WorldWideScience

Sample records for based autonomous flight

  1. GPS Based Autonomous Flight Control System for an Unmanned Airship

    Directory of Open Access Journals (Sweden)

    Vishnu G Nair,

    2014-01-01

    Full Text Available An unmanned airship, also known as a Unmanned aircraft System (UAS or a remotely piloted aircraft is a machine which functions either by the remote control of a navigator or pilot. The unmanned airship uses the autonomous flight, navigation and guidance based on the telemetry command of ground station. The Autonomous Flight Control System (AFCS [1] plays a key role in achieving the given requirements and missions. This paper introduces the overall design architecture of the hardware and software of the flight control systems in a 50m long unmanned airship

  2. Autonomous Ornithopter Flight with Sensor-Based Seeking Behavior

    OpenAIRE

    2011-01-01

    This thesis presents the design of autonomous flight control algorithms for a flapping-wing aerial robot with onboard sensing and computational resources. We use a 13 gram ornithopter with biologically inspired clap-and-fling mechanism. For autonomous flight control, we have developed 1.0 gram control electronics integrated with a microcontroller, inertial and visual sensors, communication electronics, and motor drivers. We have also developed a simplified aerodynamic model of ornithopter fli...

  3. 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.

  4. Adaptive estimation and control with application to vision-based autonomous formation flight

    Science.gov (United States)

    Sattigeri, Ramachandra

    2007-05-01

    Modern Unmanned Aerial Vehicles (UAVs) are equipped with vision sensors because of their light-weight, low-cost characteristics and also their ability to provide a rich variety of information of the environment in which the UAVs are navigating in. The problem of vision based autonomous flight is very difficult and challenging since it requires bringing together concepts from image processing and computer vision, target tracking and state estimation, and flight guidance and control. This thesis focuses on the adaptive state estimation, guidance and control problems involved in vision-based formation flight. Specifically, the thesis presents a composite adaptation approach to the partial state estimation of a class of nonlinear systems with unmodeled dynamics. In this approach, a linear time-varying Kalman filter is the nominal state estimator which is augmented by the output of an adaptive neural network (NN) that is trained with two error signals. The benefit of the proposed approach is in its faster and more accurate adaptation to the modeling errors over a conventional approach. The thesis also presents two approaches to the design of adaptive guidance and control (G&C) laws for line-of-sight formation flight. In the first approach, the guidance and autopilot systems are designed separately and then combined together by assuming time-scale separation. The second approach is based on integrating the guidance and autopilot design process. The developed G&C laws using both approaches are adaptive to unmodeled leader aircraft acceleration and to own aircraft aerodynamic uncertainties. The thesis also presents theoretical justification based on Lyapunov-like stability analysis for integrating the adaptive state estimation and adaptive G&C designs. All the developed designs are validated in nonlinear, 6DOF fixed-wing aircraft simulations. Finally, the thesis presents a decentralized coordination strategy for vision-based multiple-aircraft formation control. In this

  5. Autonomous Hovering Flight of a Small Helicopter

    Science.gov (United States)

    Ohkura, Akihiro; Tokutake, Hiroshi; Sunada, Shigeru

    During the 20th century, aircraft were only used for transportation. If aircraft can be made small and lightweight, however, they can become tools to assist in everyday life. We developed a small, lightweight co-axial helicopter with a rotor diameter of about 30cm. The mechanisms for varying cyclic pitch of the upper and lower rotors, which are used in the coaxial helicopter for entertainment, are adopted in our develop helicopter. Our developed helicopter is equipped with a flight control system for the attitude and position, which is composed of a micro computer and some sensors. And the helicopter can make autonomous hovering flight just measuring the height and the distances from the walls. The weight of the helicopter is no more than 200g and this helicopter is the lightest helicopter for an autonomous hovering flight among the helicopters where all control systems are onboard, as far as the authors know.

  6. Control Design and Performance Analysis for Autonomous Formation Flight Experimentss

    Science.gov (United States)

    Rice, Caleb Michael

    Autonomous Formation Flight is a key approach for reducing greenhouse gas emissions and managing traffic in future high density airspace. Unmanned Aerial Vehicles (UAV's) have made it possible for the physical demonstration and validation of autonomous formation flight concepts inexpensively and eliminates the flight risk to human pilots. This thesis discusses the design, implementation, and flight testing of three different formation flight control methods, Proportional Integral and Derivative (PID); Fuzzy Logic (FL); and NonLinear Dynamic Inversion (NLDI), and their respective performance behavior. Experimental results show achievable autonomous formation flight and performance quality with a pair of low-cost unmanned research fixed wing aircraft and also with a solo vertical takeoff and landing (VTOL) quadrotor.

  7. Safe and Autonomous Drones for Urban Flight

    Science.gov (United States)

    Krishnakumar, Kalmanje

    2016-01-01

    Autonomous vehicles are no longer futuristic technology; in fact, there are already cars with self-driving features on the road. Over the next five years, the connected vehicles will disrupt the entire automotive and UAS ecosystems. The industry will undergo fundamental change as semi-autonomous driving and flying emerges, followed by an eventual shift to full autonomy.

  8. Mapping a Path to Autonomous Flight in the National Airspace

    Science.gov (United States)

    Lodding, Kenneth N.

    2011-01-01

    The introduction of autonomous flight, whether military, commercial, or civilian, into the National Airspace System (NAS) will present significant challenges. Minimizing the impact and preventing the changes from becoming disruptive, rather than an enhancing technology will not be without difficulty. From obstacle detection and avoidance to real-time verification and validation of system behavior, there are significant problems which must be solved prior to the general acceptance of autonomous systems. This paper examines some of the key challenges and the multi-disciplinary collaboration which must occur for autonomous systems to be accepted as equal partners in the NAS.

  9. Autonomous Airborne Refueling Demonstration: Phase I Flight-Test Results

    Science.gov (United States)

    Dibley, Ryan P.; Allen, Michael J.; Nabaa, Nassib

    2007-01-01

    The first phase of the Autonomous Airborne Refueling Demonstration (AARD) project was completed on August 30, 2006. The goal of this 15-month effort was to develop and flight-test a system to demonstrate an autonomous refueling engagement using the Navy style hose-and-drogue air-to-air refueling method. The prime contractor for this Defense Advanced Research Projects Agency (DARPA) sponsored program was Sierra Nevada Corporation (SNC), Sparks, Nevada. The responsible flight-test organization was the National Aeronautics and Space Administration (NASA) Dryden Flight Research Center (DFRC), Edwards, California, which also provided the F/A-18 receiver airplane (McDonnell Douglas, now The Boeing Company, Chicago, Illinois). The B-707-300 tanker airplane (The Boeing Company) was contracted through Omega Aerial Refueling Services, Inc., Alexandria, Virginia, and the optical tracking system was contracted through OCTEC Ltd., Bracknell, Berkshire, United Kingdom. Nine research flights were flown, testing the functionality and performance of the system in a stepwise manner, culminating in the plug attempts on the final flight. Relative position keeping was found to be very stable and accurate. The receiver aircraft was capable of following the tanker aircraft through turns while maintaining its relative position. During the last flight, six capture attempts were made, two of which were successful. The four misses demonstrated excellent characteristics, the receiver retreating from the drogue in a controlled, safe, and predictable manner that precluded contact between the drogue and the receiver aircraft. The position of the receiver aircraft when engaged and in position for refueling was found to be 5.5 to 8.5 ft low of the ideal position. The controller inputs to the F/A-18 were found to be extremely small.

  10. Autonomous Airborne Refueling Demonstration, Phase I Flight-Test Results

    Science.gov (United States)

    Dibley, Ryan P.; Allen, Michael J.; Nabaa, Nassib

    2007-01-01

    The first phase of the Autonomous Airborne Refueling Demonstration (AARD) project was completed on August 30, 2006. The goal of this 15-month effort was to develop and flight-test a system to demonstrate an autonomous refueling engagement using the Navy style hose-and-drogue air-to-air refueling method. The prime contractor for this Defense Advanced Research Projects Agency (DARPA) sponsored program was Sierra Nevada Corporation (SNC), Sparks, Nevada. The responsible flight-test organization was the NASA Dryden Flight Research Center (DFRC), Edwards, California, which also provided the F/A-18 receiver airplane (McDonnell Douglas, now The Boeing Company, Chicago, Illinois). The B-707-300 tanker airplane (The Boeing Company) was contracted through Omega Aerial Refueling Services, Inc., Alexandria, Virginia, and the optical tracking system was contracted through OCTEC Ltd., Bracknell, Berkshire, United Kingdom. Nine research flights were flown, testing the functionality and performance of the system in a stepwise manner, culminating in the plug attempts on the final flight. Relative position keeping was found to be very stable and accurate. The receiver aircraft was capable of following the tanker aircraft through turns while maintaining its relative position. During the last flight, six capture attempts were made, two of which were successful. The four misses demonstrated excellent characteristics, the receiver retreating from the drogue in a controlled, safe, and predictable manner that precluded contact between the drogue and the receiver aircraft. The position of the receiver aircraft when engaged and in position for refueling was found to be 5.5 to 8.5 ft low of the ideal position. The controller inputs to the F/A-18 were found to be extremely small

  11. Electrogastrographic and autonomic responses during oculovestibular recoupling in flight simulation.

    Science.gov (United States)

    Cevette, Michael J; Pradhan, Gaurav N; Cocco, Daniela; Crowell, Michael D; Galea, Anna M; Bartlett, Jennifer; Stepanek, Jan

    2014-01-01

    Simulator sickness causes vestibulo-autonomic responses that increase sympathetic activity and decrease parasympathetic activity. The purpose of the study was to quantify these responses through electrogastrography and cardiac interbeat intervals during flight simulation. There were 29 subjects that were randomly assigned to 2 parallel arms: (1) oculovestibular recoupling, where galvanic vestibular stimulation was synchronous with the visual field; and (2) control. Electrogastrography and interbeat interval data were collected during baseline, simulation, and post-simulation periods. A simulator sickness questionnaire was administered. Statistically significant differences were observed in percentage of recording time with the dominant frequency of electrogastrography in normogastric and bradygastric domains between the oculovestibular recoupling and control groups. Normogastria was dominant during simulation in the oculovestibular recoupling group. In the control group, the percentage of recording time with the dominant frequency decreased by 22% in normogastria and increased by 20% in bradygastria. The percentage change of the dominant power instability coefficient from baseline to simulation was 26% in the oculovestibular recoupling group vs. 108% in the control group. The power of high-frequency components for interbeat intervals did not change significantly in the oculovestibular recoupling group and was decreased during simulation in the control group. Electrogastrography and interbeat intervals are sensitive indices of autonomic changes in subjects undergoing flight simulation. These data demonstrate the potential of oculovestibular recoupling to stabilize gastric activity and cardiac autonomic changes altered during simulator and motion sickness.

  12. Autonomous Flight Rules Concept: User Implementation Costs and Strategies

    Science.gov (United States)

    Cotton, William B.; Hilb, Robert

    2014-01-01

    The costs to implement Autonomous Flight Rules (AFR) were examined for estimates in acquisition, installation, training and operations. The user categories were airlines, fractional operators, general aviation and unmanned aircraft systems. Transition strategies to minimize costs while maximizing operational benefits were also analyzed. The primary cost category was found to be the avionics acquisition. Cost ranges for AFR equipment were given to reflect the uncertainty of the certification level for the equipment and the extent of existing compatible avionics in the aircraft to be modified.

  13. Pilot In Command: A Feasibility Assessment of Autonomous Flight Management Operations

    Science.gov (United States)

    Wing, David J.; Ballin, Mark G.; Krishnamurthy, Karthik

    2004-01-01

    Several years of NASA research have produced the air traffic management operational concept of Autonomous Flight Management with high potential for operational feasibility, significant system and user benefits, and safety. Among the chief potential benefits are demand-adaptive or scalable capacity, user flexibility and autonomy that may finally enable truly successful business strategies, and compatibility with current-day operations such that the implementation rate can be driven from within the user community. A concept summary of Autonomous Flight Management is provided, including a description of how these operations would integrate in shared airspace with existing ground-controlled flight operations. The mechanisms enabling the primary benefits are discussed, and key findings of a feasibility assessment of airborne autonomous operations are summarized. Concept characteristics that impact safety are presented, and the potential for initially implementing Autonomous Flight Management is discussed.

