WorldWideScience

Sample records for attitude flight dynamics

  1. Flight and attitude dynamics measurements of an instrumented Frisbee

    Science.gov (United States)

    Lorenz, Ralph D.

    2005-03-01

    In-flight measurements are made of the translational accelerations and attitude motion of a hand-thrown flying disc using miniaturized accelerometers and other sensors and a microcontroller data acquisition system. The experiments explore the capabilities and limitations of sensors on a rapidly rotating platform moving in air, and illustrate several of the complex gyrodynamic aspects of Frisbee flight. The data give insight into the biomechanics of Frisbee launch, and indicate lift, drag and pitch moment coefficients consistent with previous wind-tunnel measurements. The experiments constitute an instructive exercise in aerospace vehicle systems integration and in attitude reconstruction, and open the way to guided disc wings using control surfaces actuated during specific spin phases determined by onboard sensors.

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

    Science.gov (United States)

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

    2016-01-01

    The NASA Magnetospheric Multiscale mission, launched on Mar. 12, 2015, is flying four spinning spacecraft in highly elliptical orbits to study the magnetosphere of the Earth. Extensive attitude data is being collected, including spin rate, spin axis orientation, and nutation rate. The paper will discuss the various environmental disturbance torques that act on the spacecraft, and will describe the observed results of these torques. In addition, a slow decay in spin rate has been observed for all four spacecraft in the extended periods between maneuvers. It is shown that this despin is consistent with the effects of an additional disturbance mechanism, namely that produced by the Active Spacecraft Potential Control devices. Finally, attitude dynamics data is used to analyze a micrometeoroid/orbital debris impact event with MMS4 that occurred on Feb. 2, 2016.

  3. 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.

  4. On characteristic modeling of a class of flight vehicles’attitude dynamics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The characteristic modeling problem of flight vehicles’attitude dynamics is considered in this paper.In terms of the affine nonlinear system with triangle form of flight vehicles’attitude dynamics,a general method is presented to compress the dynamics into the characteristic model parameters,by introducing the time scale of nonlinear systems and a class of system states related compress functions.The parameter region and limit of the characteristic model are also given.From the given parameter region it is seen that the bound of the characteristic model parameters is dependent on the sampling period,the modeling error,the system order and the system change rate.The modeling error of the established characteristic model can be arbitrarily small according to the control precision,showing the difference between the characteristic model and other model reduction methods,that is,no system information is lost using this approach.On the basis of this modeling approach,the characteristic model of the flexible satellite attitude is established,as well as the bound and limit of the parameters,which sets a theoretical foundation for characteristic model based control design of flight vehicles.

  5. 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.

  6. 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 seconds of freefall (0 g) followed by 40 seconds 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.

  7. UAV Flight Dynamics

    OpenAIRE

    Philip Scott Blackwelder

    2015-01-01

    In the interest of promoting the integration of hybrid-electric power train into the aviation industry, research is being conducted by North Carolina State University to establish the feasibility of electrified power train in a small scale unmanned aerial vehicle (UAV). To accomplish this, it is first necessary to understand dynamics of the system to calculate the required power associated with each portions of the aircraft’s mission. Though research that has been conducted...

  8. Dynamic flight stability of a bumblebee in forward flight

    Institute of Scientific and Technical Information of China (English)

    Yan Xiong; Mao Sun

    2008-01-01

    The longitudinal dynamic flight stability of a bumblebee in forward flight is studied.The method of computational fluid dynamics is used to compute the aerodynamic derivatives and the techniques of eigenvalue and eigenvector analysis are employed for solving the equations of motion.The primary findings are as the following.The forward flight of the bumblebee is not dynamically stable due to the existence of one(or two)unstable or approximately neutrally stable natural modes of motion.At hovering to medium flight speed[flight speed ue=(0-3.5)m s-1;advance ratio J=0-0.44],the flight is weakly unstable or approximately neutrally stable;at high speed(ue=4.5 m s-1;J=0.57),the flight becomes strongly unstable(initial disturbance double its value in only 3.5 wingbeats).

  9. Flight Dynamics and Controls Discipline Overview

    Science.gov (United States)

    Theodore, Colin R.

    2012-01-01

    This presentation will touch topics, including but not limited to, the objectives and challenges of flight dynamics and controls that deal with the pilot and the cockpit's technology, the flight dynamics and controls discipline tasks, and the full envelope of flight dynamics modeling. In addition, the LCTR 7x10-ft wind tunnel test will also be included along with the optimal trajectories for noise abatement and its investigations on handling quality. Furthermore, previous experiments and their complying results will also be discussed.

  10. Cassini Attitude Control Flight Software: from Development to In-Flight Operation

    Science.gov (United States)

    Brown, Jay

    2008-01-01

    The Cassini Attitude and Articulation Control Subsystem (AACS) Flight Software (FSW) has achieved its intended design goals by successfully guiding and controlling the Cassini-Huygens planetary mission to Saturn and its moons. This paper describes an overview of AACS FSW details from early design, development, implementation, and test to its fruition of operating and maintaining spacecraft control over an eleven year prime mission. Starting from phases of FSW development, topics expand to FSW development methodology, achievements utilizing in-flight autonomy, and summarize lessons learned during flight operations which can be useful to FSW in current and future spacecraft missions.

  11. Attitude Determination Using a MEMS-Based Flight Information Measurement Unit

    Directory of Open Access Journals (Sweden)

    Yu-Heng Lin

    2011-12-01

    Full Text Available Obtaining precise attitude information is essential for aircraft navigation and control. This paper presents the results of the attitude determination using an in-house designed low-cost MEMS-based flight information measurement unit. This study proposes a quaternion-based extended Kalman filter to integrate the traditional quaternion and gravitational force decomposition methods for attitude determination algorithm. The proposed extended Kalman filter utilizes the evolution of the four elements in the quaternion method for attitude determination as the dynamic model, with the four elements as the states of the filter. The attitude angles obtained from the gravity computations and from the electronic magnetic sensors are regarded as the measurement of the filter. The immeasurable gravity accelerations are deduced from the outputs of the three axes accelerometers, the relative accelerations, and the accelerations due to body rotation. The constraint of the four elements of the quaternion method is treated as a perfect measurement and is integrated into the filter computation. Approximations of the time-varying noise variances of the measured signals are discussed and presented with details through Taylor series expansions. The algorithm is intuitive, easy to implement, and reliable for long-term high dynamic maneuvers. Moreover, a set of flight test data is utilized to demonstrate the success and practicality of the proposed algorithm and the filter design.

  12. Space station dynamics, attitude control and momentum management

    Science.gov (United States)

    Sunkel, John W.; Singh, Ramen P.; Vengopal, Ravi

    1989-01-01

    The Space Station Attitude Control System software test-bed provides a rigorous environment for the design, development and functional verification of GN and C algorithms and software. The approach taken for the simulation of the vehicle dynamics and environmental models using a computationally efficient algorithm is discussed. The simulation includes capabilities for docking/berthing dynamics, prescribed motion dynamics associated with the Mobile Remote Manipulator System (MRMS) and microgravity disturbances. The vehicle dynamics module interfaces with the test-bed through the central Communicator facility which is in turn driven by the Station Control Simulator (SCS) Executive. The Communicator addresses issues such as the interface between the discrete flight software and the continuous vehicle dynamics, and multi-programming aspects such as the complex flow of control in real-time programs. Combined with the flight software and redundancy management modules, the facility provides a flexible, user-oriented simulation platform.

  13. Sliding Mode Implementation of an Attitude Command Flight Control System for a Helicopter in Hover

    Directory of Open Access Journals (Sweden)

    D. J. McGeoch

    2005-01-01

    Full Text Available This paper presents an investigation into the design of a flight control system, using a decoupled non-linear sliding mode control structure, designed using a linearised, 9th order representation of the dynamics of a PUMA helicopter in hover. The controllers are then tested upon a higher order, non-linear helicopter model, called RASCAL. This design approach is used for attitude command flight control implementation and the control performance is assessed in the terms of handling qualities through the Aeronautical Design Standards for Rotorcraft (ADS-33. In this context a linearised approximation of the helicopter system is used to design an SMC control scheme. These controllers have been found to yield a system that satisfies the Level 1 handling qualities set out by ADS-33. 

  14. Flight Vehicle Attitude Determination Using the Modified Rodrigues Parameters

    Institute of Scientific and Technical Information of China (English)

    Chen Jizheng; Yuan Jianping; Fang Qun

    2008-01-01

    There are two attitude estimation algorithms based on the different representations of attitude errors when modified Rodrigues parameters are applied to attitude estimation. The first is multiplicative error attitude estimator (MEAE), whose attitude error is expressed by the modified Rodrigues parameters representing the rotation from the estimated to the true attitude. The second is subtractive error attitude estimator (SEAE), whose attitude error is expressed by the arithmetic difference between the true and the estimated attitudes. It is proved that the two algorithms are equivalent in the case of small attitude errors. It is possible to describe rotation without encountering singularity by switching between the modified Rodrigues parameters and their shadow parameters. The attitude parameter switching does not bring disturbance to MEAE, but it does to SEAE. This article introduces a modification to eliminate the disturbance on SEAE,and simulation results demonstrate the efficacy of the presented algorithm.

  15. Space station configuration and flight dynamics identification

    Science.gov (United States)

    Metter, E.; Milman, M. H.

    1985-01-01

    The Space Station will be assembled in low earth orbit by a combination of deployable and space erectable modules that are progressively integrated during successive flights of the Shuttle. The crew assisted space construction will result in a configuration which is a large scale composite of structural elements having connectivity with a wide range of possible end conditions and imprecisely known dynamic characteristics. The generic applications of Flight Dynamics Identification to the candidate Space Station configurations currently under consideration are described. Identification functions are categorized, and the various methods for extracting parameter estimates are correlated with the sensing of parameter estimates are correlated with the sensing of specific characteristics of interest to both engineering subsystems and users of the Station's commercial and scientific facilities. Onboard implementation architecture and constraints are discussed from the viewpoint of maximizing integration of the Identification process with the flight subsystem's data and signal flow.

  16. 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.

  17. Development of helicopter attitude axes controlled hover flight without pilot assistance and vehicle crashes

    Science.gov (United States)

    Simon, Miguel

    In this work, we show how to computerize a helicopter to fly attitude axes controlled hover flight without the assistance of a pilot and without ever crashing. We start by developing a helicopter research test bed system including all hardware, software, and means for testing and training the helicopter to fly by computer. We select a Remote Controlled helicopter with a 5 ft. diameter rotor and 2.2 hp engine. We equip the helicopter with a payload of sensors, computers, navigation and telemetry equipment, and batteries. We develop a differential GPS system with cm accuracy and a ground computerized navigation system for six degrees of freedom (6-DoF) free flight while tracking navigation commands. We design feedback control loops with yet-to-be-determined gains for the five control "knobs" available to a flying radio-controlled (RC) miniature helicopter: engine throttle, main rotor collective pitch, longitudinal cyclic pitch, lateral cyclic pitch, and tail rotor collective pitch. We develop helicopter flight equations using fundamental dynamics, helicopter momentum theory and blade element theory. The helicopter flight equations include helicopter rotor equations of motions, helicopter rotor forces and moments, helicopter trim equations, helicopter stability derivatives, and a coupled fuselage-rotor helicopter 6-DoF model. The helicopter simulation also includes helicopter engine control equations, a helicopter aerodynamic model, and finally helicopter stability and control equations. The derivation of a set of non-linear equations of motion for the main rotor is a contribution of this thesis work. We design and build two special test stands for training and testing the helicopter to fly attitude axes controlled hover flight, starting with one axis at a time and progressing to multiple axes. The first test stand is built for teaching and testing controlled flight of elevation and yaw (i.e., directional control). The second test stand is built for teaching and

  18. Attitude Control Algorithm for Reusable Launch Vehicle in Reentry Flight Phase

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jun; JI Peng-fei; HU Wei-jun

    2009-01-01

    An attitude control algorithm for reusable launch vehicle (RLV) in reentry phase is proposed based on sliding mode variable structure control technique. The aerodynamic characteristics of RLV vary rapidly, and the serious uncertainties and nonlinearities exist in the reentry flight phase. As an example, American X-34 technology demonstrator is investigated. The chattering brought by the variable structure control technique is eliminated efficiently by choosing a suitable reaching law and a sign function. A control mode of reaction control system is presented based on the RCS scheme of X-34 vehicle. As two different attitude control effectors, aerosurfaces and RCS, are employed in the reentry flight phase, a composite control strategy based on the dynamic pressure variety is presented. Also, an actuator model and a RCS thruster model are built. Analysis and nonlinear simulation results show that the sliding mode variable structure controller achieves better performance, the overshoot and steady-state error are only 0.7% and 0.04° respectively.

  19. Modeling and Flight Data Analysis of Spacecraft Dynamics with a Large Solar Array Paddle

    Science.gov (United States)

    Iwata, Takanori; Maeda, Ken; Hoshino, Hiroki

    2007-01-01

    The Advanced Land Observing Satellite (ALOS) was launched on January 24 2006 and has been operated successfully since then. This satellite has the attitude dynamics characterized by three large flexible structures, four large moving components, and stringent attitude/pointing stability requirements. In particular, it has one of the largest solar array paddles. Presented in this paper are flight data analyses and modeling of spacecraft attitude motion induced by the large solar array paddle. On orbit attitude dynamics was first characterized and summarized. These characteristic motions associated with the solar array paddle were identified and assessed. These motions are thermally induced motion, the pitch excitation by the paddle drive, and the role excitation. The thermally induced motion and the pitch excitation by the paddle drive were modeled and simulated to verify the mechanics of the motions. The control law updates implemented to mitigate the attitude vibrations are also reported.

  20. Dynamic Flight Simulation of aircraft and its comparison to Flight tests

    Directory of Open Access Journals (Sweden)

    Reza Khaki

    2015-09-01

    Full Text Available Nowadays obtaining data for air vehicles researches and analyses is very expensive and risky through the flight tests. Therefore using flight simulation is usually used for the mentioned researches by aerospace science researchers. In this paper, dynamic flight simulation has been performed by airplane nonlinear equations modelling. In these equations, aerodynamic coefficients and stability derivatives have an important role. Therefore, the stability derivatives for typical aircraft are calculated on various flight conditions by analytical and numerical methods. Flight conditions include of Mach number, altitude, angle of attack, control surfaces and CG position variations. The obtained derivatives are used in the form of look up table for dynamic flight simulation and virtual flight. In order to validate the simulation results, the under investigation maneuvres parameters are recorded during many real flights. The obtained data from flight tests are compared with the outputs of flight simulations. The results indicate that less than 13% differences are found in different parts of the maneuvres.

  1. 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.

  2. 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.

  3. System identification approach for determining flight dynamical characteristics of an airship from flight data

    OpenAIRE

    Kornienko, Andrei

    2006-01-01

    The knowledge of dynamical characteristics of a flight vehicle is necessary for the control system design and realization of high fidelity flight simulators. The development of a flight mechanical model and determination of its basic components, as for example mass properties and the major aerodynamic terms, addresses a complex process involving various analytical, numerical and experimental techniques. The objective of this dissertation is a determination of the basic dynamical character...

  4. Unsteady aerodynamics modeling for flight dynamics application

    Science.gov (United States)

    Wang, Qing; He, Kai-Feng; Qian, Wei-Qi; Zhang, Tian-Jiao; Cheng, Yan-Qing; Wu, Kai-Yuan

    2012-02-01

    In view of engineering application, it is practicable to decompose the aerodynamics into three components: the static aerodynamics, the aerodynamic increment due to steady rotations, and the aerodynamic increment due to unsteady separated and vortical flow. The first and the second components can be presented in conventional forms, while the third is described using a one-order differential equation and a radial-basis-function (RBF) network. For an aircraft configuration, the mathematical models of 6-component aerodynamic coefficients are set up from the wind tunnel test data of pitch, yaw, roll, and coupled yawroll large-amplitude oscillations. The flight dynamics of an aircraft is studied by the bifurcation analysis technique in the case of quasi-steady aerodynamics and unsteady aerodynamics, respectively. The results show that: (1) unsteady aerodynamics has no effect upon the existence of trim points, but affects their stability; (2) unsteady aerodynamics has great effects upon the existence, stability, and amplitudes of periodic solutions; and (3) unsteady aerodynamics changes the stable regions of trim points obviously. Furthermore, the dynamic responses of the aircraft to elevator deflections are inspected. It is shown that the unsteady aerodynamics is beneficial to dynamic stability for the present aircraft. Finally, the effects of unsteady aerodynamics on the post-stall maneuverability are analyzed by numerical simulation.

  5. Unsteady aerodynamics modeling for flight dynamics application

    Institute of Scientific and Technical Information of China (English)

    Qing Wang; Kai-Feng He; Wei-Qi Qian; Tian-Jiao Zhang; Yan-Qing Cheng; Kai-Yuan Wu

    2012-01-01

    In view of engineering application,it is practicable to decompose the aerodynamics into three components:the static aerodynamics,the aerodynamic increment due to steady rotations,and the aerodynamic increment due to unsteady separated and vortical flow.The first and the second components can be presented in conventional forms,while the third is described using a one-order differential equation and a radial-basis-function (RBF) network. For an aircraft configuration,the mathematical models of 6-component aerodynamic coefficients are set up from the wind tunnel test data of pitch,yaw,roll,and coupled yawroll large-amplitude oscillations.The flight dynamics of an aircraft is studied by the bifurcation analysis technique in the case of quasi-steady aerodynamics and unsteady aerodynamics,respectively.The results show that:(1) unsteady aerodynamics has no effect upon the existence of trim points,but affects their stability; (2) unsteady aerodynamics has great effects upon the existence,stability,and amplitudes of periodic solutions; and (3) unsteady aerodynamics changes the stable regions of trim points obviously.Furthermore,the dynamic responses of the aircraft to elevator deflections are inspected.It is shown that the unsteady aerodynamics is beneficial to dynamic stability for the present aircraft.Finally,the effects of unsteady aerodynamics on the post-stall maneuverability are analyzed by numerical simulation.

  6. Dynamic flight stability of hovering insects

    Institute of Scientific and Technical Information of China (English)

    Mao Sun; Jikang Wang; Yan Xiong

    2007-01-01

    The equations of motion of an insect with flapping wings are derived and then simplified to that of a flying body using the "rigid body" assumption. On the basis of the simplified equations of motion, the longitudinal dynamic flight stability of four insects (hoverfly, cranefly, dronefly and hawkmoth) in hovering flight is studied (the mass of the insects ranging from 11 to 1,648 mg and wingbeat frequency from 26 to 157Hz). The method of computational fluid dynamics is used to compute the aerodynamic derivatives and the techniques of eigenvalue and eigenvector analysis are used to solve the equations of motion. The validity of the "rigid body" assumption is tested and how differencesin size and wing kinematics influence the applicability of the "rigid body" assumption is investigated. The primary findings are: (1) For insects considered in the present study and those with relatively high wingbeat frequency (hover-fly, drone fly and bumblebee), the "rigid body" assumptionis reasonable, and for those with relatively low wingbeatfrequency (cranefly and howkmoth), the applicability of the"rigid body" assumption is questionable. (2) The same three natural modes of motion as those reported recently for a bumblebee are identified, i.e., one unstable oscillatory mode,one stable fast subsidence mode and one stable slow subsidence mode. (3) Approximate analytical expressions of the eigenvalues, which give physical insight into the genesis of the natural modes of motion, are derived. The expressions identify the speed derivative Mu (pitching moment produced by unit horizontal speed) as the primary source of the unstable oscillatory mode and the stable fast subsidence mode and Zw (vertical force produced by unit vertical speed) as the primary source of the stable slow subsidence mode.

  7. 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.

  8. 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

  9. Impact of Vehicle Flexibility on IRVE-II Flight Dynamics

    Science.gov (United States)

    Bose, David M.; Toniolo, Matthew D.; Cheatwood, F. M.; Hughes, Stephen J.; Dillman, Robert A.

    2011-01-01

    The Inflatable Re-entry Vehicle Experiment II (IRVE-II) successfully launched from Wallops Flight Facility (WFF) on August 17, 2009. The primary objectives of this flight test were to demonstrate inflation and re-entry survivability, assess the thermal and drag performance of the reentry vehicle, and to collect flight data for refining pre-flight design and analysis tools. Post-flight analysis including trajectory reconstruction outlined in O Keefe3 demonstrated that the IRVE-II Research Vehicle (RV) met mission objectives but also identified a few anomalies of interest to flight dynamics engineers. Most notable of these anomalies was high normal acceleration during the re-entry pressure pulse. Deflection of the inflatable aeroshell during the pressure pulse was evident in flight video and identified as the likely cause of the anomaly. This paper provides a summary of further post-flight analysis with particular attention to the impact of aeroshell flexibility on flight dynamics and the reconciliation of flight performance with pre-flight models. Independent methods for estimating the magnitude of the deflection of the aeroshell experienced on IRVE-II are discussed. The use of the results to refine models for pre-flight prediction of vehicle performance is then described.

  10. 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.

  11. Flight dynamics modeling of a small ducted fan aerial vehicle based on parameter identification

    Institute of Scientific and Technical Information of China (English)

    Wang Zhengjie; Liu Zhijun; Fan Ningjun; Guo Meifang

    2013-01-01

    This paper presents a simple and useful modeling method to acquire a dynamics model of an aerial vehicle containing unknown parameters using mechanism modeling, and then to design different identification experiments to identify the parameters based on the sources and features of its unknown parameters. Based on the mathematical model of the aerial vehicle acquired by modeling and identification, a design for the structural parameters of the attitude control system is carried out, and the results of the attitude control flaps are verified by simulation experiments and flight tests of the aerial vehicle. Results of the mathematical simulation and flight tests show that the mathematical model acquired using parameter identification is comparatively accurate and of clear mechanics, and can be used as the reference and basis for the structural design.

  12. Flight Dynamic Simulation with Nonlinear Aeroelastic Interaction using the ROM-ROM Procedure Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. proposes to develop an integrated flight dynamics simulation capability with nonlinear aeroelastic interactions by combining a flight dynamics...

  13. In-flight measurement of upwind dynamic soaring in albatrosses

    Science.gov (United States)

    Sachs, Gottfried

    2016-03-01

    In-flight measurement results on upwind flight of albatrosses using dynamic soaring are presented. It is shown how the birds manage to make progress against the wind on the basis of small-scale dynamic soaring maneuvers. For this purpose, trajectory features, motion quantities and mechanical energy relationships as well as force characteristics are analyzed. The movement on a large-scale basis consists of a tacking type flight technique which is composed of dynamic soaring cycle sequences with alternating orientation to the left and right. It is shown how this is performed by the birds so that they can achieve a net upwind flight without a transversal large-scale movement and how this compares with downwind or across wind flight. Results on upwind dynamic soaring are presented for low and high wind speed cases. It is quantified how much the tacking trajectory length is increased when compared with the beeline distance. The presented results which are based on in-flight measurements of free flying albatrosses were achieved with an in-house developed GPS-signal tracking method yielding the required high precision for the small-scale dynamic soaring flight maneuvers.

  14. Unified Nonlinear Flight Dynamics and Aeroelastic Simulator Tool Project

    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...

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

    Directory of Open Access Journals (Sweden)

    Mingying Huo

    Full Text Available 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.

  16. 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.

  17. Cassini Attitude Control Operations Flight Rules and How They are Enforced

    Science.gov (United States)

    Burk, Thomas; Bates, David

    2008-01-01

    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. Cassini deployed the European-built Huygens probe which descended through the Titan atmosphere and landed on its surface on January 14, 2005. Operating the Cassini spacecraft is a complex scientific, engineering, and management job. In order to safely operate the spacecraft, a large number of flight rules were developed. These flight rules must be enforced throughout the lifetime of the Cassini spacecraft. Flight rules are defined as any operational limitation imposed by the spacecraft system design, hardware, and software, violation of which would result in spacecraft damage, loss of consumables, loss of mission objectives, loss and/or degradation of science, and less than optimal performance. Flight rules require clear description and rationale. Detailed automated methods have been developed to insure the spacecraft is continuously operated within these flight rules. An overview of all the flight rules allocated to the Cassini Attitude Control and Articulation Subsystem and how they are enforced is presented in this paper.

  18. 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...... with modeling external noise sources often arise. The special CHAMP configuration with two star tracker cameras mounted fixed together provides an excellent opportunity to determine the AIA in-flight using the inter boresight angle....

  19. Flight Dynamics Mission Support and Quality Assurance Process

    Science.gov (United States)

    Oh, InHwan

    1996-01-01

    This paper summarizes the method of the Computer Sciences Corporation Flight Dynamics Operation (FDO) quality assurance approach to support the National Aeronautics and Space Administration Goddard Space Flight Center Flight Dynamics Support Branch. Historically, a strong need has existed for developing systematic quality assurance using methods that account for the unique nature and environment of satellite Flight Dynamics mission support. Over the past few years FDO has developed and implemented proactive quality assurance processes applied to each of the six phases of the Flight Dynamics mission support life cycle: systems and operations concept, system requirements and specifications, software development support, operations planing and training, launch support, and on-orbit mission operations. Rather than performing quality assurance as a final step after work is completed, quality assurance has been built in as work progresses in the form of process assurance. Process assurance activities occur throughout the Flight Dynamics mission support life cycle. The FDO Product Assurance Office developed process checklists for prephase process reviews, mission team orientations, in-progress reviews, and end-of-phase audits. This paper will outline the evolving history of FDO quality assurance approaches, discuss the tailoring of Computer Science Corporations's process assurance cycle procedures, describe some of the quality assurance approaches that have been or are being developed, and present some of the successful results.

  20. 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.

  1. Quasi-satellite dynamics in formation flight

    Science.gov (United States)

    Mikkola, Seppo; Prioroc, Claudiu-Lucian

    2016-04-01

    The quasi-satellite phenomenon makes two celestial bodies to fly near each other (Mikkola et al.) and that effect can be used also to make artificial satellites move in tandem. We consider formation flight of two or three satellites in low eccentricity near Earth orbits. With the help of weak ion thrusters, it is possible to accomplish tandem flight. With ion thrusters, it is also possible to mimic many kinds of mutual force laws between the satellites. We found that both a constant repulsive force or an attractive force that decreases with the distance are able to preserve the formation in which the eccentricities cause the actual relative motion and the weak thrusters keep the mean longitude difference small. Initial values are important for the formation flight but very exact adjustment of orbital elements is not important. Simplicity is one of our goals in this study and this result is achieved at least in the way that, when constant force thrusters are used, the satellites only need to detect the directions of the other ones to fly in tandem. A repulsive acceleration of the order of 10-6 times the Earth attraction, is enough to effectively eliminate the disruptive effects of all the perturbations at least for a time-scale of years.

  2. Quasi-satellite dynamics in formation flight

    CERN Document Server

    Mikkola, Seppo

    2016-01-01

    The quasi-satellite (QS) phenomenon makes two celestial bodies to fly near each other (Mikkola et al. 2006) and that effect can be used also to make artificial satellites move in tandem. We consider formation flight of two or three satellites in low eccentricity near Earth orbits. With the help of weak ion thrusters it is possible to accomplish tandem flight. With ion thrusters it is also possible to mimic many kinds of mutual force laws between the satellites. We found that both a constant repulsive force or an attractive force that decreases with the distance are able to preserve the formation in which the eccentricities cause the actual relative motion and the weak thrusters keep the mean longitude difference small. Initial values are important for the formation flight but very exact adjustment of orbital elements is not important. Simplicity is one of our goals in this study and this result is achieved at least in the way that, when constant force thrusters are used, the satellites only need to detect the...

  3. Analytical and flight investigation of the influence of rotor and other high-order dynamics on helicopter flight-control system bandwidth

    Science.gov (United States)

    Chen, R. T. N.; Hindson, W. S.

    1985-01-01

    The increasing use of highly augmented digital flight-control systems in modern military helicopters prompted an examination of the influence of rotor dynamics and other high-order dynamics on control-system performance. A study was conducted at NASA Ames Research Center to correlate theoretical predictions of feedback gain limits in the roll axis with experimental test data obtained from a variable-stability research helicopter. Feedback gains, the break frequency of the presampling sensor filter, and the computational frame time of the flight computer were systematically varied. The results, which showed excellent theoretical and experimental correlation, indicate that the rotor-dynamics, sensor-filter, and digital-data processing delays can severely limit the usable values of the roll-rate and roll-attitude feedback gains.

  4. Dynamic Modeling from Flight Data with Unknown Time Skews

    Science.gov (United States)

    Morelli, Eugene A.

    2016-01-01

    A method for estimating dynamic model parameters from flight data with unknown time skews is described and demonstrated. The method combines data reconstruction, nonlinear optimization, and equation-error parameter estimation in the frequency domain to accurately estimate both dynamic model parameters and the relative time skews in the data. Data from a nonlinear F-16 aircraft simulation with realistic noise, instrumentation errors, and arbitrary time skews were used to demonstrate the approach. The approach was further evaluated using flight data from a subscale jet transport aircraft, where the measured data were known to have relative time skews. Comparison of modeling results obtained from time-skewed and time-synchronized data showed that the method accurately estimates both dynamic model parameters and relative time skew parameters from flight data with unknown time skews.

  5. Flight Dynamic Simulation with Nonlinear Aeroelastic Interaction using the ROM-ROM Procedure Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. (ZONA) proposes to develop an integrated flight dynamics simulation capability with nonlinear aeroelastic interactions by combining a flight...

  6. Progress Toward a Format Standard for Flight Dynamics Models

    Science.gov (United States)

    Jackson, E. Bruce; Hildreth, Bruce L.

    2006-01-01

    In the beginning, there was FORTRAN, and it was... not so good. But it was universal, and all flight simulator equations of motion were coded with it. Then came ACSL, C, Ada, C++, C#, Java, FORTRAN-90, Matlab/Simulink, and a number of other programming languages. Since the halcyon punch card days of 1968, models of aircraft flight dynamics have proliferated in training devices, desktop engineering and development computers, and control design textbooks. With the rise of industry teaming and increased reliance on simulation for procurement decisions, aircraft and missile simulation models are created, updated, and exchanged with increasing frequency. However, there is no real lingua franca to facilitate the exchange of models from one simulation user to another. The current state-of-the-art is such that several staff-months if not staff-years are required to 'rehost' each release of a flight dynamics model from one simulation environment to another one. If a standard data package or exchange format were to be universally adopted, the cost and time of sharing and updating aerodynamics, control laws, mass and inertia, and other flight dynamic components of the equations of motion of an aircraft or spacecraft simulation could be drastically reduced. A 2002 paper estimated over $ 6 million in savings could be realized for one military aircraft type alone. This paper describes the efforts of the American Institute of Aeronautics and Astronautics (AIAA) to develop a standard flight dynamic model exchange standard based on XML and HDF-5 data formats.

  7. 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.

  8. Dynamics and nonlinear attitude control of multibody space systems

    Science.gov (United States)

    Rui, Chunlei

    In this dissertation, we study dynamics and attitude control problems for a multibody system in space. The key feature of this work is the systematic use of shape changes as three dimensional attitude controls. Control models are identified for a general class of multibody space systems that are controlled by thrusters, reaction wheels, and/or joint actuators. The important role of shape change in attitude maneuvers for a multibody space system is identified and shape change is recognized as a means of attitude control. Formulas that quantify three dimensional attitude changes induced by periodic shape changes, rotation of reaction wheels and nonzero angular momentum are developed. The formulas prove fundamental for development of numerous attitude control algorithms. Explicit construction procedures are developed for shape changes that accomplish a desired three dimensional reconfiguration of a free-floating multibody space system with zero angular momentum with prescribed accuracy. The control computation involves evaluation of certain Lie brackets and solution of a simple system of algebraic equations. Explicit construction procedures are developed for shape changes that accomplish a desired three dimensional reorientation of a free-floating multibody space system with constant nonzero angular momentum with prescribed accuracy. Control algorithms are provided for reorientation of a multibody space system to one of its relative equilibria. Explicit control algorithms are developed for reaction wheel and shape changes that accomplish a desired three dimensional reorientation for a spacecraft system containing a single reaction wheel and a single movable appendage. Characterization of shape changes that enhance effectiveness of reaction wheels and joint actuators is given, and control algorithms are provided for effective simultaneous attitude changes and shape changes. Feedback attitude control laws are developed for three dimensional attitude maneuvers of a

  9. 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.

  10. Dynamic flight stability of a hovering model dragonfly.

    Science.gov (United States)

    Liang, Bin; Sun, Mao

    2014-05-01

    The longitudinal dynamic flight stability of a model dragonfly at hovering flight is studied, using the method of computational fluid dynamics to compute the stability derivatives and the techniques of eigenvalue and eigenvector analysis for solving the equations of motion. Three natural modes of motion are identified for the hovering flight: one unstable oscillatory mode, one stable fast subsidence mode and one stable slow subsidence mode. The flight is dynamically unstable owing to the unstable oscillatory mode. The instability is caused by a pitch-moment derivative with respect to horizontal velocity. The damping force and moment derivatives (with respect to horizontal and vertical velocities and pitch-rotational velocity, respectively) weaken the instability considerably. The aerodynamic interaction between the forewing and the hindwing does not have significant effect on the stability properties. The dragonfly has similar stability derivatives, hence stability properties, to that of a one-wing-pair insect at normal hovering, but there are differences in how the derivatives are produced because of the highly inclined stroke plane of the dragonfly.

  11. Identification of Helicopter Rigid Body Dynamics from Flight Data.

    Directory of Open Access Journals (Sweden)

    Jatinder Singh

    1998-01-01

    Full Text Available This paper discusses helicopter modelling and identification related aspects. By applying thesystem identification methodology, longitudinal and lateral-directional rigid body helicopter dynamics are identified from flight data. Aerodynamic parameters from single input excitation as wellas multimanoeuver evaluation are estimated utilising output-error approach. The formulatedmathematical models yield adequate fit to measured time histories. Results obtained from the proof-of-match for model validation indicate that the identified derivatives can satisfactorily predictlongitudinal dynamics to a given arbitrary input. It is further demonstrated for the present study thatlateral body dynamics can be adequately predicted by including cross-coupling terms in the estimation model.

  12. 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.

  13. 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.

  14. 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.

  15. Autocoded Stellar Dynamic Attitude Estimation Filter for DEMETER

    Science.gov (United States)

    Pontet, B.; Pittet, C.; Fallet, C.; Penet, R.

    2009-05-01

    This paper demonstrates how CNES enhanced AOCS (Attitude and Orbit Control System) software development and validation by using automatic code generation. We are using Matlab/Simulink® for the development and validation of a new attitude estimation filter to fly on board the Demeter satellite. After a presentation of the Demeter satellite and Myriade micro satellite series, this paper shortly describes the new stellar dynamic attitude estimation filter we are implementing. Then we review the several steps followed in order to develop this filter. Next we discuss the validation process, focussing on what we used to do, what we are doing now and what we propose to do in the future. And finally this paper shows a synthesis on the performances. In conclusion, automatic code generation enhances the quality of AOCS software.

  16. Multiagent Flight Control in Dynamic Environments with Cooperative Coevolutionary Algorithms

    Science.gov (United States)

    Knudson, Matthew D.; Colby, Mitchell; Tumer, Kagan

    2014-01-01

    Dynamic flight environments in which objectives and environmental features change with respect to time pose a difficult problem with regards to planning optimal flight paths. Path planning methods are typically computationally expensive, and are often difficult to implement in real time if system objectives are changed. This computational problem is compounded when multiple agents are present in the system, as the state and action space grows exponentially. In this work, we use cooperative coevolutionary algorithms in order to develop policies which control agent motion in a dynamic multiagent unmanned aerial system environment such that goals and perceptions change, while ensuring safety constraints are not violated. Rather than replanning new paths when the environment changes, we develop a policy which can map the new environmental features to a trajectory for the agent while ensuring safe and reliable operation, while providing 92% of the theoretically optimal performance

  17. Evaluating the Handling Qualities of Flight Control Systems Including Nonlinear Aircraft and System Dynamics

    Science.gov (United States)

    Lin, Raymond Chao

    The handling qualities evaluation of nonlinear aircraft systems is an area of concern in loss-of-control (LOC) prevention. The Get Transfer Function (GetTF) method was demonstrated for evaluating the handling qualities of flight control systems and aircraft containing nonlinearities. NASA's Generic Transport Model (GTM), a nonlinear model of a civilian jet transport aircraft, was evaluated. Using classical techniques, the stability, control, and augmentation (SCAS) systems were designed to control pitch rate, roll rate, and airspeed. Hess's structural pilot model was used to model pilot dynamics in pitch and roll-attitude tracking. The simulated task was simultaneous tracking of, both, pitch and roll attitudes. Eight cases were evaluated: 1) gain increase of pitch-attitude command signal, 2) gain increase of roll-attitude command signal, 3) gain reduction of elevator command signal, 4) backlash in elevator actuator, 5) combination 3 and 4 in elevator actuator, 6) gain reduction of aileron command signal, 7) backlash in aileron actuator, and 8) combination of 6 and 7 in aileron actuator. The GetTF method was used to estimate the transfer function approximating a linear relationship between the proprioceptive signal of the pilot model and the command input. The transfer function was then used to predict the handling qualities ratings (HQR) and pilot-induced oscillation ratings (PIOR). The HQR is based on the Cooper-Harper rating scale. In pitch-attitude tracking, the nominal aircraft is predicted to have Level 2* HQRpitch and 2 pitch tracking exercise was also conducted to validate the structural pilot model.

  18. Effect of wing flexibility on aircraft flight dynamics

    OpenAIRE

    Qiao, Yuqing

    2012-01-01

    The purpose of this thesis is to give a preliminary investigation into the effect of wing deformation on flight dynamics. The candidate vehicle is FW-11 which is a flying wing configuration aircraft with high altitude and long endurance characteristics. The aeroelastic effect may be significant for this type of configuration. Two cases, the effect of flexible wing on lift distribution and on roll effectiveness during the cruise condition with different inertial parameters are investigated. ...

  19. Pattern Recognition for a Flight Dynamics Monte Carlo Simulation

    Science.gov (United States)

    Restrepo, Carolina; Hurtado, John E.

    2011-01-01

    The design, analysis, and verification and validation of a spacecraft relies heavily on Monte Carlo simulations. Modern computational techniques are able to generate large amounts of Monte Carlo data but flight dynamics engineers lack the time and resources to analyze it all. The growing amounts of data combined with the diminished available time of engineers motivates the need to automate the analysis process. Pattern recognition algorithms are an innovative way of analyzing flight dynamics data efficiently. They can search large data sets for specific patterns and highlight critical variables so analysts can focus their analysis efforts. This work combines a few tractable pattern recognition algorithms with basic flight dynamics concepts to build a practical analysis tool for Monte Carlo simulations. Current results show that this tool can quickly and automatically identify individual design parameters, and most importantly, specific combinations of parameters that should be avoided in order to prevent specific system failures. The current version uses a kernel density estimation algorithm and a sequential feature selection algorithm combined with a k-nearest neighbor classifier to find and rank important design parameters. This provides an increased level of confidence in the analysis and saves a significant amount of time.

  20. Flight Dynamics and Control of Elastic Hypersonic Vehicles Uncertainty Modeling

    Science.gov (United States)

    Chavez, Frank R.; Schmidt, David K.

    1994-01-01

    It has been shown previously that hypersonic air-breathing aircraft exhibit strong aeroelastic/aeropropulsive dynamic interactions. To investigate these, especially from the perspective of the vehicle dynamics and control, analytical expressions for key stability derivatives were derived, and an analysis of the dynamics was performed. In this paper, the important issue of model uncertainty, and the appropriate forms for representing this uncertainty, is addressed. It is shown that the methods suggested in the literature for analyzing the robustness of multivariable feedback systems, which as a prerequisite to their application assume particular forms of model uncertainty, can be difficult to apply on real atmospheric flight vehicles. Also, the extent to which available methods are conservative is demonstrated for this class of vehicle dynamics.

  1. 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)

  2. Simulation of Attitude and Trajectory Dynamics and Control of Multiple Spacecraft

    Science.gov (United States)

    Stoneking, Eric T.

    2009-01-01

    Agora software is a simulation of spacecraft attitude and orbit dynamics. It supports spacecraft models composed of multiple rigid bodies or flexible structural models. Agora simulates multiple spacecraft simultaneously, supporting rendezvous, proximity operations, and precision formation flying studies. The Agora environment includes ephemerides for all planets and major moons in the solar system, supporting design studies for deep space as well as geocentric missions. The environment also contains standard models for gravity, atmospheric density, and magnetic fields. Disturbance force and torque models include aerodynamic, gravity-gradient, solar radiation pressure, and third-body gravitation. In addition to the dynamic and environmental models, Agora supports geometrical visualization through an OpenGL interface. Prototype models are provided for common sensors, actuators, and control laws. A clean interface accommodates linking in actual flight code in place of the prototype control laws. The same simulation may be used for rapid feasibility studies, and then used for flight software validation as the design matures. Agora is open-source and portable across computing platforms, making it customizable and extensible. It is written to support the entire GNC (guidance, navigation, and control) design cycle, from rapid prototyping and design analysis, to high-fidelity flight code verification. As a top-down design, Agora is intended to accommodate a large range of missions, anywhere in the solar system. Both two-body and three-body flight regimes are supported, as well as seamless transition between them. Multiple spacecraft may be simultaneously simulated, enabling simulation of rendezvous scenarios, as well as formation flying. Built-in reference frames and orbit perturbation dynamics provide accurate modeling of precision formation control.

