientation of member spacecraft relative to both inertial space and each other is becoming a critical design requirement. Topology determination in satellite systems has traditionally made use of GPS or ground uplink position data for low Earth orbits, or, alternatively, inter-satellite ranging between all formation pairs. While these techniques work, they are not ideal for extension to interplanetary missions or to large fleets of decentralized, mixed-function spacecraft. The Vision-Based Attitude and Formation Determination System (VBAFDS) represents a novel solution to both the navigation and topology determination problems with an integrated approach that combines a miniature star tracker with a suite of robust processing algorithms. By combining a single range measurement with vision data to resolve complete system topology, the VBAFDS design represents a simple, resource-efficient solution that is not constrained to certain Earth orbits or formation geometries. In this paper, analysis and design of the VBAFDS integrated guidance, navigation and control (GN&C) technology will be discussed, including hardware requirements, algorithm development, and simulation results in the context of potential mission applications.

  20. Attitude Dynamics and Stability of a Simple Solar Photon Thruster

    Directory of Open Access Journals (Sweden)

    Anna D. Guerman

    2013-01-01

    Full Text Available This paper is dedicated to the development of a model of the attitude dynamics for a nonideal Simple Solar Photon Thruster (SSPT and to the analysis of sailcraft motions with respect to their centre of mass. Derivation of the expressions for force and torque due to solar radiation that is valid for the case, when there is a misalignment of the SSPT axis with the sun direction, is followed by study of sailcraft dynamics and stability properties. Analysis of stability shows that an ideally reflecting sail is unstable, while for a sailcraft with nonideal collector, the symmetry axis is stable with respect to the Sun direction for large variety of system parameters. The motion around symmetry axis is always unstable and requires an active stabilizer.

  1. Field Flight Dynamics of Hummingbirds during Territory Encroachment and Defense.

    Directory of Open Access Journals (Sweden)

    Katherine M Sholtis

    Full Text Available Hummingbirds are known to defend food resources such as nectar sources from encroachment by competitors (including conspecifics. These competitive intraspecific interactions provide an opportunity to quantify the biomechanics of hummingbird flight performance during ecologically relevant natural behavior. We recorded the three-dimensional flight trajectories of Ruby-throated Hummingbirds defending, being chased from and freely departing from a feeder. These trajectories allowed us to compare natural flight performance to earlier laboratory measurements of maximum flight speed, aerodynamic force generation and power estimates. During field observation, hummingbirds rarely approached the maximal flight speeds previously reported from wind tunnel tests and never did so during level flight. However, the accelerations and rates of change in kinetic and potential energy we recorded indicate that these hummingbirds likely operated near the maximum of their flight force and metabolic power capabilities during these competitive interactions. Furthermore, although birds departing from the feeder while chased did so faster than freely-departing birds, these speed gains were accomplished by modulating kinetic and potential energy gains (or losses rather than increasing overall power output, essentially trading altitude for speed during their evasive maneuver. Finally, the trajectories of defending birds were directed toward the position of the encroaching bird rather than the feeder.

  2. Field Flight Dynamics of Hummingbirds during Territory Encroachment and Defense.

    Science.gov (United States)

    Sholtis, Katherine M; Shelton, Ryan M; Hedrick, Tyson L

    2015-01-01

    Hummingbirds are known to defend food resources such as nectar sources from encroachment by competitors (including conspecifics). These competitive intraspecific interactions provide an opportunity to quantify the biomechanics of hummingbird flight performance during ecologically relevant natural behavior. We recorded the three-dimensional flight trajectories of Ruby-throated Hummingbirds defending, being chased from and freely departing from a feeder. These trajectories allowed us to compare natural flight performance to earlier laboratory measurements of maximum flight speed, aerodynamic force generation and power estimates. During field observation, hummingbirds rarely approached the maximal flight speeds previously reported from wind tunnel tests and never did so during level flight. However, the accelerations and rates of change in kinetic and potential energy we recorded indicate that these hummingbirds likely operated near the maximum of their flight force and metabolic power capabilities during these competitive interactions. Furthermore, although birds departing from the feeder while chased did so faster than freely-departing birds, these speed gains were accomplished by modulating kinetic and potential energy gains (or losses) rather than increasing overall power output, essentially trading altitude for speed during their evasive maneuver. Finally, the trajectories of defending birds were directed toward the position of the encroaching bird rather than the feeder.

  3. Flight Dynamics of Flexible Aircraft with Aeroelastic and Inertial Force Interactions

    Science.gov (United States)

    Nguyen, Nhan T.; Tuzcu, Ilhan

    2009-01-01

    This paper presents an integrated flight dynamic modeling method for flexible aircraft that captures coupled physics effects due to inertial forces, aeroelasticity, and propulsive forces that are normally present in flight. The present approach formulates the coupled flight dynamics using a structural dynamic modeling method that describes the elasticity of a flexible, twisted, swept wing using an equivalent beam-rod model. The structural dynamic model allows for three types of wing elastic motion: flapwise bending, chordwise bending, and torsion. Inertial force coupling with the wing elasticity is formulated to account for aircraft acceleration. The structural deflections create an effective aeroelastic angle of attack that affects the rigid-body motion of flexible aircraft. The aeroelastic effect contributes to aerodynamic damping forces that can influence aerodynamic stability. For wing-mounted engines, wing flexibility can cause the propulsive forces and moments to couple with the wing elastic motion. The integrated flight dynamics for a flexible aircraft are formulated by including generalized coordinate variables associated with the aeroelastic-propulsive forces and moments in the standard state-space form for six degree-of-freedom flight dynamics. A computational structural model for a generic transport aircraft has been created. The eigenvalue analysis is performed to compute aeroelastic frequencies and aerodynamic damping. The results will be used to construct an integrated flight dynamic model of a flexible generic transport aircraft.

  4. Flight test of the X-29A at high angle of attack: Flight dynamics and controls

    Science.gov (United States)

    Bauer, Jeffrey E.; Clarke, Robert; Burken, John J.

    1995-01-01

    The NASA Dryden Flight Research Center has flight tested two X-29A aircraft at low and high angles of attack. The high-angle-of-attack tests evaluate the feasibility of integrated X-29A technologies. More specific objectives focus on evaluating the high-angle-of-attack flying qualities, defining multiaxis controllability limits, and determining the maximum pitch-pointing capability. A pilot-selectable gain system allows examination of tradeoffs in airplane stability and maneuverability. Basic fighter maneuvers provide qualitative evaluation. Bank angle captures permit qualitative data analysis. This paper discusses the design goals and approach for high-angle-of-attack control laws and provides results from the envelope expansion and handling qualities testing at intermediate angles of attack. Comparisons of the flight test results to the predictions are made where appropriate. The pitch rate command structure of the longitudinal control system is shown to be a valid design for high-angle-of-attack control laws. Flight test results show that wing rock amplitude was overpredicted and aileron and rudder effectiveness were underpredicted. Flight tests show the X-29A airplane to be a good aircraft up to 40 deg angle of attack.

  5. Analysis of the flight dynamics of the Solar Maximum Mission (SMM) off-sun scientific pointing

    Science.gov (United States)

    Pitone, D. S.; Klein, J. R.; Twambly, B. J.

    1990-01-01

    Algorithms are presented which were created and implemented by the Goddard Space Flight Center's (GSFC's) Solar Maximum Mission (SMM) attitude operations team to support large-angle spacecraft pointing at scientific objectives. The mission objective of the post-repair SMM satellite was to study solar phenomena. However, because the scientific instruments, such as the Coronagraph/Polarimeter (CP) and the Hard X-ray Burst Spectrometer (HXRBS), were able to view objects other than the Sun, attitude operations support for attitude pointing at large angles from the nominal solar-pointing attitudes was required. Subsequently, attitude support for SMM was provided for scientific objectives such as Comet Halley, Supernova 1987A, Cygnus X-1, and the Crab Nebula. In addition, the analysis was extended to include the reverse problem, computing the right ascension and declination of a body given the off-Sun angles. This analysis led to the computation of the orbits of seven new solar comets seen in the field-of-view (FOV) of the CP. The activities necessary to meet these large-angle attitude-pointing sequences, such as slew sequence planning, viewing-period prediction, and tracking-bias computation are described. Analysis is presented for the computation of maneuvers and pointing parameters relative to the SMM-unique, Sun-centered reference frame. Finally, science data and independent attitude solutions are used to evaluate the larg-angle pointing performance.

  6. NASA Langley's AirSTAR Testbed: A Subscale Flight Test Capability for Flight Dynamics and Control System Experiments

    Science.gov (United States)

    Jordan, Thomas L.; Bailey, Roger M.

    2008-01-01

    As part of the Airborne Subscale Transport Aircraft Research (AirSTAR) project, NASA Langley Research Center (LaRC) has developed a subscaled flying testbed in order to conduct research experiments in support of the goals of NASA s Aviation Safety Program. This research capability consists of three distinct components. The first of these is the research aircraft, of which there are several in the AirSTAR stable. These aircraft range from a dynamically-scaled, twin turbine vehicle to a propeller driven, off-the-shelf airframe. Each of these airframes carves out its own niche in the research test program. All of the airplanes have sophisticated on-board data acquisition and actuation systems, recording, telemetering, processing, and/or receiving data from research control systems. The second piece of the testbed is the ground facilities, which encompass the hardware and software infrastructure necessary to provide comprehensive support services for conducting flight research using the subscale aircraft, including: subsystem development, integrated testing, remote piloting of the subscale aircraft, telemetry processing, experimental flight control law implementation and evaluation, flight simulation, data recording/archiving, and communications. The ground facilities are comprised of two major components: (1) The Base Research Station (BRS), a LaRC laboratory facility for system development, testing and data analysis, and (2) The Mobile Operations Station (MOS), a self-contained, motorized vehicle serving as a mobile research command/operations center, functionally equivalent to the BRS, capable of deployment to remote sites for supporting flight tests. The third piece of the testbed is the test facility itself. Research flights carried out by the AirSTAR team are conducted at NASA Wallops Flight Facility (WFF) on the Eastern Shore of Virginia. The UAV Island runway is a 50 x 1500 paved runway that lies within restricted airspace at Wallops Flight Facility. The

  7. Advancements of in-flight mass moment of inertia and structural deflection algorithms for satellite attitude simulators

    Science.gov (United States)

    Wright, Jonathan W.

    Experimental satellite attitude simulators have long been used to test and analyze control algorithms in order to drive down risk before implementation on an operational satellite. Ideally, the dynamic response of a terrestrial-based experimental satellite attitude simulator would be similar to that of an on-orbit satellite. Unfortunately, gravitational disturbance torques and poorly characterized moments of inertia introduce uncertainty into the system dynamics leading to questionable attitude control algorithm experimental results. This research consists of three distinct, but related contributions to the field of developing robust satellite attitude simulators. In the first part of this research, existing approaches to estimate mass moments and products of inertia are evaluated followed by a proposition and evaluation of a new approach that increases both the accuracy and precision of these estimates using typical on-board satellite sensors. Next, in order to better simulate the micro-torque environment of space, a new approach to mass balancing satellite attitude simulator is presented, experimentally evaluated, and verified. Finally, in the third area of research, we capitalize on the platform improvements to analyze a control moment gyroscope (CMG) singularity avoidance steering law. Several successful experiments were conducted with the CMG array at near-singular configurations. An evaluation process was implemented to verify that the platform remained near the desired test momentum, showing that the first two components of this research were effective in allowing us to conduct singularity avoidance experiments in a representative space-like test environment.

  8. Clear Skies and Grey Areas: Flight Attendants’ Secondhand Smoke Exposure and Attitudes toward Smoke-Free Policy 25 Years since Smoking was Banned on Airplanes

    Directory of Open Access Journals (Sweden)

    Frances A. Stillman

    2015-06-01

    Full Text Available Our objective was to provide descriptive data on flight attendant secondhand smoke (SHS exposure in the work environment, and to examine attitudes toward SHS exposure, personal health, and smoke-free policy in the workplace and public places. Flight attendants completed a web-based survey of self-reported SHS exposure and air quality in the work environment. We assessed the frequency and duration of SHS exposure in distinct areas of the workplace, attitudes toward SHS exposure and its health effects, and attitudes toward smoke-free policy in the workplace as well as general public places. A total of 723 flight attendants participated in the survey, and 591 responded to all survey questions. The mean level of exposure per flight attendant over the past month was 249 min. The majority of participants reported being exposed to SHS always/often in outdoor areas of an airport (57.7%. Participants who worked before the in-flight smoking ban (n = 240 were more likely to support further smoking policies in airports compared to participants who were employed after the ban (n = 346 (76.7% versus 60.4%, p-value < 0.01. Flight attendants are still being exposed to SHS in the workplace, sometimes at concerning levels during the non-flight portions of their travel. Flight attendants favor smoke-free policies and want to see further restrictions in airports and public places.

  9. The flying classroom - a cost effective integrated approach to learning and teaching flight dynamics

    Science.gov (United States)

    Bromfield, Michael A.; Belberov, Aleksandar

    2017-11-01

    In the UK, the Royal Aeronautical Society recommends the inclusion of practical flight exercises for accredited undergraduate aerospace engineering programmes to enhance learning and student experience. The majority of academic institutions teaching aerospace in the UK separate the theory and practice of flight dynamics with students attending a series of lectures supplemented by an intensive one-day flight exercise. Performance and/or handling qualities flight tests are performed in a dedicated aircraft fitted with specialist equipment for the recording and presentation of flight data. This paper describes an innovative approach to better integrate theory and practice and the use of portable Commercial-off-The-Shelf (COTS) technologies to enable a range of standard, unmodified aircraft to be used. The integration of theory and practice has enriched learning and teaching, improved coursework grades and the student experience. The use of COTS and unmodified aircraft has reduced costs and enabled increased student participation.

  10. Verification of the Solar Dynamics Observatory High Gain Antenna Pointing Algorithm Using Flight Data

    Science.gov (United States)

    Bourkland, Kristin L.; Liu, Kuo-Chia

    2011-01-01

    The Solar Dynamics Observatory (SDO) is a NASA spacecraft designed to study the Sun. It was launched on February 11, 2010 into a geosynchronous orbit, and uses a suite of attitude sensors and actuators to finely point the spacecraft at the Sun. SDO has three science instruments: the Atmospheric Imaging Assembly (AIA), the Helioseismic and Magnetic Imager (HMI), and the Extreme Ultraviolet Variability Experiment (EVE). SDO uses two High Gain Antennas (HGAs) to send science data to a dedicated ground station in White Sands, New Mexico. In order to meet the science data capture budget, the HGAs must be able to transmit data to the ground for a very large percentage of the time. Each HGA is a dual-axis antenna driven by stepper motors. Both antennas transmit data at all times, but only a single antenna is required in order to meet the transmission rate requirement. For portions of the year, one antenna or the other has an unobstructed view of the White Sands ground station. During other periods, however, the view from both antennas to the Earth is blocked for different portions of the day. During these times of blockage, the two HGAs take turns pointing to White Sands, with the other antenna pointing out to space. The HGAs handover White Sands transmission responsibilities to the unblocked antenna. There are two handover seasons per year, each lasting about 72 days, where the antennas hand off control every twelve hours. The non-tracking antenna slews back to the ground station by following a ground commanded trajectory and arrives approximately 5 minutes before the formerly tracking antenna slews away to point out into space. The SDO Attitude Control System (ACS) runs at 5 Hz, and the HGA Gimbal Control Electronics (GCE) run at 200 Hz. There are 40 opportunities for the gimbals to step each ACS cycle, with a hardware limitation of no more than one step every three GCE cycles. The ACS calculates the desired gimbal motion for tracking the ground station or for slewing

  11. Implementation and Test of the Automatic Flight Dynamics Operations for Geostationary Satellite Mission

    Directory of Open Access Journals (Sweden)

    Sangwook Park

    2009-12-01

    Full Text Available This paper describes the Flight Dynamics Automation (FDA system for COMS Flight Dynamics System (FDS and its test result in terms of the performance of the automation jobs. FDA controls the flight dynamics functions such as orbit determination, orbit prediction, event prediction, and fuel accounting. The designed FDA is independent from the specific characteristics which are defined by spacecraft manufacturer or specific satellite missions. Therefore, FDA could easily links its autonomous job control functions to any satellite mission control system with some interface modification. By adding autonomous system along with flight dynamics system, it decreases the operator’s tedious and repeated jobs but increase the usability and reliability of the system. Therefore, FDA is used to improve the completeness of whole mission control system’s quality. The FDA is applied to the real flight dynamics system of a geostationary satellite, COMS and the experimental test is performed. The experimental result shows the stability and reliability of the mission control operations through the automatic job control.

  12. Analytical, Computational Fluid Dynamics and Flight Dynamics of Coandă MAV

    Science.gov (United States)

    Djojodihardjo, H.; Ahmed, RI

    2016-11-01

    The paper establishes the basic working relationships among various relevant variables and parameters governing the aerodynamics forces and performance measures of Coandă MAV in hover and translatory motion. With such motivation, capitalizing on the basic fundamental principles, the Fluid Dynamics and Flight Mechanics of semi-spherical Coandă MAV configurations are revisited and analyzed as a baseline. To gain better understanding on the principle of Coandă MAV lift generation, a mathematical model for a spherical Coandă MAV is developed and analyzed from first physical principles. To gain further insight into the prevailing flow field around a Coandă MAV, as well as to verify the theoretical prediction presented in the work, a computational fluid dynamic CFD simulation for a Coandă MAV generic model are elaborated using commercial software FLUENT®. In addition, the equation of motion for translatory motion of Coandă MAV is elaborated. The mathematical model and derived performance measures are shown to be capable in describing the physical phenomena of the flow field of the semi-spherical Coandă MAV. The relationships between the relevant parameters of the mathematical model of the Coandă MAV to the forces acting on it are elaborated subsequently.

  13. Experimental Analysis of the Vorticity and Turbulent Flow Dynamics of a Pitching Airfoil at Realistic Flight Conditions

    National Research Council Canada - National Science Library

    Bowersox, Rodney D; Sahoo, Dipankar

    2007-01-01

    The primary objective of this research proposal was improved understanding of the fundamental vorticity and turbulent flow physics for a dynamically stalling airfoil at realistic helicopter flight conditions...

  14. NASA Armstrong Flight Research Center Dynamics and Controls Branch

    Science.gov (United States)

    Jacobson, Steve

    2015-01-01

    NASA Armstrong continues its legacy of exciting work in the area of Dynamics and Control of advanced vehicle concepts. This presentation describes Armstrongs research in control of flexible structures, peak seeking control and adaptive control in the Spring of 2015.

  15. Modelling the impact of beliefs and communication on attitude dynamics : a cognitive agent-based approach

    OpenAIRE

    Brousmiche, Kei-Leo; Kant, Jean-Daniel; Sabouret, Nicolas; Fournier, Stephane; Prenot-Guinard, Francois

    2014-01-01

    In the context of military training for stabilization operation of a crisis zone with civilian population, understanding the formation of attitude and its dynamics is a key issue. This paper presents a multi-agent model for simulating attitude formation and change based on individual’s perception of information and its diffusion through communication. We represent the attitude as object-evaluation associations of varying strength proposed by Fazio [1]. Individuals observe military operations....

  16. Development of an Integrated Nonlinear Aeroservoelastic Flight Dynamic Model of the NASA Generic Transport Model

    Science.gov (United States)

    Nguyen, Nhan; Ting, Eric

    2018-01-01

    This paper describes a recent development of an integrated fully coupled aeroservoelastic flight dynamic model of the NASA Generic Transport Model (GTM). The integrated model couples nonlinear flight dynamics to a nonlinear aeroelastic model of the GTM. The nonlinearity includes the coupling of the rigid-body aircraft states in the partial derivatives of the aeroelastic angle of attack. Aeroservoelastic modeling of the control surfaces which are modeled by the Variable Camber Continuous Trailing Edge Flap is also conducted. The R.T. Jones' method is implemented to approximate unsteady aerodynamics. Simulations of the GTM are conducted with simulated continuous and discrete gust loads..

  17. Motivational Dynamics in the Development of Career Attitudes among Adolescents

    Science.gov (United States)

    Janeiro, Isabel Nunes

    2010-01-01

    Super (1990) proposed that the psychological determinants of career development attitudes are time perspective, self-esteem, and causal attributions. The present study analyzed the effects of these determinants on the career development attitudes of 320 students from grade 9 and 300 students from grade 12. The analysis of the data using structural…

  18. Tether dynamics and control results for tethered satellite system's initial flight

    Science.gov (United States)

    Chapel, Jim D.; Flanders, Howard

    The recent Tethered Satellite System-1 (TSS-1) mission has provided a wealth of data concerning the dynamics of tethered systems in space and has demonstrated the effectiveness of operational techniques designed to control these dynamics. In this paper, we review control techniques developed for managing tether dynamics, and discuss the results of using these techniques for the Tethered Satellite System's maiden flight on STS-46. In particular, the flight results of controlling libration dynamics, string dynamics, and slack tether are presented. These results show that tether dynamics can be safely managed. The overall stability of the system was found to be surprisingly good even at relatively short tether lengths. In fact, the system operated in passive mode at a tether length of 256 meters for over 9 hours. Only monitoring of the system was required during this time. Although flight anomalies prevented the planned deployment to 20 km, the extended operations at shorter tether lengths have proven the viability of using tethers in space. These results should prove invaluable in preparing for future missions with tethered objects in space.

  19. Error compensation of single-antenna attitude determination using GNSS for Low-dynamic applications

    Science.gov (United States)

    Chen, Wen; Yu, Chao; Cai, Miaomiao

    2017-04-01

    GNSS-based single-antenna pseudo-attitude determination method has attracted more and more attention from the field of high-dynamic navigation due to its low cost, low system complexity, and no temporal accumulated errors. Related researches indicate that this method can be an important complement or even an alternative to the traditional sensors for general accuracy requirement (such as small UAV navigation). The application of single-antenna attitude determining method to low-dynamic carrier has just started. Different from the traditional multi-antenna attitude measurement technique, the pseudo-attitude attitude determination method calculates the rotation angle of the carrier trajectory relative to the earth. Thus it inevitably contains some deviations comparing with the real attitude angle. In low-dynamic application, these deviations are particularly noticeable, which may not be ignored. The causes of the deviations can be roughly classified into three categories, including the measurement error, the offset error, and the lateral error. Empirical correction strategies for the formal two errors have been promoted in previous study, but lack of theoretical support. In this paper, we will provide quantitative description of the three type of errors and discuss the related error compensation methods. Vehicle and shipborne experiments were carried out to verify the feasibility of the proposed correction methods. Keywords: Error compensation; Single-antenna; GNSS; Attitude determination; Low-dynamic

  20. Pilot dynamics for instrument approach tasks: Full panel multiloop and flight director operations

    Science.gov (United States)

    Weir, D. H.; Mcruer, D. T.

    1972-01-01

    Measurements and interpretations of single and mutiloop pilot response properties during simulated instrument approach are presented. Pilot subjects flew Category 2-like ILS approaches in a fixed base DC-8 simulaton. A conventional instrument panel and controls were used, with simulated vertical gust and glide slope beam bend forcing functions. Reduced and interpreted pilot describing functions and remmant are given for pitch attitude, flight director, and multiloop (longitudinal) control tasks. The response data are correlated with simultaneously recorded eye scanning statistics, previously reported in NASA CR-1535. The resulting combined response and scanning data and their interpretations provide a basis for validating and extending the theory of manual control displays.

  1. Optimal Attitude Estimation and Filtering Without Using Local Coordinates Part I: Uncontrolled and Deterministic Attitude Dynamics

    OpenAIRE

    Sanyal, Amit K.

    2005-01-01

    There are several attitude estimation algorithms in existence, all of which use local coordinate representations for the group of rigid body orientations. All local coordinate representations of the group of orientations have associated problems. While minimal coordinate representations exhibit kinematic singularities for large rotations, the quaternion representation requires satisfaction of an extra constraint. This paper treats the attitude estimation and filtering problem as an optimizati...

  2. Spinning Flight Dynamics of Frisbees, Boomerangs, Samaras, and Skipping Stones

    CERN Document Server

    Lorenz, Ralph D

    2006-01-01

    More frisbees are sold each year than baseballs, basketballs, and footballs combined. Yet these familiar flying objects have subtle and clever aerodynamic and gyrodynamic properties which are only recently being documented by wind tunnel and other studies. In common with other rotating bodies discussed in this readily accessible book, they are typically not treated in textbooks of aeronautics and the literature is scattered in a variety of places. This book develops the theme of disc-wings and spinning aerospace vehicles in parallel. Many readers will have enjoyed these vehicles and their dynamics in recreational settings, so this book will be of wide interest. In addition to spinning objects of various shapes, several exotic manned aircraft with disc platforms have been proposed and prototypes built - these include a Nazi ‘secret weapon’ and the De Havilland Avrocar, also discussed in the book. Boomerangs represent another category of spinning aerodynamic body whose behavior can only be understood by cou...

  3. Mechanics of Flapping Flight: Analytical Formulations of Unsteady Aerodynamics, Kinematic Optimization, Flight Dynamics, and Control

    Science.gov (United States)

    Taneja, Jayant Kumar

    Electricity is an indispensable commodity to modern society, yet it is delivered via a grid architecture that remains largely unchanged over the past century. A host of factors are conspiring to topple this dated yet venerated design: developments in renewable electricity generation technology, policies to reduce greenhouse gas emissions, and advances in information technology for managing energy systems. Modern electric grids are emerging as complex distributed systems in which a portfolio of power generation resources, often incorporating fluctuating renewable resources such as wind and solar, must be managed dynamically to meet uncontrolled, time-varying demand. Uncertainty in both supply and demand makes control of modern electric grids fundamentally more challenging, and growing portfolios of renewables exacerbate the challenge. We study three electricity grids: the state of California, the province of Ontario, and the country of Germany. To understand the effects of increasing renewables, we develop a methodology to scale renewables penetration. Analyzing these grids yields key insights about rigid limits to renewables penetration and their implications in meeting long-term emissions targets. We argue that to achieve deep penetration of renewables, the operational model of the grid must be inverted, changing the paradigm from load-following supplies to supply-following loads. To alleviate the challenge of supply-demand matching on deeply renewable grids, we first examine well-known techniques, including altering management of existing supply resources, employing utility-scale energy storage, targeting energy efficiency improvements, and exercising basic demand-side management. Then, we create several instantiations of supply-following loads -- including refrigerators, heating and cooling systems, and laptop computers -- by employing a combination of sensor networks, advanced control techniques, and enhanced energy storage. We examine the capacity of each load

  4. Modeling the angular motion dynamics of spacecraft with a magnetic attitude control system based on experimental studies and dynamic similarity

    Science.gov (United States)

    Kulkov, V. M.; Medvedskii, A. L.; Terentyev, V. V.; Firsyuk, S. O.; Shemyakov, A. O.

    2017-12-01

    The problem of spacecraft attitude control using electromagnetic systems interacting with the Earth's magnetic field is considered. A set of dimensionless parameters has been formed to investigate the spacecraft orientation regimes based on dynamically similar models. The results of experimental studies of small spacecraft with a magnetic attitude control system can be extrapolated to the in-orbit spacecraft motion control regimes by using the methods of the dimensional and similarity theory.

  5. IRVE-II Post-Flight Trajectory Reconstruction

    Science.gov (United States)

    O'Keefe, Stephen A.; Bose, David M.

    2010-01-01

    NASA s Inflatable Re-entry Vehicle Experiment (IRVE) II successfully demonstrated an inflatable aerodynamic decelerator after being launched aboard a sounding rocket from Wallops Flight Facility (WFF). Preliminary day of flight data compared well with pre-flight Monte Carlo analysis, and a more complete trajectory reconstruction performed with an Extended Kalman Filter (EKF) approach followed. The reconstructed trajectory and comparisons to an attitude solution provided by NASA Sounding Rocket Operations Contract (NSROC) personnel at WFF are presented. Additional comparisons are made between the reconstructed trajectory and pre and post-flight Monte Carlo trajectory predictions. Alternative observations of the trajectory are summarized which leverage flight accelerometer measurements, the pre-flight aerodynamic database, and on-board flight video. Finally, analysis of the payload separation and aeroshell deployment events are presented. The flight trajectory is reconstructed to fidelity sufficient to assess overall project objectives related to flight dynamics and overall, IRVE-II flight dynamics are in line with expectations

  6. Indeterminacy of drag exerted on an arrow in free flight: arrow attitude and laminar-turbulent transition

    Science.gov (United States)

    Miyazaki, T.; Matsumoto, T.; Ando, R.; Ortiz, J.; Sugiura, H.

    2017-11-01

    The aerodynamic properties of an arrow (A/C/E; Easton) were investigated in an extension of our previous work, in which the laminar-turbulent transition of the boundary layer on the arrow shaft was found to take place in the Re number range of 1.2 × 104 aligned with the flow, the boundary layer remains laminar for Re < 1.5 × 104, and the drag coefficient is approximately 1.5 for 1.0 × 104 < Re < 1.5 × 104. If the arrow has an angle of attack of 0.75 ° with the flow, the transition to turbulence takes place at approximately Re = 1.1 × 104, and the drag coefficient increases to approximately 3.1. In addition, free flight experiments are performed. The arrow’s velocity and angular velocity are recorded using five high-speed video cameras. By analysing the recorded images, we obtain the initial and final velocities from which the drag coefficient is determined. The trajectory and attitude of the arrow in free flight are computed numerically by integrating the equations of motion for a rigid body using the initial data obtained from the video images. The laminar-turbulent transition of the boundary layer is shown to take place, if the maximum angle of attack exceeds about 0.4° at Re = 1.75 × 104. The crucial influence of the initial angular velocity on the angle of attack is also examined.

  7. Computer program for post-flight evaluation of the control surface response for an attitude controlled missile

    Science.gov (United States)

    Knauber, R. N.

    1982-01-01

    A FORTRAN IV coded computer program is presented for post-flight analysis of a missile's control surface response. It includes preprocessing of digitized telemetry data for time lags, biases, non-linear calibration changes and filtering. Measurements include autopilot attitude rate and displacement gyro output and four control surface deflections. Simple first order lags are assumed for the pitch, yaw and roll axes of control. Each actuator is also assumed to be represented by a first order lag. Mixing of pitch, yaw and roll commands to four control surfaces is assumed. A pseudo-inverse technique is used to obtain the pitch, yaw and roll components from the four measured deflections. This program has been used for over 10 years on the NASA/SCOUT launch vehicle for post-flight analysis and was helpful in detecting incipient actuator stall due to excessive hinge moments. The program is currently set up for a CDC CYBER 175 computer system. It requires 34K words of memory and contains 675 cards. A sample problem presented herein including the optional plotting requires eleven (11) seconds of central processor time.

  8. Clear Skies and Grey Areas: Flight Attendants' Secondhand Smoke Exposure and Attitudes toward Smoke-Free Policy 25 Years since Smoking was Banned on Airplanes.

    Science.gov (United States)

    Stillman, Frances A; Soong, Andrea; Zheng, Laura Y; Navas-Acien, Ana

    2015-06-04

    Our objective was to provide descriptive data on flight attendant secondhand smoke (SHS) exposure in the work environment, and to examine attitudes toward SHS exposure, personal health, and smoke-free policy in the workplace and public places. Flight attendants completed a web-based survey of self-reported SHS exposure and air quality in the work environment. We assessed the frequency and duration of SHS exposure in distinct areas of the workplace, attitudes toward SHS exposure and its health effects, and attitudes toward smoke-free policy in the workplace as well as general public places. A total of 723 flight attendants participated in the survey, and 591 responded to all survey questions. The mean level of exposure per flight attendant over the past month was 249 min. The majority of participants reported being exposed to SHS always/often in outdoor areas of an airport (57.7%). Participants who worked before the in-flight smoking ban (n=240) were more likely to support further smoking policies in airports compared to participants who were employed after the ban (n=346) (76.7% versus 60.4%, p-valuesmoke-free policies and want to see further restrictions in airports and public places.

  9. Flight Dynamic Simulation of Fighter In the Asymmetric External Store Release Process

    Science.gov (United States)

    Safi’i, Imam; Arifianto, Ony; Nurohman, Chandra

    2018-04-01

    In the fighter design, it is important to evaluate and analyze the flight dynamic of the aircraft earlier in the development process. One of the case is the dynamics of external store release process. A simulation tool can be used to analyze the fighter/external store system’s dynamics in the preliminary design stage. This paper reports the flight dynamics of Jet Fighter Experiment (JF-1 E) in asymmetric Advance Medium Range Air to Air Missile (AMRAAM) release process through simulations. The JF-1 E and AIM 120 AMRAAAM models are built by using Advanced Aircraft Analysis (AAA) and Missile Datcom software. By using these softwares, the aerodynamic stability and control derivatives can be obtained and used to model the dynamic characteristic of the fighter and the external store. The dynamic system is modeled by using MATLAB/Simulink software. By using this software, both the fighter/external store integration and the external store release process is simulated, and the dynamic of the system can be analyzed.

  10. Advanced Modeling and Uncertainty Quantification for Flight Dynamics; Interim Results and Challenges

    Science.gov (United States)

    Hyde, David C.; Shweyk, Kamal M.; Brown, Frank; Shah, Gautam

    2014-01-01

    As part of the NASA Vehicle Systems Safety Technologies (VSST), Assuring Safe and Effective Aircraft Control Under Hazardous Conditions (Technical Challenge #3), an effort is underway within Boeing Research and Technology (BR&T) to address Advanced Modeling and Uncertainty Quantification for Flight Dynamics (VSST1-7). The scope of the effort is to develop and evaluate advanced multidisciplinary flight dynamics modeling techniques, including integrated uncertainties, to facilitate higher fidelity response characterization of current and future aircraft configurations approaching and during loss-of-control conditions. This approach is to incorporate multiple flight dynamics modeling methods for aerodynamics, structures, and propulsion, including experimental, computational, and analytical. Also to be included are techniques for data integration and uncertainty characterization and quantification. This research shall introduce new and updated multidisciplinary modeling and simulation technologies designed to improve the ability to characterize airplane response in off-nominal flight conditions. The research shall also introduce new techniques for uncertainty modeling that will provide a unified database model comprised of multiple sources, as well as an uncertainty bounds database for each data source such that a full vehicle uncertainty analysis is possible even when approaching or beyond Loss of Control boundaries. Methodologies developed as part of this research shall be instrumental in predicting and mitigating loss of control precursors and events directly linked to causal and contributing factors, such as stall, failures, damage, or icing. The tasks will include utilizing the BR&T Water Tunnel to collect static and dynamic data to be compared to the GTM extended WT database, characterizing flight dynamics in off-nominal conditions, developing tools for structural load estimation under dynamic conditions, devising methods for integrating various modeling elements

  11. Flight Loads Prediction of High Aspect Ratio Wing Aircraft Using Multibody Dynamics

    Directory of Open Access Journals (Sweden)

    Michele Castellani

    2016-01-01

    Full Text Available A framework based on multibody dynamics has been developed for the static and dynamic aeroelastic analyses of flexible high aspect ratio wing aircraft subject to structural geometric nonlinearities. Multibody dynamics allows kinematic nonlinearities and nonlinear relationships in the forces definition and is an efficient and promising methodology to model high aspect ratio wings, which are known to be prone to structural nonlinear effects because of the high deflections in flight. The multibody dynamics framework developed employs quasi-steady aerodynamics strip theory and discretizes the wing as a series of rigid bodies interconnected by beam elements, representative of the stiffness distribution, which can undergo arbitrarily large displacements and rotations. The method is applied to a flexible high aspect ratio wing commercial aircraft and both trim and gust response analyses are performed in order to calculate flight loads. These results are then compared to those obtained with the standard linear aeroelastic approach provided by the Finite Element Solver Nastran. Nonlinear effects come into play mainly because of the need of taking into account the large deflections of the wing for flight loads computation and of considering the aerodynamic forces as follower forces.

  12. Vibration detection with 100 Hz GPS PVAT during a dynamic flight

    Science.gov (United States)

    Bischof, Christian; Schön, Steffen

    2017-06-01

    This investigation gives insights into real 100 Hz GPS velocity and acceleration estimates from a position, velocity, acceleration and time (PVAT) extended Kalman filter (EKF) during a highly dynamic flight trial with a Dornier Do 128-6 aircraft. We investigated the accelerations during take-off, landing and wing shaking manoeuvres in order to compare the vibration behaviour of the given aircraft determined by means of GPS against an onboard IMU. We found that 100 Hz GPS acceleration is useful for characterising vibrations and giving valuable insights during highly dynamic flights. Potential latency of 0.12 s and amplitude misestimation of up to 80% w.r.t. the reference amplitude occur that should be determined beforehand in order to correctly interpret the results.

  13. On the internal stability of non-linear dynamic inversion: application to flight control

    Czech Academy of Sciences Publication Activity Database

    Alam, M.; Čelikovský, Sergej

    2017-01-01

    Roč. 11, č. 12 (2017), s. 1849-1861 ISSN 1751-8644 R&D Projects: GA ČR(CZ) GA17-04682S Institutional support: RVO:67985556 Keywords : flight control * non-linear dynamic inversion * stability Subject RIV: BC - Control Systems Theory OBOR OECD: Automation and control systems Impact factor: 2.536, year: 2016 http://library.utia.cas.cz/separaty/2017/TR/celikovsky-0476150.pdf

  14. Cassini Spacecraft In-Flight Swap to Backup Attitude Control Thrusters

    Science.gov (United States)

    Bates, David M.

    2010-01-01

    NASA's Cassini Spacecraft, launched on October 15th, 1997 and arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. In order to meet the challenging attitude control and navigation requirements of the orbit profile at Saturn, Cassini is equipped with a monopropellant thruster based Reaction Control System (RCS), a bipropellant Main Engine Assembly (MEA) and a Reaction Wheel Assembly (RWA). In 2008, after 11 years of reliable service, several RCS thrusters began to show signs of end of life degradation, which led the operations team to successfully perform the swap to the backup RCS system, the details and challenges of which are described in this paper. With some modifications, it is hoped that similar techniques and design strategies could be used to benefit other spacecraft.

  15. Investigating On-Orbit Attitude Determination Anomalies for the Solar Dynamics Observatory Mission

    Science.gov (United States)

    Vess, Melissa F.; Starin, Scott R.; Chia-Kuo, Alice Liu

    2011-01-01

    The Solar Dynamics Observatory (SDO) was launched on February 11, 2010 from Kennedy Space Center on an Atlas V launch vehicle into a geosynchronous transfer orbit. SDO carries a suite of three scientific instruments, whose observations are intended to promote a more complete understanding of the Sun and its effects on the Earth's environment. After a successful launch, separation, and initial Sun acquisition, the launch and flight operations teams dove into a commissioning campaign that included, among other things, checkout and calibration of the fine attitude sensors and checkout of the Kalman filter (KF) and the spacecraft s inertial pointing and science control modes. In addition, initial calibration of the science instruments was also accomplished. During that process of KF and controller checkout, several interesting observations were noticed and investigated. The SDO fine attitude sensors consist of one Adcole Digital Sun Sensor (DSS), two Galileo Avionica (GA) quaternion-output Star Trackers (STs), and three Kearfott Two-Axis Rate Assemblies (hereafter called inertial reference units, or IRUs). Initial checkout of the fine attitude sensors indicated that all sensors appeared to be functioning properly. Initial calibration maneuvers were planned and executed to update scale factors, drift rate biases, and alignments of the IRUs. After updating the IRU parameters, the KF was initialized and quickly reached convergence. Over the next few hours, it became apparent that there was an oscillation in the sensor residuals and the KF estimation of the IRU bias. A concentrated investigation ensued to determine the cause of the oscillations, their effect on mission requirements, and how to mitigate them. The ensuing analysis determined that the oscillations seen were, in fact, due to an oscillation in the IRU biases. The low frequencies of the oscillations passed through the KF, were well within the controller bandwidth, and therefore the spacecraft was actually

  16. Adaptive Estimation and Heuristic Optimization of Nonlinear Spacecraft Attitude Dynamics

    Science.gov (United States)

    2016-09-15

    Biology, Control and Artificial Intelligence , MIT Press, Cambridge, MA, USA, 1992. 177 [89] Thompson, R. E., Colombi, J. M., Black, J. T., and Ayres...utilized for parameter and state estimates. MMAE algorithms involve constructing a bank of recursive estimators, each assuming a different hypothesis for...this research, MMAE routines employing parallel banks of unscented attitude filters are applied to analytical models of spacecraft with time- varying

  17. Dynamic Exposure to Alcohol Advertising in a Sports Context Influences Implicit Attitudes.

    Science.gov (United States)

    Zerhouni, Oulmann; Bègue, Laurent; Duke, Aaron A; Flaudias, Valentin

    2016-02-01

    Experimental studies investigating the impact of advertising with ecological stimuli on alcohol-related cognition are scarce. This research investigated the cognitive processes involved in learning implicit attitudes toward alcohol after incidental exposure to alcohol advertisements presented in a dynamic context. We hypothesized that incidental exposure to a specific alcohol brand would lead to heightened positive implicit attitudes toward alcohol due to a mere exposure effect. In total, 108 participants were randomly exposed to dynamic sporting events excerpts with and without advertising for a specific brand of alcohol, after completing self-reported measures of alcohol-related expectancies, alcohol consumption, and attitudes toward sport. Participants then completed a lexical decision task and an affective priming task. We showed that participants were faster to detect brand name after being exposed to advertising during a sports game, and that implicit attitudes of participants toward the brand were more positive after they were exposed to advertising, even when alcohol usage patterns were controlled for. Incidental exposure to alcohol sponsorship in sport events impacts implicit attitudes toward the advertised brand and alcohol in general. The effect of incidental advertising on implicit attitudes is also likely to be due to a mere exposure effect. However, further studies should address this point specifically. Copyright © 2016 by the Research Society on Alcoholism.

  18. RHAGOLETIS COMPLETA (DIPTERA; TEPHRITIDAE) DISTRIBUTION, FLIGHT DYNAMICS AND INFLUENCE ON WALNUT KERNEL QUALITY IN THE CONTINENTAL CROATIA

    OpenAIRE

    Božena Barić; Ivana Pajač Živković; Dinka Matošević; Milorad Šubić; Erzsébet Voigt; Miklós Tóth

    2015-01-01

    Walnut husk fly (WHF), Rhagoletis completa Cresson 1929 is an invasive species spreading quickly and damaging walnuts in Croatia and neighbouring countries. We researched distribution of this pest in the continental part of Croatia, flight dynamics in Međimurje County and its influence on quality of walnut kernels. CSALOMON®PALz traps were used for monitoring the spread and flight dynamics of R. completa. Weight and the protein content of kernels and the presence of mycotoxin contamination we...

  19. AirSTAR: A UAV Platform for Flight Dynamics and Control System Testing

    Science.gov (United States)

    Jordan, Thomas L.; Foster, John V.; Bailey, Roger M.; Belcastro, Christine M.

    2006-01-01

    As part of the NASA Aviation Safety Program at Langley Research Center, a dynamically scaled unmanned aerial vehicle (UAV) and associated ground based control system are being developed to investigate dynamics modeling and control of large transport vehicles in upset conditions. The UAV is a 5.5% (seven foot wingspan), twin turbine, generic transport aircraft with a sophisticated instrumentation and telemetry package. A ground based, real-time control system is located inside an operations vehicle for the research pilot and associated support personnel. The telemetry system supports over 70 channels of data plus video for the downlink and 30 channels for the control uplink. Data rates are in excess of 200 Hz. Dynamic scaling of the UAV, which includes dimensional, weight, inertial, actuation, and control system scaling, is required so that the sub-scale vehicle will realistically simulate the flight characteristics of the full-scale aircraft. This testbed will be utilized to validate modeling methods, flight dynamics characteristics, and control system designs for large transport aircraft, with the end goal being the development of technologies to reduce the fatal accident rate due to loss-of-control.

  20. Lateral dynamic flight stability of a model hoverfly in normal and inclined stroke-plane hovering

    International Nuclear Information System (INIS)

    Xu, Na; Sun, Mao

    2014-01-01

    Many insects hover with their wings beating in a horizontal plane (‘normal hovering’), while some insects, e.g., hoverflies and dragonflies, hover with inclined stroke-planes. Here, we investigate the lateral dynamic flight stability of a hovering model hoverfly. The aerodynamic derivatives are computed using the method of computational fluid dynamics, and the equations of motion are solved by the techniques of eigenvalue and eigenvector analysis. The following is shown: The flight of the insect is unstable at normal hovering (stroke-plane angle equals 0) and the instability becomes weaker as the stroke-plane angle increases; the flight becomes stable at a relatively large stroke-plane angle (larger than about 24°). As previously shown, the instability at normal hovering is due to a positive roll-moment/side-velocity derivative produced by the ‘changing-LEV-axial-velocity’ effect. When the stroke-plane angle increases, the wings bend toward the back of the body, and the ‘changing-LEV-axial-velocity’ effect decreases; in addition, another effect, called the ‘changing-relative-velocity’ effect (the ‘lateral wind’, which is due to the side motion of the insect, changes the relative velocity of its wings), becomes increasingly stronger. This causes the roll-moment/side-velocity derivative to first decrease and then become negative, resulting in the above change in stability as a function of the stroke-plane angle. (paper)

  1. Attitude dynamics and control of spacecraft with a partially filled liquid tank and flexible panels

    Science.gov (United States)

    Liu, Feng; Yue, Baozeng; Zhao, Liangyu

    2018-02-01

    A liquid-filled flexible spacecraft is essentially a time-variant fully-coupled system, whose dynamics characteristics are closely associated with its motion features. This paper focuses on the mathematical modelling and attitude control of the spacecraft coupled with fuel sloshing dynamics and flexible solar panels vibration. The slosh motion is represented by a spherical pendulum, whose motion description method is improved by using split variable operation. Benefiting from this improvement, the nonlinear lateral sloshing and the rotary sloshing as well as the rigid motion of a liquid respect to the spacecraft can be approximately described. The assumed modes discretization method has been adopted to approximate the elastic displacements of the attached panels, and the coupled dynamics is derived by using the Lagrangian formulation. A variable substitution method is proposed to obtain the apparently-uncoupled mathematical model of the rigid-flexible-liquid spacecraft. After linearization, this model can be directly used for designing Lyapunov output-feedback attitude controller (OFAC). With only torque actuators, and attitude and rate sensors installed, this kind of attitude controller, as simulation results show, is capable of not only bringing the spacecraft to the desired orientation, but also suppressing the effect of flex and slosh on the attitude motion of the spacecraft.

  2. Comparison of Controller and Flight Deck Algorithm Performance During Interval Management with Dynamic Arrival Trees (STARS)

    Science.gov (United States)

    Battiste, Vernol; Lawton, George; Lachter, Joel; Brandt, Summer; Koteskey, Robert; Dao, Arik-Quang; Kraut, Josh; Ligda, Sarah; Johnson, Walter W.

    2012-01-01

    Managing the interval between arrival aircraft is a major part of the en route and TRACON controller s job. In an effort to reduce controller workload and low altitude vectoring, algorithms have been developed to allow pilots to take responsibility for, achieve and maintain proper spacing. Additionally, algorithms have been developed to create dynamic weather-free arrival routes in the presence of convective weather. In a recent study we examined an algorithm to handle dynamic re-routing in the presence of convective weather and two distinct spacing algorithms. The spacing algorithms originated from different core algorithms; both were enhanced with trajectory intent data for the study. These two algorithms were used simultaneously in a human-in-the-loop (HITL) simulation where pilots performed weather-impacted arrival operations into Louisville International Airport while also performing interval management (IM) on some trials. The controllers retained responsibility for separation and for managing the en route airspace and some trials managing IM. The goal was a stress test of dynamic arrival algorithms with ground and airborne spacing concepts. The flight deck spacing algorithms or controller managed spacing not only had to be robust to the dynamic nature of aircraft re-routing around weather but also had to be compatible with two alternative algorithms for achieving the spacing goal. Flight deck interval management spacing in this simulation provided a clear reduction in controller workload relative to when controllers were responsible for spacing the aircraft. At the same time, spacing was much less variable with the flight deck automated spacing. Even though the approaches taken by the two spacing algorithms to achieve the interval management goals were slightly different they seem to be simpatico in achieving the interval management goal of 130 sec by the TRACON boundary.

  3. Attitude dynamics and control of a spacecraft using shifting mass distribution

    Science.gov (United States)

    Ahn, Young Tae

    Spacecraft need specific attitude control methods that depend on the mission type or special tasks. The dynamics and the attitude control of a spacecraft with a shifting mass distribution within the system are examined. The behavior and use of conventional attitude control actuators are widely developed and performing at the present time. However, the advantage of a shifting mass distribution concept can complement spacecraft attitude control, save mass, and extend a satellite's life. This can be adopted in practice by moving mass from one tank to another, similar to what an airplane does to balance weight. Using this shifting mass distribution concept, in conjunction with other attitude control devices, can augment the three-axis attitude control process. Shifting mass involves changing the center-of-mass of the system, and/or changing the moments of inertia of the system, which then ultimately can change the attitude behavior of the system. This dissertation consists of two parts. First, the equations of motion for the shifting mass concept (also known as morphing) are developed. They are tested for their effects on attitude control by showing how shifting the mass changes the spacecraft's attitude behavior. Second, a method for optimal mass redistribution is shown using a combinatorial optimization theory under constraints. It closes with a simple example demonstrating an optimal reconfiguration. The procedure of optimal reconfiguration from one mass distribution to another to accomplish attitude control has been demonstrated for several simple examples. Mass shifting could work as an attitude controller for fine-tuning attitude behavior in small satellites. Various constraints can be applied for different situations, such as no mass shift between two tanks connected by a failed pipe or total amount of shifted mass per pipe being set for the time optimum solution. Euler angle changes influenced by the mass reconfiguration are accomplished while stability

  4. Transfer of training from a Full-Flight Simulator vs. a high level flight training device with a dynamic seat

    Science.gov (United States)

    2010-08-02

    This paper summarizes the most recent study conducted by the Federal Administration Administration/Volpe Center Flight Simulator Fidelity Requirements Program. For many smaller airlines, access to qualified simulators is limited due to the availabili...

  5. Using MathWorks' Simulink® and Real-Time Workshop® Code Generator to Produce Attitude Control Test and Flight Code

    OpenAIRE

    Salada, Mark; Dellinger, Wayne

    1998-01-01

    This paper describes the use of a commercial product, MathWorks' RealTime Workshop® (RTW), to generate actual flight code for NASA's Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics (TIMED) mission. The Johns Hopkins University Applied Physics Laboratory is handling the design and construction of this satellite for NASA. As TIMED is scheduled to launch in May of the year 2000, software development for both ground and flight systems are well on their way. However, based on experien...

  6. Polyculturalism and Sexist Attitudes: Believing Cultures are Dynamic Relates to Lower Sexism.

    Science.gov (United States)

    Rosenthal, Lisa; Levy, Sheri R; Militano, Maria

    2014-12-01

    In cultural contexts in which sexist beliefs are considered traditional, shifts toward gender equality represent an example of cultural change. Polyculturalism is defined as the belief that cultures change constantly through different racial and ethnic groups' interactions, influences, and exchanges with each other and, therefore, are dynamic and socially constructed rather than static. Thus, polyculturalism may involve openness to cultural change and, thereby, would be expected to be associated with lower sexist attitudes. Four studies (both cross-sectional and longitudinal) with undergraduate and community samples in the Northeastern United States tested whether endorsement of polyculturalism is inversely associated with sexism, above and beyond potentially confounding belief systems. Across studies, for both women and men, endorsement of polyculturalism was associated with lower sexist attitudes for two classes of sexism measures: (a) attitudes toward the rights and roles of women and (b) ambivalent sexist attitudes toward women. Associations remained significant while controlling for potentially confounding variables (colorblindness, conservatism, egalitarianism, gender and ethnic identity, gender and race essentialism, multiculturalism, right-wing authoritarianism, and social dominance orientation). Greater openness to criticizing one's culture mediated polyculturalism's association with attitudes toward the rights and roles of women but not with ambivalent sexist attitudes toward women. Studying polyculturalism may provide unique insights into sexism, and more work is needed to understand the mechanisms involved.

  7. Aircraft Attitude Distributed Fault-tolerant Control Based on Dynamic Actuator

    Directory of Open Access Journals (Sweden)

    Zhou Hong-Cheng

    2014-09-01

    Full Text Available For attitude control system, based on decentralized fault-tolerant control framework, actuators damage and stuck fault detection and identification unit are designed for the flight control system. And observer-based auxiliary system unit is also designed. The auxiliary system implies control surface damage faults and disturbances information. Firstly, we give the attitude control system under actuator stuck, lose of effectiveness, and control surface damages faults. Secondly, a multi-observer is designed for actuator fault detection and identification using a decision-making mechanism to determine current actuator failure modes. Then, an adaptive sliding mode observer is designed for implicit control surface damages and interference information. The reconfigurable controller can achieve fault tolerant using the information of adaptive sliding mode observer. Finally, the simulation results show the effectiveness of the proposed method.

  8. Species-specific flight styles of flies are reflected in the response dynamics of a homologue motion sensitive neuron

    Directory of Open Access Journals (Sweden)

    Bart eGeurten

    2012-03-01

    Full Text Available Hoverflies and blowflies have distinctly different flight styles. Yet, both species have been shown to structure their flight behaviour in a way that facilitates extraction of 3D information from the image flow on the retina (optic flow. Neuronal candidates to analyse the optic flow are the tangential cells in the third optical ganglion – the lobula complex. These neurons are directionally selective and integrate the optic flow over large parts of the visual field. Homologue tangential cells in hoverflies and blowflies have a similar morphology. Because blowflies and hoverflies have similar neuronal layout but distinctly different flight behaviours, they are an ideal substrate to pinpoint potential neuronal adaptations to the different flight styles.In this article we describe the relationship between locomotion behaviour and motion vision on three different levels:1.We compare the different flight styles based on the categorisation of flight behaviour into prototypical movements.2.We measure the species specific dynamics of the optic flow under naturalistic flight conditions. We found the translational optic flow of both species to be very different.3.We describe possible adaptations of a homologue motion sensitive neuron. We stimulate this cell in blowflies (Calliphora and hoverflies (Eristalis with naturalistic optic flow generated by both species during free flight. The characterized hoverfly tangential cell responds faster to transient changes in the optic flow than its blowfly homologue. It is discussed whether and how the different dynamical response properties aid optic flow analysis.

  9. Flight dynamics of some Lepidoptera species of sugar beet and possibilities their control (Transylvania-Romania

    Directory of Open Access Journals (Sweden)

    Muresanu Felicia

    2006-01-01

    Full Text Available In this paper, the authors present the obtained results regarding the flight dynamics of some Lepidoptera species in sugar beet crops in Transylvania (the central part of Romania. In order to limit the appearance of mentioned pests to the economic threshold, Trichogramma spp. were obtained in laboratory conditions at ARDS Turda and SBRDS Brasov. The experiments were conducted in production areas on 0,5 ha minimum for each variant. The variants included four Trichogramma species: T. dendrolimi, T. evanescens, T. maidis, T. buesi that were manually released three times: the first release, 10.000 individuals/ha, the second, 120.000 individuals/ha and the third, 150.000 individuals/ha. The first release was performed at the beginning of the Lepidoptera flight, the second at the maximum flight and the third 5 days after the second. The efficiency of T. maidis was between 75-90%, of T. evanescens, it was between 73-88%, of T. dendrolimi, it was between 85-92% and of T. buesi 79-82%. Among the Trichogramma species utilized, T. dendrolimi and T. evanescens were very efficient in the reduction of mentioned pests. Root production was significantly higher compared to the untreated variant, 4,0-4,7 t/ha more were recorded after the application of biological treatments with T. evanescens and T. dendrolimi.