  14. Radar based autonomous sensor module

    Science.gov (United States)

    Styles, Tim

    2016-10-01

    Most surveillance systems combine camera sensors with other detection sensors that trigger an alert to a human operator when an object is detected. The detection sensors typically require careful installation and configuration for each application and there is a significant burden on the operator to react to each alert by viewing camera video feeds. A demonstration system known as Sensing for Asset Protection with Integrated Electronic Networked Technology (SAPIENT) has been developed to address these issues using Autonomous Sensor Modules (ASM) and a central High Level Decision Making Module (HLDMM) that can fuse the detections from multiple sensors. This paper describes the 24 GHz radar based ASM, which provides an all-weather, low power and license exempt solution to the problem of wide area surveillance. The radar module autonomously configures itself in response to tasks provided by the HLDMM, steering the transmit beam and setting range resolution and power levels for optimum performance. The results show the detection and classification performance for pedestrians and vehicles in an area of interest, which can be modified by the HLDMM without physical adjustment. The module uses range-Doppler processing for reliable detection of moving objects and combines Radar Cross Section and micro-Doppler characteristics for object classification. Objects are classified as pedestrian or vehicle, with vehicle sub classes based on size. Detections are reported only if the object is detected in a task coverage area and it is classified as an object of interest. The system was shown in a perimeter protection scenario using multiple radar ASMs, laser scanners, thermal cameras and visible band cameras. This combination of sensors enabled the HLDMM to generate reliable alerts with improved discrimination of objects and behaviours of interest.

  15. 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.

  16. LEO AUTONOMOUS NAVIGATION BASED ON IMAGE MOTION

    Institute of Scientific and Technical Information of China (English)

    DUANFang; LIUJian-ye; YUFeng

    2005-01-01

    A method of LEO autonomous navigation is presented based on the nonlinear satellite velocity relative to the earth. The velocity is detected by a high-speed camera, with the attitude information detected by a star sensor. Compared with traditional autonomous navigation by landmark identification, the satellite velocity relarive to the earth is obtained by correlativity analysis of images. It does not need to recognize ground objects or views. Since it is not necessary to pre-store the database of ground marks, lots of memory space can be saved.The state and observation equations are constructed, and the filtering is processed by the Kalman filter. Simulation results show that the system has high autonomous navigation precision in LEO autonomous navigation.

  17. Cardiovascular autonomic adaptation in lunar and martian gravity during parabolic flight.

    Science.gov (United States)

    Widjaja, Devy; Vandeput, Steven; Van Huffel, Sabine; Aubert, André E

    2015-06-01

    Weightlessness has a well-known effect on the autonomic control of the cardiovascular system. With future missions to Mars in mind, it is important to know what the effect of partial gravity is on the human body. We aim to study the autonomic response of the cardiovascular system to partial gravity levels, as present on the Moon and on Mars, during parabolic flight. ECG and blood pressure were continuously recorded during parabolic flight. A temporal analysis of blood pressure and heart rate to changing gravity was conducted to study the dynamic response. In addition, cardiovascular autonomic control was quantified by means of heart rate (HR) and blood pressure (BP) variability measures. Zero and lunar gravity presented a biphasic cardiovascular response, while a triphasic response was noted during martian gravity. Heart rate and blood pressure are positively correlated with gravity, while the general variability of HR and BP, as well as vagal indices showed negative correlations with increasing gravity. However, the increase in vagal modulation during weightlessness is not in proportion when compared to the increase during partial gravity. Correlations were found between the gravity level and modulations in the autonomic nervous system during parabolic flight. Nevertheless, with future Mars missions in mind, more studies are needed to use these findings to develop appropriate countermeasures.

  18. Autonomous Robot Navigation based on Visual Landmarks

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2005-01-01

    autonomous navigation and self-localization using automatically selected landmarks. The thesis investigates autonomous robot navigation and proposes a new method which benefits from the potential of the visual sensor to provide accuracy and reliability to the navigation process while relying on naturally...... update of the estimated robot position while the robot is moving. In order to make the system autonomous, both acquisition and observation of landmarks have to be carried out automatically. The thesis consequently proposes a method for learning and navigation of a working environment and it explores...... of the proposed method is based on a system with a simple setup. The novelty and potentiality, are in combining algorithms for panoramic view-synthesis, attention selection, stereo reconstruction, triangulation, optimal triplet selection, and image-based rendering. Experiments demonstrate that the system can...

  19. Autonomous Robot Navigation based on Visual Landmarks

    DEFF Research Database (Denmark)

    Livatino, Salvatore

    2005-01-01

    autonomous navigation and self-localization using automatically selected landmarks. The thesis investigates autonomous robot navigation and proposes a new method which benefits from the potential of the visual sensor to provide accuracy and reliability to the navigation process while relying on naturally...... available environment features (natural landmarks). The goal is also to integrate techniques and algorithms (also related to other research field) in the same navigation system, in order to improve localization performance and system autonomy. The proposed localization strategy is based on a continuous...... update of the estimated robot position while the robot is moving. In order to make the system autonomous, both acquisition and observation of landmarks have to be carried out automatically. The thesis consequently proposes a method for learning and navigation of a working environment and it explores...

  20. A multimodal micro air vehicle for autonomous flight in near-earth environments

    Science.gov (United States)

    Green, William Edward

    Reconnaissance, surveillance, and search-and-rescue missions in near-Earth environments such as caves, forests, and urban areas pose many new challenges to command and control (C2) teams. Of great significance is how to acquire situational awareness when access to the scene is blocked by enemy fire, rubble, or other occlusions. Small bird-sized aerial robots are expendable and can fly over obstacles and through small openings to assist in the acquisition and distribution of intelligence. However, limited flying space and densely populated obstacle fields requires a vehicle that is capable of hovering, but also maneuverable. A secondary flight mode was incorporated into a fixed-wing aircraft to preserve its maneuverability while adding the capability of hovering. An inertial measurement sensor and onboard flight control system were interfaced and used to transition the hybrid prototype from cruise to hover flight and sustain a hover autonomously. Furthermore, the hovering flight mode can be used to maneuver the aircraft through small openings such as doorways. An ultrasonic and infrared sensor suite was designed to follow exterior building walls until an ingress route was detected. Reactive control was then used to traverse the doorway and gather reconnaissance. Entering a dangerous environment to gather intelligence autonomously will provide an invaluable resource to any C2 team. The holistic approach of platform development, sensor suite design, and control serves as the philosophy of this work.

  1. Insect-Based Vision for Autonomous Vehicles: A Feasibility Study

    Science.gov (United States)

    Srinivasan, Mandyam V.

    1999-01-01

    The aims of the project were to use a high-speed digital video camera to pursue two questions: (1) To explore the influence of temporal imaging constraints on the performance of vision systems for autonomous mobile robots; (2) To study the fine structure of insect flight trajectories in order to better understand the characteristics of flight control, orientation and navigation.

  2. Autonomous Inspection of Electrical Transmission Structures with Airborne UV Sensors - NASA Report on Dominion Virginia Power Flights of November 2016

    Science.gov (United States)

    Moore, Andrew J.; Schubert, Matthew; Nicholas Rymer

    2017-01-01

    The report details test and measurement flights to demonstrate autonomous UAV inspection of high voltage electrical transmission structures. A UAV built with commercial, off-the-shelf hardware and software, supplemented with custom sensor logging software, measured ultraviolet emissions from a test generator placed on a low-altitude substation and a medium-altitude switching tower. Since corona discharge precedes catastrophic electrical faults on high-voltage structures, detection and geolocation of ultraviolet emissions is needed to develop a UAV-based self-diagnosing power grid. Signal readings from an onboard ultraviolet sensor were validated during flight with a commercial corona camera. Geolocation was accomplished with onboard GPS; the UAV position was logged to a local ground station and transmitted in real time to a NASA server for tracking in the national airspace.

  3. Wavefront Propagation and Fuzzy Based Autonomous Navigation

    Directory of Open Access Journals (Sweden)

    Adel Al-Jumaily

    2005-06-01

    Full Text Available Path planning and obstacle avoidance are the two major issues in any navigation system. Wavefront propagation algorithm, as a good path planner, can be used to determine an optimal path. Obstacle avoidance can be achieved using possibility theory. Combining these two functions enable a robot to autonomously navigate to its destination. This paper presents the approach and results in implementing an autonomous navigation system for an indoor mobile robot. The system developed is based on a laser sensor used to retrieve data to update a two dimensional world model of therobot environment. Waypoints in the path are incorporated into the obstacle avoidance. Features such as ageing of objects and smooth motion planning are implemented to enhance efficiency and also to cater for dynamic environments.

  4. Agent-based Multimodal Interface for Dynamically Autonomous Mobile Robots

    Science.gov (United States)

    2003-01-01

    Agent-based Multimodal Interface for Dynamically Autonomous Mobile Robots Donald Sofge, Magdalena Bugajska, William Adams, Dennis...computing paradigm for integrated distributed artificial intelligence systems on autonomous mobile robots (Figure 1). Figure 1 – CoABS Grid...Architecture for Dynamically Autonomous Mobile Robots The remainder of the paper is organized as follows. Section 2 describes our integrated AI

  5. Free-Flight Terrestrial Rocket Lander Demonstration for NASA's Autonomous Landing and Hazard Avoidance Technology (ALHAT) System

    Science.gov (United States)

    Rutishauser, David K.; Epp, Chirold; Robertson, Ed

    2012-01-01

    The Autonomous Landing Hazard Avoidance Technology (ALHAT) Project is chartered to develop and mature to a Technology Readiness Level (TRL) of six an autonomous system combining guidance, navigation and control with terrain sensing and recognition functions for crewed, cargo, and robotic planetary landing vehicles. The ALHAT System must be capable of identifying and avoiding surface hazards to enable a safe and accurate landing to within tens of meters of designated and certified landing sites anywhere on a planetary surface under any lighting conditions. Since its inception in 2006, the ALHAT Project has executed four field test campaigns to characterize and mature sensors and algorithms that support real-time hazard detection and global/local precision navigation for planetary landings. The driving objective for Government Fiscal Year 2012 (GFY2012) is to successfully demonstrate autonomous, real-time, closed loop operation of the ALHAT system in a realistic free flight scenario on Earth using the Morpheus lander developed at the Johnson Space Center (JSC). This goal represents an aggressive target consistent with a lean engineering culture of rapid prototyping and development. This culture is characterized by prioritizing early implementation to gain practical lessons learned and then building on this knowledge with subsequent prototyping design cycles of increasing complexity culminating in the implementation of the baseline design. This paper provides an overview of the ALHAT/Morpheus flight demonstration activities in GFY2012, including accomplishments, current status, results, and lessons learned. The ALHAT/Morpheus effort is also described in the context of a technology path in support of future crewed and robotic planetary exploration missions based upon the core sensing functions of the ALHAT system: Terrain Relative Navigation (TRN), Hazard Detection and Avoidance (HDA), and Hazard Relative Navigation (HRN).

  6. In flight image processing on multi-rotor aircraft for autonomous landing

    Science.gov (United States)

    Henry, Richard, Jr.

    An estimated $6.4 billion was spent during the year 2013 on developing drone technology around the world and is expected to double in the next decade. However, drone applications typically require strong pilot skills, safety, responsibilities and adherence to regulations during flight. If the flight control process could be safer and more reliable in terms of landing, it would be possible to further develop a wider range of applications. The objective of this research effort is to describe the design and evaluation of a fully autonomous Unmanned Aerial system (UAS), specifically a four rotor aircraft, commonly known as quad copter for precise landing applications. The full landing autonomy is achieved by image processing capabilities during flight for target recognition by employing the open source library OpenCV. In addition, all imaging data is processed by a single embedded computer that estimates a relative position with respect to the target landing pad. Results shows a reduction on the average offset error by 67.88% in comparison to the current return to lunch (RTL) method which only relies on GPS positioning. The present work validates the need for relying on image processing for precise landing applications instead of the inexact method of a commercial low cost GPS dependency.