  3. Coupled nonlinear aeroelasticity and flight dynamics of fully flexible aircraft

    Science.gov (United States)

    Su, Weihua

    This dissertation introduces an approach to effectively model and analyze the coupled nonlinear aeroelasticity and flight dynamics of highly flexible aircraft. A reduced-order, nonlinear, strain-based finite element framework is used, which is capable of assessing the fundamental impact of structural nonlinear effects in preliminary vehicle design and control synthesis. The cross-sectional stiffness and inertia properties of the wings are calculated along the wing span, and then incorporated into the one-dimensional nonlinear beam formulation. Finite-state unsteady subsonic aerodynamics is used to compute airloads along lifting surfaces. Flight dynamic equations are then introduced to complete the aeroelastic/flight dynamic system equations of motion. Instead of merely considering the flexibility of the wings, the current work allows all members of the vehicle to be flexible. Due to their characteristics of being slender structures, the wings, tail, and fuselage of highly flexible aircraft can be modeled as beams undergoing three dimensional displacements and rotations. New kinematic relationships are developed to handle the split beam systems, such that fully flexible vehicles can be effectively modeled within the existing framework. Different aircraft configurations are modeled and studied, including Single-Wing, Joined-Wing, Blended-Wing-Body, and Flying-Wing configurations. The Lagrange Multiplier Method is applied to model the nodal displacement constraints at the joint locations. Based on the proposed models, roll response and stability studies are conducted on fully flexible and rigidized models. The impacts of the flexibility of different vehicle members on flutter with rigid body motion constraints, flutter in free flight condition, and roll maneuver performance are presented. Also, the static stability of the compressive member of the Joined-Wing configuration is studied. A spatially-distributed discrete gust model is incorporated into the time simulation

  4. Geometric Tracking Control of the Attitude Dynamics of a Rigid Body on SO(3)

    OpenAIRE

    Lee, Taeyoung

    2010-01-01

    This paper provides new results for a tracking control of the attitude dynamics of a rigid body. Both of the attitude dynamics and the proposed control system are globally expressed on the special orthogonal group, to avoid complexities and ambiguities associated with other attitude representations such as Euler angles or quaternions. By selecting an attitude error function carefully, we show that the proposed control system guarantees a desirable tracking performance uniformly for nontrivial...

  5. 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

  6. Dynamic Echo Information Guides Flight in the Big Brown Bat.

    Science.gov (United States)

    Warnecke, Michaela; Lee, Wu-Jung; Krishnan, Anand; Moss, Cynthia F

    2016-01-01

    Animals rely on sensory feedback from their environment to guide locomotion. For instance, visually guided animals use patterns of optic flow to control their velocity and to estimate their distance to objects (e.g., Srinivasan et al., 1991, 1996). In this study, we investigated how acoustic information guides locomotion of animals that use hearing as a primary sensory modality to orient and navigate in the dark, where visual information is unavailable. We studied flight and echolocation behaviors of big brown bats as they flew under infrared illumination through a corridor with walls constructed from a series of individual vertical wooden poles. The spacing between poles on opposite walls of the corridor was experimentally manipulated to create dense/sparse and balanced/imbalanced spatial structure. The bats' flight trajectories and echolocation signals were recorded with high-speed infrared motion-capture cameras and ultrasound microphones, respectively. As bats flew through the corridor, successive biosonar emissions returned cascades of echoes from the walls of the corridor. The bats flew through the center of the corridor when the pole spacing on opposite walls was balanced and closer to the side with wider pole spacing when opposite walls had an imbalanced density. Moreover, bats produced shorter duration echolocation calls when they flew through corridors with smaller spacing between poles, suggesting that clutter density influences features of the bat's sonar signals. Flight speed and echolocation call rate did not, however, vary with dense and sparse spacing between the poles forming the corridor walls. Overall, these data demonstrate that bats adapt their flight and echolocation behavior dynamically when flying through acoustically complex environments. PMID:27199690

  7. Dynamic echo information guides flight in the big brown bat

    Directory of Open Access Journals (Sweden)

    Michaela Warnecke

    2016-04-01

    Full Text Available Animals rely on sensory feedback from their environment to guide locomotion. For instance, visually guided animals use patterns of optic flow to control their velocity and to estimate their distance to objects (e.g. Srinivasan et al. 1991, 1996. In this study, we investigated how acoustic information guides locomotion of animals that use hearing as a primary sensory modality to orient and navigate in the dark, where visual information is unavailable. We studied flight and echolocation behaviors of big brown bats as they flew under infrared illumination through a corridor with walls constructed from a series of individual vertical wooden poles. The spacing between poles on opposite walls of the corridor was experimentally manipulated to create dense/sparse and balanced/imbalanced spatial structure. The bats’ flight trajectories and echolocation signals were recorded with high-speed infrared motion-capture cameras and ultrasound microphones, respectively. As bats flew through the corridor, successive biosonar emissions returned cascades of echoes from the walls of the corridor. The bats flew through the center of the corridor when the pole spacing on opposite walls was balanced and closer to the side with wider pole spacing when opposite walls had an imbalanced density. Moreover, bats produced shorter duration echolocation calls when they flew through corridors with smaller spacing between poles, suggesting that clutter density influences features of the bat’s sonar signals. Flight speed and echolocation call rate did not, however, vary with dense and sparse spacing between the poles forming the corridor walls. Overall, these data demonstrate that bats adapt their flight and echolocation behavior dynamically when flying through acoustically complex environments.

  8. Evolution and Reengineering of NASA's Flight Dynamics Facility (FDF)

    Science.gov (United States)

    Stengle, Thomas; Hoge, Susan

    2008-01-01

    The NASA Goddard Space Flight Center's Flight Dynamics Facility (FDF) is a multimission support facility that performs ground navigation and spacecraft trajectory design services for a wide range of scientific satellites. The FDF also supports the NASA Space Network by providing orbit determination and tracking data evaluation services for the Tracking Data Relay Satellite System (TDRSS). The FDF traces its history to early NASA missions in the 1960's, including navigation support to the Apollo lunar missions. Over its 40 year history, the FDF has undergone many changes in its architecture, services offered, missions supported, management approach, and business operation. As a fully reimbursable facility (users now pay 100% of all costs for FDF operations and sustaining engineering activities), the FDF has faced significant challenges in recent years in providing mission critical products and services at minimal cost while defining and implementing upgrades necessary to meet future mission demands. This paper traces the history of the FDF and discusses significant events in the past that impacted the FDF infrastructure and/or business model, and the events today that are shaping the plans for the FDF in the next decade. Today's drivers for change include new mission requirements, the availability of new technology for spacecraft navigation, and continued pressures for cost reduction from FDF users. Recently, the FDF completed an architecture study based on these drivers that defines significant changes planned for the facility. This paper discusses the results of this study and a proposed implementation plan. As a case study in how flight dynamics operations have evolved and will continue to evolve, this paper focuses on two periods of time (1992 and the present) in order to contrast the dramatic changes that have taken place in the FDF. This paper offers observations and plans for the evolution of the FDF over the next ten years. Finally, this paper defines the

  9. Lift Enhancement by Dynamically Changing Wingspan in Forward Flapping Flight

    CERN Document Server

    Wang, Shizhao; He, Guowei; Liu, Tianshu

    2013-01-01

    Stretching and retracting wingspan has been widely observed in the flight of birds and bats, and its effects on the aerodynamic performance particularly lift generation are intriguing. The rectangular flat-plate flapping wing with a sinusoidally stretching and retracting wingspan is proposed as a simple model of biologically-inspired dynamic morphing wings. Direct numerical simulations of the low-Reynolds-number flows around the flapping morphing wing in a parametric space are conducted by using immersed boundary method. It is found that the instantaneous and time-averaged lift coefficients of the wing can be significantly enhanced by dynamically changing wingspan in a flapping cycle. The lift enhancement is caused not only by changing the lifting surface area, but also manipulating the flow structures that are responsible to the generation of the vortex lift. The physical mechanisms behind the lift enhancement are explored by examining the three-dimensional flow structures around the flapping wing.

  10. 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.

  11. Equilibrium Positions for UAV Flight by Dynamic Soaring

    Directory of Open Access Journals (Sweden)

    Bingjie Zhu

    2015-01-01

    Full Text Available Dynamic soaring is a special flying technique designed to allow UAVs (unmanned aerial vehicles to extract energy from wind gradient field and enable UAVs to increase the endurance. In order to figure out the energy-extraction mechanisms in dynamic soaring, a noninertial wind relative reference frame of aircraft is built. In the noninertial frame, there is an inertial force which is created by gradient wind field. When the wind gradient (GW and the components of airspeed (vzvx are positive, inertial force (F makes positive work to the aircraft. In the meantime, an equilibrium position theory of dynamic soaring is proposed. At the equilibrium positions, the increased potential energy is greater than the wasted kinetic energy when the aircraft is flying upwards. The mechanical energy is increased in this way, and the aircraft can store energy for flight. According to the extreme value theory, contour line figures of the maximum function and the component of airspeed (vz are obtained to find out the aircraft’s lifting balance allowance in dynamic soaring. Moreover, this equilibrium position theory can also help to conduct an aircraft to acquire energy from the environment constantly.

  12. Satellite Attitude Control System Design considering the Fuel Slosh Dynamics

    Directory of Open Access Journals (Sweden)

    Luiz Carlos Gadelha de Souza

    2014-01-01

    Full Text Available The design of the satellite attitude control system (ACS becomes more complex when the satellite structure has different type of components like, flexible solar panels, antennas, mechanical manipulators, and tanks with fuel. A crucial interaction can occur between the fuel slosh motion and the satellite rigid motion during translational and/or rotational manoeuvre since these interactions can change the satellite centre of mass position damaging the ACS pointing accuracy. Although, a well-designed controller can suppress such disturbances quickly, the controller error pointing may be limited by the minimum time necessary to suppress such disturbances thus affecting the satellite attitude acquisition. As a result, the design of the satellite controller needs to explore the limits between the conflicting requirements of performance and robustness. This paper investigates the effects of the interaction between the liquid motion (slosh and the satellite dynamics in order to predict what the damage to the controller performance and robustness is. The fuel slosh dynamics is modelled by a pendulum which parameters are identified using the Kalman filter technique. This information is used to design the satellite controller by the linear quadratic regulator (LQR and linear quadratic Gaussian (LQG methods to perform a planar manoeuvre assuming thrusters are actuators.

  13. 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.

  14. 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.

  15. Approximations for inclusion of rotor lag dynamics in helicopter flight dynamics models

    Science.gov (United States)

    Mckillip, Robert, Jr.; Curtiss, Howard C., Jr.

    1991-01-01

    Approximate forms are suggested for augmenting linear rotor/body response models to include rotor lag dynamics. Use of an analytically linearized rotor/body model has shown that the primary effect comes from the additional angular rate contributions of the lag inertial response. Addition of lag dynamics may be made assuming these dynamics are represented by an isolated rotor with no shaft motion. Implications of such an approximation are indicated through comparison with flight test data and sensitivity of stability levels with body rate feedback.

  16. 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.

  17. Attitude Control Flight Experience: Coping with Solar Radiation and Ion Engines Leak Thrust in Hayabusa (MUSES-C)

    Science.gov (United States)

    Kawaguchi, Jun'ichiro; Kominato, Takashi; Shirakawa, Ken'ichi

    2007-01-01

    The paper presents the attitude reorientation taking the advantage of solar radiation pressure without use of any fuel aboard. The strategy had been adopted to make Hayabusa spacecraft keep pointed toward the Sun for several months, while spinning. The paper adds the above mentioned results reported in Sedona this February showing another challenge of combining ion engines propulsion tactically balanced with the solar radiation torque with no spin motion. The operation has been performed since this March for a half year successfully. The flight results are presented with the estimated solar array panel diffusion coefficient and the ion engine's swirl torque.

  18. Dynamically multiplexed ion mobility time-of-flight mass spectrometry.

    Science.gov (United States)

    Belov, Mikhail E; Clowers, Brian H; Prior, David C; Danielson, William F; Liyu, Andrei V; Petritis, Brianne O; Smith, Richard D

    2008-08-01

    Ion mobility spectrometry-time-of-flight mass spectrometry (IMS-TOFMS) has been increasingly used in analysis of complex biological samples. A major challenge is to transform IMS-TOFMS to a high-sensitivity, high-throughput platform, for example, for proteomics applications. In this work, we have developed and integrated three advanced technologies, including efficient ion accumulation in an ion funnel trap prior to IMS separation, multiplexing (MP) of ion packet introduction into the IMS drift tube, and signal detection with an analog-to-digital converter, into the IMS-TOFMS system for the high-throughput analysis of highly complex proteolytic digests of, for example, blood plasma. To better address variable sample complexity, we have developed and rigorously evaluated a novel dynamic MP approach that ensures correlation of the analyzer performance with an ion source function and provides the improved dynamic range and sensitivity throughout the experiment. The MP IMS-TOFMS instrument has been shown to reliably detect peptides at a concentration of 1 nM in the presence of a highly complex matrix, as well as to provide a 3 orders of magnitude dynamic range and a mass measurement accuracy of better than 5 ppm. When matched against human blood plasma database, the detected IMS-TOF features were found to yield approximately 700 unique peptide identifications at a false discovery rate (FDR) of approximately 7.5%. Accounting for IMS information gave rise to a projected FDR of approximately 4%. Signal reproducibility was found to be greater than 80%, while the variations in the number of unique peptide identifications were <15%. A single sample analysis was completed in 15 min that constitutes almost 1 order of magnitude improvement compared to a more conventional LC-MS approach. PMID:18582088

  19. In-flight attitude perturbances estimation: application to PLEIADES-HR satellites

    Science.gov (United States)

    Amberg, V.; Dechoz, C.; Bernard, L.; Greslou, D.; de Lussy, F.; Lebegue, L.

    2013-09-01

    This paper deals with the problem of retrieving attitude perturbances in the framework of the PLEIADES-HR optical satellites. Thus, two complementary methods are compared. The first one uses the high agility capacity of satellites to acquire stars in an inertial steering mode. The second method exploits the fact that multispectral CCD arrays are shifted in the telescope focal plane in the velocity direction: for a same ground point, the resulting images are not affected by the same attitude perturbances. The resulting misregistrations can be exploited to deduce information about the attitude platform. Both methods have been applied to PLEIADES-HR satellites, during commissioning period.

  20. The Dynamics of Miscible Fluids: A Space Flight Experiment (MIDAS)

    Science.gov (United States)

    Maxworthy, T.; Meiburg, E.; Balasubramaniam, R.; Rashidnia, N.; Lauver, R.

    2001-01-01

    We propose a space flight experiment to study the dynamics of miscible interfaces. A less viscous fluid displaces one of higher viscosity within a tube. The two fluids are miscible in all proportions. An intruding "finger" forms that occupies a fraction of the tube. As time progresses diffusion at the interface combined with flow induced straining between the two fluids modifies the concentration and velocity distributions within the whole tube. Also, under such circumstances it has been proposed that the interfacial stresses could depend on the local concentration gradients (Korteweg stresses) and that the divergence of the velocity need not be zero, even though the flow is incompressible. We have obtained reasonable agreement for the tip velocity between numerical simulations (that ignored the Korteweg stress and divergence effects) and physical experiments only at high Peelet Numbers. However at moderate to low Pe agreement was poor. As one possibility we attributed this lack of agreement to the disregard of these effects. We propose a space experiment to measure the finger shape, tip velocity, and the velocity and concentration fields. From intercomparisons between the experiment and the calculations we can then extract values for the coefficients of the Korteweg stress terms and confirm or deny the importance of these stresses.

  1. Optical feather and foil for shape and dynamic load sensing of critical flight surfaces

    Science.gov (United States)

    Black, Richard J.; Costa, Joannes M.; Faridian, Fereydoun; Moslehi, Behzad; Pakmehr, Mehrdad; Schlavin, Jon; Sotoudeh, Vahid; Zagrai, Andrei

    2014-04-01

    Future flight vehicles may comprise complex flight surfaces requiring coordinated in-situ sensing and actuation. Inspired by the complexity of the flight surfaces on the wings and tail of a bird, it is argued that increasing the number of interdependent flight surfaces from just a few, as is normal in an airplane, to many, as in the feathers of a bird, can significantly enlarge the flight envelope. To enable elements of an eco-inspired Dynamic Servo-Elastic (DSE) flight control system, IFOS is developing a multiple functionality-sensing element analogous to a feather, consisting of a very thin tube with optical fiber based strain sensors and algorithms for deducing the shape of the "feather" by measuring strain at multiple points. It is envisaged that the "feather" will act as a unit of sensing and/or actuation for establishing shape, position, static and dynamic loads on flight surfaces and in critical parts. Advanced sensing hardware and software control algorithms will enable the proposed DSE flight control concept. The hardware development involves an array of optical fiber based sensorized needle tubes for attachment to key parts for dynamic flight surface measurement. Once installed the optical fiber sensors, which can be interrogated over a wide frequency range, also allow damage detection and structural health monitoring.

  2. 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.

  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. Bifurcation Tools for Flight Dynamics Analysis and Control System Design Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Modern bifurcation analysis methods have been proposed for investigating flight dynamics and control system design in highly nonlinear regimes and also for the...

  5. Frequency-Domain Identification of XV-15 Tilt-Rotor Aircraft Dynamics in Hovering Flight

    Science.gov (United States)

    Tischler, Mark B.; Leung, Joseph G. M.; Dugan, Daniel C.

    1985-01-01

    Frequency-domain methods are used to identify the open-loop dynamics of the XV-15 tilt-rotor aircraft from flight tests. Piloting and data analysis techniques are presented to determine frequency response plots and equivalent transfer function models. The open-loop pitch and roll dynamics for the hover flight condition exhibit unstable low-frequency oscillations, whereas the dynamics in the remaining degrees of freedom are lightly damped and generally decoupled. Comparisons of XV-15 flight-test and simulator data are more favorable for high-frequency inputs (omega greater than 1.0 rad/sec) than low-frequency inputs. Time-domain comparisons of the extracted transfer functions with step response flight data are very favorable, even for large amplitude motions. The results presented in this paper demonstrate the utility of the frequency-domain techniques for dynamics identification and simulator fidelity studies.

  6. 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...

  7. Blowfly flight and optic flow I. Thorax kinematics and flight dynamics

    NARCIS (Netherlands)

    Schilstra, C; Van Hateren, JH

    1999-01-01

    The motion of the thorax of the blowfly Calliphora vicina was measured during cruising flight inside a cage measuring 40 cmx40 cmx40 cm, Sensor coils mounted on the thorax picked up externally generated magnetic fields and yielded measurements of the position and orientation of the thorax with a res

  8. Blowfly Flight and Optic Flow. I. Thorax Kinematics and Flight Dynamics

    NARCIS (Netherlands)

    Schilstra, C.; Hateren, J.H. van

    1999-01-01

    The motion of the thorax of the blowfly Calliphora vicina was measured during cruising flight inside a cage measuring 40cm×40cm×40 cm. Sensor coils mounted on the thorax picked up externally generated magnetic fields and yielded measurements of the position and orientation of the thorax with a resol

  9. Development of an Autonomous Flight Control System for Small Size Unmanned Helicopter Based on Dynamical Model

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    It is devoted to the development of an autonomous flight control system for small size unmanned helicopter based on dynamical model. At first, the mathematical model of a small size helicopter is described. After that simple but effective MTCV control algorithm was proposed. The whole flight control algorithm is composed of two parts:orientation controller based on the model for rotation dynamics and a robust position controller for a double integrator. The MTCV block is also used to achieve translation velocity control. To demonstrate the performance of the presented algorithm, simulation results and results achieved in real flight experiments were presented.

  10. Flight Dynamics Operations: Methods and Lessons Learned from Space Shuttle Orbit Operations

    Science.gov (United States)

    Cutri-Kohart, Rebecca M.

    2011-01-01

    The Flight Dynamics Officer is responsible for trajectory maintenance of the Space Shuttle. This paper will cover high level operational considerations, methodology, procedures, and lessons learned involved in performing the functions of orbit and rendezvous Flight Dynamics Officer and leading the team of flight dynamics specialists during different phases of flight. The primary functions that will be address are: onboard state vector maintenance, ground ephemeris maintenance, calculation of ground and spacecraft acquisitions, collision avoidance, burn targeting for the primary mission, rendezvous, deorbit and contingencies, separation sequences, emergency deorbit preparation, mass properties coordination, payload deployment planning, coordination with the International Space Station, and coordination with worldwide trajectory customers. Each of these tasks require the Flight Dynamics Officer to have cognizance of the current trajectory state as well as the impact of future events on the trajectory plan in order to properly analyze and react to real-time changes. Additionally, considerations are made to prepare flexible alternative trajectory plans in the case timeline changes or a systems failure impact the primary plan. The evolution of the methodology, procedures, and techniques used by the Flight Dynamics Officer to perform these tasks will be discussed. Particular attention will be given to how specific Space Shuttle mission and training simulation experiences, particularly off-nominal or unexpected events such as shortened mission durations, tank failures, contingency deorbit, navigation errors, conjunctions, and unexpected payload deployments, have influenced the operational procedures and training for performing Space Shuttle flight dynamics operations over the history of the program. These lessons learned can then be extended to future vehicle trajectory operations.

  11. An investigation into the flight dynamics of airships with application to the YEZ-2A

    OpenAIRE

    Gomes, S. B. V.

    1990-01-01

    In order to construct a flight dynamics computer simulation model of airship flight with a high degree of fidelity in the aerodynamic modelling, extensive wind tunnel testing was carried out. This was aimed at, first developing some specific airship wind tunnel testing techniques and then to obtain aerodynamic data for the YEZ-2A project airship being designed and built by Airship Industries for the US Navy. The wind tunnel testing techniques so developed insured a good matching between wind ...

  12. Robust bounded control for uncer tain flight dynamics using disturbance observer

    Institute of Scientific and Technical Information of China (English)

    Mou Chen; Bin Jiang

    2014-01-01

    The robust bounded flight control scheme is developed for the uncertain longitudinal flight dynamics of the fighter with con-trol input saturation invoking the backstepping technique. To en-hance the disturbance rejection ability of the robust flight control for fighters, the sliding mode disturbance observer is designed to esti-mate the compounded disturbance including the unknown external disturbance and the effect of the control input saturation. Based on the backstepping technique and the compounded disturbance estimated output, the robust bounded flight control scheme is pro-posed for the fighter with the unknown external disturbance and the control input saturation. The closed-loop system stability under the developed robust bounded flight control scheme is rigorously proved using the Lyapunov method and the uniformly asymptotical convergences of al closed-loop signals are guaranteed. Final y, simulation results are presented to show the effectiveness of the proposed robust bounded flight control scheme for the uncertain longitudinal flight dynamics of the fighter.

  13. Orbital dynamics and equilibrium points around an asteroid with gravitational orbit-attitude coupling perturbation

    Science.gov (United States)

    Wang, Yue; Xu, Shijie

    2016-07-01

    The strongly perturbed dynamical environment near asteroids has been a great challenge for the mission design. Besides the non-spherical gravity, solar radiation pressure, and solar tide, the orbital motion actually suffers from another perturbation caused by the gravitational orbit-attitude coupling of the spacecraft. This gravitational orbit-attitude coupling perturbation (GOACP) has its origin in the fact that the gravity acting on a non-spherical extended body, the real case of the spacecraft, is actually different from that acting on a point mass, the approximation of the spacecraft in the orbital dynamics. We intend to take into account GOACP besides the non-spherical gravity to improve the previous close-proximity orbital dynamics. GOACP depends on the spacecraft attitude, which is assumed to be controlled ideally with respect to the asteroid in this study. Then, we focus on the orbital motion perturbed by the non-spherical gravity and GOACP with the given attitude. This new orbital model can be called the attitude-restricted orbital dynamics, where restricted means that the orbital motion is studied as a restricted problem at a given attitude. In the present paper, equilibrium points of the attitude-restricted orbital dynamics in the second degree and order gravity field of a uniformly rotating asteroid are investigated. Two kinds of equilibria are obtained: on and off the asteroid equatorial principal axis. These equilibria are different from and more diverse than those in the classical orbital dynamics without GOACP. In the case of a large spacecraft, the off-axis equilibrium points can exist at an arbitrary longitude in the equatorial plane. These results are useful for close-proximity operations, such as the asteroid body-fixed hovering.

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

    DEFF Research Database (Denmark)

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

    1999-01-01

    The second qualification flight of Ariane 5 was launched from the European Space Port in French Guiana on October 30, 1997. It carried on board a small technology demonstration satellite dubbed TeamSat into which five experiments, proposed by various universities and research institutions, were...

  15. 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.

  16. 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

  17. Conflict probability evaluation taking into account the dynamics and correlation of aircraft flight process

    Directory of Open Access Journals (Sweden)

    В.М. Васильєв

    2004-04-01

    Full Text Available  The probability method of conflict detection for collision avoidance systems is offered enabling to take into account the features of stochastic dynamics of aircraft flight process and correlation of a trajectory with time. The general approach to a solution of a problem is presented and the analytical solution on a concrete example is demonstrated.

  18. Non-linear Flight Dynamics at High Angles of Attack

    DEFF Research Database (Denmark)

    Granasy, P.; Sørensen, C.B.; Mosekilde, Erik;

    1998-01-01

    The methods of nonlinear dynamics are applied to the longitudinal motion of a vectored thrust aircraft, in particular the behavior at high angles of attack. Our model contains analytic nonlinear aerodynamical coefficients based on NASA windtunnel experiments on the F-18 high-alpha research vehicl...

  19. Aperiodic dynamics in a deterministic model of attitude formation in social groups

    CERN Document Server

    Ward, Jonathan

    2013-01-01

    Homophily and social influence are the fundamental mechanisms that drive the evolution of attitudes, beliefs and behaviour within social groups. Homophily relates the similarity between pairs of individuals' attitudinal states to their frequency of interaction, and hence structural tie strength, while social influence causes the convergence of individuals' states during interaction. Building on these basic elements, we propose a new mathematical modelling framework to describe the evolution of attitudes within a group of interacting agents. Specifically, our model describes sub-conscious attitudes that have an activator-inhibitor relationship. We consider a homogeneous population using a deterministic, continuous-time dynamical system. Surprisingly, the combined effects of homophily and social influence do not necessarily lead to group consensus or global monoculture. We observe that sub-group formation and polarisation-like effects may be transient, the long-time dynamics being quasi-periodic with sensitive ...

  20. A wake bending unsteady dynamic inflow model of tiltrotor in conversion flight of tiltrotor aircraft

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The aerodynamics, dynamic responses and aeroelasticity of tiltrotor aircraft in the tilting of rotor i.e. in conversion flight are extraordinarily complicated. The traditional quasi-steady assumption model can not reflect the unsteady aerodynamic problems in the tilting of rotor. The CFD method based on the vortex theory can get better results, but it consumes a lot of computing resources. In this paper, a wake bending dynamic inflow model of tilting rotor was established firstly based on the Peters-He dynamic inflow model used in helicopter. Then combining with the ONERA unsteady aerodynamic model, a wake bending unsteady dynamic inflow model of tilting rotor in conversion flight of tiltrotor aircraft was established. The wake bending unsteady dynamic inflow model of tilting rotor was verified by using the experimental data of an isolated rotor model in large angle pitching up maneuver and was used to calculate the dynamic responses of tilting rotor in conversion flight of a tiltrotor aircraft model. The calculated results were analyzed to be physically reasonable.

  1. 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.

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

    Science.gov (United States)

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

    2014-01-01

    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. PMID:25530662

  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. 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...

  5. Attitude dynamics and control of spacecraft using geomagnetic Lorentz force

    International Nuclear Information System (INIS)

    Attitude stabilization of a charged rigid spacecraft in Low Earth Orbit using torques due to Lorentz force in pitch and roll directions is considered. A spacecraft that generates an electrostatic charge on its surface in the Earth's magnetic field will be subject to perturbations from the Lorentz force. The Lorentz force acting on an electrostatically charged spacecraft may provide a useful thrust for controlling a spacecraft's orientation. We assume that the spacecraft is moving in the Earth's magnetic field in an elliptical orbit under the effects of gravitational, geomagnetic and Lorentz torques. The magnetic field of the Earth is modeled as a non-tilted dipole. A model incorporating all Lorentz torques as a function of orbital elements has been developed on the basis of electric and magnetic fields. The stability of the spacecraft orientation is investigated both analytically and numerically. The existence and stability of equilibrium positions is investigated for different values of the charge to mass ratio (α*). Stable orbits are identified for various values of α*. The main parameters for stabilization of the spacecraft are α* and the difference between the components of the moment of inertia for the spacecraft. (research papers)

  6. Wing wear reduces bumblebee flight performance in a dynamic obstacle course.

    Science.gov (United States)

    Mountcastle, Andrew M; Alexander, Teressa M; Switzer, Callin M; Combes, Stacey A

    2016-06-01

    Previous work has shown that wing wear increases mortality in bumblebees. Although a proximate mechanism for this phenomenon has remained elusive, a leading hypothesis is that wing wear increases predation risk by reducing flight manoeuvrability. We tested the effects of simulated wing wear on flight manoeuvrability in Bombus impatiens bumblebees using a dynamic obstacle course designed to push bees towards their performance limits. We found that removing 22% wing area from the tips of both forewings (symmetric wear) caused a 9% reduction in peak acceleration during manoeuvring flight, while performing the same manipulation on only one wing (asymmetric wear) did not significantly reduce maximum acceleration. The rate at which bees collided with obstacles was correlated with body length across all treatments, but wing wear did not increase collision rate, possibly because shorter wingspans allow more room for bees to manoeuvre. This study presents a novel method for exploring extreme flight manoeuvres in flying insects, eliciting peak accelerations that exceed those measured during flight through a stationary obstacle course. If escape from aerial predation is constrained by acceleration capacity, then our results offer a potential explanation for the observed increase in bumblebee mortality with wing wear.

  7. Wing wear reduces bumblebee flight performance in a dynamic obstacle course.

    Science.gov (United States)

    Mountcastle, Andrew M; Alexander, Teressa M; Switzer, Callin M; Combes, Stacey A

    2016-06-01

    Previous work has shown that wing wear increases mortality in bumblebees. Although a proximate mechanism for this phenomenon has remained elusive, a leading hypothesis is that wing wear increases predation risk by reducing flight manoeuvrability. We tested the effects of simulated wing wear on flight manoeuvrability in Bombus impatiens bumblebees using a dynamic obstacle course designed to push bees towards their performance limits. We found that removing 22% wing area from the tips of both forewings (symmetric wear) caused a 9% reduction in peak acceleration during manoeuvring flight, while performing the same manipulation on only one wing (asymmetric wear) did not significantly reduce maximum acceleration. The rate at which bees collided with obstacles was correlated with body length across all treatments, but wing wear did not increase collision rate, possibly because shorter wingspans allow more room for bees to manoeuvre. This study presents a novel method for exploring extreme flight manoeuvres in flying insects, eliciting peak accelerations that exceed those measured during flight through a stationary obstacle course. If escape from aerial predation is constrained by acceleration capacity, then our results offer a potential explanation for the observed increase in bumblebee mortality with wing wear. PMID:27303054

  8. Attitude Dynamics of a Spinning Rocket with Internal Fluid Whirling Motion

    Directory of Open Access Journals (Sweden)

    Marius Ionut MARMUREANU

    2014-06-01

    Full Text Available This paper evaluates the impact that helical motion of fluid products of combustion within the combustion chamber of a rocket can have on the attitude dynamics of rocket systems. By developing the study presented by Sookgaew (2004, we determined the configuration of the Coriolis moment components, which catch the impact of the combustion product’s whirling motion, for the radial and centripetal propellant burn pattern specific to S-5M and S-5K solid rocket motors. We continue the investigation of the effects of internal whirling motion of fluid products of combustion on the attitude behavior of variable mass systems of the rocket type by examining the spin motion and transverse attitude motion of such systems. The results obtained show that internal fluid whirling motion can cause appreciable deviations in spin rate predictions, and also affects the frequencies of the transverse angular velocity components.

  9. Integrating Flight Dynamics & Control Analysis and Simulation in Rotorcraft Conceptual Design

    Science.gov (United States)

    Lawrence, Ben; Berger, Tom; Tischler, Mark B.; Theodore, Colin R; Elmore, Josh; Gallaher, Andrew; Tobias, Eric L.

    2016-01-01

    The development of a toolset, SIMPLI-FLYD ('SIMPLIfied FLight dynamics for conceptual Design') is described. SIMPLI-FLYD is a collection of tools that perform flight dynamics and control modeling and analysis of rotorcraft conceptual designs including a capability to evaluate the designs in an X-Plane-based real-time simulation. The establishment of this framework is now facilitating the exploration of this new capability, in terms of modeling fidelity and data requirements, and the investigation of which stability and control and handling qualities requirements are appropriate for conceptual design. Illustrative design variation studies for single main rotor and tiltrotor vehicle configurations show sensitivity of the stability and control characteristics and an approach to highlight potential weight savings by identifying over-design.

  10. Real-Time Dynamic Modeling - Data Information Requirements and Flight Test Results

    Science.gov (United States)

    Morelli, Eugene A.; Smith, Mark S.

    2010-01-01

    Practical aspects of identifying dynamic models for aircraft in real time were studied. Topics include formulation of an equation-error method in the frequency domain to estimate non-dimensional stability and control derivatives in real time, data information content for accurate modeling results, and data information management techniques such as data forgetting, incorporating prior information, and optimized excitation. Real-time dynamic modeling was applied to simulation data and flight test data from a modified F-15B fighter aircraft, and to operational flight data from a subscale jet transport aircraft. Estimated parameter standard errors, prediction cases, and comparisons with results from a batch output-error method in the time domain were used to demonstrate the accuracy of the identified real-time models.

  11. Robust Adaptive Geometric Tracking Controls on SO(3) with an Application to the Attitude Dynamics of a Quadrotor UAV

    CERN Document Server

    Lee, Taeyoung

    2011-01-01

    This paper provides new results for a robust adaptive tracking control of the attitude dynamics of a rigid body. Both of the attitude dynamics and the proposed control system are globally expressed on the special orthogonal group, to avoid complexities and ambiguities associated with other attitude representations such as Euler angles or quaternions. By designing an adaptive law for the inertia matrix of a rigid body, the proposed control system can asymptotically follow an attitude command without the knowledge of the inertia matrix, and it is extended to guarantee boundedness of tracking errors in the presence of unstructured disturbances. These are illustrated by numerical examples and experiments for the attitude dynamics of a quadrotor UAV.

  12. Development of a simulation tool for flight dynamics and control investigations of articulated vtol unmanned aircraft

    OpenAIRE

    Saghafi, F.

    1996-01-01

    A simulation tool for flight dynamics and control investigations of three different Vertical Take Off and Landing (VTOL) unmanned aircraft configurations has been developed. A control concept has been proposed in order to take advantage of the fast response characteristics of the ordinary small engine/propeller propulsion systems in such aircraft, as well as replacing the complex rotors used previously in VTOL concepts for small unmanned aircraft. The simulation model has been ...

  13. A multibody approach for 6-DOF flight dynamics and stability analysis of the hawkmoth Manduca sexta.

    Science.gov (United States)

    Kim, Joong-Kwan; Han, Jae-Hung

    2014-03-01

    This paper investigates the six degrees of freedom (6-DOF) flight dynamics and stability of the hawkmoth Manduca sexta using a multibody dynamics approach that encompasses the effects of the time varying inertia tensor of all the body segments including two wings. The quasi-steady translational and unsteady rotational aerodynamics of the flapping wings are modeled with the blade element theory with aerodynamic coefficients derived from relevant experimental studies. The aerodynamics is given instantaneously at each integration time step without wingbeat-cycle-averaging. With the multibody dynamic model and the aerodynamic model for the hawkmoth, a direct time integration of the fully coupled 6-DOF nonlinear multibody dynamics equations of motion is performed. First, the passive damping magnitude of each single DOF is quantitatively examined with the measure of the time taken to half the initial velocity (thalf). The results show that the sideslip translation is less damped approximately three times than the other two translational DOFs, and the pitch rotation is less damped approximately five times than the other two rotational DOFs; each DOF has the value of (unit in wingbeat strokes): thalf,forward/backward = 7.10, thalf,sideslip = 17.95, thalf,ascending = 7.13, thalf,descending = 5.77, thalf,roll = 0.68, thalf,pitch = 2.39, and thalf,yaw = 0.25. Second, the natural modes of motion, with the hovering flight as a reference equilibrium condition, are examined by analyzing fully coupled 6-DOF dynamic responses induced by multiple sets of force and moment disturbance combinations. The given disturbance combinations are set to excite the dynamic modes identified in relevant eigenmode analysis studies. The 6-DOF dynamic responses obtained from this study are compared with eigenmode analysis results in the relevant studies. The longitudinal modes of motion showed dynamic modal characteristics similar to the eigenmode analysis results from the relevant literature

  14. Computational Fluid Dynamics Analysis Success Stories of X-Plane Design to Flight Test

    Science.gov (United States)

    Cosentino, Gary B.

    2008-01-01

    Examples of the design and flight test of three true X-planes are described, particularly X-plane design techniques that relied heavily on computational fluid dynamics(CFD) analysis. Three examples are presented: the X-36 Tailless Fighter Agility Research Aircraft, the X-45A Unmanned Combat Air Vehicle, and the X-48B Blended Wing Body Demonstrator Aircraft. An overview is presented of the uses of CFD analysis, comparison and contrast with wind tunnel testing, and information derived from CFD analysis that directly related to successful flight test. Lessons learned on the proper and improper application of CFD analysis are presented. Highlights of the flight-test results of the three example X-planes are presented. This report discusses developing an aircraft shape from early concept and three-dimensional modeling through CFD analysis, wind tunnel testing, further refined CFD analysis, and, finally, flight. An overview of the areas in which CFD analysis does and does not perform well during this process is presented. How wind tunnel testing complements, calibrates, and verifies CFD analysis is discussed. Lessons learned revealing circumstances under which CFD analysis results can be misleading are given. Strengths and weaknesses of the various flow solvers, including panel methods, Euler, and Navier-Stokes techniques, are discussed.

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

    Science.gov (United States)

    Xu, Na; Sun, Mao

    2014-09-01

    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.

  16. Strategic flight assignment approach based on multi-objective parallel evolution algorithm with dynamic migration interval

    Directory of Open Access Journals (Sweden)

    Zhang Xuejun

    2015-04-01

    Full Text Available The continuous growth of air traffic has led to acute airspace congestion and severe delays, which threatens operation safety and cause enormous economic loss. Flight assignment is an economical and effective strategic plan to reduce the flight delay and airspace congestion by reasonably regulating the air traffic flow of China. However, it is a large-scale combinatorial optimization problem which is difficult to solve. In order to improve the quality of solutions, an effective multi-objective parallel evolution algorithm (MPEA framework with dynamic migration interval strategy is presented in this work. Firstly, multiple evolution populations are constructed to solve the problem simultaneously to enhance the optimization capability. Then a new strategy is proposed to dynamically change the migration interval among different evolution populations to improve the efficiency of the cooperation of populations. Finally, the cooperative co-evolution (CC algorithm combined with non-dominated sorting genetic algorithm II (NSGA-II is introduced for each population. Empirical studies using the real air traffic data of the Chinese air route network and daily flight plans show that our method outperforms the existing approaches, multi-objective genetic algorithm (MOGA, multi-objective evolutionary algorithm based on decomposition (MOEA/D, CC-based multi-objective algorithm (CCMA as well as other two MPEAs with different migration interval strategies.

  17. Research on Acceleration Disturbance Suppression for Dynamic Detection of Level Attitude

    Science.gov (United States)

    Tan, Linxia; Zhang, Fuxue

    The paper presents a new method to eliminate acceleration disturbance in level attitude measurement and control of moving carrier. Output signals of micro-machined inclinometer and gyroscope are analyzed in different states of moving carrier by experimental simulation, results show that gyroscope almost keeps the zero output voltage while inclinometer outputs in significant fluctuations. With the analysis results, a new method on acceleration disturbance suppression is developed base on a combination of inclinometers and gyroscopes, which includes establishment and derivation of its mathematical model and implementation, and an algorithm software design. Finally, tests to the acceleration disturbance suppression effect are demonstrated in line motion, line vibration, angular motion and angular motion plus pitch swing. Experimental results show that the method achieves its expected effect. The inertial system constitutes of inclinometers and gyros interacting with acceleration disturbance suppression method can dynamic detect the level attitude of moving carrier.

  18. Dynamic Flight Stability of a Model Hoverfly in Inclined-Stroke-Plane Hovering

    Institute of Scientific and Technical Information of China (English)

    Xiaolei Mou; Mao Sun

    2012-01-01

    Most hovering insects flap their wings in a horizontal plane,called ‘normal hovering'.But some of the best hoverers,e.g.true hoverflies,hover with an inclined stroke plane.In the present paper,the longitudinal dynamic flight stability of a model hoverfly in inclined-stroke-plane hovering was studied.Computational fluid dynamics was used to compute the aerodynamic derivatives and the eigenvalue and eigenvector analysis was used to solve the equations of motion.The primary findings are as follows.(1) For inclined-stroke-plane hovering,the same three natural modes of motion as those for normal hovering were identified:one unstable oscillatory mode,one stable fast subsidence mode,and one stable slow subsidence mode.The unstable oscillatory mode and the fast subsidence mode mainly have horizontal translation and pitch rotation,and the slow subsidence mode mainly has vertical translation.(2) Because of the existence of the unstable oscillatory mode,inclined-stroke-plane hovering flight is not stable.(3) Although there are large differences in stroke plane and body orientations between the inclined-stroke-plane hovering and normal hovering,the relative position between the mean center of pressure and center of mass for these two cases is not very different,resulting in similar stability derivatives,hence similar dynamic stability properties for these two types of hovering.