  10. The Coupled Orbit-Attitude Dynamics and Control of Electric Sail in Displaced Solar Orbits

    Directory of Open Access Journals (Sweden)

    Mingying Huo

    2017-01-01

    Full Text Available Displaced solar orbits for spacecraft propelled by electric sails are investigated. Since the propulsive thrust is induced by the sail attitude, the orbital and attitude dynamics of electric-sail-based spacecraft are coupled and required to be investigated together. However, the coupled dynamics and control of electric sails have not been discussed in most published literatures. In this paper, the equilibrium point of the coupled dynamical system in displaced orbit is obtained, and its stability is analyzed through a linearization. The results of stability analysis show that only some of the orbits are marginally stable. For unstable displaced orbits, linear quadratic regulator is employed to control the coupled attitude-orbit system. Numerical simulations show that the proposed strategy can control the coupled system and a small torque can stabilize both the attitude and orbit. In order to generate the control force and torque, the voltage distribution problem is studied in an optimal framework. The numerical results show that the control force and torque of electric sail can be realized by adjusting the voltage distribution of charged tethers.

  11. Malaria prevention knowledge, attitudes, and practices (KAP) among international flying pilots and flight attendants of a US commercial airline.

    Science.gov (United States)

    Selent, Monica; de Rochars, Valery M Beau; Stanek, Danielle; Bensyl, Diana; Martin, Barbara; Cohen, Nicole J; Kozarsky, Phyllis; Blackmore, Carina; Bell, Teal R; Marano, Nina; Arguin, Paul M

    2012-12-01

    In 2010, malaria caused approximately 216 million infections in people and 655,000 deaths. In the United States, imported malaria cases occur every year, primarily in returning travelers and immigrants from endemic countries. In 2010, five Plasmodium falciparum malaria cases occurred among crew members of one US commercial airline company (Airline A). This investigation aimed to assess the malaria prevention knowledge, attitudes, and practices (KAP) of Airline A crew members to provide information for potential interventions. The web link to a self-administered on-line survey was distributed by internal company communications to Airline A pilots and flight attendants (FA) eligible for international travel. The survey collected demographic information as well as occupation, work history, and malaria prevention education. Of approximately 7,000 nonrandomly selected crew members, 220 FA and 217 pilots completed the survey (6%). Respondents correctly identified antimalarial medication (91% FA, 95% pilots) and insect repellents (96% FA, 96% pilots) as effective preventive measures. While in malaria-intense destinations, few FA and less than half of pilots always took antimalarial medication (4% FA, 40% pilots) yet many often spent greater than 30 minutes outdoors after sundown (71% FA, 66% pilots). Less than half in both groups always used insect repellents (46% FA, 47% pilots). Many respondents were unaware of how to get antimalarial medications (52% FA, 30% pilots) and were concerned about their side effects (61% FA, 31% pilots). Overall, FA and pilots demonstrated good knowledge of malaria prevention, but many performed risky activities while practicing only some recommended malaria preventive measures. Malaria prevention education should focus on advance notification if traveling to a malaria-endemic area, how to easily obtain antimalarial medications, and the importance of practicing all recommended preventive measures. © 2012 International Society of Travel

  12. NASA LaRC Workshop on Guidance, Navigation, Controls, and Dynamics for Atmospheric Flight, 1993

    Science.gov (United States)

    Buttrill, Carey S. (Editor)

    1993-01-01

    This publication is a collection of materials presented at a NASA workshop on guidance, navigation, controls, and dynamics (GNC&D) for atmospheric flight. The workshop was held at the NASA Langley Research Center on March 18-19, 1993. The workshop presentations describe the status of current research in the GNC&D area at Langley over a broad spectrum of research branches. The workshop was organized in eight sessions: overviews, general, controls, military aircraft, dynamics, guidance, systems, and a panel discussion. A highlight of the workshop was the panel discussion which addressed the following issue: 'Direction of guidance, navigation, and controls research to ensure U.S. competitiveness and leadership in aerospace technologies.'

  13. Flight dynamics facility operational orbit determination support for the ocean topography experiment

    Science.gov (United States)

    Bolvin, D. T.; Schanzle, A. F.; Samii, M. V.; Doll, C. E.

    1991-01-01

    The Ocean Topography Experiment (TOPEX/POSEIDON) mission is designed to determine the topography of the Earth's sea surface across a 3 yr period, beginning with launch in June 1992. The Goddard Space Flight Center Dynamics Facility has the capability to operationally receive and process Tracking and Data Relay Satellite System (TDRSS) tracking data. Because these data will be used to support orbit determination (OD) aspects of the TOPEX mission, the Dynamics Facility was designated to perform TOPEX operational OD. The scientific data require stringent OD accuracy in navigating the TOPEX spacecraft. The OD accuracy requirements fall into two categories: (1) on orbit free flight; and (2) maneuver. The maneuver OD accuracy requirements are of two types; premaneuver planning and postmaneuver evaluation. Analysis using the Orbit Determination Error Analysis System (ODEAS) covariance software has shown that, during the first postlaunch mission phase of the TOPEX mission, some postmaneuver evaluation OD accuracy requirements cannot be met. ODEAS results also show that the most difficult requirements to meet are those that determine the change in the components of velocity for postmaneuver evaluation.

  14. A Numerical Approach to Determine Attitude Dynamics of Floating Bodies with Irregular Configurations

    Directory of Open Access Journals (Sweden)

    Jiann-Lin Chen

    2014-07-01

    Full Text Available This study acquires the attitude dynamics of floating bodies with irregular configurations using an effective computational model, which has been validated theoretically and verified by experiments. By comparison a correlation formula was described to predict inclinations for the floating slender body imitating an excise torpedo. Thereafter a computational model was developed to account for bodies with attitudes in more general situations. For demonstration, a submersible was simulated to reveal that the inclinations vary abruptly around certain longitudinal locations of center of gravity. The property variations during water ingress assumption were presented. Similar to the virtue tank, an innovative concept of building the numerical data base for a specific floating body has been proposed, by which the position of its center of gravity can be obtained by interpolation from attitude data in tables as determined by the present computational model.

  15. Optical Feather and Foil for Shape and Dynamic Load Sensing of Critical Flight Surfaces, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Future flight vehicles may comprise complex flight surfaces requiring coordinated in-situ sensing and actuation. Inspired by the complexity of the flight surfaces on...

  16. Design Criteria for the Future of Flight Controls. Proceedings of the Flight Dynamics Laboratory Flying Qualities and Flight Control Symposium 2-5 March 1982.

    Science.gov (United States)

    1982-07-01

    launch platform . But as a transport, obviously, long duration flights must be accomplished without undue crew fatigue. Underlying all this is an...Modes a weapons platforme throah sore effective flight listed in Figure 1. control design. VII. Sugestd Frthr Research Rfrne There are certain...A KIat KiOW CC~~i at Pilot m1A~ MloU. ftm of a h m ad ftf trn* weD kqr~&~ m Wix a I -n ** Wuma of Am 1 Tbalam, ad axazw Dpi c Fwa PltwsAp ad A

  17. Nonlinear model and attitude dynamics of flexible spacecraft with large amplitude slosh

    Science.gov (United States)

    Deng, Mingle; Yue, Baozeng

    2017-04-01

    This paper is focused on the nonlinearly modelling and attitude dynamics of spacecraft coupled with large amplitude liquid sloshing dynamics and flexible appendage vibration. The large amplitude fuel slosh dynamics is included by using an improved moving pulsating ball model. The moving pulsating ball model is an equivalent mechanical model that is capable of imitating the whole liquid reorientation process. A modification is introduced in the capillary force computation in order to more precisely estimate the settling location of liquid in microgravity or zero-g environment. The flexible appendage is modelled as a three dimensional Bernoulli-Euler beam and the assumed modal method is employed to derive the nonlinear mechanical model for the overall coupled system of liquid filled spacecraft with appendage. The attitude maneuver is implemented by the momentum transfer technique, and a feedback controller is designed. The simulation results show that the liquid sloshing can always result in nutation behavior, but the effect of flexible deformation of appendage depends on the amplitude and direction of attitude maneuver performed by spacecraft. Moreover, it is found that the liquid sloshing and the vibration of flexible appendage are coupled with each other, and the coupling becomes more significant with more rapid motion of spacecraft. This study reveals that the appendage's flexibility has influence on the liquid's location and settling time in microgravity. The presented nonlinear system model can provide an important reference for the overall design of the modern spacecraft composed of rigid platform, liquid filled tank and flexible appendage.

  18. Methodology to Support Dynamic Function Allocation Policies Between Humans and Flight Deck Automation

    Science.gov (United States)

    Johnson, Eric N.

    2012-01-01

    Function allocation assigns work functions to all agents in a team, both human and automation. Efforts to guide function allocation systematically have been studied in many fields such as engineering, human factors, team and organization design, management science, cognitive systems engineering. Each field focuses on certain aspects of function allocation, but not all; thus, an independent discussion of each does not address all necessary aspects of function allocation. Four distinctive perspectives have emerged from this comprehensive review of literature on those fields: the technology-centered, human-centered, team-oriented, and work-oriented perspectives. Each perspective focuses on different aspects of function allocation: capabilities and characteristics of agents (automation or human), structure and strategy of a team, and work structure and environment. This report offers eight issues with function allocation that can be used to assess the extent to which each of issues exist on a given function allocation. A modeling framework using formal models and simulation was developed to model work as described by the environment, agents, their inherent dynamics, and relationships among them. Finally, to validate the framework and metrics, a case study modeled four different function allocations between a pilot and flight deck automation during the arrival and approach phases of flight.

  19. Flight dynamics of a pterosaur-inspired aircraft utilizing a variable-placement vertical tail

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Brian; Lind, Rick [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States); Chatterjee, Sankar, E-mail: ricklind@ufl.edu [Department of Geology and Paleontology Museum, Texas Tech University, Lubbock, TX 79409 (United States)

    2011-06-15

    Mission performance for small aircraft is often dependent on the turn radius. Various biologically inspired concepts have demonstrated that performance can be improved by morphing the wings in a manner similar to birds and bats; however, the morphing of the vertical tail has received less attention since neither birds nor bats have an appreciable vertical tail. This paper investigates a design that incorporates the morphing of the vertical tail based on the cranial crest of a pterosaur. The aerodynamics demonstrate a reduction in the turn radius of 14% when placing the tail over the nose in comparison to a traditional aft-placed vertical tail. The flight dynamics associated with this configuration has unique characteristics such as a Dutch-roll mode with excessive roll motion and a skid divergence that replaces the roll convergence.

  20. Flight dynamics of a pterosaur-inspired aircraft utilizing a variable-placement vertical tail

    International Nuclear Information System (INIS)

    Roberts, Brian; Lind, Rick; Chatterjee, Sankar

    2011-01-01

    Mission performance for small aircraft is often dependent on the turn radius. Various biologically inspired concepts have demonstrated that performance can be improved by morphing the wings in a manner similar to birds and bats; however, the morphing of the vertical tail has received less attention since neither birds nor bats have an appreciable vertical tail. This paper investigates a design that incorporates the morphing of the vertical tail based on the cranial crest of a pterosaur. The aerodynamics demonstrate a reduction in the turn radius of 14% when placing the tail over the nose in comparison to a traditional aft-placed vertical tail. The flight dynamics associated with this configuration has unique characteristics such as a Dutch-roll mode with excessive roll motion and a skid divergence that replaces the roll convergence.

  1. Dynamical Modeling of Collective Behavior from Pigeon Flight Data: Flock Cohesion and Dispersion

    Science.gov (United States)

    Xu, Xiao-Ke; Small, Michael

    2012-01-01

    Several models of flocking have been promoted based on simulations with qualitatively naturalistic behavior. In this paper we provide the first direct application of computational modeling methods to infer flocking behavior from experimental field data. We show that this approach is able to infer general rules for interaction, or lack of interaction, among members of a flock or, more generally, any community. Using experimental field measurements of homing pigeons in flight we demonstrate the existence of a basic distance dependent attraction/repulsion relationship and show that this rule is sufficient to explain collective behavior observed in nature. Positional data of individuals over time are used as input data to a computational algorithm capable of building complex nonlinear functions that can represent the system behavior. Topological nearest neighbor interactions are considered to characterize the components within this model. The efficacy of this method is demonstrated with simulated noisy data generated from the classical (two dimensional) Vicsek model. When applied to experimental data from homing pigeon flights we show that the more complex three dimensional models are capable of simulating trajectories, as well as exhibiting realistic collective dynamics. The simulations of the reconstructed models are used to extract properties of the collective behavior in pigeons, and how it is affected by changing the initial conditions of the system. Our results demonstrate that this approach may be applied to construct models capable of simulating trajectories and collective dynamics using experimental field measurements of herd movement. From these models, the behavior of the individual agents (animals) may be inferred. PMID:22479176

  2. Dynamical modeling of collective behavior from pigeon flight data: flock cohesion and dispersion.

    Directory of Open Access Journals (Sweden)

    Graciano Dieck Kattas

    Full Text Available Several models of flocking have been promoted based on simulations with qualitatively naturalistic behavior. In this paper we provide the first direct application of computational modeling methods to infer flocking behavior from experimental field data. We show that this approach is able to infer general rules for interaction, or lack of interaction, among members of a flock or, more generally, any community. Using experimental field measurements of homing pigeons in flight we demonstrate the existence of a basic distance dependent attraction/repulsion relationship and show that this rule is sufficient to explain collective behavior observed in nature. Positional data of individuals over time are used as input data to a computational algorithm capable of building complex nonlinear functions that can represent the system behavior. Topological nearest neighbor interactions are considered to characterize the components within this model. The efficacy of this method is demonstrated with simulated noisy data generated from the classical (two dimensional Vicsek model. When applied to experimental data from homing pigeon flights we show that the more complex three dimensional models are capable of simulating trajectories, as well as exhibiting realistic collective dynamics. The simulations of the reconstructed models are used to extract properties of the collective behavior in pigeons, and how it is affected by changing the initial conditions of the system. Our results demonstrate that this approach may be applied to construct models capable of simulating trajectories and collective dynamics using experimental field measurements of herd movement. From these models, the behavior of the individual agents (animals may be inferred.

  3. CFD based aerodynamic modeling to study flight dynamics of a flapping wing micro air vehicle

    Science.gov (United States)

    Rege, Alok Ashok

    The demand for small unmanned air vehicles, commonly termed micro air vehicles or MAV's, is rapidly increasing. Driven by applications ranging from civil search-and-rescue missions to military surveillance missions, there is a rising level of interest and investment in better vehicle designs, and miniaturized components are enabling many rapid advances. The need to better understand fundamental aspects of flight for small vehicles has spawned a surge in high quality research in the area of micro air vehicles. These aircraft have a set of constraints which are, in many ways, considerably different from that of traditional aircraft and are often best addressed by a multidisciplinary approach. Fast-response non-linear controls, nano-structures, integrated propulsion and lift mechanisms, highly flexible structures, and low Reynolds aerodynamics are just a few of the important considerations which may be combined in the execution of MAV research. The main objective of this thesis is to derive a consistent nonlinear dynamic model to study the flight dynamics of micro air vehicles with a reasonably accurate representation of aerodynamic forces and moments. The research is divided into two sections. In the first section, derivation of the nonlinear dynamics of flapping wing micro air vehicles is presented. The flapping wing micro air vehicle (MAV) used in this research is modeled as a system of three rigid bodies: a body and two wings. The design is based on an insect called Drosophila Melanogaster, commonly known as fruit-fly. The mass and inertial effects of the wing on the body are neglected for the present work. The nonlinear dynamics is simulated with the aerodynamic data published in the open literature. The flapping frequency is used as the control input. Simulations are run for different cases of wing positions and the chosen parameters are studied for boundedness. Results show a qualitative inconsistency in boundedness for some cases, and demand a better

  4. The Propulsive-Only Flight Control Problem

    Science.gov (United States)

    Blezad, Daniel J.

    1996-01-01

    Attitude control of aircraft using only the throttles is investigated. The long time constants of both the engines and of the aircraft dynamics, together with the coupling between longitudinal and lateral aircraft modes make piloted flight with failed control surfaces hazardous, especially when attempting to land. This research documents the results of in-flight operation using simulated failed flight controls and ground simulations of piloted propulsive-only control to touchdown. Augmentation control laws to assist the pilot are described using both optimal control and classical feedback methods. Piloted simulation using augmentation shows that simple and effective augmented control can be achieved in a wide variety of failed configurations.

  5. Total aircraft flight-control system - Balanced open- and closed-loop control with dynamic trim maps

    Science.gov (United States)

    Smith, G. A.; Meyer, G.

    1979-01-01

    The availability of the airborne digital computer has made possible a Total Aircraft Flight Control System (TAFCOS) that uses virtually the complete nonlinear propulsive and aerodynamic data for the aircraft to construct dynamic trim maps that represent an inversion of the aircraft model. The trim maps, in series with the aircraft, provide essentially a linear feed-forward path. Basically, open-loop trajectory control is employed with only a small perturbation feedback signal required to compensate for inaccuracy in the aircraft model and for external disturbances. Simulation results for application to an automatic carrier-landing system are presented. Flight-test results for a STOL aircraft operating automatically over a major portion of its flight regime are presented. The concept promises a more rapid and straightforward design from aerodynamic principles, particularly for highly nonlinear configurations, and requires substantially less digital computer capacity than conventional automatic flight-control system designs.

  6. Optimization of detectors positioning with respect to flying dynamics for future formation flight missions

    Science.gov (United States)

    Civitani, Marta; Djalal, Sophie; Chipaux, Remi

    2009-08-01

    In a X-ray telescope in formation flight configuration, the optics and the focal-plane detectors reside in two different spacecraft. The dynamics of the detector spacecraft (DSC) with respect to the mirror spacecraft (MSC, carrying the mirrors of the telescope) changes continuously the arrival positions of the photons on the detectors. In this paper we analyze this issue for the case of the SIMBOL-X hard X-ray mission, extensively studied by CNES and ASI until 2009 spring. Due to the existing gaps between pixels and between detector modules, the dynamics of the system may produce a relevant photometric effect. The aim of this work is to present the optimization study of the control-law algorithm with respect to the detector's geometry. As the photometric effect may vary depending upon position of the source image on the detector, the analysis-carried out using the simuLOS (INAF, CNES, CEA) simulation tool-is extended over the entire SIMBOL-X field of view.

  7. Dynamics of 3D Timoshenko gyroelastic beams with large attitude changes for the gyros

    Science.gov (United States)

    Hassanpour, Soroosh; Heppler, G. R.

    2016-01-01

    This work is concerned with the theoretical development of dynamic equations for undamped gyroelastic beams which are dynamic systems with continuous inertia, elasticity, and gyricity. Assuming unrestricted or large attitude changes for the axes of the gyros and utilizing generalized Hooke's law, Duleau torsion theory, and Timoshenko bending theory, the energy expressions and equations of motion for the gyroelastic beams in three-dimensional space are derived. The so-obtained comprehensive gyroelastic beam model is compared against earlier gyroelastic beam models developed using Euler-Bernoulli beam models and is used to study the dynamics of gyroelastic beams through numerical examples. It is shown that there are significant differences between the developed unrestricted Timoshenko gyroelastic beam model and the previously derived zero-order restricted Euler-Bernoulli gyroelastic beam models. These differences are more pronounced in the short beam and transverse gyricity cases.

  8. Fault Detection and Correction for the Solar Dynamics Observatory Attitude Control System

    Science.gov (United States)

    Starin, Scott R.; Vess, Melissa F.; Kenney, Thomas M.; Maldonado, Manuel D.; Morgenstern, Wendy M.

    2007-01-01

    The Solar Dynamics Observatory is an Explorer-class mission that will launch in early 2009. The spacecraft will operate in a geosynchronous orbit, sending data 24 hours a day to a devoted ground station in White Sands, New Mexico. It will carry a suite of instruments designed to observe the Sun in multiple wavelengths at unprecedented resolution. The Atmospheric Imaging Assembly includes four telescopes with focal plane CCDs that can image the full solar disk in four different visible wavelengths. The Extreme-ultraviolet Variability Experiment will collect time-correlated data on the activity of the Sun's corona. The Helioseismic and Magnetic Imager will enable study of pressure waves moving through the body of the Sun. The attitude control system on Solar Dynamics Observatory is responsible for four main phases of activity. The physical safety of the spacecraft after separation must be guaranteed. Fine attitude determination and control must be sufficient for instrument calibration maneuvers. The mission science mode requires 2-arcsecond control according to error signals provided by guide telescopes on the Atmospheric Imaging Assembly, one of the three instruments to be carried. Lastly, accurate execution of linear and angular momentum changes to the spacecraft must be provided for momentum management and orbit maintenance. In thsp aper, single-fault tolerant fault detection and correction of the Solar Dynamics Observatory attitude control system is described. The attitude control hardware suite for the mission is catalogued, with special attention to redundancy at the hardware level. Four reaction wheels are used where any three are satisfactory. Four pairs of redundant thrusters are employed for orbit change maneuvers and momentum management. Three two-axis gyroscopes provide full redundancy for rate sensing. A digital Sun sensor and two autonomous star trackers provide two-out-of-three redundancy for fine attitude determination. The use of software to maximize

  9. Population dynamics and flight phenology model of codling moth differ between commercial and abandoned apple orchard ecosystems

    Directory of Open Access Journals (Sweden)

    Neelendra K Joshi

    2016-09-01

    Full Text Available Apple orchard management practices may affect development and phenology of arthropod pests, such as the codling moth (CM, Cydia pomonella (L. (Lepidoptera: Tortricidae, which is a serious internal fruit-feeding pest of apples worldwide. Estimating population dynamics and accurately predicting the timing of CM development and phenology events (for instance, adult flight and egg-hatch allows growers to understand and control local populations of CM. Studies were conducted to compare the CM flight phenology in commercial and abandoned apple orchard ecosystems using a logistic function model based on degree-days accumulation. The flight models for these orchards were derived from the cumulative percent moth capture using two types of commercially available CM lure baited traps. Models from both types of orchards were also compared to another model known as PETE (prediction extension timing estimator that was developed in 1970s to predict life cycle events for many fruit pests including CM across different fruit growing regions of the United States. We found that the flight phenology of CM was significantly different in commercial and abandoned orchards. CM male flight patterns for first and second generations as predicted by the constrained and unconstrained PCM (Pennsylvania Codling Moth models in commercial and abandoned orchards were different than the flight patterns predicted by the currently used CM model (i.e.,1970’s model. In commercial orchards, during the first and second generations, the PCM unconstrained model predicted delays in moth emergence compared to current model. In addition, the flight patterns of females were different between commercial and abandoned orchards. Such differences in CM flight phenology between commercial and abandoned orchard ecosystems suggest potential impact of orchard environment and crop management practices on CM biology.

  10. Prediction of velocity and attitude of a yacht sailing upwind by computational fluid dynamics

    Directory of Open Access Journals (Sweden)

    Heebum Lee

    2016-01-01

    Full Text Available One of the most important factors in sailing yacht design is accurate velocity prediction. Velocity prediction programs (VPP's are widely used to predict velocity of sailing yachts. VPP's, which are primarily based on experimental data and experience of long years, however suffer limitations when applied in realistic conditions. Thus, in the present study, a high fidelity velocity prediction method using computational fluid dynamics (CFD was proposed. Using the developed method, velocity and attitude of a 30 feet sloop yacht, which was developed by Korea Research Institute of Ship and Ocean (KRISO and termed KORDY30, were predicted in upwind sailing condition.

  11. Modeling Flight: The Role of Dynamically Scaled Free-Flight Models in Support of NASA's Aerospace Programs

    Science.gov (United States)

    Chambers, Joseph

    2010-01-01

    The state of the art in aeronautical engineering has been continually accelerated by the development of advanced analysis and design tools. Used in the early design stages for aircraft and spacecraft, these methods have provided a fundamental understanding of physical phenomena and enabled designers to predict and analyze critical characteristics of new vehicles, including the capability to control or modify unsatisfactory behavior. For example, the relatively recent emergence and routine use of extremely powerful digital computer hardware and software has had a major impact on design capabilities and procedures. Sophisticated new airflow measurement and visualization systems permit the analyst to conduct micro- and macro-studies of properties within flow fields on and off the surfaces of models in advanced wind tunnels. Trade studies of the most efficient geometrical shapes for aircraft can be conducted with blazing speed within a broad scope of integrated technical disciplines, and the use of sophisticated piloted simulators in the vehicle development process permits the most important segment of operations the human pilot to make early assessments of the acceptability of the vehicle for its intended mission. Knowledgeable applications of these tools of the trade dramatically reduce risk and redesign, and increase the marketability and safety of new aerospace vehicles. Arguably, one of the more viable and valuable design tools since the advent of flight has been testing of subscale models. As used herein, the term "model" refers to a physical article used in experimental analyses of a larger full-scale vehicle. The reader is probably aware that many other forms of mathematical and computer-based models are also used in aerospace design; however, such topics are beyond the intended scope of this document. Model aircraft have always been a source of fascination, inspiration, and recreation for humans since the earliest days of flight. Within the scientific

  12. Aperiodic dynamics in a deterministic adaptive network model of attitude formation in social groups

    Science.gov (United States)

    Ward, Jonathan A.; Grindrod, Peter

    2014-07-01

    Adaptive network models, in which node states and network topology coevolve, arise naturally in models of social dynamics that incorporate homophily and social influence. Homophily relates the similarity between pairs of nodes' states to their network coupling strength, whilst social influence causes coupled nodes' states to convergence. In this paper we propose a deterministic adaptive network model of attitude formation in social groups that includes these effects, and in which the attitudinal dynamics are represented by an activato-inhibitor process. We illustrate that consensus, corresponding to all nodes adopting the same attitudinal state and being fully connected, may destabilise via Turing instability, giving rise to aperiodic dynamics with sensitive dependence on initial conditions. These aperiodic dynamics correspond to the formation and dissolution of sub-groups that adopt contrasting attitudes. We discuss our findings in the context of cultural polarisation phenomena. Social influence. This reflects the fact that people tend to modify their behaviour and attitudes in response to the opinions of others [22-26]. We model social influence via diffusion: agents adjust their state according to a weighted sum (dictated by the evolving network) of the differences between their state and the states of their neighbours. Homophily. This relates the similarity of individuals' states to their frequency and strength of interaction [27]. Thus in our model, homophily drives the evolution of the weighted ‘social' network. A precise formulation of our model is given in Section 2. Social influence and homophily underpin models of social dynamics [21], which cover a wide range of sociological phenomena, including the diffusion of innovations [28-32], complex contagions [33-36], collective action [37-39], opinion dynamics [19,20,40,10,11,13,15,41,16], the emergence of social norms [42-44], group stability [45], social differentiation [46] and, of particular relevance

  13. The role of situation assessment and flight experience in pilots' decisions to continue visual flight rules flight into adverse weather.

    Science.gov (United States)

    Wiegmann, Douglas A; Goh, Juliana; O'Hare, David

    2002-01-01

    Visual flight rules (VFR) flight into instrument meteorological conditions (IMC) is a major safety hazard in general aviation. In this study we examined pilots' decisions to continue or divert from a VFR flight into IMC during a dynamic simulation of a cross-country flight. Pilots encountered IMC either early or later into the flight, and the amount of time and distance pilots flew into the adverse weather prior to diverting was recorded. Results revealed that pilots who encountered the deteriorating weather earlier in the flight flew longer into the weather prior to diverting and had more optimistic estimates of weather conditions than did pilots who encountered the deteriorating weather later in the flight. Both the time and distance traveled into the weather prior to diverting were negatively correlated with pilots' previous flight experience. These findings suggest that VFR flight into IMC may be attributable, at least in part, to poor situation assessment and experience rather than to motivational judgment that induces risk-taking behavior as more time and effort are invested in a flight. Actual or potential applications of this research include the design of interventions that focus on improving weather evaluation skills in addition to addressing risk-taking attitudes.

  14. Simbol-X Formation Flight and Image Reconstruction

    Science.gov (United States)

    Civitani, M.; Djalal, S.; Le Duigou, J. M.; La Marle, O.; Chipaux, R.

    2009-05-01

    Simbol-X is the first operational mission relying on two satellites flying in formation. The dynamics of the telescope, due to the formation flight concept, raises a variety of problematic, like image reconstruction, that can be better evaluated via a simulation tools. We present here the first results obtained with Simulos, simulation tool aimed to study the relative spacecrafts navigation and the weight of the different parameters in image reconstruction and telescope performance evaluation. The simulation relies on attitude and formation flight sensors models, formation flight dynamics and control, mirror model and focal plane model, while the image reconstruction is based on the Line of Sight (LOS) concept.

  15. Flight Dynamics Operations Management of the Large and Heterogeneous Eutelsat Fleet of Commercial Satellites

    Science.gov (United States)

    Bellido, E.

    The EUTELSAT FDU (Flight Dynamics Unit) manages the resources to perform the typical activities of the large satellite operators and faces the usual difficulties raising from a vast and heterogeneous fleet. At present 20 satellites from 9 different platforms/sub-platforms are controlled from our Satellite Control Centre. The FDU was created in 2002 with the aim to respond to the operational needs of a growing fleet in terms of number of satellites and activities. It is at present composed of 6 engineering staff with the objective to provide operations service covering the whole lifecycle of the satellites from the procurement phase till the decommissioning. The most demanding activity is the daily operations, which must ensure maximum safety and continuity of service with the highest efficiency. Solutions have been applied from different areas: management, structure, operations organisation, processes, facilities, quality standards, etc. In addition to this, EUTELSAT is a growing communications operator and the FDU needs to contribute to the global objectives of the company. This paper covers our approach.

  16. Dynamics and cultural specifics of information needs under conditions of long-term space flight

    Science.gov (United States)

    Feichtinger, Elena; Shved, Dmitry; Gushin, Vadim

    Life in conditions of space flight or chamber study with prolonged isolation is associated with lack of familiar stimuli (sensory deprivation), monotony, significant limitation of communication, and deficit of information and media content (Myasnikov V.I., Stepanova S.I. et al., 2000). Fulfillment of a simulation experiment or flight schedule implies necessity of performance of sophisticated tasks and decision making with limited means of external support. On the other hand, the “stream” of information from the Mission Control (MC) and PI’s (reminders about different procedures to be performed, requests of reports, etc.) is often inadequate to communication needs of crewmembers. According to the theory of “information stress” (Khananashvili M.M., 1984), a distress condition could be formed if: a) it’s necessary to process large amounts of information and make decisions under time pressure; b) there is a prolonged deficit of necessary (e.g. for decision making) information. Thus, we suppose that one of the important goals of psychological support of space or space simulation crews should be forming of favorable conditions of information environment. For that purpose, means of crew-MC information exchange (quantitative characteristics and, if possible, content of radiograms, text and video messages, etc.) should be studied, as well as peculiarities of the crewmembers’ needs in different information and media content, and their reactions to incoming information. In the space simulation experiment with 520-day isolation, communication of international crew with external parties had been studied. Dynamics of quantitative and content characteristics of the crew’s messages was related to the experiment’s stage, presence of “key” events in the schedule (periods of high autonomy, simulated “planetary landing”, etc.), as well as to events not related to the experiment (holidays, news, etc.). It was shown that characteristics of information exchange

  17. Strategies for the stabilization of longitudinal forward flapping flight revealed using a dynamically-scaled robotic fly

    International Nuclear Information System (INIS)

    Elzinga, Michael J; Van Breugel, Floris; Dickinson, Michael H

    2014-01-01

    The ability to regulate forward speed is an essential requirement for flying animals. Here, we use a dynamically-scaled robot to study how flapping insects adjust their wing kinematics to regulate and stabilize forward flight. The results suggest that the steady-state lift and thrust requirements at different speeds may be accomplished with quite subtle changes in hovering kinematics, and that these adjustments act primarily by altering the pitch moment. This finding is consistent with prior hypotheses regarding the relationship between body pitch and flight speed in fruit flies. Adjusting the mean stroke position of the wings is a likely mechanism for trimming the pitch moment at all speeds, whereas changes in the mean angle of attack may be required at higher speeds. To ensure stability, the flapping system requires additional pitch damping that increases in magnitude with flight speed. A compensatory reflex driven by fast feedback of pitch rate from the halteres could provide such damping, and would automatically exhibit gain scheduling with flight speed if pitch torque was regulated via changes in stroke deviation. Such a control scheme would provide an elegant solution for stabilization across a wide range of forward flight speeds. (paper)

  18. Nonlinear Dynamics in a Cournot Duopoly with Different Attitudes towards Strategic Uncertainty

    Directory of Open Access Journals (Sweden)

    Luciano Fanti

    2013-01-01

    Full Text Available This paper analyses the dynamics of a duopoly with quantity-setting firms and different attitudes towards strategic uncertainty. By following the recent literature on decision making under uncertainty, where the Choquet expected utility theory is adopted to allow firms to plan their strategies, we investigate the effects of the interaction between pessimistic and optimistic firms on economic dynamics described by a two-dimensional map. In particular, the study of the local and global behaviour of the map is performed under three assumptions: (1 both firms have complete information on the market demand and adjust production over time depending on past behaviours (static expectations—“best reply” dynamics; (2 both firms have incomplete information and production is adjusted over time by following a mechanism based on marginal profits; and (3 one firm has incomplete information on the market demand and production decisions are based on the behaviour of marginal profits, and the rival has complete information on the market demand and static expectations. In cases 2 and 3 it is shown that complex dynamics and coexistence of attractors may arise. The analysis is carried forward through numerical simulations and the critical lines technique.

  19. RHAGOLETIS COMPLETA (DIPTERA; TEPHRITIDAE DISTRIBUTION, FLIGHT DYNAMICS AND INFLUENCE ON WALNUT KERNEL QUALITY IN THE CONTINENTAL CROATIA

    Directory of Open Access Journals (Sweden)

    Božena Barić

    2015-06-01

    Full Text Available Walnut husk fly (WHF, Rhagoletis completa Cresson 1929 is an invasive species spreading quickly and damaging walnuts in Croatia and neighbouring countries. We researched distribution of this pest in the continental part of Croatia, flight dynamics in Međimurje County and its influence on quality of walnut kernels. CSALOMON®PALz traps were used for monitoring the spread and flight dynamics of R. completa. Weight and the protein content of kernels and the presence of mycotoxin contamination were measured. Walnut husk fly was found in six counties (Istria County: pest reconfirmation, Zagreb County, The City of Zagreb, Varaždin County, Međimurje County and Koprivnica-Križevci County. The presence of the fly was not confirmed on one site in Koprivnica-Križevci County (locality Ferdinandovac and in the eastern part of Croatia (Vukovar-Srijem County: Vinkovci locality. The flight dynamics showed rapid increase in number of adults only a year after the introduction into new area. The weight of infested kernels was 5.81% lower compared to not infested. Protein content was 14.04% in infested kernels and 17.31% in not infested kernels. There was no difference in mycotoxins levels. Additional researches on mycotoxin levels in stored nuts, ovipositional preferences of walnut husk fly and protection measures against this pest are suggested.

  20. Flight control of fruit flies: dynamic response to optic flow and headwind.

    Science.gov (United States)

    Lawson, Kiaran K K; Srinivasan, Mandyam V

    2017-06-01

    Insects are magnificent fliers that are capable of performing many complex tasks such as speed regulation, smooth landings and collision avoidance, even though their computational abilities are limited by their small brain. To investigate how flying insects respond to changes in wind speed and surrounding optic flow, the open-loop sensorimotor response of female Queensland fruit flies ( Bactrocera tryoni ) was examined. A total of 136 flies were exposed to stimuli comprising sinusoidally varying optic flow and air flow (simulating forward movement) under tethered conditions in a virtual reality arena. Two responses were measured: the thrust and the abdomen pitch. The dynamics of the responses to optic flow and air flow were measured at various frequencies, and modelled as a multicompartment linear system, which accurately captured the behavioural responses of the fruit flies. The results indicate that these two behavioural responses are concurrently sensitive to changes of optic flow as well as wind. The abdomen pitch showed a streamlining response, where the abdomen was raised higher as the magnitude of either stimulus was increased. The thrust, in contrast, exhibited a counter-phase response where maximum thrust occurred when the optic flow or wind flow was at a minimum, indicating that the flies were attempting to maintain an ideal flight speed. When the changes in the wind and optic flow were in phase (i.e. did not contradict each other), the net responses (thrust and abdomen pitch) were well approximated by an equally weighted sum of the responses to the individual stimuli. However, when the optic flow and wind stimuli were presented in counterphase, the flies seemed to respond to only one stimulus or the other, demonstrating a form of 'selective attention'. © 2017. Published by The Company of Biologists Ltd.

  1. Integrated 6-DOF Orbit-Attitude Dynamical Modeling and Control Using Geometric Mechanics

    Directory of Open Access Journals (Sweden)

    Ling Jiang

    2017-01-01

    Full Text Available The integrated 6-DOF orbit-attitude dynamical modeling and control have shown great importance in various missions, for example, formation flying and proximity operations. The integrated approach yields better performances than the separate one in terms of accuracy, efficiency, and agility. One challenge in the integrated approach is to find a unified representation for the 6-DOF motion with configuration space SE(3. Recently, exponential coordinates of SE(3 have been used in dynamics and control of the 6-DOF motion, however, only on the kinematical level. In this paper, we will improve the current method by adopting exponential coordinates on the dynamical level, by giving the relation between the second-order derivative of exponential coordinates and spacecraft’s accelerations. In this way, the 6-DOF motion in terms of exponential coordinates can be written as a second-order system with a quite compact form, to which a broader range of control theories, such as higher-order sliding modes, can be applied. For a demonstration purpose, a simple asymptotic tracking control law with almost global convergence is designed. Finally, the integrated modeling and control are applied to the body-fixed hovering over an asteroid and verified by a simulation, in which absolute motions of the spacecraft and asteroid are simulated separately.

  2. Evolution of the 'Trick' Dynamic Software Executive and Model Libraries for Reusable Flight Software, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to a need for cost-effective small satellite missions, Odyssey Space Research is proposing the development of a common flight software executive and a...

  3. Bifurcation Tools for Flight Dynamics Analysis and Control System Design, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of the project is the development of a computational package for bifurcation analysis and advanced flight control of aircraft. The development of...

  4. Coastal dynamics vs beach users attitudes and perceptions to enhance environmental conservation and management effectiveness.

    Science.gov (United States)

    Aretano, Roberta; Parlagreco, Luca; Semeraro, Teodoro; Zurlini, Giovanni; Petrosillo, Irene

    2017-10-15

    This work carries out a landscape analysis for the last 60years to compare the degree of preservation of two areas on the same Italian coastline characterized by different environmental protection levels: a National designated protected areas and a highly tourist coastal destination. The conversion of natural land-covers into human land uses were detected for protected and unprotected coastal stretches highlighting that the only establishment of a protected area is not enough to stem undesirable land-use outcomes. A survey analysis was also conducted to assess attitudes of beach users and to evaluate their perception of natural habitats, beach and coastal water quality, and coastal dynamic over time. The results of 2071 questionnaires showed that there is similarity between subjective and objective data. However, several beach users perceived a bad quality of coastal water in the legally unprotected coastal area. The implications from a planning and management perspective are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Enhancing the Learning Achievements and Attitudes of Taiwan Vocational School Students in Accounting with the Dynamic Assessment System

    Science.gov (United States)

    Shih, Ju-Ling; Ku, David Tawei; Hung, Su-Huan

    2013-01-01

    We investigate how the computerized dynamic assessment system improves the learning achievements of vocational high school students studying accounting. Our experiment was conducted under the one-group pretest-posttest design of 34 junior students. The questionnaire results were analyzed to determine student-learning attitudes and reactions toward…

  6. Developmental Dynamics of Intergroup Contact and Intergroup Attitudes: Long-Term Effects in Adolescence and Early Adulthood

    NARCIS (Netherlands)

    Wölfer, R.; van Zalk, M.H.W.; Schmid, K.; Hewstone, M.

    2016-01-01

    Intergroup contact represents a powerful way to improve intergroup attitudes and to overcome prejudice and discrimination. However, long-term effects of intergroup contact that consider social network dynamics have rarely been studied at a young age. Study 1 validated an optimized social network

  7. Comparison of linear intrascan and interscan dynamic ranges of Orbitrap and ion-mobility time-of-flight mass spectrometers.

    Science.gov (United States)

    Kaufmann, Anton; Walker, Stephan

    2017-11-30

    The linear intrascan and interscan dynamic ranges of mass spectrometers are important in metabolome and residue analysis. A large linear dynamic range is mandatory if both low- and high-abundance ions have to be detected and quantitated in heavy matrix samples. These performance criteria, as provided by modern high-resolution mass spectrometry (HRMS), were systematically investigated. The comparison included two generations of Orbitraps, and an ion mobility quadrupole time-of-flight (QTOF) system In addition, different scan modes, as provided by the utilized instruments, were investigated. Calibration curves of different compounds covering a concentration range of five orders of magnitude were measured to evaluate the linear interscan dynamic range. The linear intrascan dynamic range and the resulting mass accuracy were evaluated by repeating these measurements in the presence of a very intense background. Modern HRMS instruments can show linear dynamic ranges of five orders of magnitude. Often, however, the linear dynamic range is limited by the detection capability (sensitivity and selectivity) and by the electrospray ionization. Orbitraps, as opposed to TOF instruments, show a reduced intrascan dynamic range. This is due to the limited C-trap and Orbitrap capacity. The tested TOF instrument shows poorer mass accuracies than the Orbitraps. In contrast, hyphenation with an ion-mobility device seems not to affect the linear dynamic range. The linear dynamic range of modern HRMS instrumentation has been significantly improved. This also refers to the virtual absence of systematic mass shifts at high ion abundances. The intrascan dynamic range of the current Orbitrap technology may still be a limitation when analyzing complex matrix extracts. On the other hand, the linear dynamic range is not only limited by the detector technology, but can also be shortened by peripheral devices, where the ionization and transfer of ions take place. Copyright © 2017 John Wiley

  8. A manned maneuvering unit proximity operations planning and flight guidance display and control system

    Science.gov (United States)

    Gershzohn, Gary R.; Sirko, Robert J.; Zimmerman, K.; Jones, A. D.

    1990-01-01

    This task concerns the design, development, testing, and evaluation of a new proximity operations planning and flight guidance display and control system for manned space operations. A forecast, derivative manned maneuvering unit (MMU) was identified as a candidate for the application of a color, highway-in-the-sky display format for the presentation of flight guidance information. A silicon graphics 4D/20-based simulation is being developed to design and test display formats and operations concepts. The simulation includes the following: (1) real-time color graphics generation to provide realistic, dynamic flight guidance displays and control characteristics; (2) real-time graphics generation of spacecraft trajectories; (3) MMU flight dynamics and control characteristics; (4) control algorithms for rotational and translational hand controllers; (5) orbital mechanics effects for rendezvous and chase spacecraft; (6) inclusion of appropriate navigation aids; and (7) measurement of subject performance. The flight planning system under development provides for: (1) selection of appropriate operational modes, including minimum cost, optimum cost, minimum time, and specified ETA; (2) automatic calculation of rendezvous trajectories, en route times, and fuel requirements; (3) and provisions for manual override. Man/machine function allocations in planning and en route flight segments are being evaluated. Planning and en route data are presented on one screen composed of two windows: (1) a map display presenting a view perpendicular to the orbital plane, depicting flight planning trajectory and time data attitude display presenting attitude and course data for use en route; and (2) an attitude display presenting local vertical-local horizontal attitude data superimposed on a highway-in-the-sky or flight channel representation of the flight planned course. Both display formats are presented while the MMU is en route. In addition to these displays, several original display

  9. Dynamics of animal movement in an ecological context: dragonfly wing damage reduces flight performance and predation success.

    Science.gov (United States)

    Combes, S A; Crall, J D; Mukherjee, S

    2010-06-23

    Much of our understanding of the control and dynamics of animal movement derives from controlled laboratory experiments. While many aspects of animal movement can be probed only in these settings, a more complete understanding of animal locomotion may be gained by linking experiments on relatively simple motions in the laboratory to studies of more complex behaviours in natural settings. To demonstrate the utility of this approach, we examined the effects of wing damage on dragonfly flight performance in both a laboratory drop-escape response and the more natural context of aerial predation. The laboratory experiment shows that hindwing area loss reduces vertical acceleration and average flight velocity, and the predation experiment demonstrates that this type of wing damage results in a significant decline in capture success. Taken together, these results suggest that wing damage may take a serious toll on wild dragonflies, potentially reducing both reproductive success and survival.

  10. Ares I Flight Control System Design

    Science.gov (United States)

    Jang, Jiann-Woei; Alaniz, Abran; Hall, Robert; Bedrossian, Nazareth; Hall, Charles; Ryan, Stephen; Jackson, Mark

    2010-01-01

    The Ares I launch vehicle represents a challenging flex-body structural environment for flight control system design. This paper presents a design methodology for employing numerical optimization to develop the Ares I flight control system. The design objectives include attitude tracking accuracy and robust stability with respect to rigid body dynamics, propellant slosh, and flex. Under the assumption that the Ares I time-varying dynamics and control system can be frozen over a short period of time, the flight controllers are designed to stabilize all selected frozen-time launch control systems in the presence of parametric uncertainty. Flex filters in the flight control system are designed to minimize the flex components in the error signals before they are sent to the attitude controller. To ensure adequate response to guidance command, step response specifications are introduced as constraints in the optimization problem. Imposing these constraints minimizes performance degradation caused by the addition of the flex filters. The first stage bending filter design achieves stability by adding lag to the first structural frequency to phase stabilize the first flex mode while gain stabilizing the higher modes. The upper stage bending filter design gain stabilizes all the flex bending modes. The flight control system designs provided here have been demonstrated to provide stable first and second stage control systems in both Draper Ares Stability Analysis Tool (ASAT) and the MSFC 6DOF nonlinear time domain simulation.

  11. The Use of Dynamic Visual Acuity as a Functional Test of Gaze Stabilization Following Space Flight

    Science.gov (United States)

    Peters, B. T.; Mulavara, A. P.; Brady, R.; Miller, C. A.; Richards, J. T.; Warren, L. E.; Cohen, H. S.; Bloomberg, J. J.

    2006-01-01

    After prolonged exposure to a given gravitational environment the transition to another is accompanied by adaptations in the sensorimotor subsystems, including the vestibular system. Variation in the adaptation time course of these subsystems, and the functional redundancies that exist between them make it difficult to accurately assess the functional capacity and physical limitations of astro/cosmonauts using tests on individual subsystems. While isolated tests of subsystem performance may be the only means to address where interventions are required, direct measures of performance may be more suitable for assessing the operational consequences of incomplete adaptation to changes in the gravitational environment. A test of dynamic visual acuity (DVA) is currently being used in the JSC Neurosciences Laboratory as part of a series of measures to assess the efficacy of a countermeasure to mitigate postflight locomotor dysfunction. In the current protocol, subjects visual acuity is determined using Landolt ring optotypes presented sequentially on a computer display. Visual acuity assessments are made both while standing and while walking at 1.8 m/s on a motorized treadmill. The use of a psychophysical threshold detection algorithm reduces the required number of optotype presentations and the results can be presented immediately after the test. The difference between the walking and standing acuity measures provides a metric of the change in the subject s ability to maintain gaze fixation on the visual target while walking. This functional consequence is observable regardless of the underlying subsystem most responsible for the change. Data from 15 cosmo/astronauts have been collected following long-duration (approx. 6 months) stays in space using a visual target viewing distance of 4.0 meters. An investigation of the group mean shows a change in DVA soon after the flight that asymptotes back to baseline approximately one week following their return to earth. The

  12. Attitude Dynamics and Tracking Control of Spacecraft in the Presence of Gravity Oblateness Perturbations

    Directory of Open Access Journals (Sweden)

    Achim IONITA

    2016-03-01

    Full Text Available The orbital docking represents a problem of great importance in aerospace engineering. The paper aims to perform an analysis of docking maneuvers between a chaser vehicle and a target vehicle in permanent LEO (low earth orbit. The work begins with a study of the attitude dynamics modeling intended to define the strategy that facilitates the chaser movement toward a docking part of the target. An LQR (linear quadratic regulator approach presents an optimal control design that provides linearized closed-loop error dynamics for tracking a desired quaternion. The control law formulation is combined with the control architecture based on SDRE (State Dependent Riccati equation technique for rotational maneuvers, including the Earth oblateness perturbation. The chaser body-fixed frame must coincide with the target body-fixed frame at the docking moment. Then the implementation of the control architecture based on LQR technique using the computational tool MATLAB is carried out. In simulation of the docking strategy V-R bar operations are analyzed and the minimum accelerations needs the control of chaser vehicle. The simulation analysis of those maneuvers considered for a chaser vehicle and a target vehicle in LEO orbit is validated in a case study.

  13. The dynamics of blood biochemical parameters in cosmonauts during long-term space flights

    Science.gov (United States)

    Markin, Andrei; Strogonova, Lubov; Balashov, Oleg; Polyakov, Valery; Tigner, Timoty

    Most of the previously obtained data on cosmonauts' metabolic state concerned certain stages of the postflight period. In this connection, all conclusions, as to metabolism peculiarities during the space flight, were to a large extent probabilistic. The purpose of this work was study of metabolism characteristics in cosmonauts directly during long-term space flights. In the capillary blood samples taken from a finger, by "Reflotron IV" biochemical analyzer, "Boehringer Mannheim" GmbH, Germany, adapted to weightlessness environments, the activity of GOT, GPT, CK, gamma-GT, total and pancreatic amylase, as well as concentration of hemoglobin, glucose, total bilirubin, uric acid, urea, creatinine, total, HDL- and LDL cholesterol, triglycerides had been determined. HDL/LDL-cholesterol ratio also was computed. The crewmembers of 6 main missions to the "Mir" orbital station, a total of 17 cosmonauts, were examined. Biochemical tests were carryed out 30-60 days before lounch, and in the flights different stages between the 25-th and the 423-rd days of flights. In cosmonauts during space flight had been found tendency to increase, in compare with basal level, GOT, GPT, total amylase activity, glucose and total cholesterol concentration, and tendency to decrease of CK activity, hemoglobin, HDL-cholesterol concentration, and HDL/LDL — cholesterol ratio. Some definite trends in variations of other determined biochemical parameters had not been found. The same trends of mentioned biochemical parameters alterations observed in majority of tested cosmonauts, allows to suppose existence of connection between noted metabolic alterations with influence of space flight conditions upon cosmonaut's body. Variations of other studied blood biochemical parameters depends on, probably, pure individual causes.

  14. Dynamics of human flight on skis: improvements in safety and fairness in ski jumping.

    Science.gov (United States)

    Müller, W; Platzer, D; Schmölzer, B

    1996-08-01

    This study of ski jumping includes three areas of research: Wind tunnel measurements with world class athletes in various flight positions, field measurements during the World Championships in Ski Flying 1994 in Planica (Slovenia) and a highly reliable mapping of ski jumping to a computable simulation model. The results explain the effects of equipment, flight style changes, the reason for the enhanced tumbling risk and high gust sensitivity observed. Consequences can be drawn for changes to the FIS regulations, the design of jumping hills and training methods. The internationally induced anorexia of the athletes could be prohibited by a new ski length regulation. Women jumpers could become a real competitive threat.

  15. The Dynamic Method for Time-of-Flight Measurement of Thermal Neutron Spectra from Pulsed Sources

    International Nuclear Information System (INIS)

    Pepelyshev, Yu.N.; Tulaev, A.B.; Bobrakov, V.F.

    1994-01-01

    The time-of-flight method for a measurement of thermal neutron spectra in the pulsed neutron sources with high efficiency of neutron registration, more than 10 5 times higher in comparison with traditional one, is described. The main problems connected with the electric current technique for time-of-flight spectra measurement are examined. The methodical errors, problems of a special neutron detector design and other questions are discussed. Some experimental results, spectra from surfaces of the water and solid methane moderators, obtained in the pulsed reactor IBR-2 (Dubna, Russia) are presented. 4 refs., 5 figs

  16. The dynamic method for time-of-flight measurement of thermal neutron spectra from pulsed sources

    International Nuclear Information System (INIS)

    Pepyolyshev, Yu.N.; Chuklyaev, S.V.; Tulaev, A.B.; Bobrakov, V.F.

    1995-01-01

    A time-of-flight method for measurement of thermal neutron spectra in pulsed neutron sources with an efficiency more than 10 5 times higher than the standard method is described. The main problems associated with the electric current technique for time-of-flight spectra measurement are examined. The methodical errors, problems of special neutron detector design and other questions are discussed. Some experimental results for spectra from the surfaces of water and solid methane moderators obtained at the IBR-2 pulsed reactor (Dubna, Russia) are presented. (orig.)

  17. TOPLAR: Time of Flight with Larmor Precessions - or - How to extend the dynamic range of NSE spectrometers

    International Nuclear Information System (INIS)

    Van Well, A.A.; Bleuel, M.; Pappas, C.

    2011-01-01

    Neutron Spin Echo (NSE) spectrometers typically cover a dynamic range of three orders of magnitude at a given wavelength. At long Fourier times the limits are given by the homogeneity of precession fields. At short Fourier times, the quasi-elastic approximation and the NSE formalism mark a methodological limit. We propose to overcome this limitation and by combining Time Of Flight with Larmor precession to extend the capabilities of Neutron Spin Echo spectrometers towards short Fourier times. TOFLAR should be easily implemented on NSE spectrometers equipped with a chopper system such as IN15 or the planned WASP. (authors)

  18. Chaos as the hub of systems dynamics. The part I-The attitude control of spacecraft by involving in the heteroclinic chaos

    Science.gov (United States)

    Doroshin, Anton V.

    2018-06-01

    In this work the chaos in dynamical systems is considered as a positive aspect of dynamical behavior which can be applied to change systems dynamical parameters and, moreover, to change systems qualitative properties. From this point of view, the chaos can be characterized as a hub for the system dynamical regimes, because it allows to interconnect separated zones of the phase space of the system, and to fulfill the jump into the desirable phase space zone. The concretized aim of this part of the research is to focus on developing the attitude control method for magnetized gyrostat-satellites, which uses the passage through the intentionally generated heteroclinic chaos. The attitude dynamics of the satellite/spacecraft in this case represents the series of transitions from the initial dynamical regime into the chaotic heteroclinic regime with the subsequent exit to the final target dynamical regime with desirable parameters of the attitude dynamics.

  19. Application of the concept of dynamic trim control and nonlinear system inverses to automatic control of a vertical attitude takeoff and landing aircraft

    Science.gov (United States)

    Smith, G. A.; Meyer, G.

    1981-01-01

    A full envelope automatic flight control system based on nonlinear inverse systems concepts has been applied to a vertical attitude takeoff and landing (VATOL) fighter aircraft. A new method for using an airborne digital aircraft model to perform the inversion of a nonlinear aircraft model is presented together with the results of a simulation study of the nonlinear inverse system concept for the vertical-attitude hover mode. The system response to maneuver commands in the vertical attitude was found to be excellent; and recovery from large initial offsets and large disturbances was found to be very satisfactory.