  7. Autonomous Rule Based Robot Navigation In Orchards

    DEFF Research Database (Denmark)

    Andersen, Jens Christian; Ravn, Ole; Andersen, Nils Axel

    2010-01-01

    Orchard navigation using sensor-based localization and exible mission management facilitates successful missions independent of the Global Positioning System (GPS). This is especially important while driving between tight tree rows where the GPS coverage is poor. This paper suggests localization ......, obstacle avoidance, path planning and drive control. The system is tested successfully using a Hako 20 kW tractor during autonomous missions in both cherry and apple orchards with mission length of up to 2.3 km including the headland turns.......Orchard navigation using sensor-based localization and exible mission management facilitates successful missions independent of the Global Positioning System (GPS). This is especially important while driving between tight tree rows where the GPS coverage is poor. This paper suggests localization...

  8. Behavior-Based Power Management in Autonomous Mobile Robots

    Science.gov (United States)

    2008-03-27

    Behavior-Based Power Management In Autonomous Mobile Robots THESIS Charles A. Fetzek, First Lieutenant, USAF AFIT/GCE/ENG/08-05 DEPARTMENT OF THE AIR...of Defense, or the United States Government. AFIT/GCE/ENG/08-05 Behavior-Based Power Management In Autonomous Mobile Robots THESIS Presented to the...Management In Autonomous Mobile Robots Charles A. Fetzek, B.S.C.E. First Lieutenant, USAF Approved: /signed/ 4 Mar 2008 Dr. Gilbert L. Peterson (Chairman

  9. Flexible Wing Base Micro Aerial Vehicles: Towards Flight Autonomy: Vision-Based Horizon Detection for Micro Air Vehicles

    Science.gov (United States)

    Nechyba, Michael C.; Ettinger, Scott M.; Ifju, Peter G.; Wazak, Martin

    2002-01-01

    Recently substantial progress has been made towards design building and testifying remotely piloted Micro Air Vehicles (MAVs). This progress in overcoming the aerodynamic obstacles to flight at very small scales has, unfortunately, not been matched by similar progress in autonomous MAV flight. Thus, we propose a robust, vision-based horizon detection algorithm as the first step towards autonomous MAVs. In this paper, we first motivate the use of computer vision for the horizon detection task by examining the flight of birds (biological MAVs) and considering other practical factors. We then describe our vision-based horizon detection algorithm, which has been demonstrated at 30 Hz with over 99.9% correct horizon identification, over terrain that includes roads, buildings large and small, meadows, wooded areas, and a lake. We conclude with some sample horizon detection results and preview a companion paper, where the work discussed here forms the core of a complete autonomous flight stability system.

  10. 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.

  11. Autonomous robot behavior based on neural networks

    Science.gov (United States)

    Grolinger, Katarina; Jerbic, Bojan; Vranjes, Bozo

    1997-04-01

    The purpose of autonomous robot is to solve various tasks while adapting its behavior to the variable environment, expecting it is able to navigate much like a human would, including handling uncertain and unexpected obstacles. To achieve this the robot has to be able to find solution to unknown situations, to learn experienced knowledge, that means action procedure together with corresponding knowledge on the work space structure, and to recognize working environment. The planning of the intelligent robot behavior presented in this paper implements the reinforcement learning based on strategic and random attempts for finding solution and neural network approach for memorizing and recognizing work space structure (structural assignment problem). Some of the well known neural networks based on unsupervised learning are considered with regard to the structural assignment problem. The adaptive fuzzy shadowed neural network is developed. It has the additional shadowed hidden layer, specific learning rule and initialization phase. The developed neural network combines advantages of networks based on the Adaptive Resonance Theory and using shadowed hidden layer provides ability to recognize lightly translated or rotated obstacles in any direction.

  12. MMW radar enhanced vision systems: the Helicopter Autonomous Landing System (HALS) and Radar-Enhanced Vision System (REVS) are rotary and fixed wing enhanced flight vision systems that enable safe flight operations in degraded visual environments

    Science.gov (United States)

    Cross, Jack; Schneider, John; Cariani, Pete

    2013-05-01

    Sierra Nevada Corporation (SNC) has developed rotary and fixed wing millimeter wave radar enhanced vision systems. The Helicopter Autonomous Landing System (HALS) is a rotary-wing enhanced vision system that enables multi-ship landing, takeoff, and enroute flight in Degraded Visual Environments (DVE). HALS has been successfully flight tested in a variety of scenarios, from brown-out DVE landings, to enroute flight over mountainous terrain, to wire/cable detection during low-level flight. The Radar Enhanced Vision Systems (REVS) is a fixed-wing Enhanced Flight Vision System (EFVS) undergoing prototype development testing. Both systems are based on a fast-scanning, threedimensional 94 GHz radar that produces real-time terrain and obstacle imagery. The radar imagery is fused with synthetic imagery of the surrounding terrain to form a long-range, wide field-of-view display. A symbology overlay is added to provide aircraft state information and, for HALS, approach and landing command guidance cuing. The combination of see-through imagery and symbology provides the key information a pilot needs to perform safe flight operations in DVE conditions. This paper discusses the HALS and REVS systems and technology, presents imagery, and summarizes the recent flight test results.

  13. Safe Autonomous Flight Environment (SAFE50) for the Notional Last 50 ft of Operation of 55 lb Class of UAS

    Science.gov (United States)

    Krishnakumar, Kalmanje; Kopardekar, Parimal; Ippolito, Corey; Melton, John E.; Stepanyan, Vahram; Sankararaman, Shankar; Nikaido, Ben

    2017-01-01

    The most difficult phase of small Unmanned Aerial System (sUAS) deployment is autonomous operations below the notional 50 ft in urban landscapes. Understanding the feasibility of safely flying sUAS autonomously below 50 ft is a game changer for many civilian applications. This paper outlines three areas of research currently underway which address key challenges for flight in the urban landscape. These are: (1) Off-line and On-board wind estimation and accommodation; (2) Real-time trajectory planning via characterization of obstacles using a LIDAR; (3) On-board information fusion for real-time decision-making and safe trajectory generation.

  14. A Vision-Based Method for Autonomous Landing of a Rotor-Craft Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Z. Yuan

    2006-01-01

    Full Text Available This article introduces a real-time vision-based method for guided autonomous landing of a rotor-craft unmanned aerial vehicle. In the process of designing the pattern of landing target, we have fully considered how to make this easier for simplified identification and calibration. A linear algorithm was also applied using a three-dimensional structure estimation in real time. In addition, multiple-view vision technology is utilized to calibrate intrinsic parameters of camera online, so calibration prior to flight is unnecessary and the focus of camera can be changed freely in flight, thus upgrading the flexibility and practicality of the method.

  15. An autonomous vision-based mobile robot

    Science.gov (United States)

    Baumgartner, Eric Thomas

    This dissertation describes estimation and control methods for use in the development of an autonomous mobile robot for structured environments. The navigation of the mobile robot is based on precise estimates of the position and orientation of the robot within its environment. The extended Kalman filter algorithm is used to combine information from the robot's drive wheels with periodic observations of small, wall-mounted, visual cues to produce the precise position and orientation estimates. The visual cues are reliably detected by at least one video camera mounted on the mobile robot. Typical position estimates are accurate to within one inch. A path tracking algorithm is also developed to follow desired reference paths which are taught by a human operator. Because of the time-independence of the tracking algorithm, the speed that the vehicle travels along the reference path is specified independent from the tracking algorithm. The estimation and control methods have been applied successfully to two experimental vehicle systems. Finally, an analysis of the linearized closed-loop control system is performed to study the behavior and the stability of the system as a function of various control parameters.

  16. Autonomous entropy-based intelligent experimental design

    Science.gov (United States)

    Malakar, Nabin Kumar

    2011-07-01

    The aim of this thesis is to explore the application of probability and information theory in experimental design, and to do so in a way that combines what we know about inference and inquiry in a comprehensive and consistent manner. Present day scientific frontiers involve data collection at an ever-increasing rate. This requires that we find a way to collect the most relevant data in an automated fashion. By following the logic of the scientific method, we couple an inference engine with an inquiry engine to automate the iterative process of scientific learning. The inference engine involves Bayesian machine learning techniques to estimate model parameters based upon both prior information and previously collected data, while the inquiry engine implements data-driven exploration. By choosing an experiment whose distribution of expected results has the maximum entropy, the inquiry engine selects the experiment that maximizes the expected information gain. The coupled inference and inquiry engines constitute an autonomous learning method for scientific exploration. We apply it to a robotic arm to demonstrate the efficacy of the method. Optimizing inquiry involves searching for an experiment that promises, on average, to be maximally informative. If the set of potential experiments is described by many parameters, the search involves a high-dimensional entropy space. In such cases, a brute force search method will be slow and computationally expensive. We develop an entropy-based search algorithm, called nested entropy sampling, to select the most informative experiment. This helps to reduce the number of computations necessary to find the optimal experiment. We also extended the method of maximizing entropy, and developed a method of maximizing joint entropy so that it could be used as a principle of collaboration between two robots. This is a major achievement of this thesis, as it allows the information-based collaboration between two robotic units towards a same

  17. Two NASA Dryden F/A-18's land on the Edwards Air Force Base runway after completion of an Autonomous

    Science.gov (United States)

    2001-01-01

    Two NASA Dryden F/A-18's land on the Edwards Air Force Base runway after completion of an Autonomous Formation Flight (AFF) mission. The goal of the AFF project is to demonstrate sustained 10 percent fuel savings by the trailing aircraft during cruise flight. Data suggests savings as high as 15 percent are achievable.

  18. 基于Paparazzi Lisa/M2.0的无人机自主飞行设计%Design of Autonomous Flight for UAV Based on Paparazzi Lisa/M2.0

    Institute of Scientific and Technical Information of China (English)

    王俊明; 曹科才; 肖斌; 汪蓉蓉

    2016-01-01

    The four rotor Unmanned Aerial Vehicle (UAV) is of characteristics such as good movement performance,small size,light weight,novel structure,and friendly environment (not easy to cause damage to the surrounding),and with great value in the military,civ-il and scientific research. Paparazzi is a fully open source project of software and hardware,which began in 2003,aiming to build a strong,autonomous and automatic driving system. In this paper,the Paparazzi Lisa/M 2. 0 and ground control system is introduced first-ly,and then on the basis of the actual production of quad rotor UAV system for analysis of problems that need to be paid attention to in the development process and key steps,and the four rotor UAV is made successfully,and a series of analysis and test are completed. Use of the navigation control of ground control system can make four rotor UAV achieve a series of tasks such as autonomous navigation,hov-ering and landing,detailed study of the design and simulation of path planning control. The simulation shows that the effectiveness and ac-curacy in Paparazzi Lisa/M 2. 0 combined with ground control system for four rotor UAV route planning control,can be used for four ro-tor path planning of UAV command.%四旋翼无人机是一种具有运动性能好、体积小、重量轻、结构新颖、环境友好(相对不易对周围造成伤害)等特点的无人机,在军事、民用及科研方面都具有很大的价值.Paparazzi是一个软硬件全开源的项目,始于2003年,旨在建立一个强大、自主的自动驾驶系统.文中首先介绍了Paparazzi Lisa/M 2.0与地面控制系统,然后在此基础上通过实际制作四旋翼无人机系统,针对分析研发过程中需要注意的问题以及关键步骤,成功制作了四旋翼无人机,并且完成了一系列的分析与测试.利用地面控制系统的导航控制能让四旋翼无人机完成自主导航、悬停和降落等一系列任务,并详细学习了路径规划控制的设

  19. The Route Analysis Based On Flight Plan

    Science.gov (United States)

    Feriyanto, Nur; Saleh, Chairul; Fauzi, Achmad; Rachman Dzakiyullah, Nur; Riza Iwaputra, Kahfi

    2016-02-01

    Economic development effects use of air transportation since the business process in every aspect was increased. Many people these days was prefer using airplane because it can save time and money. This situation also effects flight routes, many airlines offer new routes to deal with competition. Managing flight routes is one of the problems that must be faced in order to find the efficient and effective routes. This paper investigates the best routes based on flight performance by determining the amount of block fuel for the Jakarta-Denpasar flight route. Moreover, in this work compares a two kinds of aircraft and tracks by calculating flight distance, flight time and block fuel. The result shows Jakarta-Denpasar in the Track II has effective and efficient block fuel that can be performed by Airbus 320-200 aircraft. This study can contribute to practice in making an effective decision, especially helping executive management of company due to selecting appropriate aircraft and the track in the flight plan based on the block fuel consumption for business operation.