  19. Investigation of the Effectiveness of Dynamic Seat in a Black Hawk Flight Simulation

    Science.gov (United States)

    Chung, William W. Y.; Bengford, Norm; Perry, Chuck; Nicholson, Bob; Wilkinson, Colin

    2001-01-01

    Low cost alternatives have been sought to provide motion cues in ground-based flight simulators to meet mission objectives. The ability to provide high frequency vibrations makes the dynamic seat attractive to helicopter training applications. Previous studies have found that dynamic seat does enhance the realism of the cockpit and affect pilots' workload. This investigation, conducted under the auspices of the Joint Shipboard Helicopter Integration Process (JSHIP), is using a three degree-of-freedom dynamic seat, i.e., heave, surge, and sway, with limited travels in a research simulator configured as a UH-60 Black Hawk at NASA Ames Research Center. The seat's effectiveness is studied using hover, landing, pirouette, bob-up/bob-down, sidestep, and acceleration/deceleration maneuvers. Seat commands consist of constant vibrations in heave and sway which provide the fundamental vibratory cues. Pilot station accelerations and collective controls provide onset and sustained commands. In addition, transient effects due to translational-lift, collective; and normal acceleration are produced by regulating the magnitude and frequency that depend on the rotor rpm. Results are compared to flight test data and two other ground-based motion systems configurations, i.e., a motion condition with very large motion travels and a motion condition that is comparable with commercial simulator travels. Both subjective and objective data will be analyzed to determine the significance of the motion cueing effect in each system for selected maneuvers.

  20. 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.

  1. 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.

  2. 微小卫星低可观测外形飞行姿态规划%Flight Attitude Planning for Low Observable Micro-satellite Shields

    Institute of Scientific and Technical Information of China (English)

    苏抗; 周建江

    2011-01-01

    为提高在轨微小卫星的使用效能及生存能力,提出一种微小卫星低可观测外形飞行姿态规划算法.根据微小卫星雷达散射截面(RCS)、轨道及雷达威胁特性,建立了可进行长时间内最佳飞行姿态规划的数学模型,设计了低计算复杂度的链表式个体结构及进化规划策略,并实现了算法对高威胁区优化规划的能力.同时,算法低迭代步长下的快速收敛特性以及进化中规划精度及计算量可变的设计,也使其可灵活应用于不同的规划任务.仿真结果表明,算法可有效降低S波段及甚高频(VHF)波段雷达对微小卫星的威胁性,满足微小卫星低可观测外形飞行姿态规划的需求.%A flight attitude planning algorithm is developed for Iow observable micro-satellite shields to enhance the on-orbit satellite's survivability and operational effectiveness.According to the micro-satellite's radar cross section (RCS), its orbit and radar threat characteristics, a planning mathematical model is established to find the optimal flight attitude in a long planning period of time.A novel linked-list individual structure and an evolutionary planning strategy are defined to reduce the planning computational complexity, and a special planning method is designed to enhance the planning performance when the micro-satellite travels through a high threat zone.At the same time, the algorithm converges quickly with limited iterative steps, and the planning precision and computational load can be adaptively controlled during the planning.These features make the planning algorithm available for different applications.In the simulation, the algorithm reduces the micro-satellite' s S-band and very high frequency (VHF)-band radar threat level obviously, and meets the needs of the low observable micro-satellite shield flight attitude planning.

  3. Optical Feather and Foil for Shape and Dynamic Load Sensing of Critical Flight Surfaces Project

    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...

  4. Rotor dynamic state and parameter identification from simulated forward flight transients, part 1

    Science.gov (United States)

    Hohenemser, K. H.; Banerjee, D.; Yin, S. K.

    1976-01-01

    State and parameter identifications from simulated forward flight blade flapping measurements are presented. The transients were excited by progressing cyclic pitch stirring or by hub stirring with constant stirring acceleration. Rotor dynamic inflow models of varying degree of sophistication were used from a one parameter inflow model (equivalent Lock number) to an eight parameter inflow model. The maximum likelihood method with assumed fixed measurement error covariance matrix was applied. The rotor system equations for both fixed hub and tilting hub are given. The identified models were verified by comparing true responses with predicted responses. An optimum utilization of the simulated measurement data can be defined. From the numerical results it can be anticipated that brief periods of either accelerated cyclic pitch stirring or of hub stirring are sufficient to extract with adequate accuracy up to 8 rotor dynamic inflow parameters plus the blade Lock number from the transients.

  5. Dynamics of energy substrates in the haemolymph of Locusta migratoria during flight

    OpenAIRE

    Van der Horst, D J; Houben, N.M.D.; Beenakkers, A.M.Th.

    1980-01-01

    In the two-fuel system for flight of the migratory locust, the haemolymph carbohydrate concentration falls during flight periods of up to 1 hr, the decrease being greater in case the pre-flight carbohydrate level is higher. The increase in the lipid concentration from the onset of flight is virtually independent of the initial lipid concentration. Flight intensity affects these changes in substrate concentrations: the carbohydrate level decreases more rapidly if flight speed is higher, wherea...

  6. 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

  7. Spacecraft attitude control systems with dynamic methods and structures for processing star tracker signals

    Science.gov (United States)

    Liu, Yong (Inventor); Wu, Yeong-Wei Andy (Inventor); Li, Rongsheng (Inventor)

    2001-01-01

    Methods are provided for dynamically processing successively-generated star tracker data frames and associated valid flags to generate processed star tracker signals that have reduced noise and a probability greater than a selected probability P.sub.slctd of being valid. These methods maintain accurate spacecraft attitude control in the presence of spurious inputs (e.g., impinging protons) that corrupt collected charges in spacecraft star trackers. The methods of the invention enhance the probability of generating valid star tracker signals because they respond to a current frame probability P.sub.frm by dynamically selecting the largest valid frame combination whose combination probability P.sub.cmb satisfies a selected probability P.sub.slctd. Noise is thus reduced while the probability of finding a valid frame combination is enhanced. Spacecraft structures are also provided for practicing the methods of the invention.

  8. Dynamics of energy substrates in the haemolymph of Locusta migratoria during flight

    NARCIS (Netherlands)

    Horst, D.J. van der; Houben, N.M.D.; Beenakkers, A.M.Th.

    1980-01-01

    In the two-fuel system for flight of the migratory locust, the haemolymph carbohydrate concentration falls during flight periods of up to 1 hr, the decrease being greater in case the pre-flight carbohydrate level is higher. The increase in the lipid concentration from the onset of flight is virtuall

  9. 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.

  10. An exploratory investigation of the flight dynamics effects of rotor rpm variations and rotor state feedback in hover

    Science.gov (United States)

    Chen, Robert T. N.

    1992-01-01

    This paper presents the results of an analytical study conducted to investigate airframe/engine interface dynamics, and the influence of rotor speed variations on the flight dynamics of the helicopter in hover, and to explore the potential benefits of using rotor states as additional feedback signals in the flight control system. The analytical investigation required the development of a parametric high-order helicopter hover model, which included heave/yaw body motion, the rotor speed degree of freedom, rotor blade motion in flapping and lead-lag, inflow dynamics, a drive train model with a flexible rotor shaft, and an engine/rpm governor. First, the model was used to gain insight into the engine/drive train/rotor system dynamics and to obtain an improved simple formula for easy estimation of the dominant first torsional mode, which is important in the dynamic integration of the engine and airframe system. Then, a linearized version of the model was used to investigate the effects of rotor speed variations and rotor state feedback on helicopter flight dynamics. Results show that, by including rotor speed variations, the effective vertical damping decreases significantly from that calculated with a constant speed assumption, thereby providing a better correlation with flight test data. Higher closed-loop bandwidths appear to be more readily achievable with rotor state feedback. The results also indicate that both aircraft and rotor flapping responses to gust disturbance are significantly attenuated when rotor state feedback is used.

  11. Bombs, flyin' high. In-flight dynamics of volcanic bombs from Strombolian to Vulcanian eruptions.

    Science.gov (United States)

    Taddeucci, Jacopo; Alatorre, Miguel; Cruz Vázquez, Omar; Del Bello, Elisabetta; Ricci, Tullio; Scarlato, Piergiorgio; Palladino, Danilo

    2016-04-01

    Bomb-sized (larger than 64 mm) pyroclasts are a common product of explosive eruptions and a considerable source of hazard, both from directly impacting on people and properties and from wildfires associated with their landing in vegetated areas. The dispersal of bombs is mostly modeled as purely ballistic trajectories controlled by gravity and drag forces associated with still air, and only recently other effects, such as the influence of eruption dynamics, the gas expansion, and in-flight collisions, are starting to be quantified both numerically and observationally. By using high-speed imaging of explosive volcanic eruptions here we attempt to calculate the drag coefficient of free-flying volcanic bombs during an eruption and at the same time we document a wide range of in-flight processes affecting bomb trajectories and introducing deviations from purely ballistic emplacement. High-speed (500 frames per second) videos of explosions at Stromboli and Etna (Italy), Fuego (Gatemala), Sakurajima (Japan), Yasur (Vanuatu), and Batu Tara (Indonesia) volcanoes provide a large assortment of free-flying bombs spanning Strombolian to Vulcanian source eruptions, basaltic to andesitic composition, centimeters to meters in size, and 10 to 300 m/s in fly velocity. By tracking the bombs during their flying trajectories we were able to: 1) measure their size, shape, and vertical component of velocity and related changes over time; and 2) measure the different interactions with the atmosphere and with other bombs. Quantitatively, these data allow us to provide the first direct measurement of the aerodynamic behavior and drag coefficient of volcanic bombs while settling, also including the effect of bomb rotation and changes in bomb shape and frontal section. We also show how our observations have the potential to parameterize a number of previously hypothesized and /or described but yet unquantified processes, including in-flight rotation, deformation, fragmentation, agglutination

  12. 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.

  13. Encrypted Three-dimensional Dynamic Imaging using Snapshot Time-of-flight Compressed Ultrafast Photography

    Science.gov (United States)

    Liang, Jinyang; Gao, Liang; Hai, Pengfei; Li, Chiye; Wang, Lihong V.

    2015-10-01

    Compressed ultrafast photography (CUP), a computational imaging technique, is synchronized with short-pulsed laser illumination to enable dynamic three-dimensional (3D) imaging. By leveraging the time-of-flight (ToF) information of pulsed light backscattered by the object, ToF-CUP can reconstruct a volumetric image from a single camera snapshot. In addition, the approach unites the encryption of depth data with the compressed acquisition of 3D data in a single snapshot measurement, thereby allowing efficient and secure data storage and transmission. We demonstrated high-speed 3D videography of moving objects at up to 75 volumes per second. The ToF-CUP camera was applied to track the 3D position of a live comet goldfish. We have also imaged a moving object obscured by a scattering medium.

  14. Encrypted Three-dimensional Dynamic Imaging using Snapshot Time-of-flight Compressed Ultrafast Photography.

    Science.gov (United States)

    Liang, Jinyang; Gao, Liang; Hai, Pengfei; Li, Chiye; Wang, Lihong V

    2015-10-27

    Compressed ultrafast photography (CUP), a computational imaging technique, is synchronized with short-pulsed laser illumination to enable dynamic three-dimensional (3D) imaging. By leveraging the time-of-flight (ToF) information of pulsed light backscattered by the object, ToF-CUP can reconstruct a volumetric image from a single camera snapshot. In addition, the approach unites the encryption of depth data with the compressed acquisition of 3D data in a single snapshot measurement, thereby allowing efficient and secure data storage and transmission. We demonstrated high-speed 3D videography of moving objects at up to 75 volumes per second. The ToF-CUP camera was applied to track the 3D position of a live comet goldfish. We have also imaged a moving object obscured by a scattering medium.

  15. A Flight Dynamics Model for a Multi-Actuated Flexible Rocket Vehicle

    Science.gov (United States)

    Orr, Jeb S.

    2011-01-01

    A comprehensive set of motion equations for a multi-actuated flight vehicle is presented. The dynamics are derived from a vector approach that generalizes the classical linear perturbation equations for flexible launch vehicles into a coupled three-dimensional model. The effects of nozzle and aerosurface inertial coupling, sloshing propellant, and elasticity are incorporated without restrictions on the position, orientation, or number of model elements. The present formulation is well suited to matrix implementation for large-scale linear stability and sensitivity analysis and is also shown to be extensible to nonlinear time-domain simulation through the application of a special form of Lagrange s equations in quasi-coordinates. The model is validated through frequency-domain response comparison with a high-fidelity planar implementation.

  16. [Dynamics of the body liquids and composition in long-duration space flight (bio-impedance analysis)].

    Science.gov (United States)

    Noskov, V B; Nichiporuk, I A; Grigor'ev, A I

    2007-01-01

    Bio-impedancemetiy was used to study dynamics of the human hydration status and body composition aboard the International space station (ISS). Body liquids in 12 Russian crewmembers were found reduced in different periods of space flight: the total, intra- and extracellular liquid volumes became less by 5.2 to 10.4% on the group average as compared with baseline values. In-flight changes in body composition also displayed a consistent pattern. While the lean mass loss was insignificant averaging 1.9-4.0%, the fatty mass gain averaged 4.6 to 8.2% in the initial three months on flight. We conclude that the human body hydration status falls along with the muscular mass reduction and fatty mass gain during long-duration space flight.

  17. 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.

  18. Hovering and forward flight of the hawkmoth Manduca sexta: trim search and 6-DOF dynamic stability characterization.

    Science.gov (United States)

    Kim, Joong-Kwan; Han, Jong-Seob; Lee, Jun-Seong; Han, Jae-Hung

    2015-09-28

    We show that the forward flight speed affects the stability characteristics of the longitudinal and lateral dynamics of a flying hawkmoth; dynamic modal structures of both the planes of motion are altered due to variations in the stability derivatives. The forward flight speed u e is changed from 0.00 to 1.00 m s(-1) with an increment of 0.25 m s(-1). (The equivalent advance ratio is 0.00 to 0.38; the advance ratio is the ratio of the forward flight speed to the average wing tip speed.) As the flight speed increases, for the longitudinal dynamics, an unstable oscillatory mode becomes more unstable. Also, we show that the up/down (w(b)) dynamics become more significant at a faster flight speed due to the prominent increase in the stability derivative Z(u) (up/down force due to the forward/backward velocity). For the lateral dynamics, the decrease in the stability derivative L(v) (roll moment due to side slip velocity) at a faster flight speed affects a slightly damped stable oscillatory mode, causing it to become more stable; however, the t(half) (the time taken to reach half the amplitude) of this slightly damped stable oscillatory mode remains relatively long (∼12T at u(e) = 1 m s(-1); T is wingbeat period) compared to the other modes of motion, meaning that this mode represents the most vulnerable dynamics among the lateral dynamics at all flight speeds. To obtain the stability derivatives, trim conditions for linearization are numerically searched to find the exact trim trajectory and wing kinematics using an algorithm that uses the gradient information of a control effectiveness matrix and fully coupled six-degrees of freedom nonlinear multibody equations of motion. With this algorithm, trim conditions that consider the coupling between the dynamics and aerodynamics can be obtained. The body and wing morphology, and the wing kinematics used in this study are based on actual measurement data from the relevant literature. The aerodynamic model of the flapping

  19. Hovering and forward flight of the hawkmoth Manduca sexta: trim search and 6-DOF dynamic stability characterization.

    Science.gov (United States)

    Kim, Joong-Kwan; Han, Jong-Seob; Lee, Jun-Seong; Han, Jae-Hung

    2015-10-01

    We show that the forward flight speed affects the stability characteristics of the longitudinal and lateral dynamics of a flying hawkmoth; dynamic modal structures of both the planes of motion are altered due to variations in the stability derivatives. The forward flight speed u e is changed from 0.00 to 1.00 m s(-1) with an increment of 0.25 m s(-1). (The equivalent advance ratio is 0.00 to 0.38; the advance ratio is the ratio of the forward flight speed to the average wing tip speed.) As the flight speed increases, for the longitudinal dynamics, an unstable oscillatory mode becomes more unstable. Also, we show that the up/down (w(b)) dynamics become more significant at a faster flight speed due to the prominent increase in the stability derivative Z(u) (up/down force due to the forward/backward velocity). For the lateral dynamics, the decrease in the stability derivative L(v) (roll moment due to side slip velocity) at a faster flight speed affects a slightly damped stable oscillatory mode, causing it to become more stable; however, the t(half) (the time taken to reach half the amplitude) of this slightly damped stable oscillatory mode remains relatively long (∼12T at u(e) = 1 m s(-1); T is wingbeat period) compared to the other modes of motion, meaning that this mode represents the most vulnerable dynamics among the lateral dynamics at all flight speeds. To obtain the stability derivatives, trim conditions for linearization are numerically searched to find the exact trim trajectory and wing kinematics using an algorithm that uses the gradient information of a control effectiveness matrix and fully coupled six-degrees of freedom nonlinear multibody equations of motion. With this algorithm, trim conditions that consider the coupling between the dynamics and aerodynamics can be obtained. The body and wing morphology, and the wing kinematics used in this study are based on actual measurement data from the relevant literature. The aerodynamic model of the flapping

  20. NASA/Army Rotorcraft Technology. Volume 2: Materials and Structures, Propulsion and Drive Systems, Flight Dynamics and Control, and Acoustics

    Science.gov (United States)

    1988-01-01

    The Conference Proceedings is a compilation of over 30 technical papers presented which report on the advances in rotorcraft technical knowledge resulting from NASA, Army, and industry research programs over the last 5 to 10 years. Topics addressed in this volume include: materials and structures; propulsion and drive systems; flight dynamics and control; and acoustics.

  1. 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…

  2. 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

  3. 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

  4. Population Dynamics and Flight Phenology Model of Codling Moth Differ between Commercial and Abandoned Apple Orchard Ecosystems

    Science.gov (United States)

    Joshi, Neelendra K.; Rajotte, Edwin G.; Naithani, Kusum J.; Krawczyk, Greg; Hull, Larry A.

    2016-01-01

    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., PETE 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. PMID:27713702

  5. 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

  6. Dynamics of a variable mass system applied to spacecraft rocket attitude theory

    Science.gov (United States)

    Mudge, Jason Dominic

    This research project is a study of the dynamics of a variable mass system. The scope of this research project is to gain understanding as to how a variable mass system will behave. The intent is to bring the level of understanding of variable mass dynamics higher and closer to the level of constant mass dynamics in the area of spacecrafts in particular. A main contribution is the finding of a set of criteria to minimize or eliminate the deviation of the nutation angle (or cone angle or angle of attack) of spacecraft rockets passively, i.e. without active control. The motivation for this research project is the Star 48 anomaly. The Star 48 is a solid rocket motor which has propelled (boosted) communication satellites from lower earth orbit to a higher one during the 1980's. The anomaly is that when the spacecraft rocket is being propelled, the nutation angle may deviate excessively which is considered undesirable. In the first part of this research project, a variable mass system is described and defined and the governing equations are derived. The type of governing equations derived are those that are most useful for analyzing the motion of a spacecraft rocket. The method of derivation makes use of Leibnitz Theorem, Divergence Theorem and Newton's Second Law of Motion. Next, the governing equations are specialized with several assumptions which are generally accepted assumptions applied in the analysis of spacecraft rockets. With these assumptions, the form governing equations is discussed and then the equations are solved analytically for the system's angular velocity. Having solved for the angular velocity of the system, the attitude of the system is obtained using a unique method which circumvents the nonlinearities that exist using Euler Angles and their kinematical equations. The attitude is approximately found analytically and a set of criteria is discussed which will minimize or eliminate the deviation of the nutation angle of a spacecraft rocket. Finally

  7. A system dynamics approach for modeling construction workers' safety attitudes and behaviors.

    Science.gov (United States)

    Shin, Mingyu; Lee, Hyun-Soo; Park, Moonseo; Moon, Myunggi; Han, Sangwon

    2014-07-01

    Construction accidents are caused by an unsafe act (i.e., a person's behavior or activity that deviates from normal accepted safe procedure) and/or an unsafe condition (i.e., a hazard or an unsafe mechanical or physical environment). While there has been dramatic improvement in creating safer construction environments, relatively little is known regarding the elimination of construction workers' unsafe acts. To address this deficiency, this paper aims to develop a system dynamics (SD)-based model of construction workers' mental processes that can help analyze the feedback mechanisms and the resultant dynamics regarding the workers' safety attitudes and safe behaviors. The developed model is applied to examine the effectiveness of three safety improvement policies: incentives for safe behaviors, and increased levels of communication and immersion in accidents. Application of the model verifies the strong potential of the developed model to provide a better understanding of how to eliminate unsafe acts, and to function as a robust test-bed to assess the effectiveness of safety programs or training sessions before their implementation.

  8. 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.

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

    Science.gov (United States)

    Wölfer, Ralf; Schmid, Katharina; Hewstone, Miles; van Zalk, Maarten

    2016-09-01

    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 approach to investigate intergroup contact (N = 6,457; Mage  = 14.91 years). Study 2 explored the developmental trajectories of intergroup contact by applying this validated network approach in a cross-sequential design (four-cohort-four-wave; N = 3,815; 13-26 years). Accelerated growth curve models showed that contact predicts the development of attitudes in adolescence, whereas acquired attitudes buffer against decreasing contact in adulthood. Findings highlight the potential of social network analysis and the developmental importance of early intergroup contact experiences. PMID:27684399

  10. Rosetta lander Philae: Flight Dynamics analyses for landing site selection and post-landing operations

    Science.gov (United States)

    Jurado, Eric; Martin, Thierry; Canalias, Elisabet; Blazquez, Alejandro; Garmier, Romain; Ceolin, Thierry; Gaudon, Philippe; Delmas, Cedric; Biele, Jens; Ulamec, Stephan; Remetean, Emile; Torres, Alex; Laurent-Varin, Julien; Dolives, Benoit; Herique, Alain; Rogez, Yves; Kofman, Wlodek; Jorda, Laurent; Zakharov, Vladimir; Crifo, Jean-François; Rodionov, Alexander; Heinish, P.; Vincent, Jean-Baptiste

    2016-08-01

    On the 12th of November 2014, The Rosetta Lander Philae became the first spacecraft to softly land on a comet nucleus. Due to the double failure of the cold gas hold-down thruster and the anchoring harpoons that should have fixed Philae to the surface, it spent approximately two hours bouncing over the comet surface to finally come at rest one km away from its target site. Nevertheless it was operated during the 57 h of its First Science Sequence. The FSS, performed with the two batteries, should have been followed by the Long Term Science Sequence but Philae was in a place not well illuminated and fell into hibernation. Yet, thanks to reducing distance to the Sun and to seasonal effect, it woke up at end of April and on 13th of June it contacted Rosetta again. To achieve this successful landing, an intense preparation work had been carried out mainly between August and November 2014 to select the targeted landing site and define the final landing trajectory. After the landing, the data collected during on-comet operations have been used to assess the final position and orientation of Philae, and to prepare the wake-up. This paper addresses the Flight Dynamics studies done in the scope of this landing preparation from Lander side, in close cooperation with the team at ESA, responsible for Rosetta, as well as for the reconstruction of the bouncing trajectory and orientation of the Lander after touchdown.

  11. The Impact of Ada and Object-Oriented Design in NASA Goddard's Flight Dynamics Division

    Science.gov (United States)

    Waligora, Sharon; Bailey, John; Stark, Mike

    1996-01-01

    This paper presents the highlights and key findings of 10 years of use and study of Ada and object-oriented design in NASA Goddard's Flight Dynamics Division (FDD). In 1985, the Software Engineering Laboratory (SEL) began investigating how the Ada language might apply to FDD software development projects. Although they began cautiously using Ada on only a few pilot projects, they expected that, if the Ada pilots showed promising results, the FDD would fully transition its entire development organization from FORTRAN to Ada within 10 years. However, 10 years later, the FDD still produced 80 percent of its software in FORTRAN and had begun using C and C++, despite positive results on Ada projects. This paper presents the final results of a SEL study to quantify the impact of Ada in the FDD, to determine why Ada has not flourished, and to recommend future directions regarding Ada. Project trends in both languages are examined as are external factors and cultural issues that affected the infusion of this technology. The detailed results of this study were published in a formal study report in March of 1995. This paper supersedes the preliminary results of this study that were presented at the Eighteenth Annual Software Engineering Workshop in 1993.

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

    Science.gov (United States)

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

    2014-06-01

    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. PMID:24855029

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

    International Nuclear Information System (INIS)

    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)

  14. 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

  15. Exploring flight crew behaviour

    Science.gov (United States)

    Helmreich, R. L.

    1987-01-01

    A programme of research into the determinants of flight crew performance in commercial and military aviation is described, along with limitations and advantages associated with the conduct of research in such settings. Preliminary results indicate significant relationships among personality factors, attitudes regarding flight operations, and crew performance. The potential theoretical and applied utility of the research and directions for further research are discussed.

  16. 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...

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

    OpenAIRE

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

    2010-01-01

    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 pe...

  18. 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.

  19. Satellite Attitude Control System Design Taking into Account the Fuel Slosh and Flexible Dynamics

    Directory of Open Access Journals (Sweden)

    Alain G. de Souza

    2014-01-01

    Full Text Available The design of the spacecraft Attitude Control System (ACS becomes more complex when the spacecraft has different type of components like, flexible solar panels, antennas, mechanical manipulators and tanks with fuel. The interaction between the fuel slosh motion, the panel’s flexible motion and the satellite rigid motion during translational and/or rotational manoeuvre can change the spacecraft center of mass position damaging the ACS pointing accuracy. This type of problem can be considered as a Fluid-Structure Interaction (FSI where some movable or deformable structure interacts with an internal fluid. This paper develops a mathematical model for a rigid-flexible satellite with tank with fuel. The slosh dynamics is modelled using a common pendulum model and it is considered to be unactuated. The control inputs are defined by a transverse body fixed force and a moment about the centre of mass. A comparative investigation designing the satellite ACS by the Linear Quadratic Regulator (LQR and Linear Quadratic Gaussian (LQG methods is done. One has obtained a significant improvement in the satellite ACS performance and robustness of what has been done previously, since it controls the rigid-flexible satellite and the fuel slosh motion, simultaneously.

  20. 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.

  1. 旋翼结冰对直升机飞行动力学特性的影响%Effect of Rotor Icing on Helicopter Flight Dynamic Characteristics

    Institute of Scientific and Technical Information of China (English)

    李国知; 曹义华

    2011-01-01

    基于旋翼冰风洞试验数据,考虑桨叶表面附着冰脱落及桨叶表面局部温度对结冰的影响,提出了旋翼结冰的工程模型,建立了直升机旋翼结冰后的飞行动力学模型,以UH-60A为样机,研究了直升机旋翼结冰后的平衡特性,分析了结冰对直升机稳定性的影响.根据有人驾驶垂直/短距起落飞机军用品质规范(MIL-F-83300)与军用旋翼飞行器驾驶品质要求(ADS-33E-PRF),分析了结冰时间、环境温度、液态水含量以及平均水滴直径对旋翼结冰后的直升机开环状态下的操纵特性、姿态敏捷性、轴间耦合特性以及垂直轴操纵功效的影响.计算结果的对比分析显示,旋翼结冰模型合理,直升机飞行动力学模型计算精度高,能够用来研究直升机旋翼结冰后的飞行动力学问题.%Based on the rotor icing tunnel data, and considering the effect of rotor blade ice shedding and local temperature variation on the rotor blade icing, an engineering rotor icing model is advanced. Then a flight dynamics modal is built of a single rotor helicopter due to icing. The trim characteristics and stability of a UH-60A helicopter in icing conditions at the hover and in the forward flight are studied in detail. Using the military specification flying qualities of piloted V/STOL aircraft (MIL-F-83300) and the handling qualities requirements for military helicopters (ADS-33E-PRF), the effect of icing on the controllability, attitude quickness, interaxis coupling, and vertical axis control power of the helicopter open-loop system are analyzed in terms of icing time, atmospheric temperature, liquid water content, and median volumetric diameter. Calculation results indicate that the rotor icing model and the iced helicopter dynamics model are feasible and effective, and that they can be used to investigate issues in helicopter dynamics in rotor icing conditions.

  2. Dynamically Scaled Modular Aircraft for Flight-Based Aviation Safety Research Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Area-I, Incorporated personnel have led the design, fabrication, and flight testing of twelve unmanned aircraft and one manned aircraft. Partnered with NASA and...

  3. Bifurcation Tools for Flight Dynamics Analysis and Control System Design Project

    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. Evolution of the 'Trick' Dynamic Software Executive and Model Libraries for Reusable Flight Software Project

    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...

  5. Coupled rotor/fuselage dynamic analysis of the AH-1G helicopter and correlation with flight vibrations data

    Science.gov (United States)

    Corrigan, J. C.; Cronkhite, J. D.; Dompka, R. V.; Perry, K. S.; Rogers, J. P.; Sadler, S. G.

    1989-01-01

    Under a research program designated Design Analysis Methods for VIBrationS (DAMVIBS), existing analytical methods are used for calculating coupled rotor-fuselage vibrations of the AH-1G helicopter for correlation with flight test data from an AH-1G Operational Load Survey (OLS) test program. The analytical representation of the fuselage structure is based on a NASTRAN finite element model (FEM), which has been developed, extensively documented, and correlated with ground vibration test. One procedure that was used for predicting coupled rotor-fuselage vibrations using the advanced Rotorcraft Flight Simulation Program C81 and NASTRAN is summarized. Detailed descriptions of the analytical formulation of rotor dynamics equations, fuselage dynamic equations, coupling between the rotor and fuselage, and solutions to the total system of equations in C81 are included. Analytical predictions of hub shears for main rotor harmonics 2p, 4p, and 6p generated by C81 are used in conjunction with 2p OLS measured control loads and a 2p lateral tail rotor gearbox force, representing downwash impingement on the vertical fin, to excite the NASTRAN model. NASTRAN is then used to correlate with measured OLS flight test vibrations. Blade load comparisons predicted by C81 showed good agreement. In general, the fuselage vibration correlations show good agreement between anslysis and test in vibration response through 15 to 20 Hz.

  6. Attitude Dynamics of a Liquid—filled Spacecraft with a manipulator

    Institute of Scientific and Technical Information of China (English)

    JunfengLI; ZhaolinWANG

    1997-01-01

    This paper studies the influence of manipulators motion on spacecraft's attitutde,discusses how to regulate liquid-filled spacecraft's attitutde using manipulators and how to coordinate relations between the operation of manipulators and attitude stbility of spacecraft.The results show that the factors offecting the attitude of liquid-filled spacecraft are not only path of manipulator's motion,but also time and law of manipulator's motion,and viscosity,mass,inertial tensor of liquied in the spacecraft.Among these factors,influence of time of manipulator's motion is remarkable.The slower the movement of manipulators the stronger its influence on the attitude of spacecraft.Selecting law of joint angles and operation time of manipulators may perform the coordinate manipulators operation and attitude stability of spacecraft.

  7. Associations between Psycho-Educational Determinants and Dynamic Career Attitudes among undergradutes students

    OpenAIRE

    Karavdic, Senad; Karathanasi, Chrysoula; Le Bihan, Etienne; Baumann, Michèle

    2014-01-01

    Monitoring and assessment of career attitudes are critical for the student’s preparation for an adapted university-to-work transition. This problem remains partially addressed though optimal services proposed by universities which may enhance students’ generic career capabilities. Our study explored the relationships between the psycho-educational and socio-demographic factors, and the perception of their career attitudes. Bachelor students in social sciences, engineering, applied management ...

  8. 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.

  9. Software Design on Dynamic Simulation of Flight for a Certain UAV%某型无人机飞行动力学仿真软件设计

    Institute of Scientific and Technical Information of China (English)

    路引; 璟陈睿; 王道波

    2015-01-01

    无人机飞行动力学仿真是无人机飞行控制系统半实物仿真系统的重要组成部分。为了开发一种实用型的无人机飞行动力学仿真软件,考虑无人机飞行动力学仿真的实时性和精度问题,基于四阶龙格-库塔算法,对无人机飞行动力学非线性模型的实时仿真进行研究,设计和开发了无人机飞行动力学实时仿真软件,并成功应用于某型无人机飞行控制系统的半物理仿真试验。试验和测试结果表明:该动力学仿真软件设计合理并满足飞行仿真要求,具有一定的工程应用价值。%Software design on dynamic simulation of flight is an important part of hardware-in-loop simulation of flight control system for UAV. In order to develop a practical flight dynamic simulation software for UAV, considering the real-time and precision of flight dynamic simulation for UAV, real-time simulation of flight dynamic nonlinear model for UAV is studied based on four order Runge-Kutta algorithm. A kind of practical flight dynamic simulation software for UAV is designed and developed and applied to hardware-in-loop simulation experiment of flight control system for UAV successfully. The testing results show that the software design on dynamic simulation is reasonable and satisfied with the requirements of flight simulation quality, with further engineering applications.

  10. Attitude Control Enhancement Using Distributed Wing Load Sensing for Dynamic Servoelastic Control Project

    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...

  11. A Light Weight, Mini Inertial Measurement System for Position and Attitude Estimation on Dynamic Platforms Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Impact Technologies, LLC in collaboration with the Rochester Institute of Technology, proposes to develop and demonstrate a flight-worthy hardware prototype of a...

  12. Procedural guide for modeling and analyzing the flight dynamics of the SH-60B helicopter using Flightlab

    OpenAIRE

    Wagner, Roy C.

    1995-01-01

    This thesis uses Flightlab to model and analyze the flight dynamics of the SH-6OB Seahawk helicopter. Flightlab runs on computers utilizing the UNIX operating system and is used for design, analysis and testing of an aircraft using non-linear modeling techniques. It is capable of modeling conventional main rotor-tail rotor and tandem rotor helicopters and tilt rotor aircraft. A procedural guide for modeling and analyzing a single main rotor helicopter is presented using the SH-60B. The non-li...

  13. Precision Integrated Power and Attitude Control System (IPACS) in the Presence of Dynamic Uncertainty

    Science.gov (United States)

    Kim, D.; MacKunis, W.; Fitz-Coy, N.; Dixon, W. E.

    2011-01-01

    An adaptive robust integrated power and attitude control system (IPACS) is presented for a variable speed control moment gyroscope (VSCMG)-actuated satellite. The developed IPACS method is capable of achieving precision attitude control while simultaneously achieving asymptotic power tracking for a rigid-body satellite in the presence of uncertain friction in the VSCMG gimbals and wheels. In addition, the developed controller compensates for the effects of uncertain, time-varying satellite inertia properties. Some challenges encountered in the control design are that the control input is premultiplied by a nonsquare, time-varying, nonlinear, uncertain matrix and is embedded in a discontinuous nonlinear. Globally uniformly ultimately bounded attitude tracking and asymptotic power tracking results are proven via Lyapunov stability analyses, and simulation results are provided to demonstrate the performance of the controller.

  14. 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.

  15. Coupled Orbit-Attitude Dynamics of High Area-to-Mass Ratio (HAMR) Objects: Influence of Solar Radiation Pressure, Earth's Shadow and the Visibility in Light Curves

    CERN Document Server

    Frueh, Carolin; Kelecy, Thomas

    2013-01-01

    The orbital and attitude dynamics of uncontrolled Earth orbiting objects are perturbed by a variety of sources. In research, emphasis has been put on operational space vehicles. Operational satellites typically have a relatively compact shape, and hence, a low area-to-mass ratio (AMR), and are in most cases actively or passively attitude stabilized. This enables one to treat the orbit and attitude propagation as decoupled problems, and in many cases the attitude dynamics can be neglected completely. The situation is different for space debris objects, which are in an uncontrolled attitude state. Furthermore, the assumption that a steady-state attitude motion can be averaged over data reduction intervals may no longer be valid. Additionally, a subset of the debris objects have significantly high area-to-mass ratio values, resulting in highly perturbed orbits, e.g. by solar radiation pressure, even if a stable AMR value is assumed. This assumption implies a steady-state attitude such that the average cross-sect...

  16. Microscopic observation of carrier-transport dynamics in quantum-structure solar cells using a time-of-flight technique

    Energy Technology Data Exchange (ETDEWEB)

    Toprasertpong, Kasidit; Fujii, Hiromasa; Sugiyama, Masakazu; Nakano, Yoshiaki [School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032 (Japan); Kasamatsu, Naofumi; Kada, Tomoyuki; Asahi, Shigeo; Kita, Takashi [Graduate School of Engineering, Kobe University, Nada-ku, Kobe 657-8501 (Japan); Wang, Yunpeng; Watanabe, Kentaroh [Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo 153-8904 (Japan)

    2015-07-27

    In this study, we propose a carrier time-of-flight technique to evaluate the carrier transport time across a quantum structure in an active region of solar cells. By observing the time-resolved photoluminescence signal with a quantum-well probe inserted under the quantum structure at forward bias, the carrier transport time can be efficiently determined at room temperature. The averaged drift velocity shows linear dependence on the internal field, allowing us to estimate the quantum structure as a quasi-bulk material with low effective mobility containing the information of carrier dynamics. We show that this direct and real-time observation is more sensitive to carrier transport than other conventional techniques, providing better insights into microscopic carrier transport dynamics to overcome a device design difficulty.

  17. 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.

  18. 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.

  19. 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

  20. Method and system for detecting a failure or performance degradation in a dynamic system such as a flight vehicle

    Science.gov (United States)

    Miller, Robert H. (Inventor); Ribbens, William B. (Inventor)

    2003-01-01

    A method and system for detecting a failure or performance degradation in a dynamic system having sensors for measuring state variables and providing corresponding output signals in response to one or more system input signals are provided. The method includes calculating estimated gains of a filter and selecting an appropriate linear model for processing the output signals based on the input signals. The step of calculating utilizes one or more models of the dynamic system to obtain estimated signals. The method further includes calculating output error residuals based on the output signals and the estimated signals. The method also includes detecting one or more hypothesized failures or performance degradations of a component or subsystem of the dynamic system based on the error residuals. The step of calculating the estimated values is performed optimally with respect to one or more of: noise, uncertainty of parameters of the models and un-modeled dynamics of the dynamic system which may be a flight vehicle or financial market or modeled financial system.

  1. Flight selection at United Airlines

    Science.gov (United States)

    Traub, W.

    1980-01-01

    Airline pilot selection proceedures are discussed including psychogical and personality tests, psychomotor performance requirements, and flight skills evaluation. Necessary attitude and personality traits are described and an outline of computer selection, testing, and training techniques is given.

  2. Discrete Neural Altitude Control for Hypersonic Vehicle Via Flight Path Angle Tracking

    Directory of Open Access Journals (Sweden)

    Shixing Wang

    2012-09-01

    Full Text Available In this study, the altitude control is analyzed for the longitudinal dynamics of a generic Hypersonic Flight Vehicle (HFV. By transforming altitude command into the tracking of flight path angle with fast dynamics, the system design is focusing on the control of the attitude subsystem. The virtual control is designed with nominal feedback and Neural Network (NN approximation via back-stepping. Under the proposed controller, the Semiglobal Uniform Ultimate Boundedness (SGUUB stability is guaranteed. The slow dynamics are transformed into the parameter estimation problem and the update law is designed. The simulation is presented to show the effectiveness of the proposed control approach.

  3. 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.

  4. Continuation Methods and Non-Linear/Non-Gaussian Estimation for Flight Dynamics Project

    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...

  5. 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. PMID:22378023

  6. Analysis of ion dynamics and peak shapes for delayed extraction time-of-flight mass spectrometers

    Science.gov (United States)

    Collado, V. M.; Ponciano, C. R.; Fernandez-Lima, F. A.; da Silveira, E. F.

    2004-06-01

    The dependence of time-of-flight (TOF) peak shapes on time-dependent extraction electric fields is studied theoretically. Conditions for time focusing are analyzed both analytically and numerically for double-acceleration-region TOF spectrometers. Expressions for the spectrometer mass resolution and for the critical delay time are deduced. Effects due to a leakage field in the first acceleration region are shown to be relevant under certain conditions. TOF peak shape simulations for the delayed extraction method are performed for emitted ions presenting a Maxwellian initial energy distribution. Calculations are compared to experimental results of Cs+ emission due to CsI laser ablation.

  7. Computational Model of Human and System Dynamics in Free Flight: Studies in Distributed Control Technologies

    Science.gov (United States)

    Corker, Kevin M.; Pisanich, Gregory; Lebacqz, J. Victor (Technical Monitor)

    1998-01-01

    This paper presents a set of studies in full mission simulation and the development of a predictive computational model of human performance in control of complex airspace operations. NASA and the FAA have initiated programs of research and development to provide flight crew, airline operations and air traffic managers with automation aids to increase capacity in en route and terminal area to support the goals of safe, flexible, predictable and efficient operations. In support of these developments, we present a computational model to aid design that includes representation of multiple cognitive agents (both human operators and intelligent aiding systems). The demands of air traffic management require representation of many intelligent agents sharing world-models, coordinating action/intention, and scheduling goals and actions in a potentially unpredictable world of operations. The operator-model structure includes attention functions, action priority, and situation assessment. The cognitive model has been expanded to include working memory operations including retrieval from long-term store, and interference. The operator's activity structures have been developed to provide for anticipation (knowledge of the intention and action of remote operators), and to respond to failures of the system and other operators in the system in situation-specific paradigms. System stability and operator actions can be predicted by using the model. The model's predictive accuracy was verified using the full-mission simulation data of commercial flight deck operations with advanced air traffic management techniques.

  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. Continuation Methods and Non-Linear/Non-Gaussian Estimation for Flight Dynamics Project

    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...

  10. Cooperative quantum-behaved particle swarm optimization with dynamic varying search areas and Lévy flight disturbance.

    Science.gov (United States)

    Li, Desheng

    2014-01-01

    This paper proposes a novel variant of cooperative quantum-behaved particle swarm optimization (CQPSO) algorithm with two mechanisms to reduce the search space and avoid the stagnation, called CQPSO-DVSA-LFD. One mechanism is called Dynamic Varying Search Area (DVSA), which takes charge of limiting the ranges of particles' activity into a reduced area. On the other hand, in order to escape the local optima, Lévy flights are used to generate the stochastic disturbance in the movement of particles. To test the performance of CQPSO-DVSA-LFD, numerical experiments are conducted to compare the proposed algorithm with different variants of PSO. According to the experimental results, the proposed method performs better than other variants of PSO on both benchmark test functions and the combinatorial optimization issue, that is, the job-shop scheduling problem. PMID:24851085

  11. Cooperative Quantum-Behaved Particle Swarm Optimization with Dynamic Varying Search Areas and Lévy Flight Disturbance

    Directory of Open Access Journals (Sweden)

    Desheng Li

    2014-01-01

    Full Text Available This paper proposes a novel variant of cooperative quantum-behaved particle swarm optimization (CQPSO algorithm with two mechanisms to reduce the search space and avoid the stagnation, called CQPSO-DVSA-LFD. One mechanism is called Dynamic Varying Search Area (DVSA, which takes charge of limiting the ranges of particles’ activity into a reduced area. On the other hand, in order to escape the local optima, Lévy flights are used to generate the stochastic disturbance in the movement of particles. To test the performance of CQPSO-DVSA-LFD, numerical experiments are conducted to compare the proposed algorithm with different variants of PSO. According to the experimental results, the proposed method performs better than other variants of PSO on both benchmark test functions and the combinatorial optimization issue, that is, the job-shop scheduling problem.