  20. A dynamic human water and electrolyte balance model for verification and optimization of life support systems in space flight applications

    Science.gov (United States)

    Hager, P.; Czupalla, M.; Walter, U.

    2010-11-01

    In this paper we report on the development of a dynamic MATLAB SIMULINK® model for the water and electrolyte balance inside the human body. This model is part of an environmentally sensitive dynamic human model for the optimization and verification of environmental control and life support systems (ECLSS) in space flight applications. An ECLSS provides all vital supplies for supporting human life on board a spacecraft. As human space flight today focuses on medium- to long-term missions, the strategy in ECLSS is shifting to closed loop systems. For these systems the dynamic stability and function over long duration are essential. However, the only evaluation and rating methods for ECLSS up to now are either expensive trial and error breadboarding strategies or static and semi-dynamic simulations. In order to overcome this mismatch the Exploration Group at Technische Universität München (TUM) is developing a dynamic environmental simulation, the "Virtual Habitat" (V-HAB). The central element of this simulation is the dynamic and environmentally sensitive human model. The water subsystem simulation of the human model discussed in this paper is of vital importance for the efficiency of possible ECLSS optimizations, as an over- or under-scaled water subsystem would have an adverse effect on the overall mass budget. On the other hand water has a pivotal role in the human organism. Water accounts for about 60% of the total body mass and is educt and product of numerous metabolic reactions. It is a transport medium for solutes and, due to its high evaporation enthalpy, provides the most potent medium for heat load dissipation. In a system engineering approach the human water balance was worked out by simulating the human body's subsystems and their interactions. The body fluids were assumed to reside in three compartments: blood plasma, interstitial fluid and intracellular fluid. In addition, the active and passive transport of water and solutes between those

  1. Global neural dynamic surface tracking control of strict-feedback systems with application to hypersonic flight vehicle.

    Science.gov (United States)

    Xu, Bin; Yang, Chenguang; Pan, Yongping

    2015-10-01

    This paper studies both indirect and direct global neural control of strict-feedback systems in the presence of unknown dynamics, using the dynamic surface control (DSC) technique in a novel manner. A new switching mechanism is designed to combine an adaptive neural controller in the neural approximation domain, together with the robust controller that pulls the transient states back into the neural approximation domain from the outside. In comparison with the conventional control techniques, which could only achieve semiglobally uniformly ultimately bounded stability, the proposed control scheme guarantees all the signals in the closed-loop system are globally uniformly ultimately bounded, such that the conventional constraints on initial conditions of the neural control system can be relaxed. The simulation studies of hypersonic flight vehicle (HFV) are performed to demonstrate the effectiveness of the proposed global neural DSC design.

  2. Preparing for the crewed Mars journey: microbiota dynamics in the confined Mars500 habitat during simulated Mars flight and landing.

    Science.gov (United States)

    Schwendner, Petra; Mahnert, Alexander; Koskinen, Kaisa; Moissl-Eichinger, Christine; Barczyk, Simon; Wirth, Reinhard; Berg, Gabriele; Rettberg, Petra

    2017-10-04

    The Mars500 project was conceived as the first full duration simulation of a crewed return flight to Mars. For 520 days, six crew members lived confined in a specifically designed spacecraft mock-up. The herein described "MIcrobial ecology of Confined Habitats and humAn health" (MICHA) experiment was implemented to acquire comprehensive microbiota data from this unique, confined manned habitat, to retrieve important information on the occurring microbiota dynamics, the microbial load and diversity in the air and on various surfaces. In total, 360 samples from 20 (9 air, 11 surface) locations were taken at 18 time-points and processed by extensive cultivation, PhyloChip and next generation sequencing (NGS) of 16S rRNA gene amplicons. Cultivation assays revealed a Staphylococcus and Bacillus-dominated microbial community on various surfaces, with an average microbial load that did not exceed the allowed limits for ISS in-flight requirements indicating adequate maintenance of the facility. Areas with high human activity were identified as hotspots for microbial accumulation. Despite substantial fluctuation with respect to microbial diversity and abundance throughout the experiment, the location within the facility and the confinement duration were identified as factors significantly shaping the microbial diversity and composition, with the crew representing the main source for microbial dispersal. Opportunistic pathogens, stress-tolerant or potentially mobile element-bearing microorganisms were predicted to be prevalent throughout the confinement, while the overall microbial diversity dropped significantly over time. Our findings clearly indicate that under confined conditions, the community structure remains a highly dynamic system which adapts to the prevailing habitat and micro-conditions. Since a sterile environment is not achievable, these dynamics need to be monitored to avoid spreading of highly resistant or potentially pathogenic microorganisms and a

  3. Dynamic registration of an optical see-through HMD into a wide field-of-view rotorcraft flight simulation environment

    Science.gov (United States)

    Viertler, Franz; Hajek, Manfred

    2015-05-01

    To overcome the challenge of helicopter flight in degraded visual environments, current research considers headmounted displays with 3D-conformal (scene-linked) visual cues as most promising display technology. For pilot-in-theloop simulations with HMDs, a highly accurate registration of the augmented visual system is required. In rotorcraft flight simulators the outside visual cues are usually provided by a dome projection system, since a wide field-of-view (e.g. horizontally > 200° and vertically > 80°) is required, which can hardly be achieved with collimated viewing systems. But optical see-through HMDs do mostly not have an equivalent focus compared to the distance of the pilot's eye-point position to the curved screen, which is also dependant on head motion. Hence, a dynamic vergence correction has been implemented to avoid binocular disparity. In addition, the parallax error induced by even small translational head motions is corrected with a head-tracking system to be adjusted onto the projected screen. For this purpose, two options are presented. The correction can be achieved by rendering the view with yaw and pitch offset angles dependent on the deviating head position from the design eye-point of the spherical projection system. Furthermore, it can be solved by implementing a dynamic eye-point in the multi-channel projection system for the outside visual cues. Both options have been investigated for the integration of a binocular HMD into the Rotorcraft Simulation Environment (ROSIE) at the Technische Universitaet Muenchen. Pros and cons of both possibilities with regard on integration issues and usability in flight simulations will be discussed.

  4. Attitude dynamics and control of a spacecraft like a robotic manipulator when implementing on-orbit servicing

    Science.gov (United States)

    Da Fonseca, Ijar M.; Goes, Luiz C. S.; Seito, Narumi; da Silva Duarte, Mayara K.; de Oliveira, Élcio Jeronimo

    2017-08-01

    In space the manipulators working space is characterized by the microgravity environment. In this environment the spacecraft floats and its rotational/translational motion may be excited by any internal and external disturbances. The complete system, i.e., the spacecraft and the associated robotic manipulator, floats and is sensitive to any reaction force and torque related to the manipulator's operation. In this sense the effort done by the robot may result in torque about the system center of mass and also in forces changing its translational motion. This paper analyzes the impact of the robot manipulator dynamics on the attitude motion and the associated control effort to keep the attitude stable during the manipulator's operation. The dynamics analysis is performed in the close proximity phase of rendezvous docking/berthing operation. In such scenario the linear system equations for the translation and attitude relative motions are appropriate. The computer simulations are implemented for the relative translational and rotational motion. The equations of motion have been simulated through computer by using the MatLab software. The LQR and the PID control laws are used for linear and nonlinear control, respectively, aiming to keep the attitude stable while the robot is in and out of service. The gravity-gradient and the residual magnetic torque are considered as external disturbances. The control efforts are analyzed for the manipulator in and out of service. The control laws allow the system stabilization and good performance when the manipulator is in service.

  5. On the Fate of Debris Associated with the Disappearance of Flight MH370: a Dynamical System Perspective

    Science.gov (United States)

    Mancho, A. M.; Garcia-Garrido, V. J.; Wiggins, S.; Mendoza, C.

    2015-12-01

    The disappearance of Malaysia Airlines flight MH370 on the morning of the 8th of March 2014 is one of the great mysteries of our time. One relevant aspect of this mystery is that not a single piece of debris from the aircraft was found during the intensive surface search carried out in the months following the crash. Difficulties in the search efforts were due to the uncertainty in the plane's final impact point and the time passed since the accident and rise the question on how the debris was scattered in an always moving ocean, for which there exist multiple datasets that do not uniquely determine its state. Our approach to this problem is based on dynamical systems tools that identify dynamic barriers and coherent structures governing transport. By combining publicly available information supplied by different ocean data sources with these mathematical techniques, we are able to assess the spatio-temporal state of the ocean in the priority search area at the time of impact and the following weeks. Using this information we propose a revised search strategy by showing why one might not have expected to find debris in some large search areas targeted by the search services and determining regions where one might have expected impact debris to be located and that were not subjected to any exploration. This research has been supported by MINECO under grants MTM2014-56392-R and ICMAT Severo Ochoa project SEV-2011-0087 and ONR grant No. N00014- 01-1-0769. Computational support from CESGA is acknowledged. References [1] V. J. García-Garrido, A. M. Mancho, S. Wiggins, and C. Mendoza. A dynamical systems perspective on the absence of debris associated with the disappearance of flight MH370. Nonlin. Processes Geophys. Discuss., 2,1197-1225, doi:10.5194/npgd-2-1197-2015, 2015

  6. Quasi-dynamic mode of nanomembranes for time-of-flight mass spectrometry of proteins.

    Science.gov (United States)

    Park, Jonghoo; Kim, Hyunseok; Blick, Robert H

    2012-04-21

    Mechanical resonators realized on the nano-scale by now offer applications in mass-sensing of biomolecules with extraordinary sensitivity. The general idea is that perfect mechanical biosensors should be of extremely small size to achieve zeptogram sensitivity in weighing single molecules similar to a balance. However, the small scale and long response time of weighing biomolecules with a cantilever restrict their usefulness as a high-throughput method. Commercial mass spectrometry (MS) such as electro-spray ionization (ESI)-MS and matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF)-MS are the gold standards to which nanomechanical resonators have to live up to. These two methods rely on the ionization and acceleration of biomolecules and the following ion detection after a mass selection step, such as time-of-flight (TOF). Hence, the spectrum is typically represented in m/z, i.e. the mass to ionization charge ratio. Here, we describe the feasibility and mass range of detection of a new mechanical approach for ion detection in time-of-flight mass spectrometry, the principle of which is that the impinging ion packets excite mechanical oscillations in a silicon nitride nanomembrane. These mechanical oscillations are henceforth detected via field emission of electrons from the nanomembrane. Ion detection is demonstrated in MALDI-TOF analysis over a broad range with angiotensin, bovine serum albumin (BSA), and an equimolar protein mixture of insulin, BSA, and immunoglobulin G (IgG). We find an unprecedented mass range of operation of the nanomembrane detector.

  7. Application of Computational Fluid Dynamics (CFD) in transonic wind-tunnel/flight-test correlation

    Science.gov (United States)

    Murman, E. M.

    1982-01-01

    The capability for calculating transonic flows for realistic configurations and conditions is discussed. Various phenomena which were modeled are shown to have the same order of magnitude on the influence of predicted results. It is concluded that CFD can make the following contributions to the task of correlating wind tunnel and flight test data: some effects of geometry differences and aeroelastic distortion can be predicted; tunnel wall effects can be assessed and corrected for; and the effects of model support systems and free stream nonuniformities can be modeled.

  8. Attitude Design for the LADEE Mission

    Science.gov (United States)

    Galal, Ken; Nickel, Craig; Sherman, Ryan

    2015-01-01

    The Lunar Atmosphere and Dust Environment Explorer (LADEE) satellite successfully completed its 148-day science investigation in a low-altitude, near-equatorial lunar orbit on April 18, 2014. The LADEE spacecraft was built, managed and operated by NASA's Ames Research Center (ARC). The Mission Operations Center (MOC) was located at Ames and was responsible for activity planning, command sequencing, trajectory and attitude design, orbit determination, and spacecraft operations. The Science Operations Center (SOC) was located at Goddard Space Flight Center and was responsible for science planning, data archiving and distribution. This paper details attitude design and operations support for the LADEE mission. LADEE's attitude design was shaped by a wide range of instrument pointing requirements that necessitated regular excursions from the baseline one revolution per orbit "Ram" attitude. Such attitude excursions were constrained by a number of flight rules levied to protect instruments from the Sun, avoid geometries that would result in simultaneous occlusion of LADEE's two star tracker heads, and maintain the spacecraft within its thermal and power operating limits. To satisfy LADEE's many attitude requirements and constraints, a set of rules and conventions was adopted to manage the complexity of this design challenge and facilitate the automation of ground software that generated pointing commands spanning multiple days of operations at a time. The resulting LADEE Flight Dynamics System (FDS) that was developed used Visual Basic scripts that generated instructions to AGI's Satellite Tool Kit (STK) in order to derive quaternion commands at regular intervals that satisfied LADEE's pointing requirements. These scripts relied heavily on the powerful "align and constrain" capability of STK's attitude module to construct LADEE's attitude profiles and the slews to get there. A description of the scripts and the attitude modeling they embodied is provided. One particular

  9. Max Launch Abort System (MLAS) Pad Abort Test Vehicle (PATV) II Attitude Control System (ACS) Integration and Pressurization Subsystem Dynamic Random Vibration Analysis

    Science.gov (United States)

    Ekrami, Yasamin; Cook, Joseph S.

    2011-01-01

    In order to mitigate catastrophic failures on future generation space vehicles, engineers at the National Aeronautics and Space Administration have begun to integrate a novel crew abort systems that could pull a crew module away in case of an emergency at the launch pad or during ascent. The Max Launch Abort System (MLAS) is a recent test vehicle that was designed as an alternative to the baseline Orion Launch Abort System (LAS) to demonstrate the performance of a "tower-less" LAS configuration under abort conditions. The MLAS II test vehicle will execute a propulsive coast stabilization maneuver during abort to control the vehicles trajectory and thrust. To accomplish this, the spacecraft will integrate an Attitude Control System (ACS) with eight hypergolic monomethyl hydrazine liquid propulsion engines that are capable of operating in a quick pulsing mode. Two main elements of the ACS include a propellant distribution subsystem and a pressurization subsystem to regulate the flow of pressurized gas to the propellant tanks and the engines. The CAD assembly of the Attitude Control System (ACS) was configured and integrated into the Launch Abort Vehicle (LAV) design. A dynamic random vibration analysis was conducted on the Main Propulsion System (MPS) helium pressurization panels to assess the response of the panel and its components under increased gravitational acceleration loads during flight. The results indicated that the panels fundamental and natural frequencies were farther from the maximum Acceleration Spectral Density (ASD) vibrations which were in the range of 150-300 Hz. These values will direct how the components will be packaged in the vehicle to reduce the effects high gravitational loads.

  10. Flap-lag-torsional dynamics of helicopter rotor blades in forward flight

    Science.gov (United States)

    Crespodasilva, M. R. M.

    1986-01-01

    A perturbation/numerical methodology to analyze the flap-lead/lag motion of a centrally hinged spring restrained rotor blade that is valid for both hover and for forward flight was developed. The derivation of the nonlinear differential equations of motion and the analysis of the stability of the steady state response of the blade were conducted entirely in a Symbolics 3670 Machine using MACSYMA to perform all the lengthy symbolic manipulations. It also includes generation of the fortran codes and plots of the results. The Floquet theory was also applied to the differential equations of motion in order to compare results with those obtained from the perturbation analysis. The results obtained from the perturbation methodology and from Floquet theory were found to be very close to each other, which demonstrates the usefullness of the perturbation methodology. Another problem under study consisted in the analysis of the influence of higher order terms in the response and stability of a flexible rotor blade in forward flight using Computerized Symbolic Manipulation and a perturbation technique to bypass the Floquet theory. The derivation of the partial differential equations of motion is presented.

  11. Continuation Methods and Non-Linear/Non-Gaussian Estimation for Flight Dynamics, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose herein to augment current NASA spaceflight dynamics programs with algorithms and software from two domains. First, we propose to use numerical parameter...

  12. Continuation Methods and Non-Linear/Non-Gaussian Estimation for Flight Dynamics, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose herein to augment current NASA spaceflight dynamics programs with algorithms and software from three domains. First, we use parameter continuation methods...

  13. Convection measurement package for space processing sounding rocket flights. [low gravity manufacturing - fluid dynamics

    Science.gov (United States)

    Spradley, L. W.

    1975-01-01

    The effects on heated fluids of nonconstant accelerations, rocket vibrations, and spin rates, was studied. A system is discussed which can determine the influence of the convective effects on fluid experiments. The general suitability of sounding rockets for performing these experiments is treated. An analytical investigation of convection in an enclosure which is heated in low gravity is examined. The gravitational body force was taken as a time-varying function using anticipated sounding rocket accelerations, since accelerometer flight data were not available. A computer program was used to calculate the flow rates and heat transfer in fluids with geometries and boundary conditions typical of space processing configurations. Results of the analytical investigation identify the configurations, fluids and boundary values which are most suitable for measuring the convective environment of sounding rockets. A short description of fabricated fluid cells and the convection measurement package is given. Photographs are included.

  14. Precision Neutron Time-of-Flight Detectors Provide Insight into NIF Implosion Dynamics

    Science.gov (United States)

    Schlossberg, David; Eckart, M. J.; Grim, G. P.; Hartouni, E. P.; Hatarik, R.; Moore, A. S.; Waltz, C. S.

    2017-10-01

    During inertial confinement fusion, higher-order moments of neutron time-of-flight (nToF) spectra can provide essential information for optimizing implosions. The nToF diagnostic suite at the National Ignition Facility (NIF) was recently upgraded to include novel, quartz Cherenkov detectors. These detectors exploit the rapid Cherenkov radiation process, in contrast with conventional scintillator decay times, to provide high temporal-precision measurements that support higher-order moment analyses. Preliminary measurements have been made on the NIF during several implosions and initial results are presented here. Measured line-of-sight asymmetries, for example in ion temperatures, will be discussed. Finally, advanced detector optimization is shown to advance accessible physics, with possibilities for energy discrimination, gamma source identification, and further reduction in quartz response times. Work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

  15. Locomotion Dynamics for Bio-inspired Robots with Soft Appendages: Application to Flapping Flight and Passive Swimming

    Science.gov (United States)

    Boyer, Frédéric; Porez, Mathieu; Morsli, Ferhat; Morel, Yannick

    2017-08-01

    In animal locomotion, either in fish or flying insects, the use of flexible terminal organs or appendages greatly improves the performance of locomotion (thrust and lift). In this article, we propose a general unified framework for modeling and simulating the (bio-inspired) locomotion of robots using soft organs. The proposed approach is based on the model of Mobile Multibody Systems (MMS). The distributed flexibilities are modeled according to two major approaches: the Floating Frame Approach (FFA) and the Geometrically Exact Approach (GEA). Encompassing these two approaches in the Newton-Euler modeling formalism of robotics, this article proposes a unique modeling framework suited to the fast numerical integration of the dynamics of a MMS in both the FFA and the GEA. This general framework is applied on two illustrative examples drawn from bio-inspired locomotion: the passive swimming in von Karman Vortex Street, and the hovering flight with flexible flapping wings.

  16. Online Recorded Data-Based Composite Neural Control of Strict-Feedback Systems With Application to Hypersonic Flight Dynamics.

    Science.gov (United States)

    Xu, Bin; Yang, Daipeng; Shi, Zhongke; Pan, Yongping; Chen, Badong; Sun, Fuchun

    2017-09-25

    This paper investigates the online recorded data-based composite neural control of uncertain strict-feedback systems using the backstepping framework. In each step of the virtual control design, neural network (NN) is employed for uncertainty approximation. In previous works, most designs are directly toward system stability ignoring the fact how the NN is working as an approximator. In this paper, to enhance the learning ability, a novel prediction error signal is constructed to provide additional correction information for NN weight update using online recorded data. In this way, the neural approximation precision is highly improved, and the convergence speed can be faster. Furthermore, the sliding mode differentiator is employed to approximate the derivative of the virtual control signal, and thus, the complex analysis of the backstepping design can be avoided. The closed-loop stability is rigorously established, and the boundedness of the tracking error can be guaranteed. Through simulation of hypersonic flight dynamics, the proposed approach exhibits better tracking performance.

  17. Dynamic Tunnel Usability Study: Format Recommendations for Synthetic Vision System Primary Flight Displays

    Science.gov (United States)

    Arthur, Jarvis J., III; Prinzel, Lawrence J., III; Kramer, Lynda J.; Bailey, Randall E.

    2006-01-01

    A usability study evaluating dynamic tunnel concepts has been completed under the Aviation Safety and Security Program, Synthetic Vision Systems Project. The usability study was conducted in the Visual Imaging Simulator for Transport Aircraft Systems (VISTAS) III simulator in the form of questionnaires and pilot-in-the-loop simulation sessions. Twelve commercial pilots participated in the study to determine their preferences via paired comparisons and subjective rankings regarding the color, line thickness and sensitivity of the dynamic tunnel. The results of the study showed that color was not significant in pilot preference paired comparisons or in pilot rankings. Line thickness was significant for both pilot preference paired comparisons and in pilot rankings. The preferred line/halo thickness combination was a line width of 3 pixels and a halo of 4 pixels. Finally, pilots were asked their preference for the current dynamic tunnel compared to a less sensitive dynamic tunnel. The current dynamic tunnel constantly gives feedback to the pilot with regard to path error while the less sensitive tunnel only changes as the path error approaches the edges of the tunnel. The tunnel sensitivity comparison results were not statistically significant.

  18. Analyses of Magnetic Resonance Imaging of Cerebrospinal Fluid Dynamics Pre and Post Short and Long-Duration Space Flights

    Science.gov (United States)

    Alperin, Noam; Barr, Yael; Lee, Sang H.; Mason,Sara; Bagci, Ahmet M.

    2015-01-01

    Preliminary results are based on analyses of data from 17 crewmembers. The initial analysis compares pre to post-flight changes in total cerebral blood flow (CBF) and craniospinal CSF flow volume. Total CBF is obtained by summation of the mean flow rates through the 4 blood vessels supplying the brain (right and left internal carotid and vertebral arteries). Volumetric flow rates were obtained using an automated lumen segmentation technique shown to have 3-4-fold improved reproducibility and accuracy over manual lumen segmentation (6). Two cohorts, 5 short-duration and 8 long-duration crewmembers, who were scanned within 3 to 8 days post landing were included (4 short-duration crewmembers with MRI scans occurring beyond 10 days post flight were excluded). The VIIP Clinical Practice Guideline (CPG) classification is being used initially as a measure for VIIP syndrome severity. Median CPG scores of the short and long-duration cohorts were similar, 2. Mean preflight total CBF for the short and long-duration cohorts were similar, 863+/-144 and 747+/-119 mL/min, respectively. Percentage CBF changes for all short duration crewmembers were 11% or lower, within the range of normal physiological fluctuations in healthy individuals. In contrast, in 4 of the 8 long-duration crewmembers, the change in CBF exceeded the range of normal physiological fluctuation. In 3 of the 4 subjects an increase in CBF was measured. Large pre to post-flight changes in the craniospinal CSF flow volume were found in 6 of the 8 long-duration crewmembers. Box-Whisker plots of the CPG and the percent CBF and CSF flow changes for the two cohorts are shown in Figure 4. Examples of CSF flow waveforms for a short and two long-duration (CPG 0 and 3) are shown in Figure 5. Changes in CBF and CSF flow dynamics larger than normal physiological fluctuations were observed in the long-duration crewmembers. Changes in CSF flow were more pronounced than changes in CBF. Decreased CSF flow dynamics were observed

  19. Attitude Control Enhancement Using Distributed Wing Load Sensing for Dynamic Servoelastic Control, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Strain sensor information is used in nature to achieve robust flight, good rejection of wind disturbances, and stable head motion. Similar man-made sensing devices...

  20. Nonlinear robust control of hypersonic aircrafts with interactions between flight dynamics and propulsion systems.

    Science.gov (United States)

    Li, Zhaoying; Zhou, Wenjie; Liu, Hao

    2016-09-01

    This paper addresses the nonlinear robust tracking controller design problem for hypersonic vehicles. This problem is challenging due to strong coupling between the aerodynamics and the propulsion system, and the uncertainties involved in the vehicle dynamics including parametric uncertainties, unmodeled model uncertainties, and external disturbances. By utilizing the feedback linearization technique, a linear tracking error system is established with prescribed references. For the linear model, a robust controller is proposed based on the signal compensation theory to guarantee that the tracking error dynamics is robustly stable. Numerical simulation results are given to show the advantages of the proposed nonlinear robust control method, compared to the robust loop-shaping control approach. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  1. Modelling of Rigid-Body and Elastic Aircraft Dynamics for Flight Control Development.

    Science.gov (United States)

    1986-06-01

    AMAT MATSAV AUGMENT MI NV BMAT MMULT EVAL RLPLOT FASTCHG STABDER The subroutines are fairly well commented so that a person familiar with the theory...performed as in a typical flutter solution. C C Subroutine BMAT computes the B matrix from the forcing function C matrix Q. B is a function of dynamic...and BMAT multiplies matrices. C This is used to form the A and B matrices. C C Subroutine EVAL computes the eigenvalues of the A matrix C The

  2. Flight Dynamics Simulation Modeling and Control of a Large Flexible Tiltrotor Aircraft

    Science.gov (United States)

    2014-09-01

    analyses as it retains a momentum theory type rotor system. Later, CAMRAD, a comprehensive aeromechanics and dynamics model capa- ble of multi-rotor and...isotropic, linearly elastic material. 8. All blades are identical. 9. Euler- Bernoulli beam theory is used, implying plane cross sections remain plane and...aircraft could be improved to achieve a higher fidelity structural response. Currently, flexible wings are modeled as Bernoulli beams. Actual aircraft

  3. A dynamical systems perspective on the absence of debris associated with the disappearance of flight MH370

    Science.gov (United States)

    García-Garrido, V. J.; Mancho, A. M.; Wiggins, S.; Mendoza, C.

    2015-07-01

    The disappearance of Malaysia Airlines flight MH370 on the morning of the 8 March 2014 is one of the great mysteries of our time. Perhaps the most relevant aspect of this mystery is that not a single piece of debris from the aircraft has been found. Difficulties in the search efforts, due to the uncertainty in the plane's final impact point and the time that has passed since the accident, bring the question on how the debris has scattered in an always moving ocean, for which there are multiple data sets that do not uniquely determine its state. Our approach to this problem is based on the use of Lagrangian Descriptors (LD), a novel mathematical tool coming from dynamical systems theory that identifies dynamic barriers and coherent structures governing transport. By combining publicly available information supplied by different ocean data sources with these mathematical techniques, we are able to assess the spatio-temporal state of the ocean in the priority search area at the time of impact and the following weeks. Using this information we propose a revised search strategy by showing why one might not have expected to find debris in some large search areas targeted by the Australian Maritime Safety Authority (AMSA), and determining regions where one might have expected impact debris to be located and that have not been subjected to any exploration.

  4. A dynamical systems approach to the surface search for debris associated with the disappearance of flight MH370

    Science.gov (United States)

    García-Garrido, V. J.; Mancho, A. M.; Wiggins, S.; Mendoza, C.

    2015-11-01

    The disappearance of Malaysia Airlines flight MH370 on the morning of 8 March 2014 is one of the great mysteries of our time. Perhaps the most relevant aspect of this mystery is that not a single piece of debris from the aircraft was found during the intensive surface search carried out for roughly 2 months following the crash. Difficulties in the search efforts, due to the uncertainty of the plane's final impact point and the time that had passed since the accident, bring the question on how the debris scattered in an always moving ocean, for which there are multiple data sets that do not uniquely determine its state. Our approach to this problem is based on the use of Lagrangian descriptors (LD), a novel mathematical tool coming from dynamical systems theory that identifies dynamic barriers and coherent structures governing transport. By combining publicly available information supplied by different ocean data sources with these mathematical techniques, we are able to assess the spatio-temporal state of the ocean in the priority search area at the time of impact and the following weeks. Using this information we propose a revised search strategy by showing why one might not have expected to find debris in some large search areas targeted by the Australian Maritime Safety Authority (AMSA), and determining regions where one might have expected impact debris to be located, which were not subjected to any exploration.

  5. Fluid dynamics of flapping aquatic flight in the bird wrasse: three-dimensional unsteady computations with fin deformation.

    Science.gov (United States)

    Ramamurti, Ravi; Sandberg, William C; Löhner, Rainald; Walker, Jeffrey A; Westneat, Mark W

    2002-10-01

    Many fishes that swim with the paired pectoral fins use fin-stroke parameters that produce thrust force from lift in a mechanism of underwater flight. These locomotor mechanisms are of interest to behavioral biologists, biomechanics researchers and engineers. In the present study, we performed the first three-dimensional unsteady computations of fish swimming with oscillating and deforming fins. The objective of these computations was to investigate the fluid dynamics of force production associated with the flapping aquatic flight of the bird wrasse Gomphosus varius. For this computational work, we used the geometry of the wrasse and its pectoral fin, and previously measured fin kinematics, as the starting points for computational investigation of three-dimensional (3-D) unsteady fluid dynamics. We performed a 3-D steady computation and a complete set of 3-D quasisteady computations for a range of pectoral fin positions and surface velocities. An unstructured, grid-based, unsteady Navier-Stokes solver with automatic adaptive remeshing was then used to compute the unsteady flow about the wrasse through several complete cycles of pectoral fin oscillation. The shape deformation of the pectoral fin throughout the oscillation was taken from the experimental kinematics. The pressure distribution on the body of the bird wrasse and its pectoral fins was computed and integrated to give body and fin forces which were decomposed into lift and thrust. The velocity field variation on the surface of the wrasse body, on the pectoral fins and in the near-wake was computed throughout the swimming cycle. We compared our computational results for the steady, quasi-steady and unsteady cases with the experimental data on axial and vertical acceleration obtained from the pectoral fin kinematics experiments. These comparisons show that steady state computations are incapable of describing the fluid dynamics of flapping fins. Quasi-steady state computations, with correct incorporation of

  6. Variable Attitude Test Stand

    Data.gov (United States)

    Federal Laboratory Consortium — The Variable Attitude Test Stand designed and built for testing of the V-22 tilt rotor aircraft propulsion system, is used to evaluate the effect of aircraft flight...

  7. Reconfigurable Flight Control Using Nonlinear Dynamic Inversion with a Special Accelerometer Implementation

    Science.gov (United States)

    Bacon, Barton J.; Ostroff, Aaron J.

    2000-01-01

    This paper presents an approach to on-line control design for aircraft that have suffered either actuator failure, missing effector surfaces, surface damage, or any combination. The approach is based on a modified version of nonlinear dynamic inversion. The approach does not require a model of the baseline vehicle (effectors at zero deflection), but does require feedback of accelerations and effector positions. Implementation issues are addressed and the method is demonstrated on an advanced tailless aircraft. An experimental simulation analysis tool is used to directly evaluate the nonlinear system's stability robustness.

  8. Nonlinear Dynamic Inversion Baseline Control Law: Flight-Test Results for the Full-scale Advanced Systems Testbed F/A-18 Airplane

    Science.gov (United States)

    Miller, Christopher J.

    2011-01-01

    A model reference nonlinear dynamic inversion control law has been developed to provide a baseline controller for research into simple adaptive elements for advanced flight control laws. This controller has been implemented and tested in a hardware-in-the-loop simulation and in flight. The flight results agree well with the simulation predictions and show good handling qualities throughout the tested flight envelope with some noteworthy deficiencies highlighted both by handling qualities metrics and pilot comments. Many design choices and implementation details reflect the requirements placed on the system by the nonlinear flight environment and the desire to keep the system as simple as possible to easily allow the addition of the adaptive elements. The flight-test results and how they compare to the simulation predictions are discussed, along with a discussion about how each element affected pilot opinions. Additionally, aspects of the design that performed better than expected are presented, as well as some simple improvements that will be suggested for follow-on work.

  9. Dynamic Routing for Delay-Tolerant Networking in Space Flight Operations

    Science.gov (United States)

    Burleigh, Scott C.

    2008-01-01

    Contact Graph Routing (CGR) is a dynamic routing system that computes routes through a time-varying topology composed of scheduled, bounded communication contacts in a network built on the Delay-Tolerant Networking (DTN) architecture. It is designed to support operations in a space network based on DTN, but it also could be used in terrestrial applications where operation according to a predefined schedule is preferable to opportunistic communication, as in a low-power sensor network. This paper will describe the operation of the CGR system and explain how it can enable data delivery over scheduled transmission opportunities, fully utilizing the available transmission capacity, without knowing the current state of any bundle protocol node (other than the local node itself) and without exhausting processing resources at any bundle router.

  10. Modeling Attitude Dynamics in Simulink: A Study of the Rotational and Translational Motion of a Spacecraft Given Torques and Impulses Generated by RMS Hand Controllers

    Science.gov (United States)

    Mauldin, Rebecca H.

    2010-01-01

    In order to study and control the attitude of a spacecraft, it is necessary to understand the natural motion of a body in orbit. Assuming a spacecraft to be a rigid body, dynamics describes the complete motion of the vehicle by the translational and rotational motion of the body. The Simulink Attitude Analysis Model applies the equations of rigid body motion to the study of a spacecraft?s attitude in orbit. Using a TCP/IP connection, Matlab reads the values of the Remote Manipulator System (RMS) hand controllers and passes them to Simulink as specified torque and impulse profiles. Simulink then uses the governing kinematic and dynamic equations of a rigid body in low earth orbit (LE0) to plot the attitude response of a spacecraft for five seconds given known applied torques and impulses, and constant principal moments of inertia.

  11. Coupled Vortex-Lattice Flight Dynamic Model with Aeroelastic Finite-Element Model of Flexible Wing Transport Aircraft with Variable Camber Continuous Trailing Edge Flap for Drag Reduction

    Science.gov (United States)

    Nguyen, Nhan; Ting, Eric; Nguyen, Daniel; Dao, Tung; Trinh, Khanh

    2013-01-01

    This paper presents a coupled vortex-lattice flight dynamic model with an aeroelastic finite-element model to predict dynamic characteristics of a flexible wing transport aircraft. The aircraft model is based on NASA Generic Transport Model (GTM) with representative mass and stiffness properties to achieve a wing tip deflection about twice that of a conventional transport aircraft (10% versus 5%). This flexible wing transport aircraft is referred to as an Elastically Shaped Aircraft Concept (ESAC) which is equipped with a Variable Camber Continuous Trailing Edge Flap (VCCTEF) system for active wing shaping control for drag reduction. A vortex-lattice aerodynamic model of the ESAC is developed and is coupled with an aeroelastic finite-element model via an automated geometry modeler. This coupled model is used to compute static and dynamic aeroelastic solutions. The deflection information from the finite-element model and the vortex-lattice model is used to compute unsteady contributions to the aerodynamic force and moment coefficients. A coupled aeroelastic-longitudinal flight dynamic model is developed by coupling the finite-element model with the rigid-body flight dynamic model of the GTM.

  12. A Near-Hover Adaptive Attitude Control Strategy of a Ducted Fan Micro Aerial Vehicle with Actuator Dynamics

    Directory of Open Access Journals (Sweden)

    Shouzhao Sheng

    2015-09-01

    Full Text Available The aerodynamic parameters of ducted fan micro aerial vehicles (MAVs are difficult and expensive to precisely measure and are, therefore, not available in most cases. Furthermore, the actuator dynamics with risks of potentially destabilizing the overall system are important but often neglected consideration factors in the control system design of ducted fan MAVs. This paper presents a near-hover adaptive attitude control strategy of a prototype ducted fan MAV with actuator dynamics and without any prior information about the behavior of the MAV. The proposed strategy consists of an online parameter estimation algorithm and an adaptive gain scheduling algorithm, with the former accommodating parametric uncertainties, and the latter approximately eliminating the coupling among axes and guaranteeing the control quality of the MAV. The effectiveness of the proposed strategy is verified numerically and experimentally.

  13. Effective Assessments of Integrated Animations--Exploring Dynamic Physics Instruction for College Students' Learning and Attitudes

    Science.gov (United States)

    Su, King-Dow; Yeh, Shih-Chuan

    2014-01-01

    The purpose of this study was to give effective assessments of three major physics animations to upgrade college students' learning achievements and attitudes. All college participants were taken from mechanical and civil engineering departments who joined this physics course during the 2011 academic year. Three prime objectives of physics…

  14. Maneuver of Spinning Rocket in Flight

    OpenAIRE

    HAYAKAWA, Satio; ITO, Koji; MATSUI, Yutaka; NOGUCHI, Kunio; UESUGI, Kuninori; YAMASHITA, Kojun

    1980-01-01

    A Yo-despin device successfully functioned to change in flight the precession axis of a sounding rocket for astronomical observation. The rocket attitudes before and after yodespin were measured with a UV star sensor, an infrared horizon sensor and an infrared telescope. Instrumentation and performance of these devices as well as the attitude data during flight are described.

  15. Dynamics in γ-Fe2O3 nanoparticles studied by time-of-flight polarized neutron scattering

    DEFF Research Database (Denmark)

    Kuhn, L.T.; Lefmann, K.; Klausen, S.N.

    2004-01-01

    The inelastic neutron-scattering signal from magnetic nanoparticles contains information on magnetic dynamics like superparamagnetic relaxation and collective magnetic excitations. Often another, very broad quasi-elastic component is observed in addition. We have studied this quasi-elastic neutron...... signal from 4 nm ferrimagnetic maghemite (gamma-Fe(2)O(3)) particles, and by means of time-of-flight polarised neutron scattering we have identified the source of (most of) this signal to be water adsorbed at the surface of the nanoparticles. A minor part of the signal has its origin in dynamics...

  16. Paragliders flight dynamics

    OpenAIRE

    Diego Muniz Benedetti

    2012-01-01

    A prática do vôo de paraglider tem se popularizado nas últimas três décadas, e o desenvolvimento da tecnologia associada ao esporte resultou avanços consideráveis em termos de desempenho e segurança. Entretanto, devido à finalidade desportiva dessas aeronaves, ainda são raros os estudos científicos aplicados ao tema. Os avanços tecnológicos no projeto de paragliders devem-se principalmente aos esforços da indústria , sendo que, apesar de existirem diversos fabricantes com anos de experiência,...

  17. Design and Analysis of Morpheus Lander Flight Control System

    Science.gov (United States)

    Jang, Jiann-Woei; Yang, Lee; Fritz, Mathew; Nguyen, Louis H.; Johnson, Wyatt R.; Hart, Jeremy J.

    2014-01-01

    The Morpheus Lander is a vertical takeoff and landing test bed vehicle developed to demonstrate the system performance of the Guidance, Navigation and Control (GN&C) system capability for the integrated autonomous landing and hazard avoidance system hardware and software. The Morpheus flight control system design must be robust to various mission profiles. This paper presents a design methodology for employing numerical optimization to develop the Morpheus flight control system. The design objectives include attitude tracking accuracy and robust stability with respect to rigid body dynamics and propellant slosh. Under the assumption that the Morpheus time-varying dynamics and control system can be frozen over a short period of time, the flight controllers are designed to stabilize all selected frozen-time control systems in the presence of parametric uncertainty. Both control gains in the inner attitude control loop and guidance gains in the outer position control loop are designed to maximize the vehicle performance while ensuring robustness. The flight control system designs provided herein have been demonstrated to provide stable control systems in both Draper Ares Stability Analysis Tool (ASAT) and the NASA/JSC Trick-based Morpheus time domain simulation.

  18. Miracle Flights

    Science.gov (United States)

    ... a Flight Get Involved Events Shop Miles Contact Miracle Flights Blog Giving Tuesday 800-359-1711 Thousands of children have been saved, but we still have miles to go. Request a Flight Click Here to Donate - Your ...

  19. Small Satellite Passive Magnetic Attitude Control

    Science.gov (United States)

    Gerhardt, David T.

    Passive Magnetic Attitude Control (PMAC) is capable of aligning a satellite within 5 degrees of the local magnetic field at low resource cost, making it ideal for a small satellite. However, simulation attempts to date have not been able to predict the attitude dynamics at a level sufficient for mission design. Also, some satellites have suffered from degraded performance due to an incomplete understanding of PMAC system design. This dissertation alleviates these issues by discussing the design, inputs, and validation of PMAC systems for small satellites. Design rules for a PMAC system are defined using the Colorado Student Space Weather Experiment (CSSWE) CubeSat as an example. A Multiplicative Extended Kalman Filter (MEKF) is defined for the attitude determination of a PMAC satellite without a rate gyro. After on-orbit calibration of the off-the-shelf magnetometer and photodiodes and an on-orbit fit to the satellite magnetic moment, the MEKF regularly achieves a three sigma attitude uncertainty of 4 degrees or less. CSSWE is found to settle to the magnetic field in seven days, verifying its attitude design requirement. A Helmholtz cage is constructed and used to characterize the CSSWE bar magnet and hysteresis rods both individually and in the flight configuration. Fitted parameters which govern the magnetic material behavior are used as input to a PMAC dynamics simulation. All components of this simulation are described and defined. Simulation-based dynamics analysis shows that certain initial conditions result in abnormally decreased settling times; these cases may be identified by their dynamic response. The simulation output is compared to the MEKF output; the true dynamics are well modeled and the predicted settling time is found to possess a 20 percent error, a significant improvement over prior simulation.

  20. New Insights into the Molecular Dynamics of P3HT:PCBM Bulk Heterojunction: A Time-of-Flight Quasi-Elastic Neutron Scattering Study.

    Science.gov (United States)

    Guilbert, Anne A Y; Zbiri, Mohamed; Jenart, Maud V C; Nielsen, Christian B; Nelson, Jenny

    2016-06-16

    The molecular dynamics of organic semiconductor blend layers are likely to affect the optoelectronic properties and the performance of devices such as solar cells. We study the dynamics (5-50 ps) of the poly(3-hexylthiophene) (P3HT): phenyl-C61-butyric acid methyl ester (PCBM) blend by time-of-flight quasi-elastic neutron scattering, at temperatures in the range 250-360 K, thus spanning the glass transition temperature region of the polymer and the operation temperature of an OPV device. The behavior of the QENS signal provides evidence for the vitrification of P3HT upon blending, especially above the glass transition temperature, and the plasticization of PCBM by P3HT, both dynamics occurring on the picosecond time scale.

  1. Household-level dynamics of food waste production and related beliefs, attitudes, and behaviours in Guelph, Ontario

    International Nuclear Information System (INIS)

    Parizeau, Kate; Massow, Mike von; Martin, Ralph

    2015-01-01

    Highlights: • We combined household waste stream weights with survey data. • We examine relationships between waste and food-related practices and beliefs. • Families and large households produced more total waste, but less waste per capita. • Food awareness and waste awareness were related to reduced food waste. • Convenience lifestyles were differentially associated with food waste. - Abstract: It has been estimated that Canadians waste $27 billion of food annually, and that half of that waste occurs at the household level (Gooch et al., 2010). There are social, environmental, and economic implications for this scale of food waste, and source separation of organic waste is an increasingly common municipal intervention. There is relatively little research that assesses the dynamics of household food waste (particularly in Canada). The purpose of this study is to combine observations of organic, recyclable, and garbage waste production rates to survey results of food waste-related beliefs, attitudes, and behaviours at the household level in the mid-sized municipality of Guelph, Ontario. Waste weights and surveys were obtained from 68 households in the summer of 2013. The results of this study indicate multiple relationships between food waste production and household shopping practices, food preparation behaviours, household waste management practices, and food-related attitudes, beliefs, and lifestyles. Notably, we observed that food awareness, waste awareness, family lifestyles, and convenience lifestyles were related to food waste production. We conclude that it is important to understand the diversity of factors that can influence food wasting behaviours at the household level in order to design waste management systems and policies to reduce food waste

  2. Household-level dynamics of food waste production and related beliefs, attitudes, and behaviours in Guelph, Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Parizeau, Kate, E-mail: kate.parizeau@uoguelph.ca [Department of Geography, University of Guelph, Guelph, ON (Canada); Massow, Mike von [School of Hospitality, Food, and Tourism Management, University of Guelph, Guelph, ON (Canada); Martin, Ralph [Plant Agriculture Department, University of Guelph, Guelph, ON (Canada)

    2015-01-15

    Highlights: • We combined household waste stream weights with survey data. • We examine relationships between waste and food-related practices and beliefs. • Families and large households produced more total waste, but less waste per capita. • Food awareness and waste awareness were related to reduced food waste. • Convenience lifestyles were differentially associated with food waste. - Abstract: It has been estimated that Canadians waste $27 billion of food annually, and that half of that waste occurs at the household level (Gooch et al., 2010). There are social, environmental, and economic implications for this scale of food waste, and source separation of organic waste is an increasingly common municipal intervention. There is relatively little research that assesses the dynamics of household food waste (particularly in Canada). The purpose of this study is to combine observations of organic, recyclable, and garbage waste production rates to survey results of food waste-related beliefs, attitudes, and behaviours at the household level in the mid-sized municipality of Guelph, Ontario. Waste weights and surveys were obtained from 68 households in the summer of 2013. The results of this study indicate multiple relationships between food waste production and household shopping practices, food preparation behaviours, household waste management practices, and food-related attitudes, beliefs, and lifestyles. Notably, we observed that food awareness, waste awareness, family lifestyles, and convenience lifestyles were related to food waste production. We conclude that it is important to understand the diversity of factors that can influence food wasting behaviours at the household level in order to design waste management systems and policies to reduce food waste.

  3. Prediction of velocity and attitude of a yacht sailing upwind by computational fluid dynamics

    OpenAIRE

    Lee, Heebum; Park, Mi Yeon; Park, Sunho; Rhee, Shin Hyung

    2016-01-01

    One of the most important factors in sailing yacht design is accurate velocity prediction. Velocity prediction programs (VPP's) are widely used to predict velocity of sailing yachts. VPP's, which are primarily based on experimental data and experience of long years, however suffer limitations when applied in realistic conditions. Thus, in the present study, a high fidelity velocity prediction method using computational fluid dynamics (CFD) was proposed. Using the developed method, velocity an...

  4. Flight Planning in the Cloud

    Science.gov (United States)

    Flores, Sarah L.; Chapman, Bruce D.; Tung, Waye W.; Zheng, Yang

    2011-01-01

    This new interface will enable Principal Investigators (PIs), as well as UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) members to do their own flight planning and time estimation without having to request flight lines through the science coordinator. It uses an all-in-one Google Maps interface, a JPL hosted database, and PI flight requirements to design an airborne flight plan. The application will enable users to see their own flight plan being constructed interactively through a map interface, and then the flight planning software will generate all the files necessary for the flight. Afterward, the UAVSAR team can then complete the flight request, including calendaring and supplying requisite flight request files in the expected format for processing by NASA s airborne science program. Some of the main features of the interface include drawing flight lines on the map, nudging them, adding them to the current flight plan, and reordering them. The user can also search and select takeoff, landing, and intermediate airports. As the flight plan is constructed, all of its components are constantly being saved to the database, and the estimated flight times are updated. Another feature is the ability to import flight lines from previously saved flight plans. One of the main motivations was to make this Web application as simple and intuitive as possible, while also being dynamic and robust. This Web application can easily be extended to support other airborne instruments.

  5. Summary of the First High-Altitude, Supersonic Flight Dynamics Test for the Low-Density Supersonic Decelerator Project

    Science.gov (United States)

    Clark, Ian G.; Adler, Mark; Manning, Rob

    2015-01-01

    NASA's Low-Density Supersonic Decelerator Project is developing and testing the next generation of supersonic aerodynamic decelerators for planetary entry. A key element of that development is the testing of full-scale articles in conditions relevant to their intended use, primarily the tenuous Mars atmosphere. To achieve this testing, the LDSD project developed a test architecture similar to that used by the Viking Project in the early 1970's for the qualification of their supersonic parachute. A large, helium filled scientific balloon is used to hoist a 4.7 m blunt body test vehicle to an altitude of approximately 32 kilometers. The test vehicle is released from the balloon, spun up for gyroscopic stability, and accelerated to over four times the speed of sound and an altitude of 50 kilometers using a large solid rocket motor. Once at those conditions, the vehicle is despun and the test period begins. The first flight of this architecture occurred on June 28th of 2014. Though primarily a shake out flight of the new test system, the flight was also able to achieve an early test of two of the LDSD technologies, a large 6 m diameter Supersonic Inflatable Aerodynamic Decelerator (SIAD) and a large, 30.5 m nominal diameter supersonic parachute. This paper summarizes this first flight.

  6. A unified flight control methodology for a compound rotorcraft in fundamental and aerobatic maneuvering flight

    Science.gov (United States)

    Thorsen, Adam

    regime. An energy management system was developed in order to manage performance limits (namely power required) to promote carefree maneuvering and alleviate pilot workload. This system features limits on pilot commands and has additional logic for preserving control margins and limiting maximum speed in a dive. Nonlinear dynamic inversion (NLDI) is the framework of the unified controller, which incorporates primary and redundant controls. The inner loop of the NLDI controller regulates bank angle, pitch attitude, and yaw rate, while the outer loop command structure is varied (three modes). One version uses an outer loop that commands velocities in the longitudinal and vertical axes (velocity mode), another commands longitudinal acceleration and vertical speed (acceleration mode), and the third commands longitudinal acceleration and transitions from velocity to acceleration command in the vertical axis (aerobatic mode). The flight envelope is discretized into low, cruise, and high speed flight regimes. The unified outer loop primary control effectors for the longitudinal and vertical axes (collective pitch, pitch attitude, and propeller pitch) vary depending on flight regime. A weighted pseudoinverse is used to phase either the collective or propeller pitch in/out of a redundant control role. The controllers were evaluated in Penn State's Rotorcraft Flight Simulator retaining the cyclic stick for vertical and lateral axis control along with pedal inceptors for yaw axis control. A throttle inceptor was used in place of the pilot's traditional left hand inceptor for longitudinal axis control. Ultimately, a simple rigid body model of the aircraft was sufficient enough to design a controller with favorable performance and stability characteristics. This unified flight control system promoted a low enough pilot workload so that an untrained pilot (the author) was able to pilot maneuvers of varying complexity with ease. The framework of this unified system is generalized

  7. Attitudes and attitude change.

    Science.gov (United States)

    Bohner, Gerd; Dickel, Nina

    2011-01-01

    Attitudes and attitude change remain core topics of contemporary social psychology. This selective review emphasizes work published from 2005 to 2009. It addresses constructionist and stable-entity conceptualizations of attitude, the distinction between implicit and explicit measures of attitude, and implications of the foregoing for attitude change. Associative and propositional processes in attitude change are considered at a general level and in relation to evaluative conditioning. The role of bodily states and physical perceptions in attitude change is reviewed. This is followed by an integrative perspective on processing models of persuasion and the consideration of meta-cognitions in persuasion. Finally, effects of attitudes on information processing, social memory, and behavior are highlighted. Core themes cutting across the areas reviewed are attempts at integrative theorizing bringing together formerly disparate phenomena and viewpoints.

  8. Design, dynamics and control of an Adaptive Singularity-Free Control Moment Gyroscope actuator for microspacecraft Attitude Determination and Control System

    Science.gov (United States)

    Viswanathan, Sasi Prabhakaran

    Design, dynamics, control and implementation of a novel spacecraft attitude control actuator called the "Adaptive Singularity-free Control Moment Gyroscope" (ASCMG) is presented in this dissertation. In order to construct a comprehensive attitude dynamics model of a spacecraft with internal actuators, the dynamics of a spacecraft with an ASCMG, is obtained in the framework of geometric mechanics using the principles of variational mechanics. The resulting dynamics is general and complete model, as it relaxes the simplifying assumptions made in prior literature on Control Moment Gyroscopes (CMGs) and it also addresses the adaptive parameters in the dynamics formulation. The simplifying assumptions include perfect axisymmetry of the rotor and gimbal structures, perfect alignment of the centers of mass of the gimbal and the rotor etc. These set of simplifying assumptions imposed on the design and dynamics of CMGs leads to adverse effects on their performance and results in high manufacturing cost. The dynamics so obtained shows the complex nonlinear coupling between the internal degrees of freedom associated with an ASCMG and the spacecraft bus's attitude motion. By default, the general ASCMG cluster can function as a Variable Speed Control Moment Gyroscope, and reduced to function in CMG mode by spinning the rotor at constant speed, and it is shown that even when operated in CMG mode, the cluster can be free from kinematic singularities. This dynamics model is then extended to include the effects of multiple ASCMGs placed in the spacecraft bus, and sufficient conditions for non-singular ASCMG cluster configurations are obtained to operate the cluster both in VSCMG and CMG modes. The general dynamics model of the ASCMG is then reduced to that of conventional VSCMGs and CMGs by imposing the standard set of simplifying assumptions used in prior literature. The adverse effects of the simplifying assumptions that lead to the complexities in conventional CMG design, and

  9. Attitudes and attitude change

    DEFF Research Database (Denmark)

    Scholderer, Joachim

    2010-01-01

    An attitude can be defined as the evaluation of an object as positive or negative. The term "object" in this definition should be understood in a broad sense; an attitude object may be any concrete or abstract entity that is in some way represented in our thoughts and memory. In other words......, attitude objects are simply the things we like or dislike. Consumer researchers are mainly interested in attitude objects of two classes, products and services, including the attributes, issues, persons, communications, situations, and behaviours related to them. Research on consumer attitudes takes two...... perspectives: Understanding attitude structure: how is an attitude cognitively represented in a consumer's mind, including its components (intra-attitudinal structure) and its associations with other psychological variables (inter-attitudinal structure)? Understanding information processing: what...

  10. Attitudes and Attitude Change.

    Science.gov (United States)

    Albarracin, Dolores; Shavitt, Sharon

    2018-01-04

    This review covers research on attitudes and attitude change published between 2010 and 2017. We characterize this period as one of significant progress toward an understanding of how attitudes form and change in three critical contexts. The first context is the person, as attitudes change in connection to values, general goals, language, emotions, and human development. The second context is social relationships, which link attitude change to the communicator of persuasive messages, social media, and culture. The third context is sociohistorical and highlights the influence of unique events, including sociopolitical, economic, and climatic occurrences. In conclusion, many important recent findings reflect the fact that holism, with a focus on situating attitudes within their personal, social, and historical contexts, has become the zeitgeist of attitude research during this period.

  11. MinXSS-1 CubeSat On-Orbit Pointing and Power Performance: The First Flight of the Blue Canyon Technologies XACT 3-axis Attitude Determination and Control System

    Science.gov (United States)

    Mason, James Paul; Baumgart, Matt; Rogler, Bryan; Downs, Chloe; Williams, Margaret; Woods, Thomas N.; Palo, Scott; Chamberlin, Phillip C.; Solomon, Stanley; Jones, Andrew; Li, Xinlin; Kohnert, Rick; Caspi, Amir

    2017-12-01

    The Miniature X-ray Solar Spectrometer (MinXSS) is a three-unit (3U) CubeSat designed for a three-month mission to study solar soft X-ray spectral irradiance. The first of the two flight models was deployed from the International Space Station in May 2016, and operated for one year before its natural deorbiting. This was the first flight of the Blue Canyon Technologies XACT 3-axis attitude determination and control system - a commercially available, high-precision pointing system. The performance of the pointing system on orbit was characterized, including performance at low altitudes where drag torque builds up. It was found that the pointing accuracy was 0.0042° - 0.0117° (15" - 42", 3σ, axis dependent) consistently from 190 km - 410 km, slightly better than the specification sheet states. Peak-to-peak jitter was estimated to be 0.0073° (10 s^-1) - 0.0183° (10 s^-1) (26" (10 s^-1) - 66" (10 s^-1), 3σ). The system was capable of dumping mome ntum until an altitude of 185 km. Small amounts of sensor degradation were found in the star tracker and coarse sun sensor. The mission profile did not require high-agility maneuvers, so it was not possible to characterize this metric. Without a GPS receiver, it was necessary to periodically upload ephemeris information to update the orbit propagation model and maintain pointing. At 400 km, these uploads were required once every other week; at ˜270 km, they were required every day. The power performance of the electric power system was also characterized, including use of a novel pseudo-peak power tracker - a resistor that limited the current draw from the battery on the solar panels. With 19 30% efficient solar cells and an 8 W system load, the power balance had 65% of margin on orbit. The current paper presents several recommendations to other CubeSat programs throughout.