  20. MEMS-Based Low-Cost Flight Control System for Small UAVs

    Institute of Scientific and Technical Information of China (English)

    FU Xu; ZHOU Zhaoying; XIONG Wei; GUO Qi

    2008-01-01

    Small unmanned air vehicles(UAVs)can be used for vanous kinds of surveillance and data collection missions.The UAV flight control system is the key to a successful mission.This paper describes a low-cost micro-electro mechanical system-based flight control system for small UAVs.The integrated hardware flight control system weighs only 24 g.The system includes a highly-integrated wireless transmission link,which is lighter than traditional links.The flight control provides altitude hold control and global positioning system navigation based on gain scheduling proportional-integral-derivative control.Flight tests to survey the grass quality of a large lawn show that the small UAV can fly autonomously according to a series of pre-arranged waypoints with a controlled altitude while the wireless video system transmits images of the surveillance target to a ground control station.

  1. Effects of Transparency on Pilot Trust and Agreement in the Autonomous Constrained Flight Planner

    Science.gov (United States)

    Sadler, Garrett; Battiste, Henri; Ho, Nhut; Hoffmann, Lauren; Lyons, Joseph; Johnson, Walter; Shively, Robert; Smith, David

    2016-01-01

    We performed a human-in-the-loop study to explore the role of transparency in engendering trust and reliance within highly automated systems. Specifically, we examined how transparency impacts trust in and reliance upon the Autonomous Constrained Flight Planner (ACFP), a critical automated system being developed as part of NASA's Reduced Crew Operations (RCO) Concept. The ACFP is designed to provide an enhanced ground operator, termed a super dispatcher, with recommended diversions for aircraft when their primary destinations are unavailable. In the current study, 12 commercial transport rated pilots who played the role of super dispatchers were given six time-pressured all land scenarios where they needed to use the ACFP to determine diversions for multiple aircraft. Two factors were manipulated. The primary factor was level of transparency. In low transparency scenarios the pilots were given a recommended airport and runway, plus basic information about the weather conditions, the aircraft types, and the airport and runway characteristics at that and other airports. In moderate transparency scenarios the pilots were also given a risk evaluation for the recommended airport, and for the other airports if they requested it. In the high transparency scenario additional information including the reasoning for the risk evaluations was made available to the pilots. The secondary factor was level of risk, either high or low. For high-risk aircraft, all potential diversions were rated as highly risky, with the ACFP giving the best option for a bad situation. For low-risk aircraft the ACFP found only low-risk options for the pilot. Both subjective and objective measures were collected, including rated trust, whether the pilots checked the validity of the automation recommendation, and whether the pilots eventually flew to the recommended diversion airport. Key results show that: 1) Pilots trust increased with higher levels of transparency, 2) Pilots were more likely to

  2. Using Model-Based Reasoning for Autonomous Instrument Operation

    Science.gov (United States)

    Johnson, Mike; Rilee, M.; Truszkowski, W.; Powers, Edward I. (Technical Monitor)

    2000-01-01

    of environmental hazards, frame the problem of constructing autonomous science instruments. we are developing a model of the Low Energy Neutral Atom instrument (LENA) that is currently flying on board the Imager for Magnetosphere-to-Aurora Global Exploration (IMAGE) spacecraft. LENA is a particle detector that uses high voltage electrostatic optics and time-of-flight mass spectrometry to image neutral atom emissions from the denser regions of the Earth's magnetosphere. As with most spacecraft borne science instruments, phenomena in addition to neutral atoms are detected by LENA. Solar radiation and energetic particles from Earth's radiation belts are of particular concern because they may help generate currents that may compromise LENA's long term performance. An explicit model of the instrument response has been constructed and is currently in use on board IMAGE to dynamically adapt LENA to the presence or absence of energetic background radiations. The components of LENA are common in space science instrumentation, and lessons learned by modelling this system may be applied to other instruments. This work demonstrates that a model-based approach can be used to enhance science instrument effectiveness. Our future work involves the extension of these methods to cover more aspects of LENA operation and the generalization to other space science instrumentation.

  3. 3D Vision Based Landing Control of a Small Scale Autonomous Helicopter

    Directory of Open Access Journals (Sweden)

    Zhenyu Yu

    2008-11-01

    Full Text Available Autonomous landing is a challenging but important task for Unmanned Aerial Vehicles (UAV to achieve high level of autonomy. The fundamental requirement for landing is the knowledge of the height above the ground, and a properly designed controller to govern the process. This paper presents our research results in the study of landing an autonomous helicopter. The abovetheground height sensing is based on a 3D vision system. We have designed a simple planefitting method for estimating the height over the ground. The method enables vibration free measurement with the camera rigidly attached on the helicopter without using complicated gimbal or active vision mechanism. The estimated height is used by the landing control loop. Considering the ground effect during landing, we have proposed a twostage landing procedure. Two controllers are designed for the two landing stages respectively. The sensing approach and control strategy has been verified in field flight test and has demonstrated satisfactory performance.

  4. Quad-Rotor Helicopter Autonomous Navigation Based on Vanishing Point Algorithm

    Directory of Open Access Journals (Sweden)

    Jialiang Wang

    2014-01-01

    Full Text Available Quad-rotor helicopter is becoming popular increasingly as they can well implement many flight missions in more challenging environments, with lower risk of damaging itself and its surroundings. They are employed in many applications, from military operations to civilian tasks. Quad-rotor helicopter autonomous navigation based on the vanishing point fast estimation (VPFE algorithm using clustering principle is implemented in this paper. For images collected by the camera of quad-rotor helicopter, the system executes the process of preprocessing of image, deleting noise interference, edge extracting using Canny operator, and extracting straight lines by randomized hough transformation (RHT method. Then system obtains the position of vanishing point and regards it as destination point and finally controls the autonomous navigation of the quad-rotor helicopter by continuous modification according to the calculated navigation error. The experimental results show that the quad-rotor helicopter can implement the destination navigation well in the indoor environment.

  5. Autonomous Operations Planner: A Flexible Platform for Research in Flight-Deck Support for Airborne Self-Separation

    Science.gov (United States)

    Karr, David A.; Vivona, Robert A.; DePascale, Stephen M.; Wing, David J.

    2012-01-01

    The Autonomous Operations Planner (AOP), developed by NASA, is a flexible and powerful prototype of a flight-deck automation system to support self-separation of aircraft. The AOP incorporates a variety of algorithms to detect and resolve conflicts between the trajectories of its own aircraft and traffic aircraft while meeting route constraints such as required times of arrival and avoiding airspace hazards such as convective weather and restricted airspace. This integrated suite of algorithms provides flight crew support for strategic and tactical conflict resolutions and conflict-free trajectory planning while en route. The AOP has supported an extensive set of experiments covering various conditions and variations on the self-separation concept, yielding insight into the system s design and resolving various challenges encountered in the exploration of the concept. The design of the AOP will enable it to continue to evolve and support experimentation as the self-separation concept is refined.

  6. On Cognitive Style in English Web-based Autonomous Learning

    Institute of Scientific and Technical Information of China (English)

    刘茜

    2014-01-01

    Since Henry Holec first put forward the term‘Autonomy’in 1980’s, autonomous learning has been drawing the uni⁃versal attention of scholars both at home and abroad. Promoting learners’ability of self-regulated learning has been taken as one of the important goals of modern education. College English autonomous learning based on network environment does not mean free study without any restraints or monitoring, but rather involves the self-monitoring and external monitoring. Meanwhile, dif⁃ferent learners may have different cognitive styles in their learning processes, which may have an influence on the improvement of the learners’efficiency in the autonomous language learning. Proper monitoring models coordinating with the students ’differ⁃ent field cognitive styles.

  7. Timeline based autonomous mission planning system for deep space exploration

    Institute of Scientific and Technical Information of China (English)

    徐瑞; 崔平远; 徐晓飞; 崔祜涛; 栾恩杰

    2004-01-01

    In order to realize the explorer autonomy, the software architecture of autonomous mission management system (AMMS) is given for the deep space explorer, and the autonomous mission planning system, the kernel part of this architecture, is designed in detail. In order to describe the parallel activity, the state timeline is introduced to build the formal model of the planning system and based on this model, the temporal constraint satisfaction planning algorithm is proposed to produce the explorer's activity sequence. With some key subsystems of the deep space explorer as examples, the autonomous mission planning simulation system is designed.The results show that this system can calculate the executable activity sequence with the given mission goals and initial state of the explorer.

  8. Ant Colony Based Path Planning Algorithm for Autonomous Robotic Vehicles

    Directory of Open Access Journals (Sweden)

    Yogita Gigras

    2012-11-01

    Full Text Available The requirement of an autonomous robotic vehicles demand highly efficient algorithm as well as software. Today’s advanced computer hardware technology does not provide these types of extensive processing capabilities, so there is still a major space and time limitation for the technologies that are available for autonomous robotic applications. Now days, small to miniature mobile robots are required for investigation, surveillance and hazardous material detection for military and industrial applications. But these small sized robots have limited power capacity as well as memory and processing resources. A number of algorithms exist for producing optimal path for dynamically cost. This paper presents a new ant colony based approach which is helpful in solving path planning problem for autonomous robotic application. The experiment of simulation verified its validity of algorithm in terms of time.

  9. 3D flash lidar performance in flight testing on the Morpheus autonomous, rocket-propelled lander to a lunar-like hazard field

    Science.gov (United States)

    Roback, Vincent E.; Amzajerdian, Farzin; Bulyshev, Alexander E.; Brewster, Paul F.; Barnes, Bruce W.

    2016-05-01

    For the first time, a 3-D imaging Flash Lidar instrument has been used in flight to scan a lunar-like hazard field, build a 3-D Digital Elevation Map (DEM), identify a safe landing site, and, in concert with an experimental Guidance, Navigation, and Control system, help to guide the Morpheus autonomous, rocket-propelled, free-flying lander to that safe site on the hazard field. The flight tests served as the TRL 6 demo of the Autonomous Precision Landing and Hazard Detection and Avoidance Technology (ALHAT) system and included launch from NASA-Kennedy, a lunar-like descent trajectory from an altitude of 250m, and landing on a lunar-like hazard field of rocks, craters, hazardous slopes, and safe sites 400m down-range. The ALHAT project developed a system capable of enabling safe, precise crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The Flash Lidar is a second generation, compact, real-time, air-cooled instrument. Based upon extensive on-ground characterization at flight ranges, the Flash Lidar was shown to be capable of imaging hazards from a slant range of 1 km with an 8 cm range precision and a range accuracy better than 35 cm, both at 1-σ. The Flash Lidar identified landing hazards as small as 30 cm from the maximum slant range which Morpheus could achieve (450 m); however, under certain wind conditions it was susceptible to scintillation arising from air heated by the rocket engine and to pre-triggering on a dust cloud created during launch and transported down-range by wind.