  12. 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

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

    Science.gov (United States)

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

    2015-01-01

    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. PMID:25445261

  14. Structural dynamics and attitude control study of early manned capability space station configurations

    Science.gov (United States)

    Ayers, J. Kirk; Cirillo, William M.; Giesy, Daniel P.; Hitchcock, Jay C.; Kaszubowski, Martin J.; Raney, J. Philip

    1987-01-01

    A study was performed to determine the vibration and attitude control characteristics of critical space station configurations featuring early manned capability during buildup from initial user support through the operations capability reference station. Five configurations were selected and were examined thus determining the changes that are likely to occur in the characteristics of the system as the station progresses from a single boom structure to a mature, dual keel, operations capability reference station. Both 9 foot and 5 meter truss bay sizes were investigated. All configurations analyzed were stable; however, the 5 meter truss bay size structure exhibited superior stability characteristics.

  15. The Direction of Fluid Dynamics for Liquid Propulsion at NASA Marshall Space Flight Center

    Science.gov (United States)

    Griffin, Lisa W.

    2012-01-01

    The Fluid Dynamics Branch's (ER42) at MSFC mission is to support NASA and other customers with discipline expertise to enable successful accomplishment of program/project goals. The branch is responsible for all aspects of the discipline of fluid dynamics, analysis and testing, applied to propulsion or propulsion-induced loads and environments, which includes the propellant delivery system, combustion devices, coupled systems, and launch and separation events. ER42 supports projects from design through development, and into anomaly and failure investigations. ER42 is committed to continually improving the state-of-its-practice to provide accurate, effective, and timely fluid dynamics assessments and in extending the state-of-the-art of the discipline.

  16. Dynamics of hypersonic flight vehicles exhibiting significant aeroelastic and aeropropulsive interactions

    Science.gov (United States)

    Chavez, Frank R.; Schmidt, David K.

    1993-01-01

    With analytic expressions previously developed for the forces and moments acting on a generic hypersonic vehicle, it is of interest to investigate the relative importance of the aerodynamic and propulsive effects on the vehicle dynamics. It is shown that the vehicle's aerodynamics and propulsive forces are both very significant in the evaluation of key stability derivatives which dictate the vehicle's dynamic characteristics. It is also shown that the vehicle model selected is unstable in pitch and exhibits strong airframe/engine/elastic coupling. With the use of literal expressions for both the systems poles and zeros, as well as the stability derivatives, key vehicle dynamic characteristics are investigated. For small errors, or uncertainties, in either the aerodynamic or propulsive forces, significant errors in the frequency and damping of the dominant modes and zero locations will arise.

  17. 基于多源信息的飞行姿态估计方法%Flight attitude determination base on multiple measurements

    Institute of Scientific and Technical Information of China (English)

    辛琪; 史忠科

    2012-01-01

    High-dimension Matrix inversion is essential to estimate accuracy attitude by the hybrid Extended Kalman Filter from multiple attitude aiding measurements. According to the difficulty of the high-dimension Matrix inversion, a low-order attitude determination approach based on multiple measurements is proposed. Four maneuvering attitude observation models were established firstly. And then four hybrid Extended Kalman Filters for attitude determination were employed to estimate state. Finally, the estimated states were fused by Markov Estimation. Simulation status shows that the proposed method is not only able to estimate the angular drift to guarantee the convergence , but also superior to the multiple measurements based high-dimension hybrid Extended Kalman Filter in estimation accuracy.%采用高维扩展卡尔曼滤波对多个姿态测量信息进行融合存在求解高维矩阵逆的问题,针对该问题提出了一种基于多源观测信息的低维姿态估计方法.该方法建立了四路适合机动飞行的姿态观测模型,对每路观测信息采用低维混合扩展卡尔曼滤波进行状态估计,并对每路状态估计结果采用马尔柯夫估计进行综合.试验结果表明,该方法可准确估计出角速度常值偏差以保证滤波收敛性,与基于多个测量的高维扩展卡尔曼滤波相比,具有更高的精度.

  18. 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.

  19. Using Dynamic Interface Modeling and Simulation to Develop a Launch and Recovery Flight Simulation for a UH-60A Blackhawk

    Science.gov (United States)

    Sweeney, Christopher; Bunnell, John; Chung, William; Giovannetti, Dean; Mikula, Julie; Nicholson, Bob; Roscoe, Mike

    2001-01-01

    Joint Shipboard Helicopter Integration Process (JSHIP) is a Joint Test and Evaluation (JT&E) program sponsored by the Office of the Secretary of Defense (OSD). Under the JSHDP program is a simulation effort referred to as the Dynamic Interface Modeling and Simulation System (DIMSS). The purpose of DIMSS is to develop and test the processes and mechanisms that facilitate ship-helicopter interface testing via man-in-the-loop ground-based flight simulators. Specifically, the DIMSS charter is to develop an accredited process for using a flight simulator to determine the wind-over-the-deck (WOD) launch and recovery flight envelope for the UH-60A ship/helicopter combination. DIMSS is a collaborative effort between the NASA Ames Research Center and OSD. OSD determines the T&E and warfighter training requirements, provides the programmatics and dynamic interface T&E experience, and conducts ship/aircraft interface tests for validating the simulation. NASA provides the research and development element, simulation facility, and simulation technical experience. This paper will highlight the benefits of the NASA/JSHIP collaboration and detail achievements of the project in terms of modeling and simulation. The Vertical Motion Simulator (VMS) at NASA Ames Research Center offers the capability to simulate a wide range of simulation cueing configurations, which include visual, aural, and body-force cueing devices. The system flexibility enables switching configurations io allow back-to-back evaluation and comparison of different levels of cueing fidelity in determining minimum training requirements. The investigation required development and integration of several major simulation system at the VMS. A new UH-60A BlackHawk interchangeable cab that provides an out-the-window (OTW) field-of-view (FOV) of 220 degrees in azimuth and 70 degrees in elevation was built. Modeling efforts involved integrating Computational Fluid Dynamics (CFD) generated data of an LHA ship airwake and

  20. Sallimus and the dynamics of sarcomere assembly in Drosophila flight muscles.

    Science.gov (United States)

    Orfanos, Zacharias; Leonard, Kevin; Elliott, Chris; Katzemich, Anja; Bullard, Belinda; Sparrow, John

    2015-06-19

    The Drosophila indirect flight muscles (IFM) can be used as a model for the study of sarcomere assembly. Here we use a transgenic line with a green fluorescent protein (GFP) exon inserted into the Z-disc-proximal portion of sallimus (Sls), also known as Drosophila titin, to observe sarcomere assembly during IFM development. Firstly, we confirm that Sls-GFP can be used in the heterozygote state without an obvious phenotype in IFM and other muscles. We then use Sls-GFP in the IFM to show that sarcomeres grow individually and uniformly throughout the fibre, growing linearly in length and in diameter. Finally, we show that limiting the amounts of Sls in the IFM using RNAi leads to sarcomeres with smaller Z-discs in their core, whilst the thick/thin filament lattice can form peripherally without a Z-disc. Thick filament preparations from those muscles show that although the Z-disc-containing core has thick filaments of a regular length, filaments from the peripheral lattice are longer and asymmetrical around the bare zone. Therefore, the Z-disc and Sls are required for thick filament length specification but not for the assembly of the thin/thick filament lattice.

  1. 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.

  2. Two-Aircraft Dynamic System on Approach. Flight Path and noise Optimization

    OpenAIRE

    Nahayo, F.; Khardi, S.; Haddou, M.

    2012-01-01

    The aim of this paper is to present and to solve a mathematical model of two-aircraft optimal control problem reducing noise during the approach. This is a non-convex optimal control problem governed by ordinary non-linear differential equations. A Symplectic Partitioned Runge-Kutta discretization and the Pontryaguin maximum principle are used. Discretization scheme provides a sufficiently high order requiring a computation of the partial derivatives of the aircraft dynamic parameters. The no...

  3. Research on flight dynamics model of ducted fan MAV%微型涵道飞行器飞行力学模型研究

    Institute of Scientific and Technical Information of China (English)

    蔡红明; 昂海松; 邓双厚; 张华靓

    2012-01-01

    Research on nonlinear flight dynamic mathematical model of micro air vehicles (MAV) plays an important role in MAV design. The flight dynamics of ducted fan MAV is remarkably nonlinear due to its big flight envelope, small size, low speed and special aerodynamic configuration. The aerodynamic characteristics of MAV was studied based on low Reynolds numbers wind tunnel testing, furthermore, the dynamic derivatives of the ducted fan MAV were calculated using computational fluid dynamics (CFD) method. The flight dynamic mathematical model of MAV was established based on aerodynamic characteristics, and its basic flight performance and trim results were calculated. The results indicate that the ducted fan MAV is different from conventional aircraft, it can hover, take off and landing vertically and fly forward.%微型飞行器(MAV)非线性飞行力学模型研究是MAV设计中的一个重要环节.微型涵道飞行器由于大包线、尺寸小、速度低、气动布局特殊,其飞行力学特性具有显著的非线性特性.以低雷诺数风洞实验为基础,研究了微型涵道飞行器的空气动力学特性,并采用CFD方法计算了微型涵道飞行器的动导数.在此基础上建立了微型涵道飞行器的飞行力学模型,并计算了基本飞行性能和配平曲线.结果表明,微型涵道飞行器与常规飞行器相比有很大差异,可以完成悬停、垂直起降和前飞的大包线飞行.

  4. Weak and Dynamic GNSS Signal Tracking Strategies for Flight Missions in the Space Service Volume.

    Science.gov (United States)

    Jing, Shuai; Zhan, Xingqun; Liu, Baoyu; Chen, Maolin

    2016-09-02

    Weak-signal and high-dynamics are of two primary concerns of space navigation using GNSS (Global Navigation Satellite System) in the space service volume (SSV). The paper firstly defines a reference assumption third-order phase-locked loop (PLL) as the baseline of an onboard GNSS receiver, and proves the incompetence of this conventional architecture. Then an adaptive four-state Kalman filter (KF)-based algorithm is introduced to realize the optimization of loop noise bandwidth, which can adaptively regulate its filter gain according to the received signal power and line-of-sight (LOS) dynamics. To overcome the matter of losing lock in weak-signal and high-dynamic environments, an open loop tracking strategy aided by an inertial navigation system (INS) is recommended, and the traditional maximum likelihood estimation (MLE) method is modified in a non-coherent way by reconstructing the likelihood cost function. Furthermore, a typical mission with combined orbital maneuvering and non-maneuvering arcs is taken as a destination object to test the two proposed strategies. Finally, the experiment based on computer simulation identifies the effectiveness of an adaptive four-state KF-based strategy under non-maneuvering conditions and the virtue of INS-assisted methods under maneuvering conditions.

  5. Weak and Dynamic GNSS Signal Tracking Strategies for Flight Missions in the Space Service Volume

    Directory of Open Access Journals (Sweden)

    Shuai Jing

    2016-09-01

    Full Text Available Weak-signal and high-dynamics are of two primary concerns of space navigation using GNSS (Global Navigation Satellite System in the space service volume (SSV. The paper firstly defines a reference assumption third-order phase-locked loop (PLL as the baseline of an onboard GNSS receiver, and proves the incompetence of this conventional architecture. Then an adaptive four-state Kalman filter (KF-based algorithm is introduced to realize the optimization of loop noise bandwidth, which can adaptively regulate its filter gain according to the received signal power and line-of-sight (LOS dynamics. To overcome the matter of losing lock in weak-signal and high-dynamic environments, an open loop tracking strategy aided by an inertial navigation system (INS is recommended, and the traditional maximum likelihood estimation (MLE method is modified in a non-coherent way by reconstructing the likelihood cost function. Furthermore, a typical mission with combined orbital maneuvering and non-maneuvering arcs is taken as a destination object to test the two proposed strategies. Finally, the experiment based on computer simulation identifies the effectiveness of an adaptive four-state KF-based strategy under non-maneuvering conditions and the virtue of INS-assisted methods under maneuvering conditions.

  6. Weak and Dynamic GNSS Signal Tracking Strategies for Flight Missions in the Space Service Volume.

    Science.gov (United States)

    Jing, Shuai; Zhan, Xingqun; Liu, Baoyu; Chen, Maolin

    2016-01-01

    Weak-signal and high-dynamics are of two primary concerns of space navigation using GNSS (Global Navigation Satellite System) in the space service volume (SSV). The paper firstly defines a reference assumption third-order phase-locked loop (PLL) as the baseline of an onboard GNSS receiver, and proves the incompetence of this conventional architecture. Then an adaptive four-state Kalman filter (KF)-based algorithm is introduced to realize the optimization of loop noise bandwidth, which can adaptively regulate its filter gain according to the received signal power and line-of-sight (LOS) dynamics. To overcome the matter of losing lock in weak-signal and high-dynamic environments, an open loop tracking strategy aided by an inertial navigation system (INS) is recommended, and the traditional maximum likelihood estimation (MLE) method is modified in a non-coherent way by reconstructing the likelihood cost function. Furthermore, a typical mission with combined orbital maneuvering and non-maneuvering arcs is taken as a destination object to test the two proposed strategies. Finally, the experiment based on computer simulation identifies the effectiveness of an adaptive four-state KF-based strategy under non-maneuvering conditions and the virtue of INS-assisted methods under maneuvering conditions. PMID:27598164

  7. Weak and Dynamic GNSS Signal Tracking Strategies for Flight Missions in the Space Service Volume

    Science.gov (United States)

    Jing, Shuai; Zhan, Xingqun; Liu, Baoyu; Chen, Maolin

    2016-01-01

    Weak-signal and high-dynamics are of two primary concerns of space navigation using GNSS (Global Navigation Satellite System) in the space service volume (SSV). The paper firstly defines a reference assumption third-order phase-locked loop (PLL) as the baseline of an onboard GNSS receiver, and proves the incompetence of this conventional architecture. Then an adaptive four-state Kalman filter (KF)-based algorithm is introduced to realize the optimization of loop noise bandwidth, which can adaptively regulate its filter gain according to the received signal power and line-of-sight (LOS) dynamics. To overcome the matter of losing lock in weak-signal and high-dynamic environments, an open loop tracking strategy aided by an inertial navigation system (INS) is recommended, and the traditional maximum likelihood estimation (MLE) method is modified in a non-coherent way by reconstructing the likelihood cost function. Furthermore, a typical mission with combined orbital maneuvering and non-maneuvering arcs is taken as a destination object to test the two proposed strategies. Finally, the experiment based on computer simulation identifies the effectiveness of an adaptive four-state KF-based strategy under non-maneuvering conditions and the virtue of INS-assisted methods under maneuvering conditions. PMID:27598164

  8. The Brain Is Faster than the Hand in Split-Second Intentions to Respond to an Impending Hazard: A Simulation of Neuroadaptive Automation to Speed Recovery to Perturbation in Flight Attitude.

    Science.gov (United States)

    Callan, Daniel E; Terzibas, Cengiz; Cassel, Daniel B; Sato, Masa-Aki; Parasuraman, Raja

    2016-01-01

    The goal of this research is to test the potential for neuroadaptive automation to improve response speed to a hazardous event by using a brain-computer interface (BCI) to decode perceptual-motor intention. Seven participants underwent four experimental sessions while measuring brain activity with magnetoencephalograpy. The first three sessions were of a simple constrained task in which the participant was to pull back on the control stick to recover from a perturbation in attitude in one condition and to passively observe the perturbation in the other condition. The fourth session consisted of having to recover from a perturbation in attitude while piloting the plane through the Grand Canyon constantly maneuvering to track over the river below. Independent component analysis was used on the first two sessions to extract artifacts and find an event related component associated with the onset of the perturbation. These two sessions were used to train a decoder to classify trials in which the participant recovered from the perturbation (motor intention) vs. just passively viewing the perturbation. The BCI-decoder was tested on the third session of the same simple task and found to be able to significantly distinguish motor intention trials from passive viewing trials (mean = 69.8%). The same BCI-decoder was then used to test the fourth session on the complex task. The BCI-decoder significantly classified perturbation from no perturbation trials (73.3%) with a significant time savings of 72.3 ms (Original response time of 425.0-352.7 ms for BCI-decoder). The BCI-decoder model of the best subject was shown to generalize for both performance and time savings to the other subjects. The results of our off-line open loop simulation demonstrate that BCI based neuroadaptive automation has the potential to decode motor intention faster than manual control in response to a hazardous perturbation in flight attitude while ignoring ongoing motor and visual induced activity

  9. Attitudes and attitude change

    DEFF Research Database (Denmark)

    Scholderer, Joachim

    2010-01-01

    attitude theory. Why is this important? Attitudinal concepts can be found in every area of marketing. Concepts like ad liking, brand attitude, quality perception, product preference, perceived benefit, perceived risk, perceived value, and customer satisfaction can all be understood as particular types...... of attitudes. This is the reason why a thorough understanding of attitudes is one of the most important skills a marketer can have. That same is true in related areas such as communications research: concepts like public opinion, corporate reputation, and corporate image are nothing more than particular types...

  10. ADAPTIVE FLIGHT CONTROL SYSTEM OF ARMED HELICOPTER USING WAVELET NEURAL NETWORK METHOD

    Institute of Scientific and Technical Information of China (English)

    ZHURong-gang; JIANGChangsheng; FENGBin

    2004-01-01

    A discussion is devoted to the design of an adaptive flight control system of the armed helicopter using wavelet neural network method. Firstly, the control loop of the attitude angle is designed with a dynamic inversion scheme in a quick loop and a slow loop. respectively. Then, in order to compensate the error caused by dynamic inversion, the adaptive flight control system of the armed helicopter using wavelet neural network method is put forward, so the BP wavelet neural network and the Lyapunov stable wavelet neural network are used to design the helicopter flight control system. Finally, the typical maneuver flight is simulated to demonstrate its validity and effectiveness. Result proves that the wavelet neural network has an engineering practical value and the effect of WNN is good.

  11. 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.

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

    International Nuclear Information System (INIS)

    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

  13. 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.

  14. A flight-dynamic helicopter mathematical model with a single flap-lag-torsion main rotor

    Science.gov (United States)

    Takahashi, Marc D.

    1990-01-01

    A mathematical model of a helicopter system with a single main rotor that includes rigid, hinge-restrained rotor blades with flap, lag, and torsion degrees of freedom is described. The model allows several hinge sequences and two offsets in the hinges. Quasi-steady Greenberg theory is used to calculate the blade-section aerodynamic forces, and inflow effects are accounted for by using three-state nonlinear dynamic inflow model. The motion of the rigid fuselage is defined by six degrees of freedom, and an optional rotor rpm degree of freedom is available. Empennage surfaces and the tail rotor are modeled, and the effect of main-rotor downwash on these elements is included. Model trim linearization, and time-integration operations are described and can be applied to a subset of the model in the rotating or nonrotating coordinate frame. A preliminary validation of the model is made by comparing its results with those of other analytical and experimental studies. This publication presents the results of research compiled in November 1989.

  15. The effect of removing the N-terminal extension of the Drosophila myosin regulatory light chain upon flight ability and the contractile dynamics of indirect flight muscle.

    OpenAIRE

    Moore, J R; Dickinson, M H; Vigoreaux, J O; Maughan, D W

    2000-01-01

    The Drosophila myosin regulatory light chain (DMLC2) is homologous to MLC2s of vertebrate organisms, except for the presence of a unique 46-amino acid N-terminal extension. To study the role of the DMLC2 N-terminal extension in Drosophila flight muscle, we constructed a truncated form of the Dmlc2 gene lacking amino acids 2-46 (Dmlc2(Delta2-46)). The mutant gene was expressed in vivo, with no wild-type Dmlc2 gene expression, via P-element-mediated germline transformation. Expression of the tr...

  16. Global Attitude Estimation using Single Direction Measurements

    OpenAIRE

    Lee, Taeyoung; Leok, Melvin; McClamroch, N. Harris; Sanyal, Amit K.

    2006-01-01

    A deterministic attitude estimator for a rigid body under an attitude dependent potential is studied. This estimator requires only a single direction measurement to a known reference point at each measurement instant. The measurement cannot completely determine the attitude, but an attitude estimation scheme based on this measurement is developed; a feasible set compatible with the measurement is described and it is combined with an attitude dynamics model to obtain an attitude estimate. The ...

  17. Design of a Parallel Robot with a Large Workspace for the Functional Evaluation of Aircraft Dynamics beyond the Nominal Flight Envelope

    Directory of Open Access Journals (Sweden)

    Umar Asif

    2012-08-01

    Full Text Available This paper summarizes the development of a robotic system for the analysis of aircraft dynamics within and beyond the nominal flight envelope. The paper proposes the development of a parallel robot and its motion cueing algorithm to attain a reasonable workspace with adequate motion capabilities to facilitate the testing of aircraft stall and fault manoeuvrability scenarios. The proposed design combines two parallel mechanisms and aims to provide six degrees of freedom motion with a much larger motion envelope than the conventional hexapods in order to realize the manoeuvrability matching of aircraft dynamics near and beyond the upset flight envelopes. Finally the paper draws a comparative evaluation of motion capabilities between the proposed motion platform and a conventional hexapod based on Stewart configuration in order to emphasize the significance of the design proposed herein.

  18. Design of a Parallel Robot with a Large Workspace for the Functional Evaluation of Aircraft Dynamics beyond the Nominal Flight Envelope

    OpenAIRE

    Umar Asif

    2012-01-01

    This paper summarizes the development of a robotic system for the analysis of aircraft dynamics within and beyond the nominal flight envelope. The paper proposes the development of a parallel robot and its motion cueing algorithm to attain a reasonable workspace with adequate motion capabilities to facilitate the testing of aircraft stall and fault manoeuvrability scenarios. The proposed design combines two parallel mechanisms and aims to provide six degrees of freedom motion with a much larg...

  19. Reconfigurable Flight Control Design for Combat Flying Wing with Multiple Control Surfaces

    Institute of Scientific and Technical Information of China (English)

    WANG Lei; WANG Lixin

    2012-01-01

    With control using redundant multiple control surface arrangement and large-deflection drag rudders,a combat flying wing has a higher probability for control surface failures.Therefore,its flight control system must be able to reconfigure after such failures.Considering three types of typical control surface failures (lock-in-place (LIP),loss-of-effectiveness (LOE) and float),flight control reconfiguration characteristic and capability of such aircraft types are analyzed.Because of the control surface redundancy,the aircraft using the dynamic inversion flight control law already has a control allocation block.In this paper,its flight control configuration during the above failures is achieved by modifying this block.It is shown that such a reconfigurable flight control design is valid,through numerical simulations of flight attitude control task.Results indicate that,in the circumstances of control surface failures with limited degree and the degradation of the flying quality level,a combat flying wing adopting this flight control reconfiguration approach based on control allocation could guarantee its flight safety and perform some flight combat missions.

  20. The Brain is Faster than the Hand in Split-Second Intentions to Respond to an Impending Hazard: A Simulation of Neuroadaptive Automation to Speed Recovery to Perturbation in Flight Attitude

    Directory of Open Access Journals (Sweden)

    Daniel E. Callan

    2016-04-01

    Full Text Available The goal of this research is to test the potential for neuroadaptive automation to improve response speed to a hazardous event by using a brain-computer interface (BCI to decode perceptual-motor intention. Seven participants underwent four experimental sessions while measuring brain activity with magnetoencephalograpy. The first three sessions were of a simple constrained task in which the participant was to pull back on the control stick to recover from a perturbation in attitude in one condition and to passively observe the perturbation in the other condition. The fourth session consisted of having to recover from a perturbation in attitude while piloting the plane through the Grand Canyon constantly maneuvering to track over the river below. Independent component analysis was used on the first two sessions to extract artifacts and find an event related component associated with the onset of the perturbation. These two sessions were used to train a decoder to classify trials in which the participant recovered from the perturbation (motor intention versus just passively viewing the perturbation. The BCI-decoder was tested on the third session of the same simple task and found to be able to significantly distinguish motor intention trials from passive viewing trials (mean = 69.8%. The same BCI-decoder was then used to test the fourth session on the complex task. The BCI-decoder significantly classified perturbation from no perturbation trials (73.3% with a significant time savings of 72.3ms (Original response time of 425.0ms to 352.7ms for BCI-decoder. The BCI-decoder model of the best subject was shown to generalize for both performance and time savings to the other subjects. The results of our off-line open loop simulation demonstrate that BCI based neuroadaptive automation has the potential to decode motor intention faster than manual control in response to a hazardous perturbation in flight attitude while ignoring ongoing motor and visual

  1. 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.

  2. 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. PMID:16318599

  3. Integrated inertial stellar attitude sensor

    Science.gov (United States)

    Brady, Tye M. (Inventor); Kourepenis, Anthony S. (Inventor); Wyman, Jr., William F. (Inventor)

    2007-01-01

    An integrated inertial stellar attitude sensor for an aerospace vehicle includes a star camera system, a gyroscope system, a controller system for synchronously integrating an output of said star camera system and an output of said gyroscope system into a stream of data, and a flight computer responsive to said stream of data for determining from the star camera system output and the gyroscope system output the attitude of the aerospace vehicle.

  4. Attitude determination for balloon-borne experiments

    CERN Document Server

    Gandilo, N N; Amiri, M; Angile, F E; Benton, S J; Bock, J J; Bond, J R; Bryan, S A; Chiang, H C; Contaldi, C R; Crill, B P; Devlin, M J; Dober, B; Dore, O P; Farhang, M; Filippini, J P; Fissel, L M; Fraisse, A A; Fukui, Y; Galitzki, N; Gambrel, A E; Golwala, S; Gudmundsson, J E; Halpern, M; Hasselfield, M; Hilton, G C; Holmes, W A; Hristov, V V; Irwin, K D; Jones, W C; Kermish, Z D; Klein, J; Korotkov, A L; Kuo, C L; MacTavish, C J; Mason, P V; Matthews, T G; Megerian, K G; Moncelsi, L; Morford, T A; Mroczkowski, T K; Nagy, J M; Netterfield, C B; Novak, G; Nutter, D; O'Brient, R; Pascale, E; Poidevin, F; Rahlin, A S; Reintsema, C D; Ruhl, J E; Runyan, M C; Savini, G; Scott, D; Shariff, J A; Soler, J D; Thomas, N E; Trangsrud, A; Truch, M D; Tucker, C E; Tucker, G S; Tucker, R S; Turner, A D; Ward-Thompson, D; Weber, A C; Wiebe, D V; Young, E Y

    2014-01-01

    An attitude determination system for balloon-borne experiments is presented. The system provides pointing information in azimuth and elevation for instruments flying on stratospheric balloons over Antarctica. In-flight attitude is given by the real-time combination of readings from star cameras, a magnetometer, sun sensors, GPS, gyroscopes, tilt sensors and an elevation encoder. Post-flight attitude reconstruction is determined from star camera solutions, interpolated by the gyroscopes using an extended Kalman Filter. The multi-sensor system was employed by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol), an experiment that measures polarized thermal emission from interstellar dust clouds. A similar system was designed for the upcoming flight of SPIDER, a Cosmic Microwave Background polarization experiment. The pointing requirements for these experiments are discussed, as well as the challenges in designing attitude reconstruction systems for high altitude balloon flights. ...

  5. Attitude Representations for Kalman Filtering

    Science.gov (United States)

    Markley, F. Landis; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    The four-component quaternion has the lowest dimensionality possible for a globally nonsingular attitude representation, it represents the attitude matrix as a homogeneous quadratic function, and its dynamic propagation equation is bilinear in the quaternion and the angular velocity. The quaternion is required to obey a unit norm constraint, though, so Kalman filters often employ a quaternion for the global attitude estimate and a three-component representation for small errors about the estimate. We consider these mixed attitude representations for both a first-order Extended Kalman filter and a second-order filter, as well for quaternion-norm-preserving attitude propagation.

  6. Consumers’ Attitude towards Advertising

    OpenAIRE

    Uchenna Cyril Eze; Chai Har Lee

    2012-01-01

    Advertising is a growing business and with advances in the Internet technology, the dynamics and landscape ofthe business has changed as well. Prior findings on consumers’ attitude towards advertising are mixed. Thispaper is an attempt to examine young adults’ attitude towards advertising. We conceptualized a framework toexamine the influence of six independent variables namely consumer manipulation, product information,hedonic/pleasure, economic condition, social integration, and materialism...

  7. Two-dimensional and three-dimensional dynamic imaging of live biofilms in a microchannel by time-of-flight secondary ion mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hua, Xin; Marshall, Matthew J.; Xiong, Yijia; Ma, Xiang; Zhou, Yufan; Tucker, Abigail E.; Zhu, Zihua; Liu, Songqin; Yu, Xiao-Ying

    2015-05-01

    A vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface) was employed for in situ chemical imaging of live biofilms using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Depth profiling by sputtering materials in sequential layers resulted in live biofilm spatial chemical mapping. 2D images were reconstructed to report the first 3D images of hydrated biofilm elucidating spatial and chemical heterogeneity. 2D image principal component analysis (PCA) was conducted among biofilms at different locations in the microchannel. Our approach directly visualized spatial and chemical heterogeneity within the living biofilm by dynamic liquid ToF-SIMS.

  8. Solid Launcher Dynamical Analysis and Autopilot Design

    Directory of Open Access Journals (Sweden)

    Ping Sun

    2011-02-01

    Full Text Available The dynamics of a small solid launch vehicle has been investigated. This launcher consists of a liquid upper stage and three fundamental solid rocket boosters aligned in series. During the ascent flight phase, lateral jets and grid fins are adopted by the flight control system to stable the attitude of the launcher. The launcher is a slender and aerodynamically unstable vehicle with sloshing tanks. A complete set of six-degrees-of-freedom dynamic models of the launcher, incorporation its rigid body, aerodynamics, gravity, sloshing, mass change, actuator, and elastic body, is developed. Dynamic analysis results of the structural modes and the bifurcation locus are calculated on the basis of the presented models. This complete set of dynamic models is used in flight control system design. A methodology for employing numerical optimization to develop the attitude filters is presented. The design objectives include attitude tracking accuracy and robust stability with respect to rigid body dynamics, propellant slosh, and flex. Later a control approach is presented for flight control system of the launcher using both State Dependent Riccati Equation (SDRE method and Fast Output Sampling (FOS technique. The dynamics and kinematics for attitude stable problem are of typical nonlinear character. SDRE technique has been well applied to this kind of highly nonlinear control problems. But in practice the system states needed in the SDRE method are sometimes difficult to obtain. FOS method, which makes use of only the output samples, is combined with SDRE to accommodate the incomplete system state information. Thus, the control approach is more practical and easy to implement. The resulting autopilot can provide stable control systems for the vehicle.

  9. Attitude control and stabilization technology discipline

    Science.gov (United States)

    Sunkel, John W.

    1990-01-01

    Viewgraphs on attitude control and stabilization technology discipline for the Space Station Freedom are presented. Topics covered include: attitude control technologies for multi-user accommodation; flexible dynamics and control; computational control techniques; and automatic proximity operations.

  10. 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.

  11. Calibration of 5-hole Probe for Flow Angles from Advanced Technologies Testing Aircraft System Flight Data

    Directory of Open Access Journals (Sweden)

    Y. Parameswaran

    2004-04-01

    Full Text Available This paper describes the investigations carried out to calibrate the 5-hole probe for flow angles from advanced technologies testing aircraft system flight data. The flight tests were carriedout with gear up and at nominal mid-centre of gravity location for two landing flap positions, Of= IN and 14°. Dynamic manoeuvres were executed to excite the short period and Dutch roll mode of the aircraft. In addition, pull up, push down and steady sideslip manoeuvres were also carried out. The data compatibility check on the recorded flight data has been carried out using maximum likelihood output error algorithm to estimate the bias, scale factor, and time delay in the pressure measurements from the 5-hole probe mounted on a noseboom in front of aircraft nose . Through a way of kinematic consistency checking, flight-validated scale factors, biases, and time delays are determined for the differential pressure measurements for both angle of attack and angle of sideslip. Also, the dynamic pressure measurement is found to have time delays. Based on the earlier investigations, it is once again confirmed that the measurements of attitude angles, obtained from the inertial platform, clearly indicate time delays referred to the other signals like linear accelerations and angular rates which are measured with the dedicated flight instrumentation package.The identified time delays in attitude angles agreed well with the inertial platform specifications. The estimates of sensitivity coefficients and scale factors from the flight data analysis correlates reasonably well with the manufacturer Rosemount calibration curves for the tested Mach range 0.23-0.53 . The flight data analysis at Mach number of about 0.59 indicateMach dependency for the angle of attack.

  12. 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…

  13. Bird Flight as a Model for a Course in Unsteady Aerodynamics

    Science.gov (United States)

    Jacob, Jamey; Mitchell, Jonathan; Puopolo, Michael

    2014-11-01

    Traditional unsteady aerodynamics courses at the graduate level focus on theoretical formulations of oscillating airfoil behavior. Aerodynamics students with a vision for understanding bird-flight and small unmanned aircraft dynamics desire to move beyond traditional flow models towards new and creative ways of appreciating the motion of agile flight systems. High-speed videos are used to record kinematics of bird flight, particularly barred owls and red-shouldered hawks during perching maneuvers, and compared with model aircraft performing similar maneuvers. Development of a perching glider and associated control laws to model the dynamics are used as a class project. Observations are used to determine what different species and sizes of birds share in their methods to approach a perch under similar conditions. Using fundamental flight dynamics, simplified models capable of predicting position, attitude, and velocity of the flier are developed and compared with the observations. By comparing the measured data from the videos and predicted and measured motions from the glider models, it is hoped that the students gain a better understanding of the complexity of unsteady aerodynamics and aeronautics and an appreciation for the beauty of avian flight.

  14. Numerical simulation of the influence of the orbiters attitude on the μg growth of InP : S crystals from an In solution during the EURECA-1 flight

    Science.gov (United States)

    Boschert, St.; Danilewsky, A. N.; Benz, K. W.

    1999-08-01

    S-doped InP crystals were grown from an In-solution in a THM arrangement during the EURECA-1 mission using the automatic mirror furnace (AMF) under microgravity conditions. The InP-crystals showed growth rate oscillations in the range of 0.8-2.0 μm/min with a period of 45 min, which is half the time of an orbit of the EURECA-1 satellite. The fluid dynamic conditions during this experiment are modelled using a 3D model with the commercial software FIDAP. The time-dependent simulation, considering thermal as well as solutal buoyancy effects, indicates a weak laminar flow in this material system. Due to the fixed attitude of the satellite with respect to the sun the residual gravity vector rotates relative to the sample axis. This rotation results in a significant change of the residual convection level. Its maximum is obtained, when the gravity is parallel to the growth interface (two times during each orbit). Due to a high Schmidt number Sc≈25 a time-dependent influence of the convection on the concentration field can also be observed.

  15. Essays on Political Actors and Attitudes: Do They Constitute Distributed Reflexivity? Part 2: A Dynamical Typology of Rationality

    OpenAIRE

    Neumann, Martin; Srbljinović, Armano

    2013-01-01

    What is the relationship between the logic that guides political attitudes of constituencies and the logic of political actors, whose legitimacy is rooted in electoral choice of the constituencies? Classical approaches, such as the median voter theorem, view political actors as passively mirroring voters’ preferences. An alternative approach, that we suggested in the first part of this series of essays, assumes that how constituencies see the competences of political actors, is crucial, in th...

  16. Attitude determination for balloon-borne experiments

    Science.gov (United States)

    Gandilo, N. N.; Ade, P. A. R.; Amiri, M.; Angilè, F. E.; Benton, S. J.; Bock, J. J.; Bond, J. R.; Bryan, S. A.; Chiang, H. C.; Contaldi, C. R.; Crill, B. P.; Devlin, M. J.; Dober, B.; Doré, O. P.; Farhang, M.; Filippini, J. P.; Fissel, L. M.; Fraisse, A. A.; Fukui, Y.; Galitzki, N.; Gambrel, A. E.; Golwala, S.; Gudmundsson, J. E.; Halpern, M.; Hasselfield, M.; Hilton, G. C.; Holmes, W. A.; Hristov, V. V.; Irwin, K. D.; Jones, W. C.; Kermish, Z. D.; Klein, J.; Korotkov, A. L.; Kuo, C. L.; MacTavish, C. J.; Mason, P. V.; Matthews, T. G.; Megerian, K. G.; Moncelsi, L.; Morford, T. A.; Mroczkowski, T. K.; Nagy, J. M.; Netterfield, C. B.; Novak, G.; Nutter, D.; O'Brient, R.; Pascale, E.; Poidevin, F.; Rahlin, A. S.; Reintsema, C. D.; Ruhl, J. E.; Runyan, M. C.; Savini, G.; Scott, D.; Shariff, J. A.; Soler, J. D.; Thomas, N. E.; Trangsrud, A.; Truch, M. D.; Tucker, C. E.; Tucker, G. S.; Tucker, R. S.; Turner, A. D.; Ward-Thompson, D.; Weber, A. C.; Wiebe, D. V.; Young, E. Y.

    2014-07-01

    An attitude determination system for balloon-borne experiments is presented. The system provides pointing information in azimuth and elevation for instruments flying on stratospheric balloons over Antarctica. In-flight attitude is given by the real-time combination of readings from star cameras, a magnetometer, sun sensors, GPS, gyroscopes, tilt sensors and an elevation encoder. Post-flight attitude reconstruction is determined from star camera solutions, interpolated by the gyroscopes using an extended Kalman Filter. The multi-sensor system was employed by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol), an experiment that measures polarized thermal emission from interstellar dust clouds. A similar system was designed for the upcoming flight of Spider, a Cosmic Microwave Background polarization experiment. The pointing requirements for these experiments are discussed, as well as the challenges in designing attitude reconstruction systems for high altitude balloon flights. In the 2010 and 2012 BLASTPol flights from McMurdo Station, Antarctica, the system demonstrated an accuracy of < 5' rms in-flight, and < 5" rms post-flight.

  17. 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…

  18. 高精度动态水平姿态传感器系统设计%The System Design for High-precision Dynamic Level Attitude Sensor

    Institute of Scientific and Technical Information of China (English)

    谈林霞; 张福学

    2011-01-01

    The level attitude detection plays an important role in the control and measurement fields.The realtime high-precision dynamic level attitude detections of the carries are the actual demands of the technical market and a challenge of the research work.Thus a high-precision level attitude dynamic detection sensor system has been designed.It is a combination of micro-machined inclinometers,micro-machined gyroscopes and the signal processing circuits.The proposed scheme uses the gyroscope to compensate the various acceleration interference brought about by the carrier in traveling,thus the high-precision dynamic level attitude detection of the traveling carrier can be realized.The overall scheme design of the system,the hardware design of its components such as the power conversion,the pre-processing of sensing signals,analog-to-digital conversion,the signal processing and the system output as well as the software design method have been presented in this paper.A sensor system was assembled and tested after the system design was carried out.The results showed that the system design was able to meet the real-time high-precision demand of the level attitude detection of the moving carriers.%水平姿态检测在控制、测量领域发挥着重要作用.实现高精度实时动态检测载体水平姿态既是科技市场的实际需求更是科研工作的挑战,因此设计了高精度动态水平姿态传感器.它主要由微机械倾角传感器、微机械陀螺及其信号处理电路组成,以陀螺来补偿载体行进中带来的各种线加速度干扰,实现移动载体的水平姿态高精度检测.以高精度与实时动态检测为核心,介绍了该系统的总体方案设计,电源转换、敏感信号预处理与模数转换、信号处理及输出的硬件设计和软件处理基本方法,并在设计完成后组装调试.系统测试表明该水平姿态检测系统设计取得预期效果,满足高精度实时动态检测载体水平姿态的设计需求.

  19. Time-of-flight study of photoinduced dynamics of copper and manganese phthalocyanine thin films on Si(111)

    Science.gov (United States)

    Ramonova, A. G.; Butkhuzi, T. G.; Abaeva, V. V.; Tvauri, I. V.; Khubezhov, S. A.; Turiev, A. M.; Tsidaeva, N. I.; Magkoev, T. T.

    2013-11-01

    Photoinduced fragmentation and desorption of species from copper phthalocyanine (CuPc) and manganese phthalocyanine 80 nm thick films deposited on Si(111) have been studied by means of atomic force microscopy and time-of-flight mass spectroscopy in an ultra-high vacuum chamber. The main fragments formed under the effect of low-fluence (1-3 mJ cm-2) nanosecond laser light with photon energies of 2.34 and 1.17 eV are the entire phthalocyanine molecule, molecular fragments, atomic Cu and Mn and a Si-substituted CuPc. The latter is presumably due to migration of the Si atom of the underlying support to the vacancy formed after photoejection of the metallic atom out of the phthalocyanine molecule. The mechanism of photofragmentation and desorption is essentially non-thermal involving the metal atom as a key factor.

  20. Attitude Of Student Teachers Towards Teaching Profession

    OpenAIRE

    BHARGAVA, Anupama; MK PATHY

    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 learning of the students. Attitude being a social construct is influenced by many factors like gender social strata ,age, stream o...

  1. Minisatellite Attitude Guidance Using Reaction Wheels

    OpenAIRE

    Ion STROE; Dan N. Dumitriu

    2015-01-01

    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 ...