  12. Lift calculations based on accepted wake models for animal flight are inconsistent and sensitive to vortex dynamics.

    Science.gov (United States)

    Gutierrez, Eric; Quinn, Daniel B; Chin, Diana D; Lentink, David

    2016-12-06

    There are three common methods for calculating the lift generated by a flying animal based on the measured airflow in the wake. However, these methods might not be accurate according to computational and robot-based studies of flapping wings. Here we test this hypothesis for the first time for a slowly flying Pacific parrotlet in still air using stereo particle image velocimetry recorded at 1000 Hz. The bird was trained to fly between two perches through a laser sheet wearing laser safety goggles. We found that the wingtip vortices generated during mid-downstroke advected down and broke up quickly, contradicting the frozen turbulence hypothesis typically assumed in animal flight experiments. The quasi-steady lift at mid-downstroke was estimated based on the velocity field by applying the widely used Kutta-Joukowski theorem, vortex ring model, and actuator disk model. The calculated lift was found to be sensitive to the applied model and its different parameters, including vortex span and distance between the bird and laser sheet-rendering these three accepted ways of calculating weight support inconsistent. The three models predict different aerodynamic force values mid-downstroke compared to independent direct measurements with an aerodynamic force platform that we had available for the same species flying over a similar distance. Whereas the lift predictions of the Kutta-Joukowski theorem and the vortex ring model stayed relatively constant despite vortex breakdown, their values were too low. In contrast, the actuator disk model predicted lift reasonably accurately before vortex breakdown, but predicted almost no lift during and after vortex breakdown. Some of these limitations might be better understood, and partially reconciled, if future animal flight studies report lift calculations based on all three quasi-steady lift models instead. This would also enable much needed meta studies of animal flight to derive bioinspired design principles for quasi-steady lift

  13. A dynamical systems approach to the surface search for debris associated with the disappearance of flight MH370

    OpenAIRE

    V. J. García-Garrido; A. M. Mancho; S. Wiggins; C. Mendoza

    2015-01-01

    The disappearance of Malaysia Airlines flight MH370 on the morning of 8 March 2014 is one of the great mysteries of our time. Perhaps the most relevant aspect of this mystery is that not a single piece of debris from the aircraft was found during the intensive surface search carried out for roughly 2 months following the crash. Difficulties in the search efforts, due to the uncertainty of the plane's final impact point and the time that had passed since the accident, bring the question on how...

  14. Laser Tracker Utilization Methodology in Measuring Truth Trajectories for INS Testing on 6 Degree of Freedom Table at the Marshall Space Flight Center's Contact Dynamics Simulation Laboratory with Lessons Learned

    Science.gov (United States)

    Leggett, Jared O.; Bryant, Thomas C.; Cowen, Charles T.; Clifton, Billy W.

    2018-01-01

    When performing Inertial Navigation System (INS) testing at the Marshall Space Flight Center's (MSFC) Contact Dynamics Simulation Laboratory (CDSL) early in 2017, a Leica Geosystems AT901 Laser Tracker system (LLT) measured the twist & sway trajectories as generated by the 6 Degree Of Freedom (6DOF) Table in the CDSL. These LLT measured trajectories were used in the INS software model validation effort. Several challenges were identified and overcome during the preparation for the INS testing, as well as numerous lessons learned. These challenges included determining the position and attitude of the LLT with respect to an INS-shared coordinate frame using surveyed monument locations in the CDSL and the accompanying mathematical transformation, accurately measuring the spatial relationship between the INS and a 6DOF tracking probe due to lack of INS visibility from the LLT location, obtaining the data from the LLT during a test, determining how to process the results for comparison with INS data in time and frequency domains, and using a sensitivity analysis of the results to verify the quality of the results. While many of these challenges were identified and overcome before or during testing, a significant lesson on test set-up was not learned until later in the data analysis process. It was found that a combination of trajectory-dependent gimbal locking and environmental noise introduced non-negligible noise in the angular measurements of the LLT that spanned the evaluated frequency spectrum. The lessons learned in this experiment may be useful for others performing INS testing in similar testing facilities.

  15. Aerodynamic Reconstruction Applied to Parachute Test Vehicle Flight Data Analysis

    Science.gov (United States)

    Cassady, Leonard D.; Ray, Eric S.; Truong, Tuan H.

    2013-01-01

    The aerodynamics, both static and dynamic, of a test vehicle are critical to determining the performance of the parachute cluster in a drop test and for conducting a successful test. The Capsule Parachute Assembly System (CPAS) project is conducting tests of NASA's Orion Multi-Purpose Crew Vehicle (MPCV) parachutes at the Army Yuma Proving Ground utilizing the Parachute Test Vehicle (PTV). The PTV shape is based on the MPCV, but the height has been reduced in order to fit within the C-17 aircraft for extraction. Therefore, the aerodynamics of the PTV are similar, but not the same as, the MPCV. A small series of wind tunnel tests and computational fluid dynamics cases were run to modify the MPCV aerodynamic database for the PTV, but aerodynamic reconstruction of the flights has proven an effective source for further improvements to the database. The acceleration and rotational rates measured during free flight, before parachute inflation but during deployment, were used to con rm vehicle static aerodynamics. A multibody simulation is utilized to reconstruct the parachute portions of the flight. Aerodynamic or parachute parameters are adjusted in the simulation until the prediction reasonably matches the flight trajectory. Knowledge of the static aerodynamics is critical in the CPAS project because the parachute riser load measurements are scaled based on forebody drag. PTV dynamic damping is critical because the vehicle has no reaction control system to maintain attitude - the vehicle dynamics must be understood and modeled correctly before flight. It will be shown here that aerodynamic reconstruction has successfully contributed to the CPAS project.

  16. DRIRU I/SKIRU - The application of the DTG to spacecraft attitude control. [Dynamically-Tuned Gyro for Inertial Reference Unit systems

    Science.gov (United States)

    Swanson, C. O.

    1982-01-01

    The dynamically tuned gyro (DTG) was developed to replace the floated, rate integrating gyro used for space attitude control, as the DTG fulfills cost, performance, and reliability requirements not satisfied by its predecessor. The use of this gyro in the Dry Gyro Inertial Reference Unit I (DRIRU I) marked the first application of a DTG in a spacecraft attitude reference unit. Design and performance characteristics of DTG application in the Singer-Kearfott Inertial Reference Unit (SKIRU) are outlined, for example its minimal weight (7 lb), and operational reliability. The DTG has accomplished 156,000 failure-free hours, and a chart, logging test performance, indicates that this and other requirements were more than sufficiently satisfied. The unit has an unparalleled life span, with several units still operating after 70,000 to 130,000 hours, and a random drift which always remains under 0.0005 deg/h. Potential for improvements, such as drift performance, are considered.

  17. An integrated ion trap and time-of-flight mass spectrometer for chemical and photo- reaction dynamics studies.

    Science.gov (United States)

    Schowalter, Steven J; Chen, Kuang; Rellergert, Wade G; Sullivan, Scott T; Hudson, Eric R

    2012-04-01

    We demonstrate the integration of a linear quadrupole trap with a simple time-of-flight mass spectrometer with medium-mass resolution (m/Δm ∼ 50) geared towards the demands of atomic, molecular, and chemical physics experiments. By utilizing a novel radial ion extraction scheme from the linear quadrupole trap into the mass analyzer, a device with large trap capacity and high optical access is realized without sacrificing mass resolution. This provides the ability to address trapped ions with laser light and facilitates interactions with neutral background gases prior to analyzing the trapped ions. Here, we describe the construction and implementation of the device as well as present representative ToF spectra. We conclude by demonstrating the flexibility of the device with proof-of-principle experiments that include the observation of molecular-ion photodissociation and the measurement of trapped-ion chemical reaction rates. © 2012 American Institute of Physics

  18. An integrated ion trap and time-of-flight mass spectrometer for chemical and photo- reaction dynamics studies

    International Nuclear Information System (INIS)

    Schowalter, Steven J.; Chen Kuang; Rellergert, Wade G.; Sullivan, Scott T.; Hudson, Eric R.

    2012-01-01

    We demonstrate the integration of a linear quadrupole trap with a simple time-of-flight mass spectrometer with medium-mass resolution (m/Δm∼ 50) geared towards the demands of atomic, molecular, and chemical physics experiments. By utilizing a novel radial ion extraction scheme from the linear quadrupole trap into the mass analyzer, a device with large trap capacity and high optical access is realized without sacrificing mass resolution. This provides the ability to address trapped ions with laser light and facilitates interactions with neutral background gases prior to analyzing the trapped ions. Here, we describe the construction and implementation of the device as well as present representative ToF spectra. We conclude by demonstrating the flexibility of the device with proof-of-principle experiments that include the observation of molecular-ion photodissociation and the measurement of trapped-ion chemical reaction rates.

  19. Ongoing Analyses of Rocket Based Combined Cycle Engines by the Applied Fluid Dynamics Analysis Group at Marshall Space Flight Center

    Science.gov (United States)

    Ruf, Joseph H.; Holt, James B.; Canabal, Francisco

    2001-01-01

    This paper presents the status of analyses on three Rocket Based Combined Cycle (RBCC) configurations underway in the Applied Fluid Dynamics Analysis Group (TD64). TD64 is performing computational fluid dynamics (CFD) analysis on a Penn State RBCC test rig, the proposed Draco axisymmetric RBCC engine and the Trailblazer engine. The intent of the analysis on the Penn State test rig is to benchmark the Finite Difference Navier Stokes (FDNS) code for ejector mode fluid dynamics. The Draco analysis was a trade study to determine the ejector mode performance as a function of three engine design variables. The Trailblazer analysis is to evaluate the nozzle performance in scramjet mode. Results to date of each analysis are presented.

  20. Ongoing Analysis of Rocket Based Combined Cycle Engines by the Applied Fluid Dynamics Analysis Group at Marshall Space Flight Center

    Science.gov (United States)

    Ruf, Joseph; Holt, James B.; Canabal, Francisco

    1999-01-01

    This paper presents the status of analyses on three Rocket Based Combined Cycle configurations underway in the Applied Fluid Dynamics Analysis Group (TD64). TD64 is performing computational fluid dynamics analysis on a Penn State RBCC test rig, the proposed Draco axisymmetric RBCC engine and the Trailblazer engine. The intent of the analysis on the Penn State test rig is to benchmark the Finite Difference Navier Stokes code for ejector mode fluid dynamics. The Draco engine analysis is a trade study to determine the ejector mode performance as a function of three engine design variables. The Trailblazer analysis is to evaluate the nozzle performance in scramjet mode. Results to date of each analysis are presented.

  1. Assessing Regional Attitudes about Entrepreneurship

    OpenAIRE

    Loveridge, Scott; Miller, Steven R.; Komarek, Timothy M.; Satimanon, Thasanee

    2012-01-01

    Much of the current discussion on factors that influence entrepreneurial activity focuses on availability of human, social, and financial capitals, regional economic conditions, and dynamics of population. We discuss social attitudes toward entrepreneurship and how attitudes may influence entrepreneurial activity. We analyze telephone survey questions designed to gauge attitudes towards community entrepreneurship. High school entrepreneurship career exploration and positive spin-offs from loc...

  2. Earth Observing System (EOS) Aqua Launch and Early Mission Attitude Support Experiences

    Science.gov (United States)

    Tracewell, D.; Glickman, J.; Hashmall, J.; Natanson, G.; Sedlak, J.

    2003-01-01

    The Earth Observing System (EOS) Aqua satellite was successfully launched on May 4,2002. Aqua is the second in the series of EOS satellites. EOS is part of NASA s Earth Science Enterprise Program, whose goals are to advance the scientific understanding of the Earth system. Aqua is a three-axis stabilized, Earth-pointing spacecraft in a nearly circular, sun-synchronous orbit at an altitude of 705 km. The Goddard Space Flight Center (GSFC) Flight Dynamics attitude team supported all phases of the launch and early mission. This paper presents the main results and lessons learned during this period, including: real-time attitude mode transition support, sensor calibration, onboard computer attitude validation, response to spacecraft emergencies, postlaunch attitude analyses, and anomaly resolution. In particular, Flight Dynamics support proved to be invaluable for successful Earth acquisition, fine-point mode transition, and recognition and correction of several anomalies, including support for the resolution of problems observed with the MODIS instrument.

  3. Impact of time-of-flight on indirect 3D and direct 4D parametric image reconstruction in the presence of inconsistent dynamic PET data

    Science.gov (United States)

    Kotasidis, F. A.; Mehranian, A.; Zaidi, H.

    2016-05-01

    Kinetic parameter estimation in dynamic PET suffers from reduced accuracy and precision when parametric maps are estimated using kinetic modelling following image reconstruction of the dynamic data. Direct approaches to parameter estimation attempt to directly estimate the kinetic parameters from the measured dynamic data within a unified framework. Such image reconstruction methods have been shown to generate parametric maps of improved precision and accuracy in dynamic PET. However, due to the interleaving between the tomographic and kinetic modelling steps, any tomographic or kinetic modelling errors in certain regions or frames, tend to spatially or temporally propagate. This results in biased kinetic parameters and thus limits the benefits of such direct methods. Kinetic modelling errors originate from the inability to construct a common single kinetic model for the entire field-of-view, and such errors in erroneously modelled regions could spatially propagate. Adaptive models have been used within 4D image reconstruction to mitigate the problem, though they are complex and difficult to optimize. Tomographic errors in dynamic imaging on the other hand, can originate from involuntary patient motion between dynamic frames, as well as from emission/transmission mismatch. Motion correction schemes can be used, however, if residual errors exist or motion correction is not included in the study protocol, errors in the affected dynamic frames could potentially propagate either temporally, to other frames during the kinetic modelling step or spatially, during the tomographic step. In this work, we demonstrate a new strategy to minimize such error propagation in direct 4D image reconstruction, focusing on the tomographic step rather than the kinetic modelling step, by incorporating time-of-flight (TOF) within a direct 4D reconstruction framework. Using ever improving TOF resolutions (580 ps, 440 ps, 300 ps and 160 ps), we demonstrate that direct 4D TOF image

  4. Experimental Analysis of the Vorticity and Turbulent Flow Dynamics of a Pitching Airfoil at Realistic Flight Conditions

    Science.gov (United States)

    2007-08-31

    Element type Hex, independent meshing, Linear 3D stress Hex, independent meshing, Linear 3D stress 1 English Units were used in ABAQUS The NACA...Flow Freestream Condition Instrumentation Test section conditions were measured using a Druck DPI 203 digital pressure gage and an Omega Model 199...temperature gage. The Druck pressure gage measures the set dynamic pressure within 0.08%± of full scale, and the Omega thermometer is accurate to

  5. Small Body GN and C Research Report: G-SAMPLE - An In-Flight Dynamical Method for Identifying Sample Mass [External Release Version

    Science.gov (United States)

    Carson, John M., III; Bayard, David S.

    2006-01-01

    G-SAMPLE is an in-flight dynamical method for use by sample collection missions to identify the presence and quantity of collected sample material. The G-SAMPLE method implements a maximum-likelihood estimator to identify the collected sample mass, based on onboard force sensor measurements, thruster firings, and a dynamics model of the spacecraft. With G-SAMPLE, sample mass identification becomes a computation rather than an extra hardware requirement; the added cost of cameras or other sensors for sample mass detection is avoided. Realistic simulation examples are provided for a spacecraft configuration with a sample collection device mounted on the end of an extended boom. In one representative example, a 1000 gram sample mass is estimated to within 110 grams (95% confidence) under realistic assumptions of thruster profile error, spacecraft parameter uncertainty, and sensor noise. For convenience to future mission design, an overall sample-mass estimation error budget is developed to approximate the effect of model uncertainty, sensor noise, data rate, and thrust profile error on the expected estimate of collected sample mass.

  6. Lattice dynamics approach to determine the dependence of the time-of-flight of transversal polarized acoustic waves on external stress

    Science.gov (United States)

    Tarar, K. S.; Pluta, M.; Amjad, U.; Grill, W.

    2011-04-01

    Based on the lattice dynamics approach the dependence of the time-of-flight (TOF) on stress has been modeled for transversal polarized acoustic waves. The relevant dispersion relation is derived from the appropriate mass-spring model together with the dependencies on the restoring forces including the effect of externally applied stress. The lattice dynamics approach can also be interpreted as a discrete and strictly periodic lumped circuit. In that case the modeling represents a finite element approach. In both cases the properties relevant for wavelengths large with respect to the periodic structure can be derived from the respective limit relating also to low frequencies. The model representing a linear chain with stiffness to shear and additional stiffness introduced by extensional stress is presented and compared to existing models, which so far represent each only one of the effects treated here in combination. For a string this effect is well known from musical instruments. The counteracting effects are discussed and compared to experimental results.

  7. Flight Planning

    Science.gov (United States)

    1991-01-01

    Seagull Technology, Inc., Sunnyvale, CA, produced a computer program under a Langley Research Center Small Business Innovation Research (SBIR) grant called STAFPLAN (Seagull Technology Advanced Flight Plan) that plans optimal trajectory routes for small to medium sized airlines to minimize direct operating costs while complying with various airline operating constraints. STAFPLAN incorporates four input databases, weather, route data, aircraft performance, and flight-specific information (times, payload, crew, fuel cost) to provide the correct amount of fuel optimal cruise altitude, climb and descent points, optimal cruise speed, and flight path.

  8. Velocity-Aided Attitude Estimation for Helicopter Aircraft Using Microelectromechanical System Inertial-Measurement Units

    Directory of Open Access Journals (Sweden)

    Sang Cheol Lee

    2016-12-01

    Full Text Available This paper presents an algorithm for velocity-aided attitude estimation for helicopter aircraft using a microelectromechanical system inertial-measurement unit. In general, high- performance gyroscopes are used for estimating the attitude of a helicopter, but this type of sensor is very expensive. When designing a cost-effective attitude system, attitude can be estimated by fusing a low cost accelerometer and a gyro, but the disadvantage of this method is its relatively low accuracy. The accelerometer output includes a component that occurs primarily as the aircraft turns, as well as the gravitational acceleration. When estimating attitude, the accelerometer measurement terms other than gravitational ones can be considered as disturbances. Therefore, errors increase in accordance with the flight dynamics. The proposed algorithm is designed for using velocity as an aid for high accuracy at low cost. It effectively eliminates the disturbances of accelerometer measurements using the airspeed. The algorithm was verified using helicopter experimental data. The algorithm performance was confirmed through a comparison with an attitude estimate obtained from an attitude heading reference system based on a high accuracy optic gyro, which was employed as core attitude equipment in the helicopter.

  9. Velocity-Aided Attitude Estimation for Helicopter Aircraft Using Microelectromechanical System Inertial-Measurement Units

    Science.gov (United States)

    Lee, Sang Cheol; Hong, Sung Kyung

    2016-01-01

    This paper presents an algorithm for velocity-aided attitude estimation for helicopter aircraft using a microelectromechanical system inertial-measurement unit. In general, high- performance gyroscopes are used for estimating the attitude of a helicopter, but this type of sensor is very expensive. When designing a cost-effective attitude system, attitude can be estimated by fusing a low cost accelerometer and a gyro, but the disadvantage of this method is its relatively low accuracy. The accelerometer output includes a component that occurs primarily as the aircraft turns, as well as the gravitational acceleration. When estimating attitude, the accelerometer measurement terms other than gravitational ones can be considered as disturbances. Therefore, errors increase in accordance with the flight dynamics. The proposed algorithm is designed for using velocity as an aid for high accuracy at low cost. It effectively eliminates the disturbances of accelerometer measurements using the airspeed. The algorithm was verified using helicopter experimental data. The algorithm performance was confirmed through a comparison with an attitude estimate obtained from an attitude heading reference system based on a high accuracy optic gyro, which was employed as core attitude equipment in the helicopter. PMID:27973429

  10. Dynamics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Dynamics Lab replicates vibration environments for every Navy platform. Testing performed includes: Flight Clearance, Component Improvement, Qualification, Life...

  11. Attitudes and persuasion.

    Science.gov (United States)

    Crano, William D; Prislin, Radmila

    2006-01-01

    Study of attitudes and persuasion remains a defining characteristic of contemporary social psychology. This review outlines recent advances, with emphasis on the relevance of today's work for perennial issues. We reiterate the distinction between attitude formation and change, and show its relevance for persuasion. Single- and dual-process models are discussed, as are current views on dissonance theory. Majority and minority influence are scrutinized, with special emphasis on integrative theoretical innovations. Attitude strength is considered, and its relevance to ambivalence and resistance documented. Affect, mood, and emotion effects are reviewed, especially as they pertain to fear arousal and (un)certainty. Finally, we discuss attitude-behavior consistency, perhaps the reason for our interest in attitudes in the first place, with emphasis on self-interest and the theory of planned behavior. Our review reflects the dynamism and the reach of the area, and suggests a sure and sometimes rapid accumulation of knowledge and understanding.

  12. Flight and Stability of a Laser Inertial Fusion Energy Target in the Drift Region between Injection and the Reaction Chamber with Computational Fluid Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Mitori, T. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)

    2013-12-01

    A Laser Inertial Fusion Energy (LIFE) target’s flight through a low Reynolds number and high Mach number regime was analyzed with computational fluid dynamics software. This regime consisted of xenon gas at 1,050 K and approximately 6,670 Pa. Simulations with similar flow conditions were performed with a sphere and compared with experimental data and published correlations for validation purposes. Transient considerations of the developing flow around the target were explored. Simulations of the target at different velocities were used to determine correlations for the drag coefficient and Nusselt number as functions of the Reynolds number. Simulations with different angles of attack were used to determine the aerodynamic coefficients of drag, lift, Magnus moment, and overturning moment as well as target stability. The drag force, lift force, and overturning moment changed minimally with spin. Above an angle of attack of 15°, the overturning moment would be destabilizing. At low angles of attack (less than 15°), the overturning moment would tend to decrease the target’s angle of attack, indicating the lack of a need for spin for stability at small angles. This stabilizing moment would cause the target to move in a mildly damped oscillation about the axis parallel to the free-stream velocity vector through the target’s center of gravity.

  13. A Novel Attitude Determination System Aided by Polarization Sensor

    Directory of Open Access Journals (Sweden)

    Wei Zhi

    2018-01-01

    Full Text Available This paper aims to develop a novel attitude determination system aided by polarization sensor. An improved heading angle function is derived using the perpendicular relationship between directions of E-vector of linearly polarized light and solar vector in the atmospheric polarization distribution model. The Extended Kalman filter (EKF with quaternion differential equation as a dynamic model is applied to fuse the data from sensors. The covariance functions of filter process and measurement noises are deduced in detail. The indoor and outdoor tests are conducted to verify the validity and feasibility of proposed attitude determination system. The test results showed that polarization sensor is not affected by magnetic field, thus the proposed system can work properly in environments containing the magnetic interference. The results also showed that proposed system has higher measurement accuracy than common attitude determination system and can provide precise parameters for Unmanned Aerial Vehicle (UAV flight control. The main contribution of this paper is implementation of the EKF for incorporating the self-developed polarization sensor into the conventional attitude determination system. The real-world experiment with the quad-rotor proved that proposed system can work in a magnetic interference environment and provide sufficient accuracy in attitude determination for autonomous navigation of vehicle.

  14. A Novel Attitude Determination System Aided by Polarization Sensor.

    Science.gov (United States)

    Zhi, Wei; Chu, Jinkui; Li, Jinshan; Wang, Yinlong

    2018-01-09

    This paper aims to develop a novel attitude determination system aided by polarization sensor. An improved heading angle function is derived using the perpendicular relationship between directions of E-vector of linearly polarized light and solar vector in the atmospheric polarization distribution model. The Extended Kalman filter (EKF) with quaternion differential equation as a dynamic model is applied to fuse the data from sensors. The covariance functions of filter process and measurement noises are deduced in detail. The indoor and outdoor tests are conducted to verify the validity and feasibility of proposed attitude determination system. The test results showed that polarization sensor is not affected by magnetic field, thus the proposed system can work properly in environments containing the magnetic interference. The results also showed that proposed system has higher measurement accuracy than common attitude determination system and can provide precise parameters for Unmanned Aerial Vehicle (UAV) flight control. The main contribution of this paper is implementation of the EKF for incorporating the self-developed polarization sensor into the conventional attitude determination system. The real-world experiment with the quad-rotor proved that proposed system can work in a magnetic interference environment and provide sufficient accuracy in attitude determination for autonomous navigation of vehicle.

  15. Effects of sample injection amount and time-of-flight mass spectrometric detection dynamic range on metabolome analysis by high-performance chemical isotope labeling LC-MS.

    Science.gov (United States)

    Zhou, Ruokun; Li, Liang

    2015-04-06

    The effect of sample injection amount on metabolome analysis in a chemical isotope labeling (CIL) liquid chromatography-mass spectrometry (LC-MS) platform was investigated. The performance of time-of-flight (TOF) mass spectrometers with and without a high-dynamic-range (HD) detection system was compared in the analysis of (12)C2/(13)C2-dansyl labeled human urine samples. An average of 1635 ± 21 (n = 3) peak pairs or putative metabolites was detected using the HD-TOF-MS, compared to 1429 ± 37 peak pairs from a conventional or non-HD TOF-MS. In both instruments, signal saturation was observed. However, in the HD-TOF-MS, signal saturation was mainly caused by the ionization process, while in the non-HD TOF-MS, it was caused by the detection process. To extend the MS detection range in the non-HD TOF-MS, an automated switching from using (12)C to (13)C-natural abundance peaks for peak ratio calculation when the (12)C peaks are saturated has been implemented in IsoMS, a software tool for processing CIL LC-MS data. This work illustrates that injecting an optimal sample amount is important to maximize the metabolome coverage while avoiding the sample carryover problem often associated with over-injection. A TOF mass spectrometer with an enhanced detection dynamic range can also significantly increase the number of peak pairs detected. In chemical isotope labeling (CIL) LC-MS, relative metabolite quantification is done by measuring the peak ratio of a (13)C2-/(12)C2-labeled peak pair for a given metabolite present in two comparative samples. The dynamic range of peak ratio measurement does not need to be very large, as only subtle changes of metabolite concentrations are encountered in most metabolomic studies where relative metabolome quantification of different groups of samples is performed. However, the absolute concentrations of different metabolites can be very different, requiring a technique to provide a wide detection dynamic range to allow the detection of as

  16. Free Flight Ground Testing of ADEPT in Advance of the Sounding Rocket One Flight Experiment

    Science.gov (United States)

    Smith, B. P.; Dutta, S.

    2017-01-01

    The Adaptable Deployable Entry and Placement Technology (ADEPT) project will be conducting the first flight test of ADEPT, titled Sounding Rocket One (SR-1), in just two months. The need for this flight test stems from the fact that ADEPT's supersonic dynamic stability has not yet been characterized. The SR-1 flight test will provide critical data describing the flight mechanics of ADEPT in ballistic flight. These data will feed decision making on future ADEPT mission designs. This presentation will describe the SR-1 scientific data products, possible flight test outcomes, and the implications of those outcomes on future ADEPT development. In addition, this presentation will describe free-flight ground testing performed in advance of the flight test. A subsonic flight dynamics test conducted at the Vertical Spin Tunnel located at NASA Langley Research Center provided subsonic flight dynamics data at high and low altitudes for multiple center of mass (CoM) locations. A ballistic range test at the Hypervelocity Free Flight Aerodynamics Facility (HFFAF) located at NASA Ames Research Center provided supersonic flight dynamics data at low supersonic Mach numbers. Execution and outcomes of these tests will be discussed. Finally, a hypothesized trajectory estimate for the SR-1 flight will be presented.

  17. The Dynamics of Language Learning Attitudes and Motivation: Lessons from an Interview Study of Dyslexic Language Learners

    Science.gov (United States)

    Csizer, Kata; Kormos, Judit; Sarkadi, Agnes

    2010-01-01

    The aim of our study was to provide an insider's account of the dynamics of language learning motivation in Hungarian students with dyslexia. For this purpose, we conducted qualitative interviews with 15 students who studied foreign languages in a variety of educational settings. In this article, we drew up a dynamic model of language learning…

  18. A model of scientific attitudes assessment by observation in physics learning based scientific approach: case study of dynamic fluid topic in high school

    Science.gov (United States)

    Yusliana Ekawati, Elvin

    2017-01-01

    This study aimed to produce a model of scientific attitude assessment in terms of the observations for physics learning based scientific approach (case study of dynamic fluid topic in high school). Development of instruments in this study adaptation of the Plomp model, the procedure includes the initial investigation, design, construction, testing, evaluation and revision. The test is done in Surakarta, so that the data obtained are analyzed using Aiken formula to determine the validity of the content of the instrument, Cronbach’s alpha to determine the reliability of the instrument, and construct validity using confirmatory factor analysis with LISREL 8.50 program. The results of this research were conceptual models, instruments and guidelines on scientific attitudes assessment by observation. The construct assessment instruments include components of curiosity, objectivity, suspended judgment, open-mindedness, honesty and perseverance. The construct validity of instruments has been qualified (rated load factor > 0.3). The reliability of the model is quite good with the Alpha value 0.899 (> 0.7). The test showed that the model fits the theoretical models are supported by empirical data, namely p-value 0.315 (≥ 0.05), RMSEA 0.027 (≤ 0.08)

  19. Nonlinear Robust Control of a Hypersonic Flight Vehicle Using Fuzzy Disturbance Observer

    Directory of Open Access Journals (Sweden)

    Lei Zhengdong

    2013-01-01

    Full Text Available This paper is concerned with a novel tracking controller design for a hypersonic flight vehicle in complex and volatile environment. The attitude control model is challengingly constructed with multivariate uncertainties and external disturbances, such as structure dynamic and stochastic wind disturbance. In order to resist the influence of uncertainties and disturbances on the flight control system, nonlinear disturbance observer is introduced to estimate them. Moreover, for the sake of high accuracy and sensitivity, fuzzy theory is adopted to improve the performance of the nonlinear disturbance observer. After the total disturbance is eliminated by dynamic inversion method, a cascade system is obtained and then stabilized by a sliding-mode controller. Finally, simulation results show that the strong robust controller achieves excellent performance when the closed-loop control system is influenced by mass uncertainties and external disturbances.

  20. ATTITUDE DETERMINATION AND CONTROL SYSTEM OF KITSAT-1

    Directory of Open Access Journals (Sweden)

    Hyunwoo Lee

    1996-06-01

    Full Text Available The attitude dynamics of KITSAT-1 are modeled including the gravity gradient stabilization method. We define the operation scenario during the initial attitude stabilization period by means of a magnetorquering control algorithm. The required constraints for the gravity gradient boom deployment are also examined. Attitude dynamics model and control laws are verified by analyzing in-orbit attitude sensor telemetry data.

  1. Flight Test of an Intelligent Flight-Control System

    Science.gov (United States)

    Davidson, Ron; Bosworth, John T.; Jacobson, Steven R.; Thomson, Michael Pl; Jorgensen, Charles C.

    2003-01-01

    The F-15 Advanced Controls Technology for Integrated Vehicles (ACTIVE) airplane (see figure) was the test bed for a flight test of an intelligent flight control system (IFCS). This IFCS utilizes a neural network to determine critical stability and control derivatives for a control law, the real-time gains of which are computed by an algorithm that solves the Riccati equation. These derivatives are also used to identify the parameters of a dynamic model of the airplane. The model is used in a model-following portion of the control law, in order to provide specific vehicle handling characteristics. The flight test of the IFCS marks the initiation of the Intelligent Flight Control System Advanced Concept Program (IFCS ACP), which is a collaboration between NASA and Boeing Phantom Works. The goals of the IFCS ACP are to (1) develop the concept of a flight-control system that uses neural-network technology to identify aircraft characteristics to provide optimal aircraft performance, (2) develop a self-training neural network to update estimates of aircraft properties in flight, and (3) demonstrate the aforementioned concepts on the F-15 ACTIVE airplane in flight. The activities of the initial IFCS ACP were divided into three Phases, each devoted to the attainment of a different objective. The objective of Phase I was to develop a pre-trained neural network to store and recall the wind-tunnel-based stability and control derivatives of the vehicle. The objective of Phase II was to develop a neural network that can learn how to adjust the stability and control derivatives to account for failures or modeling deficiencies. The objective of Phase III was to develop a flight control system that uses the neural network outputs as a basis for controlling the aircraft. The flight test of the IFCS was performed in stages. In the first stage, the Phase I version of the pre-trained neural network was flown in a passive mode. The neural network software was running using flight data

  2. Vision based flight procedure stereo display system

    Science.gov (United States)

    Shen, Xiaoyun; Wan, Di; Ma, Lan; He, Yuncheng

    2008-03-01

    A virtual reality flight procedure vision system is introduced in this paper. The digital flight map database is established based on the Geographic Information System (GIS) and high definitions satellite remote sensing photos. The flight approaching area database is established through computer 3D modeling system and GIS. The area texture is generated from the remote sensing photos and aerial photographs in various level of detail. According to the flight approaching procedure, the flight navigation information is linked to the database. The flight approaching area vision can be dynamic displayed according to the designed flight procedure. The flight approaching area images are rendered in 2 channels, one for left eye images and the others for right eye images. Through the polarized stereoscopic projection system, the pilots and aircrew can get the vivid 3D vision of the flight destination approaching area. Take the use of this system in pilots preflight preparation procedure, the aircrew can get more vivid information along the flight destination approaching area. This system can improve the aviator's self-confidence before he carries out the flight mission, accordingly, the flight safety is improved. This system is also useful in validate the visual flight procedure design, and it helps to the flight procedure design.

  3. Image-Based Computational Fluid Dynamics in Blood Vessel Models: Toward Developing a Prognostic Tool to Assess Cardiovascular Function Changes in Prolonged Space Flights

    Science.gov (United States)

    Chatzimavroudis, George P.; Spirka, Thomas A.; Setser, Randolph M.; Myers, Jerry G.

    2004-01-01

    One of NASA's objectives is to be able to perform a complete, pre-flight, evaluation of cardiovascular changes in astronauts scheduled for prolonged space missions. Computational fluid dynamics (CFD) has shown promise as a method for estimating cardiovascular function during reduced gravity conditions. For this purpose, MRI can provide geometrical information, to reconstruct vessel geometries, and measure all spatial velocity components, providing location specific boundary conditions. The objective of this study was to investigate the reliability of MRI-based model reconstruction and measured boundary conditions for CFD simulations. An aortic arch model and a carotid bifurcation model were scanned in a 1.5T Siemens MRI scanner. Axial MRI acquisitions provided images for geometry reconstruction (slice thickness 3 and 5 mm; pixel size 1x1 and 0.5x0.5 square millimeters). Velocity acquisitions provided measured inlet boundary conditions and localized three-directional steady-flow velocity data (0.7-3.0 L/min). The vessel walls were isolated using NIH provided software (ImageJ) and lofted to form the geometric surface. Constructed and idealized geometries were imported into a commercial CFD code for meshing and simulation. Contour and vector plots of the velocity showed identical features between the MRI velocity data, the MRI-based CFD data, and the idealized-geometry CFD data, with less than 10% differences in the local velocity values. CFD results on models reconstructed from different MRI resolution settings showed insignificant differences (less than 5%). This study illustrated, quantitatively, that reliable CFD simulations can be performed with MRI reconstructed models and gives evidence that a future, subject-specific, computational evaluation of the cardiovascular system alteration during space travel is feasible.

  4. Attitude Strength.

    Science.gov (United States)

    Howe, Lauren C; Krosnick, Jon A

    2017-01-03

    Attitude strength has been the focus of a huge volume of research in psychology and related sciences for decades. The insights offered by this literature have tremendous value for understanding attitude functioning and structure and for the effective application of the attitude concept in applied settings. This is the first Annual Review of Psychology article on the topic, and it offers a review of theory and evidence regarding one of the most researched strength-related attitude features: attitude importance. Personal importance is attached to an attitude when the attitude is perceived to be relevant to self-interest, social identification with reference groups or reference individuals, and values. Attaching personal importance to an attitude causes crystallizing of attitudes (via enhanced resistance to change), effortful gathering and processing of relevant information, accumulation of a large store of well-organized relevant information in long-term memory, enhanced attitude extremity and accessibility, enhanced attitude impact on the regulation of interpersonal attraction, energizing of emotional reactions, and enhanced impact of attitudes on behavioral intentions and action. Thus, important attitudes are real and consequential psychological forces, and their study offers opportunities for addressing behavioral change.

  5. Flapping Wing Flight Dynamic Modeling

    Science.gov (United States)

    2011-08-22

    is a subset of the matrix calculated for trim calculations based on periodic shooting. For stability we have φ = eAT where the eigenvalues of A...Stream, Tech. Rep. 1326, NACA, June 1947. [22] Wagner, H., Uber die Entstehung des Dynamischen Auftriebs von Tragugeln, Bd. 5, ZAMM, Feb 1925. [23

  6. Obliteration dynamics in cerebral arteriovenous malformations after cyberknife radiosurgery: quantification with sequential nidus volumetry and 3-tesla 3-dimensional time-of-flight magnetic resonance angiography.

    Science.gov (United States)

    Wowra, Berndt; Muacevic, Alexander; Tonn, Jörg-Christian; Schoenberg, Stefan O; Reiser, Maximilian; Herrmann, Karin A

    2009-02-01

    To investigate the time-dependent obliteration of cerebral arteriovenous malformations (cAVM) after CyberKnife radiosurgery (CKRS) (Accuray, Inc., Sunnyvale, CA) by means of sequential 3-T, 3-dimensional (3D), time-of-flight (TOF) magnetic resonance angiography (MRA), and volumetry of the arteriovenous malformation (AVM) nidus. In this prospective study, 3D TOF MRA was performed on 20 patients with cAVMs treated by single-fraction CKRS. Three-dimensional TOF MRA was performed on a 3-T, 32-channel magnetic resonance scanner (Magnetom TIM Trio; Siemens Medical Solutions, Erlangen, Germany) with isotropic voxel size at a spatial resolution of 0.6 x 0.6 x 0.6 mm3. The time-dependent relative decay of the transnidal blood flow evidenced by 3D TOF MRA was referred to as "obliteration dynamics." Volumetry of the nidus size was performed with OsiriX imaging software (OsiriX Foundation, Geneva, Switzerland). All patients had 3 to 4 follow-up examinations at 3- to 6-month intervals over a minimum follow-up period of 9 months. Subtotal obliteration was determined if the residual nidus volume was 5% or less of the initial nidus volume. Stata/IC software (Version 10.0; Stata Corp., College Station, TX) was used for statistical analysis and to identify potential factors of AVM obliteration. Regarding their clinical status, case history, and pretreatments, the participants of this study represent difficult-to-treat cAVM patients. The median nidus volume was 1.8 mL (range, 0.4-12.5 mL); the median minimum dose prescribed to the nidus was 22 Gy (range, 16-24 Gy) delivered to the 67% isodose line (range, 55-80%). CKRS was well tolerated, with complications in 2 patients. No further hemorrhages occurred after RS, except 1 small and clinically inapparent incident. The median follow-up period after RS was 25.0 months (range, 11.7-36.8 months). After RS, a statistically significant obliteration was observed in all patients. However, the obliteration dynamics of the cAVMs showed a

  7. Filtering Methods for Error Reduction in Spacecraft Attitude Estimation Using Quaternion Star Trackers

    Science.gov (United States)

    Calhoun, Philip C.; Sedlak, Joseph E.; Superfin, Emil

    2011-01-01

    Precision attitude determination for recent and planned space missions typically includes quaternion star trackers (ST) and a three-axis inertial reference unit (IRU). Sensor selection is based on estimates of knowledge accuracy attainable from a Kalman filter (KF), which provides the optimal solution for the case of linear dynamics with measurement and process errors characterized by random Gaussian noise with white spectrum. Non-Gaussian systematic errors in quaternion STs are often quite large and have an unpredictable time-varying nature, particularly when used in non-inertial pointing applications. Two filtering methods are proposed to reduce the attitude estimation error resulting from ST systematic errors, 1) extended Kalman filter (EKF) augmented with Markov states, 2) Unscented Kalman filter (UKF) with a periodic measurement model. Realistic assessments of the attitude estimation performance gains are demonstrated with both simulation and flight telemetry data from the Lunar Reconnaissance Orbiter.

  8. Attitude of Student Teachers towards Teaching Profession

    Science.gov (United States)

    Bhargava, Anupama; Pathy, M. K.

    2014-01-01

    Teaching being a dynamic activity requires a favourable attitude and certain specific competencies from its practitioners. Teachers' proficiency depends on the attitude she possesses for the profession. The positive attitude helps teacher to develop a conductive learner friendly environment in the classroom. This also casts a fruitful effect on…

  9. Contrast variation by dynamic nuclear polarization and time-of-flight small-angle neutron scattering. I. Application to industrial multi-component nanocomposites1

    Science.gov (United States)

    Noda, Yohei; Koizumi, Satoshi; Masui, Tomomi; Mashita, Ryo; Kishimoto, Hiroyuki; Yamaguchi, Daisuke; Kumada, Takayuki; Takata, Shin-ichi; Ohishi, Kazuki; Suzuki, Jun-ichi

    2016-01-01

    Dynamic nuclear polarization (DNP) at low temperature (1.2 K) and high magnetic field (3.3 T) was applied to a contrast variation study in small-angle neutron scattering (SANS) focusing on industrial rubber materials. By varying the scattering contrast by DNP, time-of-flight SANS profiles were obtained at the pulsed neutron source of the Japan Proton Accelerator Research Complex (J-PARC). The concentration of a small organic molecule, (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO), was carefully controlled by a doping method using vapour sorption into the rubber specimens. With the assistance of microwave irradiation (94 GHz), almost full polarization of the paramagnetic electronic spin of TEMPO was transferred to the spin state of hydrogen (protons) in the rubber materials to obtain a high proton spin polarization (P H). The following samples were prepared: (i) a binary mixture of styrene–butadiene random copolymer (SBR) with silica particles (SBR/SP); and (ii) a ternary mixture of SBR with silica and carbon black particles (SBR/SP/CP). For the binary mixture (SBR/SP), the intensity of SANS significantly increased or decreased while keeping its q dependence for P H = −35% or P H = 40%, respectively. The q behaviour of SANS for the SBR/SP mixture can be reproduced using the form factor of a spherical particle. The intensity at low q (∼0.01 Å−1) varied as a quadratic function of P H and indicated a minimum value at P H = 30%, which can be explained by the scattering contrast between SP and SBR. The scattering intensity at high q (∼0.3 Å−1) decreased with increasing P H, which is attributed to the incoherent scattering from hydrogen. For the ternary mixture (SBR/SP/CP), the q behaviour of SANS was varied by changing P H. At P H = −35%, the scattering maxima originating from the form factor of SP prevailed, whereas at P H = 29% and P H = 38%, the scattering maxima disappeared. After decomposition of the total SANS according to inverse matrix

  10. Annual view (1999) - aeronautic relation/space relation. Aeronautic relation - flight dynamics; Nenkan tenbo (1999) koku kankei uchu kankei. Hiko rikigaku kanren

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-05

    The problem peculiar to FY 1999 is the Y2K problem. Aircraft makers, The Boeing Co. and Air Bus Co. had conducted surveys of influences of all the parts including micro chips from a standpoint of their guaranteeing airworthiness, and had confirmed that there won't occur troubles. And each airline company also conducted ground tests using real airplanes and confirmed that there are no problems. Further, big three airlines made test flights by having real planes seen the old year out by adjusting the date and reconfirmed safety. As to the technical research on the defense relation, cited are 'a study of the future control system' and 'a study of airliner flight management/control system.' To enhance safety of aircraft, Kawasaki Heavy Industries and Furuno Electric Co. are developing the aircraft relative position monitoring system. In another study on safety, a study of RFCS (restructurable/reconfigurable flight control system) is being proceeded with. In RFCS, if airplane has a trouble, the control system is automatically revised for maintaining flight safety and flight performance. (NEDO)

  11. Numerical simulation of hypersonic flight experiment vehicle

    OpenAIRE

    Yamamoto, Yukimitsu; Yoshioka, Minako; 山本 行光; 吉岡 美菜子

    1994-01-01

    Hypersonic aerodynamic characteristics of Hypersonic FLight EXperiment (HYFLEX vehicle were investigated by numerical simulations using Navier-Stokes CFD (Computational Fluid Dynamics) code of NAL. Numerical results were compared with experimental data obtained at Hypersonic Wind Tunnel at NAL. In order to investigate real flight aerodynamic characteristics. numerical calculations corresponding to the flight conditions suffering from maximum aero thermodynamic heating were also made and the d...

  12. Flight Test Maneuvers for Efficient Aerodynamic Modeling

    Science.gov (United States)

    Morelli, Eugene A.

    2011-01-01

    Novel flight test maneuvers for efficient aerodynamic modeling were developed and demonstrated in flight. Orthogonal optimized multi-sine inputs were applied to aircraft control surfaces to excite aircraft dynamic response in all six degrees of freedom simultaneously while keeping the aircraft close to chosen reference flight conditions. Each maneuver was designed for a specific modeling task that cannot be adequately or efficiently accomplished using conventional flight test maneuvers. All of the new maneuvers were first described and explained, then demonstrated on a subscale jet transport aircraft in flight. Real-time and post-flight modeling results obtained using equation-error parameter estimation in the frequency domain were used to show the effectiveness and efficiency of the new maneuvers, as well as the quality of the aerodynamic models that can be identified from the resultant flight data.

  13. Daedalus - Last Dryden flight

    Science.gov (United States)

    1988-01-01

    The Daedalus 88, with Glenn Tremml piloting, is seen here on its last flight for the NASA Dryden Flight Research Center, Edwards, California. The Light Eagle and Daedalus human powered aircraft were testbeds for flight research conducted at Dryden between January 1987 and March 1988. These unique aircraft were designed and constructed by a group of students, professors, and alumni of the Massachusetts Institute of Technology within the context of the Daedalus project. The construction of the Light Eagle and Daedalus aircraft was funded primarily by the Anheuser Busch and United Technologies Corporations, respectively, with additional support from the Smithsonian Air and Space Museum, MIT, and a number of other sponsors. To celebrate the Greek myth of Daedalus, the man who constructed wings of wax and feathers to escape King Minos, the Daedalus project began with the goal of designing, building and testing a human-powered aircraft that could fly the mythical distance, 115 km. To achieve this goal, three aircraft were constructed. The Light Eagle was the prototype aircraft, weighing 92 pounds. On January 22, 1987, it set a closed course distance record of 59 km, which still stands. Also in January of 1987, the Light Eagle was powered by Lois McCallin to set the straight distance, the distance around a closed circuit, and the duration world records for the female division in human powered vehicles. Following this success, two more aircraft were built, the Daedalus 87 and Daedalus 88. Each aircraft weighed approximately 69 pounds. The Daedalus 88 aircraft was the ship that flew the 199 km from the Iraklion Air Force Base on Crete in the Mediterranean Sea, to the island of Santorini in 3 hours, 54 minutes. In the process, the aircraft set new records in distance and endurance for a human powered aircraft. The specific areas of flight research conducted at Dryden included characterizing the rigid body and flexible dynamics of the Light Eagle, investigating sensors for an

  14. Integrated guidance and control design of a flight vehicle with side-window detection

    Directory of Open Access Journals (Sweden)

    Tianyu ZHENG

    2018-04-01

    Full Text Available This paper considers the guidance and control problem of a flight vehicle with side-window detection. In order to guarantee the target remaining in the seeker's sight of view, the line of sight and the attitude of the flight vehicle should be under some constraints caused by the side-window, which leads to coupling between the guidance and the attitude dynamics model. To deal with the side-window constraints and the coupling, a novel Integrated Guidance and Control (IGC design approach is proposed. Firstly, the relative motion equations are derived in the body-Line of Sight (LOS coordinate system. And the guidance and control problem of the flight vehicle is formulated into an IGC problem with state constraints. Then, based on the singular perturbation method, the IGC problem is decomposed into the control design of the quasi-steady-state subsystem and the boundary-layer subsystem which can be designed separately. Finally, the receding horizon control is applied to the control design for the two subsystems. Simulation results show the effectiveness of the proposed approach. Keywords: Integrated guidance and control, Receding horizon control, Side-window detection, Singular perturbation, Terminal guidance

  15. Adaptive Augmenting Control Flight Characterization Experiment on an F/A-18

    Science.gov (United States)

    VanZwieten, Tannen S.; Orr, Jeb S.; Wall, John H.; Gilligan, Eric T.

    2014-01-01

    This paper summarizes the Adaptive Augmenting Control (AAC) flight characterization experiments performed using an F/A-18 (TN 853). AAC was designed and developed specifically for launch vehicles, and is currently part of the baseline autopilot design for NASA's Space Launch System (SLS). The scope covered here includes a brief overview of the algorithm (covered in more detail elsewhere), motivation and benefits of flight testing, top-level SLS flight test objectives, applicability of the F/A-18 as a platform for testing a launch vehicle control design, test cases designed to fully vet the AAC algorithm, flight test results, and conclusions regarding the functionality of AAC. The AAC algorithm developed at Marshall Space Flight Center is a forward loop gain multiplicative adaptive algorithm that modifies the total attitude control system gain in response to sensed model errors or undesirable parasitic mode resonances. The AAC algorithm provides the capability to improve or decrease performance by balancing attitude tracking with the mitigation of parasitic dynamics, such as control-structure interaction or servo-actuator limit cycles. In the case of the latter, if unmodeled or mismodeled parasitic dynamics are present that would otherwise result in a closed-loop instability or near instability, the adaptive controller decreases the total loop gain to reduce the interaction between these dynamics and the controller. This is in contrast to traditional adaptive control logic, which focuses on improving performance by increasing gain. The computationally simple AAC attitude control algorithm has stability properties that are reconcilable in the context of classical frequency-domain criteria (i.e., gain and phase margin). The algorithm assumes that the baseline attitude control design is well-tuned for a nominal trajectory and is designed to adapt only when necessary. Furthermore, the adaptation is attracted to the nominal design and adapts only on an as-needed basis

  16. Impact of time-of-flight on indirect 3D and direct 4D parametric image reconstruction in the presence of inconsistent dynamic PET data

    NARCIS (Netherlands)

    Kotasidis, F. A.; Mehranian, A.; Zaidi, H.

    2016-01-01

    Kinetic parameter estimation in dynamic PET suffers from reduced accuracy and precision when parametric maps are estimated using kinetic modelling following image reconstruction of the dynamic data. Direct approaches to parameter estimation attempt to directly estimate the kinetic parameters from

  17. Orion Exploration Flight Test-1 Post-Flight Navigation Performance Assessment Relative to the Best Estimated Trajectory

    Science.gov (United States)

    Gay, Robert S.; Holt, Greg N.; Zanetti, Renato

    2016-01-01

    This paper details the post-flight navigation performance assessment of the Orion Exploration Flight Test-1 (EFT-1). Results of each flight phase are presented: Ground Align, Ascent, Orbit, and Entry Descent and Landing. This study examines the on-board Kalman Filter uncertainty along with state deviations relative to the Best Estimated Trajectory (BET). Overall the results show that the Orion Navigation System performed as well or better than expected. Specifically, the Global Positioning System (GPS) measurement availability was significantly better than anticipated at high altitudes. In addition, attitude estimation via processing GPS measurements along with Inertial Measurement Unit (IMU) data performed very well and maintained good attitude throughout the mission.

  18. Icarus and Jonah: Flight and Containment in Cendrars's Work

    Directory of Open Access Journals (Sweden)

    Nicole Dupré

    1979-01-01

    Full Text Available The study of two dreams and other related texts will show the ambivalent dynamism of Cendrars's imaginary universe. The first dream is a claustrophobic nightmare. The evident symbolism of the images reveals Cendrars's visceral need for changes and evasion as well as his constant rejection of limits. Both life and work follow the dynamics of escape and promote an ideology of separation. The second dream is a dream of flight. Its symbolism and the numerous thematic variations encountered stress the dynamics of ascension and outline an ideology of the quest, complementary to the first dream. This attitude is defined as an Icarus complex, the metaphysical dimension of which explains Cendrars's disappointment with action and adventure. A third group of figures suggests a new direction for Cendrars's aspirations, now related to the dynamics of fall. A strong desire for isolation and reclusion bears witness to a Jonah complex. Torn by contradictory longings, Cendrars's split personality cannot experience unity except in a very transitory and frail stage such as the ambulatory cell or the dark room of imagination. Only writing, Cendrars's voluntary prison as well as spiritual adventure, allows the author to transcend the original dilemma.

  19. Linearizing feedforward/feedback attitude control

    Science.gov (United States)

    Paielli, Russell A.; Bach, Ralph E.

    1991-01-01

    An approach to attitude control theory is introduced in which a linear form is postulated for the closed-loop rotation error dynamics, then the exact control law required to realize it is derived. The nonminimal (four-component) quaternion form is used to attitude because it is globally nonsingular, but the minimal (three-component) quaternion form is used for attitude error because it has no nonlinear constraints to prevent the rotational error dynamics from being linearized, and the definition of the attitude error is based on quaternion algebra. This approach produces an attitude control law that linearizes the closed-loop rotational error dynamics exactly, without any attitude singularities, even if the control errors become large.

  20. Statistical Attitude Determination

    Science.gov (United States)

    Markley, F. Landis

    2010-01-01

    All spacecraft require attitude determination at some level of accuracy. This can be a very coarse requirement of tens of degrees, in order to point solar arrays at the sun, or a very fine requirement in the milliarcsecond range, as required by Hubble Space Telescope. A toolbox of attitude determination methods, applicable across this wide range, has been developed over the years. There have been many advances in the thirty years since the publication of Reference, but the fundamentals remain the same. One significant change is that onboard attitude determination has largely superseded ground-based attitude determination, due to the greatly increased power of onboard computers. The availability of relatively inexpensive radiation-hardened microprocessors has led to the development of "smart" sensors, with autonomous star trackers being the first spacecraft application. Another new development is attitude determination using interferometry of radio signals from the Global Positioning System (GPS) constellation. This article reviews both the classic material and these newer developments at approximately the level of, with emphasis on. methods suitable for use onboard a spacecraft. We discuss both "single frame" methods that are based on measurements taken at a single point in time, and sequential methods that use information about spacecraft dynamics to combine the information from a time series of measurements.

  1. Selected Flight Test Results for Online Learning Neural Network-Based Flight Control System

    Science.gov (United States)

    Williams-Hayes, Peggy S.