  10. 3-D Flash Lidar Performance in Flight Testing on the Morpheus Autonomous, Rocket-Propelled Lander to a Lunar-Like Hazard Field

    Science.gov (United States)

    Roback, Vincent E.; Amzajerdian, Farzin; Bulyshev, Alexander E.; Brewster, Paul F.; Barnes, Bruce W.

    2016-01-01

    For the first time, a 3-D imaging Flash Lidar instrument has been used in flight to scan a lunar-like hazard field, build a 3-D Digital Elevation Map (DEM), identify a safe landing site, and, in concert with an experimental Guidance, Navigation, and Control (GN&C) system, help to guide the Morpheus autonomous, rocket-propelled, free-flying lander to that safe site on the hazard field. The flight tests served as the TRL 6 demo of the Autonomous Precision Landing and Hazard Detection and Avoidance Technology (ALHAT) system and included launch from NASA-Kennedy, a lunar-like descent trajectory from an altitude of 250m, and landing on a lunar-like hazard field of rocks, craters, hazardous slopes, and safe sites 400m down-range. The ALHAT project developed a system capable of enabling safe, precise crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The Flash Lidar is a second generation, compact, real-time, air-cooled instrument. Based upon extensive on-ground characterization at flight ranges, the Flash Lidar was shown to be capable of imaging hazards from a slant range of 1 km with an 8 cm range precision and a range accuracy better than 35 cm, both at 1-delta. The Flash Lidar identified landing hazards as small as 30 cm from the maximum slant range which Morpheus could achieve (450 m); however, under certain wind conditions it was susceptible to scintillation arising from air heated by the rocket engine and to pre-triggering on a dust cloud created during launch and transported down-range by wind.

  11. Vision Based Autonomous Robot Navigation Algorithms and Implementations

    CERN Document Server

    Chatterjee, Amitava; Nirmal Singh, N

    2013-01-01

    This book is devoted to the theory and development of autonomous navigation of mobile robots using computer vision based sensing mechanism. The conventional robot navigation systems, utilizing traditional sensors like ultrasonic, IR, GPS, laser sensors etc., suffer several drawbacks related to either the physical limitations of the sensor or incur high cost. Vision sensing has emerged as a popular alternative where cameras can be used to reduce the overall cost, maintaining high degree of intelligence, flexibility and robustness. This book includes a detailed description of several new approaches for real life vision based autonomous navigation algorithms and SLAM. It presents the concept of how subgoal based goal-driven navigation can be carried out using vision sensing. The development concept of vision based robots for path/line tracking using fuzzy logic is presented, as well as how a low-cost robot can be indigenously developed in the laboratory with microcontroller based sensor systems. The book descri...

  12. Autonomous Navigation for Autonomous Underwater Vehicles Based on Information Filters and Active Sensing

    Directory of Open Access Journals (Sweden)

    Tianhong Yan

    2011-11-01

    Full Text Available This paper addresses an autonomous navigation method for the autonomous underwater vehicle (AUV C-Ranger applying information-filter-based simultaneous localization and mapping (SLAM, and its sea trial experiments in Tuandao Bay (Shangdong Province, P.R. China. Weak links in the information matrix in an extended information filter (EIF can be pruned to achieve an efficient approach-sparse EIF algorithm (SEIF-SLAM. All the basic update formulae can be implemented in constant time irrespective of the size of the map; hence the computational complexity is significantly reduced. The mechanical scanning imaging sonar is chosen as the active sensing device for the underwater vehicle, and a compensation method based on feedback of the AUV pose is presented to overcome distortion of the acoustic images due to the vehicle motion. In order to verify the feasibility of the navigation methods proposed for the C-Ranger, a sea trial was conducted in Tuandao Bay. Experimental results and analysis show that the proposed navigation approach based on SEIF-SLAM improves the accuracy of the navigation compared with conventional method; moreover the algorithm has a low computational cost when compared with EKF-SLAM.

  13. Autonomous navigation for autonomous underwater vehicles based on information filters and active sensing.

    Science.gov (United States)

    He, Bo; Zhang, Hongjin; Li, Chao; Zhang, Shujing; Liang, Yan; Yan, Tianhong

    2011-01-01

    This paper addresses an autonomous navigation method for the autonomous underwater vehicle (AUV) C-Ranger applying information-filter-based simultaneous localization and mapping (SLAM), and its sea trial experiments in Tuandao Bay (Shangdong Province, P.R. China). Weak links in the information matrix in an extended information filter (EIF) can be pruned to achieve an efficient approach-sparse EIF algorithm (SEIF-SLAM). All the basic update formulae can be implemented in constant time irrespective of the size of the map; hence the computational complexity is significantly reduced. The mechanical scanning imaging sonar is chosen as the active sensing device for the underwater vehicle, and a compensation method based on feedback of the AUV pose is presented to overcome distortion of the acoustic images due to the vehicle motion. In order to verify the feasibility of the navigation methods proposed for the C-Ranger, a sea trial was conducted in Tuandao Bay. Experimental results and analysis show that the proposed navigation approach based on SEIF-SLAM improves the accuracy of the navigation compared with conventional method; moreover the algorithm has a low computational cost when compared with EKF-SLAM.

  14. Flight Mechanics/Estimation Theory Symposium. [with application to autonomous navigation and attitude/orbit determination

    Science.gov (United States)

    Fuchs, A. J. (Editor)

    1979-01-01

    Onboard and real time image processing to enhance geometric correction of the data is discussed with application to autonomous navigation and attitude and orbit determination. Specific topics covered include: (1) LANDSAT landmark data; (2) star sensing and pattern recognition; (3) filtering algorithms for Global Positioning System; and (4) determining orbital elements for geostationary satellites.

  15. Design and Implementation of Autonomous Sonar Based Vehicle Robot

    Directory of Open Access Journals (Sweden)

    Muhammad Adil Ansari

    2011-07-01

    Full Text Available Autonomous robots are intelligent machines that are capable of performing desired tasks by themselves, without explicit human control. This paper presents design and implementation of the ASVR (Autonomous Sonar Based Vehicle Robot. ASVR is a microcontroller based, programmable mobile robot that can sense and react to its environment and can work in partially known and unpredictable environments. A novel algorithm based on ultrasonic sensors and simple calculations for real-time obstacle detection and avoidance that is intended for mobile robots is also outlined. Also a novel technique is proposed and implemented for steering referencing of vehicle. The design is implemented in air using ultrasonic sensors but can be adapted using sonar to underwater environments where it has important applications such as deep sea maintenance and reconnaissance tasks. The paper also presents performance results of a prototype developed to prove the design concept.

  16. Biological Inspired Direct Adaptive Guidance and Control for Autonomous Flight Systems

    Science.gov (United States)

    2007-11-02

    improvements for existing algorithms. " Continue the phase I effort to develop and demonstrate an architecture for direct adaptive guidance including...e.g., 1 x I x 2 cm) autonomous, cooperative agents from the point of view of power (e.g., 1 mW for a year), bionics , and navigation/guidance. Although...guidance solution (such as PN) to correct for evasive target maneuvering. One such architecture that appears to be suitable for surmounting this difficulty

  17. Autonomous Spacecraft Navigation Based on Pulsar Timing Information

    CERN Document Server

    Bernhardt, Mike Georg; Prinz, Tobias; Breithuth, Ferdinand Maximilian; Walter, Ulrich

    2011-01-01

    We discuss the possibility of an autonomous navigation system for spacecraft that is based on pulsar timing data. Pulsars are rapidly rotating neutron stars that are observable as variable celestial sources of electromagnetic radiation. Their periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board the spacecraft with predicted pulse arrivals at some reference location, the spacecraft position can be determined autonomously with accuracies on the order of 5 kilometres. For a spacecraft at a distance of 10 astronomical units from Earth (e.g., Earth-Saturn), this means an improvement by a factor of 8 compared to conventional methods. Therefore this new technology is an alternative to standard navigation based on radio tracking by ground stations, without the disadvantages of uncertainty in...

  18. Omnivision-based autonomous mobile robotic platform

    Science.gov (United States)

    Cao, Zuoliang; Hu, Jun; Cao, Jin; Hall, Ernest L.

    2001-10-01

    As a laboratory demonstration platform, TUT-I mobile robot provides various experimentation modules to demonstrate the robotics technologies that are involved in remote control, computer programming, teach-and-playback operations. Typically, the teach-and-playback operation has been proved to be an effective solution especially in structured environments. The path generated in the teach mode and path correction in real-time using path error detecting in the playback mode are demonstrated. The vision-based image database is generated as the given path representation in the teaching procedure. The algorithm of an online image positioning is performed for path following. Advanced sensory capability is employed to provide environment perception. A unique omni directional vision (omni-vision) system is used for localization and navigation. The omni directional vision involves an extremely wide-angle lens, which has the feature that a dynamic omni-vision image is processed in real time to respond the widest view during the movement. The beacon guidance is realized by observing locations of points derived from over-head features such as predefined light arrays in a building. The navigation approach is based upon the omni-vision characteristics. A group of ultrasonic sensors is employed for obstacle avoidance.

  19. SAMURAI: Polar AUV-Based Autonomous Dexterous Sampling

    Science.gov (United States)

    Akin, D. L.; Roberts, B. J.; Smith, W.; Roderick, S.; Reves-Sohn, R.; Singh, H.

    2006-12-01

    While autonomous undersea vehicles are increasingly being used for surveying and mapping missions, as of yet there has been little concerted effort to create a system capable of performing physical sampling or other manipulation of the local environment. This type of activity has typically been performed under teleoperated control from ROVs, which provides high-bandwidth real-time human direction of the manipulation activities. Manipulation from an AUV will require a completely autonomous sampling system, which implies both advanced technologies such as machine vision and autonomous target designation, but also dexterous robot manipulators to perform the actual sampling without human intervention. As part of the NASA Astrobiology Science and Technology for Exploring the Planets (ASTEP) program, the University of Maryland Space Systems Laboratory has been adapting and extending robotics technologies developed for spacecraft assembly and maintenance to the problem of autonomous sampling of biologicals and soil samples around hydrothermal vents. The Sub-polar ice Advanced Manipulator for Universal Sampling and Autonomous Intervention (SAMURAI) system is comprised of a 6000-meter capable six-degree-of-freedom dexterous manipulator, along with an autonomous vision system, multi-level control system, and sampling end effectors and storage mechanisms to allow collection of samples from vent fields. SAMURAI will be integrated onto the Woods Hole Oceanographic Institute (WHOI) Jaguar AUV, and used in Arctic during the fall of 2007 for autonomous vent field sampling on the Gakkel Ridge. Under the current operations concept, the JAGUAR and PUMA AUVs will survey the water column and localize on hydrothermal vents. Early mapping missions will create photomosaics of the vents and local surroundings, allowing scientists on the mission to designate desirable sampling targets. Based on physical characteristics such as size, shape, and coloration, the targets will be loaded into the

  20. Autonomous planning system based on temporal constraint satisfaction

    Institute of Scientific and Technical Information of China (English)

    徐瑞; 崔平远; 徐晓飞; 吴伟仁; 田玉龙

    2003-01-01

    In order to realize spacecraft autonomy activity duration and complex temporal relations must betaken into consideration. In the space mission planning system, the traditional planners are unable to describethis knowledge, so an object-oriented temporal knowledge representation method is proposed to model every ac-tivity as an object to describe the activity' s duration, start-time, end-time and the temporal relations with otheractivities. The layered planming agent architecture is then designed for spacecraft autonomous operation, and thefunctions of every component are given. A planning algorithm based on the temporal constraint satisfaction isbuilt in detail using this knowledge representation and system architecture. The prototype of Deep Space MissionAutonomous Planning System is implemented. The results show that with the object-oriented temporal knowledgedescription method, the space mission planning system can be used to describe simultaneous activities, resourceand temporal constraints, and produce a complete plan for exploration mission quickly under complex con-straints.