  2. Understanding Flight

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, David

    2001-01-31

    Through the years the explanation of flight has become mired in misconceptions that have become dogma. Wolfgang Langewiesche, the author of 'Stick and Rudder' (1944) got it right when he wrote: 'Forget Bernoulli's Theorem'. A wing develops lift by diverting (from above) a lot of air. This is the same way that a propeller produces thrust and a helicopter produces lift. Newton's three laws and a phenomenon called the Coanda effect explain most of it. With an understanding of the real physics of flight, many things become clear. Inverted flight, symmetric wings, and the flight of insects are obvious. It is easy to understand the power curve, high-speed stalls, and the effect of load and altitude on the power requirements for lift. The contribution of wing aspect ratio on the efficiency of a wing, and the true explanation of ground effect will also be discussed.

  3. Miracle Flights

    Science.gov (United States)

    ... her future. Donate Now Make your donation today Saving Lives One Flight At A ... “To improve access to health care by providing financial assistance to low income children for commercial air ...

  4. 火箭弹大动态单轴平台惯导系统姿态算法%Attitude algorithm of high dynamic range single-axis platform INS on rocket projectile

    Institute of Scientific and Technical Information of China (English)

    王晨; 董景新; 高宗耀; 杨栓虎; 陈静

    2012-01-01

    火箭弹在飞行中常采用滚转稳定的控制方式,其滚转角速度的动态范围很大,因此实时、准确地测量滚转角速度和滚转姿态角成为制导火箭弹控制的关键问题.大动态单轴平台惯导系统将IMU安装在沿滚转方向的稳定平台上,通过伺服电机驱动单轴平台相对于弹体反旋,隔离滚转方向的大动态角速度,为IMU提供平稳的测试环境.介绍了大动态单轴平台惯导系统的组成和功能,搭建了样机,推导了惯导姿态解算的数学模型,经过120s半实物仿真试验,系统俯仰姿态角误差<4°,偏航姿态角误差<3°,滚转姿态角误差<25°,结果验证了整体方案的可行性和姿态解算模型的正确性.为进一步提高姿态解算精度,搭建单轴平台组合导航系统,实现全部导航信息的高精度测量打下了基础.%Rocket projectile often uses control mode of rolling in flight, so the dynamic range of roll rates is very high. Accurate real-time measurements of roll rates and roll angles become a key problem of rocket projectile control. High dynamic range single-axis platform INS installs IMU on the platform, drives the platform reversely spinning to the projectile body to isolate high dynamic roll rates by using servo motor, and provides stabilized environment for IMU. The composition and function of the system are introduced, the prototype is set up, and the attitude algorithm of INS is derived. The semi-physical simulation results show that the errors of pitch, heading and roll angle are less than 4 deg, 3 deg, and 25 deg respectively within 120 s. Through simulation, the feasibility of this solution and the attitude algorithm of INS are verified. It lays solid foundations for further building single-axis platform integrated navigation system and the high accurate measurements of whole navigation information.

  5. Attitude Determination for MAVs Using a Kalman Filter

    Institute of Scientific and Technical Information of China (English)

    LIU Cheng; ZHOU Zhaoying; FU Xu

    2008-01-01

    This paper presents a Kalman filter to effectively and economically determine the Euler angles for micro aerial vehicles(MAVs),whose size and payload are severely limited.The filter uses data from a series of micro-electro mechanical system sensors to determine the selected 3 vanables of the direction cosine matrix and the bias of the rata gyro sensors as state elements in a dynamic model,with the gravitational acceleration to build a measurement model.For high speed maneuvers,rigid motion equations are used to correct the measurements of the gravitational acceleration.The filter is designed to automatically tune its gain based on the dynamic system state.Simulations indicate that the Euler angles can be determined with standard deviations less than 3.The algorithm was successfully implemented in a miniature attitude measurement system suitable for MAVs.Aerobatic flights show that the attitude determination algorithm works effectively.The attitude determination algorithm is effective and economical,and can also be applied to bionic rebofishs and land vehicles,whose size and payload are also greatly limited.

  6. 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

  7. Electrochemical-acoustic time of flight: in operando correlation of physical dynamics with battery charge and health

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, AG; Bhadra, S; Hertzberg, BJ; Gjeltema, PJ; Goy, A; Fleischer, JW; Steingart, DA

    2015-01-01

    We demonstrate that a simple acoustic time-of-flight experiment can measure the state of charge and state of health of almost any closed battery. An acoustic conservation law model describing the state of charge of a standard battery is proposed, and experimental acoustic results verify the simulated trends; furthermore, a framework relating changes in sound speed, via density and modulus changes, to state of charge and state of health within a battery is discussed. Regardless of the chemistry, the distribution of density within a battery must change as a function of state of charge and, along with density, the bulk moduli of the anode and cathode changes as well. The shifts in density and modulus also change the acoustic attenuation in a battery. Experimental results indicating both state-of-charge determination and irreversible physical changes are presented for two of the most ubiquitous batteries in the world, the lithium-ion 18650 and the alkaline LR6 (AA). Overall, a one-or two-point acoustic measurement can be related to the interaction of a pressure wave at multiple discrete interfaces within a battery, which in turn provides insights into state of charge, state of health, and mechanical evolution/degradation.

  8. Dynamic subnanosecond time-of-flight detection for ultra-precise diffusion monitoring and optimization of biomarker preservation

    Science.gov (United States)

    Bauer, Daniel R.; Stevens, Benjamin; Taft, Jefferson; Chafin, David; Petre, Vinnie; Theiss, Abbey P.; Otter, Michael

    2014-03-01

    Recently, it has been demonstrated that the preservation of cancer biomarkers, such as phosphorylated protein epitopes, in formalin-fixed paraffin-embedded tissue is highly dependent on the localized concentration of the crosslinking agent. This study details a real-time diffusion monitoring system based on the acoustic time-of-flight (TOF) between pairs of 4 MHz focused transducers. Diffusion affects TOF because of the distinct acoustic velocities of formalin and interstitial fluid. Tissue is placed between the transducers and vertically translated to obtain TOF values at multiple locations with a spatial resolution of approximately 1 mm. Imaging is repeated for several hours until osmotic equilibrium is reached. A post-processing technique, analogous to digital acoustic interferometry, enables detection of subnanosecond TOF differences. Reference subtraction is used to compensate for environmental effects. Diffusion measurements with TOF monitoring ex vivo human tonsil tissue are well-correlated with a single exponential curve (R2>0.98) with a magnitude of up to 50 ns, depending on the tissue size (2-6 mm). The average exponential decay constant of 2 and 6 mm diameter samples are 20 and 315 minutes, respectively, although times varied significantly throughout the tissue (σmax=174 min). This technique can precisely monitor diffusion progression and could be used to mitigate effects from tissue heterogeneity and intersample variability, enabling improved preservation of cancer biomarkers distinctly sensitive to degradation during preanalytical tissue processing.

  9. Miracle Flights for Kids

    Science.gov (United States)

    ... today Saving Lives One Flight At A Time Miracle Flights provides free flights to distant specialized care and valuable second opinions. Miracle Flights Through June 2016 Flights Coordinated: 101,862 ...

  10. 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.

  11. Attitude tracking control for variable structure near space vehicles based on switched nonlinear systems

    Institute of Scientific and Technical Information of China (English)

    Wang Yufei; Jiang Changsheng; Wu Qingxian

    2013-01-01

    An adaptive robust attitude tracking control law based on switched nonlinear systems is presented for a variable structure near space vehicle (VSNSV) in the presence of uncertainties and disturbances.The adaptive fuzzy systems are employed for approximating unknown functions in the flight dynamic model and their parameters are updated online.To improve the flight robust performance,robust controllers with adaptive gains are designed to compensate for the approximation errors and thus they have less design conservation.Moreover,a systematic procedure is developed for the synthesis of adaptive fuzzy dynamic surface control (DSC) approach.According to the common Lyapunov function theory,it is proved that all signals of the closed-loop system are uniformly ultimately bounded by the continuous controller.The simulation results demonstrate the effectiveness and robustness of the proposed control scheme.

  12. Design of the Heat Receiver for the U.S./Russia Solar Dynamic Power Joint Flight Demonstration

    Science.gov (United States)

    Strumpf, Hal J.; Krystkowiak, Christopher; Klucher, Beth A.

    1996-01-01

    A joint U.S./Russia program is being conducted to develop, fabricate, launch, and operate a solar dynamic demonstration system on Space Station Mir. The goal of the program is to demonstrate and confirm that solar dynamic power systems are viable for future space applications such as the International Space Station Alpha The major components of the system include a heat receiver, a closed Brayton cycle power conversion unit, a power conditioning and control unit, a concentrator, a radiator, a thermal control system, and a Space Shuttle Carrier. This paper discusses the design of the heat receiver component. The receiver comprises a cylindrical cavity, the walls of which are lined with a series of tubes running the length of the cavity. The engine working fluid, a mixture of xenon and helium, is heated by the concentrated sunlight incident on these tubes. The receiver incorporates integral thermal storage, using a eutectic mixture of lithium fluoride and calcium difluoride as the thermal storage solid-to-liquid phase change materiaL This thermal storage is required to enable power production during eclipse. The phase change material is contained in a series of individual containment canisters.

  13. Summarization of Dynamic Flight Simulator and Its Development%动态飞行模拟器及其发展概述

    Institute of Scientific and Technical Information of China (English)

    宋琼; 胡荣华

    2015-01-01

    在分析载人离心机对航空生理医学研究以及飞行员高过载训练作用的基础上,详细介绍了载人离心机向动态飞行模拟器的发展历程,并对国内外发展历史、发展现状进行总结,重点介绍当代国际上主要厂家以及国内载人离心机发展历程中的代表性产品。随着我军先进战机的大量服役,国内仅有的一台引进的动态飞行模拟器已不能满足使用需求,中国工程物理研究院总体工程研究所在多年大型科学实验用离心机研制经验的基础上,开展动态飞行模拟器研制工作,目前已完成部分主要性能指标的调试工作,并根据工程研制经验对动态飞行模拟器研制过程中的关键技术以及国内未来发展趋势展开分析讨论。%ABSTRACT:Based on the analysis of human centrifuge used in aviation physiology medicine and pilot high sustained G training, the development path from human centrifuge to dynamic flight simulator (DFS) was introduced in details, the development history and current situation around the world were summarized, the representative products of major international manufacturers and domestic human centrifuge development history were introduced with emphasis. As more and more advanced fighter plane were taken into service in our army, the only one imported DFS has been unable to meet the operation demand. Based on large-scale scientific centrifuge research experience, the Institute of Structural Mechanics of Chinese Academy of Engineering Physics carried out DFS research, and the commissioning work of part key performance indicators has been finished. The related key technologies for development of dynamic flight simulator and the domestic future development trends were also analyzed and discussed.

  14. 14 CFR 125.226 - Digital flight data recorders.

    Science.gov (United States)

    2010-01-01

    ... discrete, true or magnetic); (5) Normal acceleration (Vertical); (6) Pitch attitude; (7) Roll attitude; (8...); (51) Selected vertical speed (when an information source is installed); (52) Selected heading (when an... flight data acquisition unit (FDAU), the parameters listed in paragraphs (a)(1) through (a)(18) of...

  15. A Raspberry Pi-Based Attitude Sensor

    CERN Document Server

    Sreejith, A G; Sarpotdar, Mayuresh; Mohan, Rekhesh; Nayak, Akshata; Safonova, Margarita; Murthy, Jayant

    2014-01-01

    We have developed a lightweight low-cost attitude sensor, based on a Raspberry Pi, built with readily available commercial components. It can be used in experiments where weight and power are constrained, such as in high- altitude lightweight balloon flights. This attitude sensor will be used as a major building block in a closed-loop control system with driver motors to stabilize and point cameras and telescopes for astronomical observations from a balloon-borne payload.

  16. A Raspberry Pi-Based Attitude Sensor

    Science.gov (United States)

    Sreejith, A. G.; Mathew, Joice; Sarpotdar, Mayuresh; Mohan, Rekhesh; Nayak, Akshata; Safonova, Margarita; Murthy, Jayant

    We have developed a lightweight low-cost attitude sensor, based on a Raspberry Pi, built with readily available commercial components. It can be used in experiments where weight and power are constrained, such as in high-altitude lightweight balloon flights. This attitude sensor will be used as a major building block in a closed-loop control system with driver motors to stabilize and point cameras and telescopes for astronomical observations from a balloon-borne payload.

  17. 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.

  18. Revisiting Group-Based Technology Adoption as a Dynamic Process: The Role of Changing Attitude-Rationale Configurations.

    NARCIS (Netherlands)

    Bayerl, P.S.; Lauche, K.; Axtell, C.

    2016-01-01

    In this study, we set out to better understand the dynamics behind group-based technology adoption by nvestigating the underlying mechanisms of changes in collective adoption decisions over time. Using a longitudinal multi-case study of production teams in the British oil and gas industry, we outli

  19. Classrooms as Racialized Spaces: Dynamics of Collaboration, Tension, and Student Attitudes in Urban and Suburban High Schools

    Science.gov (United States)

    Nunn, Lisa M.

    2011-01-01

    This article interrogates the construction of ethnoracial categories in everyday classroom life and how ethnoracial classroom dynamics contribute to larger patterns of inequality in achievement and unequal college futures for minorities. The study compares one urban and two suburban schools. Drawing on observation data from six classes and 57…

  20. 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.

  1. Increasing Realism and Supporting Content Planning for Dynamic Scenes in a Mixed Reality System incorporating a Time-of-Flight Camera

    Directory of Open Access Journals (Sweden)

    Reinhard Koch

    2010-09-01

    Full Text Available For broadcasting purposes mixed reality, the combination of real and virtual scene content, has become ubiquitous nowadays. Mixed Reality recording still requires expensive studio setups and is often limited to simple color keying. We present a system for Mixed Reality applications which uses depth keying and provides threedimensional mixing of real and artificial content. It features enhanced realism through automatic shadow computation which we consider a core issue to obtain realism and a convincing visual perception, besides the correct alignment of the two modalities and correct occlusion handling. Furthermore we present a possibility to support placement of virtual content in the scene. Core feature of our system is the incorporation of a time-of-flight (TOF-camera device. This device delivers real-time depth images of the environment at a reasonable resolution and quality. This camera is used to build a static environment model and it also allows correct handling of mutual occlusions between real and virtual content, shadow computation and enhanced content planning. The presented system is inexpensive, compact, mobile, flexible and provides convenient calibration procedures. Chroma-keying is replaced by depth-keying which is efficiently performed on the graphics processing unit (GPU by the usage of an environment model and the current ToF-camera image. Automatic extraction and tracking of dynamic scene content is herewith performed and this information is used for planning and alignment of virtual content. An additional sustainable feature is that depth maps of the mixed content are available in real-time, which makes the approach suitable for future 3DTV productions. The presented paper gives an overview of the whole system approach including camera calibration, environment model generation, real-time keying and mixing of virtual and real content, shadowing for virtual content and dynamic object tracking for content planning.

  2. Propagation of Uncertainty in Rigid Body Attitude Flows

    OpenAIRE

    Lee, Taeyoung; Chaturvedi, Nalin A.; Sanyal, Amit K.; Leok, Melvin; McClamroch, N. Harris

    2007-01-01

    Motivated by attitude control and attitude estimation problems for a rigid body, computational methods are proposed to propagate uncertainties in the angular velocity and the attitude. The nonlinear attitude flow is determined by Euler-Poincar\\'e equations that describe the rotational dynamics of the rigid body acting under the influence of an attitude dependent potential and by a reconstruction equation that describes the kinematics expressed in terms of an orthogonal matrix representing the...

  3. 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...

  4. FLIGHT INFORMATION

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Check in With Singapore Airlines, Check out With Paypal Singapore Airlines customers in the United States, Singapore and five other Asia Pacific countries and territories can now pay for their flights with PayPal on singaporeair.com. This facility will progressively be made available to the airline’s customers in up to 17 countries, making this the largest collaboration between PayPal and an Asian carrier to date.

  5. Integrated Flight Performance Analysis of a Launch Abort System Concept

    Science.gov (United States)

    Tartabini, Paul V.

    2007-01-01

    This paper describes initial flight performance analyses conducted early in the Orion Project to support concept feasibility studies for the Crew Exploration Vehicle s Launch Abort System (LAS). Key performance requirements that significantly affect abort capability are presented. These requirements have implications on sizing the Abort Motor, tailoring its thrust profile to meet escape requirements for both launch pad and high drag/high dynamic pressure ascent aborts. Additional performance considerations are provided for the Attitude Control Motor, a key element of the Orion LAS design that eliminates the need for ballast and provides performance robustness over a passive control approach. Finally, performance of the LAS jettison function is discussed, along with implications on Jettison Motor sizing and the timing of the jettison event during a nominal mission. These studies provide an initial understanding of LAS performance that will continue to evolve as the Orion design is matured.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. Wind-Tunnel/Flight Correlation, 1981

    Science.gov (United States)

    Mckinney, L. W. (Editor); Baals, D. D. (Editor)

    1982-01-01

    Wind-tunnel/flight correlation activities are reviewed to assure maximum effectiveness of the early experimental programs of the National Transonic Facility (NTF). Topics included a status report of the NTF, the role of tunnel-to-tunnel correlation, a review of past flight correlation research and the resulting data base, the correlation potential of future flight vehicles, and an assessment of the role of computational fluid dynamics.

  11. Development of Methods for Improved Data Integrity and Efficient Testing of Wind Tunnel Models for Dynamic Test Conditions in Unsteady and Nonlinear Flight Regimes

    OpenAIRE

    Heim, Eugene Henry DeWendt

    2003-01-01

    Todayâ s high performance aircraft are operating in expanded flight envelopes, often maneuvering at high angular rates at high angles-of-attack, even above maximum lift. Current aerodynamic models are inadequate in predicting flight characteristics in the expanded envelope, such as rapid aircraft departures and other unusual motions. Unsteady flows of aircraft are of real concern. The ability to accurately measure aerodynamic loads directly impacts the ability to accurately model and predict...

  12. Magnetometer-only attitude and angular velocity filtering estimation for attitude changing spacecraft

    Science.gov (United States)

    Ma, Hongliang; Xu, Shijie

    2014-09-01

    This paper presents an improved real-time sequential filter (IRTSF) for magnetometer-only attitude and angular velocity estimation of spacecraft during its attitude changing (including fast and large angular attitude maneuver, rapidly spinning or uncontrolled tumble). In this new magnetometer-only attitude determination technique, both attitude dynamics equation and first time derivative of measured magnetic field vector are directly leaded into filtering equations based on the traditional single vector attitude determination method of gyroless and real-time sequential filter (RTSF) of magnetometer-only attitude estimation. The process noise model of IRTSF includes attitude kinematics and dynamics equations, and its measurement model consists of magnetic field vector and its first time derivative. The observability of IRTSF for small or large angular velocity changing spacecraft is evaluated by an improved Lie-Differentiation, and the degrees of observability of IRTSF for different initial estimation errors are analyzed by the condition number and a solved covariance matrix. Numerical simulation results indicate that: (1) the attitude and angular velocity of spacecraft can be estimated with sufficient accuracy using IRTSF from magnetometer-only data; (2) compared with that of RTSF, the estimation accuracies and observability degrees of attitude and angular velocity using IRTSF from magnetometer-only data are both improved; and (3) universality: the IRTSF of magnetometer-only attitude and angular velocity estimation is observable for any different initial state estimation error vector.

  13. Neural Flight Control System

    Science.gov (United States)

    Gundy-Burlet, Karen

    2003-01-01

    The Neural Flight Control System (NFCS) was developed to address the need for control systems that can be produced and tested at lower cost, easily adapted to prototype vehicles and for flight systems that can accommodate damaged control surfaces or changes to aircraft stability and control characteristics resulting from failures or accidents. NFCS utilizes on a neural network-based flight control algorithm which automatically compensates for a broad spectrum of unanticipated damage or failures of an aircraft in flight. Pilot stick and rudder pedal inputs are fed into a reference model which produces pitch, roll and yaw rate commands. The reference model frequencies and gains can be set to provide handling quality characteristics suitable for the aircraft of interest. The rate commands are used in conjunction with estimates of the aircraft s stability and control (S&C) derivatives by a simplified Dynamic Inverse controller to produce virtual elevator, aileron and rudder commands. These virtual surface deflection commands are optimally distributed across the aircraft s available control surfaces using linear programming theory. Sensor data is compared with the reference model rate commands to produce an error signal. A Proportional/Integral (PI) error controller "winds up" on the error signal and adds an augmented command to the reference model output with the effect of zeroing the error signal. In order to provide more consistent handling qualities for the pilot, neural networks learn the behavior of the error controller and add in the augmented command before the integrator winds up. In the case of damage sufficient to affect the handling qualities of the aircraft, an Adaptive Critic is utilized to reduce the reference model frequencies and gains to stay within a flyable envelope of the aircraft.

  14. BeppoSAX attitude operations for GRB follow up

    International Nuclear Information System (INIS)

    This poster describes the attitude dynamics software, Attitude and Orbit Control Ground Support System (AOCGSS), which was developed by TELESPAZIO and integrated in the Operations Control Centre (OCC), in order to support the on ground operations of the Attitude and Orbit Control Subsystem (AOCS). In particular its involvement during the operations performed to carry out the Gamma Ray Burst (GRB) Follow Up is described

  15. Recent Flight Results of the TRMM Kalman Filter

    Science.gov (United States)

    Andrews, Stephen F.; Bilanow, Stephen; Bauer, Frank (Technical Monitor)

    2002-01-01

    The Tropical Rainfall Measuring Mission (TRMM) spacecraft is a nadir pointing spacecraft that nominally controls the roll and pitch attitude based on the Earth Sensor Assembly (ESA) output. TRMM's nominal orbit altitude was 350 km, until raised to 402 km to prolong mission life. During the boost, the ESA experienced a decreasing signal to noise ratio, until sun interference at 393 km altitude made the ESA data unreliable for attitude determination. At that point, the backup attitude determination algorithm, an extended Kalman filter, was enabled. After the boost finished, TRMM reacquired its nadir-pointing attitude, and continued its mission. This paper will briefly discuss the boost and the decision to turn on the backup attitude determination algorithm. A description of the extended Kalman filter algorithm will be given. In addition, flight results from analyzing attitude data and the results of software changes made onboard TRMM will be discussed. Some lessons learned are presented.

  16. Modelling Research on Consumer Attitude Toward Car Brands

    OpenAIRE

    Vlad (Uta) Daniela Steluta

    2014-01-01

    A quantitative research of consumer behaviour usually takes under consideration the following processes: perception, information/ learning, motivation, attitude and actual behaviour. From all this dynamic processes that define consumer behaviour, attitude is the one process relatively stable in time, with a very strong affective and cognitive component. In attempt to model attitude research one need to take under consideration external factors that influence attitude formation as well as this...

  17. Post-Flight Analysis of GPSR Performance During Orion Exploration Flight Test 1

    Science.gov (United States)

    Barker, Lee; Mamich, Harvey; McGregor, John

    2016-01-01

    On 5 December 2014, the first test flight of the Orion Multi-Purpose Crew Vehicle executed a unique and challenging flight profile including an elevated re-entry velocity and steeper flight path angle to envelope lunar re-entry conditions. A new navigation system including a single frequency (L1) GPS receiver was evaluated for use as part of the redundant navigation system required for human space flight. The single frequency receiver was challenged by a highly dynamic flight environment including flight above low Earth orbit, as well as single frequency operation with ionospheric delay present. This paper presents a brief description of the GPS navigation system, an independent analysis of flight telemetry data, and evaluation of the GPSR performance, including evaluation of the ionospheric model employed to supplement the single frequency receiver. Lessons learned and potential improvements will be discussed.

  18. Hierarchical structured robust adaptive attitude controller design for reusable launch vehicles

    Institute of Scientific and Technical Information of China (English)

    Guangxue Yu; Huifeng Li

    2015-01-01

    Reentry attitude control for reusable launch vehicles (RLVs) is chal enging due to the characters of fast nonlinear dy-namics and large flight envelop. A hierarchical structured attitude control system for an RLV is proposed and an unpowered RLV con-trol model is developed. Then, the hierarchical structured control frame consisting of attitude control er, compound control strategy and control al ocation is presented. At the core of the design is a robust adaptive control (RAC) law based on dual loop time-scale separation. A radial basis function neural network (RBFNN) is implemented for compensation of uncertain model dynamics and external disturbances in the inner loop. And then the robust op-timization is applied in the outer loop to guarantee performance robustness. The overal control design frame retains the simplicity in design while simultaneously assuring the adaptive and robust performance. The hierarchical structured robust adaptive con-trol er (HSRAC) incorporates flexibility into the design with regard to control er versatility to various reentry mission requirements. Simulation results show that the improved tracking performance is achieved by means of RAC.

  19. Video Guidance Sensor Flight Experiment Results

    Science.gov (United States)

    Howard, Richard T.; Bryan, Thomas C.; Book, Michael L.

    1998-01-01

    NASA's Marshall Space Flight Center flew on the STS-87 mission an active sensor system, the Video Guidance Sensor (VGS), to demonstrate its functioning in space and to collect performance data. The VGS was designed to provide near-range sensor data as part of an automatic rendezvous and docking system. The sensor determines the relative positions and attitudes between the active sensor and the passive target. The VGS uses laser diodes to illuminate retro-reflectors in the target, a solid-state camera to detect the return from the target, and a frame grabber and digital signal processor to convert the video information into the relative positions and attitudes. The system is designed to operate with the target within a relative azimuth of +/- 9.5 degrees and a relative elevation of +/- 7.5 degrees. The system will acquire and track the target within that field-of-view anywhere from 1.5 meters to 110 meters range, and is designed to acquire at relative attitudes of +/- 10 degrees in pitch and yaw and at any roll angle. The data is output from the sensor at 5 Hz, and the target and sensor software have been designed to permit two independent sensors to operate simultaneously (in order to allow for redundancy). The data from the flight experiment includes raw video data from the VGS camera, relative position and attitude measurements from the VGS to the target, independent hand-held laser ranges from the Shuttle Aft Flight Deck to the target, and Remote Manipulator System position data to correlate with the VGS data. The experiment was quite successful and returned much useful information. The experience gained from the design and flight of this experiment will lead to improved video sensors in the future.

  20. Rover Attitude and Pointing System Simulation Testbed

    Science.gov (United States)

    Vanelli, Charles A.; Grinblat, Jonathan F.; Sirlin, Samuel W.; Pfister, Sam

    2009-01-01

    The MER (Mars Exploration Rover) Attitude and Pointing System Simulation Testbed Environment (RAPSSTER) provides a simulation platform used for the development and test of GNC (guidance, navigation, and control) flight algorithm designs for the Mars rovers, which was specifically tailored to the MERs, but has since been used in the development of rover algorithms for the Mars Science Laboratory (MSL) as well. The software provides an integrated simulation and software testbed environment for the development of Mars rover attitude and pointing flight software. It provides an environment that is able to run the MER GNC flight software directly (as opposed to running an algorithmic model of the MER GNC flight code). This improves simulation fidelity and confidence in the results. Further more, the simulation environment allows the user to single step through its execution, pausing, and restarting at will. The system also provides for the introduction of simulated faults specific to Mars rover environments that cannot be replicated in other testbed platforms, to stress test the GNC flight algorithms under examination. The software provides facilities to do these stress tests in ways that cannot be done in the real-time flight system testbeds, such as time-jumping (both forwards and backwards), and introduction of simulated actuator faults that would be difficult, expensive, and/or destructive to implement in the real-time testbeds. Actual flight-quality codes can be incorporated back into the development-test suite of GNC developers, closing the loop between the GNC developers and the flight software developers. The software provides fully automated scripting, allowing multiple tests to be run with varying parameters, without human supervision.

  1. 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.

  2. Vector magnetometer as an attitude determining instrument

    Science.gov (United States)

    Pietila, R.; Dunn, W. R., Jr.

    1974-01-01

    The solid state vector magnetometer sensor system is presented for the accuracy and reliability of existing systems, and for providing independent measures of attitude. Since a large number of aircraft heading reference systems depend on measurement of the earth's magnetic field, it can be shown that by substituting a 3-axis magnetometer for the remote sensing unit, both heading and attitude measurement functions can be derived using common elements. Sample calculations are made using the earth's magnetic field data acquired during actual flight conditions.

  3. Study on Calculation and Plotting of Dynamic Noise Contour of Single Flight Based on Equivalent Point Swing%单航班噪声动态等值线的绘制算法

    Institute of Scientific and Technical Information of China (English)

    计文斌; 王建东; 杨国庆

    2013-01-01

    机场噪声的可视化是机场范围内环境评价的重要方面,通过机场噪声的等值线分布图可以分析各个时段和地区的噪声大小,并据此调整航班计划和飞行航迹减少受影响地区的噪声强度。基于单飞行事件研究飞机噪声的动态分布情况,利用曲线分段拟合噪声值的变化规律并在此基础上预测实时的噪声值。为了避免常规的等值线绘制中遍历次数多、等值线计算复杂等缺陷,提出一种基于等值点摇摆的等值线网格队列算法,满足了动态绘制对时间复杂度的要求。%Airport noise visualization plays an important role in environmental evaluation of airport region. Through the airport noise contour map, the noise level anytime and anyplace can be analyzed, and the flight plan and flight path can be adjusted to reduce noise intensity in the affected region. In this paper, based on the analysis of aircraft noise dynamic distribution for single flight event, the curve’s piecewise fitting of the noise value was carried out. On this basis the real-time noise value was forecasted. In order to avoid the multiple plotting and the complicated contour computation in the conventional contour computing method, a method of contour grid queue algorithm based on equivalent point swing was proposed. The requirement of time complexity in the dynamic drawing was satisfied.

  4. 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.

  5. 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.

  6. 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. .

  7. Flight of the dragonflies and damselflies.

    Science.gov (United States)

    Bomphrey, Richard J; Nakata, Toshiyuki; Henningsson, Per; Lin, Huai-Ti

    2016-09-26

    This work is a synthesis of our current understanding of the mechanics, aerodynamics and visually mediated control of dragonfly and damselfly flight, with the addition of new experimental and computational data in several key areas. These are: the diversity of dragonfly wing morphologies, the aerodynamics of gliding flight, force generation in flapping flight, aerodynamic efficiency, comparative flight performance and pursuit strategies during predatory and territorial flights. New data are set in context by brief reviews covering anatomy at several scales, insect aerodynamics, neuromechanics and behaviour. We achieve a new perspective by means of a diverse range of techniques, including laser-line mapping of wing topographies, computational fluid dynamics simulations of finely detailed wing geometries, quantitative imaging using particle image velocimetry of on-wing and wake flow patterns, classical aerodynamic theory, photography in the field, infrared motion capture and multi-camera optical tracking of free flight trajectories in laboratory environments. Our comprehensive approach enables a novel synthesis of datasets and subfields that integrates many aspects of flight from the neurobiology of the compound eye, through the aeromechanical interface with the surrounding fluid, to flight performance under cruising and higher-energy behavioural modes.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

  8. Flight of the dragonflies and damselflies.

    Science.gov (United States)

    Bomphrey, Richard J; Nakata, Toshiyuki; Henningsson, Per; Lin, Huai-Ti

    2016-09-26

    This work is a synthesis of our current understanding of the mechanics, aerodynamics and visually mediated control of dragonfly and damselfly flight, with the addition of new experimental and computational data in several key areas. These are: the diversity of dragonfly wing morphologies, the aerodynamics of gliding flight, force generation in flapping flight, aerodynamic efficiency, comparative flight performance and pursuit strategies during predatory and territorial flights. New data are set in context by brief reviews covering anatomy at several scales, insect aerodynamics, neuromechanics and behaviour. We achieve a new perspective by means of a diverse range of techniques, including laser-line mapping of wing topographies, computational fluid dynamics simulations of finely detailed wing geometries, quantitative imaging using particle image velocimetry of on-wing and wake flow patterns, classical aerodynamic theory, photography in the field, infrared motion capture and multi-camera optical tracking of free flight trajectories in laboratory environments. Our comprehensive approach enables a novel synthesis of datasets and subfields that integrates many aspects of flight from the neurobiology of the compound eye, through the aeromechanical interface with the surrounding fluid, to flight performance under cruising and higher-energy behavioural modes.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'. PMID:27528779

  9. Efficient Global Aerodynamic Modeling from Flight Data

    Science.gov (United States)

    Morelli, Eugene A.

    2012-01-01

    A method for identifying global aerodynamic models from flight data in an efficient manner is explained and demonstrated. A novel experiment design technique was used to obtain dynamic flight data over a range of flight conditions with a single flight maneuver. Multivariate polynomials and polynomial splines were used with orthogonalization techniques and statistical modeling metrics to synthesize global nonlinear aerodynamic models directly and completely from flight data alone. Simulation data and flight data from a subscale twin-engine jet transport aircraft were used to demonstrate the techniques. Results showed that global multivariate nonlinear aerodynamic dependencies could be accurately identified using flight data from a single maneuver. Flight-derived global aerodynamic model structures, model parameter estimates, and associated uncertainties were provided for all six nondimensional force and moment coefficients for the test aircraft. These models were combined with a propulsion model identified from engine ground test data to produce a high-fidelity nonlinear flight simulation very efficiently. Prediction testing using a multi-axis maneuver showed that the identified global model accurately predicted aircraft responses.

  10. 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.

  11. The Submillimeter Wave Astronomy Satellite Attitude Control Software Design

    OpenAIRE

    Anderson, Mark; Wennersten, Miriam; Bonnett, Joseph; Hill, Adrian

    1995-01-01

    The Submilimeter Wave Astronomy Satellite (SWAS) was selected for flight by NASA in 1989 as a part of the Small Explorer (SMEX) program. SWAS's primary science objective is to conduct high spectral resolution surveys of galactic molecular clouds. The SWAS Attitude Control System (ACS) is three-axis controlled, zero momentum stabilized, and is capable of performing subarcminute pointing. This paper will discuss the design of the software components which comprise the Attitude Control System So...

  12. Integrative Model of Drosophila Flight

    OpenAIRE

    Dickson, William B.; Andrew D Straw; Dickinson, Michael H

    2008-01-01

    This paper presents a framework for simulating the flight dynamics and control strategies of the fruit fly Drosophila melanogaster. The framework consists of five main components: an articulated rigid-body simulation, a model of the aerodynamic forces and moments, a sensory systems model, a control model, and an environment model. In the rigid-body simulation the fly is represented by a system of three rigid bodies connected by a pair of actuated ball joints. At each instant of th...

  13. Low Speed Avian Maneuvering Flight

    OpenAIRE

    Ros, Ivo

    2013-01-01

    Low speed avian maneuvering flight is an ecologically crucial behavior that has contributed to the explosive diversification of several avian taxa by allowing access to complex spatial environments. Negotiating a sharp aerial turn requires finely tuned interactions between an animal's sensory-motor system and its environment. My thesis work focuses on how aerodynamic forces, wing and body dynamics, and sensory feedback interact during aerial turning in the pigeon (Columba livea).

  14. Analysis of Effects on Alignment in Dynamic State Precision of Warship Combat System Caused by Its Attitude%舰艇姿态对作战系统动态对准精度的影响分析

    Institute of Scientific and Technical Information of China (English)

    周志恒; 赵建军; 桑德一; 杨利斌

    2016-01-01

    为提高舰艇作战系统动态对准精度,笔者以舰载三坐标雷达为例,研究了舰艇姿态对作战系统动态对准精度的影响。建立了作战系统对准的坐标系,推导了其中主要的坐标转换,计算了舰艇姿态引起的传感器测量误差,分析了舰艇摇摆对动态对准精度的影响,并进行仿真实验。仿真结果表明:舰艇艏摇角造成了传感器测量的方位角误差,舰艇的纵摇角、横摇角造成了传感器测量的方位角和俯仰角误差,但舰艇姿态对传感器的距离测量影响较小。需要在后续的动态对准数据处理过程中对误差进行修正,从而满足舰艇作战系统动态对准的要求。%In order to improve the accuracy of warship combat system alignment in dynamic state, the author has taken shipborne 3D radar as an example to study the effects on alignment in dynamic state of warship combat system caused by its attitude. A coordinate system aligned combat system was established in this paper, the mainly coordinate conversion were derived, sensor measurement errors caused by warship's attitude were calculated and simulated by computer. Simulation results show that: the warship's heading angle causes the azimuth angle error of sensor measurements, the warship's pitch angle, roll angle cause the angle azimuth and elevation angle error of sensor measurements, and there is almost no influence on sensor distance measurement caused by warship's attitude. Error correction is need in the subsequent data processing of dynamic alignment to meet the requirements of warship combat system alignment in dynamic state.

  15. 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.

  16. 基于动态逆的动力翼伞自主飞行控制方法%Autonomous Flight Control Method of Powered Paraglider Based on Dynamic: Inversion

    Institute of Scientific and Technical Information of China (English)

    钱克昌; 陈自力; 李建

    2011-01-01

    To the problem that the accurate mathematic model of powered paraghder (PPG) can hardly be got, and the flight control system of PPG is a complicated nonlinear system, adynamic model of PPG with 8-DOF is built A dynamic neural network consisting of the static neural network and the integrators is designed.And the control method of dynamic inversion is used for PPG, based on the ap pproximation property of neural network and dynamic inversion.Sinmulation results show that the proposed method strong ability of control and robustness, possessing better application value in autonomous flight control of PPG.%针对动力翼伞精确数学模型难以获得,系统输入输出关系耦合复杂等特点,建立动力翼伞8自由度动力学模型,设计由静态神经网络和积分器组成的动态神经网络,利用神经网络的逼近能力和动态逆控制方法相结合,提出了基于神经网络动态逆方法的动力翼伞控制方案,并进行了飞行仿真验证,结果表明完全满足控制要求,具有较好的抗干扰能和鲁棒性能,对于实现动力翼伞的自主飞行控制具有很好的应用价值.

  17. Flight instructors’ perceptions of pilot behaviour related to gender

    Directory of Open Access Journals (Sweden)

    Leopold P. Vermeulen

    2009-04-01

    Full Text Available This study investigated flight instructors’ perceptions with regard to gender-related pilot behaviour. The subjects fell into two sample groups. The first sample consisted of 93 flight instructors and the second sample was a control group of 93 commercial pilots. The Aviation Gender Attitude Questionnaire (AGAQ was administered to measure the perceptions that both groups held about female pilots’ flying proficiency and safety orientation. Statistical analysis revealed that flight instructors and commercial pilots differed significantly in their perceptions of female pilots’ flying proficiency but that the two groups did not differ in their perceptions of female pilots’ safety orientation.

  18. 14 CFR 91.109 - Flight instruction; Simulated instrument flight and certain flight tests.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Flight instruction; Simulated instrument flight and certain flight tests. 91.109 Section 91.109 Aeronautics and Space FEDERAL AVIATION... OPERATING AND FLIGHT RULES Flight Rules General § 91.109 Flight instruction; Simulated instrument flight...

  19. Comparison of induced velocity models for helicopter flight mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.E.; Houston, S.S.

    2002-07-01

    Modeling of rotor-induced velocity receives continued attention in the literature as the rotorcraft community addresses limitations in the fidelity of simulations of helicopter stability, control, and handling qualities. A comparison is presented of results obtained using a rigid-blade rotor-fuselage model configured with two induced velocity models: a conventional, first-order, finite state, dynamic inflow model and a wake model that solves a vorticity transport equation on a computational mesh enclosing the rotorcraft. Differences between the two models are quantified by comparing predictions of trimmed rotor blade flap, lag and feather angles, airframe pitch and roll attitudes, cross-coupling derivatives, response to control inputs, and airframe vibration. Results are presented in the context of measurements taken on a Puma aircraft in steady flight from hover to high speed. More accurate predictions of the cross-coupling derivatives, response to control, and airframe vibration obtained using the vorticity transport model suggest that incorporation of real flowfield effects is important to extending the bandwidth of applicability of helicopter simulation models. Unexpectedly small differences in some of the trim predictions obtained using the two wake models suggest that an overall improvement in simulation fidelity may not be achieved without equivalent attention to the rotor dynamic model. (Author)

  20. 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...

  1. Control Of Flexible Structures-2 (COFS-2) flight control, structure and gimbal system interaction study

    Science.gov (United States)

    Fay, Stanley; Gates, Stephen; Henderson, Timothy; Sackett, Lester; Kirchwey, Kim; Stoddard, Isaac; Storch, Joel

    1988-01-01

    The second Control Of Flexible Structures Flight Experiment (COFS-2) includes a long mast as in the first flight experiment, but with the Langley 15-m hoop column antenna attached via a gimbal system to the top of the mast. The mast is to be mounted in the Space Shuttle cargo bay. The servo-driven gimbal system could be used to point the antenna relative to the mast. The dynamic interaction of the Shuttle Orbiter/COFS-2 system with the Orbiter on-orbit Flight Control System (FCS) and the gimbal pointing control system has been studied using analysis and simulation. The Orbiter pointing requirements have been assessed for their impact on allowable free drift time for COFS experiments. Three fixed antenna configurations were investigated. Also simulated was Orbiter attitude control behavior with active vernier jets during antenna slewing. The effect of experiment mast dampers was included. Control system stability and performance and loads on various portions of the COFS-2 structure were investigated. The study indicates possible undesirable interaction between the Orbiter FCS and the flexible, articulated COFS-2 mast/antenna system, even when restricted to vernier reaction jets.

  2. Integrated primary flight display: the sky arc

    Science.gov (United States)

    Voulgaris, Theodore J.; Metalis, Sam A.; Mobley, R. S.