    2004-01-01

    The NASA F-15 Intelligent Flight Control System project team developed a series of flight control concepts designed to demonstrate neural network-based adaptive controller benefits, with the objective to develop and flight-test control systems using neural network technology to optimize aircraft performance under nominal conditions and stabilize the aircraft under failure conditions. This report presents flight-test results for an adaptive controller using stability and control derivative values from an online learning neural network. A dynamic cell structure neural network is used in conjunction with a real-time parameter identification algorithm to estimate aerodynamic stability and control derivative increments to baseline aerodynamic derivatives in flight. This open-loop flight test set was performed in preparation for a future phase in which the learning neural network and parameter identification algorithm output would provide the flight controller with aerodynamic stability and control derivative updates in near real time. Two flight maneuvers are analyzed - pitch frequency sweep and automated flight-test maneuver designed to optimally excite the parameter identification algorithm in all axes. Frequency responses generated from flight data are compared to those obtained from nonlinear simulation runs. Flight data examination shows that addition of flight-identified aerodynamic derivative increments into the simulation improved aircraft pitch handling qualities.

  2. Ambiguity attitudes

    NARCIS (Netherlands)

    Trautmann, Stefan; van de Kuilen, Gijs; Keren, Gideon; Wu, George

    2015-01-01

    This chapter reviews the experimental literature on ambiguity attitudes, focusing on three topics. First, it considers various approaches to operationalize ambiguity in experiments. Second, the chapter reviews basic findings in the field regarding the prevalence of ambiguity aversion and ambiguity

  3. Studies of social group dynamics under isolated conditions. Objective summary of the literature as it relates to potential problems of long duration space flight

    Science.gov (United States)

    Vinograd, S. P.

    1974-01-01

    Scientific literature which deals with the study of human behavior and crew interaction in situations simulating long term space flight is summarized and organized. A bibliography of all the pertinent U.S. literature available is included, along with definitions of the behavioral characteristics terms employed. The summarized studies are analyzed according to behavioral factors and environmental conditions. The analysis consist of two matrices. (1) The matrix of factors studied correlates each research study area and individual study with the behavioral factors that were investigated in the study. (2) The matrix of conclusions identifies those studies whose investigators appeared to draw specific conclusions concerning questions of importance to NASA.

  4. Flight Test and Handling Qualities Analysis of a Longitudinal Flight Control System Using Multiobjective Techniques

    National Research Council Canada - National Science Library

    Anderson, John

    1998-01-01

    ...) and AFIT MXTOOLS toolboxes were used to produce the optimal, multiobjective designs. These designs were implemented for flight test on the Calspan VSS I Learjet, simulating the unstable longitudinal dynamics of an F-16 type aircraft...

  5. Estimating the Backup Reaction Wheel Orientation Using Reaction Wheel Spin Rates Flight Telemetry from a Spacecraft

    Science.gov (United States)

    Rizvi, Farheen

    2013-01-01

    A report describes a model that estimates the orientation of the backup reaction wheel using the reaction wheel spin rates telemetry from a spacecraft. Attitude control via the reaction wheel assembly (RWA) onboard a spacecraft uses three reaction wheels (one wheel per axis) and a backup to accommodate any wheel degradation throughout the course of the mission. The spacecraft dynamics prediction depends upon the correct knowledge of the reaction wheel orientations. Thus, it is vital to determine the actual orientation of the reaction wheels such that the correct spacecraft dynamics can be predicted. The conservation of angular momentum is used to estimate the orientation of the backup reaction wheel from the prime and backup reaction wheel spin rates data. The method is applied in estimating the orientation of the backup wheel onboard the Cassini spacecraft. The flight telemetry from the March 2011 prime and backup RWA swap activity on Cassini is used to obtain the best estimate for the backup reaction wheel orientation.

  6. Analytical investigation of the dynamics of tethered constellations in Earth orbit, phase 2

    Science.gov (United States)

    Lorenzini, Enrico C.; Gullahorn, Gordon E.; Cosmo, Mario L.; Estes, Robert D.; Grossi, Mario D.

    1994-01-01

    This final report covers nine years of research on future tether applications and on the actual flights of the Small Expendable Deployment System (SEDS). Topics covered include: (1) a description of numerical codes used to simulate the orbital and attitude dynamics of tethered systems during station keeping and deployment maneuvers; (2) a comparison of various tethered system simulators; (3) dynamics analysis, conceptual design, potential applications and propagation of disturbances and isolation from noise of a variable gravity/microgravity laboratory tethered to the Space Station; (4) stability of a tethered space centrifuge; (5) various proposed two-dimensional tethered structures for low Earth orbit for use as planar array antennas; (6) tethered high gain antennas; (7) numerical calculation of the electromagnetic wave field on the Earth's surface on an electrodynamically tethered satellite; (8) reentry of tethered capsules; (9) deployment dynamics of SEDS-1; (10) analysis of SEDS-1 flight data; and (11) dynamics and control of SEDS-2.

  7. Flight Dynamics and Abundance of Ips sexdentatus (Coleoptera: Curculionidae: Scolytinae in Different Sawmills from Northern Spain: Differences between Local Pinus radiata (Pinales: Pinaceae and Southern France Incoming P. pinaster Timber

    Directory of Open Access Journals (Sweden)

    Sergio López

    2012-01-01

    Full Text Available In January 2009, the windstorm “Klaus” struck the southern part of France, affecting 37.9 million m3 of maritime pine Pinus pinaster Aiton (Pinales: Pinaceae. This breeding plant material favored the outbreak of Ips sexdentatus (Börner (Coleoptera: Curculionidae: Scolytinae. As much of this timber is imported to the Basque Country (northern Spain, a potential risk to conifer stands is generated, due to the emergence of the incoming beetles. Thus, flight dynamics and beetle abundance were compared in different sawmills, according to the timber species (either local P. radiata D. Don or imported P. pinaster. A maximum flight peak of I. sexdentatus was observed in mid-June in P. pinaster importing sawmills, whereas a second lighter peak occurred in September. In contrast, only a maximum peak in mid-June was observed in P. radiata inhabiting beetles, being significantly smaller than in local P. pinaster trading sawmills. In addition, significant differences were found between imported P. pinaster and P. radiata regarding the number of insects beneath the bark. The development of IPM strategies for controlling I. sexdentatus populations is recommended, due to the insect abundance found in P. pinaster imported timber.

  8. Reusable Launch Vehicle Attitude Control Using a Time-Varying Sliding Mode Control Technique

    Science.gov (United States)

    Shtessel, Yuri B.; Zhu, J. Jim; Daniels, Dan; Jackson, Scott (Technical Monitor)

    2002-01-01

    In this paper we present a time-varying sliding mode control (TVSMC) technique for reusable launch vehicle (RLV) attitude control in ascent and entry flight phases. In ascent flight the guidance commands Euler roll, pitch and yaw angles, and in entry flight it commands the aerodynamic angles of bank, attack and sideslip. The controller employs a body rate inner loop and the attitude outer loop, which are separated in time-scale by the singular perturbation principle. The novelty of the TVSMC is that both the sliding surface and the boundary layer dynamics can be varied in real time using the PD-eigenvalue assignment technique. This salient feature is used to cope with control command saturation and integrator windup in the presence of severe disturbance or control effector failure, which enhances the robustness and fault tolerance of the controller. The TV-SMC ascent and descent designs are currently being tested with high fidelity, 6-DOF dispersion simulations. The test results will be presented in the final version of this paper.

  9. Venus radar mapper attitude reference quaternion

    Science.gov (United States)

    Lyons, D. T.

    1986-01-01

    Polynomial functions of time are used to specify the components of the quaternion which represents the nominal attitude of the Venus Radar mapper spacecraft during mapping. The following constraints must be satisfied in order to obtain acceptable synthetic array radar data: the nominal attitude function must have a large dynamic range, the sensor orientation must be known very accurately, the attitude reference function must use as little memory as possible, and the spacecraft must operate autonomously. Fitting polynomials to the components of the desired quaternion function is a straightforward method for providing a very dynamic nominal attitude using a minimum amount of on-board computer resources. Although the attitude from the polynomials may not be exactly the one requested by the radar designers, the polynomial coefficients are known, so they do not contribute to the attitude uncertainty. Frequent coefficient updates are not required, so the spacecraft can operate autonomously.

  10. Formal semantics for propositional attitudes

    Directory of Open Access Journals (Sweden)

    Daniel Vanderveken

    2011-06-01

    Full Text Available Contemporary logic is confined to a few paradigmatic attitudes such as belief, knowledge, desire and intention. My purpose is to present a general model-theoretical semantics of propositional attitudes of any cognitive or volitive mode. In my view, one can recursively define the set of all psychological modes of attitudes. As Descartes anticipated, the two primitive modes are those of belief and desire. Complex modes are obtained by adding to primitive modes special cognitive and volitive ways or special propositional content or preparatory conditions. According to standard logic of attitudes (Hintikka, human agents are either perfectly rational or totally irrational. I will proceed to a finer analysis of propositional attitudes that accounts for our imperfect but minimal rationality. For that purpose I will use a non standard predicative logic according to which propositions with the same truth conditions can have different cognitive values and I will explicate subjective in addition to objective possibilities. Next I will enumerate valid laws of my general logic of propositional attitudes. At the end I will state principles according to which minimally rational agents dynamically revise attitudes of any mode.

  11. The FLP microsatellite platform flight operations manual

    CERN Document Server

    2016-01-01

    This book represents the Flight Operations Manual for a reusable microsatellite platform – the “Future Low-cost Platform” (FLP), developed at the University of Stuttgart, Germany. It provides a basic insight on the onboard software functions, the core data handling system and on the power, communications, attitude control and thermal subsystem of the platform. Onboard failure detection, isolation and recovery functions are treated in detail. The platform is suited for satellites in the 50-150 kg class and is baseline of the microsatellite “Flying Laptop” from the University. The book covers the essential information for ground operators to controls an FLP-based satellite applying international command and control standards (CCSDS and ECSS PUS). Furthermore it provides an overview on the Flight Control Center in Stuttgart and on the link to the German Space Agency DLR Ground Station which is used for early mission phases. Flight procedure and mission planning chapters complement the book. .

  12. Control-oriented reduced order modeling of dipteran flapping flight

    Science.gov (United States)

    Faruque, Imraan

    Flying insects achieve flight stabilization and control in a manner that requires only small, specialized neural structures to perform the essential components of sensing and feedback, achieving unparalleled levels of robust aerobatic flight on limited computational resources. An engineering mechanism to replicate these control strategies could provide a dramatic increase in the mobility of small scale aerial robotics, but a formal investigation has not yet yielded tools that both quantitatively and intuitively explain flapping wing flight as an "input-output" relationship. This work uses experimental and simulated measurements of insect flight to create reduced order flight dynamics models. The framework presented here creates models that are relevant for the study of control properties. The work begins with automated measurement of insect wing motions in free flight, which are then used to calculate flight forces via an empirically-derived aerodynamics model. When paired with rigid body dynamics and experimentally measured state feedback, both the bare airframe and closed loop systems may be analyzed using frequency domain system identification. Flight dynamics models describing maneuvering about hover and cruise conditions are presented for example fruit flies (Drosophila melanogaster) and blowflies (Calliphorids). The results show that biologically measured feedback paths are appropriate for flight stabilization and sexual dimorphism is only a minor factor in flight dynamics. A method of ranking kinematic control inputs to maximize maneuverability is also presented, showing that the volume of reachable configurations in state space can be dramatically increased due to appropriate choice of kinematic inputs.

  13. Manned Flight Simulator (MFS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Aircraft Simulation Division, home to the Manned Flight Simulator (MFS), provides real-time, high fidelity, hardware-in-the-loop flight simulation capabilities...

  14. A model structure for identification of linear models of the UH-60 helicopter in hover and forward flight

    Science.gov (United States)

    1995-08-01

    A linear model structure applicable to identification of the UH-60 flight : dynamics in hover and forward flight without rotor-state data is developed. The : structure of the model is determined through consideration of the important : dynamic modes ...

  15. Development and Flight Testing of a Neural Network Based Flight Control System on the NF-15B Aircraft

    Science.gov (United States)

    Bomben, Craig R.; Smolka, James W.; Bosworth, John T.; Silliams-Hayes, Peggy S.; Burken, John J.; Larson, Richard R.; Buschbacher, Mark J.; Maliska, Heather A.

    2006-01-01

    The Intelligent Flight Control System (IFCS) project at the NASA Dryden Flight Research Center, Edwards AFB, CA, has been investigating the use of neural network based adaptive control on a unique NF-15B test aircraft. The IFCS neural network is a software processor that stores measured aircraft response information to dynamically alter flight control gains. In 2006, the neural network was engaged and allowed to learn in real time to dynamically alter the aircraft handling qualities characteristics in the presence of actual aerodynamic failure conditions injected into the aircraft through the flight control system. The use of neural network and similar adaptive technologies in the design of highly fault and damage tolerant flight control systems shows promise in making future aircraft far more survivable than current technology allows. This paper will present the results of the IFCS flight test program conducted at the NASA Dryden Flight Research Center in 2006, with emphasis on challenges encountered and lessons learned.

  16. Insect flight muscle metabolism

    NARCIS (Netherlands)

    Horst, D.J. van der; Beenakkers, A.M.Th.; Marrewijk, W.J.A. van

    1984-01-01

    The flight of an insect is of a very complicated and extremely energy-demanding nature. Wingbeat frequency may differ between various species but values up to 1000 Hz have been measured. Consequently metabolic activity may be very high during flight and the transition from rest to flight is

  17. In-Flight Self-Alignment Method Aided by Geomagnetism for Moving Basement of Guided Munitions

    Directory of Open Access Journals (Sweden)

    Shuang-biao Zhang

    2015-01-01

    Full Text Available Due to power-after-launch mode of guided munitions of high rolling speed, initial attitude of munitions cannot be determined accurately, and this makes it difficult for navigation and control system to work effectively and validly. An in-flight self-alignment method aided by geomagnetism that includes a fast in-flight coarse alignment method and an in-flight alignment model based on Kalman theory is proposed in this paper. Firstly a fast in-flight coarse alignment method is developed by using gyros, magnetic sensors, and trajectory angles. Then, an in-flight alignment model is derived by investigation of the measurement errors and attitude errors, which regards attitude errors as state variables and geomagnetic components in navigation frame as observed variables. Finally, fight data of a spinning projectile is used to verify the performance of the in-flight self-alignment method. The satisfying results show that (1 the precision of coarse alignment can attain below 5°; (2 the attitude errors by in-flight alignment model converge to 24′ at early of the latter half of the flight; (3 the in-flight alignment model based on Kalman theory has better adaptability, and show satisfying performance.

  18. Online Learning Flight Control for Intelligent Flight Control Systems (IFCS)

    Science.gov (United States)

    Niewoehner, Kevin R.; Carter, John (Technical Monitor)

    2001-01-01

    The research accomplishments for the cooperative agreement 'Online Learning Flight Control for Intelligent Flight Control Systems (IFCS)' include the following: (1) previous IFC program data collection and analysis; (2) IFC program support site (configured IFC systems support network, configured Tornado/VxWorks OS development system, made Configuration and Documentation Management Systems Internet accessible); (3) Airborne Research Test Systems (ARTS) II Hardware (developed hardware requirements specification, developing environmental testing requirements, hardware design, and hardware design development); (4) ARTS II software development laboratory unit (procurement of lab style hardware, configured lab style hardware, and designed interface module equivalent to ARTS II faceplate); (5) program support documentation (developed software development plan, configuration management plan, and software verification and validation plan); (6) LWR algorithm analysis (performed timing and profiling on algorithm); (7) pre-trained neural network analysis; (8) Dynamic Cell Structures (DCS) Neural Network Analysis (performing timing and profiling on algorithm); and (9) conducted technical interchange and quarterly meetings to define IFC research goals.

  19. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  20. Ares I-X Flight Test Philosophy

    Science.gov (United States)

    Davis, S. R.; Tuma, M. L.; Heitzman, K.

    2007-01-01

    In response to the Vision for Space Exploration, the National Aeronautics and Space Administration (NASA) has defined a new space exploration architecture to return humans to the Moon and prepare for human exploration of Mars. One of the first new developments will be the Ares I Crew Launch Vehicle (CLV), which will carry the Orion Crew Exploration Vehicle (CEV), into Low Earth Orbit (LEO) to support International Space Station (ISS) missions and, later, support lunar missions. As part of Ares I development, NASA will perform a series of Ares I flight tests. The tests will provide data that will inform the engineering and design process and verify the flight hardware and software. The data gained from the flight tests will be used to certify the new Ares/Orion vehicle for human space flight. The primary objectives of this first flight test (Ares I-X) are the following: Demonstrate control of a dynamically similar integrated Ares CLV/Orion CEV using Ares CLV ascent control algorithms; Perform an in-flight separation/staging event between an Ares I-similar First Stage and a representative Upper Stage; Demonstrate assembly and recovery of a new Ares CLV-like First Stage element at Kennedy Space Center (KSC); Demonstrate First Stage separation sequencing, and quantify First Stage atmospheric entry dynamics and parachute performance; and Characterize the magnitude of the integrated vehicle roll torque throughout the First Stage (powered) flight. This paper will provide an overview of the Ares I-X flight test process and details of the individual flight tests.

  1. CFD applications in hypersonic flight

    Science.gov (United States)

    Edwards, T. A.

    1992-01-01

    Design studies are underway for a variety of hypersonic flight vehicles. The National Aero-Space Plane will provide a reusable, single-stage-to-orbit capability for routine access to low earth orbit. Flight-capable satellites will dip into the atmosphere to maneuver to new orbits, while planetary probes will decelerate at their destination by atmospheric aerobraking. To supplement limited experimental capabilities in the hypersonic regime, CFD is being used to analyze the flow about these configurations. The governing equations include fluid dynamic as well as chemical species equations, which are solved with robust upwind differencing schemes. Examples of CFD applications to hypersonic vehicles suggest an important role this technology will play in the development of future aerospace systems. The computational resources needed to obtain solutions are large, but various strategies are being exploited to reduce the time required for complete vehicle simulations.

  2. Investigation of the spectroscopy and relaxation dynamics of benzaldehyde using molecular orbital calculations and laser ionization time-of-flight mass spectroscopy

    Science.gov (United States)

    da Silva, Maria Cristina Rodrigues

    1998-11-01

    Molecular orbital methods and laser ionization mass spectrometry measurements are used to investigate the spectroscopy and relaxation dynamics of benzaldehyde following excitation to its S2(/pi/pi/sp/*) state. Energies, equilibrium geometries and vibrational frequencies of ground and low-lying excited states of benzaldehyde neutral and cation determined by ab initio calculations provide a theoretical description of the electronic spectroscopy of benzaldehyde and of the changes occurring on excitation and ionization. The S2(/pi/pi/sp/*)[/gets]S0 excitation spectrum of jet-cooled benzaldehyde acquired using two-color laser ionization mass spectrometry techniques is interpreted with the aid of these calculations. The spectrum is dominated by the origin band and by transitions involving some of the ring modes consistent with the results of the molecular orbital calculations that indicate that the major geometric changes on excitation to S2 are located in the aromatic ring. Ten fundamental vibrations of the S2(/pi/pi/sp/*) state are assigned. The dissociation dynamics of benzaldehyde into benzene and carbon monoxide following excitation to its S2(/pi/pi/sp/*) state are investigated under jet- cooled conditions by two-color laser ionization mass spectrometry using a pump-probe technique. This experimental arrangement allows monitoring the benzaldehyde reactant and the benzene product ion signals as a function of the time delay between the excitation and ionization steps. A kinetic model is proposed to explain the observed biexponential decay of the benzaldehyde signal and the single exponential growth of the benzene product signal in terms of a sequential decay of two excited states of benzaldehyde, one of which leads to formation of benzene molecules in its lowest triplet state. Reactant disappearance and product appearance rates are determined for a number of vibronic transitions of the S2 state. They are found to increase with excitation energy without any indication

  3. Investigation of the electron dynamics of Si(111) 7 x 7 and development of a time-of-flight spectrometer for time- and angle-resolved two-photon photoemission

    International Nuclear Information System (INIS)

    Damm, Andreas

    2011-01-01

    This thesis consists of two main parts. The first one reports about recent investigations of the electron dynamics on the Si(111) 7 x 7 surface employing time- and angle-resolved two-photon photoemission (2PPE). The second part describes the construction and demonstration of the capabilities of a new electron time-of-flight spectrometer. It is shown that the electron dynamics of this surface are governed by adatom and bulk states. Variation of different experimental parameters leads to the suggestion that electrons scatter from the adatom states into the conduction band of Silicon. The localization in real space can be estimated from the distribution of the photoemission intensity in momentum space to be within one 7 x 7 unit cell. The electron population in the conduction band as well as those in the adatom band show a very long-living component. In addition to recombination through defect states, these electrons can undergo radiative recombination with holes in the valence band. The second part of this thesis reports about the design, construction and demonstration of the capabilities of a new electron time-of-flight spectrometer for applications in time- and angle-resolved 2PPE experiments. The new spectrometer is designed in a flexible manner to maximize either the energy resolution or the acceptance angle, respectively. By employing a position-sensitive electron detector it is possible for the first time to measure the energy as well as all components of the parallel momentum of the photoemitted electrons and thereby to fully characterize electrons from surface states. The time-resolution can be estimated from the width of a peak induced by photons scattered from the sample to be better than 150 ps. At the minimum of about 40 mm of the adjustable drift distance this leads to a energy resolution below 5 meV for electrons with kinetic energies of 1 eV. Thereby, the parallel momentum resolution is below 5 mA -1 for parallel momentum values k parallel ≤1A -1

  4. Cassini's Test Methodology for Flight Software Verification and Operations

    Science.gov (United States)

    Wang, Eric; Brown, Jay

    2007-01-01

    The Cassini spacecraft was launched on 15 October 1997 on a Titan IV-B launch vehicle. The spacecraft is comprised of various subsystems, including the Attitude and Articulation Control Subsystem (AACS). The AACS Flight Software (FSW) and its development has been an ongoing effort, from the design, development and finally operations. As planned, major modifications to certain FSW functions were designed, tested, verified and uploaded during the cruise phase of the mission. Each flight software upload involved extensive verification testing. A standardized FSW testing methodology was used to verify the integrity of the flight software. This paper summarizes the flight software testing methodology used for verifying FSW from pre-launch through the prime mission, with an emphasis on flight experience testing during the first 2.5 years of the prime mission (July 2004 through January 2007).

  5. Writing executable assertions to test flight software

    Science.gov (United States)

    Mahmood, A.; Andrews, D. M.; Mccluskey, E. J.

    1984-01-01

    An executable assertion is a logical statement about the variables or a block of code. If there is no error during execution, the assertion statement results in a true value. Executable assertions can be used for dynamic testing of software. They can be employed for validation during the design phase, and exception and error detection during the operation phase. The present investigation is concerned with the problem of writing executable assertions, taking into account the use of assertions for testing flight software. They can be employed for validation during the design phase, and for exception handling and error detection during the operation phase The digital flight control system and the flight control software are discussed. The considered system provides autopilot and flight director modes of operation for automatic and manual control of the aircraft during all phases of flight. Attention is given to techniques for writing and using assertions to test flight software, an experimental setup to test flight software, and language features to support efficient use of assertions.

  6. Flight control actuation system

    Science.gov (United States)

    Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

    2006-01-01

    A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

  7. Data Mining of NASA Boeing 737 Flight Data: Frequency Analysis of In-Flight Recorded Data

    Science.gov (United States)

    Butterfield, Ansel J.

    2001-01-01

    Data recorded during flights of the NASA Trailblazer Boeing 737 have been analyzed to ascertain the presence of aircraft structural responses from various excitations such as the engine, aerodynamic effects, wind gusts, and control system operations. The NASA Trailblazer Boeing 737 was chosen as a focus of the study because of a large quantity of its flight data records. The goal of this study was to determine if any aircraft structural characteristics could be identified from flight data collected for measuring non-structural phenomena. A number of such data were examined for spatial and frequency correlation as a means of discovering hidden knowledge of the dynamic behavior of the aircraft. Data recorded from on-board dynamic sensors over a range of flight conditions showed consistently appearing frequencies. Those frequencies were attributed to aircraft structural vibrations.

  8. Bat flight: aerodynamics, kinematics and flight morphology.

    Science.gov (United States)

    Hedenström, Anders; Johansson, L Christoffer

    2015-03-01

    Bats evolved the ability of powered flight more than 50 million years ago. The modern bat is an efficient flyer and recent research on bat flight has revealed many intriguing facts. By using particle image velocimetry to visualize wake vortices, both the magnitude and time-history of aerodynamic forces can be estimated. At most speeds the downstroke generates both lift and thrust, whereas the function of the upstroke changes with forward flight speed. At hovering and slow speed bats use a leading edge vortex to enhance the lift beyond that allowed by steady aerodynamics and an inverted wing during the upstroke to further aid weight support. The bat wing and its skeleton exhibit many features and control mechanisms that are presumed to improve flight performance. Whereas bats appear aerodynamically less efficient than birds when it comes to cruising flight, they have the edge over birds when it comes to manoeuvring. There is a direct relationship between kinematics and the aerodynamic performance, but there is still a lack of knowledge about how (and if) the bat controls the movements and shape (planform and camber) of the wing. Considering the relatively few bat species whose aerodynamic tracks have been characterized, there is scope for new discoveries and a need to study species representing more extreme positions in the bat morphospace. © 2015. Published by The Company of Biologists Ltd.

  9. Capital Flight from Russia

    OpenAIRE

    Prakash Loungani; Paolo Mauro

    2000-01-01

    This paper documents the scale of capital flight from Russia, compares it with that observed in other countries, and reviews policy options. The evidence from other countries suggests that capital flight can be reversed once reforms take hold. The paper argues that capital flight from Russia can only be curbed through a medium-term reform strategy aimed at improving governance and macroeconomic performance, and strengthening the banking system. Capital controls result in costly distortions an...

  10. Theseus in Flight

    Science.gov (United States)

    1996-01-01

    The twin pusher propeller-driven engines of the Theseus research aircraft can be clearly seen in this photo, taken during a 1996 research flight at NASA's Dryden Flight Research Center, Edwards, California. The Theseus aircraft, built and operated by Aurora Flight Sciences Corporation, Manassas, Virginia, was a unique aircraft flown at NASA's Dryden Flight Research Center, Edwards, California, under a cooperative agreement between NASA and Aurora. Dryden hosted the Theseus program, providing hangar space and range safety for flight testing. Aurora Flight Sciences was responsible for the actual flight testing, vehicle flight safety, and operation of the aircraft. The Theseus remotely piloted aircraft flew its maiden flight on May 24, 1996, at Dryden. During its sixth flight on November 12, 1996, Theseus experienced an in-flight structural failure that resulted in the loss of the aircraft. As of the beginning of the year 2000, Aurora had not rebuilt the aircraft. Theseus was built for NASA under an innovative, $4.9 million fixed-price contract by Aurora Flight Sciences Corporation and its partners, West Virginia University, Morgantown, West Virginia, and Fairmont State College, Fairmont, West Virginia. The twin-engine, unpiloted vehicle had a 140-foot wingspan, and was constructed largely of composite materials. Powered by two 80-horsepower, turbocharged piston engines that drove twin 9-foot-diameter propellers, Theseus was designed to fly autonomously at high altitudes, with takeoff and landing under the active control of a ground-based pilot in a ground control station 'cockpit.' With the potential ability to carry 700 pounds of science instruments to altitudes above 60,000 feet for durations of greater than 24 hours, Theseus was intended to support research in areas such as stratospheric ozone depletion and the atmospheric effects of future high-speed civil transport aircraft engines. Instruments carried aboard Theseus also would be able to validate satellite

  11. Flight research and testing

    Science.gov (United States)

    Putnam, Terrill W.; Ayers, Theodore G.

    1989-01-01

    Flight research and testing form a critical link in the aeronautic research and development chain. Brilliant concepts, elegant theories, and even sophisticated ground tests of flight vehicles are not sufficient to prove beyond a doubt that an unproven aeronautical concept will actually perform as predicted. Flight research and testing provide the ultimate proof that an idea or concept performs as expected. Ever since the Wright brothers, flight research and testing were the crucible in which aeronautical concepts were advanced and proven to the point that engineers and companies are willing to stake their future to produce and design aircraft. This is still true today, as shown by the development of the experimental X-30 aerospace plane. The Dryden Flight Research Center (Ames-Dryden) continues to be involved in a number of flight research programs that require understanding and characterization of the total airplane in all the aeronautical disciplines, for example the X-29. Other programs such as the F-14 variable-sweep transition flight experiment have focused on a single concept or discipline. Ames-Dryden also continues to conduct flight and ground based experiments to improve and expand the ability to test and evaluate advanced aeronautical concepts. A review of significant aeronautical flight research programs and experiments is presented to illustrate both the progress being made and the challenges to come.

  12. Flight Standards Automation System -

    Data.gov (United States)

    Department of Transportation — FAVSIS supports Flight Standards Service (AFS) by maintaining their information on entities such as air carriers, air agencies, designated airmen, and check airmen....

  13. Robust sampled-data control of hydraulic flight control actuators

    OpenAIRE

    Kliffken, Markus Gustav

    1997-01-01

    In todays flight-by-wire systems the primary flight control surfaces of modern commercial and transport aircraft are driven by electro hydraulic linear actuators. Changing flight conditions as well as nonlinear actuator dynamics may be interpreted as parameter uncertainties of the linear actuator model. This demands a robust design for the controller. Here the parameter space design is used for the direct sampled-data controller synthesis. Therefore, a static output controller is choosen, the...

  14. Evaluation of Small Unmanned Aircraft Flight Trajectory Accuracy

    Directory of Open Access Journals (Sweden)

    Ramūnas Kikutis

    2014-12-01

    Full Text Available Today small unmanned aircraft are being more widely adapted for practical tasks. These tasks require high reliability and flight path accuracy. For such aircraft we have to deal with the chalenge how to compensate external factors and how to ensure the accuracy of the flight trajectory according to new regulations and standards. In this paper, new regulations for the flights of small unmanned aircraft in Lithuanian air space are discussed. Main factors, which affect errors of the autonomous flight path tracking, are discussed too. The emphasis is on the wind factor and the flight path of Dubbin’s trajectories. Research was performed with mathematical-dynamic model of UAV and it was compared with theoretical calculations. All calculations and experiments were accomplished for the circular part of Dubbin’s paths when the airplane was trimmed for circular trajectory flight in calm conditions. Further, for such flight the wind influence was analysed.

  15. Pre-flight physical simulation test of HIMES reentry test vehicle

    Science.gov (United States)

    Kawaguchi, Jun'ichiro; Inatani, Yoshifumi; Yonemoto, Koichi; Hosokawa, Shigeru

    ISAS is now developing a small reentry test vehicle, which is 2m long with a 1.5m wing span and weighs about 170 kg, for the purpose of exploring high angle-of-attack aerodynamic attitude control issue in supersonic and hypersonic speed. The flight test, employing 'Rockoon' launch system, is planned as a preliminary design verification for a fully reusable winged rocket named HIMES (Highly Maneuverable Experimental Space) vehicle. This paper describes the results of preflight ground test using a motion table system. This ground system test is called 'physical simulation' aimed at: (1) functional verification of side-jet system, aerodynamic surface actuators, battery and onboard avionics; and (2) guidance and control law evaluation, in total hardware-in-the-loop system. The pressure of side-jet nozzles was measured to provide exact thrust characteristics of reaction control. The dynamics of vehicle motion was calculated in real-time by the ground simulation computer.

  16. ACSYNT inner loop flight control design study

    Science.gov (United States)

    Bortins, Richard; Sorensen, John A.

    1993-01-01

    The NASA Ames Research Center developed the Aircraft Synthesis (ACSYNT) computer program to synthesize conceptual future aircraft designs and to evaluate critical performance metrics early in the design process before significant resources are committed and cost decisions made. ACSYNT uses steady-state performance metrics, such as aircraft range, payload, and fuel consumption, and static performance metrics, such as the control authority required for the takeoff rotation and for landing with an engine out, to evaluate conceptual aircraft designs. It can also optimize designs with respect to selected criteria and constraints. Many modern aircraft have stability provided by the flight control system rather than by the airframe. This may allow the aircraft designer to increase combat agility, or decrease trim drag, for increased range and payload. This strategy requires concurrent design of the airframe and the flight control system, making trade-offs of performance and dynamics during the earliest stages of design. ACSYNT presently lacks means to implement flight control system designs but research is being done to add methods for predicting rotational degrees of freedom and control effector performance. A software module to compute and analyze the dynamics of the aircraft and to compute feedback gains and analyze closed loop dynamics is required. The data gained from these analyses can then be fed back to the aircraft design process so that the effects of the flight control system and the airframe on aircraft performance can be included as design metrics. This report presents results of a feasibility study and the initial design work to add an inner loop flight control system (ILFCS) design capability to the stability and control module in ACSYNT. The overall objective is to provide a capability for concurrent design of the aircraft and its flight control system, and enable concept designers to improve performance by exploiting the interrelationships between

  17. High-dynamic-range neutron time-of-flight detector used to infer the D(t,n){sup 4}He and D(d,n){sup 3}He reaction yield and ion temperature on OMEGA

    Energy Technology Data Exchange (ETDEWEB)

    Forrest, C. J., E-mail: cforrest@lle.rochester.edu; Glebov, V. Yu.; Goncharov, V. N.; Knauer, J. P.; Radha, P. B.; Regan, S. P.; Romanofsky, M. H.; Sangster, T. C.; Shoup, M. J.; Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)

    2016-11-15

    Upgraded microchannel-plate–based photomultiplier tubes (MCP-PMT’s) with increased stability to signal-shape linearity have been implemented on the 13.4-m neutron time-of-flight (nTOF) detector at the Omega Laser Facility. This diagnostic uses oxygenated xylene doped with diphenyloxazole C{sub 15}H{sub 11}NO + p-bis-(o-methylstyryl)-benzene (PPO + bis-MSB) wavelength shifting dyes and is coupled through four viewing ports to fast-gating MCP-PMT’s, each with a different gain to allow one to measure the light output over a dynamic range of 1 × 10{sup 6}. With these enhancements, the 13.4-m nTOF can measure the D(t,n){sup 4}He and D(d,n){sup 3}He reaction yields and average ion temperatures in a single line of sight. Once calibrated for absolute neutron sensitivity, the nTOF detectors can be used to measure the neutron yield from 1 × 10{sup 9} to 1 × 10{sup 14} and the ion temperature with an accuracy approaching 5% for both the D(t,n){sup 4}He and D(d,n){sup 3}He reactions.

  18. A computational fluid dynamics simulation of the hypersonic flight of the Pegasus(TM) vehicle using an artificial viscosity model and a nonlinear filtering method. M.S. Thesis

    Science.gov (United States)

    Mendoza, John Cadiz

    1995-01-01

    The computational fluid dynamics code, PARC3D, is tested to see if its use of non-physical artificial dissipation affects the accuracy of its results. This is accomplished by simulating a shock-laminar boundary layer interaction and several hypersonic flight conditions of the Pegasus(TM) launch vehicle using full artificial dissipation, low artificial dissipation, and the Engquist filter. Before the filter is applied to the PARC3D code, it is validated in one-dimensional and two-dimensional form in a MacCormack scheme against the Riemann and convergent duct problem. For this explicit scheme, the filter shows great improvements in accuracy and computational time as opposed to the nonfiltered solutions. However, for the implicit PARC3D code it is found that the best estimate of the Pegasus experimental heat fluxes and surface pressures is the simulation utilizing low artificial dissipation and no filter. The filter does improve accuracy over the artificially dissipative case but at a computational expense greater than that achieved by the low artificial dissipation case which has no computational time penalty and shows better results. For the shock-boundary layer simulation, the filter does well in terms of accuracy for a strong impingement shock but not as well for weaker shock strengths. Furthermore, for the latter problem the filter reduces the required computational time to convergence by 18.7 percent.

  19. Flight Test of L1 Adaptive Control Law: Offset Landings and Large Flight Envelope Modeling Work

    Science.gov (United States)

    Gregory, Irene M.; Xargay, Enric; Cao, Chengyu; Hovakimyan, Naira

    2011-01-01

    This paper presents new results of a flight test of the L1 adaptive control architecture designed to directly compensate for significant uncertain cross-coupling in nonlinear systems. The flight test was conducted on the subscale turbine powered Generic Transport Model that is an integral part of the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. The results presented include control law evaluation for piloted offset landing tasks as well as results in support of nonlinear aerodynamic modeling and real-time dynamic modeling of the departure-prone edges of the flight envelope.

  20. Dynamic-MLC leaf control utilizing on-flight intensity calculations: A robust method for real-time IMRT delivery over moving rigid targets

    International Nuclear Information System (INIS)

    McMahon, Ryan; Papiez, Lech; Rangaraj, Dharanipathy

    2007-01-01

    An algorithm is presented that allows for the control of multileaf collimation (MLC) leaves based entirely on real-time calculations of the intensity delivered over the target. The algorithm is capable of efficiently correcting generalized delivery errors without requiring the interruption of delivery (self-correcting trajectories), where a generalized delivery error represents anything that causes a discrepancy between the delivered and intended intensity profiles. The intensity actually delivered over the target is continually compared to its intended value. For each pair of leaves, these comparisons are used to guide the control of the following leaf and keep this discrepancy below a user-specified value. To demonstrate the basic principles of the algorithm, results of corrected delivery are shown for a leading leaf positional error during dynamic-MLC (DMLC) IMRT delivery over a rigid moving target. It is then shown that, with slight modifications, the algorithm can be used to track moving targets in real time. The primary results of this article indicate that the algorithm is capable of accurately delivering DMLC IMRT over a rigid moving target whose motion is (1) completely unknown prior to delivery and (2) not faster than the maximum MLC leaf velocity over extended periods of time. These capabilities are demonstrated for clinically derived intensity profiles and actual tumor motion data, including situations when the target moves in some instances faster than the maximum admissible MLC leaf velocity. The results show that using the algorithm while calculating the delivered intensity every 50 ms will provide a good level of accuracy when delivering IMRT over a rigid moving target translating along the direction of MLC leaf travel. When the maximum velocities of the MLC leaves and target were 4 and 4.2 cm/s, respectively, the resulting error in the two intensity profiles used was 0.1±3.1% and -0.5±2.8% relative to the maximum of the intensity profiles. For

  1. Machine Learning for Flapping Wing Flight Control

    NARCIS (Netherlands)

    Goedhart, Menno; van Kampen, E.; Armanini, S.F.; de Visser, C.C.; Chu, Q.

    2018-01-01

    Flight control of Flapping Wing Micro Air Vehicles is challenging, because of their complex dynamics and variability due to manufacturing inconsistencies. Machine Learning algorithms can be used to tackle these challenges. A Policy Gradient algorithm is used to tune the gains of a

  2. Recent developments in the remote radio control of insect flight.

    Science.gov (United States)

    Sato, Hirotaka; Maharbiz, Michel M

    2010-01-01

    The continuing miniaturization of digital circuits and the development of low power radio systems coupled with continuing studies into the neurophysiology and dynamics of insect flight are enabling a new class of implantable interfaces capable of controlling insects in free flight for extended periods. We provide context for these developments, review the state-of-the-art and discuss future directions in this field.

  3. X-43A Flight Controls

    Science.gov (United States)

    Baumann, Ethan

    2006-01-01

    A viewgraph presentation detailing X-43A Flight controls at NASA Dryden Flight Research Center is shown. The topics include: 1) NASA Dryden, Overview and current and recent flight test programs; 2) Unmanned Aerial Vehicle Synthetic Aperture Radar (UAVSAR) Program, Program Overview and Platform Precision Autopilot; and 3) Hyper-X Program, Program Overview, X-43A Flight Controls and Flight Results.

  4. Analysis of RAE-B attitude data

    Science.gov (United States)

    Hedland, D. A.; Degonia, P. K.

    1975-01-01

    Attempts made to obtain a description of the in-orbit dynamic behavior of the RAE-B spacecraft and account for the discrepancies between predicted and actual in-orbit performance are reported. In particular, attitude dynamics during the final despin operations in lunar orbit, throughout all deployment operations, and into the final steady state mission mode were investigated. Attempts made to match computer simulation results to the observed equilibrium data are discussed. Due to a damaged antenna boom and the unavailability of sufficient attitude and dynamics data, most of the objectives were not realized.

  5. Simulation and experimental research on line throwing rocket with flight

    Directory of Open Access Journals (Sweden)

    Wen-bin Gu

    2014-06-01

    Full Text Available The finite segment method is used to model the line throwing rocket system. A dynamic model of line throwing rocket with flight motion based on Kane's method is presented by the kinematics description of the system and the consideration of the forces acting on the system. The experiment designed according to the parameters of the dynamic model is made. The simulation and experiment results, such as range, velocity and flight time, are compared and analyzed. The simulation results are basically agreed with the test data, which shows that the flight motion of the line throwing rocket can be predicted by the dynamic model. A theoretical model and guide for the further research on the disturbance of rope and the guidance, flight control of line throwing rocket are provided by the dynamic modeling.

  6. Performance evaluation and design of flight vehicle control systems

    CERN Document Server

    Falangas, Eric T

    2015-01-01

    This book will help students, control engineers and flight dynamics analysts to model and conduct sophisticated and systemic analyses of early flight vehicle designs controlled with multiple types of effectors and to design and evaluate new vehicle concepts in terms of satisfying mission and performance goals. Performance Evaluation and Design of Flight Vehicle Control Systems begins by creating a dynamic model of a generic flight vehicle that includes a range of elements from airplanes and launch vehicles to re-entry vehicles and spacecraft. The models may include dynamic effects dealing with structural flexibility, as well as dynamic coupling between structures and actuators, propellant sloshing, and aeroelasticity, and they are typically used for control analysis and design. The book shows how to efficiently combine different types of effectors together, such as aero-surfaces, TVC, throttling engines and RCS, to operate as a system by developing a mixing logic atrix. Methods of trimming a vehicle controll...

  7. Insect flight on fluid interfaces: a chaotic interfacial oscillator

    Science.gov (United States)

    Mukundarajan, Haripriya; Prakash, Manu

    2013-11-01

    Flight is critical to the dominance of insect species on our planet, with about 98 percent of insect species having wings. How complex flight control systems developed in insects is unknown, and arboreal or aquatic origins have been hypothesized. We examine the biomechanics of aquatic origins of flight. We recently reported discovery of a novel mode of ``2D flight'' in Galerucella beetles, which skim along an air-water interface using flapping wing flight. This unique flight mode is characterized by a balance between capillary forces from the interface and biomechanical forces exerted by the flapping wings. Complex interactions on the fluid interface form capillary wave trains behind the insect, and produce vertical oscillations at the surface due to non-linear forces arising from deformation of the fluid meniscus. We present both experimental observations of 2D flight kinematics and a dynamic model explaining the observed phenomena. Careful examination of this interaction predicts the chaotic nature of interfacial flight and takeoff from the interface into airborne flight. The role of wingbeat frequency, stroke plane angle and body angle in determining transition between interfacial and fully airborne flight is highlighted, shedding light on the aquatic theory of flight evolution.

  8. Automated Attitude Sensor Calibration: Progress and Plans

    Science.gov (United States)

    Sedlak, Joseph; Hashmall, Joseph

    2004-01-01

    This paper describes ongoing work a NASA/Goddard Space Flight Center to improve the quality of spacecraft attitude sensor calibration and reduce costs by automating parts of the calibration process. The new calibration software can autonomously preview data quality over a given time span, select a subset of the data for processing, perform the requested calibration, and output a report. This level of automation is currently being implemented for two specific applications: inertial reference unit (IRU) calibration and sensor alignment calibration. The IRU calibration utility makes use of a sequential version of the Davenport algorithm. This utility has been successfully tested with simulated and actual flight data. The alignment calibration is still in the early testing stage. Both utilities will be incorporated into the institutional attitude ground support system.

  9. Simulation and experimental research on line throwing rocket with flight

    OpenAIRE

    Wen-bin Gu; Ming Lu; Jian-qing Liu; Qin-xing Dong; Zhen-xiong Wang; Jiang-hai Chen

    2014-01-01

    The finite segment method is used to model the line throwing rocket system. A dynamic model of line throwing rocket with flight motion based on Kane's method is presented by the kinematics description of the system and the consideration of the forces acting on the system. The experiment designed according to the parameters of the dynamic model is made. The simulation and experiment results, such as range, velocity and flight time, are compared and analyzed. The simulation results are basicall...

  10. Integrated Neural Flight and Propulsion Control System

    Science.gov (United States)

    Kaneshige, John; Gundy-Burlet, Karen; Norvig, Peter (Technical Monitor)

    2001-01-01

    This paper describes an integrated neural flight and propulsion control system. which uses a neural network based approach for applying alternate sources of control power in the presence of damage or failures. Under normal operating conditions, the system utilizes conventional flight control surfaces. Neural networks are used to provide consistent handling qualities across flight conditions and for different aircraft configurations. Under damage or failure conditions, the system may utilize unconventional flight control surface allocations, along with integrated propulsion control, when additional control power is necessary for achieving desired flight control performance. In this case, neural networks are used to adapt to changes in aircraft dynamics and control allocation schemes. Of significant importance here is the fact that this system can operate without emergency or backup flight control mode operations. An additional advantage is that this system can utilize, but does not require, fault detection and isolation information or explicit parameter identification. Piloted simulation studies were performed on a commercial transport aircraft simulator. Subjects included both NASA test pilots and commercial airline crews. Results demonstrate the potential for improving handing qualities and significantly increasing survivability rates under various simulated failure conditions.

  11. Fused Reality for Enhanced Flight Test Capabilities

    Science.gov (United States)

    Bachelder, Ed; Klyde, David

    2011-01-01

    The feasibility of using Fused Reality-based simulation technology to enhance flight test capabilities has been investigated. In terms of relevancy to piloted evaluation, there remains no substitute for actual flight tests, even when considering the fidelity and effectiveness of modern ground-based simulators. In addition to real-world cueing (vestibular, visual, aural, environmental, etc.), flight tests provide subtle but key intangibles that cannot be duplicated in a ground-based simulator. There is, however, a cost to be paid for the benefits of flight in terms of budget, mission complexity, and safety, including the need for ground and control-room personnel, additional aircraft, etc. A Fused Reality(tm) (FR) Flight system was developed that allows a virtual environment to be integrated with the test aircraft so that tasks such as aerial refueling, formation flying, or approach and landing can be accomplished without additional aircraft resources or the risk of operating in close proximity to the ground or other aircraft. Furthermore, the dynamic motions of the simulated objects can be directly correlated with the responses of the test aircraft. The FR Flight system will allow real-time observation of, and manual interaction with, the cockpit environment that serves as a frame for the virtual out-the-window scene.

  12. Attitude control system for a lightweight flapping wing MAV.

    Science.gov (United States)

    Tijmons, Sjoerd; Karásek, Matěj; de Croon, G C H E

    2018-03-14

    Robust attitude control is an essential aspect of research on autonomous flight of flapping wing Micro Air Vehicles. The mechanical solutions by which the necessary control moments are realised come at the price of extra weight and possible loss of aerodynamic efficiency. Stable flight of these vehicles has been shown by several designs using a conventional tail, but also by tailless designs that use active control of the wings. In this study a control mechanism is proposed that provides active control over the wings. The mechanism improves vehicle stability and agility by generation of control moments for roll, pitch and yaw. Its effectiveness is demonstrated by static measurements around all the three axes. Flight test results confirm that the attitude of the test vehicle, including a tail, can be successfully controlled in slow forward flight conditions. Furthermore, the flight envelope is extended with robust hovering and the ability to reverse the flight direction using a small turn space. This capability is very important for autonomous flight capabilities such as obstacle avoidance. Finally, it is demonstrated that the proposed control mechanism allows for tailless hovering flight. © 2018 IOP Publishing Ltd.

  13. Ares I Flight Control System Overview

    Science.gov (United States)

    Hall, Charles; Lee, Chong; Jackson, Mark; Whorton, Mark; West, mark; Brandon, Jay; Hall, Rob A.; Jang, Jimmy; Bedrossian, Naz; Compton, Jimmy; hide

    2008-01-01

    This paper describes the control challenges posed by the Ares I vehicle, the flight control system design and performance analyses used to test and verify the design. The major challenges in developing the control system are structural dynamics, dynamic effects from the powerful first stage booster, aerodynamics, first stage separation and large uncertainties in the dynamic models for all these. Classical control techniques were employed using innovative methods for structural mode filter design and an anti-drift feature to compensate for translational and rotational disturbances. This design was coded into an integrated vehicle flight simulation and tested by Monte Carlo methods. The product of this effort is a linear, robust controller design that is easy to implement, verify and test.

  14. E-Psychology: Consumers' Attitude

    Science.gov (United States)

    Jordanova, Malina; Vasileva, Lidia; Rasheva, Maximka; Bojinova, Rumiana

    Securing psychological supervision, consultations and help during long lasting flights is vital condition for success. That's why, knowing in details consumers (clients) attitude toward virtual psychology services is essential. Knowledge gained during nowadays studies on Earth will definitely help in the preparation for the future. The presentation focuses on results of a longitudinal survey assessing clients' attitudes toward e-psychology service. The first part of the survey was performed in spring 2006, while the second - in 2008. The study is part of an ongoing project OHN 1514/2005, funded by National Science Fund, Bulgaria. Project's strategic goal is to develop and offer a virtual high quality psychological service to people from remotes areas that have no contact with licensed psychologist. The project enables experts to communicate directly with clients and perform remote consultations, supervision, etc. The objective of this presentation is to report changes and trends in clients' attitude towards innovative virtual psychology care. Both parts of the survey involved men and women between 19 and 70 year, who defend various opinions on the application of virtual technologies for healthcare. The sample is stratifies for age, gender, education level.

  15. Development of a flight software testing methodology

    Science.gov (United States)

    Mccluskey, E. J.; Andrews, D. M.

    1985-01-01

    The research to develop a testing methodology for flight software is described. An experiment was conducted in using assertions to dynamically test digital flight control software. The experiment showed that 87% of typical errors introduced into the program would be detected by assertions. Detailed analysis of the test data showed that the number of assertions needed to detect those errors could be reduced to a minimal set. The analysis also revealed that the most effective assertions tested program parameters that provided greater indirect (collateral) testing of other parameters. In addition, a prototype watchdog task system was built to evaluate the effectiveness of executing assertions in parallel by using the multitasking features of Ada.

  16. Kalman Filter for Spinning Spacecraft Attitude Estimation

    Science.gov (United States)

    Markley, F. Landis; Sedlak, Joseph E.

    2008-01-01

    This paper presents a Kalman filter using a seven-component attitude state vector comprising the angular momentum components in an inertial reference frame, the angular momentum components in the body frame, and a rotation angle. The relatively slow variation of these parameters makes this parameterization advantageous for spinning spacecraft attitude estimation. The filter accounts for the constraint that the magnitude of the angular momentum vector is the same in the inertial and body frames by employing a reduced six-component error state. Four variants of the filter, defined by different choices for the reduced error state, are tested against a quaternion-based filter using simulated data for the THEMIS mission. Three of these variants choose three of the components of the error state to be the infinitesimal attitude error angles, facilitating the computation of measurement sensitivity matrices and causing the usual 3x3 attitude covariance matrix to be a submatrix of the 6x6 covariance of the error state. These variants differ in their choice for the other three components of the error state. The variant employing the infinitesimal attitude error angles and the angular momentum components in an inertial reference frame as the error state shows the best combination of robustness and efficiency in the simulations. Attitude estimation results using THEMIS flight data are also presented.

  17. Quaternions in collective dynamics

    OpenAIRE

    Degond, Pierre; Frouvelle, Amic; Merino-Aceituno, Sara; Trescases, Ariane

    2017-01-01

    We introduce a model of multi-agent dynamics for self-organised motion; individuals travel at a constant speed while trying to adopt the averaged body attitude of their neighbours. The body attitudes are represented through unitary quaternions. We prove the correspondance with the model presented in a previous work by the three first authors where the body attitudes are represented by rotation matrices. Differently from this previous work, the individual based model (IBM) introduced here is b...

  18. Quaternions in collective dynamics

    OpenAIRE

    Degond, Pierre; Frouvelle, Amic; Merino-Aceituno, Sara; Trescases, Ariane

    2018-01-01

    We introduce a model of multi-agent dynamics for self-organised motion; individuals travel at a constant speed while trying to adopt the averaged body attitude of their neighbours. The body attitudes are represented through unitary quaternions. We prove the correspondance with the model presented in Ref. [16] where the body attitudes are represented by rotation matrices. Differently from this previous work, the individual based model (IBM) introduced here is based on nematic (rather than pola...

  19. Initial Flight Test of the Production Support Flight Control Computers at NASA Dryden Flight Research Center

    Science.gov (United States)

    Carter, John; Stephenson, Mark

    1999-01-01

    The NASA Dryden Flight Research Center has completed the initial flight test of a modified set of F/A-18 flight control computers that gives the aircraft a research control law capability. The production support flight control computers (PSFCC) provide an increased capability for flight research in the control law, handling qualities, and flight systems areas. The PSFCC feature a research flight control processor that is "piggybacked" onto the baseline F/A-18 flight control system. This research processor allows for pilot selection of research control law operation in flight. To validate flight operation, a replication of a standard F/A-18 control law was programmed into the research processor and flight-tested over a limited envelope. This paper provides a brief description of the system, summarizes the initial flight test of the PSFCC, and describes future experiments for the PSFCC.

  20. Core Flight Software

    Data.gov (United States)

    National Aeronautics and Space Administration — The AES Core Flight Software (CFS) project purpose is to analyze applicability, and evolve and extend the reusability of the CFS system originally developed by...

  1. Flapping wing flight can save aerodynamic power compared to steady flight.

    Science.gov (United States)

    Pesavento, Umberto; Wang, Z Jane

    2009-09-11

    Flapping flight is more maneuverable than steady flight. It is debated whether this advantage is necessarily accompanied by a trade-off in the flight efficiency. Here we ask if any flapping motion exists that is aerodynamically more efficient than the optimal steady motion. We solve the Navier-Stokes equation governing the fluid dynamics around a 2D flapping wing, and determine the minimal aerodynamic power needed to support a specified weight. While most flapping wing motions are more costly than the optimal steady wing motion, we find that optimized flapping wing motions can save up to 27% of the aerodynamic power required by the optimal steady flight. We explain the cause of this energetic advantage.

  2. Adaptive structures flight experiments

    Science.gov (United States)

    Martin, Maurice

    The topics are presented in viewgraph form and include the following: adaptive structures flight experiments; enhanced resolution using active vibration suppression; Advanced Controls Technology Experiment (ACTEX); ACTEX program status; ACTEX-2; ACTEX-2 program status; modular control patch; STRV-1b Cryocooler Vibration Suppression Experiment; STRV-1b program status; Precision Optical Bench Experiment (PROBE); Clementine Spacecraft Configuration; TECHSAT all-composite spacecraft; Inexpensive Structures and Materials Flight Experiment (INFLEX); and INFLEX program status.

  3. Magnesium and Space Flight

    Directory of Open Access Journals (Sweden)

    Scott M. Smith

    2015-12-01

    Full Text Available Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in 43 astronauts (34 male, 9 female; 47 ± 5 years old, mean ± SD before, during, and after 4–6-month space missions. We also studied individuals participating in a ground analog of space flight (head-down-tilt bed rest; n = 27 (17 male, 10 female, 35 ± 7 years old. We evaluated serum concentration and 24-h urinary excretion of magnesium, along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-day space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4–6-month space missions.