  1. Autonomous Traffic Control System Using Agent Based Technology

    CERN Document Server

    M, Venkatesh; V, Srinivas

    2011-01-01

    The way of analyzing, designing and building of real-time projects has been changed due to the rapid growth of internet, mobile technologies and intelligent applications. Most of these applications are intelligent, tiny and distributed components called as agent. Agent works like it takes the input from numerous real-time sources and gives back the real-time response. In this paper how these agents can be implemented in vehicle traffic management especially in large cities and identifying various challenges when there is a rapid growth of population and vehicles. In this paper our proposal gives a solution for using autonomous or agent based technology. These autonomous or intelligent agents have the capability to observe, act and learn from their past experience. This system uses the knowledge flow of precedent signal or data to identify the incoming flow of forthcoming signal. Our architecture involves the video analysis and exploration using some Intelligence learning algorithm to estimate and identify the...

  2. Use of In-Flight Data to Validate Mars Samle Return Autonomous RvD GNC

    DEFF Research Database (Denmark)

    Barrena, V.; Colmenarejo, P.; Suatoni, M.

    During the last years, the number of studies having as objective rendezvous and docking/capture missions around Mars or other planets/asteroids has significantly increased. Following this tendency, a team led by GMV has developed HARvD (High Integrity Autonomous Rendezvous Docking Control System...... that in this approach the on-board SW does not require modification. Such modifications are costly and complex. Therefore the results of the HARvD system validation can be maximized with respect to the involved effort. This paper presents the experiment definition and development of the HARvD-PRISMA experiment...

  3. Development of Autonomous Unmanned Aerial Vehicle Platform: Modeling, Simulating, and Flight Testing

    Science.gov (United States)

    2006-03-01

    Shin-Ichiro Higashino of the Universities of Washington, Seattle, and Kyushu, Japan respectively. In 2003, Ly and Higashino conducted research similar...of Technology, MA. September 2004. Ly, L. and Higashino , S. “Development of a UAV-Flight Test Vehicle at the University of Washington.” Presented

  4. Toward autonomous rotorcraft flight in degraded visual environments: experiments and lessons learned

    Science.gov (United States)

    Stambler, Adam; Spiker, Spencer; Bergerman, Marcel; Singh, Sanjiv

    2016-05-01

    Unmanned cargo delivery to combat outposts will inevitably involve operations in degraded visual environments (DVE). When DVE occurs, the aircraft autonomy system needs to be able to function regardless of the obscurant level. In 2014, Near Earth Autonomy established a baseline perception system for autonomous rotorcraft operating in clear air conditions, when its m3 sensor suite and perception software enabled autonomous, no-hover landings onto unprepared sites populated with obstacles. The m3's long-range lidar scanned the helicopter's path and the perception software detected obstacles and found safe locations for the helicopter to land. This paper presents the results of initial tests with the Near Earth perception system in a variety of DVE conditions and analyzes them from the perspective of mission performance and risk. Tests were conducted with the m3's lidar and a lightweight synthetic aperture radar in rain, smoke, snow, and controlled brownout experiments. These experiments showed the capability to penetrate through mild DVE but the perceptual capabilities became degraded with the densest brownouts. The results highlight the need for not only improved ability to see through DVE, but also for improved algorithms to monitor and report DVE conditions.

  5. Assembly of an Experimental Quad-Rotor Type UAV for Testing a Novel Autonomous Flight Control Strategy

    Directory of Open Access Journals (Sweden)

    Shahida Khatoon

    2013-12-01

    Full Text Available In this research a prototype experimental Quad-rotor type UAV have been assembled using low cost components easily available in the Indian market. The quad-copter is used for testing a novel autonomous flight control strategy developed using embedded system. In order to enable a mini-UAV to perform target acquisition, localization and continuous surveillance in real world environment one must develop a technology which may be a combination of aircraft engineering, control systems, and wireless communication. The major limiting factors in developing the capabilities of small low cost UAVs are connectivity, computational processing power and lack of resource integration. To overcome these limitations in this research we have tried to assemble an experimental quad-rotor prototype UAV capable of being remotely controlled in the range of 20 meter, which is specifically designed as an economical, moderately functional, small airborne platform intended to meet the requirement for fast-response to time-critical events in many small private sectors or government agencies. The experimental prototype quad-copter has been successfully implemented and tested for 15 minutes smooth flight time.

  6. Autonomous Navigation of Small Uavs Based on Vehicle Dynamic Model

    Science.gov (United States)

    Khaghani, M.; Skaloud, J.

    2016-03-01

    This paper presents a novel approach to autonomous navigation for small UAVs, in which the vehicle dynamic model (VDM) serves as the main process model within the navigation filter. The proposed method significantly increases the accuracy and reliability of autonomous navigation, especially for small UAVs with low-cost IMUs on-board. This is achieved with no extra sensor added to the conventional INS/GNSS setup. This improvement is of special interest in case of GNSS outages, where inertial coasting drifts very quickly. In the proposed architecture, the solution to VDM equations provides the estimate of position, velocity, and attitude, which is updated within the navigation filter based on available observations, such as IMU data or GNSS measurements. The VDM is also fed with the control input to the UAV, which is available within the control/autopilot system. The filter is capable of estimating wind velocity and dynamic model parameters, in addition to navigation states and IMU sensor errors. Monte Carlo simulations reveal major improvements in navigation accuracy compared to conventional INS/GNSS navigation system during the autonomous phase, when satellite signals are not available due to physical obstruction or electromagnetic interference for example. In case of GNSS outages of a few minutes, position and attitude accuracy experiences improvements of orders of magnitude compared to inertial coasting. It means that during such scenario, the position-velocity-attitude (PVA) determination is sufficiently accurate to navigate the UAV to a home position without any signal that depends on vehicle environment.

  7. Guidance and Control of an Autonomous Soaring Vehicle with Flight Test Results

    Science.gov (United States)

    Allen, Michael J.

    2007-01-01

    A guidance and control method was developed to detect and exploit thermals for energy gain. Latency in energy rate estimation degraded performance. The concept of a UAV harvesting energy from the atmosphere has been shown to be feasible with existing technology. Many UAVs have similar mission constraints to birds and sailplanes. a) Surveillance; b) Point to point flight with minimal energy; and c) Increased ground speed.

  8. Flight Control Design for an Autonomous Rotorcraft Using Pseudo-Sliding Mode Control and Waypoint Navigation

    Science.gov (United States)

    Mallory, Nicolas Joseph

    The design of robust automated flight control systems for aircraft of varying size and complexity is a topic of continuing interest for both military and civilian industries. By merging the benefits of robustness from sliding mode control (SMC) with the familiarity and transparency of design tradeoff offered by frequency domain approaches, this thesis presents pseudo-sliding mode control as a viable option for designing automated flight control systems for complex six degree-of-freedom aircraft. The infinite frequency control switching of SMC is replaced, by necessity, with control inputs that are continuous in nature. An introduction to SMC theory is presented, followed by a detailed design of a pseudo-sliding mode control and automated flight control system for a six degree-of-freedom model of a Hughes OH6 helicopter. This model is then controlled through three different waypoint missions that demonstrate the stability of the system and the aircraft's ability to follow certain maneuvers despite time delays, large changes in model parameters and vehicle dynamics, actuator dynamics, sensor noise, and atmospheric disturbances.

  9. Agent Based Approaches to Engineering Autonomous Space Software

    CERN Document Server

    Dennis, Louise A; Lincoln, Nicholas; Lisitsa, Alexei; Veres, Sandor M

    2010-01-01

    Current approaches to the engineering of space software such as satellite control systems are based around the development of feedback controllers using packages such as MatLab's Simulink toolbox. These provide powerful tools for engineering real time systems that adapt to changes in the environment but are limited when the controller itself needs to be adapted. We are investigating ways in which ideas from temporal logics and agent programming can be integrated with the use of such control systems to provide a more powerful layer of autonomous decision making. This paper will discuss our initial approaches to the engineering of such systems.

  10. Study on autonomous navigation based on pulsar timing model

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The basic principle of pulsar timing model was introduced, and the general relativistic corrections were analyzed when pulse time of arrival (TOA) was transferred to coordinate TOA at the Solar System Barycentre. Based on the shifting, an iterative method of autonomous position determination for spacecraft was developed. Accordingly, the linear form of the position offset equation was evolved. Using the initial estimated value of spacecraft’s position as the input of pulsar timing equation, through calculation of the offset between measured or transferred and predicted TOA, the position offset can be solved by Least Squares. At last, the main error sources including modeling error and parameters error were discussed.

  11. Study on autonomous navigation based on pulsar timing model

    Institute of Scientific and Technical Information of China (English)

    LI JianXun; KE XiZheng

    2009-01-01

    The basic principle of pulsar timing model was introduced, and the general relativistic corrections were analyzed when pulse time of arrival (TOA) was transferred to coordinate TOA at the Solar System Barycentre. Based on the shifting, an iterative method of autonomous position determination for spacecraft was developed. Accordingly, the linear form of the position offset equation was evolved. Using the initial estimated value of spacecraft's position as the input of pulsar timing equation, through calculation of the offset between measured or transferred and predicted TOA, the position offset can be solved by Least Squares. At last, the main error sources including modeling error and parameters error were discussed.

  12. Optic flow-based vision system for autonomous 3D localization and control of small aerial vehicles

    OpenAIRE

    Kendoul, Farid; Fantoni, Isabelle; Nonami, Kenzo

    2009-01-01

    International audience; The problem considered in this paper involves the design of a vision-based autopilot for small and micro Unmanned Aerial Vehicles (UAVs). The proposed autopilot is based on an optic flow-based vision system for autonomous localization and scene mapping, and a nonlinear control system for flight control and guidance. This paper focusses on the development of a real-time 3D vision algorithm for estimating optic flow, aircraft self-motion and depth map, using a low-resolu...

  13. A Vision-Based Relative Navigation Approach for Autonomous Multirotor Aircraft

    Science.gov (United States)

    Leishman, Robert C.

    Autonomous flight in unstructured, confined, and unknown GPS-denied environments is a challenging problem. Solutions could be tremendously beneficial for scenarios that require information about areas that are difficult to access and that present a great amount of risk. The goal of this research is to develop a new framework that enables improved solutions to this problem and to validate the approach with experiments using a hardware prototype. In Chapter 2 we examine the consequences and practical aspects of using an improved dynamic model for multirotor state estimation, using only IMU measurements. The improved model correctly explains the measurements available from the accelerometers on a multirotor. We provide hardware results demonstrating the improved attitude, velocity and even position estimates that can be achieved through the use of this model. We propose a new architecture to simplify some of the challenges that constrain GPS-denied aerial flight in Chapter 3. At the core, the approach combines visual graph-SLAM with a multiplicative extended Kalman filter (MEKF). More importantly, we depart from the common practice of estimating global states and instead keep the position and yaw states of the MEKF relative to the current node in the map. This relative navigation approach provides a tremendous benefit compared to maintaining estimates with respect to a single global coordinate frame. We discuss the architecture of this new system and provide important details for each component. We verify the approach with goal-directed autonomous flight-test results. The MEKF is the basis of the new relative navigation approach and is detailed in Chapter 4. We derive the relative filter and show how the states must be augmented and marginalized each time a new node is declared. The relative estimation approach is verified using hardware flight test results accompanied by comparisons to motion capture truth. Additionally, flight results with estimates in the control

  14. Movable Ground Based Recovery System for Reuseable Space Flight Hardware

    Science.gov (United States)

    Sarver, George L. (Inventor)

    2013-01-01

    A reusable space flight launch system is configured to eliminate complex descent and landing systems from the space flight hardware and move them to maneuverable ground based systems. Precision landing of the reusable space flight hardware is enabled using a simple, light weight aerodynamic device on board the flight hardware such as a parachute, and one or more translating ground based vehicles such as a hovercraft that include active speed, orientation and directional control. The ground based vehicle maneuvers itself into position beneath the descending flight hardware, matching its speed and direction and captures the flight hardware. The ground based vehicle will contain propulsion, command and GN&C functionality as well as space flight hardware landing cushioning and retaining hardware. The ground based vehicle propulsion system enables longitudinal and transverse maneuverability independent of its physical heading.