    1995-05-01

    Flight instrument interpretability has been a key piloting issue because it is directly related to operator performance and inversely related to operator error. To improve interpretability we have developed the Sky Arc, a new symbology initially developed for attitude control, particularly for a helmet-mounted display. It consists of an integrated set of graphic symbols which vary in a continuous, analog fashion with changing flight parameters. The Sky Arc currently integrates, pitch, roll, heading, air speed, and terrain avoidance. The display can be integrated into a head down display, a head up display, or a helmet mounted display. In this preliminary study the usability of the Sky Arc as an attitude indicator was compared to a conventional head-up display pitch ladder symbology. The test involved six test subject pilots and a medium-fidelity simulator. The pilots were asked to fully recover from a series of unusual attitude conditions that were presented on the simulator. The time taken to recover and the correctness of the recovery procedure served as the objective evaluation measures. A Likert-type rating scale and open-ended subject matter expert opinions served as the subjective measures of evaluation. To examine whether there was a relationship between usability of the attitude indicator and difficulty of the unusual attitude, the workload levels involved in performing the unusual attitude recoveries were grouped into three levels, low, medium, and high. At each workload level there were four conditions, for a total of 12 different conditions. Each pilot was asked to recovery twice from each condition, for a total of 24 unusual attitude recovery trials. The test trials were counterbalanced and displayed in a prearranged order. No differences due to difficulty of the unusual attitude were detected. Overall, the study revealed that the Sky Arc led to generally faster recoveries than did the standard display, as well as higher subjective preference ratings

  3. Flight of the dragonflies and damselflies

    Science.gov (United States)

    Nakata, Toshiyuki; Henningsson, Per; Lin, Huai-Ti

    2016-01-01

    This work is a synthesis of our current understanding of the mechanics, aerodynamics and visually mediated control of dragonfly and damselfly flight, with the addition of new experimental and computational data in several key areas. These are: the diversity of dragonfly wing morphologies, the aerodynamics of gliding flight, force generation in flapping flight, aerodynamic efficiency, comparative flight performance and pursuit strategies during predatory and territorial flights. New data are set in context by brief reviews covering anatomy at several scales, insect aerodynamics, neuromechanics and behaviour. We achieve a new perspective by means of a diverse range of techniques, including laser-line mapping of wing topographies, computational fluid dynamics simulations of finely detailed wing geometries, quantitative imaging using particle image velocimetry of on-wing and wake flow patterns, classical aerodynamic theory, photography in the field, infrared motion capture and multi-camera optical tracking of free flight trajectories in laboratory environments. Our comprehensive approach enables a novel synthesis of datasets and subfields that integrates many aspects of flight from the neurobiology of the compound eye, through the aeromechanical interface with the surrounding fluid, to flight performance under cruising and higher-energy behavioural modes. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight’. PMID:27528779

  4. White flight or flight from poverty?

    CERN Document Server

    Jego, C; Jego, Charles; Roehner, Bertrand M.

    2006-01-01

    The phenomenon of White flight is often illustrated by the case of Detroit whose population dropped from 1.80 million to 0.95 million between 1950 and 2000 while at the same time its Black and Hispanic component grew from 30 percent to 85 percent. But is this case really representative? The present paper shows that the phenomenon of White flight is in fact essentially a flight from poverty. As a confirmation, we show that the changes in White or Black populations are highly correlated which means that White flight is always paralleled by Black flight (and Hispanic flight as well). This broader interpretation of White flight accounts not only for the case of northern cities such as Cincinnati, Cleveland or Detroit, but for all population changes at county level, provided the population density is higher than a threshold of about 50 per square-kilometer which corresponds to moderately urbanized areas (as can be found in states like Indiana or Virginia for instance).

  5. Flight variability in the woodwasp Sirex noctilio (Hymenoptera: Siricidae): an analysis of flight data using wavelets.

    Science.gov (United States)

    Bruzzone, Octavio A; Villacide, José M; Bernstein, Carlos; Corley, Juan C

    2009-03-01

    We describe flight variability in the woodwasp Sirex noctilio Fabricius, 1793 (Hymenoptera: Siricidae) by studying tethered females in a flight mill device and analyzing output data by a time series methodology. Twenty-eight wasps were flown during 24 h-long periods, under controlled temperature and lighting conditions. The maximum distance recorded was 49 km, and mean velocity was 0.37 m s(-1). All wasps lost weight during flight (mean weight loss of 10.0% of initial body mass). By using a wavelets analysis on the flight mill time series output, we identified three distinct flight patterns: regular (long acceleration-deceleration spells), periodic (alternation of acceleration-deceleration spells without resting) and pulsating (resting spells interrupted by bursts of flight activity). The first two flight patterns are indistinguishable using traditional flight mill data analysis. Flight patterns for each individual were significantly dependent on wasp body mass, suggesting a relationship with the resources used in flight and their availability. Large females flew sequentially through a regular-periodic-pulsating sequence but medium sized wasps flew mostly with periodic and pulsating patterns. The smallest wasps flew only in a pulsating pattern, being incapable of long, sustained flight. Variability in size and behavior can have significant consequences on population dynamics by determining local and regional dispersal. An important outcome of our work is the introduction of wavelet analysis to study tethered flight data series for the first time. This methodology allowed us to uncover and statistically test individual variability in insect flight characteristics. PMID:19218525

  6. Magnetospheric Multiscale (MMS) Mission Attitude Ground System Design

    Science.gov (United States)

    Sedlak, Joseph E.; Superfin, Emil; Raymond, Juan C.

    2011-01-01

    This paper presents an overview of the attitude ground system (AGS) currently under development for the Magnetospheric Multiscale (MMS) mission. The primary responsibilities for the MMS AGS are definitive attitude determination, validation of the onboard attitude filter, and computation of certain parameters needed to improve maneuver performance. For these purposes, the ground support utilities include attitude and rate estimation for validation of the onboard estimates, sensor calibration, inertia tensor calibration, accelerometer bias estimation, center of mass estimation, and production of a definitive attitude history for use by the science teams. Much of the AGS functionality already exists in utilities used at NASA's Goddard Space Flight Center with support heritage from many other missions, but new utilities are being created specifically for the MMS mission, such as for the inertia tensor, accelerometer bias, and center of mass estimation. Algorithms and test results for all the major AGS subsystems are presented here.

  7. 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.

  8. Nurses' Attitudes towards Alcoholics.

    Science.gov (United States)

    Speer, Rita D.

    Nurses' attitudes toward the alcoholic can have a profound impact on the person suffering from alcoholism. These attitudes can affect the alcoholic's care and even whether the alcoholic chooses to recover. This study investigated attitudes of approximately 68 nurses employed in hospitals, 49 nurses in treatment facilities, 58 nursing students, and…

  9. 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.

  10. Thermal biology of flight in a butterfly: genotype, flight metabolism, and environmental conditions.

    Science.gov (United States)

    Mattila, Anniina L K

    2015-12-01

    Knowledge of the effects of thermal conditions on animal movement and dispersal is necessary for a mechanistic understanding of the consequences of climate change and habitat fragmentation. In particular, the flight of ectothermic insects such as small butterflies is greatly influenced by ambient temperature. Here, variation in body temperature during flight is investigated in an ecological model species, the Glanville fritillary butterfly (Melitaea cinxia). Attention is paid on the effects of flight metabolism, genotypes at candidate loci, and environmental conditions. Measurements were made under a natural range of conditions using infrared thermal imaging. Heating of flight muscles by flight metabolism has been presumed to be negligible in small butterflies. However, the results demonstrate that Glanville fritillary males with high flight metabolic rate maintain elevated body temperature better during flight than males with a low rate of flight metabolism. This effect is likely to have a significant influence on the dispersal performance and fitness of butterflies and demonstrates the possible importance of intraspecific physiological variation on dispersal in other similar ectothermic insects. The results also suggest that individuals having an advantage in low ambient temperatures can be susceptible to overheating at high temperatures. Further, tolerance of high temperatures may be important for flight performance, as indicated by an association of heat-shock protein (Hsp70) genotype with flight metabolic rate and body temperature at takeoff. The dynamics of body temperature at flight and factors affecting it also differed significantly between female and male butterflies, indicating that thermal dynamics are governed by different mechanisms in the two sexes. This study contributes to knowledge about factors affecting intraspecific variation in dispersal-related thermal performance in butterflies and other insects. Such information is needed for predictive

  11. Thermal biology of flight in a butterfly: genotype, flight metabolism, and environmental conditions.

    Science.gov (United States)

    Mattila, Anniina L K

    2015-12-01

    Knowledge of the effects of thermal conditions on animal movement and dispersal is necessary for a mechanistic understanding of the consequences of climate change and habitat fragmentation. In particular, the flight of ectothermic insects such as small butterflies is greatly influenced by ambient temperature. Here, variation in body temperature during flight is investigated in an ecological model species, the Glanville fritillary butterfly (Melitaea cinxia). Attention is paid on the effects of flight metabolism, genotypes at candidate loci, and environmental conditions. Measurements were made under a natural range of conditions using infrared thermal imaging. Heating of flight muscles by flight metabolism has been presumed to be negligible in small butterflies. However, the results demonstrate that Glanville fritillary males with high flight metabolic rate maintain elevated body temperature better during flight than males with a low rate of flight metabolism. This effect is likely to have a significant influence on the dispersal performance and fitness of butterflies and demonstrates the possible importance of intraspecific physiological variation on dispersal in other similar ectothermic insects. The results also suggest that individuals having an advantage in low ambient temperatures can be susceptible to overheating at high temperatures. Further, tolerance of high temperatures may be important for flight performance, as indicated by an association of heat-shock protein (Hsp70) genotype with flight metabolic rate and body temperature at takeoff. The dynamics of body temperature at flight and factors affecting it also differed significantly between female and male butterflies, indicating that thermal dynamics are governed by different mechanisms in the two sexes. This study contributes to knowledge about factors affecting intraspecific variation in dispersal-related thermal performance in butterflies and other insects. Such information is needed for predictive

  12. Wind-tunnel based definition of the AFE aerothermodynamic environment. [Aeroassist Flight Experiment

    Science.gov (United States)

    Miller, Charles G.; Wells, W. L.

    1992-01-01

    The Aeroassist Flight Experiment (AFE), scheduled to be performed in 1994, will serve as a precursor for aeroassisted space transfer vehicles (ASTV's) and is representative of entry concepts being considered for missions to Mars. Rationale for the AFE is reviewed briefly as are the various experiments carried aboard the vehicle. The approach used to determine hypersonic aerodynamic and aerothermodynamic characteristics over a wide range of simulation parameters in ground-based facilities is presented. Facilities, instrumentation and test procedures employed in the establishment of the data base are discussed. Measurements illustrating the effects of hypersonic simulation parameters, particularly normal-shock density ratio (an important parameter for hypersonic blunt bodies), and attitude on aerodynamic and aerothermodynamic characteristics are presented, and predictions from computational fluid dynamic (CFD) computer codes are compared with measurement.

  13. A Heading and Flight-Path Angle Control of Aircraft Based on Required Acceleration Vector

    Science.gov (United States)

    Yoshitani, Naoharu

    This paper describes a control of heading and flight-path angles of aircraft to time-varying command angles. The controller first calculates an acceleration command vector (acV), which is vertical to the velocity vector. acV consists of two components; the one is feedforward acceleration obtained from the rates of command angles, and the other is feedback acceleration obtained from angle deviations by using PID control law. A bank angle command around the velocity vector and commands of pitch and yaw rates are then obtained to generate the required acceleration. A roll rate command is calculated from bank angle deviation. Roll, pitch and yaw rate commands are put into the attitude controller, which can be composed of any suitable control laws such as PID control. The control requires neither aerodynamic coefficients nor online calculation of the inverse dynamics of the aircraft. A numerical simulation illustrates the effects of the control.

  14. Attitude Controller-Observer Design for the NTNU Test Satellite

    OpenAIRE

    Alvenes, Fredrik

    2013-01-01

    This report presents the results from the development and design of an Attitude Controller-Observer for the NTNU Test Satellite (NUTS). It gives an insight to mathematical modeling of satellite attitude dynamics for 3 degrees of freedom. By the different limitations of how the NUTS operates, these models are adjusted accordingly.A strategy for controlling the attitude is presented. Through an explanation of the magnetic actuators, the control laws are also adapted to work with the NUTS satell...

  15. Wavelet Applications for Flight Flutter Testing

    Science.gov (United States)

    Lind, Rick; Brenner, Marty; Freudinger, Lawrence C.

    1999-01-01

    Wavelets present a method for signal processing that may be useful for analyzing responses of dynamical systems. This paper describes several wavelet-based tools that have been developed to improve the efficiency of flight flutter testing. One of the tools uses correlation filtering to identify properties of several modes throughout a flight test for envelope expansion. Another tool uses features in time-frequency representations of responses to characterize nonlinearities in the system dynamics. A third tool uses modulus and phase information from a wavelet transform to estimate modal parameters that can be used to update a linear model and reduce conservatism in robust stability margins.

  16. 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 neutro...... of disordered surface spins and vibrations of individual nanoparticles. (C) 2004 Elsevier B.V. All rights reserved....

  17. Initial Satellite Formation Flight Results from the Magnetospheric Multiscale Mission

    Science.gov (United States)

    Williams, Trevor; Ottenstein, Neil; Palmer, Eric; Farahmand, Mitra

    2016-01-01

    This paper will describe the results that have been obtained to date concerning MMS formation flying. The MMS spacecraft spin at a rate of 3.1 RPM, with spin axis roughly aligned with Ecliptic North. Several booms are used to deploy instruments: two 5 m magnetometer booms in the spin plane, two rigid booms of length 12.5 m along the positive and negative spin axes, and four flexible wire booms of length 60 m in the spin plane. Minimizing flexible motion of the wire booms requires that reorientation of the spacecraft spin axis be kept to a minimum: this is limited to attitude maneuvers to counteract the effects of gravity-gradient and apparent solar motion. Orbital maneuvers must therefore be carried out in essentially the nominal science attitude. These burns make use of a set of monopropellant hydrazine thrusters: two (of thrust 4.5 N) along the spin axis in each direction, and eight (of thrust 18 N) in the spin plane; the latter are pulsed at the spin rate to produce a net delta-v. An on-board accelerometer-based controller is used to accurately generate a commanded delta-v. Navigation makes use of a weak-signal GPS-based system: this allows signals to be received even when MMS is flying above the GPS orbits, producing a highly accurate determination of the four MMS orbits. This data is downlinked to the MMS Mission Operations Center (MOC) and used by the MOC Flight Dynamics Operations Area (FDOA) for maneuver design. These commands are then uplinked to the spacecraft and executed autonomously using the controller, with the ground monitoring the burns in real time.

  18. Fundamentals of spacecraft attitude determination and control

    CERN Document Server

    Markley, F Landis

    2014-01-01

    This book explores topics that are central to the field of spacecraft attitude determination and control. The authors provide rigorous theoretical derivations of significant algorithms accompanied by a generous amount of qualitative discussions of the subject matter. The book documents the development of the important concepts and methods in a manner accessible to practicing engineers, graduate-level engineering students and applied mathematicians. It includes detailed examples from actual mission designs to help ease the transition from theory to practice, and also provides prototype algorithms that are readily available on the author’s website. Subject matter includes both theoretical derivations and practical implementation of spacecraft attitude determination and control systems. It provides detailed derivations for attitude kinematics and dynamics, and provides detailed description of the most widely used attitude parameterization, the quaternion. This title also provides a thorough treatise of attitu...

  19. The development and demonstration of hybrid programmable attitude control electronics

    Science.gov (United States)

    Smith, L. S.; Kopf, E. H., Jr.

    1973-01-01

    In the course of extended life attitude control system (ELACS) research sponsored by NASA a hybrid programable attitude control electronics (HYPACE) concept was developed and demonstrated. The wide variety of future planetary missions demanded a new control approach to accommodate the automatic fault tolerance and long the life requirements of such missions. HYPACE provides an adaptable, analog/digital design approach that permits preflight and in-flight accommodation of mission changes, component performance variations, and spacecraft changes, through programing. This enabled broad multimission flexibility of application in a cost effective manner. Previously, flight control computers have not been not flown on planetary missions because of weight and power problems. These problems were resolved in the design of HYPACE. The HYPACE design, which was demonstrated in breadboard form on a single-axis gas-bearing spacecraft simulation, uses a single control channel to perform the attitude control functions sequentially, thus significantly reducing the number of component parts over hard-wired designs.

  20. 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.

  1. 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.

  2. 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....

  3. Flight Control Design for a Tailless Aircraft Using Eigenstructure Assignment

    OpenAIRE

    Clara Nieto-Wire; Kenneth Sobel

    2011-01-01

    We apply eigenstructure assignment to the design of a flight control system for a wind tunnel model of a tailless aircraft. The aircraft, known as the innovative control effectors (ICEs) aircraft, has unconventional control surfaces plus pitch and yaw thrust vectoring. We linearize the aircraft in straight and level flight at an altitude of 15,000 feet and Mach number 0.4. Then, we separately design flight control systems for the longitudinal and lateral dynamics. We use a control allocation ...

  4. ER-2 in flight

    Science.gov (United States)

    1996-01-01

    In this film clip, we see an ER-2 on its take off roll and climb as it departs from runway 22 at Edwards AFB, California. In 1981, NASA acquired its first ER-2 aircraft. The agency obtained a second ER-2 in 1989. These airplanes replaced two Lockheed U-2 aircraft, which NASA had used to collect scientific data since 1971. The U-2, and later the ER-2, were based at the Ames Research Center, Moffett Field, California, until 1997. In 1997, the ER-2 aircraft and their operations moved to NASA Dryden Flight Research Center, Edwards, California. Since the inaugural flight for this program, August 31, 1971, NASA U-2 and ER-2 aircraft have flown more than 4,000 data missions and test flights in support of scientific research conducted by scientists from NASA, other federal agencies, states, universities, and the private sector. NASA is currently using two ER-2 Airborne Science aircraft as flying laboratories. The aircraft, based at NASA Dryden, collect information about our surroundings, including Earth resources, celestial observations, atmospheric chemistry and dynamics, and oceanic processes. The aircraft also are used for electronic sensor research and development, satellite calibration, and satellite data validation. The ER-2 is a versatile aircraft well-suited to perform multiple mission tasks. It is 30 percent larger than the U-2 with a 20 feet longer wingspan and a considerably increased payload over the older airframe. The aircraft has four large pressurized experiment compartments and a high-capacity AC/DC electrical system, permitting it to carry a variety of payloads on a single mission. The modular design of the aircraft permits rapid installation or removal of payloads to meet changing mission requirements. The ER-2 has a range beyond 3,000 miles (4800 kilometers); is capable of long flight duration and can operate at altitudes up to 70,000 feet (21.3 kilometers) if required. Operating at an altitude of 65,000 feet (19.8 kilometers) the ER-2 acquires data

  5. Design for robustness using the μ-synthesis applied to launcher attitude and vibration control

    Science.gov (United States)

    Morita, Yasuhiro; Goto, Shinichi

    2008-01-01

    The M-V launch vehicle of Japan Aerospace Exploration Agency (JAXA) has successfully injected Japan's fifth X-ray space telescope "SUZAKU" into its low earth orbit in this past July. The attitude and vibration control algorithm of the M-V rocket used to be highlighted by its H∞ robust stability since its first flight conducted in 1997. Beyond this, its robustness character has been further enhanced using the μ-synthesis approach to get better robust characteristics not only in stability but in tracking performance under uncertainty of the system dynamics. The performance has been validated by the latest back-to-back successful flights of the vehicle: in May 2003 to directly inject Japan's first asteroid sample return spaceship "HAYABUSA" into the planned inter-planetary trajectory and in this past July to launch the telescope. The μ-synthesis has been applied for the first time ever for Japan's launcher control beyond the reliable H∞ design. The plant dynamics has an extremely high-order and unstable characteristics, thus the standard μ-synthesis format cannot be directly applied. The paper gives a unique methodology to apply the theory to such a real high-order complicated system.

  6. Deploying process modeling and attitude control of a satellite with a large deployable antenna

    OpenAIRE

    Zhigang Xing; Gangtie Zheng

    2014-01-01

    Modeling and attitude control methods for a satellite with a large deployable antenna are studied in the present paper. Firstly, for reducing the model dimension, three dynamic models for the deploying process are developed, which are built with the methods of multi-rigid-body dynamics, hybrid coordinate and substructure. Then an attitude control method suitable for the deploying process is proposed, which can keep stability under any dynamical parameter variation. Subsequently, this attitude...

  7. Surface tension dominates insect flight on fluid interfaces.

    Science.gov (United States)

    Mukundarajan, Haripriya; Bardon, Thibaut C; Kim, Dong Hyun; Prakash, Manu

    2016-03-01

    Flight on the 2D air-water interface, with body weight supported by surface tension, is a unique locomotion strategy well adapted for the environmental niche on the surface of water. Although previously described in aquatic insects like stoneflies, the biomechanics of interfacial flight has never been analysed. Here, we report interfacial flight as an adapted behaviour in waterlily beetles (Galerucella nymphaeae) which are also dexterous airborne fliers. We present the first quantitative biomechanical model of interfacial flight in insects, uncovering an intricate interplay of capillary, aerodynamic and neuromuscular forces. We show that waterlily beetles use their tarsal claws to attach themselves to the interface, via a fluid contact line pinned at the claw. We investigate the kinematics of interfacial flight trajectories using high-speed imaging and construct a mathematical model describing the flight dynamics. Our results show that non-linear surface tension forces make interfacial flight energetically expensive compared with airborne flight at the relatively high speeds characteristic of waterlily beetles, and cause chaotic dynamics to arise naturally in these regimes. We identify the crucial roles of capillary-gravity wave drag and oscillatory surface tension forces which dominate interfacial flight, showing that the air-water interface presents a radically modified force landscape for flapping wing flight compared with air.

  8. Flight muscle shape reliably predicts flight muscle mass of migratory songbirds: a new tool for field ornithologists

    OpenAIRE

    Bauchinger, Ulf; McWilliams, Scott R.; Kolb, Harald; Popenko, Vladimir M.; Price, Edwin R.; Biebach, Herbert

    2011-01-01

    Abstract The pectoral muscle is the biggest organ within a passerine bird. It provides flight locomotion and is known to act as a protein source during periods with increased protein demands or decreased protein availability. The mass of the flight muscle is dynamic and changes during juvenile growth, reproduction, seasonal acclimatization, fasting and migration. Thus, a tool that accurately and non-invasively quantifies this phenotypic flexibility in flight muscle mass is of inter...

  9. 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.

  10. Resonance enhanced multiphoton ionization time-of-flight (REMPI-TOF) study of phosphorous oxychloride (POCl3) dissociation at 235 nm: Dynamics of Cl(2Pj) formation

    International Nuclear Information System (INIS)

    Highlights: ► First results on dynamics of Cl atom formation in the photodissociation of POCl3. ► Two types of Cl atom formation mechanism. ► Cl2 formation from the ground state supported by ab initio calculation. -- Abstract: In one-color REMPI-TOF experiment, the photodissociation dynamics of POCl3 has been studied by photolyzing POCl3 and probing the chlorine atom photofragments, namely, Cl(2P3/2) and Cl∗(2P1/2) using 2 + 1 REMPI scheme, in the 234–236 nm region. We have determined the centre-of-mass photofragment speed distribution, recoil anisotropy parameter, and the spin–orbit branching ratio for chlorine atom elimination channels. The anisotropy parameters for Cl and Cl∗ are the same, and characterized by a value of 0.0 ± 0.05. Two components, namely, the fast and the slow, are observed in the translational energy distributions of Cl and Cl∗. The average translational energies for the Cl and Cl∗ channels for the fast components are 12.5 ± 1.5 and 16.8 ± 1.5 kcal/mol, while, for the slow components, the average translational energies are 1.5 ± 1.0 and 2.5 ± 1.0 kcal/mol, respectively. Apart from the chlorine atom elimination channel, Cl2 elimination is also observed in the photodissociation of POCl3.

  11. Java for flight software

    Science.gov (United States)

    Benowitz, E.; Niessner, A.

    2003-01-01

    This work involves developing representative mission-critical spacecraft software using the Real-Time Specification for Java (RTSJ). This work currently leverages actual flight software used in the design of actual flight software in the NASA's Deep Space 1 (DSI), which flew in 1998.

  12. 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.

  13. 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

  14. Cockpit management attitudes.

    Science.gov (United States)

    Helmreich, R L

    1984-10-01

    Distinctions are drawn between personality traits and attitudes. The stability of the personality and the malleability of attitudes are stressed. These concepts are related to pilot performance, especially in the areas of crew coordination and cockpit resource management. Airline pilots were administered a Cockpit Management Attitudes questionnaire; empirical data from that survey are reported and implications of the data for training in crew coordination are discussed.

  15. Thermal Energy Storage Flight Experiment in Microgravity

    Science.gov (United States)

    Namkoong, David

    1992-01-01

    The Thermal Energy Storage Flight Experiment was designed to characterize void shape and location in LiF-based phase change materials in different energy storage configurations representative of advanced solar dynamic systems. Experiment goals and payload design are described in outline and graphic form.

  16. IDENTIFICATION OF GYRO DRIFTS UNDER THREE AXIS ATTITUDE COUPLING

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Optical gyros and star sensors are primary measurement hardware in an attitude control system with high accuracy.The drifts of the optical gyros, however, make an unfavorable impact on the accuracy of the attitude control system.In order for compensations to be provided, this paper presents a least-square method to identify the optical gyro drifts by using flight attitude data from the star sensors and the optical gyros.Equations for identification are formulated by quaternion.Integration of the identification equations and the data from the star sensors are utilized to form a least-square index, in which lower sampling frequency of the star sensors than that of the optical gyros is dealt with effectively.An iterative identification algorithm is presented to minimize the index.Identification procedure under three-axis attitude coupling is illustrated .Simulation results show the effectiveness of the method presented.Proper sample size and sampling frequency are also recommended.

  17. 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.

  18. 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.

  19. ATTITUDE OF STUDENT TEACHERS TOWARDS TEACHING PROFESSION

    Directory of Open Access Journals (Sweden)

    Anupama BHARGAVA

    2014-07-01

    Full Text Available 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 learning of the students. Attitude being a social construct is influenced by many factors like gender social strata ,age, stream of education and previous experience of the job .what bearing the gender and stream of education has on the attitude of student teachers towards teaching profession to throw light on this a study was conducted using a readymade tool. Study of different categories like Non-tribal male and female science stream, nontribal male and female social science stream, Tribal male and female science stream, Tribal male and female social science stream was undertaken. In a sample of hundred students ninety six students responded. The mean scores were considered and ‘ t’ value was calculated to find the difference in the attitude of different categories towards teaching profession.

  20. 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...

  1. 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.

  2. 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.

  3. 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.

  4. Magnesium and Space Flight

    Science.gov (United States)

    Smith, Scott M.; Zwart, Sara R.

    2016-01-01

    Magnesium is an essential nutrient for muscle, cardiovascular, and bone health on Earth, and during space flight. We sought to evaluate magnesium status in astronauts before, during, and after space missions, in 43 astronauts (34 male, 9 female) on 4-6 month space flight missions. We also studied individuals participating in a ground analog of space flight, (head-down tilt bed rest, n=27, 35 +/- 7 y). We evaluated serum concentration and 24-hour 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-d 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- to 6-month space missions.

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

    Science.gov (United States)

    Forrest, C. J.; 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.

    2016-11-01

    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 C15H11NO + 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 × 106. With these enhancements, the 13.4-m nTOF can measure the D(t,n)4He and D(d,n)3He 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 × 109 to 1 × 1014 and the ion temperature with an accuracy approaching 5% for both the D(t,n)4He and D(d,n)3He reactions.

  6. 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.

  7. Chlorine atom formation dynamics in the dissociation of halogenated pyridines after photoexcitation at 235 nm: A resonance enhanced multiphoton ionization-time of flight (REMPI-TOF) study

    Science.gov (United States)

    Srinivas, D.; Upadhyaya, Hari P.

    2016-06-01

    The photodissociation dynamics of halogen substituted pyridines, namely, 3-chloropyridine (ClPy) and 3-chloro-2,4,5,6-tetrafluoropyridine (ClFPy), has been studied around 235 nm by detecting chlorine atoms in their spin orbit states Cl(2P3/2) and Cl∗(2P1/2) using the REMPI-TOF technique. We have determined the translational energy distribution, the recoil anisotropy parameter, β, and the spin-orbit branching ratio, for chlorine atom elimination channels. The TOF profiles for Cl and Cl∗ are found to be independent of laser polarization suggesting a zero value for β, within the experimental uncertainties. For 3-chloropyridine, the average translational energies for Cl and Cl∗ elimination channels are determined to be 3.7 ± 1.0 and 7.0 ± 1.5 kcal/mol, respectively. Similarly, for 3-chloro-2,4,5,6-tetrafluoropyridine, the average translational energies for Cl and Cl∗ elimination channels are determined to be 8.0 ± 1.5 and 9.0 ± 1.5 kcal/mol, respectively. The theoretical calculation suggests that the fluorine substitution increases the possibility of cross over to the π-σ∗ state from the initially prepared π-π∗ state.

  8. A Dynamic Optimization Research of Flight Seat Inventory Control Based on the Hub and Spoke Route Network%基于轮辐式航线网络的航班舱位控制动态优化

    Institute of Scientific and Technical Information of China (English)

    高金敏; 乐美龙

    2015-01-01

    To keep the seat inventory control closer to actual passenger reservation demand , and effectively improve airline revenue , a dynamic optimization model of seat inventory control is established based on the characteristics of the hub and spoke route network , from the perspective of practical operation , considering demand uncertainty and dynamics at the same time .The random arrival passenger number of different res-ervation phases is obtained by simulation , the number of seats to protect each flight segment is obtained by using genetic algorithm , and the nested grade is obtained according to the fare value .The running results show that this method can increase the total revenue by 2 .35%compared with the method using genetic al-gorithm only .It has certain reference significance .%为使航班舱位控制更贴近旅客实际订座需求,有效提高航空公司收益,基于轮辐式航线网络结构的特点,从航班实际运行的角度出发,同时考虑需求的不确定性以及动态性,建立舱位控制动态优化模型。通过模拟仿真得到各订座阶段旅客随机到达数量,运用遗传算法求得各航班舱位等级的座位保护数,根据票价价值进行等级嵌套。结果表明,该方法与单独使用遗传算法的舱位控制方法相比较,能将总收益提高2.35%,具有一定的参考意义。

  9. UAV Flight Control System Based on an Intelligent BEL Algorithm

    Directory of Open Access Journals (Sweden)

    Huangzhong Pu

    2013-02-01

    Full Text Available A novel intelligent control strategy based on a brain emotional learning (BEL algorithm is investigated in the application of the attitude control of a small unmanned aerial vehicle (UAV in this study. The BEL model imitates the emotional learning process in the amygdala‐ orbitofrontal (A‐O system of mammalian brains. Here it is used to develop the flight control system of the UAV. The control laws of elevator, aileron and rudder manipulators adopt the forms of traditional flight control laws, and three BEL models are used in above three control loops, to on‐ line regulate the control gains of each controller. Obviously, a BEL intelligent control system is self‐learning and self‐adaptive, which is important for UAVs when flight conditions change, while traditional flight control systems remain unchanged after design. In simulation, the UAV is on a flat flight and suddenly a wind disturbs it making it depart from the equilibrium state. In order to make the UAV recover to the original equilibrium state, the BEL intelligent control system is adopted. The simulation results illustrate that the BEL‐based intelligent flight control system has characteristics of better adaptability and stronger robustness, when compared with the traditional flight control system.

  10. 基于MEMS惯性传感器的微型姿态测量系统%Micro Attitude Determination System Based on MEMS Inertial Sensors

    Institute of Scientific and Technical Information of China (English)

    翟昱涛; 魏强; 王晓浩; 周兆英

    2009-01-01

    提出了一种基于低成本MEMS惯性传感器的微型姿态测量系统,包括MEMS速率陀螺、MEMS磁强计、单轴MEMS加速度传感器.重点研究了基于扩展Kalman滤波(EKF)的姿态估计创新算法,通过速率陀螺更新误差状态四元数计算姿态角,并通过飞行方向的加速度传感器和三轴磁强计来补偿陀螺漂移和姿态角误差.利用扩展卡尔曼滤波方程消除瞬时干扰,实现高动态姿态测量.系统的仿真和高动态实验表明,姿态测量动态精度低于5°,静态精度低于0.7°.%In this paper, a micro attitude determination system with a novel attitude estimating algorithm used among the aerial Held is proposed based on low cost MEMS inertial sensors, including MEMS rate gyros, MEMS accelerometer and MEMS magnetometers. This paper presents the attitude estimating algorithm based on the error quaternion formulation, whereby the error quaternion is selected to compose the state vector that is updated by output of MEMS rate gyros. In order to estimate the attitude during high dynamic maneuvers, the earth's magnetic field and the effective part of gravity along the motion direction as the two measured quantities are introduced as virtual measurements in the extended Kalman filter ( EKF) which decreases short-term errors. Simulation and flight experimental results indicate that attitude quaternion is determined with standard deviations below 5°even in high dynamics and 0. 7°in static state.

  11. DRUG USE ATTITUDE OF TURKISH ARMED FORCES PILOTS

    Directory of Open Access Journals (Sweden)

    Ahmet SEN

    Full Text Available Introduction: Because of the dangers in the nature of flight, pilots have to fly in perfect medical conditions. Besides the undesirable effects of the diseases, side effects of the medications used in the treatment might also risk flight safety. In this study, we investigated the drug use attitude of Turkish Armed Forces pilots. Material-Method: In order to investigate their drug use attitude, a questionnaire was given to 408 pilots at GATA Aerospace Medical Center. Drug use attitude, drugs used by pilots and side effects were questioned. Results: 41 % of pilots reported that they used drugs during active flying. But the drug use rate of Army pilots was 57 %, which was higher than the Air Force and Navy pilots. The most common used drugs were analgesics. Conclusion: It is obvious that pilots might use drugs without informing their flight surgeon. Flight surgeons should always educate the pilots about the importance and dangers of self-medication. [TAF Prev Med Bull 2004; 3(9.000: 213-220

  12. 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…

  13. Asymmetrical international attitudes

    NARCIS (Netherlands)

    Van Oudenhoven, JP; Askevis-Leherpeux, F; Hannover, B; Jaarsma, R; Dardenne, B

    2002-01-01

    In general, attitudes towards nations have a fair amount of reciprocity: nations either like each other are relatively indifferent to each other or dislike each other Sometimes, however international attitudes are asymmetrical. In this study, we use social identity theory in order to explain asymmet

  14. Adolescent Attitudes about Rape.

    Science.gov (United States)

    Kershner, Ruth

    1996-01-01

    A very significant problem in society is adolescent rape victimization and the growing number of adolescent perpetrators. This paper examines adolescent attitudes about rape in order to develop curricular materials. It is found that adolescents exhibit conservative attitudes about gender roles, general rape myths, and victim issues. (Author)

  15. Hierarchical Models of Attitude.

    Science.gov (United States)

    Reddy, Srinivas K.; LaBarbera, Priscilla A.

    1985-01-01

    The application and use of hierarchical models is illustrated, using the example of the structure of attitudes toward a new product and a print advertisement. Subjects were college students who responded to seven-point bipolar scales. Hierarchical models were better than nonhierarchical models in conceptualizing attitude but not intention. (GDC)

  16. 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)

  17. Measuring Attitude Functions.

    Science.gov (United States)

    Anderson, Deborah S.; Kristiansen, Connie M.

    1990-01-01

    Discusses the Attitude Functions Inventory (AFI), which assesses the extent to which a person's attitude fulfills each of four psychological functions. Reports findings of a study, involving 249 undergraduates, that tested the construct validity of the AFI. Suggests that the AFI provides conceptually meaningful measures of the functions of…

  18. 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....

  19. Flight Planning Branch Space Shuttle Lessons Learned

    Science.gov (United States)

    Price, Jennifer B.; Scott, Tracy A.; Hyde, Crystal M.

    2011-01-01

    Planning products and procedures that allow the mission flight control teams and the astronaut crews to plan, train and fly every Space Shuttle mission have been developed by the Flight Planning Branch at the NASA Johnson Space Center. As the Space Shuttle Program ends, lessons learned have been collected from each phase of the successful execution of these Shuttle missions. Specific examples of how roles and responsibilities of console positions that develop the crew and vehicle attitude timelines will be discussed, as well as techniques and methods used to solve complex spacecraft and instrument orientation problems. Additionally, the relationships and procedural hurdles experienced through international collaboration have molded operations. These facets will be explored and related to current and future operations with the International Space Station and future vehicles. Along with these important aspects, the evolution of technology and continual improvement of data transfer tools between the shuttle and ground team has also defined specific lessons used in the improving the control teams effectiveness. Methodologies to communicate and transmit messages, images, and files from Mission Control to the Orbiter evolved over several years. These lessons have been vital in shaping the effectiveness of safe and successful mission planning that have been applied to current mission planning work in addition to being incorporated into future space flight planning. The critical lessons from all aspects of previous plan, train, and fly phases of shuttle flight missions are not only documented in this paper, but are also discussed as how they pertain to changes in process and consideration for future space flight planning.

  20. Peculiarities of transformation of adaptation level of the astronaut in conditions of long-lasting flight

    Science.gov (United States)

    Padashulya, H.; Prisnyakova, L.; Prisnyakov, V.

    Prognostication of the development of adverse factors of psychological processes in the personality of the astronaut who time and again feels transformation of internal structure of his personality is one of cardinal problems of the long-lasting flight Adaptation to changing conditions of long-lasting flight is of particular importance because it has an effect on the efficiency of discharged functions and mutual relations in the team The fact of standard psychological changes emerging in the personality being in the state of structural transformations is the precondition for the possibility of prognostication Age-specific gender and temperamental differences in the personality enable to standardize these changes Examination of the process of transformation of adaptation level of the personality in the varied environment depending on the type of temperament and constituents age and gender is chief object of the report In the report it is shown that in the process of transformation of adaptation parameters - attitude to guillemotleft work guillemotright guillemotleft family guillemotright guillemotleft environment guillemotright and guillemotleft ego guillemotright - the changes can go in two directions - in the direction of increase and decline of indexes The trend of increase enables to accumulate them and form potentiality to reduce or increase the level of personality adaptation There is a hypothesis that the dynamics of the process of transformation of adaptation parameter is shown up in the orientation of increase of

  1. Video-Based Sensor for Robotic Position and Attitude determination

    Science.gov (United States)

    Howard, Richard T.; Bryan, Thomas C.; Book, Michael L.; Roe, Fred D., Jr. (Technical Monitor)

    2001-01-01

    NASA's Marshall Space Flight Center (MSFC) has, for the last ten years, developed various video-based sensors for use in automated docking systems. The latest generation of sensor will operate at rates of up to 100 Hz, determining the relative position (X, Y, and Z) and attitude (Roll, Pitch, and Yaw) between the sensor and a small 3-dimensional target, making it suitable for applications in robotic sensing. The Advanced Video Guidance Sensor (AVGS) is designed to track multiple targets at different ranges and determine the position and attitude of each one. The previous generation of video sensor, the Video Guidance Sensor (VGS), was flown twice on the Space Shuttle to test its performance on orbit. One of the tests performed was determining the relative positions and attitudes between the VGS and its target, which was moved to various positions using the Remote Manipulator System (RMS). The RMS position data and VGS measured data were analyzed after the flights, with good correlation between the position and attitude data of the two data sets. The test using the RMS gives a good idea of the ability of the use of the AVGS as a sensor for end-effector position and attitude determination.

  2. Acquisition of a Biomedical Database of Acute Responses to Space Flight during Commercial Personal Suborbital Flights

    Science.gov (United States)

    Charles, John B.; Richard, Elizabeth E.

    2010-01-01

    There is currently too little reproducible data for a scientifically valid understanding of the initial responses of a diverse human population to weightlessness and other space flight factors. Astronauts on orbital space flights to date have been extremely healthy and fit, unlike the general human population. Data collection opportunities during the earliest phases of space flights to date, when the most dynamic responses may occur in response to abrupt transitions in acceleration loads, have been limited by operational restrictions on our ability to encumber the astronauts with even minimal monitoring instrumentation. The era of commercial personal suborbital space flights promises the availability of a large (perhaps hundreds per year), diverse population of potential participants with a vested interest in their own responses to space flight factors, and a number of flight providers interested in documenting and demonstrating the attractiveness and safety of the experience they are offering. Voluntary participation by even a fraction of the flying population in a uniform set of unobtrusive biomedical data collections would provide a database enabling statistical analyses of a variety of acute responses to a standardized space flight environment. This will benefit both the space life sciences discipline and the general state of human knowledge.

  3. Flight Systems Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project will develop the Flight System Monitor which will use non-intrusive electrical monitoring (NEMO). The electronic system health of...

  4. Design and validation of inverse optimisation software for the attitude control of microsatellites

    Science.gov (United States)

    Horri, N. M.; Palmer, P.; Roberts, M.

    2011-12-01

    The capabilities of microsatellite attitude control hardware have considerably evolved during the last two decades. However, three axis attitude control software is still predominantly based on the conservative use of standard flight proven PD type controllers, which are known to be limited in terms of rapidity for a prescribed level of energy consumption. Microsatellites are therefore typically not as agile as they could be. This conservatism is due to the complexity of implementing global numerical optimisation techniques to satellite attitude control. In this paper, we consider the model of a low earth orbiting microsatellite with a four wheel configuration, where the speed of one of the wheels is kept constant to provide a momentum bias and guarantee gyroscopic stiffness to disturbances. A geometric optimal control approach is presented, which circumvents the tedious tasks of numerically solving online the nonlinear optimisation problem. The approach is based on the design of suboptimal phase space trajectories. The phase space trajectory of a standard linear controller, typically a PD law with gyro-compensation, is used as a benchmark. The proposed inverse optimal control technique is then used to enforce higher convergence rate constraints than the benchmark law, without increasing the total energy consumption. The convergence rate of a Lyapunov function under the effect of the optimal controller outperforms the convergence rate of the same function under PD control and keeps increasing until a design settling time limit is reached. Guidelines are given for the tuning of the controller. The optimal attitude control algorithms are validated on a microsatellite software simulator in collaboration with the space company Surrey Satellite Technology Limited (SSTL). The software simulator incorporates a precise model of the effects of estimation errors, noise, external disturbances, sampling and actuator dynamics. The software is similar to the flight software of

  5. INSECT FLIGHT - BIOACOUSTICAL APPROACH

    OpenAIRE

    Gopala Krishna, G.; Krishna Shankar, B.; Ahmad, A.