  4. Magnesium and Space Flight

    Science.gov (United States)

    Smith, Scott M.; Zwart, Sara R.

    2015-01-01

    Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in 43 astronauts (34 male, 9 female; 47 ± 5 years old, mean ± SD) before, during, and after 4–6-month space missions. We also studied individuals participating in a ground analog of space flight (head-down-tilt bed rest; n = 27 (17 male, 10 female), 35 ± 7 years old). We evaluated serum concentration and 24-h urinary excretion of magnesium, along with estimates of tissue magnesium status from sublingual cells. Serum magnesium increased late in flight, while urinary magnesium excretion was higher over the course of 180-day space missions. Urinary magnesium increased during flight but decreased significantly at landing. Neither serum nor urinary magnesium changed during bed rest. For flight and bed rest, significant correlations existed between the area under the curve of serum and urinary magnesium and the change in total body bone mineral content. Tissue magnesium concentration was unchanged after flight and bed rest. Increased excretion of magnesium is likely partially from bone and partially from diet, but importantly, it does not come at the expense of muscle tissue stores. While further study is needed to better understand the implications of these findings for longer space exploration missions, magnesium homeostasis and tissue status seem well maintained during 4–6-month space missions. PMID:26670248

  5. Dynamics of Variable Mass Systems

    Science.gov (United States)

    Eke, Fidelis O.

    1998-01-01

    This report presents the results of an investigation of the effects of mass loss on the attitude behavior of spinning bodies in flight. The principal goal is to determine whether there are circumstances under which the motion of variable mass systems can become unstable in the sense that their transverse angular velocities become unbounded. Obviously, results from a study of this kind would find immediate application in the aerospace field. The first part of this study features a complete and mathematically rigorous derivation of a set of equations that govern both the translational and rotational motions of general variable mass systems. The remainder of the study is then devoted to the application of the equations obtained to a systematic investigation of the effect of various mass loss scenarios on the dynamics of increasingly complex models of variable mass systems. It is found that mass loss can have a major impact on the dynamics of mechanical systems, including a possible change in the systems stability picture. Factors such as nozzle geometry, combustion chamber geometry, propellant's initial shape, size and relative mass, and propellant location can all have important influences on the system's dynamic behavior. The relative importance of these parameters on-system motion are quantified in a way that is useful for design purposes.

  6. Morphing flight control surface for advanced flight performance

    Science.gov (United States)

    Detrick, Matt; Kwak, Seung-Keon; Yoon, Hwan-Sik

    2006-03-01

    A novel Morphing Flight Control Surface (MFCS) system has been developed. The distinction of this research effort is that the SenAnTech team has incorporated our innovative Highly Deformable Mechanism (HDM) into our MFCS. The feasibility of this novel technology for deformable wing structures, such as airfoil shaping, warping or twisting with a flexure-based high displacement PZT actuator has been demonstrated via computational simulations such as Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD). CFD was implemented to verify the accuracy of the complex potential flow theory for this application. Then, complex potential flow theory, kinematics, geometry, and static force analysis were incorporated into a multidisciplinary GUI simulation tool. This tool has been used to aid the design of the MFCS. The results show that we can achieve up to five degrees of wing twisting with our proposed system, while using minimal volume within the wing and adding little weight.

  7. Analysis of shadowing effects on MIR photovoltaic and solar dynamic power systems

    Science.gov (United States)

    Fincannon, James

    1995-01-01

    The NASA Lewis Research Center is currently working with RSC-Energia, the Russian Space Agency, and Allied Signal in developing a flight demonstration solar dynamic power system. This type of power system is dependent upon solar flux that is reflected and concentrated into a thermal storage system to provide the thermal energy input to a closed-cycle Brayton heat engine. The solar dynamic unit will be flown on the Russian Mir space station in anticipation of use on the International Space Station Alpha. By the time the power system is launched, the Mir will be a spatially complex configuration which will have, in addition to the three-gimbaled solar dynamic unit, eleven solar array wings that are either fixed or track the Sun along one axis and a variety or repositionable habitation and experiment modules. The proximity of arrays to modules creates a situation which makes it highly probable that there will be varying solar flux due to shadowing on the solar dynamic unit and some of the arrays throughout the orbit. Shadowing causes fluctuations in the power output from the arrays and the solar dynamic power system, thus reducing the energy capabilities of the spacecraft. An assessment of the capabilities of the power system under these conditions is an important part in influencing the design and operations of the spacecraft and predicting its energy performance. This paper describes the results obtained from using the Orbiting Spacecraft Shadowing Analysis Station program that was integrated into the Station Power Analysis for Capability Evaluation (SPACE) electrical power system computer program. OSSA allows one to consider the numerous complex factors for analyzing the shadowing effects on the electrical power system including the variety of spacecraft hardware geometric configurations, yearly and daily orbital variations in the vehicle attitude and orbital maneuvers (for communications coverage, payload pointing requirements and rendezvous/docking with other

  8. Paresev in flight with pilot Milt Thompson

    Science.gov (United States)

    1964-01-01

    This movie clip runs 37 seconds in length and begins with a shot from the chase plane of NASA Dryden test pilot Milt Thompson at the controls of the Paresev, then the onboard view from the pilot's seat and finally bringing the Paresev in for a landing on the dry lakebed at Edwards AFB. The Paresev (Paraglider Rescue Vehicle) was an indirect outgrowth of kite-parachute studies by NACA Langley engineer Francis M. Rogallo. In early 1960's the 'Rogallo wing' seemed an excellent means of returning a spacecraft to Earth. The delta wing design was patented by Mr. Rogallo. In May 1961, Robert R. Gilruth, director of the NASA Space Task Group, requested studies of an inflatable Rogallo-type 'Parawing' for spacecraft. Several companies responded; North American Aviation, Downey, California, produced the most acceptable concept and development was contracted to that company. In November 1961 NASA Headquarters launched a paraglider development program, with Langley doing wind tunnel studies and the NASA Flight Research Center supporting the North American test program. The North American concept was a capsule-type vehicle with a stowed 'parawing' that could be deployed and controlled from within for a landing more like an airplane instead of a 'splash down' in the ocean. The logistics became enormous and the price exorbitant, plus NASA pilots and engineers felt some baseline experience like building a vehicle and flying a Parawing should be accomplished first. The Paresev (Paraglider Research Vehicle) was used to gain in-flight experience with four different membranes (wings), and was not used to develop the more complicated inflatable deployment system. The Paresev was designed by Charles Richard, of the Flight Research Center Vehicle and System Dynamics Branch, with the rest of the team being: engineers, Richard Klein, Gary Layton, John Orahood, and Joe Wilson; from the Maintenance and Manufacturing Branch: Frank Fedor, LeRoy Barto; Victor Horton as Project Manager, with

  9. Generation of the pitch moment during the controlled flight after takeoff of fruitflies.

    Directory of Open Access Journals (Sweden)

    Mao Wei Chen

    Full Text Available In the present paper, the controlled flight of fruitflies after voluntary takeoff is studied. Wing and body kinematics of the insects after takeoff are measured using high-speed video techniques, and the aerodynamic force and moment are calculated by the computational fluid dynamics method based on the measured data. How the control moments are generated is analyzed by correlating the computed moments with the wing kinematics. A fruit-fly has a large pitch-up angular velocity owing to the takeoff jump and the fly controls its body attitude by producing pitching moments. It is found that the pitching moment is produced by changes in both the aerodynamic force and the moment arm. The change in the aerodynamic force is mainly due to the change in angle of attack. The change in the moment arm is mainly due to the change in the mean stroke angle and deviation angle, and the deviation angle plays a more important role than the mean stroke angle in changing the moment arm (note that change in deviation angle implies variation in the position of the aerodynamic stroke plane with respect to the anatomical stroke plane. This is unlike the case of fruitflies correcting pitch perturbations in steady free flight, where they produce pitching moment mainly by changes in mean stroke angle.

  10. Generation of the pitch moment during the controlled flight after takeoff of fruitflies.

    Science.gov (United States)

    Chen, Mao Wei; Wu, Jiang Hao; Sun, Mao

    2017-01-01

    In the present paper, the controlled flight of fruitflies after voluntary takeoff is studied. Wing and body kinematics of the insects after takeoff are measured using high-speed video techniques, and the aerodynamic force and moment are calculated by the computational fluid dynamics method based on the measured data. How the control moments are generated is analyzed by correlating the computed moments with the wing kinematics. A fruit-fly has a large pitch-up angular velocity owing to the takeoff jump and the fly controls its body attitude by producing pitching moments. It is found that the pitching moment is produced by changes in both the aerodynamic force and the moment arm. The change in the aerodynamic force is mainly due to the change in angle of attack. The change in the moment arm is mainly due to the change in the mean stroke angle and deviation angle, and the deviation angle plays a more important role than the mean stroke angle in changing the moment arm (note that change in deviation angle implies variation in the position of the aerodynamic stroke plane with respect to the anatomical stroke plane). This is unlike the case of fruitflies correcting pitch perturbations in steady free flight, where they produce pitching moment mainly by changes in mean stroke angle.

  11. DAST in Flight

    Science.gov (United States)

    1980-01-01

    The modified BQM-34 Firebee II drone with Aeroelastic Research Wing (ARW-1), a supercritical airfoil, during a 1980 research flight. The remotely-piloted vehicle, which was air launched from NASA's NB-52B mothership, participated in the Drones for Aerodynamic and Structural Testing (DAST) program which ran from 1977 to 1983. The DAST 1 aircraft (Serial #72-1557), pictured, crashed on 12 June 1980 after its right wing ripped off during a test flight near Cuddeback Dry Lake, California. The crash occurred on the modified drone's third free flight. These are the image contact sheets for each image resolution of the NASA Dryden Drones for Aerodynamic and Structural Testing (DAST) Photo Gallery. From 1977 to 1983, the Dryden Flight Research Center, Edwards, California, (under two different names) conducted the DAST Program as a high-risk flight experiment using a ground-controlled, pilotless aircraft. Described by NASA engineers as a 'wind tunnel in the sky,' the DAST was a specially modified Teledyne-Ryan BQM-34E/F Firebee II supersonic target drone that was flown to validate theoretical predictions under actual flight conditions in a joint project with the Langley Research Center, Hampton, Virginia. The DAST Program merged advances in electronic remote control systems with advances in airplane design. Drones (remotely controlled, missile-like vehicles initially developed to serve as gunnery targets) had been deployed successfully during the Vietnamese conflict as reconnaissance aircraft. After the war, the energy crisis of the 1970s led NASA to seek new ways to cut fuel use and improve airplane efficiency. The DAST Program's drones provided an economical, fuel-conscious method for conducting in-flight experiments from a remote ground site. DAST explored the technology required to build wing structures with less than normal stiffness. This was done because stiffness requires structural weight but ensures freedom from flutter-an uncontrolled, divergent oscillation of

  12. The use of x-ray pulsar-based navigation method for interplanetary flight

    Science.gov (United States)

    Yang, Bo; Guo, Xingcan; Yang, Yong

    2009-07-01

    As interplanetary missions are increasingly complex, the existing unique mature interplanetary navigation method mainly based on radiometric tracking techniques of Deep Space Network can not meet the rising demands of autonomous real-time navigation. This paper studied the applications for interplanetary flights of a new navigation technology under rapid development-the X-ray pulsar-based navigation for spacecraft (XPNAV), and valued its performance with a computer simulation. The XPNAV is an excellent autonomous real-time navigation method, and can provide comprehensive navigation information, including position, velocity, attitude, attitude rate and time. In the paper the fundamental principles and time transformation of the XPNAV were analyzed, and then the Delta-correction XPNAV blending the vehicles' trajectory dynamics with the pulse time-of-arrival differences at nominal and estimated spacecraft locations within an Unscented Kalman Filter (UKF) was discussed with a background mission of Mars Pathfinder during the heliocentric transferring orbit. The XPNAV has an intractable problem of integer pulse phase cycle ambiguities similar to the GPS carrier phase navigation. This article innovatively proposed the non-ambiguity assumption approach based on an analysis of the search space array method to resolve pulse phase cycle ambiguities between the nominal position and estimated position of the spacecraft. The simulation results show that the search space array method are computationally intensive and require long processing time when the position errors are large, and the non-ambiguity assumption method can solve ambiguity problem quickly and reliably. It is deemed that autonomous real-time integrated navigation system of the XPNAV blending with DSN, celestial navigation, inertial navigation and so on will be the development direction of interplanetary flight navigation system in the future.

  13. Satellite Attitude Control System Simulator

    Directory of Open Access Journals (Sweden)

    G.T. Conti

    2008-01-01

    Full Text Available Future space missions will involve satellites with great autonomy and stringent pointing precision, requiring of the Attitude Control Systems (ACS with better performance than before, which is function of the control algorithms implemented on board computers. The difficulties for developing experimental ACS test is to obtain zero gravity and torque free conditions similar to the SCA operate in space. However, prototypes for control algorithms experimental verification are fundamental for space mission success. This paper presents the parameters estimation such as inertia matrix and position of mass centre of a Satellite Attitude Control System Simulator (SACSS, using algorithms based on least square regression and least square recursive methods. Simulations have shown that both methods have estimated the system parameters with small error. However, the least square recursive methods have performance more adequate for the SACSS objectives. The SACSS platform model will be used to do experimental verification of fundamental aspects of the satellite attitude dynamics and design of different attitude control algorithm.

  14. Capital Flight and Economic Performance

    OpenAIRE

    Beja, Edsel Jr.

    2007-01-01

    Capital flight aggravates resource constraints and contributes to undermine long-term economic growth. Counterfactual calculations on the Philippines suggest that capital flight contributed to lower the quality of long-term economic growth. Sustained capital flight over three decades means that capital flight had a role for the Philippines to lose the opportunities to achieve economic takeoff. Unless decisive policy actions are taken up to address enduring capital flight and manage the macroe...

  15. Recent estimates of capital flight

    OpenAIRE

    Claessens, Stijn; Naude, David

    1993-01-01

    Researchers and policymakers have in recent years paid considerable attention to the phenomenon of capital flight. Researchers have focused on four questions: What concept should be used to measure capital flight? What figure for capital flight will emerge, using this measure? Can the occurrence and magnitude of capital flight be explained by certain (economic) variables? What policy changes can be useful to reverse capital flight? The authors focus strictly on presenting estimates of capital...

  16. Perseus Post-flight

    Science.gov (United States)

    1991-01-01

    Crew members check out the Perseus proof-of-concept vehicle on Rogers Dry Lake, adjacent to the Dryden Flight Research Center, Edwards, California, after a test flight in 1991. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third generation of the Perseus design, which began with the Perseus Proof-Of-Concept aircraft. Perseus was initially developed as part of NASA's Small High-Altitude Science Aircraft (SHASA) program, which later evolved

  17. Eclipse takeoff and flight

    Science.gov (United States)

    1998-01-01

    This 25-second clip shows the QF-106 'Delta Dart' tethered to the USAF C-141A during takeoff and in flight. NASA Dryden Flight Research Center, Edwards, California, supported a Kelly Space and Technology, Inc. (KST)/U.S. Air Force project known as Eclipse, which demonstrated a reusable tow launch vehicle concept. The purpose of the project was to demonstrate a reusable tow launch vehicle concept that had been conceived and patented by KST. Kelly Space obtained a contract with the USAF Research Laboratory for the tow launch demonstration project under the Small Business Innovation Research (SBIR) program. The USAF SBIR contract included the modifications to turn the QF-106 into the Experimental Demonstrator #1 (EXD-01), and the C141A aircraft to incorporate the tow provisions to link the two aircraft, as well as conducting flight tests. The demonstration consisted of ground and flight tests. These tests included a Combined Systems Test of both airplanes joined by a tow rope, a towed taxi test, and six towed flights. The primary goal of the project was demonstrating the tow phase of the Eclipse concept using a scaled-down tow aircraft (C-141A) and a representative aerodynamically-shaped aircraft (QF-106A) as a launch vehicle. This was successfully accomplished. On December 20, 1997, NASA research pilot Mark Stucky flew a QF-106 on the first towed flight behind an Air Force C-141 in the joint Eclipse project with KST to demonstrate the reusable tow launch vehicle concept developed by KST. Kelly hoped to use the data from the tow tests to validate a tow-to-launch procedure for reusable space launch vehicles. Stucky flew six successful tow tests between December 1997 and February 6, 1998. On February 6, 1998, the sixth and final towed flight brought the project to a successful completion. Preliminary flight results determined that the handling qualities of the QF-106 on tow were very stable; actual flight measured values of tow rope tension were well within predictions

  18. Aerodynamics of bird flight

    Directory of Open Access Journals (Sweden)

    Dvořák Rudolf

    2016-01-01

    Full Text Available Unlike airplanes birds must have either flapping or oscillating wings (the hummingbird. Only such wings can produce both lift and thrust – two sine qua non attributes of flying.The bird wings have several possibilities how to obtain the same functions as airplane wings. All are realized by the system of flight feathers. Birds have also the capabilities of adjusting the shape of the wing according to what the immediate flight situation demands, as well as of responding almost immediately to conditions the flow environment dictates, such as wind gusts, object avoidance, target tracking, etc. In bird aerodynamics also the tail plays an important role. To fly, wings impart downward momentum to the surrounding air and obtain lift by reaction. How this is achieved under various flight situations (cruise flight, hovering, landing, etc., and what the role is of the wing-generated vortices in producing lift and thrust is discussed.The issue of studying bird flight experimentally from in vivo or in vitro experiments is also briefly discussed.

  19. 77 FR 69569 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: Pitch and...

    Science.gov (United States)

    2012-11-20

    ... attitude protection functions through the normal modes of the electronic flight control system that will...-1211; Notice No. 25-12-10-SC] Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: Pitch and Roll Limiting Functions AGENCY: Federal Aviation Administration (FAA), DOT...

  20. Group Effects on Individual Attitudes Toward Social Responsibility.

    Science.gov (United States)

    Secchi, Davide; Bui, Hong T M

    2018-01-01

    This study uses a quasi-experimental design to investigate what happens to individual socially responsible attitudes when they are exposed to group dynamics. Findings show that group engagement increases individual attitudes toward social responsibility. We also found that individuals with low attitudes toward social responsibility are more likely to change their opinions when group members show more positive attitudes toward social responsibility. Conversely, individuals with high attitudes do not change much, independent of group characteristics. To better analyze the effect of group dynamics, the study proposes to split social responsibility into relative and absolute components. Findings show that relative social responsibility is correlated with but different from absolute social responsibility although the latter is more susceptible than the former to group dynamics.

  1. Perseus in Flight

    Science.gov (United States)

    1991-01-01

    The Perseus proof-of-concept vehicle flies over Rogers Dry Lake at the Dryden Flight Research Center, Edwards, California, to test basic design concepts for the remotely-piloted, high-altitude vehicle. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third generation of the Perseus design, which began with the Perseus Proof-Of-Concept aircraft. Perseus was initially developed as part of NASA's Small High-Altitude Science Aircraft (SHASA

  2. Automatic Flight Controller With Model Inversion

    Science.gov (United States)

    Meyer, George; Smith, G. Allan

    1992-01-01

    Automatic digital electronic control system based on inverse-model-follower concept being developed for proposed vertical-attitude-takeoff-and-landing airplane. Inverse-model-follower control places inverse mathematical model of dynamics of controlled plant in series with control actuators of controlled plant so response of combination of model and plant to command is unity. System includes feedback to compensate for uncertainties in mathematical model and disturbances imposed from without.

  3. A Comparitive Analysis of the Influence of Weather on the Flight Altitudes of Birds.

    Science.gov (United States)

    Shamoun-Baranes, Judy; van Loon, Emiel; van Gasteren, Hans; van Belle, Jelmer; Bouten, Willem; Buurma, Luit

    2006-01-01

    Birds pose a serious risk to flight safety worldwide. A Bird Avoidance Model (BAM) is being developed in the Netherlands to reduce the risk of bird aircraft collisions. In order to develop a temporally and spatially dynamic model of bird densities, data are needed on the flight-altitude distribution of birds and how this is influenced by weather. This study focuses on the dynamics of flight altitudes of several species of birds during local flights over land in relation to meteorological conditions.We measured flight altitudes of several species in the southeastern Netherlands using tracking radar during spring and summer 2000. Representatives of different flight strategy groups included four species: a soaring species (buzzard ), an obligatory aerial forager (swift Apus apus), a flapping and gliding species (blackheaded gull Larus ridibundus), and a flapping species (starling Sturnus vulgaris).Maximum flight altitudes varied among species, during the day and among days. Weather significantly influenced the flight altitudes of all species studied. Factors such as temperature, relative humidity, atmospheric instability, cloud cover, and sea level pressure were related to flight altitudes. Different combinations of factors explained 40% 70% of the variance in maximum flight altitudes. Weather affected flight strategy groups differently. Compared to flapping species, buzzards and swifts showed stronger variations in maximum daily altitude and f lew higher under conditions reflecting stronger thermal convection. The dynamic vertical distributions of birds are important for risk assessment and mitigation measures in flight safety as well as wind turbine studies.

  4. Flight calls and orientation

    DEFF Research Database (Denmark)

    Larsen, Ole Næsbye; Andersen, Bent Bach; Kropp, Wibke

    2008-01-01

    flight calls was simulated by sequential computer controlled activation of five loudspeakers placed in a linear array perpendicular to the bird's migration course. The bird responded to this stimulation by changing its migratory course in the direction of that of the ‘flying conspecifics' but after about......  In a pilot experiment a European Robin, Erithacus rubecula, expressing migratory restlessness with a stable orientation, was video filmed in the dark with an infrared camera and its directional migratory activity was recorded. The flight overhead of migrating conspecifics uttering nocturnal...... 30 minutes it drifted back to its original migration course. The results suggest that songbirds migrating alone at night can use the flight calls from conspecifics as additional cues for orientation and that they may compare this information with other cues to decide what course to keep....

  5. attitudes of teachers towards

    African Journals Online (AJOL)

    User

    Ethiopia. A limited understanding of the concept disability, negative attitudes towards .... impairment and mental retardation in ... on the attitudes of the people” Taking part ... feelings about inclusion. ... Brahmnorwich(2002) , younger teachers.

  6. X-1A in flight with flight data superimposed

    Science.gov (United States)

    1953-01-01

    This photo of the X-1A includes graphs of the flight data from Maj. Charles E. Yeager's Mach 2.44 flight on December 12, 1953. (This was only a few days short of the 50th anniversary of the Wright brothers' first powered flight.) After reaching Mach 2.44, then the highest speed ever reached by a piloted aircraft, the X-1A tumbled completely out of control. The motions were so violent that Yeager cracked the plastic canopy with his helmet. He finally recovered from a inverted spin and landed on Rogers Dry Lakebed. Among the data shown are Mach number and altitude (the two top graphs). The speed and altitude changes due to the tumble are visible as jagged lines. The third graph from the bottom shows the G-forces on the airplane. During the tumble, these twice reached 8 Gs or 8 times the normal pull of gravity at sea level. (At these G forces, a 200-pound human would, in effect, weigh 1,600 pounds if a scale were placed under him in the direction of the force vector.) Producing these graphs was a slow, difficult process. The raw data from on-board instrumentation recorded on oscillograph film. Human computers then reduced the data and recorded it on data sheets, correcting for such factors as temperature and instrument errors. They used adding machines or slide rules for their calculations, pocket calculators being 20 years in the future. Three second generation Bell Aircraft Corporations X-1s were built, though four were requested. They were the X-1A (48-1384); X-1B (48-1385); X-1C (canceled and never built); X-1D (48-1386). These aircraft were similar to the X-1s, except they were five feet longer, had conventional canopies, and were powered by Reaction Motors, Inc. XLR11-RM-5 rocket engines. The RM-5, like the previous engines, had no throttle and was controlled by igniting one or more of the four thrust chambers at will. The original program outline called for the X-1A and X-1B to be used for dynamic stability and air loads investigations. The X-1D was to be used

  7. ALOFT Flight Test Report

    Science.gov (United States)

    1977-10-01

    wmmmmmmmmmmmm i ifmu.immM\\]i\\ ßinimm^mmmmviwmmiwui »vimtm twfjmmmmmmi c-f—rmSmn NWC TP 5954 ALOFT Flight Test Report by James D. Ross anrJ I.. M...responsible i"- u conducting the ALOFT Flight Test Program and made contributions to this report: J. Basden , R. ".estbrook, L. Thompson, J. Willians...REPORT DOCUMENTATION PAGE READ INSTRUCTIONS BEFORE COMPLETING FORM 7. AUTMORC«; <oss James D./Xo L. M.y&ohnson IZATION NAME AND ADDRESS Naval

  8. Integrated flight path planning system and flight control system for unmanned helicopters.

    Science.gov (United States)

    Jan, Shau Shiun; Lin, Yu Hsiang

    2011-01-01

    This paper focuses on the design of an integrated navigation and guidance system for unmanned helicopters. The integrated navigation system comprises two systems: the Flight Path Planning System (FPPS) and the Flight Control System (FCS). The FPPS finds the shortest flight path by the A-Star (A*) algorithm in an adaptive manner for different flight conditions, and the FPPS can add a forbidden zone to stop the unmanned helicopter from crossing over into dangerous areas. In this paper, the FPPS computation time is reduced by the multi-resolution scheme, and the flight path quality is improved by the path smoothing methods. Meanwhile, the FCS includes the fuzzy inference systems (FISs) based on the fuzzy logic. By using expert knowledge and experience to train the FIS, the controller can operate the unmanned helicopter without dynamic models. The integrated system of the FPPS and the FCS is aimed at providing navigation and guidance to the mission destination and it is implemented by coupling the flight simulation software, X-Plane, and the computing software, MATLAB. Simulations are performed and shown in real time three-dimensional animations. Finally, the integrated system is demonstrated to work successfully in controlling the unmanned helicopter to operate in various terrains of a digital elevation model (DEM).

  9. Integrated Flight Path Planning System and Flight Control System for Unmanned Helicopters

    Science.gov (United States)

    Jan, Shau Shiun; Lin, Yu Hsiang

    2011-01-01

    This paper focuses on the design of an integrated navigation and guidance system for unmanned helicopters. The integrated navigation system comprises two systems: the Flight Path Planning System (FPPS) and the Flight Control System (FCS). The FPPS finds the shortest flight path by the A-Star (A*) algorithm in an adaptive manner for different flight conditions, and the FPPS can add a forbidden zone to stop the unmanned helicopter from crossing over into dangerous areas. In this paper, the FPPS computation time is reduced by the multi-resolution scheme, and the flight path quality is improved by the path smoothing methods. Meanwhile, the FCS includes the fuzzy inference systems (FISs) based on the fuzzy logic. By using expert knowledge and experience to train the FIS, the controller can operate the unmanned helicopter without dynamic models. The integrated system of the FPPS and the FCS is aimed at providing navigation and guidance to the mission destination and it is implemented by coupling the flight simulation software, X-Plane, and the computing software, MATLAB. Simulations are performed and shown in real time three-dimensional animations. Finally, the integrated system is demonstrated to work successfully in controlling the unmanned helicopter to operate in various terrains of a digital elevation model (DEM). PMID:22164029

  10. Range Flight Safety Requirements

    Science.gov (United States)

    Loftin, Charles E.; Hudson, Sandra M.

    2018-01-01

    The purpose of this NASA Technical Standard is to provide the technical requirements for the NPR 8715.5, Range Flight Safety Program, in regards to protection of the public, the NASA workforce, and property as it pertains to risk analysis, Flight Safety Systems (FSS), and range flight operations. This standard is approved for use by NASA Headquarters and NASA Centers, including Component Facilities and Technical and Service Support Centers, and may be cited in contract, program, and other Agency documents as a technical requirement. This standard may also apply to the Jet Propulsion Laboratory or to other contractors, grant recipients, or parties to agreements to the extent specified or referenced in their contracts, grants, or agreements, when these organizations conduct or participate in missions that involve range flight operations as defined by NPR 8715.5.1.2.2 In this standard, all mandatory actions (i.e., requirements) are denoted by statements containing the term “shall.”1.3 TailoringTailoring of this standard for application to a specific program or project shall be formally documented as part of program or project requirements and approved by the responsible Technical Authority in accordance with NPR 8715.3, NASA General Safety Program Requirements.

  11. Weather and Flight Testing

    Science.gov (United States)

    Wiley, Scott

    2007-01-01

    This viewgraph document reviews some of the weather hazards involved with flight testing. Some of the hazards reviewed are: turbulence, icing, thunderstorms and winds and windshear. Maps, pictures, satellite pictures of the meteorological phenomena and graphs are included. Also included are pictures of damaged aircraft.

  12. Pegasus hypersonic flight research

    Science.gov (United States)

    Curry, Robert E.; Meyer, Robert R., Jr.; Budd, Gerald D.

    1992-01-01

    Hypersonic aeronautics research using the Pegasus air-launched space booster is described. Two areas are discussed in the paper: previously obtained results from Pegasus flights 1 and 2, and plans for future programs. Proposed future research includes boundary-layer transition studies on the airplane-like first stage and also use of the complete Pegasus launch system to boost a research vehicle to hypersonic speeds. Pegasus flight 1 and 2 measurements were used to evaluate the results of several analytical aerodynamic design tools applied during the development of the vehicle as well as to develop hypersonic flight-test techniques. These data indicated that the aerodynamic design approach for Pegasus was adequate and showed that acceptable margins were available. Additionally, the correlations provide insight into the capabilities of these analytical tools for more complex vehicles in which design margins may be more stringent. Near-term plans to conduct hypersonic boundary-layer transition studies are discussed. These plans involve the use of a smooth metallic glove at about the mid-span of the wing. Longer-term opportunities are proposed which identify advantages of the Pegasus launch system to boost large-scale research vehicles to the real-gas hypersonic flight regime.

  13. Flight telerobotic servicer legacy

    Science.gov (United States)

    Shattuck, Paul L.; Lowrie, James W.

    1992-11-01

    The Flight Telerobotic Servicer (FTS) was developed to enhance and provide a safe alternative to human presence in space. The first step for this system was a precursor development test flight (DTF-1) on the Space Shuttle. DTF-1 was to be a pathfinder for manned flight safety of robotic systems. The broad objectives of this mission were three-fold: flight validation of telerobotic manipulator (design, control algorithms, man/machine interfaces, safety); demonstration of dexterous manipulator capabilities on specific building block tasks; and correlation of manipulator performance in space with ground predictions. The DTF-1 system is comprised of a payload bay element (7-DOF manipulator with controllers, end-of-arm gripper and camera, telerobot body with head cameras and electronics module, task panel, and MPESS truss) and an aft flight deck element (force-reflecting hand controller, crew restraint, command and display panel and monitors). The approach used to develop the DTF-1 hardware, software and operations involved flight qualification of components from commercial, military, space, and R controller, end-of-arm tooling, force/torque transducer) and the development of the telerobotic system for space applications. The system is capable of teleoperation and autonomous control (advances state of the art); reliable (two-fault tolerance); and safe (man-rated). Benefits from the development flight included space validation of critical telerobotic technologies and resolution of significant safety issues relating to telerobotic operations in the Shuttle bay or in the vicinity of other space assets. This paper discusses the lessons learned and technology evolution that stemmed from developing and integrating a dexterous robot into a manned system, the Space Shuttle. Particular emphasis is placed on the safety and reliability requirements for a man-rated system as these are the critical factors which drive the overall system architecture. Other topics focused on include

  14. Free roaming dogs and the communities' knowledge, attitude and ...

    African Journals Online (AJOL)

    Free roaming dogs and the communities' knowledge, attitude and practices of ... Understanding the dynamics of free roaming dog populations is, thus, a step to ... and other related costs), public health impact and social value of the disease.

  15. Stroke in Commercial Flights.

    Science.gov (United States)

    Álvarez-Velasco, Rodrigo; Masjuan, Jaime; DeFelipe, Alicia; Corral, Iñigo; Estévez-Fraga, Carlos; Crespo, Leticia; Alonso-Cánovas, Araceli

    2016-04-01

    Stroke on board aircraft has been reported in retrospective case series, mainly focusing on economy class stroke syndrome. Data on the actual incidence, pathogenesis, and prognosis of stroke in commercial flights are lacking. A prospective registry was designed to include all consecutive patients referred from an international airport (40 million passengers a year) to our hospital with a diagnosis of ischemic stroke or transient ischemic attack and onset of symptoms during a flight or immediately after landing. Forty-four patients (32 ischemic strokes and 12 transient ischemic attacks) were included over a 76-month period (January 2008 to April 2014). The estimated incidence of stroke was 1 stroke in 35 000 flights. Pathogeneses of stroke or transient ischemic attack were atherothrombotic in 16 (36%), economy class stroke syndrome in 8 (18%), cardioembolic in 7 (16%), arterial dissection in 4 (9%), lacunar stroke in 4 (9%), and undetermined in 5 (12%) patients. Carotid stenosis >70% was found in 12 (27%) of the patients. Overall prognosis was good, and thrombolysis was applied in 44% of the cases. The most common reason for not treating patients who had experienced stroke onset midflight was the delay in reaching the hospital. Only 1 patient with symptom onset during the flight prompted a flight diversion. We found a low incidence of stroke in the setting of air travel. Economy class stroke syndrome and arterial dissection were well represented in our sample. However, the main pathogenesis was atherothrombosis with a high proportion of patients with high carotid stenosis. © 2016 American Heart Association, Inc.

  16. Wind and Wake Sensing with UAV Formation Flight: System Development and Flight Testing

    Science.gov (United States)

    Larrabee, Trenton Jameson

    Wind turbulence including atmospheric turbulence and wake turbulence have been widely investigated; however, only recently it become possible to use Unmanned Aerial Vehicles (UAVs) as a validation tool for research in this area. Wind can be a major contributing factor of adverse weather for aircraft. More importantly, it is an even greater risk towards UAVs because of their small size and weight. Being able to estimate wind fields and gusts can potentially provide substantial benefits for both unmanned and manned aviation. Possible applications include gust suppression for improving handling qualities, a better warning system for high wind encounters, and enhanced control for small UAVs during flight. On the other hand, the existence of wind can be advantageous since it can lead to fuel savings and longer duration flights through dynamic soaring or thermal soaring. Wakes are an effect of the lift distribution across an aircraft's wing or tail. Wakes can cause substantial disturbances when multiple aircraft are moving through the same airspace. In fact, the perils from an aircraft flying through the wake of another aircraft is a leading cause of the delay between takeoff times at airports. Similar to wind, though, wakes can be useful for energy harvesting and increasing an aircraft's endurance when flying in formation which can be a great advantage to UAVs because they are often limited in flight time due to small payload capacity. Formation flight can most often be seen in manned aircraft but can be adopted for use with unmanned systems. Autonomous flight is needed for flying in the "sweet spot" of the generated wakes for energy harvesting as well as for thermal soaring during long duration flights. For the research presented here formation flight was implemented for the study of wake sensing and gust alleviation. The major contributions of this research are in the areas of a novel technique to estimate wind using an Unscented Kalman filter and experimental wake

  17. Awareness of Implicit Attitudes

    Science.gov (United States)

    Hahn, Adam; Judd, Charles M.; Hirsh, Holen K.; Blair, Irene V.

    2013-01-01

    Research on implicit attitudes has raised questions about how well people know their own attitudes. Most research on this question has focused on the correspondence between measures of implicit attitudes and measures of explicit attitudes, with low correspondence interpreted as showing that people have little awareness of their implicit attitudes. We took a different approach and directly asked participants to predict their results on upcoming IAT measures of implicit attitudes toward five different social groups. We found that participants were surprisingly accurate in their predictions. Across four studies, predictions were accurate regardless of whether implicit attitudes were described as true attitudes or culturally learned associations (Studies 1 and 2), regardless of whether predictions were made as specific response patterns (Study 1) or as conceptual responses (Studies 2–4), and regardless of how much experience or explanation participants received before making their predictions (Study 4). Study 3 further suggested that participants’ predictions reflected unique insight into their own implicit responses, beyond intuitions about how people in general might respond. Prediction accuracy occurred despite generally low correspondence between implicit and explicit measures of attitudes, as found in prior research. All together, the research findings cast doubt on the belief that attitudes or evaluations measured by the IAT necessarily reflect unconscious attitudes. PMID:24294868

  18. New experimental approaches to the biology of flight control systems.

    Science.gov (United States)

    Taylor, Graham K; Bacic, Marko; Bomphrey, Richard J; Carruthers, Anna C; Gillies, James; Walker, Simon M; Thomas, Adrian L R

    2008-01-01

    Here we consider how new experimental approaches in biomechanics can be used to attain a systems-level understanding of the dynamics of animal flight control. Our aim in this paper is not to provide detailed results and analysis, but rather to tackle several conceptual and methodological issues that have stood in the way of experimentalists in achieving this goal, and to offer tools for overcoming these. We begin by discussing the interplay between analytical and empirical methods, emphasizing that the structure of the models we use to analyse flight control dictates the empirical measurements we must make in order to parameterize them. We then provide a conceptual overview of tethered-flight paradigms, comparing classical ;open-loop' and ;closed-loop' setups, and describe a flight simulator that we have recently developed for making flight dynamics measurements on tethered insects. Next, we provide a conceptual overview of free-flight paradigms, focusing on the need to use system identification techniques in order to analyse the data they provide, and describe two new techniques that we have developed for making flight dynamics measurements on freely flying birds. First, we describe a technique for obtaining inertial measurements of the orientation, angular velocity and acceleration of a steppe eagle Aquila nipalensis in wide-ranging free flight, together with synchronized measurements of wing and tail kinematics using onboard instrumentation and video cameras. Second, we describe a photogrammetric method to measure the 3D wing kinematics of the eagle during take-off and landing. In each case, we provide demonstration data to illustrate the kinds of information available from each method. We conclude by discussing the prospects for systems-level analyses of flight control using these techniques and others like them.

  19. Attitude Control and Orbital Dynamics Challenges of Removing the First 3-Axis Stabilized Tracking and Data Relay Satellite from the Geosynchronous ARC

    Science.gov (United States)

    Benet, Charles A.; Hofman, Henry; Williams, Thomas E.; Olney, Dave; Zaleski, Ronald

    2011-01-01

    Launched on April 4, 1983 onboard STS 6 (Space Shuttle Challenger), the First Tracking and Data Relay Satellite (TDRS 1) was retired above the Geosynchronous Orbit (GEO) on June 27, 2010 after having provided real-time communications with a variety of low-orbiting spacecraft over a 26-year period. To meet NASA requirements limiting orbital debris 1, a team of experts was assembled to conduct an End-Of-Mission (EOM) procedure to raise the satellite 350 km above the GEO orbit. Following the orbit raising via conventional station change maneuvers, the team was confronted with having to deplete the remaining propellant and passivate all energy storage or generation sources. To accomplish these tasks within the time window, communications (telemetry and control links), electrical power, propulsion, and thermal constraints, a spacecraft originally designed as a three-axis stabilized satellite was turned into a spinner. This paper (a companion paper to Innovative Approach Enabled the Retirement of TDRS 1, paper # 1699, IEEE 2011 Aerospace Conference, March 5-12, 2011 sup 2) focuses on the challenges of maintaining an acceptable spinning dynamics, while repetitively firing thrusters. Also addressed are the effects of thruster firings on the orbit characteristics and how they were mitigated by a careful scheduling of the fuel depletion operations. Periodic thruster firings for spin rate adjustment, nutation damping, and precession of the momentum vector were also required in order to maintain effective communications with the satellite. All operations were thoroughly rehearsed and supported by simulations thus lending a high level of confidence in meeting the NASA EOM goals.

  20. Testing Microgravity Flight Hardware Concepts on the NASA KC-135

    Science.gov (United States)

    Motil, Susan M.; Harrivel, Angela R.; Zimmerli, Gregory A.

    2001-01-01

    This paper provides an overview of utilizing the NASA KC-135 Reduced Gravity Aircraft for the Foam Optics and Mechanics (FOAM) microgravity flight project. The FOAM science requirements are summarized, and the KC-135 test-rig used to test hardware concepts designed to meet the requirements are described. Preliminary results regarding foam dispensing, foam/surface slip tests, and dynamic light scattering data are discussed in support of the flight hardware development for the FOAM experiment.

  1. Engineering parameter determination from the radio astronomy explorer /RAE I/ satellite attitude data

    Science.gov (United States)

    Lawlor, E. A.; Davis, R. M.; Blanchard, D. L.

    1974-01-01

    An RAE-I satellite description is given, taking into account a dynamics experiment and the attitude sensing system. A computer program for analyzing flexible spacecraft attitude motions is considered, giving attention to the geometry of rod deformation. The characteristics of observed attitude data are discussed along with an analysis of the main boom root angle, the bending rigidity, and the damper plane angle.

  2. Analysis of rocket flight stability based on optical image measurement

    Science.gov (United States)

    Cui, Shuhua; Liu, Junhu; Shen, Si; Wang, Min; Liu, Jun

    2018-02-01

    Based on the abundant optical image measurement data from the optical measurement information, this paper puts forward the method of evaluating the rocket flight stability performance by using the measurement data of the characteristics of the carrier rocket in imaging. On the basis of the method of measuring the characteristics of the carrier rocket, the attitude parameters of the rocket body in the coordinate system are calculated by using the measurements data of multiple high-speed television sets, and then the parameters are transferred to the rocket body attack angle and it is assessed whether the rocket has a good flight stability flying with a small attack angle. The measurement method and the mathematical algorithm steps through the data processing test, where you can intuitively observe the rocket flight stability state, and also can visually identify the guidance system or failure analysis.

  3. Sensor fault detection and recovery in satellite attitude control

    Science.gov (United States)

    Nasrolahi, Seiied Saeed; Abdollahi, Farzaneh

    2018-04-01

    This paper proposes an integrated sensor fault detection and recovery for the satellite attitude control system. By introducing a nonlinear observer, the healthy sensor measurements are provided. Considering attitude dynamics and kinematic, a novel observer is developed to detect the fault in angular rate as well as attitude sensors individually or simultaneously. There is no limit on type and configuration of attitude sensors. By designing a state feedback based control signal and Lyapunov stability criterion, the uniformly ultimately boundedness of tracking errors in the presence of sensor faults is guaranteed. Finally, simulation results are presented to illustrate the performance of the integrated scheme.

  4. Retrieving Balloon Data in Flight

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's Ultra Long Duration Balloon (ULDB) program will soon make flights lasting up to 100 days. Some flights may generate high data rates and retrieving this data...

  5. 14 CFR Appendix F to Part 135 - Airplane Flight Recorder Specification

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airplane Flight Recorder Specification F.... F Appendix F to Part 135—Airplane Flight Recorder Specification The recorded values must meet the....125 0.004g 6. Pitch Attitude ±75% ±2° 1 or 0.25 for airplanes operated under § 135.152(j) 0.5° A...

  6. Bisphosphonate ISS Flight Experiment

    Science.gov (United States)

    LeBlanc, Adrian; Matsumoto, Toshio; Jones, Jeffrey; Shapiro, Jay; Lang, Thomas; Shackleford, Linda; Smith, Scott M.; Evans, Harlan; Spector, Elizabeth; Ploutz-Snyder, Robert; hide

    2014-01-01

    The bisphosphonate study is a collaborative effort between the NASA and JAXA space agencies to investigate the potential for antiresorptive drugs to mitigate bone changes associated with long-duration spaceflight. Elevated bone resorption is a hallmark of human spaceflight and bed rest (common zero-G analog). We tested whether an antiresorptive drug in combination with in-flight exercise would ameliorate bone loss and hypercalcuria during longduration spaceflight. Measurements include DXA, QCT, pQCT, and urine and blood biomarkers. We have completed analysis of 7 crewmembers treated with alendronate during flight and the immediate postflight (R+week) data collection in 5 of 10 controls without treatment. Both groups used the advanced resistive exercise device (ARED) during their missions. We previously reported the pre/postflight results of crew taking alendronate during flight (Osteoporosis Int. 24:2105-2114, 2013). The purpose of this report is to present the 12-month follow-up data in the treated astronauts and to compare these results with preliminary data from untreated crewmembers exercising with ARED (ARED control) or without ARED (Pre-ARED control). Results: the table presents DXA and QCT BMD expressed as percentage change from preflight in the control astronauts (18 Pre-ARED and the current 5 ARED-1-year data not yet available) and the 7 treated subjects. As shown previously the combination of exercise plus antiresorptive is effective in preventing bone loss during flight. Bone measures for treated subjects, 1 year after return from space remain at or near baseline values. Except in one region, the treated group maintained or gained bone 1 year after flight. Biomarker data are not currently available for either control group and therefore not presented. However, data from other studies with or without ARED show elevated bone resorption and urinary Ca excretion while bisphosphonate treated subjects show decreases during flight. Comparing the two control

  7. Adaptive Jacobian Fuzzy Attitude Control for Flexible Spacecraft Combined Attitude and Sun Tracking System

    Science.gov (United States)

    Chak, Yew-Chung; Varatharajoo, Renuganth

    2016-07-01

    Many spacecraft attitude control systems today use reaction wheels to deliver precise torques to achieve three-axis attitude stabilization. However, irrecoverable mechanical failure of reaction wheels could potentially lead to mission interruption or total loss. The electrically-powered Solar Array Drive Assemblies (SADA) are usually installed in the pitch axis which rotate the solar arrays to track the Sun, can produce torques to compensate for the pitch-axis wheel failure. In addition, the attitude control of a flexible spacecraft poses a difficult problem. These difficulties include the strong nonlinear coupled dynamics between the rigid hub and flexible solar arrays, and the imprecisely known system parameters, such as inertia matrix, damping ratios, and flexible mode frequencies. In order to overcome these drawbacks, the adaptive Jacobian tracking fuzzy control is proposed for the combined attitude and sun-tracking control problem of a flexible spacecraft during attitude maneuvers in this work. For the adaptation of kinematic and dynamic uncertainties, the proposed scheme uses an adaptive sliding vector based on estimated attitude velocity via approximate Jacobian matrix. The unknown nonlinearities are approximated by deriving the fuzzy models with a set of linguistic If-Then rules using the idea of sector nonlinearity and local approximation in fuzzy partition spaces. The uncertain parameters of the estimated nonlinearities and the Jacobian matrix are being adjusted online by an adaptive law to realize feedback control. The attitude of the spacecraft can be directly controlled with the Jacobian feedback control when the attitude pointing trajectory is designed with respect to the spacecraft coordinate frame itself. A significant feature of this work is that the proposed adaptive Jacobian tracking scheme will result in not only the convergence of angular position and angular velocity tracking errors, but also the convergence of estimated angular velocity to

  8. GRODY - GAMMA RAY OBSERVATORY DYNAMICS SIMULATOR IN ADA

    Science.gov (United States)

    Stark, M.

    1994-01-01

    Analysts use a dynamics simulator to test the attitude control system algorithms used by a satellite. The simulator must simulate the hardware, dynamics, and environment of the particular spacecraft and provide user services which enable the analyst to conduct experiments. Researchers at Goddard's Flight Dynamics Division developed GRODY alongside GROSS (GSC-13147), a FORTRAN simulator which performs the same functions, in a case study to assess the feasibility and effectiveness of the Ada programming language for flight dynamics software development. They used popular object-oriented design techniques to link the simulator's design with its function. GRODY is designed for analysts familiar with spacecraft attitude analysis. The program supports maneuver planning as well as analytical testing and evaluation of the attitude determination and control system used on board the Gamma Ray Observatory (GRO) satellite. GRODY simulates the GRO on-board computer and Control Processor Electronics. The analyst/user sets up and controls the simulation. GRODY allows the analyst to check and update parameter values and ground commands, obtain simulation status displays, interrupt the simulation, analyze previous runs, and obtain printed output of simulation runs. The video terminal screen display allows visibility of command sequences, full-screen display and modification of parameters using input fields, and verification of all input data. Data input available for modification includes alignment and performance parameters for all attitude hardware, simulation control parameters which determine simulation scheduling and simulator output, initial conditions, and on-board computer commands. GRODY generates eight types of output: simulation results data set, analysis report, parameter report, simulation report, status display, plots, diagnostic output (which helps the user trace any problems that have occurred during a simulation), and a permanent log of all runs and errors. The

  9. Atmospheric radiation flight dose rates

    Science.gov (United States)

    Tobiska, W. K.

    2015-12-01

    Space weather's effects upon the near-Earth environment are due to dynamic changes in the energy transfer processes from the Sun's photons, particles, and fields. Of the domains that are affected by space weather, the coupling between the solar and galactic high-energy particles, the magnetosphere, and atmospheric regions can significantly affect humans and our technology as a result of radiation exposure. Space Environment Technologies (SET) has been conducting space weather observations of the atmospheric radiation environment at aviation altitudes that will eventually be transitioned into air traffic management operations. The Automated Radiation Measurements for Aerospace Safety (ARMAS) system and Upper-atmospheric Space and Earth Weather eXperiment (USEWX) both are providing dose rate measurements. Both activities are under the ARMAS goal of providing the "weather" of the radiation environment to improve aircraft crew and passenger safety. Over 5-dozen ARMAS and USEWX flights have successfully demonstrated the operation of a micro dosimeter on commercial aviation altitude aircraft that captures the real-time radiation environment resulting from Galactic Cosmic Rays and Solar Energetic Particles. The real-time radiation exposure is computed as an effective dose rate (body-averaged over the radiative-sensitive organs and tissues in units of microsieverts per hour); total ionizing dose is captured on the aircraft, downlinked in real-time, processed on the ground into effective dose rates, compared with NASA's Langley Research Center (LaRC) most recent Nowcast of Atmospheric Ionizing Radiation System (NAIRAS) global radiation climatology model runs, and then made available to end users via the web and smart phone apps. Flight altitudes now exceed 60,000 ft. and extend above commercial aviation altitudes into the stratosphere. In this presentation we describe recent ARMAS and USEWX results.

  10. Flight Crew Health Maintenance

    Science.gov (United States)

    Gullett, C. C.

    1970-01-01

    The health maintenance program for commercial flight crew personnel includes diet, weight control, and exercise to prevent heart disease development and disability grounding. The very high correlation between hypertension and overweight in cardiovascular diseases significantly influences the prognosis for a coronary prone individual and results in a high rejection rate of active military pilots applying for civilian jobs. In addition to physical fitness the major items stressed in pilot selection are: emotional maturity, glucose tolerance, and family health history.

  11. Flight Software Math Library

    Science.gov (United States)

    McComas, David

    2013-01-01

    The flight software (FSW) math library is a collection of reusable math components that provides typical math utilities required by spacecraft flight software. These utilities are intended to increase flight software quality reusability and maintainability by providing a set of consistent, well-documented, and tested math utilities. This library only has dependencies on ANSI C, so it is easily ported. Prior to this library, each mission typically created its own math utilities using ideas/code from previous missions. Part of the reason for this is that math libraries can be written with different strategies in areas like error handling, parameters orders, naming conventions, etc. Changing the utilities for each mission introduces risks and costs. The obvious risks and costs are that the utilities must be coded and revalidated. The hidden risks and costs arise in miscommunication between engineers. These utilities must be understood by both the flight software engineers and other subsystem engineers (primarily guidance navigation and control). The FSW math library is part of a larger goal to produce a library of reusable Guidance Navigation and Control (GN&C) FSW components. A GN&C FSW library cannot be created unless a standardized math basis is created. This library solves the standardization problem by defining a common feature set and establishing policies for the library s design. This allows the libraries to be maintained with the same strategy used in its initial development, which supports a library of reusable GN&C FSW components. The FSW math library is written for an embedded software environment in C. This places restrictions on the language features that can be used by the library. Another advantage of the FSW math library is that it can be used in the FSW as well as other environments like the GN&C analyst s simulators. This helps communication between the teams because they can use the same utilities with the same feature set and syntax.

  12. Radioastron flight operations

    Science.gov (United States)

    Altunin, V. I.; Sukhanov, K. G.; Altunin, K. R.

    1993-01-01

    Radioastron is a space-based very-long-baseline interferometry (VLBI) mission to be operational in the mid-90's. The spacecraft and space radio telescope (SRT) will be designed, manufactured, and launched by the Russians. The United States is constructing a DSN subnet to be used in conjunction with a Russian subnet for Radioastron SRT science data acquisition, phase link, and spacecraft and science payload health monitoring. Command and control will be performed from a Russian tracking facility. In addition to the flight element, the network of ground radio telescopes which will be performing co-observations with the space telescope are essential to the mission. Observatories in 39 locations around the world are expected to participate in the mission. Some aspects of the mission that have helped shaped the flight operations concept are: separate radio channels will be provided for spacecraft operations and for phase link and science data acquisition; 80-90 percent of the spacecraft operational time will be spent in an autonomous mode; and, mission scheduling must take into account not only spacecraft and science payload constraints, but tracking station and ground observatory availability as well. This paper will describe the flight operations system design for translating the Radioastron science program into spacecraft executed events. Planning for in-orbit checkout and contingency response will also be discussed.

  13. Attitude and Trajectory Estimation Using Earth Magnetic Field Data

    Science.gov (United States)

    Deutschmann, Julie; Bar-Itzhack, Itzhack Y.

    1996-01-01

    The magnetometer has long been a reliable, inexpensive sensor used in spacecraft momentum management and attitude estimation. Recent studies show an increased accuracy potential for magnetometer-only attitude estimation systems. Since the Earth's magnetic field is a function of time and position, and since time is known quite precisely, the differences between the computer and measured magnetic field components, as measured by the magnetometers throughout the entire spacecraft orbit, are a function of both the spacecraft trajectory and attitude errors. Therefore, these errors can be used to estimate both trajectory and attitude. Traditionally, satellite attitude and trajectory have been estimated with completely separate system, using different measurement data. Recently, trajectory estimation for low earth orbit satellites was successfully demonstrated in ground software using only magnetometer data. This work proposes a single augmented extended Kalman Filter to simultaneously and autonomously estimate both spacecraft trajectory and attitude with data from a magnetometer and either dynamically determined rates or gyro-measured body rates.

  14. Review on flight simulators (today and tomorrow); Flight simulatior no genjo to kongo

    Energy Technology Data Exchange (ETDEWEB)

    Komura, T. [Mitsubishi Precision Company Limited, Tokyo (Japan)

    2000-04-05

    This paper presents various flight simulators. A flight simulator is classified into that for R and D on aircraft and that for flight training according to its usage. As an example of the former, the general-purpose flight simulation test facility of National Aerospace Laboratory, Science and Technology Agency is in use for development of the STOL experimental aircraft 'Asuka' and simulation experiments for space development. A civil aircraft simulator simulating the interior of a cockpit, operation feeling of piloting devices, flight performance, dynamic characteristics, an engine system and a hydraulic system like a real aircraft is in wide use for training pilots. A fighter simulator for air force is used for training detection of enemy's aircraft by radar, and missile shooting. An antisubmarine patrol aircraft simulator is used for training detection of submarines by sonic detector and magnetic detector, and torpedo air-launching. For both simulators, real simulation of detection sensors or battle environment is required. (NEDO)

  15. Lateral Attitude Change.

    Science.gov (United States)

    Glaser, Tina; Dickel, Nina; Liersch, Benjamin; Rees, Jonas; Süssenbach, Philipp; Bohner, Gerd

    2015-08-01

    The authors propose a framework distinguishing two types of lateral attitude change (LAC): (a) generalization effects, where attitude change toward a focal object transfers to related objects, and (b) displacement effects, where only related attitudes change but the focal attitude does not change. They bring together examples of LAC from various domains of research, outline the conditions and underlying processes of each type of LAC, and develop a theoretical framework that enables researchers to study LAC more systematically in the future. Compared with established theories of attitude change, the LAC framework focuses on lateral instead of focal attitude change and encompasses both generalization and displacement. Novel predictions and designs for studying LAC are presented. © 2014 by the Society for Personality and Social Psychology, Inc.