  15. In-Flight Fault Diagnosis for Autonomous Aircraft Via Low-Rate Telemetry Channel

    DEFF Research Database (Denmark)

    Blanke, Mogens; Hansen, Søren

    2012-01-01

    An in-flight diagnosis system that is able to detect faults on an unmanned aircraft using real-time telemetry data could provide operator assistance to warn about imminent risks due to faults. However, limited bandwidth of the air-ground radio-link makes diagnosis difficult. Loss of information...... about rapid dynamic changes and high parameter uncertainty are the main difficulties. This paper explores time-domain relations in received telemetry signals and uses knowledge of aircraft dynamics and the mechanics behind physical faults to obtain a set of greybox models for diagnosis. Relating...... actuator fin deflections with angular rates of the aircraft, low order models are derived and parameters are estimated using system identification techniques. Change detection methods are applied to the prediction error of angular rate estimates and properties of the test statistics are determined...

  16. Adaptive Fuzzy Knowledge Based Controller for Autonomous Robot Motion Control

    Directory of Open Access Journals (Sweden)

    Mbaitiga Zacharie

    2010-01-01

    Full Text Available Problem statement: Research into robot motion control offers research opportunities that will change scientists and engineers for year to come. Autonomous robots are increasingly evident in many aspects of industry and everyday life and a robust robot motion control can be used for homeland security and many consumer applications. This study discussed the adaptive fuzzy knowledge based controller for robot motion control in indoor and outdoor environment. Approach: The proposed method consisted of two components: the process monitor that detects changes in the process characteristics and the adaptation mechanism that used information passed to it by the process monitor to update the controller parameters. Results: Experimental evaluation had been done in both indoor and outdoor environment where the robot communicates with the base station through its Wireless fidelity antenna and the performance monitor used a set of five performance criteria to access the fuzzy knowledge based controller. Conclusion: The proposed method had been found to be robust.

  17. 3D Vision Based Landing Control of a Small Scale Autonomous Helicopter

    Directory of Open Access Journals (Sweden)

    Zhenyu Yu

    2007-03-01

    Full Text Available Autonomous landing is a challenging but important task for Unmanned Aerial Vehicles (UAV to achieve high level of autonomy. The fundamental requirement for landing is the knowledge of the height above the ground, and a properly designed controller to govern the process. This paper presents our research results in the study of landing an autonomous helicopter. The above-the-ground height sensing is based on a 3D vision system. We have designed a simple plane-fitting method for estimating the height over the ground. The method enables vibration free measurement with the camera rigidly attached on the helicopter without using complicated gimbal or active vision mechanism. The estimated height is used by the landing control loop. Considering the ground effect during landing, we have proposed a two-stage landing procedure. Two controllers are designed for the two landing stages respectively. The sensing approach and control strategy has been verified in field flight test and has demonstrated satisfactory performance.

  18. Control design for an autonomous wind based hydrogen production system

    Energy Technology Data Exchange (ETDEWEB)

    Valenciaga, F.; Evangelista, C.A. [CONICET, Laboratorio de Electronica Industrial Control e Instrumentacion (LEICI), Facultad de Ingenieria, Universidad Nacional de La Plata, CC.91, C.P. 1900, La Plata (Argentina)

    2010-06-15

    This paper presents a complete control scheme to efficiently manage the operation of an autonomous wind based hydrogen production system. This system comprises a wind energy generation module based on a multipolar permanent magnet synchronous generator, a lead-acid battery bank as short term energy storage and an alkaline von Hoerner electrolyzer. The control is developed in two hierarchical levels. The higher control level or supervisor control determines the general operation strategy for the whole system according to the wind conditions and the state of charge of the battery bank. On the other hand, the lower control level includes the individual controllers that regulate the respective module operation assuming the set-points determined by the supervisor control. These last controllers are approached using second-order super-twisting sliding mode techniques. The performance of the closed-loop system is assessed through representative computer simulations. (author)

  19. Hair-based sensors for micro-autonomous systems

    Science.gov (United States)

    Sadeghi, Mahdi M.; Peterson, Rebecca L.; Najafi, Khalil

    2012-06-01

    We seek to harness microelectromechanical systems (MEMS) technologies to build biomimetic devices for low-power, high-performance, robust sensors and actuators on micro-autonomous robot platforms. Hair is used abundantly in nature for a variety of functions including balance and inertial sensing, flow sensing and aerodynamic (air foil) control, tactile and touch sensing, insulation and temperature control, particle filtering, and gas/chemical sensing. Biological hairs, which are typically characterized by large surface/volume ratios and mechanical amplification of movement, can be distributed in large numbers over large areas providing unprecedented sensitivity, redundancy, and stability (robustness). Local neural transduction allows for space- and power-efficient signal processing. Moreover by varying the hair structure and transduction mechanism, the basic hair form can be used for a wide diversity of functions. In this paper, by exploiting a novel wafer-level, bubble-free liquid encapsulation technology, we make arrays of micro-hydraulic cells capable of electrostatic actuation and hydraulic amplification, which enables high force/high deflection actuation and extremely sensitive detection (sensing) at low power. By attachment of cilia (hair) to the micro-hydraulic cell, air flow sensors with excellent sensitivity ( 10 m/s) have been built. A second-generation design has significantly reduced the sensor response time while maintaining sensitivity of about 2 cm/s and dynamic range of more than 15 m/s. These sensors can be used for dynamic flight control of flying robots or for situational awareness in surveillance applications. The core biomimetic technologies developed are applicable to a broad range of sensors and actuators.

  20. Design of energy-based terrain following flight control system

    Science.gov (United States)

    Wang, Wei; Li, Aijun; Xie, Yanwu; Tan, Jian

    2006-11-01

    Historically, aircraft longitudinal control has been realized by means of two loops: flight path (the control variable is elevator displacement) and speed control (the control variable is propulsive thrust or engine power). Both the elevator and throttle control cause coupled altitude and speed response, which exerts negative effects on longitudinal flight performance of aircraft, especially for Terrain Following(TF) flight. Energy-based method can resolve coupled problem between flight speed and path by controlling total energy rate and energy distribution rate between elevator and throttle. In this paper, energy-based control method is applied to design a TF flight control system for controlling flight altitude directly. An error control method of airspeed and altitude is adopted to eliminate the stable error of the total energy control system when decoupling control. Pitch loop and pitch rate feedback loop are designed for the system to damp the oscillatory response produced by TF system. The TF flight control system structure diagram and an aircraft point-mass energy motion model including basic control loops are given and used to simulate decoupling performance of the TF fight control system. Simulation results show that the energy-based TF flight control system can decouple flight velocity and flight path angle, exactly follow planned flight path, and greatly reduce altitude error, which is between +10m and -8m.

  1. Landmark-based autonomous navigation for pinpoint planetary landing

    Science.gov (United States)

    Xu, Chao; Wang, Dayi; Huang, Xiangyu

    2016-12-01

    A landmark-based autonomous navigation scheme is presented for pinpoint planetary landing. The dynamic model is built on the basis of measurements from Inertial Measurement Unit. Measurement models of landmarks with known coordinates and landmarks with unknown coordinates extracted from sequential descent images are developed and used to calculated the state corrections in Extend Kalman Filter, respectively. Then, the corrections are fused by a covariance intersection fusion algorithm to perform state updates. The tight coupling of the two types of landmark observations yields accurate and robust state estimates. Extensive simulations are performed, which confirm the validity of the proposed navigation scheme and analyze the effects of factors, such as the horizonal position errors and the densities of landmarks with known coordinates and the roughness of the landing surface, on the navigation accuracy.

  2. Autonomous Navigation of Mobile Robot Based on Flood Fill Algorithm

    Directory of Open Access Journals (Sweden)

    Ayad Mohammed Jabbar

    2016-06-01

    Full Text Available The autonomous navigation of robots is an important area of research. It can intelligently navigate itself from source to target within an environment without human interaction. Recently, algorithms and techniques have been made and developed to improve the performance of robots. It’s more effective and has high precision tasks than before. This work proposed to solve a maze using a Flood fill algorithm based on real time camera monitoring the movement on its environment. Live video streaming sends an obtained data to be processed by the server. The server sends back the information to the robot via wireless radio. The robot works as a client device moves from point to point depends on server information. Using camera in this work allows voiding great time that needs it to indicate the route by the robot.

  3. Omnidirectional autonomous entry guidance based on 3-D analytical glide formulas.

    Science.gov (United States)

    Yu, Wenbin; Chen, Wanchun; Jiang, Zhiguo; Liu, Xiaoming; Zhou, Hao

    2016-11-01

    An autonomous entry guidance law is developed based on 3-D analytical glide formulas, where the downrange formula is used to plan the longitudinal reference profile in order to meet the downrange and final energy requirements, and the crossrange formula is used to regulate the bank reversals in order to eliminate the crossrange error. As the analytical glide formulas ignore the effects of the Earth׳s rotation, a series of strategies is proposed for compensating these effects, which provides the guidance with the capability of steering the hypersonic glide vehicle with high Lift to Drag ratio (L/D) to any place of the world accurately. The compensation strategies can be summarized into two parts: (1) the reference profiles are properly adjusted by roughly evaluating the effects of the Earth׳s rotation on the aerodynamic profiles over the whole flight, which can compensate most of the effects; (2) the current effects are accurately evaluated and then the guidance commands are slightly modulated for compensating the remaining effects. Due to careful design, the strategies will not result in drastic changes in the Angle of Attack (AOA) and can keep the bank angle almost constant during most of flight.

  4. Ground-Based Phase of Spaceflight Experiment "Biosignal" Using Autonomic Microflurimeter "Fluor-K"

    Science.gov (United States)

    Grigorieva, O. V.; Gal'chuk, S. V.; Rudimov, E. G.; Buravkova, L. B.

    2013-02-01

    The majority of flight experiments with the use of cell cultures and equipment like KUBIK and CRIOGEM carried out on board of the satellites (Bion, Foton) and ISS only allows the after-flight biosamples to be analyzed. As far as with few exceptions, the real-time cellular parameters registration for a long period is hard to be implemented. We developed the "Fluor-K" equipment - precision, small-sized, autonomous, two-channel, programmed fluorimeter. This device is designed for registration of differential fluorescent signal from organic and non-organic objects of microscale in small volumes (cellular organelles suspensions, animal and human cells, unicellular algae, bacteria, various fluorescent colloid solutions). Beside that, "Fluor-K" allows simultaneous detection of temperature. The ground-based tests of the device proved successful. The developed software can support experimental schedules while real-time data registration with the built-in storage device allows changes in selected parameters to be analyzed using wide range of fluorescent probes.

  5. Use of In-Flight Data to Validate Mars Samle Return Autonomous RvD GNC

    DEFF Research Database (Denmark)

    Barrena, V.; Colmenarejo, P.; Suatoni, M.

    D is based on RF, camera and LIDAR measurements. It includes design, prototyping and verification at three different levels: algorithms design and verification in a Functional Engineering Simulator, SW demonstrator verified in Real Time Avionics Test Benching and Dynamic Test Benching. Moreover...

  6. Autonomous Vision-Based Tethered-Assisted Rover Docking

    Science.gov (United States)

    Tsai, Dorian; Nesnas, Issa A.D.; Zarzhitsky, Dimitri

    2013-01-01

    Many intriguing science discoveries on planetary surfaces, such as the seasonal flows on crater walls and skylight entrances to lava tubes, are at sites that are currently inaccessible to state-of-the-art rovers. The in situ exploration of such sites is likely to require a tethered platform both for mechanical support and for providing power and communication. Mother/daughter architectures have been investigated where a mother deploys a tethered daughter into extreme terrains. Deploying and retracting a tethered daughter requires undocking and re-docking of the daughter to the mother, with the latter being the challenging part. In this paper, we describe a vision-based tether-assisted algorithm for the autonomous re-docking of a daughter to its mother following an extreme terrain excursion. The algorithm uses fiducials mounted on the mother to improve the reliability and accuracy of estimating the pose of the mother relative to the daughter. The tether that is anchored by the mother helps the docking process and increases the system's tolerance to pose uncertainties by mechanically aligning the mating parts in the final docking phase. A preliminary version of the algorithm was developed and field-tested on the Axel rover in the JPL Mars Yard. The algorithm achieved an 80% success rate in 40 experiments in both firm and loose soils and starting from up to 6 m away at up to 40 deg radial angle and 20 deg relative heading. The algorithm does not rely on an initial estimate of the relative pose. The preliminary results are promising and help retire the risk associated with the autonomous docking process enabling consideration in future martian and lunar missions.