    1990-01-01

    Insect aerodynamics is drawing the attention of a number of researchers belonging to different disciplines with a view to understand its aerodynamic capabilities so as to revolutionise the aircraft technology. It is possible to understand, to some extent, the insect aerodynamics by experimentally determining the frequency of wing beat in its fethered state of flight by using flight sound technique and computing rate of mass flow, velocity, acceleration and mass of air induced in downward dire...

  6. Flight Crew Scheduling

    OpenAIRE

    Graves, Glenn W.; Richard D. McBride; Ira Gershkoff; Diane Anderson; Deepa Mahidhara

    1993-01-01

    A new crew scheduling optimization system has been developed for United Airlines. The system was developed to permit quick response to schedule changes and to reduce crew scheduling costs. It was designed to work efficiently for both the medium sized problems (300 flights daily) and the very large problems (1,700 flights daily) that United must solve. The system has two main components, a generator and an optimizer. The generator creates pairings (candidate crew trips) which are fed as variab...

  7. 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.

  8. Magnesium and Space Flight.

    Science.gov (United States)

    Smith, Scott M; Zwart, Sara R

    2015-12-08

    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.

  9. Interprofessional Flight Camp.

    Science.gov (United States)

    Alfes, Celeste M; Rowe, Amanda S

    2016-01-01

    The Dorothy Ebersbach Academic Center for Flight Nursing in Cleveland, OH, holds an annual flight camp designed for master's degree nursing students in the acute care nurse practitioner program, subspecializing in flight nursing at the Frances Payne Bolton School of Nursing at Case Western Reserve University. The weeklong interprofessional training is also open to any health care provider working in an acute care setting and focuses on critical care updates, trauma, and emergency care within the critical care transport environment. This year, 29 graduate nursing students enrolled in a master's degree program from Puerto Rico attended. Although the emergency department in Puerto Rico sees and cares for trauma patients, there is no formal trauma training program. Furthermore, the country only has 1 rotor wing air medical transport service located at the Puerto Rico Medical Center in San Juan. Flight faculty and graduate teaching assistants spent approximately 9 months planning for their participation in our 13th annual flight camp. Students from Puerto Rico were extremely pleased with the learning experiences at camp and expressed particular interest in having more training time within the helicopter flight simulator.

  10. 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.

  11. A Few Questions on Flight Control System Research and Design of Near Space Vehicle%关于近空间飞行器飞行控制系统研究设计的几个问题

    Institute of Scientific and Technical Information of China (English)

    姜长生

    2015-01-01

    Several problems on the flight control system design of Near Space Vehicle ( NSV ) are discussed. Firstly, the recent developments and the importance of NSV research are introduced. Then, several important problems for the NSV flight control are discussed, including:1 ) modeling of NSV flight motion control;2 ) robustness of NSV flight attitude control;3 ) integrated coordination control between flight attitude and centre-of-gravity motion;4 ) integrated coordination control between flight and engine control;and 5 ) anti-disturbance of flight control. The corresponding view is given and methods are proposed for solution of the problems. At last, the author’s viewpoints on design principles of NSV flight control system are presented, and the significance of applying integrated coordination control idea in NSV flight control system design is pointed out.

  12. 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

  13. GENIE Flight Test Results and System Overview

    Science.gov (United States)

    Brady, Tye; Paschall, Stephen, II; Crain, Timothy P., II; Demars, Kyle; Bishop, Robert

    2011-01-01

    NASA has envisioned a suite of lander test vehicles that will be flown in Earth s atmosphere to incrementally demonstrate applicable lunar lander performance in the terrestrial environment. As each terrestrial rocket progresses in maturity, relevant space flight technology matures to a higher technology readiness level, preparing it for inclusion on a future lunar lander design.. NASA s "Project M" lunar mission concept flew its first terrestrial rocket, RR1, in June 2010 in Caddo Mills, Texas. The Draper Laboratory built GENIE (Guidance Embedded Navigator Integration Environment) successfully demonstrated accurate, real time, embedded performance of Project M navigation and guidance algorithms in a highly dynamic environment. The RR1 vehicle, built by Armadillo Aerospace, performed a successful 60 second free flight and gave the team great confidence in Project M s highly reliable and robust GNC system design and implementation. This paper provides an overview of the GENIE system and describes recent flight performance test results onboard the RR1 terrestrial rocket.

  14. 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.

  15. DOA estimation for attitude determination on communication satellites

    Institute of Scientific and Technical Information of China (English)

    Yang Bin; He Feng; Jin Jin; Xiong Huagang; Xu Guanghan

    2014-01-01

    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.

  16. Flight evaluation of a computer aided low-altitude helicopter flight guidance system

    Science.gov (United States)

    Swenson, Harry N.; Jones, Raymond D.; Clark, Raymond

    1993-01-01

    The Flight Systems Development branch of the U.S. Army's Avionics Research and Development Activity (AVRADA) and NASA Ames Research Center have developed for flight testing a Computer Aided Low-Altitude Helicopter Flight (CALAHF) guidance system. The system includes a trajectory-generation algorithm which uses dynamic programming and a helmet-mounted display (HMD) presentation of a pathway-in-the-sky, a phantom aircraft, and flight-path vector/predictor guidance symbology. The trajectory-generation algorithm uses knowledge of the global mission requirements, a digital terrain map, aircraft performance capabilities, and precision navigation information to determine a trajectory between mission way points that seeks valleys to minimize threat exposure. This system was developed and evaluated through extensive use of piloted simulation and has demonstrated a 'pilot centered' concept of automated and integrated navigation and terrain mission planning flight guidance. This system has shown a significant improvement in pilot situational awareness, and mission effectiveness as well as a decrease in training and proficiency time required for a near terrain, nighttime, adverse weather system. AVRADA's NUH-60A STAR (Systems Testbed for Avionics Research) helicopter was specially modified, in house, for the flight evaluation of the CALAHF system. The near terrain trajectory generation algorithm runs on a multiprocessor flight computer. Global Positioning System (GPS) data are integrated with Inertial Navigation Unit (INU) data in the flight computer to provide a precise navigation solution. The near-terrain trajectory and the aircraft state information are passed to a Silicon Graphics computer to provide the graphical 'pilot centered' guidance, presented on a Honeywell Integrated Helmet And Display Sighting System (IHADSS). The system design, piloted simulation, and initial flight test results are presented.

  17. 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.

  18. 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...

  19. 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...

  20. X-2 in flight

    Science.gov (United States)

    1956-01-01

    This inflight photograph of the X-2 (46-674) shows the twin set of shock-diamonds, characteristic of supersonic conditions in the exhaust plume from the two-chamber rocket engine. The Curtiss-Wright XLR-25 rocket engine caused one of several problems that delayed flight of the X-2. At one point, people in the project suggested its replacement. It was the first 'man-rated' (in the terminology of the day) rocket engine that was throttleable, and the technology was not yet mature. Other problems included the X-2's landing gear and the replacement of the planned electronic flight controls with a conventional hydromechanical system like that used in the F-86. The X-2 was a swept-wing, rocket-powered aircraft designed to fly faster than Mach 3 (three times the speed of sound). It was built for the U.S. Air Force by the Bell Aircraft Company, Buffalo, New York. The X-2 was flown to investigate the problems of aerodynamic heating as well as stability and control effectiveness at high altitudes and high speeds (in excess of Mach 3). Bell aircraft built two X-2 aircraft. These were constructed of K-monel (a copper and nickel alloy) for the fuselage and stainless steel for the swept wings and control surfaces. The aircraft had ejectable nose capsules instead of ejection seats because the development of ejection seats had not reached maturity at the time the X-2 was conceived. The X-2 ejection canopy was successfully tested using a German V-2 rocket. The X-2 used a skid-type landing gear to make room for more fuel. The airplane was air launched from a modified Boeing B-50 Superfortress Bomber. X-2 Number 1 made its first unpowered glide flight on Aug. 5, 1954, and made a total of 17 (4 glide and 13 powered) flights before it was lost Sept. 27, 1956. The pilot on Flight 17, Capt. Milburn Apt, had flown the aircraft to a record speed of Mach 3.2 (2,094 mph), thus becoming the first person to exceed Mach 3. During that last flight, inertial coupling occurred and the pilot was

  1. 14 CFR 121.493 - Flight time limitations: Flight engineers and flight navigators.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Flight time limitations: Flight engineers and flight navigators. 121.493 Section 121.493 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Flight...

  2. Lessons from dragonfly flight

    Science.gov (United States)

    Wang, Z. Jane

    2005-11-01

    I will describe two lessons we learned from analyzing dragonfly flight using computers and table-top experiments. Part I: The role of drag in insect flight. Airplanes and helicopters are airborne via aerodynamic lift, not drag. However, it is not a priori clear that insects use only lift to fly. We find that dragonfly uses mainly drag to hover, which explains an anomalous factor of four in previous estimates of dragonfly lift coefficients, where drag was assumed to be negligible. Moreover, we show that the use of drag for flight is efficient at insect size. This suggests a re-consideration of the hovering efficiency of flapping flight, which is no longer described by the lift to drag ratio. Part II. Fore-hind wing interaction in dragonfly flight. A distinctive feature of dragonflies is their use of two pairs of wings which are driven by separate direct muscles. Dragonflies can actively modulate the phase delay between fore-hind wings during different maneuver. We compute the Navier-Stokes equation around two wings following the motion measured from our tethered dragonfly experiments, and find an explanation of the advantage of counter-stroking during hovering.

  3. Attitudes to audit

    OpenAIRE

    Waters, W. H. R.; Kelly, J.; Lunn, J E

    1983-01-01

    An exercise in audit was arranged jointly by the Local Medical Committee and the Royal College of General Practitioners in the Doncaster area. This was followed up by a questionnaire enquiring about attitudes to the audit.

  4. 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....

  5. 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...

  6. Attitudes Toward Single Parenthood

    OpenAIRE

    Pećnik, Ninoslava; Raboteg-Šarić, Zora

    2010-01-01

    Changes in the family structure produce different social reactions, and the negative attitude of society towards single parent families can generate social vulnerability of this group. (The lack of) understanding of the environment influences not only the behaviour of other persons toward single parents and their children, but also their attitudes and personal experience of single parenthood. In order to improve the insight into the experience of new forms of family in our society, a survey o...

  7. 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.

  8. 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.

  9. Attitudes and Beliefs in Advertising

    OpenAIRE

    Pohořelá, Denisa

    2011-01-01

    Bachelor thesis of name „Attitudes and Belief in Advertising“ considers determination of general attitude towards advertising and testing of factors which effect advertising message´s consignee. Belief in advertising has character of general attitude or attitude towards brand. My bachelor abstract recognizes particulary these general attitudes. Working factors in advertising are: relation, politics, sex, symbolism, family. For this purpose questionnaire research was chosen. A part ...

  10. 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.

  11. Flight Dynamics Modeling and Analysis of High Aspect Ratio UAV Based on Flexible Beam Model%基于柔性梁模型的大展弦比无人机动力学建模与分析

    Institute of Scientific and Technical Information of China (English)

    李满; 宋笔锋; 焦景山; 胡铁玉

    2013-01-01

    高空长航时大展弦比无人机机翼结构刚度小,在飞行中变形幅度大且特征频率低,与无人机飞行动力学响应耦合,改变了无人机的飞行动力学特性。为研究其影响,对大展弦比机翼结构进行空间梁假设,利用Hodges本征梁动力学模型,结合大展弦比气动力片条理论和准定常假设对无人机进行建模,计算配平状态下无人机的静变形。机翼柔性改变了无人机的纵向静稳定性,在不同推力分布下,计算并比较柔性无人机纵向静稳定性变化。计算不同飞行高度、结构刚度和有效载荷挂载情形下的无人机的纵向飞行品质,结果显示由于静弹性变形改变无人机配平状态下的俯仰转动惯量,导致无人机的纵向短周期频率减小,阻尼增大。由于机翼柔性的影响,无人机纵向长周期运动与结构弯曲变形运动发生耦合。%The high aspect ratio wing of the High Altitude Long Endurance ( HALE) UAV is flexible, causing the UAV to have large structural deformation .Adopting the spatial beam assumption of the high aspect ratio wing , this paper studies the flight dynamics of the UAV uses Hodges intrinsic beam dynamics model combined with aerody -namic strip theory and quasi-steady assumption , uses this method , computes the static deformation in trim state , analyzes the stability in different thrust distribution , calculates the flying qualities in different altitudes , structural rigidities and payload distributions .The results and their analysis show preliminarily that:( 1) the flexible high as-pect ratio wing changes the longitudinal static stability and the pitch inertia of the UAV , resulting in decreased short cycle frequency and increased damping;( 2) the phugoid motion couples with structure bending motion .

  12. 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.

  13. 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

  14. Flight calls and orientation

    DEFF Research Database (Denmark)

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

    2008-01-01

      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...... 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...... 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....

  15. Radio astronomy Explorer-B postlaunch attitude operations analysis

    Science.gov (United States)

    Werking, R. D.; Berg, R.; Brokke, K.; Hattox, T.; Lerner, G.; Stewart, D.; Williams, R.

    1974-01-01

    The attitude support activities of the Radio Astronomy Explorer-B are reported. The performance of the spacecraft hardware and software are discussed along with details of the mission events, from launch through main boom deployment. Reproductions of displays are presented which were used during support activities. The interactive graphics proved the support function by providing the quality control necessary to ensure mission success in an environment where flight simulated ground testing of spacecraft hardware cannot be performed.

  16. Technologies for hypersonic flight

    Science.gov (United States)

    Steinheil, Eckart; Uhse, Wolfgang

    An account is given of the technology readiness requirements of the West German Saenger II air-breathing first-stage, two-stage reusable launcher system. The present, five-year conceptual development phase will give attention to propulsion, aerothermodynamic, materials/structures, and flight guidance technology development requirements. The second, seven-year development phase will involve other West European design establishments and lead to the construction of a demonstration vehicle. Attention is presently given to the air-breathing propulsion system, and to flight-weight structural systems under consideration for both external heating and internal cryogenic tankage requirements.

  17. MODEL OF CENTRIFUGAL EFFECT AND ATTITUDE MANEUVER STABILITY OF A COUPLED RIGID-FLEXIBLE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-bin; WANG Zhao-lin; WANG Tian-shu; LIU Ning

    2005-01-01

    The influences of nonlinear centrifugal force to large overall attitude motion of coupled rigid-flexible system was investigated. First the nonlinear model of the coupled rigidflexible system was deduced from the idea of "cenlrifugal potential field", and then the dynamic effects of the nonlinear centrifugal force to system attitude motion were analyzed by approximate calculation; At last, the Lyapunov function based on energy norm was selected,in the condition that only the measured values of attitude and attitude speed are available,and it is proved that the PD feedback control law can ensure the attitude stability during large angle maneuver.

  18. A new flocking model through body attitude coordination

    OpenAIRE

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

    2016-01-01

    We present a new model for multi-agent dynamics where each agent is described by its position and body attitude: agents travel at a constant speed in a given direction and their body can rotate around it adopting different configurations. In this manner, the body attitude is described by three orthonormal axes giving an element in $SO(3)$ (rotation matrix). Agents try to coordinate their body attitudes with the ones of their neighbours. In the present paper, we give the Individual Based Model...

  19. Measuring Attitudes Toward Inclusion

    Directory of Open Access Journals (Sweden)

    André Kunz

    2010-12-01

    Full Text Available The considerable worldwide demand for an inclusive education system has driven Switzerland to reconsider the approach of segregated schooling for children with Special Educational Needs (SEN. Recently, an agreement was signed among the states with the intention to adopt a more inclusive practice in school. There is evidence suggesting that an inclusive practice established at policy level is not enough, as many times it becomes teacher’s effort to translate the policies in classroom setting. The effectiveness of inclusive practices can be tightly related to the attitude of teachers, parents and students to inclusion of children with SEN in mainstreaming classes. Attitude towards inclusion is an observable construct but it presents difficulties in terms of measurement. For this purpose, in order to evaluate the attitude to inclusion of teachers, parents and students, an American Scale, the 11-items Parent Attitude to Inclusion (Palmer et al., 1998a, 1998b, 2001 and the version for teachers (Stanley, Grimbeek, Bryer, Beamisch, 2003; Bryer, Grimbeek, Beamish, Stanley, 2004, has been slightly modified and translated into German language. The resulting scales have been used to collect data in Switzerland in two regions. Results show that the German version of the scale can be potentially used for reliable measurement of attitudes toward inclusion in German speaking countries.

  20. Evolution of avian flight: muscles and constraints on performance.

    Science.gov (United States)

    Tobalske, Bret W

    2016-09-26

    Competing hypotheses about evolutionary origins of flight are the 'fundamental wing-stroke' and 'directed aerial descent' hypotheses. Support for the fundamental wing-stroke hypothesis is that extant birds use flapping of their wings to climb even before they are able to fly; there are no reported examples of incrementally increasing use of wing movements in gliding transitioning to flapping. An open question is whether locomotor styles must evolve initially for efficiency or if they might instead arrive due to efficacy. The proximal muscles of the avian wing output work and power for flight, and new research is exploring functions of the distal muscles in relation to dynamic changes in wing shape. It will be useful to test the relative contributions of the muscles of the forearm compared with inertial and aerodynamic loading of the wing upon dynamic morphing. Body size has dramatic effects upon flight performance. New research has revealed that mass-specific muscle power declines with increasing body mass among species. This explains the constraints associated with being large. Hummingbirds are the only species that can sustain hovering. Their ability to generate force, work and power appears to be limited by time for activation and deactivation within their wingbeats of high frequency. Most small birds use flap-bounding flight, and this flight style may offer an energetic advantage over continuous flapping during fast flight or during flight into a headwind. The use of flap-bounding during slow flight remains enigmatic. Flap-bounding birds do not appear to be constrained to use their primary flight muscles in a fixed manner. To improve understanding of the functional significance of flap-bounding, the energetic costs and the relative use of alternative styles by a given species in nature merit study.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

  1. Evolution of avian flight: muscles and constraints on performance.

    Science.gov (United States)

    Tobalske, Bret W

    2016-09-26

    Competing hypotheses about evolutionary origins of flight are the 'fundamental wing-stroke' and 'directed aerial descent' hypotheses. Support for the fundamental wing-stroke hypothesis is that extant birds use flapping of their wings to climb even before they are able to fly; there are no reported examples of incrementally increasing use of wing movements in gliding transitioning to flapping. An open question is whether locomotor styles must evolve initially for efficiency or if they might instead arrive due to efficacy. The proximal muscles of the avian wing output work and power for flight, and new research is exploring functions of the distal muscles in relation to dynamic changes in wing shape. It will be useful to test the relative contributions of the muscles of the forearm compared with inertial and aerodynamic loading of the wing upon dynamic morphing. Body size has dramatic effects upon flight performance. New research has revealed that mass-specific muscle power declines with increasing body mass among species. This explains the constraints associated with being large. Hummingbirds are the only species that can sustain hovering. Their ability to generate force, work and power appears to be limited by time for activation and deactivation within their wingbeats of high frequency. Most small birds use flap-bounding flight, and this flight style may offer an energetic advantage over continuous flapping during fast flight or during flight into a headwind. The use of flap-bounding during slow flight remains enigmatic. Flap-bounding birds do not appear to be constrained to use their primary flight muscles in a fixed manner. To improve understanding of the functional significance of flap-bounding, the energetic costs and the relative use of alternative styles by a given species in nature merit study.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'. PMID:27528773

  2. Boeing flight deck design philosophy

    Science.gov (United States)

    Stoll, Harty

    1990-01-01

    Information relative to Boeing flight deck design philosophy is given in viewgraph form. Flight deck design rules, design considerations, functions allocated to the crew, redundancy and automation concerns, and examples of accident data that were reviewed are listed.

  3. Improvement of flight simulator feeling using adaptive fuzzy backlash compensation

    OpenAIRE

    Amara, Zied; Bordeneuve-Guibé, Joël

    2007-01-01

    In this paper we addressed the problem of improving the control of DC motors used for the specific application of a 3 degrees of freedom moving base flight simulator. Indeed the presence of backlash in DC motors gearboxes induces shocks and naturally limits the flight feeling. In this paper, dynamic inversion with Fuzzy Logic is used to design an adaptive backlash compensator. The classification property of fuzzy logic techniques makes them a natural candidate for the rejection of errors indu...

  4. Deterioration of Damselfly Flight Performance due to Wing Damage

    CERN Document Server

    Ren, Yan; Gai, Kuo; Li, Chengyu; Zeyghami, Samane; Dong, Haibo

    2011-01-01

    In this video, effect of chordwise damage on a damselfly (American Rubyspot)'s wings is investigated. High speed photogrammetry was used to collect the data of damselflies' flight with intact and damaged wings along the wing chord. Different level of deterioration of flight performance can be observed. Further investigation will be on the dynamic and aerodynamic roles of each wing with and without damage.

  5. 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. PMID:11148298

  6. The use of real-time, hardware-in-the-loop simulation in the design and development of the new Hughes HS601 spacecraft attitude control system

    Science.gov (United States)

    Slafer, Loren I.

    1989-01-01

    Realtime simulation and hardware-in-the-loop testing is being used extensively in all phases of the design, development, and testing of the attitude control system (ACS) for the new Hughes HS601 satellite bus. Realtime, hardware-in-the-loop simulation, integrated with traditional analysis and pure simulation activities is shown to provide a highly efficient and productive overall development program. Implementation of high fidelity simulations of the satellite dynamics and control system algorithms, capable of real-time execution (using applied Dynamics International's System 100), provides a tool which is capable of being integrated with the critical flight microprocessor to create a mixed simulation test (MST). The MST creates a highly accurate, detailed simulated on-orbit test environment, capable of open and closed loop ACS testing, in which the ACS design can be validated. The MST is shown to provide a valuable extension of traditional test methods. A description of the MST configuration is presented, including the spacecraft dynamics simulation model, sensor and actuator emulators, and the test support system. Overall system performance parameters are presented. MST applications are discussed; supporting ACS design, developing on-orbit system performance predictions, flight software development and qualification testing (augmenting the traditional software-based testing), mission planning, and a cost-effective subsystem-level acceptance test. The MST is shown to provide an ideal tool in which the ACS designer can fly the spacecraft on the ground.

  7. 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...... 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...... to explain unique variance in political orientation beyond the 'Big Six' broad dimensions as it relates to aspects not covered by the latter. Both hypotheses were tested in a web-based questionnaire study (N = 137). Besides replicating findings of previous research, results corroborated a strong positive...

  8. AIRSHIP ATTITUDE TRACKING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-liang; SHAN Xue-xiong

    2006-01-01

    The attitude tracking control problem for an airship with parameter uncertainties and external disturbances was considered in this paper. The mathematical model of the airship attitude is a multi-input/multi-output uncertain nonlinear system. Based on the characteristics of this system, a design method of robust output tracking controllers was adopted based on the upper-bounds of the uncertainties. Using the input/output feedback linearization approach and Liapunov method, a control law was designed, which guarantees that the system output exponentially tracks the given desired output. The controller is easy to compute and complement. Simulation results show that, in the closed-loop system, precise attitude control is accomplished in spite of the uncertainties and external disturbances in the system.

  9. 正丙醇和异丙醇的紫外光解动力学%Ultraviolet Photodissociation Dynamics of 1-Propanol and 2-Propanol by High-n Rydberg-Atom Time-of-flight(HRTOF) Technique

    Institute of Scientific and Technical Information of China (English)

    周卫东; 张劲松

    2002-01-01

    利用高里德堡态氢原子飞行时间(HRTOF)探测技术,研究了正丙醇和异丙醇的紫外光解动力学过程.在193.3 nm光辐射下,O-H键快速断裂过程构成主要的氢原子生成通道.伴随O-H键的碎裂,相当大的一部分能量转换成氢原子及其相应碎片的平动能(正丙醇〈fv〉=0.76; 异丙醇〈fv〉=0.78).氢原子碎片具有各向异性的角度分布;其角分布异向因子β分别为-0.79(正丙醇)和-0.77(异丙醇).研究结果表明,吸收1个193.3 nm光子后,丙醇分子跃迁到一个寿命很短的电子激发态;沿着O-H反应坐标,该激发态势能面是排斥的,因而O-H键快速断裂.此外,还得到了丙醇的O-H键离解能: (432±2)kJ/mol(正丙醇)和(433±2)kJ/mol(异丙醇).%193.3 nm photodissociation dynamics of jet-cooled 1-propanol and 2-propanol has been examined by using high-n Rydberg-atom time-of-flight (HRTOF) technique. Isotope labeling study indicates that O-H bond fission is the primary H-atom production channel. Center-of-mass (CM) product translational energy release of this channel is large, with 〈fT〉= 0.76 for H+1-propoxy and 0.78 for H+2-propoxy. Maximum CM translational energy release yields an upper limit of the O-H bond dissociation energy: (432±2)kJ/mol in 1-propanol and (433±2)kJ/mol in 2-propanol. H-atom product angular distribution is anisotropic (with β≈-0.79 for 1-propanol and -0.77 for 2-propanol), indicating a short excited-state lifetime. The 193.3 nm H-atom dissociation of both 1-propanol and 2-propanol is prompt and occurs on a repulsive excited-state potential energy surface.

  10. 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.

  11. 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; Sibonga, Jean; Keyak, Joyce; Nakamura, Toshitaka; Kohri, Kenjiro; Ohshima, Hiroshi; Moralez, Gilbert

    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+<2 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

  12. Attitudes towards documentary soundstracks

    DEFF Research Database (Denmark)

    Have, Iben

    2010-01-01

    Musical experience is often related to an emotional and imaginative engagement of the listener. Discourses of journalistic documentaries relate primarily to inferential knowledge systems in which the uses of background music as a communicative device become an object of epistemological critique....... 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......, the article will argue for the need for an acoustemological approach (Feld, 1996) to study the epistemological potential of sound in audiovisual media....

  13. 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......; only the first truth value is designated, i.e. yields the logical truths)....

  14. Attitude that Matters

    OpenAIRE

    Tiina Purhonen

    2007-01-01

    In this article, I compare the operativity of radical avant-garde and new dialogical art forms from one selected viewpoint. I discuss the issue of the artist's attitude as a significance-producing element in the artwork. For decades, artist-issued interpretation of art has been problematic. Thus it is interesting to question the significance of the strong definition of the artist's attitude, inherent in the theories of the new dialogical art. New dialogical art-forms are for example new genre...

  15. Spacecraft Attitude Determination

    DEFF Research Database (Denmark)

    Bak, Thomas

    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...

  16. Chaotic satellite attitude control by adaptive approach

    Science.gov (United States)

    Wei, Wei; Wang, Jing; Zuo, Min; Liu, Zaiwen; Du, Junping

    2014-06-01

    In this article, chaos control of satellite attitude motion is considered. Adaptive control based on dynamic compensation is utilised to suppress the chaotic behaviour. Control approaches with three control inputs and with only one control input are proposed. Since the adaptive control employed is based on dynamic compensation, faithful model of the system is of no necessity. Sinusoidal disturbance and parameter uncertainties are considered to evaluate the robustness of the closed-loop system. Both of the approaches are confirmed by theoretical and numerical results.

  17. Numerical study of insect free hovering flight

    Science.gov (United States)

    Wu, Di; Yeo, Khoon Seng; Lim, Tee Tai; Fluid lab, Mechanical Engineering, National University of Singapore Team

    2012-11-01

    In this paper we present the computational fluid dynamics study of three-dimensional flow field around a free hovering fruit fly integrated with unsteady FSI analysis and the adaptive flight control system for the first time. The FSI model being specified for fruitfly hovering is achieved by coupling a structural problem based on Newton's second law with a rigorous CFD solver concerning generalized finite difference method. In contrast to the previous hovering flight research, the wing motion employed here is not acquired from experimental data but governed by our proposed control systems. Two types of hovering control strategies i.e. stroke plane adjustment mode and paddling mode are explored, capable of generating the fixed body position and orientation characteristic of hovering flight. Hovering flight associated with multiple wing kinematics and body orientations are shown as well, indicating the means by which fruitfly actually maintains hovering may have considerable freedom and therefore might be influenced by many other factors beyond the physical and aerodynamic requirements. Additionally, both the near- and far-field flow and vortex structure agree well with the results from other researchers, demonstrating the reliability of our current model.

  18. Free-flight experiments in LISA Pathfinder

    CERN Document Server

    Armano, M; Auger, G; Baird, J; Binetruy, P; Born, M; Bortoluzzi, D; Brandt, N; Bursi, A; Caleno, M; Cavalleri, A; Cesarini, A; Cruise, M; Cutler, C; Danzmann, K; Diepholz, I; Dolesi, R; Dunbar, N; Ferraioli, L; Ferroni, V; Fitzsimons, E; Freschi, M; Gallegos, J; Marirrodriga, C Garcia; Gerndt, R; Gesa, LI; Gibert, F; Giardini, D; Giusteri, R; Grimani, C; Harrison, I; Heinzel, G; Hewitson, M; Hollington, D; Hueller, M; Huesler, J; Inchauspe, H; Jennrich, O; Jetzer, P; Johlander, B; Karnesis, N; Kaune, B; Korsakova, N; Killow, C; Lloro, I; Maarschalkerweerd, R; Madden, S; Maghami, P; Mance, D; Martin, V; Martin-Porqueras, F; Mateos, I; McNamara, P; Mendes, J; Mendes, L; Moroni, A; Nofrarias, M; Paczkowski, S; Perreur-Lloyd, M; Petiteau, A; Pivato, P; Plagnol, E; Prat, P; Ragnit, U; Ramos-Castro, J; Reiche, J; Perez, J A Romera; Robertson, D; Rozemeijer, H; Russano, G; Sarra, P; Schleicher, A; Slutsky, J; Sopuerta, C F; Sumner, T; Texier, D; Thorpe, J; Trenkel, C; Tu, H B; Vetrugno, D; Vitale, S; Wanner, G; Ward, H; Waschke, S; Wass, P; Wealthy, D; Wen, S; Weber, W; Wittchen, A; Zanoni, C; Ziegler, T; Zweifel, P

    2014-01-01

    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 underlyi...

  19. Star trackers for attitude determination

    OpenAIRE

    Liebe, Carl Christian

    1995-01-01

    One problem comes to all spacecrafts using vector information. That is the problem of determining the attitude. This paper describes how the area of attitude determination instruments has evolved from simple pointing devices into the latest technology, which determines the attitude by utilizing a CCD camera and a powerful microcomputer. The instruments are called star trackers and they are capable of determining the attitude with an accuracy better than 1 arcsecond. The concept of the star tr...

  20. Attitudes toward gambling among adolescents

    OpenAIRE

    Hanss, Daniel; Mentzoni, Rune Aune; Delfabbro, Paul; Myrseth, Helga; Pallesen, Ståle

    2014-01-01

    It is well documented that attitudes toward gambling are a good predictor of problem gambling during adolescence. However, so far, little is known about what factors are associated with adolescents' gambling attitudes. This study used cross-sectional data (N = 2055, response rate 70.4%) from a representative sample of 17-year-olds in Norway to investigate the relationship between demographic, personality, motivational and social variables and gambling attitudes. Overall, adolescents' attitude...

  1. 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.

  2. 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.

  3. Ordos Takes Flight

    Institute of Scientific and Technical Information of China (English)

    YAN WEI

    2010-01-01

    @@ China's vast hinterland has long conjured up images of rugged mountains and countrysides dotted by villages all but untouched by the hands of time. But after a recent one-hour flight west from Beijing,Anna Chennault,Chair of the Council for International Cooperation (CIC),a Washington,D.C.-based non-profit organization that helps promote development in China,found something altogether different-a city called Ordos.

  4. MARS Flight Engineering Status

    Energy Technology Data Exchange (ETDEWEB)

    Fast, James E.; Dorow, Kevin E.; Morris, Scott J.; Thompson, Robert C.; Willett, Jesse A.

    2010-04-06

    The Multi-sensor Airborne Radiation Survey Flight Engineering project (MARS FE) has designed a high purity germanium (HPGe) crystal array for conducting a wide range of field measurements. In addition to the HPGe detector system, a platform-specific shock and vibration isolation system and environmental housing have been designed to support demonstration activities in a maritime environment on an Unmanned Surface Vehicle (USV). This report describes the status of the equipment as of the end of FY09.

  5. 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.

  6. College Students' Attitudes toward Computers.

    Science.gov (United States)

    Leite, Pedro T.

    This paper reports a survey conducted at a private midwestern university to investigate 143 undergraduate students' attitudes toward computers. The study used a 10-item questionnaire called General Attitudes toward Computers. Results indicated that students had positive attitudes toward computers. There were no significant differences in attitudes…

  7. 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...

  8. Attitudes to nuclear waste

    International Nuclear Information System (INIS)

    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

  9. Attitudes toward Rape.

    Science.gov (United States)

    Larsen, Knud S.; Long, Ed

    While the perception of rape has been studied intensely in recent years, most scales focus on rape myths as the content domain. The need exists for a more general instrument which would include items from a variety of sources, e.g., attitudes toward rape awareness, sexual history, age, virginity, community support, etc., in addition to the myth of…

  10. Design and Simulation of an Adaptive Flight Control System for Unmanned Rotorcraft%无人旋翼飞行器自适应飞行控制系统设计与仿真

    Institute of Scientific and Technical Information of China (English)

    夏青元; 徐锦法; 张梁

    2013-01-01

    The principle of the model inverse controller is discussed in order to design an unmanned rotorcraft flight control system applicable to different mission tasks. A neural network compensation controller and online algorithms of its weight coefficients are proposed, and the stability of the synthesized controller is analyzed. The rotational dynamics inverse controller and translational dynamics inverse controller for the unmanned rotorcraft are deduced. The attitude inner loop controller and trajectory outer loop controller are designed. The control distribution strategy of the driving motor is determined to control the speed of coaxial rotor. A combined maneuver flight mission task is planned to imitate automatic flight motion. The adaptive flight control system is verified with simulation, and the flight control abilities of horizontal and vertical motion, hover and heading motion are demonstrated and validated. These results show that the designed adaptive flight control system has adaptability and robustness, and can realize attitude stability and trajectory following.%为了设计出能适应不同飞行任务的无人旋翼飞行器飞行控制系统,讨论了模型逆控制器原理.提出了神经网络补偿控制器及其权系数在线算法,分析了综合控制器稳定性.导出了无人旋翼飞行器旋转动力学逆控制器和平移动力学逆控制器,设计了姿态内回路控制器和轨迹外回路控制器,确定了共轴旋翼转速驱动电机的控制分配策略.规划了组合机动飞行科目来模拟自动飞行任务.通过仿真验证了自适应飞行控制系统对无人旋翼飞行器水平垂直运动、悬停和航向运动的飞行控制能力.结果表明,所设计的飞行控制系统具有自适应性和鲁棒性,能实现姿态与轨迹的稳定和跟踪控制.

  11. Study of tethered satellite active attitude control

    Science.gov (United States)

    Colombo, G.

    1982-01-01

    Existing software was adapted for the study of tethered subsatellite rotational dynamics, an analytic solution for a stable configuration of a tethered subsatellite was developed, the analytic and numerical integrator (computer) solutions for this "test case' was compared in a two mass tether model program (DUMBEL), the existing multiple mass tether model (SKYHOOK) was modified to include subsatellite rotational dynamics, the analytic "test case,' was verified, and the use of the SKYHOOK rotational dynamics capability with a computer run showing the effect of a single off axis thruster on the behavior of the subsatellite was demonstrated. Subroutines for specific attitude control systems are developed and applied to the study of the behavior of the tethered subsatellite under realistic on orbit conditions. The effect of all tether "inputs,' including pendular oscillations, air drag, and electrodynamic interactions, on the dynamic behavior of the tether are included.

  12. 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.

  13. 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...

  14. 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.

  15. Remote Attitude Measurement Sensor (RAMS)

    Science.gov (United States)

    Davis, H. W.

    1989-01-01

    Remote attitude measurement sensor (RAMS) offers a low-cost, low-risk, proven design concept that is based on mature, demonstrated space sensor technology. The electronic design concepts and interpolation algorithms were tested and proven in space hardware like th Retroreflector Field Tracker and various star trackers. The RAMS concept is versatile and has broad applicability to both ground testing and spacecraft needs. It is ideal for use as a precision laboratory sensor for structural dynamics testing. It requires very little set-up or preparation time and the output data is immediately usable without integration or extensive analysis efforts. For on-orbit use, RAMS rivals any other type of dynamic structural sensor (accelerometer, lidar, photogrammetric techniques, etc.) for overall performance, reliability, suitability, and cost. Widespread acceptance and extensive usage of RAMS will occur only after some interested agency, such as OAST, adopts the RAMS concept and provides the funding support necessary for further development and implementation of RAMS for a specific program.

  16. Gain-Scheduled Higher Harmonic Control for Full Flight Envelope Vibration Reduction

    OpenAIRE

    Fan, Frank H.; Hall, Steven

    2014-01-01

    This paper investigates the dynamics of the SMART rotor, and presents a method to design a gain-scheduled controller to reduce the harmonic vibration throughout the flight envelope. The dynamics of the SMART rotor was examined at various flight conditions through nonlinear simulation. The simulation results showed that the dynamics is strongly dependent on the advance ratio, but only weakly dependent on the blade loading and the rotor shaft angle. To reduce the higher harmonic vibration throu...

  17. Experience from the in-flight calibration of the Extreme Ultraviolet Explorer (EUVE) and Upper Atmosphere Research Satellite (UARS) fixed head star trackers (FHSTs)

    Science.gov (United States)

    Lee, Michael

    1995-01-01

    Since the original post-launch calibration of the FHSTs (Fixed Head Star Trackers) on EUVE (Extreme Ultraviolet Explorer) and UARS (Upper Atmosphere Research Satellite), the Flight Dynamics task has continued to analyze the FHST performance. The algorithm used for inflight alignment of spacecraft sensors is described and the equations for the errors in the relative alignment for the simple 2 star tracker case are shown. Simulated data and real data are used to compute the covariance of the relative alignment errors. Several methods for correcting the alignment are compared and results analyzed. The specific problems seen on orbit with UARS and EUVE are then discussed. UARS has experienced anomalous tracker performance on an FHST resulting in continuous variation in apparent tracker alignment. On EUVE, the FHST residuals from the attitude determination algorithm showed a dependence on the direction of roll during survey mode. This dependence is traced back to time tagging errors and the original post launch alignment is found to be in error due to the impact of the time tagging errors on the alignment algorithm. The methods used by the FDF (Flight Dynamics Facility) to correct for these problems is described.

  18. The Impact of Airline Flight Schedules on Flight Delays

    OpenAIRE

    Vinayak Deshpande; Mazhar Arıkan

    2012-01-01

    Airline flight delays have come under increased scrutiny lately in the popular press, with the Federal Aviation Administration data revealing that airline on-time performance was at its worst level in 13 years in 2007. Flight delays have been attributed to several causes such as weather conditions, airport congestion, airspace congestion, use of smaller aircraft by airlines, etc. In this paper, we examine the impact of the scheduled block time allocated for a flight, a factor controlled by ai...

  19. Flight Qualified Micro Sun Sensor

    Science.gov (United States)

    Liebe, Carl Christian; Mobasser, Sohrab; Wrigley, Chris; Schroeder, Jeffrey; Bae, Youngsam; Naegle, James; Katanyoutanant, Sunant; Jerebets, Sergei; Schatzel, Donald; Lee, Choonsup

    2007-01-01

    A prototype small, lightweight micro Sun sensor (MSS) has been flight qualified as part of the attitude-determination system of a spacecraft or for Mars surface operations. The MSS has previously been reported at a very early stage of development in NASA Tech Briefs, Vol. 28, No. 1 (January 2004). An MSS is essentially a miniature multiple-pinhole electronic camera combined with digital processing electronics that functions analogously to a sundial. A micromachined mask containing a number of microscopic pinholes is mounted in front of an active-pixel sensor (APS). Electronic circuits for controlling the operation of the APS, readout from the pixel photodetectors, and analog-to-digital conversion are all integrated onto the same chip along with the APS. The digital processing includes computation of the centroids of the pinhole Sun images on the APS. The spacecraft computer has the task of converting the Sun centroids into Sun angles utilizing a calibration polynomial. The micromachined mask comprises a 500-micron-thick silicon wafer, onto which is deposited a 57-nm-thick chromium adhesion- promotion layer followed by a 200-nm-thick gold light-absorption layer. The pinholes, 50 microns in diameter, are formed in the gold layer by photolithography. The chromium layer is thin enough to be penetrable by an amount of Sunlight adequate to form measurable pinhole images. A spacer frame between the mask and the APS maintains a gap of .1 mm between the pinhole plane and the photodetector plane of the APS. To minimize data volume, mass, and power consumption, the digital processing of the APS readouts takes place in a single field-programmable gate array (FPGA). The particular FPGA is a radiation- tolerant unit that contains .32,000 gates. No external memory is used so the FPGA calculates the centroids in real time as pixels are read off the APS with minimal internal memory. To enable the MSS to fit into a small package, the APS, the FPGA, and other components are mounted

  20. 14 CFR 125.297 - Approval of flight simulators and flight training devices.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Approval of flight simulators and flight... Flight Crewmember Requirements § 125.297 Approval of flight simulators and flight training devices. (a) Flight simulators and flight training devices approved by the Administrator may be used in...

  1. 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.

  2. Spacecraft Dynamic Characteristics While Deploying Flexible Beams

    Institute of Scientific and Technical Information of China (English)

    程绪铎; 李俊峰; 樊勇; 王照林

    2002-01-01

    The attitude dynamic equations of a spacecraft while deploying two flexible beams and the beam equations were developed from momentum theory. The dynamic equations were solved numerically using the Runge-Kutta method to calculate the vibration amplitudes of the flexible beams and the attitude angular velocity. The results show that the vibration amplitudes increase as the beam length increases or as the initial attitude angular velocity increases. The results also show that the vibration amplitudes decrease as the deployment velocity increases.