  16. Attitude Control Performance of IRVE-3

    Science.gov (United States)

    Dillman, Robert A.; Gsell, Valerie T.; Bowden, Ernest L.

    2013-01-01

    The Inflatable Reentry Vehicle Experiment 3 (IRVE-3) launched July 23, 2012, from NASA Wallops Flight Facility and successfully performed its mission, demonstrating both the survivability of a hypersonic inflatable aerodynamic decelerator in the reentry heating environment and the effect of an offset center of gravity on the aeroshell's flight L/D. The reentry vehicle separated from the launch vehicle, released and inflated its aeroshell, reoriented for atmospheric entry, and mechanically shifted its center of gravity before reaching atmospheric interface. Performance data from the entire mission was telemetered to the ground for analysis. This paper discusses the IRVE-3 mission scenario, reentry vehicle design, and as-flown performance of the attitude control system in the different phases of the mission.

  17. Managing Cassini Safe Mode Attitude at Saturn

    Science.gov (United States)

    Burk, Thomas A.

    2010-01-01

    The Cassini spacecraft was launched on October 15, 1997 and arrived at Saturn on June 30, 2004. It has performed detailed observations and remote sensing of Saturn, its rings, and its satellites since that time. In the event safe mode interrupts normal orbital operations, Cassini has flight software fault protection algorithms to detect, isolate, and recover to a thermally safe and commandable attitude and then wait for further instructions from the ground. But the Saturn environment is complex, and safety hazards change depending on where Cassini is in its orbital trajectory around Saturn. Selecting an appropriate safe mode attitude that insures safe operation in the Saturn environment, including keeping the star tracker field of view clear of bright bodies, while maintaining a quiescent, commandable attitude, is a significant challenge. This paper discusses the Cassini safe table management strategy and the key criteria that must be considered, especially during low altitude flybys of Titan, in deciding what spacecraft attitude should be used in the event of safe mode.

  18. F-111C Flight Data Reduction and Analysis Procedures

    Science.gov (United States)

    1990-12-01

    BPHI NO 24 BTHE YES 25 BPSI NO 26 BH YES 27 LVEL NO 28 LBET NO 29 LALP YES 30 LPHI NO 31 LTHE NO 32 LPSI NO 33 LH NO 34 TABLE 2 INPUTS I Ax YES 2 Av NO...03 * 51 IJ Appendix G - A priori Data from Six Degree of Free- dom Flight Dynamic Model The six degree of freedom flight dynamic mathematical model of...Estimated Mathematical mode response - > of aircraft !Gauss- Maximum " Newton --- likelihood 4,computational cost Salgorithm function Maximum

  19. Flight suspension for the relativity gyro

    International Nuclear Information System (INIS)

    Patten, R.A. van

    1983-01-01

    A suspension system for levitation and precision positioning of the niobium coated spherical quartz gyro rotor during orbital flight has been simulated. The system employs multiple controllers and estimators with microprocessor (Z80) controlled range switching. The resulting system handles external accelerations up to 1 g in the highest range yet in the lowest range, below 10 -6 g the sensor noise power spectral density produces only 10 -10 g rms in the rotor. The system is capable of automatic emergency switch up within 100 μsec. Switch down is automatic to expected flight levels of ± 5 x 10 -8 g. Positioning accuracy in all ranges including emergency switch up is ± 5 μin. static, and ± 50 μin. dynamic. The average acceleration during the mission should be 10 -10 g to attain the science data accuracy goal. (Auth.)

  20. Biologically Inspired Micro-Flight Research

    Science.gov (United States)

    Raney, David L.; Waszak, Martin R.

    2003-01-01

    Natural fliers demonstrate a diverse array of flight capabilities, many of which are poorly understood. NASA has established a research project to explore and exploit flight technologies inspired by biological systems. One part of this project focuses on dynamic modeling and control of micro aerial vehicles that incorporate flexible wing structures inspired by natural fliers such as insects, hummingbirds and bats. With a vast number of potential civil and military applications, micro aerial vehicles represent an emerging sector of the aerospace market. This paper describes an ongoing research activity in which mechanization and control concepts for biologically inspired micro aerial vehicles are being explored. Research activities focusing on a flexible fixed- wing micro aerial vehicle design and a flapping-based micro aerial vehicle concept are presented.

  1. Global fast dynamic terminal sliding mode control for a quadrotor UAV.

    Science.gov (United States)

    Xiong, Jing-Jing; Zhang, Guo-Bao

    2017-01-01

    A control method based on global fast dynamic terminal sliding mode control (TSMC) technique is proposed to design the flight controller for performing the finite-time position and attitude tracking control of a small quadrotor UAV. Firstly, the dynamic model of the quadrotor is divided into two subsystems, i.e., a fully actuated subsystem and an underactuated subsystem. Secondly, the dynamic flight controllers of the quadrotor are formulated based on global fast dynamic TSMC, which is able to guarantee that the position and velocity tracking errors of all system state variables converge to zero in finite-time. Moreover, the global fast dynamic TSMC is also able to eliminate the chattering phenomenon caused by the switching control action and realize the high precision performance. In addition, the stabilities of two subsystems are demonstrated by Lyapunov theory, respectively. Lastly, the simulation results are given to illustrate the effectiveness and robustness of the proposed control method in the presence of external disturbances. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  2. Orbit-attitude coupled motion around small bodies: Sun-synchronous orbits with Sun-tracking attitude motion

    Science.gov (United States)

    Kikuchi, Shota; Howell, Kathleen C.; Tsuda, Yuichi; Kawaguchi, Jun'ichiro

    2017-11-01

    The motion of a spacecraft in proximity to a small body is significantly perturbed due to its irregular gravity field and solar radiation pressure. In such a strongly perturbed environment, the coupling effect of the orbital and attitude motions exerts a large influence that cannot be neglected. However, natural orbit-attitude coupled dynamics around small bodies that are stationary in both orbital and attitude motions have yet to be observed. The present study therefore investigates natural coupled motion that involves both a Sun-synchronous orbit and Sun-tracking attitude motion. This orbit-attitude coupled motion enables a spacecraft to maintain its orbital geometry and attitude state with respect to the Sun without requiring active control. Therefore, the proposed method can reduce the use of an orbit and attitude control system. This paper first presents analytical conditions to achieve Sun-synchronous orbits and Sun-tracking attitude motion. These analytical solutions are then numerically propagated based on non-linear coupled orbit-attitude equations of motion. Consequently, the possibility of implementing Sun-synchronous orbits with Sun-tracking attitude motion is demonstrated.

  3. Free-flight experiments in LISA Pathfinder

    International Nuclear Information System (INIS)

    Armano, M; Audley, H; Born, M; Danzmann, K; Diepholz, I; Auger, G; Binetruy, P; Baird, J; Bortoluzzi, D; Brandt, N; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Dolesi, R; Ferroni, V; Cruise, M; Cutler, C; Dunbar, N; Ferraioli, L

    2015-01-01

    The LISA Pathfinder mission will demonstrate the technology of drag-free test masses for use as inertial references in future space-based gravitational wave detectors. To accomplish this, the Pathfinder spacecraft will perform drag-free flight about a test mass while measuring the acceleration of this primary test mass relative to a second reference test mass. Because the reference test mass is contained within the same spacecraft, it is necessary to apply forces on it to maintain its position and attitude relative to the spacecraft. These forces are a potential source of acceleration noise in the LISA Pathfinder system that are not present in the full LISA configuration. While LISA Pathfinder has been designed to meet it's primary mission requirements in the presence of this noise, recent estimates suggest that the on-orbit performance may be limited by this ‘suspension noise’. The drift-mode or free-flight experiments provide an opportunity to mitigate this noise source and further characterize the underlying disturbances that are of interest to the designers of LISA-like instruments. This article provides a high-level overview of these experiments and the methods under development to analyze the resulting data. (paper)

  4. Balancing Training Techniques for Flight Controller Certification

    Science.gov (United States)

    Gosling, Christina

    2011-01-01

    Training of ground control teams has been a difficult task in space operations. There are several intangible skills that must be learned to become the steely eyed men and women of mission control who respond to spacecraft failures that can lead to loss of vehicle or crew if handled improperly. And as difficult as training is, it can also be costly. Every day, month or year an operator is in training, is a day that not only they are being trained without direct benefit to the organization, but potentially an instructor or mentor is also being paid for hours spent assisting them. Therefore, optimization of the training flow is highly desired. Recently the Expedition Division (DI) at Johnson Space Flight Center has recreated their training flows for the purpose of both moving to an operator/specialist/instructor hierarchy and to address past inefficiencies in the training flow. This paper will discuss the types of training DI is utilizing in their new flows, and the balance that has been struck between the ideal learning environments and realistic constraints. Specifically, the past training flow for the ISS Attitude Determination and Control Officer will be presented, including drawbacks that were encountered. Then the new training flow will be discussed and how a new approach utilizes more training methods and teaching techniques. We will look at how DI has integrated classes, workshops, checkouts, module reviews, scenarios, OJT, paper sims, Mini Sims, and finally Integrated Sims to balance the cost and timing of training a new flight controller.

  5. Optimizing the Attitude Control of Small Satellite Constellations for Rapid Response Imaging

    Science.gov (United States)

    Nag, S.; Li, A.

    2016-12-01

    Distributed Space Missions (DSMs) such as formation flight and constellations, are being recognized as important solutions to increase measurement samples over space and time. Given the increasingly accurate attitude control systems emerging in the commercial market, small spacecraft now have the ability to slew and point within few minutes of notice. In spite of hardware development in CubeSats at the payload (e.g. NASA InVEST) and subsystems (e.g. Blue Canyon Technologies), software development for tradespace analysis in constellation design (e.g. Goddard's TAT-C), planning and scheduling development in single spacecraft (e.g. GEO-CAPE) and aerial flight path optimizations for UAVs (e.g. NASA Sensor Web), there is a gap in open-source, open-access software tools for planning and scheduling distributed satellite operations in terms of pointing and observing targets. This paper will demonstrate results from a tool being developed for scheduling pointing operations of narrow field-of-view (FOV) sensors over mission lifetime to maximize metrics such as global coverage and revisit statistics. Past research has shown the need for at least fourteen satellites to cover the Earth globally everyday using a LandSat-like sensor. Increasing the FOV three times reduces the need to four satellites, however adds image distortion and BRDF complexities to the observed reflectance. If narrow FOV sensors on a small satellite constellation were commanded using robust algorithms to slew their sensor dynamically, they would be able to coordinately cover the global landmass much faster without compensating for spatial resolution or BRDF effects. Our algorithm to optimize constellation satellite pointing is based on a dynamic programming approach under the constraints of orbital mechanics and existing attitude control systems for small satellites. As a case study for our algorithm, we minimize the time required to cover the 17000 Landsat images with maximum signal to noise ratio fall

  6. Epistemics and attitudes

    Directory of Open Access Journals (Sweden)

    Pranav Anand

    2013-10-01

    Full Text Available This paper investigates the distribution of epistemic modals in attitude contexts in three Romance languages, as well as their potential interaction with mood selection. We show that epistemics can appear in complements of attitudes of acceptance (Stalnaker 1984, but not desideratives or directives; in addition, emotive doxastics (hope, fear and dubitatives (doubt permit epistemic possibility modals, but not their necessity counterparts. We argue that the embedding differences across attitudes indicate that epistemics are sensitive to the type of attitude an attitude predicate reports. We show that this sensitivity can be derived by adopting two types of proposals from the literature on epistemic modality and on attitude verbs: First, we assume that epistemics do not target knowledge uniformly, but rather quantify over an information state determined by the content of the embedding attitude (Hacquard 2006, 2010, Yalcin 2007. In turn, we adopt a fundamental split in the semantics of attitude verbs between ‘representational’ and ‘non-representational’ attitudes (Bolinger 1968: representational attitudes quantify over an information state (e.g., a set of beliefs for believe, which, we argue, epistemic modals can be anaphoric to. Non-representational attitudes do not quantify over an information state; instead, they combine with their complement via a comparison with contextually-provided alternatives using a logic of preference (cf. Bolinger 1968, Stalnaker 1984, Farkas 1985, Heim 1992, Villalta 2000, 2008. Finally, we argue that emotive doxastics and dubitatives have a hybrid semantics, which combines a representational component (responsible for licensing epistemic possibility modals, and a preference component (responsible for disallowing epistemic necessity modals. http://dx.doi.org/10.3765/sp.6.8 BibTeX info

  7. Rocket Flight Path

    Directory of Open Access Journals (Sweden)

    Jamie Waters

    2014-09-01

    Full Text Available This project uses Newton’s Second Law of Motion, Euler’s method, basic physics, and basic calculus to model the flight path of a rocket. From this, one can find the height and velocity at any point from launch to the maximum altitude, or apogee. This can then be compared to the actual values to see if the method of estimation is a plausible. The rocket used for this project is modeled after Bullistic-1 which was launched by the Society of Aeronautics and Rocketry at the University of South Florida.

  8. Flight Mechanics Project

    Science.gov (United States)

    Steck, Daniel

    2009-01-01

    This report documents the generation of an outbound Earth to Moon transfer preliminary database consisting of four cases calculated twice a day for a 19 year period. The database was desired as the first step in order for NASA to rapidly generate Earth to Moon trajectories for the Constellation Program using the Mission Assessment Post Processor. The completed database was created running a flight trajectory and optimization program, called Copernicus, in batch mode with the use of newly created Matlab functions. The database is accurate and has high data resolution. The techniques and scripts developed to generate the trajectory information will also be directly used in generating a comprehensive database.

  9. Flight to America

    Directory of Open Access Journals (Sweden)

    Güneli Gün

    2011-01-01

    Full Text Available Güneli Gün’s memoir piece truly combines the excitement of the young traveler with the humor of the mature narrator. Born in Izmir, Turkey, she breaks her engagement to a young but conservative Turkish architect and overcomes her father’s concerns to eventually study at Hollins College, Virginia. Addressing topics such as breaking out of a traditional society, being torn between the home country and the imagined new home, and finding comfort in the arts, “Flight to America” compellingly reflects Güneli Gün’s mastery as a storyteller.

  10. New Methodology for Optimal Flight Control using Differential Evolution Algorithms applied on the Cessna Citation X Business Aircraft – Part 2. Validation on Aircraft Research Flight Level D Simulator

    OpenAIRE

    Yamina BOUGHARI; Georges GHAZI; Ruxandra Mihaela BOTEZ; Florian THEEL

    2017-01-01

    In this paper the Cessna Citation X clearance criteria were evaluated for a new Flight Controller. The Flight Control Law were optimized and designed for the Cessna Citation X flight envelope by combining the Deferential Evolution algorithm, the Linear Quadratic Regulator method, and the Proportional Integral controller during a previous research presented in part 1. The optimal controllers were used to reach satisfactory aircraft’s dynamic and safe flight operations with respect to the augme...

  11. Position, Attitude, and Fault-Tolerant Control of Tilting-Rotor Quadcopter

    Science.gov (United States)

    Kumar, Rumit

    The aim of this thesis is to present algorithms for autonomous control of tilt-rotor quadcopter UAV. In particular, this research work describes position, attitude and fault tolerant control in tilt-rotor quadcopter. Quadcopters are one of the most popular and reliable unmanned aerial systems because of the design simplicity, hovering capabilities and minimal operational cost. Numerous applications for quadcopters have been explored all over the world but very little work has been done to explore design enhancements and address the fault-tolerant capabilities of the quadcopters. The tilting rotor quadcopter is a structural advancement of traditional quadcopter and it provides additional actuated controls as the propeller motors are actuated for tilt which can be utilized to improve efficiency of the aerial vehicle during flight. The tilting rotor quadcopter design is accomplished by using an additional servo motor for each rotor that enables the rotor to tilt about the axis of the quadcopter arm. Tilting rotor quadcopter is a more agile version of conventional quadcopter and it is a fully actuated system. The tilt-rotor quadcopter is capable of following complex trajectories with ease. The control strategy in this work is to use the propeller tilts for position and orientation control during autonomous flight of the quadcopter. In conventional quadcopters, two propellers rotate in clockwise direction and other two propellers rotate in counter clockwise direction to cancel out the effective yawing moment of the system. The variation in rotational speeds of these four propellers is utilized for maneuvering. On the other hand, this work incorporates use of varying propeller rotational speeds along with tilting of the propellers for maneuvering during flight. The rotational motion of propellers work in sync with propeller tilts to control the position and orientation of the UAV during the flight. A PD flight controller is developed to achieve various modes of the

  12. Intification and modelling of flight characteristics for self-build shock flyer type UAV

    Science.gov (United States)

    Rashid., Z. A.; Dardin, A. S. F. Syed.; Azid, A. A.; Ahmad, K. A.

    2018-02-01

    The development of an autonomous Unmanned Aerial Vehicle (UAV) requires a fundamentals studies of the UAV's flight characteristic. The aim of this study is to identify and model the flight characteristic of a conventional fixed-wing type UAV. Subsequence to this, the mode of flight of the UAV can be investigated. One technique to identify the characteristic of a UAV is a flight test where it required specific maneuvering to be executed while measuring the attitude sensor. In this study, a simple shock flyer type UAV was used as the aircraft. The result shows that the modeled flight characteristic has a significant relation with actual values but the fitting value is rather small. It is suggested that the future study is conducted with an improvement of the physical UAV, data filtering and better system identification methods.

  13. Pornography and Attitude Change

    Science.gov (United States)

    Wallace, Douglas H.; Wehmer, Gerald

    1971-01-01

    The results indicate that a voluntary three hour exposure to erotic pictures, some of which have been defined as being legally obscene," does not lead to a change in a person's attitudes toward such materials or in attitudes toward their censorship. (Author)

  14. Individual Attitudes Towards Trade

    DEFF Research Database (Denmark)

    Jäkel, Ina Charlotte; Smolka, Marcel

    2013-01-01

    Using the 2007 wave of the Pew Global Attitudes Project, this paper finds statistically significant and economically large Stolper-Samuelson effects in individuals’ preference formation towards trade policy. High-skilled individuals are substantially more pro-trade than low-skilled individuals......-Ohlin model in shaping free trade attitudes, relative to existing literature....

  15. Attitude and position tracking

    CSIR Research Space (South Africa)

    Candy, LP

    2011-01-01

    Full Text Available Several applications require the tracking of attitude and position of a body based on velocity data. It is tempting to use direction cosine matrices (DCM), for example, to track attitude based on angular velocity data, and to integrate the linear...

  16. Attitudes towards documentary soundstracks

    DEFF Research Database (Denmark)

    Have, Iben

    2010-01-01

    . By listening to different voices - primarily from four focus group interviews - the article will discuss attitudes towards musical soundtracks in documentaries, attitudes being negotiated between emotional immersion and critical reflection, with the concept of manipulation as an underlying theme. In the end...

  17. Language Learners' Acculturation Attitudes

    Science.gov (United States)

    Rafieyan, Vahid; Orang, Maryam; Bijami, Maryam; Nejad, Maryam Sharafi; Eng, Lin Siew

    2014-01-01

    Learning a language involves knowledge of both linguistic competence and cultural competence. Optimal development of linguistic competence and cultural competence, however, requires a high level of acculturation attitude toward the target language culture. To this end, the present study explored the acculturation attitudes of 70 Iranian…

  18. 14 CFR Appendix M to Part 121 - Airplane Flight Recorder Specifications

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Airplane Flight Recorder Specifications M... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Pt. 121, App. M Appendix M to Part 121—Airplane... airplanes operated under § 121.344(f) 0.5° A sampling rate of 0.25 is recommended. 7. Roll attitude 2 ±180...

  19. Design and flight testing of a nullable compressor face rake

    Science.gov (United States)

    Holzman, J. K.; Payne, G. A.

    1973-01-01

    A compressor face rake with an internal valve arrangement to permit nulling was designed, constructed, and tested in the laboratory and in flight at the NASA Flight Research Center. When actuated by the pilot in flight, the nullable rake allowed the transducer zero shifts to be determined and then subsequently removed during data reduction. Design details, the fabrication technique, the principle of operation, brief descriptions of associated digital zero-correction programs and the qualification tests, and test results are included. Sample flight data show that the zero shifts were large and unpredictable but could be measured in flight with the rake. The rake functioned reliably and as expected during 25 hours of operation under flight environmental conditions and temperatures from 230 K (-46 F) to greater than 430 K (314 F). The rake was nulled approximately 1000 times. The in-flight zero-shift measurement technique, as well as the rake design, was successful and should be useful in future applications, particularly where accurate measurements of both steady-state and dynamic pressures are required under adverse environmental conditions.

  20. Getting started with Twitter Flight

    CERN Document Server

    Hamshere, Tom

    2013-01-01

    Getting Started with Twitter Flight is written with the intention to educate the readers, helping them learn how to build modular powerful applications with Flight, Twitter's cutting-edge JavaScript framework.This book is for anyone with a foundation in JavaScript who wants to build web applications. Flight is quick and easy to learn, built on technologies you already understand such as the DOM, events, and jQuery.

  1. Real-Time Single-Frequency GPS/MEMS-IMU Attitude Determination of Lightweight UAVs

    Science.gov (United States)

    Eling, Christian; Klingbeil, Lasse; Kuhlmann, Heiner

    2015-01-01

    In this paper, a newly-developed direct georeferencing system for the guidance, navigation and control of lightweight unmanned aerial vehicles (UAVs), having a weight limit of 5 kg and a size limit of 1.5 m, and for UAV-based surveying and remote sensing applications is presented. The system is intended to provide highly accurate positions and attitudes (better than 5 cm and 0.5∘) in real time, using lightweight components. The main focus of this paper is on the attitude determination with the system. This attitude determination is based on an onboard single-frequency GPS baseline, MEMS (micro-electro-mechanical systems) inertial sensor readings, magnetic field observations and a 3D position measurement. All of this information is integrated in a sixteen-state error space Kalman filter. Special attention in the algorithm development is paid to the carrier phase ambiguity resolution of the single-frequency GPS baseline observations. We aim at a reliable and instantaneous ambiguity resolution, since the system is used in urban areas, where frequent losses of the GPS signal lock occur and the GPS measurement conditions are challenging. Flight tests and a comparison to a navigation-grade inertial navigation system illustrate the performance of the developed system in dynamic situations. Evaluations show that the accuracies of the system are 0.05∘ for the roll and the pitch angle and 0.2∘ for the yaw angle. The ambiguities of the single-frequency GPS baseline can be resolved instantaneously in more than 90% of the cases. PMID:26501281

  2. DOA estimation for attitude determination on communication satellites

    Directory of Open Access Journals (Sweden)

    Yang Bin

    2014-06-01

    Full Text Available In order to determine an appropriate attitude of three-axis stabilized communication satellites, this paper describes a novel attitude determination method using direction of arrival (DOA estimation of a ground signal source. It differs from optical measurement, magnetic field measurement, inertial measurement, and global positioning system (GPS attitude determination. The proposed method is characterized by taking the ground signal source as the attitude reference and acquiring attitude information from DOA estimation. Firstly, an attitude measurement equation with DOA estimation is derived in detail. Then, the error of the measurement equation is analyzed. Finally, an attitude determination algorithm is presented using a dynamic model, the attitude measurement equation, and measurement errors. A developing low Earth orbit (LEO satellite which tests mobile communication technology with smart antennas can be stabilized in three axes by corporately using a magnetometer, reaction wheels, and three-axis magnetorquer rods. Based on the communication satellite, simulation results demonstrate the effectiveness of the method. The method could be a backup of attitude determination to prevent a system failure on the satellite. Its precision depends on the number of snapshots and the input signal-to-noise ratio (SNR with DOA estimation.

  3. Flight Results of the NF-15B Intelligent Flight Control System (IFCS) Aircraft with Adaptation to a Longitudinally Destabilized Plant

    Science.gov (United States)

    Bosworth, John T.

    2008-01-01

    Adaptive flight control systems have the potential to be resilient to extreme changes in airplane behavior. Extreme changes could be a result of a system failure or of damage to the airplane. The goal for the adaptive system is to provide an increase in survivability in the event that these extreme changes occur. A direct adaptive neural-network-based flight control system was developed for the National Aeronautics and Space Administration NF-15B Intelligent Flight Control System airplane. The adaptive element was incorporated into a dynamic inversion controller with explicit reference model-following. As a test the system was subjected to an abrupt change in plant stability simulating a destabilizing failure. Flight evaluations were performed with and without neural network adaptation. The results of these flight tests are presented. Comparison with simulation predictions and analysis of the performance of the adaptation system are discussed. The performance of the adaptation system is assessed in terms of its ability to stabilize the vehicle and reestablish good onboard reference model-following. Flight evaluation with the simulated destabilizing failure and adaptation engaged showed improvement in the vehicle stability margins. The convergent properties of this initial system warrant additional improvement since continued maneuvering caused continued adaptation change. Compared to the non-adaptive system the adaptive system provided better closed-loop behavior with improved matching of the onboard reference model. A detailed discussion of the flight results is presented.

  4. Stirling to Flight Initiative

    Science.gov (United States)

    Hibbard, Kenneth E.; Mason, Lee S.; Ndu, Obi; Smith, Clayton; Withrow, James P.

    2016-01-01

    Flight (S2F) initiative with the objective of developing a 100-500 We Stirling generator system. Additionally, a different approach is being devised for this initiative to avoid pitfalls of the past, and apply lessons learned from the recent ASRG experience. Two key aspects of this initiative are a Stirling System Technology Maturation Effort, and a Surrogate Mission Team (SMT) intended to provide clear mission pull and requirements context. The S2F project seeks to lead directly into a DOE flight system development of a new SRG. This paper will detail the proposed S2F initiative, and provide specifics on the key efforts designed to pave a forward path for bringing Stirling technology to flight.

  5. Cibola flight experiment satellite

    Science.gov (United States)

    Davies, P.; Liddle, Doug; Paffett, John; Sweeting, Martin; Curiel, A.; Sun, Wei; Eves, Stuart

    2004-11-01

    In order to achieve an "economy of scale" with respect to payload capacity the major trend in telecommunications satellites is for larger and larger platforms. With these large platforms the level of integration between platform and payload is increasing leading to longer delivery schedules. The typical lifecycle for procurement of these large telecommunications satellites is now 3-6 years depending on the level of non-recurring engineering needed. Surrey Satellite Technology Ltd (SSTL) has designed a low-cost platform aimed at telecommunications and navigation applications. SSTL's Geostationary Minisatellite Platform (GMP) is a new entrant addressing the lower end of the market with payloads up to 250kg requiring less than 1.5 kW power. The British National Space Centre through the MOSAIC Small Satellite Initiative supported the development of GMP. The main design goals for GMP are low-cost for the complete mission including launch and operations and a platform allowing flexible payload accommodation. GMP is specifically designed to allow rapid development and deployment with schedules typically between 1 and 2 years from contract signature to flight readiness. GMP achieves these aims by a modular design where the level of integration between the platform and payload is low. The modular design decomposes the satellite into three major components - the propulsion bay, the avionics bay and the payload module. Both the propulsion and avionics bays are reusable, largely unchanged, and independent of the payload configuration. Such a design means that SSTL or a 3rd party manufacturer can manufacture the payload in parallel to the platform with integration taking place quite late in the schedule. In July 2003 SSTL signed a contract for ESA's first Galileo navigation satellite known as GSTBV2/A. The satellite is based on GMP and ESA plan to launch it into a MEO orbit late in 2005. The second flight of GMP is likely to be in 2006 carrying a geostationary payload

  6. The Cibola flight experiment

    Energy Technology Data Exchange (ETDEWEB)

    Caffrey, Michael Paul [Los Alamos National Laboratory; Nelson, Anthony [Los Alamos National Laboratory; Salazar, Anthony [Los Alamos National Laboratory; Roussel - Dupre, Diane [Los Alamos National Laboratory; Katko, Kim [Los Alamos National Laboratory; Palmer, Joseph [ISE-3; Robinson, Scott [Los Alamos National Laboratory; Wirthlin, Michael [BRIGHAM YOUNG UNIV; Howes, William [BRIGHAM YOUNG UNIV; Richins, Daniel [BRIGHAM YOUNG UNIV

    2009-01-01

    The Cibola Flight Experiment (CFE) is an experimental small satellite carrying a reconfigurable processing instrument developed at the Los Alamos National Laboratory that demonstrates the feasibility of using FPGA-based high-performance computing for sensor processing in the space environment. The CFE satellite was launched on March 8, 2007 in low-earth orbit and has operated extremely well since its deployment. The nine Xilinx Virtex FPGAs used in the payload have been used for several high-throughput sensor processing applications and for single-event upset (SEU) monitoring and mitigation. This paper will describe the CFE system and summarize its operational results. In addition, this paper will describe the results from several SEU detection circuits that were performed on the spacecraft.

  7. Flight plan optimization

    Science.gov (United States)

    Dharmaseelan, Anoop; Adistambha, Keyne D.

    2015-05-01

    Fuel cost accounts for 40 percent of the operating cost of an airline. Fuel cost can be minimized by planning a flight on optimized routes. The routes can be optimized by searching best connections based on the cost function defined by the airline. The most common algorithm that used to optimize route search is Dijkstra's. Dijkstra's algorithm produces a static result and the time taken for the search is relatively long. This paper experiments a new algorithm to optimize route search which combines the principle of simulated annealing and genetic algorithm. The experimental results of route search, presented are shown to be computationally fast and accurate compared with timings from generic algorithm. The new algorithm is optimal for random routing feature that is highly sought by many regional operators.

  8. Space Launch System Ascent Flight Control Design

    Science.gov (United States)

    Orr, Jeb S.; Wall, John H.; VanZwieten, Tannen S.; Hall, Charles E.

    2014-01-01

    A robust and flexible autopilot architecture for NASA's Space Launch System (SLS) family of launch vehicles is presented. The SLS configurations represent a potentially significant increase in complexity and performance capability when compared with other manned launch vehicles. It was recognized early in the program that a new, generalized autopilot design should be formulated to fulfill the needs of this new space launch architecture. The present design concept is intended to leverage existing NASA and industry launch vehicle design experience and maintain the extensibility and modularity necessary to accommodate multiple vehicle configurations while relying on proven and flight-tested control design principles for large boost vehicles. The SLS flight control architecture combines a digital three-axis autopilot with traditional bending filters to support robust active or passive stabilization of the vehicle's bending and sloshing dynamics using optimally blended measurements from multiple rate gyros on the vehicle structure. The algorithm also relies on a pseudo-optimal control allocation scheme to maximize the performance capability of multiple vectored engines while accommodating throttling and engine failure contingencies in real time with negligible impact to stability characteristics. The architecture supports active in-flight disturbance compensation through the use of nonlinear observers driven by acceleration measurements. Envelope expansion and robustness enhancement is obtained through the use of a multiplicative forward gain modulation law based upon a simple model reference adaptive control scheme.

  9. Minisatellite Attitude Guidance Using Reaction Wheels

    Directory of Open Access Journals (Sweden)

    Ion STROE

    2015-06-01

    Full Text Available In a previous paper [2], the active torques needed for the minisatellite attitude guidance from one fixed attitude posture to another fixed attitude posture were determined using an inverse dynamics method. But when considering reaction/momentum wheels, instead of this active torques computation, the purpose is to compute the angular velocities of the three reaction wheels which ensure the minisatellite to rotate from the initial to the final attitude. This paper presents this computation of reaction wheels angular velocities using a similar inverse dynamics method based on inverting Euler’s equations of motion for a rigid body with one fixed point, written in the framework of the x-y-z sequence of rotations parameterization. For the particular case A=B not equal C of an axisymmetric minisatellite, the two computations are compared: the active torques computation versus the computation of reaction wheels angular velocities ̇x , ̇y and ̇z. An interesting observation comes out from this numerical study: if the three reaction wheels are identical (with Iw the moment of inertia of one reaction wheel with respect to its central axis, then the evolutions in time of the products between Iw and the derivatives of the reaction wheels angular velocities, i.e. ̇ , ̇ and ̇ remain the same and do not depend on the moment of inertia Iw.

  10. Adaptive Augmenting Control Flight Characterization Experiment on an F/A-18

    Science.gov (United States)

    VanZwieten, Tannen S.; Gilligan, Eric T.; Wall, John H.; Orr, Jeb S.; Miller, Christopher J.; Hanson, Curtis E.

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) Flight Mechanics and Analysis Division developed an Adaptive Augmenting Control (AAC) algorithm for launch vehicles that improves robustness and performance by adapting an otherwise welltuned classical control algorithm to unexpected environments or variations in vehicle dynamics. This AAC algorithm is currently part of the baseline design for the SLS Flight Control System (FCS), but prior to this series of research flights it was the only component of the autopilot design that had not been flight tested. The Space Launch System (SLS) flight software prototype, including the adaptive component, was recently tested on a piloted aircraft at Dryden Flight Research Center (DFRC) which has the capability to achieve a high level of dynamic similarity to a launch vehicle. Scenarios for the flight test campaign were designed specifically to evaluate the AAC algorithm to ensure that it is able to achieve the expected performance improvements with no adverse impacts in nominal or nearnominal scenarios. Having completed the recent series of flight characterization experiments on DFRC's F/A-18, the AAC algorithm's capability, robustness, and reproducibility, have been successfully demonstrated. Thus, the entire SLS control architecture has been successfully flight tested in a relevant environment. This has increased NASA's confidence that the autopilot design is ready to fly on the SLS Block I vehicle and will exceed the performance of previous architectures.

  11. Walt Disney visited Marshall Space Flight Center (MSFC)

    Science.gov (United States)

    1965-01-01

    Walt Disney toured the West Test Area during his visit to the Marshall Space Flight Center on April 13, 1965. The three in center foreground are Karl Heimburg, Director, Test Division; Dr. von Braun, Director, MSFC; and Walt Disney. The Dynamic Test Stand with the S-1C stage being installed is in the background.

  12. The Flight Control System of the Hovereye (Trademark) VTOL UAV

    Science.gov (United States)

    2007-05-01

    10 RTO-MP-AVT-146 UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED Envelope protection -+ SISO linear Controllers α_dotc Cinematic decoupler ωc αest...T. Ward, “Reentry Vehicle Flight Controls Design Guidelines: Dynamic Inversion”, NASA/TP-2002–210771, March 2002 [14] Pollini, L., Innocenti, M

  13. A comparative analysis of the influence of weather on the flight altitudes of birds

    NARCIS (Netherlands)

    Shamoun-Baranes, J.; van Loon, E.; van Gasteren, H.; van Belle, J.; Bouten, W.; Buurma, L.

    2006-01-01

    Birds pose a serious risk to flight safety worldwide. A Bird Avoidance Model (BAM) is being developed in the Netherlands to reduce the risk of bird-aircraft collisions. In order to develop a temporally and spatially dynamic model of bird densities, data are needed on the flight-altitude distribution

  14. Flight Test Results for the F-16XL With a Digital Flight Control System

    Science.gov (United States)

    Stachowiak, Susan J.; Bosworth, John T.

    2004-01-01

    In the early 1980s, two F-16 airplanes were modified to extend the fuselage length and incorporate a large area delta wing planform. These two airplanes, designated the F-16XL, were designed by the General Dynamics Corporation (now Lockheed Martin Tactical Aircraft Systems) (Fort Worth, Texas) and were prototypes for a derivative fighter evaluation program conducted by the United States Air Force. Although the concept was never put into production, the F-16XL prototypes provided a unique planform for testing concepts in support of future high-speed supersonic transport aircraft. To extend the capabilities of this testbed vehicle the F-16XL ship 1 aircraft was upgraded with a digital flight control system. The added flexibility of a digital flight control system increases the versatility of this airplane as a testbed for aerodynamic research and investigation of advanced technologies. This report presents the handling qualities flight test results covering the envelope expansion of the F-16XL with the digital flight control system.

  15. JACEE long duration balloon flights

    International Nuclear Information System (INIS)

    Burnett, T.; Iwai, J.; Lord, J.J.; Strausz, S.; Wilkes, R.J.; Dake, S.; Oda, H.; Miyamura, O.; Fuki, M.; Jones, W.V.; Gregory, J.; Hayashi, T.; Takahashi, U.; Tominaga, Y.; Wefel, J.P.; Fountain, W.; Derrickson, J.; Parnell, T.A.; Roberts, E.; Tabuki, T.; Watts, J.W.

    1989-01-01

    JACEE balloon-borne emulsion chamber detectors are used to observe the spectra and interactions of cosmic ray protons and nuclei in the energy range 1-100A TeV. Experience with long duration mid-latitude balloon flights and characteristics of the detector system that make it ideal for planned Antarctic balloon flights are discussed. 5 refs., 2 figs

  16. Capital flight and political risk

    NARCIS (Netherlands)

    Lensink, R; Hermes, N; Murinde, [No Value

    This paper provides the first serious attempt to examine the relationship between political risk and capital flight for a large set of developing countries. The outcomes of the analysis show that in most cases political risk variables do have a statistically robust relationship to capital flight

  17. Passengers waste production during flights.

    Science.gov (United States)

    Tofalli, Niki; Loizia, Pantelitsa; Zorpas, Antonis A

    2017-12-20

    We assume that during flights the amount of waste that is produced is limited. However, daily, approximately 8000 commercial airplanes fly above Europe's airspace while at the same time, more than 17,000 commercial flights exist in the entire world. Using primary data from airlines, which use the Larnaca's International Airport (LIA) in Cyprus, we have tried to understand why wastes are produced during a typical flight such as food waste, paper, and plastics, as well as how passengers affect the production of those wastes. The compositional analysis took place on 27 flights of 4 different airlines which used LIA as final destination. The evaluation indicated that the passenger's habits and ethics, and the policy of each airline produced different kinds of waste during the flights and especially food waste (FW). Furthermore, it was observed that the only waste management strategy that exists in place in the airport is the collection and the transportation of all those wastes from aircrafts and from the airport in the central unit for further treatment. Hence, this research indicated extremely difficulties to implement any specific waste minimization, or prevention practice or other sorting methods during the flights due to the limited time of the most flights (less than 3 h), the limited available space within the aircrafts, and the strictly safety roles that exist during the flights.

  18. Measuring Teacher Attitudes toward Mainstreaming.

    Science.gov (United States)

    ERIC Clearinghouse on Tests, Measurement, and Evaluation, Princeton, NJ.

    This brief overview discusses the rationale for measuring teachers' attitudes toward the mainstreaming of handicapped students into regular classrooms, as well as research findings on teacher attitudes. Two attitude tests, Berryman and Berryman's Attitudes Toward Mainstreaming Scale and Hall's Stages of Concern Questionnaire, are also briefly…

  19. Attitude extremity, consensus and diagnosticity

    NARCIS (Netherlands)

    van der Pligt, J.; Ester, P.; van der Linden, J.

    1983-01-01

    Studied the effects of attitude extremity on perceived consensus and willingness to ascribe trait terms to others with either pro- or antinuclear attitudes. 611 Ss rated their attitudes toward nuclear energy on a 5-point scale. Results show that attitude extremity affected consensus estimates. Trait

  20. Aircraft automatic-flight-control system with inversion of the model in the feed-forward path using a Newton-Raphson technique for the inversion

    Science.gov (United States)

    Smith, G. A.; Meyer, G.; Nordstrom, M.

    1986-01-01

    A new automatic flight control system concept suitable for aircraft with highly nonlinear aerodynamic and propulsion characteristics and which must operate over a wide flight envelope was investigated. This exact model follower inverts a complete nonlinear model of the aircraft as part of the feed-forward path. The inversion is accomplished by a Newton-Raphson trim of the model at each digital computer cycle time of 0.05 seconds. The combination of the inverse model and the actual aircraft in the feed-forward path alloys the translational and rotational regulators in the feedback path to be easily designed by linear methods. An explanation of the model inversion procedure is presented. An extensive set of simulation data for essentially the full flight envelope for a vertical attitude takeoff and landing aircraft (VATOL) is presented. These data demonstrate the successful, smooth, and precise control that can be achieved with this concept. The trajectory includes conventional flight from 200 to 900 ft/sec with path accelerations and decelerations, altitude changes of over 6000 ft and 2g and 3g turns. Vertical attitude maneuvering as a tail sitter along all axes is demonstrated. A transition trajectory from 200 ft/sec in conventional flight to stationary hover in the vertical attitude includes satisfactory operation through lift-cure slope reversal as attitude goes from horizontal to vertical at constant altitude. A vertical attitude takeoff from stationary hover to conventional flight is also demonstrated.

  1. Design and simulation of flight control system for man-portable micro reconnaissance quadcopter

    Science.gov (United States)

    Yin, Xinfan; Zhang, Daibing; Fang, Qiang; Shen, Lincheng

    2017-10-01

    The quadcopter has been widely used in the field of aerial photography and environmental detection, because of its advantages of VTOL, simple structure, and easy-control. In the field of urban anti-terrorism or special operations, micro reconnaissance quadcpter has its unique advantages such as all-weather taking off and landing, small noise and so on, and it is very popular with special forces and riot police. This paper aims at the flight control problem of the micro quadcopter, for the purposes of attitude stabilization control and trajectory tracking control of the micro quadcopter, first, the modeling of the micro quadcopter is presented. And using the MATLAB/SIMULINK toolbox to build the flight controller of the micro quadcopter, and then simulation analysis and real flight test are given. The results of the experiment show that the designed PID controller can correct the flight attitude shift effectively and track the planned tracks well, and can achieve the goal of stable and reliable flight of the quadcopter. It can be a useful reference for the flight control system design of future special operations micro UAV.

  2. Attitudes of the selfless

    DEFF Research Database (Denmark)

    Zettler, Ingo; Hilbig, B.E.

    2010-01-01

    Previous research on political orientations, which can be understood as one's left- versus right-wing attitude, has shown that some personality factors yield explanatory power. In the current work, we consider the role of altruism - a personality construct which does not exclusively map onto one...... of the broad personality dimensions typically studied. Altruism was predicted to relate to left-wing attitudes due to an overlap regarding concerns for social equality, and a discrepancy between well-known attributes of right-wingers and altruistic individuals, respectively. Moreover, altruism was expected...... association between altruism and left-wing attitudes, and altruism was found to account for substantial variance in political orientation after controlling for the HEXACO factors of personality. We conclude that altruism is an important construct which deserves attention whenever political attitudes or other...

  3. Attitudes towards Immigration

    DEFF Research Database (Denmark)

    Dinesen, Peter Thisted; Klemmensen, Robert; Nørgaard, Asbjørn Sonne

    2016-01-01

    This article examines if deep-seated psychological differences add to the explanation of attitudes toward immigration. We explore whether the Big Five personality traits matter for immigration attitudes beyond the traditional situational factors of economic and cultural threat and analyze how...... individuals with different personalities react when confronted with the same situational triggers. Using a Danish survey experiment, we show that different personality traits have different effects on opposition toward immigration. We find that Openness has an unconditional effect on attitudes toward...... high on Conscientiousness are more sensitive to the skill level of immigrants. The results imply that personality is important for attitudes toward immigration, and in the conclusion, we further discuss how the observed conditional and unconditional effects of personality make sense theoretically....

  4. Attitudes Towards Immigration

    DEFF Research Database (Denmark)

    Malchow-Møller, Nikolaj; Munch, Jakob Roland; Schroll, Sanne

    In this paper, we re-examine the role of economic self-interest in shaping people’s attitudes towards immigration, using data from the European Social Survey 2002/2003. Compared to the existing literature, there are two main contributions of the present paper. First, we develop a more powerful test...... of the hypothesis that a positive relationship between education and attitudes towards immigration reflects economic self-interest in the labour market. Second, we develop an alternative and more direct test of whether economic self-interest matters for people’s attitudes towards immigration. We find that while...... the "original" relationship between education and attitudes found in the literature is unlikely to reflect economic self-interest, there is considerable evidence of economic self-interest when using the more direct test...

  5. Attitudes Towards Immigration

    DEFF Research Database (Denmark)

    Malchow-Møller, Nikolaj; Roland Munch, Jakob; Schroll, Sanne

    2006-01-01

    In this paper, we re-examine the role of economic self-interest in shaping people's attitudes towards immigration, using data from the European Social Survey 2002/2003. Compared to the existing literature, there are two main contributions of the present paper. First, we develop a more powerful test...... of the hypothesis that a positive relationship between education and attitudes towards immigration reflects economic self-interest in the labour market. Second, we develop an alternativeand more direct test of whether economic self-interest mattersfor people's attitudes towards immigration. We find that whilethe...... "original" relationship between education and attitudes found in the literature is unlikely to reflect economic self-interest, there is considerable evidence of economic self-interest when using the more directtest....

  6. Attitudes towards recreational hunting

    DEFF Research Database (Denmark)

    Gamborg, Christian; Jensen, Frank Søndergaard

    2017-01-01

    a negative attitude to recreational hunting. Older respondents and rural residents had more positive attitudes towards hunting than younger and urban residents. Some of the conditions under which hunting occurs affected attitudes negatively, especially the hunting of farm-reared and released game birds...... to the commercial aspect of hunting and this could result in tighter regulation with further effects on management practices. Management Implications The public opinions and public preferences concerning recreational hunting are complex. However, this study revealed some factors relevant for regulatory...... and managerial development in relation to outdoor recreation: age (younger respondents were least supportive of hunting), urbanisation (living in an urban environment enhanced negative attitudes), compatibility of recreational hunting with other outdoor leisure activities....

  7. Spacecraft Attitude Determination

    DEFF Research Database (Denmark)

    Bak, Thomas

    This thesis describes the development of an attitude determination system for spacecraft based only on magnetic field measurements. The need for such system is motivated by the increased demands for inexpensive, lightweight solutions for small spacecraft. These spacecraft demands full attitude...... determination based on simple, reliable sensors. Meeting these objectives with a single vector magnetometer is difficult and requires temporal fusion of data in order to avoid local observability problems. In order to guaranteed globally nonsingular solutions, quaternions are generally the preferred attitude...... is a detailed study of the influence of approximations in the modeling of the system. The quantitative effects of errors in the process and noise statistics are discussed in detail. The third contribution is the introduction of these methods to the attitude determination on-board the Ørsted satellite...

  8. Acquisition of the Flight Information Using the KSR-3 Agnetometer

    Directory of Open Access Journals (Sweden)

    Sun-Mi Kim

    2003-03-01

    Full Text Available The KSR-3 magnetometers consist of the fluxgate magnetometer (MAG/AIM for acquiring the rocket flight attitude information, and the search-coil magnetometer (MAG/SIM for the observation of the Earth's magnetic fluctuations. The position (latitude, longitude, and height and flight condition (the transformation angle of the rocket is measured after the data based on these two magnetometers are compared with IGRF. The gap in the vector of magnetic field between the position of the launching point and an impact point is taken into account in data reduction. Angular variation of pitch, yaw, and roll can be researched when the data is applied to the coordinate system of the rocket.

  9. Effects of Increased Flight on the Energetics and Life History of the Butterfly Speyeria mormonia.

    Directory of Open Access Journals (Sweden)

    Kristjan Niitepõld

    Full Text Available Movement uses resources that may otherwise be allocated to somatic maintenance or reproduction. How does increased energy expenditure affect resource allocation? Using the butterfly Speyeria mormonia, we tested whether experimentally increased flight affects fecundity, lifespan or flight capacity. We measured body mass (storage, resting metabolic rate and lifespan (repair and maintenance, flight metabolic rate (flight capacity, egg number and composition (reproduction, and food intake across the adult lifespan. The flight treatment did not affect body mass or lifespan. Food intake increased sufficiently to offset the increased energy expenditure. Total egg number did not change, but flown females had higher early-life fecundity and higher egg dry mass than control females. Egg dry mass decreased with age in both treatments. Egg protein, triglyceride or glycogen content did not change with flight or age, but some components tracked egg dry mass. Flight elevated resting metabolic rate, indicating increased maintenance costs. Flight metabolism decreased with age, with a steeper slope for flown females. This may reflect accelerated metabolic senescence from detrimental effects of flight. These effects of a drawdown of nutrients via flight contrast with studies restricting adult nutrient input. There, fecundity was reduced, but flight capacity and lifespan were unchanged. The current study showed that when food resources were abundant, wing-monomorphic butterflies living in a continuous meadow landscape resisted flight-induced stress, exhibiting no evidence of a flight-fecundity or flight-longevity trade-off. Instead, flight changed the dynamics of energy use and reproduction as butterflies adopted a faster lifestyle in early life. High investment in early reproduction may have positive fitness effects in the wild, as long as food is available. Our results help to predict the effect of stressful conditions on the life history of insects living in a

  10. Attitudes towards immigration

    DEFF Research Database (Denmark)

    Malchow-Møller, Nikolaj; Munch, Jakob Roland; Skaksen, Jan Rose

    2008-01-01

    Using the European Social Survey 2002/3, we develop a new test of whether economic self-interest influences people's attitudes towards immigration, exploiting that people have widely different perceptions of the consequences of immigration......Using the European Social Survey 2002/3, we develop a new test of whether economic self-interest influences people's attitudes towards immigration, exploiting that people have widely different perceptions of the consequences of immigration...

  11. Character, attitude and disposition

    OpenAIRE

    Webber, Jonathan

    2015-01-01

    Recent debate over the empirical psychological presuppositions of virtue ethics has focused on reactive behavioural dispositions. But there are many character traits that cannot be understood properly in this way. Such traits are well described by attitude psychology. Moreover, the findings of attitude psychology support virtue ethics in three ways. First, they confirm the role of habituation in the development of character. Further, they show virtue ethics to be compatible with the situation...

  12. Stimulating an Inquiring Attitude

    Directory of Open Access Journals (Sweden)

    Navarrete Sonya Patricia

    2001-08-01

    Full Text Available This article presents the first year experience of teaching Science combined with English in the preschool section with ages between 4 and 6 in the Gimnasio Campestre. A brief theoretical framework is exposed based on inquiring attitudes and theoretical models about this. Then a proposal is presented which was applied to these children; the purpose is to show a new methodology where students will acquire an inquiring attitude through a Science class taught in English.

  13. IVGEN Post Flight Analysis

    Science.gov (United States)

    Mcquillen, John; Brown, Dan; Hussey, Sam; Zoldak, John

    2014-01-01

    The Intravenous Fluid Generation (IVGEN) Experiment was a technology demonstration experiment that purified ISS potable water, mixed it with salt, and transferred it through a sterilizing filter. On-orbit performance was verified as appropriate and two 1.5 l bags of normal saline solution were returned to earth for post-flight testing by a FDA certified laboratory for compliance with United States Pharmacopiea (USP) standards. Salt concentration deviated from required values and an analysis identified probable causes. Current efforts are focused on Total Organic Content (TOC) testing, and shelf life.The Intravenous Fluid Generation (IVGEN) Experiment demonstrated the purification of ISS potable water, the mixing of the purified water with sodium chloride, and sterilization of the solution via membrane filtration. On-orbit performance was monitored where feasible and two 1.5-liter bags of normal saline solution were returned to earth for post-flight testing by a FDA-registered laboratory for compliance with United States Pharmacopeia (USP)standards [1]. Current efforts have been focused on challenge testing with identified [2] impurities (total organic-carbon), and shelf life testing. The challenge testing flowed known concentrations of contaminants through the IVGEN deionizing cartridge and membrane filters to test their effectiveness. One finding was that the filters and DI-resin themselves contribute to the contaminant load during initial startup, suggesting that the first 100 ml of fluid be discarded. Shelf life testing is ongoing and involves periodic testing of stored DI cartridges and membrane filters that are capped and sealed in hermetic packages. The testing is conducted at six month intervals measuring conductivity and endotoxins in the effluent. Currently, the packaging technique has been successfully demonstrated for one year of storage testing. The USP standards specifies that the TOC be conducted at point of generation as opposed to point of

  14. The Space Technology-7 Disturbance Reduction System Precision Control Flight Validation Experiment Control System Design

    Science.gov (United States)

    O'Donnell, James R.; Hsu, Oscar C.; Maghami, Peirman G.; Markley, F. Landis

    2006-01-01

    As originally proposed, the Space Technology-7 Disturbance Reduction System (DRS) project, managed out of the Jet Propulsion Laboratory, was designed to validate technologies required for future missions such as the Laser Interferometer Space Antenna (LISA). The two technologies to be demonstrated by DRS were Gravitational Reference Sensors (GRSs) and Colloidal MicroNewton Thrusters (CMNTs). Control algorithms being designed by the Dynamic Control System (DCS) team at the Goddard Space Flight Center would control the spacecraft so that it flew about a freely-floating GRS test mass, keeping it centered within its housing. For programmatic reasons, the GRSs were descoped from DRS. The primary goals of the new mission are to validate the performance of the CMNTs and to demonstrate precise spacecraft position control. DRS will fly as a part of the European Space Agency (ESA) LISA Pathfinder (LPF) spacecraft along with a similar ESA experiment, the LISA Technology Package (LTP). With no GRS, the DCS attitude and drag-free control systems make use of the sensor being developed by ESA as a part of the LTP. The control system is designed to maintain the spacecraft s position with respect to the test mass, to within 10 nm/the square root of Hz over the DRS science frequency band of 1 to 30 mHz.

  15. Hybrid Adaptive Flight Control with Model Inversion Adaptation

    Science.gov (United States)

    Nguyen, Nhan

    2011-01-01

    This study investigates a hybrid adaptive flight control method as a design possibility for a flight control system that can enable an effective adaptation strategy to deal with off-nominal flight conditions. The hybrid adaptive control blends both direct and indirect adaptive control in a model inversion flight control architecture. The blending of both direct and indirect adaptive control provides a much more flexible and effective adaptive flight control architecture than that with either direct or indirect adaptive control alone. The indirect adaptive control is used to update the model inversion controller by an on-line parameter estimation of uncertain plant dynamics based on two methods. The first parameter estimation method is an indirect adaptive law based on the Lyapunov theory, and the second method is a recursive least-squares indirect adaptive law. The model inversion controller is therefore made to adapt to changes in the plant dynamics due to uncertainty. As a result, the modeling error is reduced that directly leads to a decrease in the tracking error. In conjunction with the indirect adaptive control that updates the model inversion controller, a direct adaptive control is implemented as an augmented command to further reduce any residual tracking error that is not entirely eliminated by the indirect adaptive control.

  16. Development and Evaluation of Fault-Tolerant Flight Control Systems

    Science.gov (United States)

    Song, Yong D.; Gupta, Kajal (Technical Monitor)

    2004-01-01

    The research is concerned with developing a new approach to enhancing fault tolerance of flight control systems. The original motivation for fault-tolerant control comes from the need for safe operation of control elements (e.g. actuators) in the event of hardware failures in high reliability systems. One such example is modem space vehicle subjected to actuator/sensor impairments. A major task in flight control is to revise the control policy to balance impairment detectability and to achieve sufficient robustness. This involves careful selection of types and parameters of the controllers and the impairment detecting filters used. It also involves a decision, upon the identification of some failures, on whether and how a control reconfiguration should take place in order to maintain a certain system performance level. In this project new flight dynamic model under uncertain flight conditions is considered, in which the effects of both ramp and jump faults are reflected. Stabilization algorithms based on neural network and adaptive method are derived. The control algorithms are shown to be effective in dealing with uncertain dynamics due to external disturbances and unpredictable faults. The overall strategy is easy to set up and the computation involved is much less as compared with other strategies. Computer simulation software is developed. A serious of simulation studies have been conducted with varying flight conditions.

  17. A role of abdomen in butterfly's flapping flight

    Science.gov (United States)

    Jayakumar, Jeeva; Senda, Kei; Yokoyama, Naoto

    2017-11-01

    Butterfly's forward flight with periodic flapping motion is longitudinally unstable, and control of the thoracic pitching angle is essential to stabilize the flight. This study aims to comprehend roles which the abdominal motion play in the pitching stability of butterfly's flapping flight by using a two-dimensional model. The control of the thoracic pitching angle by the abdominal motion is an underactuated problem because of the limit on the abdominal angle. The control input of the thorax-abdomen joint torque is obtained by the hierarchical sliding mode control in this study. Numerical simulations reveal that the control by the abdominal motion provides short-term pitching stabilization in the butterfly's flight. Moreover, the control input due to a large thorax-abdomen joint torque can counteract a quite large perturbation, and can return the pitching attitude to the periodic trajectory with a short recovery time. These observations are consistent with biologists' view that living butterflies use their abdomens as rudders. On the other hand, the abdominal control mostly fails in long-term pitching stabilization, because it cannot directly alter the aerodynamic forces. The control for the long-term pitching stabilization will also be discussed.

  18. Radiations and space flight

    International Nuclear Information System (INIS)

    Maalouf, M.; Vogin, G.; Foray, N.; Maalouf; Vogin, G.

    2011-01-01

    A space flight is submitted to 3 main sources of radiation: -) cosmic radiation (4 protons/cm 2 /s and 10000 times less for the heaviest particles), -) solar radiation (10 8 protons/cm 2 /s in the solar wind), -) the Van Allen belt around the earth: the magnetosphere traps particles and at an altitude of 500 km the proton flux can reach 100 protons/cm 2 /s. If we take into account all the spatial missions performed since 1960, we get an average dose of 400 μGray per day with an average dose rate of 0.28 μGray/mn. A significant risk of radiation-induced cancer is expected for missions whose duration is over 250 days.The cataract appears to be the most likely non-cancerous health hazard due to the exposition to comic radiation. Its risk appears to have been under-estimated, particularly for doses over 8 mGray. Some studies on astronauts have shown for some a very strong predisposition for radio-induced cancers: during the reparation phase of DNA breaking due to irradiation, multiple new damages are added by the cells themselves that behave abnormally. (A.C.)

  19. IceBridge Mission Flight Reports

    Data.gov (United States)

    National Aeronautics and Space Administration — The IceBridge Mission Flight Reports data set contains flight reports from NASA Operation IceBridge Greenland, Arctic, Antarctic, and Alaska missions. Flight reports...

  20. On the generalization of attitude accessibility after repeated attitude expression

    Science.gov (United States)

    Spruyt, Adriaan; Fazio, Russell H.; Hermans, Dirk

    2016-01-01

    Abstract The more accessible an attitude is, the stronger is its influence on information processing and behavior. Accessibility can be increased through attitude rehearsal, but it remains unknown whether attitude rehearsal also affects the accessibility of related attitudes. To investigate this hypothesis, participants in an experimental condition repeatedly expressed their attitudes towards exemplars of several semantic categories during an evaluative categorization task. Participants in a control condition performed a non‐evaluative task with the same exemplars and evaluated unrelated attitude objects. After a 30‐minute interval, participants in the experimental condition were faster than controls to evaluate not only the original exemplars but also novel exemplars of the same categories. This finding suggests that the effect of attitude rehearsal on accessibility generalizes to attitudes towards untrained but semantically related attitude objects. © 2016 The Authors. European Journal of Social Psychology published by John Wiley & Sons, Ltd. PMID:28701803

  1. Touchless attitude correction for satellite with constant magnetic moment

    Science.gov (United States)

    Ao, Hou-jun; Yang, Le-ping; Zhu, Yan-wei; Zhang, Yuan-wen; Huang, Huan

    2017-09-01

    Rescue of satellite with attitude fault is of great value. Satellite with improper injection attitude may lose contact with ground as the antenna points to the wrong direction, or encounter energy problems as solar arrays are not facing the sun. Improper uploaded command may set the attitude out of control, exemplified by Japanese Hitomi spacecraft. In engineering practice, traditional physical contact approaches have been applied, yet with a potential risk of collision and a lack of versatility since the mechanical systems are mission-specific. This paper puts forward a touchless attitude correction approach, in which three satellites are considered, one having constant dipole and two having magnetic coils to control attitude of the first. Particular correction configurations are designed and analyzed to maintain the target's orbit during the attitude correction process. A reference coordinate system is introduced to simplify the control process and avoid the singular value problem of Euler angles. Based on the spherical triangle basic relations, the accurate varying geomagnetic field is considered in the attitude dynamic mode. Sliding mode control method is utilized to design the correction law. Finally, numerical simulation is conducted to verify the theoretical derivation. It can be safely concluded that the no-contact attitude correction approach for the satellite with uniaxial constant magnetic moment is feasible and potentially applicable to on-orbit operations.

  2. Nutritional Biochemistry of Space Flight

    Science.gov (United States)

    Smith, Scott M.

    2000-01-01

    Adequate nutrition is critical for maintenance of crew health during and after extended-duration space flight. The impact of weightlessness on human physiology is profound, with effects on many systems related to nutrition, including bone, muscle, hematology, fluid and electrolyte regulation. Additionally, we have much to learn regarding the impact of weightlessness on absorption, mtabolism , and excretion of nutrients, and this will ultimately determine the nutrient requirements for extended-duration space flight. Existing nutritional requirements for extended-duration space flight have been formulated based on limited flight research, and extrapolation from ground-based research. NASA's Nutritional Biochemistry Laboratory is charged with defining the nutritional requirements for space flight. This is accomplished through both operational and research projects. A nutritional status assessment program is included operationally for all International Space Station astronauts. This medical requirement includes biochemical and dietary assessments, and is completed before, during, and after the missions. This program will provide information about crew health and nutritional status, and will also provide assessments of countermeasure efficacy. Ongoing research projects include studies of calcium and bone metabolism, and iron absorption and metabolism. The calcium studies include measurements of endocrine regulation of calcium homeostasis, biochemical marker of bone metabolism, and tracer kinetic studies of calcium movement in the body. These calcium kinetic studies allow for estimation of intestinal absorption, urinary excretion, and perhaps most importantly - deposition and resorption of calcium from bone. The Calcium Kinetics experiment is currently being prepared for flight on the Space Shuttle in 2001, and potentially for subsequent Shuttle and International Space Station missions. The iron study is intended to assess whether iron absorption is down-regulated dUl1ng

  3. Morphing Flight Control Surface for Advanced Flight Performance, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this SBIR project, a new Morphing Flight Control Surface (MFCS) will be developed. The distinction of the research effort is that the SenAnTech team will employ...

  4. Relationships between the Advertising Appeal and Behavioral Intention: The Mediating role of the Attitude towards Advertising Appeal

    OpenAIRE

    Raza Syed Hassan; Abu Bakar Hassan; Mohamad Bahtiar

    2017-01-01

    The link between the advertising appeal, attitude and behavioral intention is dynamic in nature, however, little research has been pursued towards explaining the mediating role of attitude towards the advertising in link of the advertising appeal with the behavioral intention. Researchers have identified the importance of the attitude in the connection of the advertising appeal within the framework of the (TPB) which remains unaddressed in the explicating the mediation of the attitude in rela...

  5. Enclosure enhancement of flight performance

    KAUST Repository

    Ghommem, Mehdi; Garcia, Daniel; Calo, Victor M.

    2014-01-01

    We use a potential flow solver to investigate the aerodynamic aspects of flapping flights in enclosed spaces. The enclosure effects are simulated by the method of images. Our study complements previous aerodynamic analyses which considered only the near-ground flight. The present results show that flying in the proximity of an enclosure affects the aerodynamic performance of flapping wings in terms of lift and thrust generation and power consumption. It leads to higher flight efficiency and more than 5% increase of the generation of lift and thrust.

  6. Enclosure enhancement of flight performance

    Directory of Open Access Journals (Sweden)

    Mehdi Ghommem

    2014-01-01

    Full Text Available We use a potential flow solver to investigate the aerodynamic aspects of flapping flights in enclosed spaces. The enclosure effects are simulated by the method of images. Our study complements previous aerodynamic analyses which considered only the near-ground flight. The present results show that flying in the proximity of an enclosure affects the aerodynamic performance of flapping wings in terms of lift and thrust generation and power consumption. It leads to higher flight efficiency and more than 5% increase of the generation of lift and thrust.

  7. Enclosure enhancement of flight performance

    KAUST Repository

    Ghommem, Mehdi

    2014-08-19

    We use a potential flow solver to investigate the aerodynamic aspects of flapping flights in enclosed spaces. The enclosure effects are simulated by the method of images. Our study complements previous aerodynamic analyses which considered only the near-ground flight. The present results show that flying in the proximity of an enclosure affects the aerodynamic performance of flapping wings in terms of lift and thrust generation and power consumption. It leads to higher flight efficiency and more than 5% increase of the generation of lift and thrust.

  8. Theseus Landing Following Maiden Flight

    Science.gov (United States)

    1996-01-01

    The Theseus prototype research aircraft shows off its high aspect-ratio wing as it comes in for a landing on Rogers Dry Lake after its first test flight from NASA's Dryden Flight Research Center, Edwards, California, on May 24, 1996. The Theseus aircraft, built and operated by Aurora Flight Sciences Corporation, Manassas, Virginia, was a unique aircraft flown at NASA's Dryden Flight Research Center, Edwards, California, under a cooperative agreement between NASA and Aurora. Dryden hosted the Theseus program, providing hangar space and range safety for flight testing. Aurora Flight Sciences was responsible for the actual flight testing, vehicle flight safety, and operation of the aircraft. The Theseus remotely piloted aircraft flew its maiden flight on May 24, 1996, at Dryden. During its sixth flight on November 12, 1996, Theseus experienced an in-flight structural failure that resulted in the loss of the aircraft. As of the beginning of the year 2000, Aurora had not rebuilt the aircraft. Theseus was built for NASA under an innovative, $4.9 million fixed-price contract by Aurora Flight Sciences Corporation and its partners, West Virginia University, Morgantown, West Virginia, and Fairmont State College, Fairmont, West Virginia. The twin-engine, unpiloted vehicle had a 140-foot wingspan, and was constructed largely of composite materials. Powered by two 80-horsepower, turbocharged piston engines that drove twin 9-foot-diameter propellers, Theseus was designed to fly autonomously at high altitudes, with takeoff and landing under the active control of a ground-based pilot in a ground control station 'cockpit.' With the potential ability to carry 700 pounds of science instruments to altitudes above 60,000 feet for durations of greater than 24 hours, Theseus was intended to support research in areas such as stratospheric ozone depletion and the atmospheric effects of future high-speed civil transport aircraft engines. Instruments carried aboard Theseus also would be able

  9. Subscale Flight Testing for Aircraft Loss of Control: Accomplishments and Future Directions

    Science.gov (United States)

    Cox, David E.; Cunningham, Kevin; Jordan, Thomas L.

    2012-01-01

    Subscale flight-testing provides a means to validate both dynamic models and mitigation technologies in the high-risk flight conditions associated with aircraft loss of control. The Airborne Subscale Transport Aircraft Research (AirSTAR) facility was designed to be a flexible and efficient research facility to address this type of flight-testing. Over the last several years (2009-2011) it has been used to perform 58 research flights with an unmanned, remotely-piloted, dynamically-scaled airplane. This paper will present an overview of the facility and its architecture and summarize the experimental data collected. All flights to date have been conducted within visual range of a safety observer. Current plans for the facility include expanding the test volume to altitudes and distances well beyond visual range. The architecture and instrumentation changes associated with this upgrade will also be presented.

  10. Hyper-X Mach 7 Scramjet Design, Ground Test and Flight Results

    Science.gov (United States)

    Ferlemann, Shelly M.; McClinton, Charles R.; Rock, Ken E.; Voland, Randy T.

    2005-01-01

    The successful Mach 7 flight test of the Hyper-X (X-43) research vehicle has provided the major, essential demonstration of the capability of the airframe integrated scramjet engine. This flight was a crucial first step toward realizing the potential for airbreathing hypersonic propulsion for application to space launch vehicles. However, it is not sufficient to have just achieved a successful flight. The more useful knowledge gained from the flight is how well the prediction methods matched the actual test results in order to have confidence that these methods can be applied to the design of other scramjet engines and powered vehicles. The propulsion predictions for the Mach 7 flight test were calculated using the computer code, SRGULL, with input from computational fluid dynamics (CFD) and wind tunnel tests. This paper will discuss the evolution of the Mach 7 Hyper-X engine, ground wind tunnel experiments, propulsion prediction methodology, flight results and validation of design methods.

  11. "Space flight is utter bilge"

    Science.gov (United States)

    Yeomans, Donald

    2004-01-01

    Despite skepticism and ridicule from scientists and the public alike, a small handful of dreamers kept faith in their vision of space flight and planned for the day when humanity would break loose from Earth.

  12. Robust Decentralized Formation Flight Control

    Directory of Open Access Journals (Sweden)

    Zhao Weihua

    2011-01-01

    Full Text Available Motivated by the idea of multiplexed model predictive control (MMPC, this paper introduces a new framework for unmanned aerial vehicles (UAVs formation flight and coordination. Formulated using MMPC approach, the whole centralized formation flight system is considered as a linear periodic system with control inputs of each UAV subsystem as its periodic inputs. Divided into decentralized subsystems, the whole formation flight system is guaranteed stable if proper terminal cost and terminal constraints are added to each decentralized MPC formulation of the UAV subsystem. The decentralized robust MPC formulation for each UAV subsystem with bounded input disturbances and model uncertainties is also presented. Furthermore, an obstacle avoidance control scheme for any shape and size of obstacles, including the nonapriorily known ones, is integrated under the unified MPC framework. The results from simulations demonstrate that the proposed framework can successfully achieve robust collision-free formation flights.

  13. An Application of UAV Attitude Estimation Using a Low-Cost Inertial Navigation System

    Science.gov (United States)

    Eure, Kenneth W.; Quach, Cuong Chi; Vazquez, Sixto L.; Hogge, Edward F.; Hill, Boyd L.

    2013-01-01

    Unmanned Aerial Vehicles (UAV) are playing an increasing role in aviation. Various methods exist for the computation of UAV attitude based on low cost microelectromechanical systems (MEMS) and Global Positioning System (GPS) receivers. There has been a recent increase in UAV autonomy as sensors are becoming more compact and onboard processing power has increased significantly. Correct UAV attitude estimation will play a critical role in navigation and separation assurance as UAVs share airspace with civil air traffic. This paper describes attitude estimation derived by post-processing data from a small low cost Inertial Navigation System (INS) recorded during the flight of a subscale commercial off the shelf (COTS) UAV. Two discrete time attitude estimation schemes are presented here in detail. The first is an adaptation of the Kalman Filter to accommodate nonlinear systems, the Extended Kalman Filter (EKF). The EKF returns quaternion estimates of the UAV attitude based on MEMS gyro, magnetometer, accelerometer, and pitot tube inputs. The second scheme is the complementary filter which is a simpler algorithm that splits the sensor frequency spectrum based on noise characteristics. The necessity to correct both filters for gravity measurement errors during turning maneuvers is demonstrated. It is shown that the proposed algorithms may be used to estimate UAV attitude. The effects of vibration on sensor measurements are discussed. Heuristic tuning comments pertaining to sensor filtering and gain selection to achieve acceptable performance during flight are given. Comparisons of attitude estimation performance are made between the EKF and the complementary filter.

  14. Hybrid adaptive ascent flight control for a flexible launch vehicle

    Science.gov (United States)

    Lefevre, Brian D.

    For the purpose of maintaining dynamic stability and improving guidance command tracking performance under off-nominal flight conditions, a hybrid adaptive control scheme is selected and modified for use as a launch vehicle flight controller. This architecture merges a model reference adaptive approach, which utilizes both direct and indirect adaptive elements, with a classical dynamic inversion controller. This structure is chosen for a number of reasons: the properties of the reference model can be easily adjusted to tune the desired handling qualities of the spacecraft, the indirect adaptive element (which consists of an online parameter identification algorithm) continually refines the estimates of the evolving characteristic parameters utilized in the dynamic inversion, and the direct adaptive element (which consists of a neural network) augments the linear feedback signal to compensate for any nonlinearities in the vehicle dynamics. The combination of these elements enables the control system to retain the nonlinear capabilities of an adaptive network while relying heavily on the linear portion of the feedback signal to dictate the dynamic response under most operating conditions. To begin the analysis, the ascent dynamics of a launch vehicle with a single 1st stage rocket motor (typical of the Ares 1 spacecraft) are characterized. The dynamics are then linearized with assumptions that are appropriate for a launch vehicle, so that the resulting equations may be inverted by the flight controller in order to compute the control signals necessary to generate the desired response from the vehicle. Next, the development of the hybrid adaptive launch vehicle ascent flight control architecture is discussed in detail. Alterations of the generic hybrid adaptive control architecture include the incorporation of a command conversion operation which transforms guidance input from quaternion form (as provided by NASA) to the body-fixed angular rate commands needed by the

  15. Ares I-X Flight Test Validation of Control Design Tools in the Frequency-Domain

    Science.gov (United States)

    Johnson, Matthew; Hannan, Mike; Brandon, Jay; Derry, Stephen

    2011-01-01

    A major motivation of the Ares I-X flight test program was to Design for Data, in order to maximize the usefulness of the data recorded in support of Ares I modeling and validation of design and analysis tools. The Design for Data effort was intended to enable good post-flight characterizations of the flight control system, the vehicle structural dynamics, and also the aerodynamic characteristics of the vehicle. To extract the necessary data from the system during flight, a set of small predetermined Programmed Test Inputs (PTIs) was injected directly into the TVC signal. These PTIs were designed to excite the necessary vehicle dynamics while exhibiting a minimal impact on loads. The method is similar to common approaches in aircraft flight test programs, but with unique launch vehicle challenges due to rapidly changing states, short duration of flight, a tight flight envelope, and an inability to repeat any test. This paper documents the validation effort of the stability analysis tools to the flight data which was performed by comparing the post-flight calculated frequency response of the vehicle to the frequency response calculated by the stability analysis tools used to design and analyze the preflight models during the control design effort. The comparison between flight day frequency response and stability tool analysis for flight of the simulated vehicle shows good agreement and provides a high level of confidence in the stability analysis tools for use in any future program. This is true for both a nominal model as well as for dispersed analysis, which shows that the flight day frequency response is enveloped by the vehicle s preflight uncertainty models.

  16. Attitudes towards poverty

    Directory of Open Access Journals (Sweden)

    Andrzej Derdziuk

    2015-04-01

    Full Text Available Poverty, perceived as a lack of basic consumer goods, gives rise to a whole range of outcomes which affect not only the material dimension of human existence, but also influence social relations and references to spiritual values. Attitudes which could be associated with involuntary and unacceptable poverty include: doubt in the Divine Providence, bitterness, jealousy and envy, blaming others, lack of gratitude and in perceiving good, laziness, lack of initiative, escalating demands, gluttony and greed as well as meanness. However, joy, peace, freedom and solidarity with the poor, as well as work and enterprise, are symptoms of evangelical attitudes of the poor in spirit. Attitudes to poverty point to a wide range of human behaviours towards possessions and in effect, reveal an individual’s sense of value.

  17. Sharing Rare Attitudes Attracts.

    Science.gov (United States)

    Alves, Hans

    2018-04-01

    People like others who share their attitudes. Online dating platforms as well as other social media platforms regularly rely on the social bonding power of their users' shared attitudes. However, little is known about moderating variables. In the present work, I argue that sharing rare compared with sharing common attitudes should evoke stronger interpersonal attraction among people. In five studies, I tested this prediction for the case of shared interests from different domains. I found converging evidence that people's rare compared with their common interests are especially potent to elicit interpersonal attraction. I discuss the current framework's theoretical implications for impression formation and impression management as well as its practical implications for improving online dating services.

  18. Love attitudes and attachment

    Directory of Open Access Journals (Sweden)

    María Elena Brenlla

    2016-02-01

    Full Text Available Love styles described by Lee are Eros (passionate love, Ludus (game-pla- ying love, Storge (friendship love, Mania (possessive, dependent love, Pragma (logical, “shopping list” love and Agape (all-giving, selfless love. Based on those types, Hendrick and Hendrick developed a 42-ítem rating questionnaire with 7 items measuring each love style (Love Attitudes Scale. Beside, inform about frequency in love relationships and attachment style. The purpose of this study was analyze the reliability and factor structure of the Love Attitudes Scale and to investigate the association between love attitudes and the attachment style. The results (N=280 participants indicate adequate internal consistency (alfa = 0,73. The items were intercorrelated and factored. The best solution extracted six factors using varimax rotation and all six factors accounted 41% of the total variance. Secure attachment was related positively to eros. 

  19. Nature and operation of attitudes.

    Science.gov (United States)

    Ajzen, I

    2001-01-01

    This survey of attitude theory and research published between 1996 and 1999 covers the conceptualization of attitude, attitude formation and activation, attitude structure and function, and the attitude-behavior relation. Research regarding the expectancy-value model of attitude is considered, as are the roles of accessible beliefs and affective versus cognitive processes in the formation of attitudes. The survey reviews research on attitude strength and its antecedents and consequences, and covers progress made on the assessment of attitudinal ambivalence and its effects. Also considered is research on automatic attitude activation, attitude functions, and the relation of attitudes to broader values. A large number of studies dealt with the relation between attitudes and behavior. Research revealing additional moderators of this relation is reviewed, as are theory and research on the link between intentions and actions. Most work in this context was devoted to issues raised by the theories of reasoned action and planned behavior. The present review highlights the nature of perceived behavioral control, the relative importance of attitudes and subjective norms, the utility of adding more predictors, and the roles of prior behavior and habit.

  20. Development of Nonlinear Flight Mechanical Model of High Aspect Ratio Light Utility Aircraft

    Science.gov (United States)

    Bahri, S.; Sasongko, R. A.

    2018-04-01

    The implementation of Flight Control Law (FCL) for Aircraft Electronic Flight Control System (EFCS) aims to reduce pilot workload, while can also enhance the control performance during missions that require long endurance flight and high accuracy maneuver. In the development of FCL, a quantitative representation of the aircraft dynamics is needed for describing the aircraft dynamics characteristic and for becoming the basis of the FCL design. Hence, a 6 Degree of Freedom nonlinear model of a light utility aircraft dynamics, also called the nonlinear Flight Mechanical Model (FMM), is constructed. This paper shows the construction of FMM from mathematical formulation, the architecture design of FMM, the trimming process and simulations. The verification of FMM is done by analysis of aircraft behaviour in selected trimmed conditions.

  1. Robustness and Actuator Bandwidth of MRP-Based Sliding Mode Control for Spacecraft Attitude Control Problems

    Science.gov (United States)

    Keum, Jung-Hoon; Ra, Sung-Woong

    2009-12-01

    Nonlinear sliding surface design in variable structure systems for spacecraft attitude control problems is studied. A robustness analysis is performed for regular form of system, and calculation of actuator bandwidth is presented by reviewing sliding surface dynamics. To achieve non-singular attitude description and minimal parameterization, spacecraft attitude control problems are considered based on modified Rodrigues parameters (MRP). It is shown that the derived controller ensures the sliding motion in pre-determined region irrespective of unmodeled effects and disturbances.

  2. On-Ground Attitude and Torque Reconstruction tor the Gaia Mission

    OpenAIRE

    Samaan, Malak; Theil, Stephan

    2008-01-01

    The work presented in this paper concerns the accurate On-Ground Attitude (OGA) reconstruction for the astrometry spacecraft Gaia in the presence of disturbance and control torques acting on the spacecraft. The reconstruction of the expected environmental torques which influence the spacecraft dynamics will be also investigated. The telemetry data from the spacecraft will include the on-board real time attitude which is of order of several arcsec. This raw attitude is the starting point...

  3. Integrated orbit and attitude hardware-in-the-loop simulations for autonomous satellite formation flying

    Science.gov (United States)

    Park, Han-Earl; Park, Sang-Young; Kim, Sung-Woo; Park, Chandeok

    2013-12-01

    Development and experiment of an integrated orbit and attitude hardware-in-the-loop (HIL) simulator for autonomous satellite formation flying are presented. The integrated simulator system consists of an orbit HIL simulator for orbit determination and control, and an attitude HIL simulator for attitude determination and control. The integrated simulator involves four processes (orbit determination, orbit control, attitude determination, and attitude control), which interact with each other in the same way as actual flight processes do. Orbit determination is conducted by a relative navigation algorithm using double-difference GPS measurements based on the extended Kalman filter (EKF). Orbit control is performed by a state-dependent Riccati equation (SDRE) technique that is utilized as a nonlinear controller for the formation control problem. Attitude is determined from an attitude heading reference system (AHRS) sensor, and a proportional-derivative (PD) feedback controller is used to control the attitude HIL simulator using three momentum wheel assemblies. Integrated orbit and attitude simulations are performed for a formation reconfiguration scenario. By performing the four processes adequately, the desired formation reconfiguration from a baseline of 500-1000 m was achieved with meter-level position error and millimeter-level relative position navigation. This HIL simulation demonstrates the performance of the integrated HIL simulator and the feasibility of the applied algorithms in a real-time environment. Furthermore, the integrated HIL simulator system developed in the current study can be used as a ground-based testing environment to reproduce possible actual satellite formation operations.

  4. Dynamic legged locomotion in robots and animals

    Science.gov (United States)

    Raibert, Marc; Playter, Robert; Ringrose, Robert; Bailey, Dave; Leeser, Karl

    1995-01-01

    This report documents our study of active legged systems that balance actively and move dynamically. The purpose of this research is to build a foundation of knowledge that can lead both to the construction of useful legged vehicles and to a better understanding of how animal locomotion works. In this report we provide an update on progress during the past year. Here are the topics covered in this report: (1) Is cockroach locomotion dynamic? To address this question we created three models of cockroaches, each abstracted at a different level. We provided each model with a control system and computer simulation. One set of results suggests that 'Groucho Running,' a type of dynamic walking, seems feasible at cockroach scale. (2) How do bipeds shift weight between the legs? We built a simple planar biped robot specifically to explore this question. It shifts its weight from one curved foot to the other, using a toe-off and toe-on strategy, in conjunction with dynamic tipping. (3) 3D biped gymnastics: The 3D biped robot has done front somersaults in the laboratory. The robot changes its leg length in flight to control rotation rate. This in turn provides a mechanism for controlling the landing attitude of the robot once airborne. (4) Passively stabilized layout somersault: We have found that the passive structure of a gymnast, the configuration of masses and compliances, can stabilize inherently unstable maneuvers. This means that body biomechanics could play a larger role in controlling behavior than is generally thought. We used a physical 'doll' model and computer simulation to illustrate the point. (5) Twisting: Some gymnastic maneuvers require twisting. We are studying how to couple the biomechanics of the system to its control to produce efficient, stable twisting maneuvers.

  5. Combinators for Paraconsistent Attitudes

    DEFF Research Database (Denmark)

    Villadsen, Jørgen

    2001-01-01

    In order to analyse the semantics of natural language sentences a translation into a partial type logic using lexical and logical combinators is presented. The sentences cover a fragment of English with propositional attitudes like knowledge, belief and assertion. A combinator is a closed term...... used for embedded sentences expressing propositional attitudes, thereby allowing for inconsistency without explosion (also called paraconsistency), and is based on a few key equalities for the connectives giving four truth values (truth, falsehood, and undefinedness with negative and positive polarity...

  6. Automated ISS Flight Utilities

    Science.gov (United States)

    Offermann, Jan Tuzlic

    2016-01-01

    EVADES output. As mentioned above, GEnEVADOSE makes extensive use of ROOT version 6, the data analysis framework developed at the European Organization for Nuclear Research (CERN), and the code is written to the C++11 standard (as are the other projects). My second project is the Automated Mission Reference Exposure Utility (AMREU).Unlike GEnEVADOSE, AMREU is a combination of three frameworks written in both Python and C++, also making use of ROOT (and PyROOT). Run as a combination of daily and weekly cron jobs, these macros query the SRAG database system to determine the active ISS missions, and query minute-by-minute radiation dose information from ISS-TEPC (Tissue Equivalent Proportional Counter), one of the radiation detectors onboard the ISS. Using this information, AMREU creates a corrected data set of daily radiation doses, addressing situations where TEPC may be offline or locked up by correcting doses for days with less than 95% live time (the total amount time the instrument acquires data) by averaging the past 7 days. As not all errors may be automatically detectable, AMREU also allows for manual corrections, checking an updated plaintext file each time it runs. With the corrected data, AMREU generates cumulative dose plots for each mission, and uses a Python script to generate a flight note file (.docx format) containing these plots, as well as information sections to be filled in and modified by the space weather environment officers with information specific to the week. AMREU is set up to run without requiring any user input, and it automatically archives old flight notes and information files for missions that are no longer active. My other projects involve cleaning up a large data set from the Charged Particle Directional Spectrometer (CPDS), joining together many different data sets in order to clean up information in SRAG SQL databases, and developing other automated utilities for displaying information on active solar regions, that may be used by the

  7. 14 CFR 27.151 - Flight controls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flight controls. 27.151 Section 27.151... STANDARDS: NORMAL CATEGORY ROTORCRAFT Flight Flight Characteristics § 27.151 Flight controls. (a) Longitudinal, lateral, directional, and collective controls may not exhibit excessive breakout force, friction...

  8. 14 CFR 29.151 - Flight controls.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flight controls. 29.151 Section 29.151... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Flight Characteristics § 29.151 Flight controls. (a) Longitudinal, lateral, directional, and collective controls may not exhibit excessive breakout force, friction...

  9. F-14 in banked flight

    Science.gov (United States)

    1979-01-01

    NASA 991, an F-14 Navy Tomcat designated the F-14 (1X), is seen here in banked flight over the desert on a research flight at NASA's Dryden Flight Research Center, Edwards, California. The F-14 was used at Dryden between 1979 and 1985 in extensive high-angle-of-attack and spin-control-and-recovery tests. The NASA/Navy program, which included 212 total flights, acheived considerable improvement in the F-14 high-angle-of-attack flying qualities, improved departure and spin resistance, and contributed to substantial improvements in reducing 'wing rock,' (i.e., tilting from one side to another), at high angles of attack. The Navy had been experiencing inadvertant spin entries caused by the F-14's aileron rudder interconnect. The NASA/Navy/Grumman team developed and tested 4 different configurations of the aileron rudder interconnect to address the spin problem. These problems prompted the Navy to ask the manufacturer, Grumman, and NASA to investigate the issue. NASA 991 had numerous special additions for high-angle-of-attack and spin-recovery research. These included a battery-powered auxiliary power unit, a flight test nose boom, and a special spin recovery system, consisting of forward mounted, hydraulically actuated canards and an emergency spin chute. NASA's F-14 was first flown by NASA research pilots, but was later flown by Grumman, and by Navy test pilots from Patuxent River Naval Air Station (NAS). The Navy test flights with the spin research vehicle constituted the first program that incorporated air combat maneuvering in its test flights at Dryden. The Navy brought F-14s from Point Mugu and Miramar NAS in San Diego to test the new spin control laws in combat situations. Although the new control laws proved valuable, the Navy did not incorporate them into production F-14s until the F-14D, nearly 15 years later.

  10. Aurora Flight Sciences' Perseus B Remotely Piloted Aircraft in Flight

    Science.gov (United States)

    1998-01-01

    A long, slender wing and a pusher propeller at the rear characterize the Perseus B remotely piloted research aircraft, seen here during a test flight in June 1998. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third generation of the Perseus design, which began with the Perseus Proof-Of-Concept aircraft. Perseus was initially developed as part of NASA's Small High-Altitude Science Aircraft (SHASA) program, which later evolved into the ERAST

  11. Wages, Amenities and Negative Attitudes

    DEFF Research Database (Denmark)

    Waisman, Gisela; Larsen, Birthe

    We exploit the regional variation in negative attitudes towards immigrants to Sweden in order to analyse the consequences of the attitudes on immigrants welfare. We find that attitudes towards immigrants are of importance: they both affect their labour market outcomes and their quality of life. We...... interpret the negative effect on wages as evidence of labour market discrimination. We estimate the welfare effects of negative attitudes, through their wage and local amenities, for immigrants with different levels of skills, origin, gender and age....

  12. Intergenerational Attitudes toward Maternal Employment.

    Science.gov (United States)

    Heaven, Catherine P.; McCluskey-Fawcett, Kathleen

    Intergenerational attitudes toward child care were examined among college-age students and their parents through the use of questionnaires, the Beliefs About the Consequences of Maternal Employment Scale (BACMEC), and the Bias in Attitudes toward Women Scale (BIAS). Findings indicated that traditional attitudes were more prevalent in males of both…

  13. Predictors of Attitudes toward Childlessness.

    Science.gov (United States)

    Spreadbury, Connie

    The study assessed young adults' attitudes toward childlessness and identified certain factors which predict positive or negative attitudes toward childlessness. The author anticipated finding changes in attitudes because of recent social developments such as awareness of world overpopulation, availability of birth control methods, pressure for…

  14. Changing attitudes through persuasive communication.

    Science.gov (United States)

    Clarke, A

    Nurses are uniquely placed to provide effective health education with the aim of promoting attitude and behavioural change. This article explores the literature relating to attitude formation, attitude change and the nature of persuasive communication, and identifies specific strategies that will be useful to all nurses.

  15. Eating attitudes among adolescents.

    Science.gov (United States)

    Maor, Noga Roguin; Sayag, Shlomit; Dahan, Rachel; Hermoni, Doron

    2006-09-01

    Israeli youth lead 27 western countries in dieting. The prevalence of eating disorders has been rising in the last 30 years, causing social problems and medical complications. To examine the prevalence of eating disorders among high school students in a region in northern Israel (Misgav) and to examine the relationship between the parents' employment status and the subject's eating disorder. A structured questionnaire was administered to collect demographic data. The short version of the Eating Attitudes Test (EAT-26) was used to evaluate the subject's attitudes toward and preoccupation with food, dieting, eating, physical appearance, and personal control over eating. Of 360 students approached, 283 (78%) completed the self-report EAT-26. One of every 5 females and one in every 20 males had an abnormal eating attitude. The rate of pathologic EAT-26 results, 20.8%, falls within the high range of similar community-based samples of female adolescents. There were no differences in EAT-26 score between students with an employed or unemployed mother; however, there was a trend for higher EAT-26 scores among those whose father was unemployed (21.4% vs. 12.7%, chi2 = 0.14). The findings support our hypothesis of a relatively high rate of abnormal eating attitudes (as reflected by high EAT-26 score) in this population. Another possible risk factor is having an unemployed father, which warrants further research and attention. Our next step is to introduce an intervention program in the school and to study its effect.

  16. Working Memory and Attitudes

    Science.gov (United States)

    Jung, Eun Sook; Reid, Norman

    2009-01-01

    Working memory capacity has been shown to be an important factor in controlling understanding in the sciences. Attitudes related to studies in the sciences are also known to be important in relation to success in learning. It might be argued that if working memory capacity is a rate controlling feature of learning and success in understanding…

  17. Attitudes of Success.

    Science.gov (United States)

    Pendarvis, Faye

    This document investigates the attitudes of successful individuals, citing the achievement of established goals as the criteria for success. After offering various definitions of success, the paper focuses on the importance of self-esteem to success and considers ways by which the self-esteem of students can be improved. Theories of human behavior…

  18. Attitude toward Visionary Leadership.

    Science.gov (United States)

    Lesourd, Sandra J.; And Others

    1992-01-01

    Formulates descriptive research findings into a utilitarian tool for principal leadership development programs. An instrument measuring attitude toward a (visionary) leadership ideal was developed, administered, and analyzed. Previous research findings were summarized. Results showed that the instrument would help assess individual acceptance of…

  19. Student Attitude Inventory - 1971.

    Science.gov (United States)

    Gillmore, Gerald M.; Aleamoni, Lawrence M.

    This 42-item Student Attitude Inventory (SAI) was administered to entering college freshmen at the University of Illinois (see TM 001 015). The SAI items are divided into nine categories on the basis of content as follows: voting behavior, drug usage, financial, Viet Nam war, education, religious behavior, pollution, housing, and alienation. A…

  20. Attitudes to nuclear waste

    International Nuclear Information System (INIS)

    Sjoeberg, L.; Drottz-Sjoeberg, B.M.

    1993-08-01

    This is a study of risk perception and attitudes with regard to nuclear waste. Two data sets are reported. In the first set, data were obtained from a survey of the general population, using an extensive questionnaire. The second set constituted a follow-up 7 years later, with a limited number of questions. The data showed that people considered the topic of nuclear waste risks to be very important and that they were not convinced that the technological problems had been solved. Experts associated with government agencies were moderately trusted, while those employed by the nuclear industry were much distrusted by some respondents, and very much trusted by others. Moral obligations to future generations were stressed. A large portion (more than 50 per cent) of the variances in risk perception could be explained by attitude to nuclear power, general risk sensitivity and trust in expertise. Most background variables, except gender, had little influence on risk perception and attitudes. The follow-up study showed that the attitude to nuclear power had become more positive over time, but that people still doubted that the problems of nuclear waste disposal had been solved. 49 refs

  1. Optimal magnetic attitude control

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Markley, F.L.

    1999-01-01

    because control torques can only be generated perpendicular to the local geomagnetic field vector. This has been a serious obstacle for using magnetorquer based control for three-axis stabilization of a low earth orbit satellite. The problem of controlling the spacecraft attitude using only magnetic...

  2. Stereotypes and Welfare Attitudes

    DEFF Research Database (Denmark)

    Hedegaard, Troels Fage

    2014-01-01

    recipients lacking both the financial incentives and the will to work. According to theories of the impact of media on welfare attitudes, this had the potential to undermine public support. A two-wave panel survey, however, showed only a small drop in public support for spending on social assistance...

  3. In-flight sleep of flight crew during a 7-hour rest break: implications for research and flight safety.

    Science.gov (United States)

    Signal, T Leigh; Gander, Philippa H; van den Berg, Margo J; Graeber, R Curtis

    2013-01-01

    To assess the amount and quality of sleep that flight crew are able to obtain during flight, and identify factors that influence the sleep obtained. Flight crew operating flights between Everett, WA, USA and Asia had their sleep recorded polysomnographically for 1 night in a layover hotel and during a 7-h in-flight rest opportunity on flights averaging 15.7 h. Layover hotel and in-flight crew rest facilities onboard the Boeing 777-200ER aircraft. Twenty-one male flight crew (11 Captains, mean age 48 yr and 10 First Officers, mean age 35 yr). N/A. Sleep was recorded using actigraphy during the entire tour of duty, and polysomnographically in a layover hotel and during the flight. Mixed model analysis of covariance was used to determine the factors affecting in-flight sleep. In-flight sleep was less efficient (70% vs. 88%), with more nonrapid eye movement Stage 1/Stage 2 and more frequent awakenings per h (7.7/h vs. 4.6/h) than sleep in the layover hotel. In-flight sleep included very little slow wave sleep (median 0.5%). Less time was spent trying to sleep and less sleep was obtained when sleep opportunities occurred during the first half of the flight. Multivariate analyses suggest age is the most consistent factor affecting in-flight sleep duration and quality. This study confirms that even during long sleep opportunities, in-flight sleep is of poorer quality than sleep on the ground. With longer flight times, the quality and recuperative value of in-flight sleep is increasingly important for flight safety. Because the age limit for flight crew is being challenged, the consequences of age adversely affecting sleep quantity and quality need to be evaluated.

  4. Hawkmoth flight performance in tornado-like whirlwind vortices.

    Science.gov (United States)

    Ortega-Jimenez, Victor Manuel; Mittal, Rajat; Hedrick, Tyson L

    2014-06-01

    Vertical vortex systems such as tornadoes dramatically affect the flight control and stability of aircraft. However, the control implications of smaller scale vertically oriented vortex systems for small fliers such as animals or micro-air vehicles are unknown. Here we examined the flapping kinematics and body dynamics of hawkmoths performing hovering flights (controls) and maintaining position in three different whirlwind intensities with transverse horizontal velocities of 0.7, 0.9 and 1.2 m s(-1), respectively, generated in a vortex chamber. The average and standard deviation of yaw and pitch were respectively increased and reduced in comparison with hovering flights. Average roll orientation was unchanged in whirlwind flights but was more variable from wingbeat to wingbeat than in hovering. Flapping frequency remained unchanged. Wingbeat amplitude was lower and the average stroke plane angle was higher. Asymmetry was found in the angle of attack between right and left wings during both downstroke and upstroke at medium and high vortex intensities. Thus, hawkmoth flight control in tornado-like vortices is achieved by a suite of asymmetric and symmetric changes to wingbeat amplitude, stroke plane angle and principally angle of attack.

  5. Hawkmoth flight performance in tornado-like whirlwind vortices

    International Nuclear Information System (INIS)

    Ortega-Jimenez, Victor Manuel; Hedrick, Tyson L; Mittal, Rajat

    2014-01-01

    Vertical vortex systems such as tornadoes dramatically affect the flight control and stability of aircraft. However, the control implications of smaller scale vertically oriented vortex systems for small fliers such as animals or micro-air vehicles are unknown. Here we examined the flapping kinematics and body dynamics of hawkmoths performing hovering flights (controls) and maintaining position in three different whirlwind intensities with transverse horizontal velocities of 0.7, 0.9 and 1.2 m s −1 , respectively, generated in a vortex chamber. The average and standard deviation of yaw and pitch were respectively increased and reduced in comparison with hovering flights. Average roll orientation was unchanged in whirlwind flights but was more variable from wingbeat to wingbeat than in hovering. Flapping frequency remained unchanged. Wingbeat amplitude was lower and the average stroke plane angle was higher. Asymmetry was found in the angle of attack between right and left wings during both downstroke and upstroke at medium and high vortex intensities. Thus, hawkmoth flight control in tornado-like vortices is achieved by a suite of asymmetric and symmetric changes to wingbeat amplitude, stroke plane angle and principally angle of attack. (papers)

  6. System Identification of Flight Mechanical Characteristics

    OpenAIRE

    Larsson, Roger

    2013-01-01

    With the demand for more advanced fighter aircraft, relying on relaxed stability or even unstable flight mechanical characteristics to gain flight performance, more focus has been put on model-based system engineering to help with the design work. The flight control system design is one important part that relies on this modeling. Therefore it has become more important to develop flight mechanical models that are highly accurate in the whole flight envelop. For today’s newly developed fighter...

  7. Supersonic Retropropulsion Flight Test Concepts

    Science.gov (United States)

    Post, Ethan A.; Dupzyk, Ian C.; Korzun, Ashley M.; Dyakonov, Artem A.; Tanimoto, Rebekah L.; Edquist, Karl T.

    2011-01-01

    NASA's Exploration Technology Development and Demonstration Program has proposed plans for a series of three sub-scale flight tests at Earth for supersonic retropropulsion, a candidate decelerator technology for future, high-mass Mars missions. The first flight test in this series is intended to be a proof-of-concept test, demonstrating successful initiation and operation of supersonic retropropulsion at conditions that replicate the relevant physics of the aerodynamic-propulsive interactions expected in flight. Five sub-scale flight test article concepts, each designed for launch on sounding rockets, have been developed in consideration of this proof-of-concept flight test. Commercial, off-the-shelf components are utilized as much as possible in each concept. The design merits of the concepts are compared along with their predicted performance for a baseline trajectory. The results of a packaging study and performance-based trade studies indicate that a sounding rocket is a viable launch platform for this proof-of-concept test of supersonic retropropulsion.

  8. NASA Aerosciences Activities to Support Human Space Flight

    Science.gov (United States)

    LeBeau, Gerald J.

    2011-01-01

    The Lyndon B. Johnson Space Center (JSC) has been a critical element of the United State's human space flight program for over 50 years. It is the home to NASA s Mission Control Center, the astronaut corps, and many major programs and projects including the Space Shuttle Program, International Space Station Program, and the Orion Project. As part of JSC's Engineering Directorate, the Applied Aeroscience and Computational Fluid Dynamics Branch is charted to provide aerosciences support to all human spacecraft designs and missions for all phases of flight, including ascent, exo-atmospheric, and entry. The presentation will review past and current aeroscience applications and how NASA works to apply a balanced philosophy that leverages ground testing, computational modeling and simulation, and flight testing, to develop and validate related products. The speaker will address associated aspects of aerodynamics, aerothermodynamics, rarefied gas dynamics, and decelerator systems, involving both spacecraft vehicle design and analysis, and operational mission support. From these examples some of NASA leading aerosciences challenges will be identified. These challenges will be used to provide foundational motivation for the development of specific advanced modeling and simulation capabilities, and will also be used to highlight how development activities are increasing becoming more aligned with flight projects. NASA s efforts to apply principles of innovation and inclusion towards improving its ability to support the myriad of vehicle design and operational challenges will also be briefly reviewed.

  9. 14 CFR 25.865 - Fire protection of flight controls, engine mounts, and other flight structure.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fire protection of flight controls, engine... Design and Construction Fire Protection § 25.865 Fire protection of flight controls, engine mounts, and other flight structure. Essential flight controls, engine mounts, and other flight structures located in...

  10. Tunneling Flight Time, Chemistry, and Special Relativity.

    Science.gov (United States)

    Petersen, Jakob; Pollak, Eli

    2017-09-07

    Attosecond ionization experiments have not resolved the question "What is the tunneling time?". Different definitions of tunneling time lead to different results. Second, a zero tunneling time for a material particle suggests that the nonrelativistic theory includes speeds greater than the speed of light. Chemical reactions, occurring via tunneling, should then not be considered in terms of a nonrelativistic quantum theory calling into question quantum dynamics computations on tunneling reactions. To answer these questions, we define a new experimentally measurable paradigm, the tunneling flight time, and show that it vanishes for scattering through an Eckart or a square barrier, irrespective of barrier length or height, generalizing the Hartman effect. We explain why this result does not lead to experimental measurement of speeds greater than the speed of light. We show that this tunneling is an incoherent process by comparing a classical Wigner theory with exact quantum mechanical computations.

  11. The Effect of Advertising on Attitude Accessibility, Attitude Confidence, and the Attitude-Behavior Relationship.

    OpenAIRE

    Berger, Ida E; Mitchell, Andrew A

    1989-01-01

    The influence of advertising repetition on several non-evaluative dimensions of attitudes and the strength of the relationship between attitudes and behavior are examined. The results indicate that attitudes formed on the basis of repeated ad exposure are similar to those formed on the basis of direct experience in that they are more accessible from memory, held with more confidence, and are more predictive of subsequent behavior than are attitudes based on a single ad exposure. The results a...

  12. Influencing Factors of the Initiation Point in the Parachute-Bomb Dynamic Detonation System

    Science.gov (United States)

    Qizhong, Li; Ye, Wang; Zhongqi, Wang; Chunhua, Bai

    2017-12-01

    The parachute system has been widely applied in modern armament design, especially for the fuel-air explosives. Because detonation of fuel-air explosives occurs during flight, it is necessary to investigate the influences of the initiation point to ensure successful dynamic detonation. In fact, the initiating position exist the falling area in the fuels, due to the error of influencing factors. In this paper, the major influencing factors of initiation point were explored with airdrop and the regularity between initiation point area and factors were obtained. Based on the regularity, the volume equation of initiation point area was established to predict the range of initiation point in the fuel. The analysis results showed that the initiation point appeared area, scattered on account of the error of attitude angle, secondary initiation charge velocity, and delay time. The attitude angle was the major influencing factors on a horizontal axis. On the contrary, secondary initiation charge velocity and delay time were the major influencing factors on a horizontal axis. Overall, the geometries of initiation point area were sector coupled with the errors of the attitude angle, secondary initiation charge velocity, and delay time.

  13. Human tolerance to space flight

    Science.gov (United States)

    Huntoon, C. L.

    1989-01-01

    Medical studies of astronauts and cosmonauts before, during, and after space missions have identified several effects of weightlessness and other factors that influence the ability of humans to tolerate space flight. Weightlessness effects include space motion sickness, cardiovascular abnormalities, reduction in immune system function, loss of red blood cells, loss of bone mass, and muscle atrophy. Extravehicular activity (EVA) increases the likelihood that decompression sickness may occur. Radiation also gives reason for concern about health of crewmembers, and psychological factors are important on long-term flights. Countermeasures that have been used include sensory preadaptation, prebreathing and use of various air mixtures for EVA, loading with water and electrolytes, exercise, use of pharmacological agents and special diets, and psychological support. It appears that humans can tolerate and recover satisfactorily from at least one year of space flight, but a number of conditions must be further ameliorated before long-duration missions can be considered routine.

  14. X-36 during First Flight

    Science.gov (United States)

    1997-01-01

    The remotely-piloted X-36 Tailless Fighter Agility Research Aircraft climbs out from Rogers Dry Lake at the Dryden Flight Research Center on its first flight in May 1997. The aircraft flew for five minutes and reached an altitude of approximately 4,900 feet. The NASA/Boeing X-36 Tailless Fighter Agility Research Aircraft program successfully demonstrated the tailless fighter design using advanced technologies to improve the maneuverability and survivability of possible future fighter aircraft. The program met or exceeded all project goals. For 31 flights during 1997 at the Dryden Flight Research Center, Edwards, California, the project team examined the aircraft's agility at low speed / high angles of attack and at high speed / low angles of attack. The aircraft's speed envelope reached up to 206 knots (234 mph). This aircraft was very stable and maneuverable. It handled very well. The X-36 vehicle was designed to fly without the traditional tail surfaces common on most aircraft. Instead, a canard forward of the wing was used as well as split ailerons and an advanced thrust-vectoring nozzle for directional control. The X-36 was unstable in both pitch and yaw axes, so an advanced, single-channel digital fly-by-wire control system (developed with some commercially available components) was put in place to stabilize the aircraft. Using a video camera mounted in the nose of the aircraft and an onboard microphone, the X-36 was remotely controlled by a pilot in a ground station virtual cockpit. A standard fighter-type head-up display (HUD) and a moving-map representation of the vehicle's position within the range in which it flew provided excellent situational awareness for the pilot. This pilot-in-the-loop approach eliminated the need for expensive and complex autonomous flight control systems and the risks associated with their inability to deal with unknown or unforeseen phenomena in flight. Fully fueled the X-36 prototype weighed approximately 1,250 pounds. It was 19

  15. Income, Amenities and Negative Attitudes

    DEFF Research Database (Denmark)

    Waisman, Gisela; Larsen, Birthe

    2016-01-01

    We exploit the regional variation in negative attitudes towards immigrants to Sweden in order to analyse the consequences of negative attitudes on refugees’ utility from labour income and amenities. We find that attitudes towards immigrants are important: while they affect mainly the refugees......’ quality of life, they also affect their income. We estimate the utility effects of negative attitudes for refugees with different levels of education and gender. We also analyse how the size of the refugees’ networks relate to their quality of life and income as well as how negative attitudes towards...

  16. Stakeholder Attitudes, Knowledge and Engagement in Local Road Systems Planning and Decision Making

    Science.gov (United States)

    2017-10-01

    Political and policy dynamics associated with local road systems planning, management, and financing merit special attention. This study: 1) analyzes stakeholder attitudes, knowledge, and engagement about financing for local road system management, t...

  17. Toward Accurate On-Ground Attitude Determination for the Gaia Spacecraft

    Science.gov (United States)

    Samaan, Malak A.

    2010-03-01

    The work presented in this paper concerns the accurate On-Ground Attitude (OGA) reconstruction for the astrometry spacecraft Gaia in the presence of disturbance and of control torques acting on the spacecraft. The reconstruction of the expected environmental torques which influence the spacecraft dynamics will be also investigated. The telemetry data from the spacecraft will include the on-board real-time attitude, which is of order of several arcsec. This raw attitude is the starting point for the further attitude reconstruction. The OGA will use the inputs from the field coordinates of known stars (attitude stars) and also the field coordinate differences of objects on the Sky Mapper (SM) and Astrometric Field (AF) payload instruments to improve this raw attitude. The on-board attitude determination uses a Kalman Filter (KF) to minimize the attitude errors and produce a more accurate attitude estimation than the pure star tracker measurement. Therefore the first approach for the OGA will be an adapted version of KF. Furthermore, we will design a batch least squares algorithm to investigate how to obtain a more accurate OGA estimation. Finally, a comparison between these different attitude determination techniques in terms of accuracy, robustness, speed and memory required will be evaluated in order to choose the best attitude algorithm for the OGA. The expected resulting accuracy for the OGA determination will be on the order of milli-arcsec.

  18. Flight Trajectory Planning for Fixed-Wing Aircraft in Loss of Thrust Emergencies

    OpenAIRE

    Paul, Saswata; Hole, Frederick; Zytek, Alexandra; Varela, Carlos A.

    2017-01-01

    Loss of thrust emergencies-e.g., induced by bird/drone strikes or fuel exhaustion-create the need for dynamic data-driven flight trajectory planning to advise pilots or control UAVs. While total loss of thrust trajectories to nearby airports can be pre-computed for all initial points in a 3D flight plan, dynamic aspects such as partial power and airplane surface damage must be considered for accuracy. In this paper, we propose a new Dynamic Data-Driven Avionics Software (DDDAS) approach which...

  19. Enabling Electric Propulsion for Flight

    Science.gov (United States)

    Ginn, Starr Renee

    2015-01-01

    Team Seedling project AFRC and LaRC 31ft distributed electric propulsion wing on truck bed up 75 miles per hour for coefficient of lift validation. Convergent Aeronautic Solutions project, sub-project Convergent Electric Propulsion Technologies AFRC, LaRC and GRC, re-winging a 4 passenger Tecnam aircraft with a 31ft distributed electric propulsion wing. Advanced Air Transport Technologies (Fixed Wing), Hybrid Electric Research Theme, developing a series hybrid ironbird and flight sim to study integration and performance challenges in preparation for a 1-2 MW flight project.

  20. CHANGES IN FLIGHT TRAINEE PERFORMANCE FOLLOWING SYNTHETIC HELICOPTER FLIGHT TRAINING.

    Science.gov (United States)

    CARO, PAUL W., JR.; ISLEY, ROBERT N.

    A STUDY WAS CONDUCTED AT THE U.S. ARMY PRIMARY HELICOPTER SCHOOL, FORT WOLTERS, TEXAS, TO DETERMINE WHETHER THE USE OF A HELICOPTER TRAINING DEVICE WOULD IMPROVE STUDENT PERFORMANCE DURING SUBSEQUENT HELICOPTER CONTACT FLIGHT TRAINING. SUBJECTS WERE TWO EXPERIMENTAL GROUPS AND TWO CONTROL GROUPS OF WARRANT OFFICER CANDIDATES ENROLLED FOR A…