  3. Biomechanics and biomimetics in insect-inspired flight systems.

    Science.gov (United States)

    Liu, Hao; Ravi, Sridhar; Kolomenskiy, Dmitry; Tanaka, Hiroto

    2016-09-26

    Insect- and bird-size drones-micro air vehicles (MAV) that can perform autonomous flight in natural and man-made environments are now an active and well-integrated research area. MAVs normally operate at a low speed in a Reynolds number regime of 10(4)-10(5) or lower, in which most flying animals of insects, birds and bats fly, and encounter unconventional challenges in generating sufficient aerodynamic forces to stay airborne and in controlling flight autonomy to achieve complex manoeuvres. Flying insects that power and control flight by flapping wings are capable of sophisticated aerodynamic force production and precise, agile manoeuvring, through an integrated system consisting of wings to generate aerodynamic force, muscles to move the wings and a control system to modulate power output from the muscles. In this article, we give a selective review on the state of the art of biomechanics in bioinspired flight systems in terms of flapping and flexible wing aerodynamics, flight dynamics and stability, passive and active mechanisms in stabilization and control, as well as flapping flight in unsteady environments. We further highlight recent advances in biomimetics of flapping-wing MAVs with a specific focus on insect-inspired wing design and fabrication, as well as sensing systems.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

  4. Biomechanics and biomimetics in insect-inspired flight systems.

    Science.gov (United States)

    Liu, Hao; Ravi, Sridhar; Kolomenskiy, Dmitry; Tanaka, Hiroto

    2016-09-26

    Insect- and bird-size drones-micro air vehicles (MAV) that can perform autonomous flight in natural and man-made environments are now an active and well-integrated research area. MAVs normally operate at a low speed in a Reynolds number regime of 10(4)-10(5) or lower, in which most flying animals of insects, birds and bats fly, and encounter unconventional challenges in generating sufficient aerodynamic forces to stay airborne and in controlling flight autonomy to achieve complex manoeuvres. Flying insects that power and control flight by flapping wings are capable of sophisticated aerodynamic force production and precise, agile manoeuvring, through an integrated system consisting of wings to generate aerodynamic force, muscles to move the wings and a control system to modulate power output from the muscles. In this article, we give a selective review on the state of the art of biomechanics in bioinspired flight systems in terms of flapping and flexible wing aerodynamics, flight dynamics and stability, passive and active mechanisms in stabilization and control, as well as flapping flight in unsteady environments. We further highlight recent advances in biomimetics of flapping-wing MAVs with a specific focus on insect-inspired wing design and fabrication, as well as sensing systems.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'. PMID:27528780

  5. "El Euskera a Mi Me Gusta": Parental Attitudes of Basque Country Immigrants

    Science.gov (United States)

    Torres-Guzman, Maria E.; Etxeberria-Sagastume, Felipa; Intxausti Intxausti, Nahia

    2011-01-01

    Within this study, we examine the nexus of immigrant parents' language attitudes and motivations towards a lesser-spoken, endangered language and the revitalization efforts in the Basque Country, Spain. Attitudes and motivations are conceptualized as multileveled, relational, and dynamically constructed within their immediate and broader…

  6. An Autonomous Flight Safety System

    Science.gov (United States)

    Bull, James B.; Lanzi, Raymond J.

    2007-01-01

    The Autonomous Flight Safety System (AFSS) being developed by NASA s Goddard Space Flight Center s Wallops Flight Facility and Kennedy Space Center has completed two successful developmental flights and is preparing for a third. AFSS has been demonstrated to be a viable architecture for implementation of a completely vehicle based system capable of protecting life and property in event of an errant vehicle by terminating the flight or initiating other actions. It is capable of replacing current human-in-the-loop systems or acting in parallel with them. AFSS is configured prior to flight in accordance with a specific rule set agreed upon by the range safety authority and the user to protect the public and assure mission success. This paper discusses the motivation for the project, describes the method of development, and presents an overview of the evolving architecture and the current status.

  7. Consumers’ attitudes towards green food in China

    DEFF Research Database (Denmark)

    Perrea, Toula; Grunert, Klaus G; Krystallis Krontalis, Athanasios;

    Green food is perceived by Chinese consumers as environmentally friendly and safe to consume. Through a Value-Attitude model, the paper examines the degree to which attitudes towards green food is determined by consumers’ values and their general attitudes towards environment and technology....... The link between collectivism, attitudes towards environment and attitudes towards green food is the strongest one. Collectivism also influences attitudes towards technology, which in turn influence attitudes towards green food. However, the lack of significant relationship between individualism...

  8. Stabilization control of a bumblebee in hovering and forward flight

    Institute of Scientific and Technical Information of China (English)

    Yan Xiong; Mao Sun

    2009-01-01

    Our previous study shows that the hovering and forward flight of a bumblebee do not have inherent stabil-ity (passive stability). But the bumblebees are observed to fly stably. Stabilization control must have been applied. In this study, we investigate the longitudinal stabilization con-trol of the bumblebee. The method of computational fluid dynamics is used to compute the control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion. Controllability analysis shows that at all flight speeds consid-ered, although inherently unstable, the flight is controllable. By feedbacking the state variables, i.e. vertical and horizon-tal velocities, pitching rate and pitch angle (which can be measured by the sensory system of the insect), to produce changes in stroke angle and angle of attack of the wings, the flight can be stabilized, explaining why the bumblebees can fly stably even if they are passively unstable.

  9. Stabilization control of a bumblebee in hovering and forward flight

    Science.gov (United States)

    Xiong, Yan; Sun, Mao

    2009-02-01

    Our previous study shows that the hovering and forward flight of a bumblebee do not have inherent stability (passive stability). But the bumblebees are observed to fly stably. Stabilization control must have been applied. In this study, we investigate the longitudinal stabilization control of the bumblebee. The method of computational fluid dynamics is used to compute the control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion. Controllability analysis shows that at all flight speeds considered, although inherently unstable, the flight is controllable. By feedbacking the state variables, i.e. vertical and horizontal velocities, pitching rate and pitch angle (which can be measured by the sensory system of the insect), to produce changes in stroke angle and angle of attack of the wings, the flight can be stabilized, explaining why the bumblebees can fly stably even if they are passively unstable.

  10. Controlled flight of a biologically inspired, insect-scale robot.

    Science.gov (United States)

    Ma, Kevin Y; Chirarattananon, Pakpong; Fuller, Sawyer B; Wood, Robert J

    2013-05-01

    Flies are among the most agile flying creatures on Earth. To mimic this aerial prowess in a similarly sized robot requires tiny, high-efficiency mechanical components that pose miniaturization challenges governed by force-scaling laws, suggesting unconventional solutions for propulsion, actuation, and manufacturing. To this end, we developed high-power-density piezoelectric flight muscles and a manufacturing methodology capable of rapidly prototyping articulated, flexure-based sub-millimeter mechanisms. We built an 80-milligram, insect-scale, flapping-wing robot modeled loosely on the morphology of flies. Using a modular approach to flight control that relies on limited information about the robot's dynamics, we demonstrated tethered but unconstrained stable hovering and basic controlled flight maneuvers. The result validates a sufficient suite of innovations for achieving artificial, insect-like flight. PMID:23641114

  11. Two-dimensional Insect Flight on an Air-Water Interface is a Chaotic Oscillator

    CERN Document Server

    Mukundarajan, Haripriya; Prakash, Manu

    2014-01-01

    Two-dimensional flapping wing insect flight on an air-water interface provides a successful foraging strategy to explore an ecological niche on the surface of a pond. However, the complex interplay of surface tension, aerodynamic forces, biomechanics and neural control that enables two-dimensional flight is unknown. Here we report the discovery of two-dimensional flight in the waterlily beetle Galerucella nymphaeae, which is the fastest reported propulsion mode for an insect on a fluid interface. Using kinematics derived from high-speed videography coupled with analytical models, we demonstrate that two-dimensional flight is a chaotic interfacial oscillator, thus significantly constraining the possible range of flight parameters. Discovery of this complex dynamics in two-dimensional flight on time scales similar to neural responses indicates the challenge of evolving active flight control on a fluid interface.

  12. NASA - Human Space Flight

    Science.gov (United States)

    Davis, Jeffrey R.

    2006-01-01

    The presentation covers five main topical areas. The first is a description of how things work in the microgravity environment such as convection and sedimentation. The second part describes the effects of microgravity on human physiology. This is followed by a description of the hazards of space flight including the environment, the space craft, and the mission. An overview of biomedical research in space, both on shuttle and ISS is the fourth section of the presentation. The presentation concludes with a history of space flight from Ham to ISS. At CART students (11th and 12th graders from Fresno Unified and Clovis Unified) are actively involved in their education. They work in teams to research real world problems and discover original solutions. Students work on projects guided by academic instructors and business partners. They will have access to the latest technology and will be expected to expand their learning environment to include the community. They will focus their studies around a career area (Professional Sciences, Advanced Communications, Engineering and Product Development, or Global Issues).

  13. New Theory of Flight

    Science.gov (United States)

    Hoffman, Johan; Jansson, Johan; Johnson, Claes

    2016-06-01

    We present a new mathematical theory explaining the fluid mechanics of subsonic flight, which is fundamentally different from the existing boundary layer-circulation theory by Prandtl-Kutta-Zhukovsky formed 100 year ago. The new theory is based on our new resolution of d'Alembert's paradox showing that slightly viscous bluff body flow can be viewed as zero-drag/lift potential flow modified by 3d rotational slip separation arising from a specific separation instability of potential flow, into turbulent flow with nonzero drag/lift. For a wing this separation mechanism maintains the large lift of potential flow generated at the leading edge at the price of small drag, resulting in a lift to drag quotient of size 15-20 for a small propeller plane at cruising speed with Reynolds number {Re≈ 107} and a jumbojet at take-off and landing with {Re≈ 108} , which allows flight at affordable power. The new mathematical theory is supported by computed turbulent solutions of the Navier-Stokes equations with a slip boundary condition as a model of observed small skin friction of a turbulent boundary layer always arising for {Re > 106} , in close accordance with experimental observations over the entire range of angle of attacks including stall using a few millions of mesh points for a full wing-body configuration.

  14. 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.

  15. Stability and control issues associated with lightly loaded rotors autorotating in high advance ratio flight

    Science.gov (United States)

    Rigsby, James Michael

    sensitivities with advance ratio, and advance ratio dependent control cross coupling. Hub moment response to rotor disturbances results in transients where rotor damping is reduced due to low Lock number blades and reduced rotor angular velocity. Experimentally identified frequency response shows dominant low frequency modes with advance ratio dependent damping and the frequencies are on the order of typical airframe modes. Rotor speed response to swashplate control perturbations from trim results in non-linear behavior that is advance ratio dependent, and which stems from cyclic flapping behavior at high advance ratio. Rotor control strategies were developed including the use of variable shaft incidence to achieve rotor speed control with hub moment suppression achieved through cyclic control. Flight dynamics characteristics resulting from the coupling of the rotor and airframe were predicted in flight using a baseline airframe with conventional fixed-wing controls, representative of the current interest in the concept vehicle. Results predicted by linearization of the non-linear models were compared with system identification results using the non-linear simulation as surrogate flight test data. Low frequency rotor response is shown to couple with the vehicle motion for short period and roll mode response to airframe control inputs. The rotor speed mode is shown to couple with short period and long period vehicle modes as the rotor torque balance is sensitive to vehicle speed and attitude changes.

  16. Attitudes towards wind power

    International Nuclear Information System (INIS)

    Planning permission for the construction of a small 'farm' of wind turbines at Delabole (Deli windfarm) had been obtained and it was intended to use this source of renewable energy by generating electricity and selling it to the electrical power companies for distribution through the National Grid. It was important, therefore, to establish just what the attitudes of local residents were to the proposed development. A programme of research was discussed with the developer and it was agreed that an attitude survey would be conducted in the local area in the summer of 1990, before the turbines were erected, and before the tourist season was completely spent in order to obtain the views of visitors as well. A similar survey would then be done one year later, when the Deli windfarm was established and running. In addition, control samples would be taken at these two times in Exeter to give baseline information on attitudes toward this topic. This proposal was put to the developer and agreement was reached with him and the UK Department of Energy who were providing financial support for the research. The results of the research are reported. (author)

  17. Neural Networks for Flight Control

    Science.gov (United States)

    Jorgensen, Charles C.

    1996-01-01

    Neural networks are being developed at NASA Ames Research Center to permit real-time adaptive control of time varying nonlinear systems, enhance the fault-tolerance of mission hardware, and permit online system reconfiguration. In general, the problem of controlling time varying nonlinear systems with unknown structures has not been solved. Adaptive neural control techniques show considerable promise and are being applied to technical challenges including automated docking of spacecraft, dynamic balancing of the space station centrifuge, online reconfiguration of damaged aircraft, and reducing cost of new air and spacecraft designs. Our experiences have shown that neural network algorithms solved certain problems that conventional control methods have been unable to effectively address. These include damage mitigation in nonlinear reconfiguration flight control, early performance estimation of new aircraft designs, compensation for damaged planetary mission hardware by using redundant manipulator capability, and space sensor platform stabilization. This presentation explored these developments in the context of neural network control theory. The discussion began with an overview of why neural control has proven attractive for NASA application domains. The more important issues in control system development were then discussed with references to significant technical advances in the literature. Examples of how these methods have been applied were given, followed by projections of emerging application needs and directions.

  18. Shuttle Risk Progression by Flight

    Science.gov (United States)

    Hamlin, Teri; Kahn, Joe; Thigpen, Eric; Zhu, Tony; Lo, Yohon

    2011-01-01

    Understanding the early mission risk and progression of risk as a vehicle gains insights through flight is important: . a) To the Shuttle Program to understand the impact of re-designs and operational changes on risk. . b) To new programs to understand reliability growth and first flight risk. . Estimation of Shuttle Risk Progression by flight: . a) Uses Shuttle Probabilistic Risk Assessment (SPRA) and current knowledge to calculate early vehicle risk. . b) Shows impact of major Shuttle upgrades. . c) Can be used to understand first flight risk for new programs.

  19. THE IMPACT OF CONSUMERS ATTITUDE TOWARD ADVERTISING ON PRODUCT ATTITUDE

    OpenAIRE

    Comiati Raluca; Plaias Ioan

    2010-01-01

    In the paste decades, marketing researchers tried to understand and determine the impact of advertising on consumers’ attitude toward products or brands. The starting point into the analysis was that the favorable or unfavorable evaluation of advertisement is transferred or associated with the promoted product or brand. This paper is aimed to highlight the manner and the grade in which the consumers’ attitude toward advertising is influencing the attitude toward the advertised product. More t...

  20. Neural adaptive attitude tracking controller for flexible spacecraft

    Institute of Scientific and Technical Information of China (English)

    XIAO Bing; HU Qing-lei; MA Guang-fu

    2010-01-01

    In this paper,a neural network adaptive controller is proposed for attitude tracking of flexible spacecraft in presence of unknown inertial matrix and external disturbance.In this approach,neural network technique is employed to approximate the unknown system dynamics with finite combinations of some basis functions,and a robust controller is also designed to attenuate the effect of approximation error,more specially,the knowledge of angular velocity is not required.In the closed-loop system,Lyapunov stability analysis shows that the attitude trajectories asymptotically follow the reference output trajectories.Finally,simulation results are presented for the attitude tracking of a flexible spacecraft to show the excellent performance of the proposed controller and illustrate its robustness in face of external disturbances and unknown dynamics.

  1. Attitude tracking control for spacecraft formation with time-varying delays and switching topology

    Science.gov (United States)

    Yang, Hongjiu; You, Xiu; Hua, Changchun

    2016-09-01

    This paper investigates attitude dynamic tracking control for spacecraft formation in the presence of unmeasurable velocity information with time-varying delays and switching topology. Based on an extended state observer, a nonlinear attitude tracking control approach is developed for spacecraft attitude model formulated by Euler-Lagrangian equations. The attitude tracking controller allows for external disturbances and absence of angular velocity information. Both auto-stable region techniques and a Lyapunov function approach are developed to prove ultimately bounded tracking. Simulation results demonstrate effectiveness of the nonlinear control techniques proposed in this paper.

  2. 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.

  3. 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

  4. Practical Application of a Subscale Transport Aircraft for Flight Research in Control Upset and Failure Conditions

    Science.gov (United States)

    Cunningham, Kevin; Foster, John V.; Morelli, Eugene A.; Murch, Austin M.

    2008-01-01

    Over the past decade, the goal of reducing the fatal accident rate of large transport aircraft has resulted in research aimed at the problem of aircraft loss-of-control. Starting in 1999, the NASA Aviation Safety Program initiated research that included vehicle dynamics modeling, system health monitoring, and reconfigurable control systems focused on flight regimes beyond the normal flight envelope. In recent years, there has been an increased emphasis on adaptive control technologies for recovery from control upsets or failures including damage scenarios. As part of these efforts, NASA has developed the Airborne Subscale Transport Aircraft Research (AirSTAR) flight facility to allow flight research and validation, and system testing for flight regimes that are considered too risky for full-scale manned transport airplane testing. The AirSTAR facility utilizes dynamically-scaled vehicles that enable the application of subscale flight test results to full scale vehicles. This paper describes the modeling and simulation approach used for AirSTAR vehicles that supports the goals of efficient, low-cost and safe flight research in abnormal flight conditions. Modeling of aerodynamics, controls, and propulsion will be discussed as well as the application of simulation to flight control system development, test planning, risk mitigation, and flight research.

  5. Do birds sleep in flight?

    Science.gov (United States)

    Rattenborg, Niels C.

    2006-09-01

    The following review examines the evidence for sleep in flying birds. The daily need to sleep in most animals has led to the common belief that birds, such as the common swift ( Apus apus), which spend the night on the wing, sleep in flight. The electroencephalogram (EEG) recordings required to detect sleep in flight have not been performed, however, rendering the evidence for sleep in flight circumstantial. The neurophysiology of sleep and flight suggests that some types of sleep might be compatible with flight. As in mammals, birds exhibit two types of sleep, slow-wave sleep (SWS) and rapid eye-movement (REM) sleep. Whereas, SWS can occur in one or both brain hemispheres at a time, REM sleep only occurs bihemispherically. During unihemispheric SWS, the eye connected to the awake hemisphere remains open, a state that may allow birds to visually navigate during sleep in flight. Bihemispheric SWS may also be possible during flight when constant visual monitoring of the environment is unnecessary. Nevertheless, the reduction in muscle tone that usually accompanies REM sleep makes it unlikely that birds enter this state in flight. Upon landing, birds may need to recover the components of sleep that are incompatible with flight. Periods of undisturbed postflight recovery sleep may be essential for maintaining adaptive brain function during wakefulness. The recent miniaturization of EEG recording devices now makes it possible to measure brain activity in flight. Determining if and how birds sleep in flight will contribute to our understanding of a largely unexplored aspect of avian behavior and may also provide insight into the function of sleep.

  6. Nursing student attitudes toward statistics.

    Science.gov (United States)

    Mathew, Lizy; Aktan, Nadine M

    2014-04-01

    Nursing is guided by evidence-based practice. To understand and apply research to practice, nurses must be knowledgeable in statistics; therefore, it is crucial to promote a positive attitude toward statistics among nursing students. The purpose of this quantitative cross-sectional study was to assess differences in attitudes toward statistics among undergraduate nursing, graduate nursing, and undergraduate non-nursing students. The Survey of Attitudes Toward Statistics Scale-36 (SATS-36) was used to measure student attitudes, with higher scores denoting more positive attitudes. The convenience sample was composed of 175 students from a public university in the northeastern United States. Statistically significant relationships were found among some of the key demographic variables. Graduate nursing students had a significantly lower score on the SATS-36, compared with baccalaureate nursing and non-nursing students. Therefore, an innovative nursing curriculum that incorporates knowledge of student attitudes and key demographic variables may result in favorable outcomes.

  7. RURAL CONSUMERS’ ATTITUDE TOWARDS KHADI PRODUCTS

    OpenAIRE

    Mrs.Padmasani; S. Muruganandan; M. Yazhini

    2011-01-01

    In this study the consumers‟ attitude towards khadi products is reviewedthrough Fishbein‟s attitude model. The influence of personal characteristics and purchasepreference factors on the attitude as well as the association between attitude andconsumer‟s satisfaction are examined. This study shows that, overall, the consumers havepositive attitude towards khadi product and also that the consumers who have higherattitude get more satisfaction.

  8. 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.

  9. 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.

  10. STUDENTS ATTITUDE TO INTERDISCIPLINARY RESEARCH

    OpenAIRE

    Ahrens, Andreas; Zaščerinska, Jeļena

    2015-01-01

    Interdisciplinary research helps to turn bi-modal nature of phenomenon into success as interdisciplinary research ensures the synergy between two contrasting modes or forms. However, students’ attitude to interdisciplinary research has not been analysed. The purpose of the contribution is to analyse students’ attitude to interdisciplinary research underpinning elaboration of a hypothesis on ensuring students’ positive attitude to interdisciplinary research within university studies. The meani...

  11. Attitudes towards child sexual abuse

    OpenAIRE

    Tennfjord, Oddfrid Skorpe

    2008-01-01

    The main purpose of the present thesis was to develop a measurement instrument aimed to reveal attitudes towards child sexual abuse, and to measure attitudes and associating personal, social and cultural factors among three different samples of Norwegian adults. Additional aims were to explore the relation between participants’ knowledge-seeking on the one hand, their experiences, attitudes and actual knowledge about abuse on the other hand.Three studies are presented based on the same data m...

  12. Attitude of teenagers towards biology

    OpenAIRE

    Lavtižar, Teja

    2016-01-01

    ROSE project is a comprehensive study in which students' attitudes towards Science and Technology affected by many factors have been examined. In our study, only some aspects have been focused due to a narrower field of biology which has been interested in, and the direction of the attitude between Biology to elementary school students has been checked. The purpose of the master's work has been to determine the attitude of the teenagers to Biology as science and Biology as a school subjec...

  13. 弹载高冲击一体化子母弹子弹飞行姿态测量系统%The Integrative High Impact Embed Bullet Flying Attitude Detection System of Some Shrapnel

    Institute of Scientific and Technical Information of China (English)

    文丰; 任勇峰; 王强

    2012-01-01

    为了测试获取子母弹爆炸抛撒后的子弹飞行姿态,采用基于MEMS惯性测量组合与动态存储测试技术相结合的方法来测试子母弹子弹的飞行姿态,对系统的组成、工作原理和主要关键技术的实现途径进行了详细的介绍.系统以MEMS三维角速度和三维加速度的惯性测量组合为姿态敏感元件,一体化的子母弹子弹飞行姿态测量记录器主要由FLASH存储器、FPGA为中心控制器及多通道高速12位模数转换器等组成.记录器具有多通道、低功耗、体积小、大容量、高精度及嵌入子弹内部随子弹飞行测量等优点.系统试验结果表明:该系统能够准确获取子弹从抛撒到中靶的整个过程的姿态数据.%For getting the bullet attitude of some shrapnel after it is dispersed, the method based on MEMS IMU and the dynamic storage test technology is integrated for testing the bullet attitude of shrapnel. The principle of operation, the system composition and major critical implements is provided. The attitude sense organ is three axis angular velocity transducer and three axis accelerometer, the integrative bullet attitude of some shrapnel recorder is composed by flash memory, FPGA ( the center controller) and multi-channel high speed 12 bit ADC, etc. The merits of the recorder are multi-channel, low power dissipation, small in size but high storage capacity, high-precision and can be embed the bullet flying with it for real attitude detecting. The system test result of the flight test proves that the integrated system can get the flight attitude data, which is the bullet from firing to hitting the target.

  14. A comparative analysis of the influence of weather on the flight altitudes of birds

    NARCIS (Netherlands)

    J. Shamoun-Baranes; E. van Loon; H. van Gasteren; J. van Belle; W. Bouten; L. Buurma

    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

  15. Negative Attitudes, Network and Education

    DEFF Research Database (Denmark)

    Bennett, Patrick; la Cour, Lisbeth; Larsen, Birthe;

    We consider the impact of negative attitudes against immigrants and immigration on educational choice in a search and wage bargaining model including networking. We consider two cases in terms of the importance of negative attitudes againts immigrants for high and low educated individuals and find...... that more negative attitudes against immigrants has a positive impact on education in one case and a negative impact in the other and has no impact on natives. Immigration improves employment perspectives for immigrants and thereby increases immigrant education whereas endogenous negative attitudes lead...

  16. Wages, Amenities and Negative Attitudes

    DEFF Research Database (Denmark)

    Waisman, Gisela; Larsen, Birthe

    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.......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...

  17. In-flight Medical Emergencies

    Directory of Open Access Journals (Sweden)

    Amit Chandra

    2013-09-01

    Full Text Available Introduction: Research and data regarding in-flight medical emergencies during commercial air travel are lacking. Although volunteer medical professionals are often called upon to assist, there are no guidelines or best practices to guide their actions. This paper reviews the literature quantifying and categorizing in-flight medical incidents, discusses the unique challenges posed by the in-flight environment, evaluates the legal aspects of volunteering to provide care, and suggests an approach to managing specific conditions at 30,000 feet.Methods: We conducted a MEDLINE search using search terms relevant to aviation medical emergencies and flight physiology. The reference lists of selected articles were reviewed to identify additional studies.Results: While incidence studies were limited by data availability, syncope, gastrointestinal upset, and respiratory complaints were among the most common medical events reported. Chest pain and cardiovascular events were commonly associated with flight diversion.Conclusion: When in-flight medical emergencies occur, volunteer physicians should have knowledge about the most common in-flight medical incidents, know what is available in on-board emergency medical kits, coordinate their therapy with the flight crew and remote resources, and provide care within their scope of practice. [West J Emerg Med. 2013;14(5:499–504.

  18. JACEE long duration balloon flights

    International Nuclear Information System (INIS)

    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

  19. Comprehensive Evaluation of Attitude and Orbit Estimation Using Actual Earth Magnetic Field Data

    Science.gov (United States)

    Deutschmann, Julie K.; Bar-Itzhack, Itzhack Y.

    2000-01-01

    A single, augmented Extended Kalman Filter (EKF), which simultaneously and autonomously estimates spacecraft attitude and orbit has been developed and successfully tested with real magnetometer and gyro data only. Because the earth magnetic field is a function of time and position, and because time is known quite precisely, the differences between the computed and measured magnetic field components, as measured by the magnetometers throughout the entire spacecraft orbit, are a function of both orbit and attitude errors. Thus, conceivably these differences could be used to estimate both orbit and attitude; an observability study validated this assumption. The results of testing the EKF with actual magnetometer and gyro data, from four satellites supported by the NASA Goddard Space Flight Center (GSFC) Guidance, Navigation, and Control Center, are presented and evaluated. They confirm the assumption that a single EKF can estimate both attitude and orbit when using gyros and magnetometers only.

  20. Interior and exterior ballistics coupled optimization with constraints of attitude control and mechanical-thermal conditions

    Science.gov (United States)

    Liang, Xin-xin; Zhang, Nai-min; Zhang, Yan

    2016-07-01

    For solid launch vehicle performance promotion, a modeling method of interior and exterior ballistics associated optimization with constraints of attitude control and mechanical-thermal condition is proposed. Firstly, the interior and external ballistic models of the solid launch vehicle are established, and the attitude control model of the high wind area and the stage of the separation is presented, and the load calculation model of the drag reduction device is presented, and thermal condition calculation model of flight is presented. Secondly, the optimization model is established to optimize the range, which has internal and external ballistic design parameters as variables selected by sensitivity analysis, and has attitude control and mechanical-thermal conditions as constraints. Finally, the method is applied to the optimal design of a three stage solid launch vehicle simulation with differential evolution algorithm. Simulation results are shown that range capability is improved by 10.8%, and both attitude control and mechanical-thermal conditions are satisfied.

  1. VML 3.0 Reactive Sequencing Objects and Matrix Math Operations for Attitude Profiling

    Science.gov (United States)

    Grasso, Christopher A.; Riedel, Joseph E.

    2012-01-01

    VML (Virtual Machine Language) has been used as the sequencing flight software on over a dozen JPL deep-space missions, most recently flying on GRAIL and JUNO. In conjunction with the NASA SBIR entitled "Reactive Rendezvous and Docking Sequencer", VML version 3.0 has been enhanced to include object-oriented element organization, built-in queuing operations, and sophisticated matrix / vector operations. These improvements allow VML scripts to easily perform much of the work that formerly would have required a great deal of expensive flight software development to realize. Autonomous turning and tracking makes considerable use of new VML features. Profiles generated by flight software are managed using object-oriented VML data constructs executed in discrete time by the VML flight software. VML vector and matrix operations provide the ability to calculate and supply quaternions to the attitude controller flight software which produces torque requests. Using VML-based attitude planning components eliminates flight software development effort, and reduces corresponding costs. In addition, the direct management of the quaternions allows turning and tracking to be tied in with sophisticated high-level VML state machines. These state machines provide autonomous management of spacecraft operations during critical tasks like a hypothetic Mars sample return rendezvous and docking. State machines created for autonomous science observations can also use this sort of attitude planning system, allowing heightened autonomy levels to reduce operations costs. VML state machines cannot be considered merely sequences - they are reactive logic constructs capable of autonomous decision making within a well-defined domain. The state machine approach enabled by VML 3.0 is progressing toward flight capability with a wide array of applicable mission activities.

  2. 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

  3. Cultural evolution: interpersonal influence, issue importance, and the development of shared attitudes in college residence halls.

    Science.gov (United States)

    Cullum, Jerry; Harton, Helen C

    2007-10-01

    This article investigates cultural evolution in four college residence halls. Up to four attitude surveys were completed by 1,252 participants in a semester. Participants' attitudes became more similar to those living closest to them over time as a result of localized interpersonal influence processes. Correlations between attitudes also increased with time as these cultural attributes grew increasingly interdependent. These basic findings support the predictions of dynamic social impact theory. However, these effects were stronger for more important issues even when controlling for discussion. These findings are likely the result of (a) individual-level selective attention to personally important information, (b) greater attitude-behavior consistency for important issues, and/or (c) nonlinear attitude change processes for important issues as suggested by the catastrophe theory of attitudes. These results suggest that intrapsychic processes as well as interpersonal processes contribute to cultural evolution.

  4. Nonlinear and fault-tolerant flight control using multivariate splines

    NARCIS (Netherlands)

    Tol, H.J.; De Visser, C.C.; Van Kampen, E.J.; Chu, Q.P.

    2015-01-01

    This paper presents a study on fault tolerant flight control of a high performance aircraft using multivariate splines. The controller is implemented by making use of spline model based adaptive nonlinear dynamic inversion (NDI). This method, indicated as SANDI, combines NDI control with nonlinear c

  5. A practical scheme for adaptive aircraft flight control systems

    Science.gov (United States)

    Athans, M.; Willner, D.

    1974-01-01

    A flight control system design is presented, that can be implemented by analog hardware, to be used to control an aircraft with uncertain parameters. The design is based upon the use of modern control theory. The ideas are illustrated by considering control of STOL longitudinal dynamics.

  6. Towards a different attitude to uncertainty

    Directory of Open Access Journals (Sweden)

    Guy Pe'er

    2014-10-01

    Full Text Available The ecological literature deals with uncertainty primarily from the perspective of how to reduce it to acceptable levels. However, the current rapid and ubiquitous environmental changes, as well as anticipated rates of change, pose novel conditions and complex dynamics due to which many sources of uncertainty are difficult or even impossible to reduce. These include both uncertainty in knowledge (epistemic uncertainty and societal responses to it. Under these conditions, an increasing number of studies ask how one can deal with uncertainty as it is. Here, we explore the question how to adopt an overall alternative attitude to uncertainty, which accepts or even embraces it. First, we show that seeking to reduce uncertainty may be counterproductive under some circumstances. It may yield overconfidence, ignoring early warning signs, policy- and societal stagnation, or irresponsible behaviour if personal certainty is offered by externalization of environmental costs. We then demonstrate that uncertainty can have positive impacts by driving improvements in knowledge, promoting cautious action, contributing to keeping societies flexible and adaptable, enhancing awareness, support and involvement of the public in nature conservation, and enhancing cooperation and communication. We discuss the risks of employing a certainty paradigm on uncertain knowledge, the potential benefits of adopting an alternative attitude to uncertainty, and the need to implement such an attitude across scales – from adaptive management at the local scale, to the evolving Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES at the global level.

  7. Biology Attitude Scale

    OpenAIRE

    YEŞİLYURT, Selami; GÜL, Şeyda

    2009-01-01

    The aim of this study is to develop a scale determining secondary school stu- dent’s attitude towards biology. For this aim, at first, totally 92 scale items were prepared by reviewing relevant literature. 88 items in this scale were a five-point Likert type scale. 4 of 92 items consisted of demographic variables. The scale was applied to a sample of 109 students randomly selected from two secondary schools in Erzurum. At the end of this application, SPSS 12.0 Statistical Program was used to ...

  8. Optimal magnetic attitude control

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Markley, F.L.

    1999-01-01

    Magnetic torquing is attractive as means of control for small satellites. The actuation principle is to use the interaction between the earth's magnetic field and a magnetic field generated by a coil set in the satellite. This control principle is inherently time-varying, and difficult to use...... 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...

  9. Medical students' attitudes : attitude development in a medical school

    NARCIS (Netherlands)

    Batenburg, Vera

    2001-01-01

    Attitudes of medical students towards patients, psychosocial factors in illness, and care-delivery have been assessed. The influence of (parts of) the medical curriculum has been studied. Students' evaluations of attitude and communication courses have been investigated. The main results were: t

  10. 结合进化算法的稀疏A*算法对动态目标的无人机航迹规划研究%Research on UAV flight path planning for dynamic target based on sparse A * algorithm

    Institute of Scientific and Technical Information of China (English)

    刘群芳; 李军华

    2016-01-01

    In order to solve the problem of unmanned aerial vehicle (UAV) dynamic target path planning, this paper uses the two-level hierarchical planning structure and the hybrid evolutionary algorithm of the sparse A* algorithm and the cultural algorithm (CA) to realize the dynamic UAV path real-time planning under the dynamic target, solves the dynamic path planning problem of avoiding threats and following the target, improves the planning speed and reliability of the track, strengthens the flight safety of UAV.%针对移动目标的无人机航迹规划问题,结合文化算法改进稀疏A*算法解决静态航迹的绕径问题,然后进一步使用混合算法解决目标跟随过程中动态航迹的规划速度和最优路径的平衡选择问题,最终实现不确定环境下跟随目标和威胁躲避的动态航迹实时规划。通过采用静态和动态两级分层规划结构,使用基于稀疏A*算法与文化算法的混合算法实现了动态目标和动态威胁的无人机航迹规划。

  11. 14 CFR 141.41 - Flight simulators, flight training devices, and training aids.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Flight simulators, flight training devices..., Aircraft, and Facilities Requirements § 141.41 Flight simulators, flight training devices, and training... that its flight simulators, flight training devices, training aids, and equipment meet the...

  12. The Development of the Ares I-X Flight Test

    Science.gov (United States)

    Ess, Robert H.

    2008-01-01

    The National Aeronautics and Space Administration (NASA) Constellation Program (CxP) has identified a series of tests to provide insight into the design and development of the Ares I Crew Launch Vehicle (CLV) and the Orion Crew Exploration Vehicle (CEV). Ares I-X was created as the first suborbital development flight test to help meet CxP objectives. The Ares I-X flight vehicle is an early operational model of Ares, with specific emphasis on Ares I and ground operation characteristics necessary to meet Ares I-X flight test objectives. Ares I-X will encompass the design and construction of an entire system that includes the Flight Test Vehicle (FTV) and associated operations. The FTV will be a test model based on the Ares I design. Select design features will be incorporated in the FTV design to emulate the operation of the CLV in order to meet the flight test objectives. The operations infrastructure and processes will be customized for Ares I-X, while still providing data to inform the developers of the launch processing system for Ares/Orion. The FTV is comprised of multiple elements and components that will be developed at different locations. The components will be delivered to the launch/assembly site, Kennedy Space Center (KSC), for assembly of the elements and components into an integrated, flight-ready, launch vehicle. The FTV will fly a prescribed trajectory in order to obtain the necessary data to meet the objectives. Ares I-X will not be commanded or controlled from the ground during flight, but the FTV will be equipped with telemetry systems, a data recording capability and a flight termination system (FTS). The in-flight part of the test includes a trajectory to simulate maximum dynamic pressure during flight and perform a stage separation representative of the CLV. The in-flight test also includes separation of the Upper Stage Simulator (USS) from the First Stage and recovery of the First Stage. The data retrieved from the flight test will be analyzed

  13. Attitudes of university precalculus students toward mathematics.

    Science.gov (United States)

    Alkhateeb, Haitham M; Mji, Andile

    2005-04-01

    To investigate the attitudes of 200 university students (83% freshmen) toward mathematics, a questionnaire was administered to report on their attitudes toward mathematics. Analysis indicated that students studying precalculus had a somewhat positive attitude toward mathematics. PMID:15941096

  14. High School Students' Attitudes Toward Homosexuality.

    Science.gov (United States)

    Price, James H.

    1982-01-01

    A review of research concerning attitudes toward homosexuality and a study of 278 high school students' attitudes toward homosexuality show that males have significantly greater negative attitudes toward homosexuality. Tables display results of the study. (CJ)

  15. An All Electronic, Adaptive, Focusing Schlieren System for Flight Research Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This is a proposal to develop an electronic, focusing schlieren system for flight research based on electronic cameras and spatial light modulators as dynamic...

  16. Formation Flight of Multiple UAVs via Onboard Sensor Information Sharing.

    Science.gov (United States)

    Park, Chulwoo; Cho, Namhoon; Lee, Kyunghyun; Kim, Youdan

    2015-07-17

    To monitor large areas or simultaneously measure multiple points, multiple unmanned aerial vehicles (UAVs) must be flown in formation. To perform such flights, sensor information generated by each UAV should be shared via communications. Although a variety of studies have focused on the algorithms for formation flight, these studies have mainly demonstrated the performance of formation flight using numerical simulations or ground robots, which do not reflect the dynamic characteristics of UAVs. In this study, an onboard sensor information sharing system and formation flight algorithms for multiple UAVs are proposed. The communication delays of radiofrequency (RF) telemetry are analyzed to enable the implementation of the onboard sensor information sharing system. Using the sensor information sharing, the formation guidance law for multiple UAVs, which includes both a circular and close formation, is designed. The hardware system, which includes avionics and an airframe, is constructed for the proposed multi-UAV platform. A numerical simulation is performed to demonstrate the performance of the formation flight guidance and control system for multiple UAVs. Finally, a flight test is conducted to verify the proposed algorithm for the multi-UAV system.

  17. Biomechanics and biomimetics in insect-inspired flight systems

    Science.gov (United States)

    Liu, Hao; Ravi, Sridhar; Kolomenskiy, Dmitry; Tanaka, Hiroto

    2016-01-01

    Insect- and bird-size drones—micro air vehicles (MAV) that can perform autonomous flight in natural and man-made environments are now an active and well-integrated research area. MAVs normally operate at a low speed in a Reynolds number regime of 104–105 or lower, in which most flying animals of insects, birds and bats fly, and encounter unconventional challenges in generating sufficient aerodynamic forces to stay airborne and in controlling flight autonomy to achieve complex manoeuvres. Flying insects that power and control flight by flapping wings are capable of sophisticated aerodynamic force production and precise, agile manoeuvring, through an integrated system consisting of wings to generate aerodynamic force, muscles to move the wings and a control system to modulate power output from the muscles. In this article, we give a selective review on the state of the art of biomechanics in bioinspired flight systems in terms of flapping and flexible wing aerodynamics, flight dynamics and stability, passive and active mechanisms in stabilization and control, as well as flapping flight in unsteady environments. We further highlight recent advances in biomimetics of flapping-wing MAVs with a specific focus on insect-inspired wing design and fabrication, as well as sensing systems. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight’. PMID:27528780

  18. Formation Flight of Multiple UAVs via Onboard Sensor Information Sharing.

    Science.gov (United States)

    Park, Chulwoo; Cho, Namhoon; Lee, Kyunghyun; Kim, Youdan

    2015-01-01

    To monitor large areas or simultaneously measure multiple points, multiple unmanned aerial vehicles (UAVs) must be flown in formation. To perform such flights, sensor information generated by each UAV should be shared via communications. Although a variety of studies have focused on the algorithms for formation flight, these studies have mainly demonstrated the performance of formation flight using numerical simulations or ground robots, which do not reflect the dynamic characteristics of UAVs. In this study, an onboard sensor information sharing system and formation flight algorithms for multiple UAVs are proposed. The communication delays of radiofrequency (RF) telemetry are analyzed to enable the implementation of the onboard sensor information sharing system. Using the sensor information sharing, the formation guidance law for multiple UAVs, which includes both a circular and close formation, is designed. The hardware system, which includes avionics and an airframe, is constructed for the proposed multi-UAV platform. A numerical simulation is performed to demonstrate the performance of the formation flight guidance and control system for multiple UAVs. Finally, a flight test is conducted to verify the proposed algorithm for the multi-UAV system. PMID:26193281

  19. 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

  20. Christian attitude in business

    Directory of Open Access Journals (Sweden)

    J M Vorster

    2006-09-01

    Full Text Available The beginning of the twenty-first century faces new challenges in the field of business ethics.� Totally new macro-ethical challenges have arisen and they have already inspired constant ethical reflection. Two major developments in the field of economics paved the way for this new interest in business ethics: the total dominance of the market driven economy and economic globalization. This article investigates the ethical challenges posed by this new environment from a Christian ethical perspective. Firstly norms are formulated flowing from the paradigm of Christian attitude as a manifestation of the attitude of Christ. These are love, stewardship, self-denial and obedience to God. These norms are then applied to the following modern-day issues in the field of business ethics: the challenge of globalization, respect for basic human rights, remuneration, the corporation as a moral model, the need for self-evaluation, political responsibility and environmental concern. In conclusion I attempt to define the role of Christians and Christian churches in transforming corporations into moral agents.