  7. Implementation & Flight Testing of IMPACT system for Autonomous ISR using Collaborating UAVs with Application to Wild Fire Monitoring Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SSCI and MIT propose to further develop, implement and test the Integrated Mission Planning & Autonomous Control Technology (IMPACT) system software for...

  8. Flight Software Design Choices Based on Criticality

    Science.gov (United States)

    Lee, Earl

    1999-01-01

    This slide presentation reviews the rationale behind flight software design as a function of criticality. The requirements of human rated systems implies a high criticality for the flight support software. Human life is dependent on correct operation of the software. Flexibility should be permitted when the consequences of software failure are not life threatening. This is also relevant for selecting Commercial Off the Shelf (COTS) software.

  9. Formal Assurance for Cognitive Architecture Based Autonomous Agent

    Science.gov (United States)

    Bhattacharyya, Siddhartha; Eskridge, Thomas; Neogi, Natasha; Carvalho, Marco

    2017-01-01

    Autonomous systems are designed and deployed in different modeling paradigms. These environments focus on specific concepts in designing the system. We focus our effort in the use of cognitive architectures to design autonomous agents to collaborate with humans to accomplish tasks in a mission. Our research focuses on introducing formal assurance methods to verify the behavior of agents designed in Soar, by translating the agent to the formal verification environment Uppaal.

  10. Fuzzy Logic Based Autonomous Parallel Parking System with Kalman Filtering

    Science.gov (United States)

    Panomruttanarug, Benjamas; Higuchi, Kohji

    This paper presents an emulation of fuzzy logic control schemes for an autonomous parallel parking system in a backward maneuver. There are four infrared sensors sending the distance data to a microcontroller for generating an obstacle-free parking path. Two of them mounted on the front and rear wheels on the parking side are used as the inputs to the fuzzy rules to calculate a proper steering angle while backing. The other two attached to the front and rear ends serve for avoiding collision with other cars along the parking space. At the end of parking processes, the vehicle will be in line with other parked cars and positioned in the middle of the free space. Fuzzy rules are designed based upon a wall following process. Performance of the infrared sensors is improved using Kalman filtering. The design method needs extra information from ultrasonic sensors. Starting from modeling the ultrasonic sensor in 1-D state space forms, one makes use of the infrared sensor as a measurement to update the predicted values. Experimental results demonstrate the effectiveness of sensor improvement.

  11. Autonomous Guidance, Navigation and Control

    Science.gov (United States)

    Bordano, A. J.; Mcswain, G. G.; Fernandes, S. T.

    1991-01-01

    The NASA Autonomous Guidance, Navigation and Control (GN&C) Bridging program is reviewed to demonstrate the program plan and GN&C systems for the Space Shuttle. The ascent CN&C system is described in terms of elements such as the general-purpose digital computers, sensors for the navigation subsystem, the guidance-system software, and the flight-control subsystem. Balloon-based and lidar wind soundings are used for operations assessment on the day of launch, and the guidance software is based on dedicated units for atmospheric powered flight, vacuum powered flight, and abort-specific situations. Optimization of the flight trajectories is discussed, and flight-control responses are illustrated for wavelengths of 500-6000 m. Alternate sensors are used for load relief, and adaptive GN&C systems based on alternate gain synthesis are used for systems failures.

  12. Autonomous, Decentralized Grid Architecture: Prosumer-Based Distributed Autonomous Cyber-Physical Architecture for Ultra-Reliable Green Electricity Networks

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-01-11

    GENI Project: Georgia Tech is developing a decentralized, autonomous, internet-like control architecture and control software system for the electric power grid. Georgia Tech’s new architecture is based on the emerging concept of electricity prosumers—economically motivated actors that can produce, consume, or store electricity. Under Georgia Tech’s architecture, all of the actors in an energy system are empowered to offer associated energy services based on their capabilities. The actors achieve their sustainability, efficiency, reliability, and economic objectives, while contributing to system-wide reliability and efficiency goals. This is in marked contrast to the current one-way, centralized control paradigm.

  13. Autonomous, In-Flight Crew Health Risk Management for Exploration-Class Missions: Leveraging the Integrated Medical Model for the Exploration Medical System Demonstration Project

    Science.gov (United States)

    Butler, D. J.; Kerstman, E.; Saile, L.; Myers, J.; Walton, M.; Lopez, V.; McGrath, T.

    2011-01-01

    The Integrated Medical Model (IMM) captures organizational knowledge across the space medicine, training, operations, engineering, and research domains. IMM uses this knowledge in the context of a mission and crew profile to forecast risks to crew health and mission success. The IMM establishes a quantified, statistical relationship among medical conditions, risk factors, available medical resources, and crew health and mission outcomes. These relationships may provide an appropriate foundation for developing an in-flight medical decision support tool that helps optimize the use of medical resources and assists in overall crew health management by an autonomous crew with extremely limited interactions with ground support personnel and no chance of resupply.

  14. QFD-based conceptual design of an autonomous underwater robot

    Directory of Open Access Journals (Sweden)

    Thip Pasawang

    2015-12-01

    Full Text Available Autonomous underwater robots in the past few years have been designed according to the individual concepts and experiences of the researchers. To design a robot, which meets all the requirements of potential users, is an advanced work. Hence, a systematic design method that could include users’ preferences and requirements is needed. This paper presents the quality function deployment (QFD technique to design an autonomous underwater robot focusing on the Thai Navy military mission. Important user requirements extracted from the QFD method are the ability to record videos, operating at depth up to 10 meters, the ability to operate remotely with cable and safety concerns related to water leakages. Less important user requirements include beauty, using renewable energy, operating remotely with radio and ability to work during night time. The important design parameters derived from the user requirements are a low cost-controller, an autonomous control algorithm, a compass sensor and vertical gyroscope, and a depth sensor. Of low-importance ranked design parameters include the module design, use clean energy, a low noise electric motor, remote surveillance design, a pressure hull, and a beautiful hull form design. The study results show the feasibility of using QFD techniques to systematically design the autonomous underwater robot to meet user requirements. Mapping between the design and expected parameters and a conceptual drafting design of an autonomous underwater robot are also presented.

  15. Cognitive Networks Autonomic Decision-making Approach Based on Influence Diagram

    Directory of Open Access Journals (Sweden)

    Jin Qi

    2012-05-01

    Full Text Available The current research focus on the areas such as definition and system structure of cognitive networks (CNs, with the lack of autonomic decision-making theory and approach. In this paper, we proposed an autonomic decision-making approach based on influence diagram for CNs. Utilizing influence diagram to choose and execute the action which maximized the network overall performance can effectively predict the trend in network performance, archive autonomic decision-making and avoid network performance deterioration. The simulation results show that the CNs autonomic decision-making approach given network the abilities of learning, reasoning and autonomic decision-making without any human intervention. As a result, the network cognition has been archived while the network Quality of Service (QoS has been guaranteed.

  16. Vision Based Autonomous Robotic Control for Advanced Inspection and Repair

    Science.gov (United States)

    Wehner, Walter S.

    2014-01-01

    The advanced inspection system is an autonomous control and analysis system that improves the inspection and remediation operations for ground and surface systems. It uses optical imaging technology with intelligent computer vision algorithms to analyze physical features of the real-world environment to make decisions and learn from experience. The advanced inspection system plans to control a robotic manipulator arm, an unmanned ground vehicle and cameras remotely, automatically and autonomously. There are many computer vision, image processing and machine learning techniques available as open source for using vision as a sensory feedback in decision-making and autonomous robotic movement. My responsibilities for the advanced inspection system are to create a software architecture that integrates and provides a framework for all the different subsystem components; identify open-source algorithms and techniques; and integrate robot hardware.

  17. Colour-based Object Detection and Tracking for Autonomous Quadrotor UAV

    Science.gov (United States)

    Kadouf, Hani Hunud A.; Mohd Mustafah, Yasir

    2013-12-01

    With robotics becoming a fundamental aspect of modern society, further research and consequent application is ever increasing. Aerial robotics, in particular, covers applications such as surveillance in hostile military zones or search and rescue operations in disaster stricken areas, where ground navigation is impossible. The increased visual capacity of UAV's (Unmanned Air Vehicles) is also applicable in the support of ground vehicles to provide supplies for emergency assistance, for scouting purposes or to extend communication beyond insurmountable land or water barriers. The Quadrotor, which is a small UAV has its lift generated by four rotors and can be controlled by altering the speeds of its motors relative to each other. The four rotors allow for a higher payload than single or dual rotor UAVs, which makes it safer and more suitable to carry camera and transmitter equipment. An onboard camera is used to capture and transmit images of the Quadrotor's First Person View (FPV) while in flight, in real time, wirelessly to a base station. The aim of this research is to develop an autonomous quadrotor platform capable of transmitting real time video signals to a base station for processing. The result from the image analysis will be used as a feedback in the quadrotor positioning control. To validate the system, the algorithm should have the capacity to make the quadrotor identify, track or hover above stationary or moving objects.

  18. Autonomous navigation system based on GPS and magnetometer data

    Science.gov (United States)

    Julie, Thienel K. (Inventor); Richard, Harman R. (Inventor); Bar-Itzhack, Itzhack Y. (Inventor)

    2004-01-01

    This invention is drawn to an autonomous navigation system using Global Positioning System (GPS) and magnetometers for low Earth orbit satellites. As a magnetometer is reliable and always provides information on spacecraft attitude, rate, and orbit, the magnetometer-GPS configuration solves GPS initialization problem, decreasing the convergence time for navigation estimate and improving the overall accuracy. Eventually the magnetometer-GPS configuration enables the system to avoid costly and inherently less reliable gyro for rate estimation. Being autonomous, this invention would provide for black-box spacecraft navigation, producing attitude, orbit, and rate estimates without any ground input with high accuracy and reliability.

  19. Semiconductor Nanomembrane based Flight Sensors and Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA Phase I program would develop and demonstrate semiconductor nanomembrane (NM) based flight sensors and arrays on flexible substrates, using SOI (Silicon on...

  20. Knowledge-based system for flight information management. Thesis

    Science.gov (United States)

    Ricks, Wendell R.

    1990-01-01

    The use of knowledge-based system (KBS) architectures to manage information on the primary flight display (PFD) of commercial aircraft is described. The PFD information management strategy used tailored the information on the PFD to the tasks the pilot performed. The KBS design and implementation of the task-tailored PFD information management application is described. The knowledge acquisition and subsequent system design of a flight-phase-detection KBS is also described. The flight-phase output of this KBS was used as input to the task-tailored PFD information management KBS. The implementation and integration of this KBS with existing aircraft systems and the other KBS is described. The flight tests are examined of both KBS's, collectively called the Task-Tailored Flight Information Manager (TTFIM), which verified their implementation and integration, and validated the software engineering advantages of the KBS approach in an operational environment.

  1. Autonomous vision in space, based on Advanced Stellar Compass platform

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Eisenman, Allan R.; Liebe, Carl Christian

    1996-01-01

    The Ørsted Star Imager, comprises the functionality of an Advanced Stellar Compass (ASC). I.e. it is able to, autonomously solve "the lost in space" attitude problem, as well as determine the attitude with high precision in the matter of seconds. The autonomy makes for a high capability for error...

  2. Optic-flow based slope estimation for autonomous landing

    NARCIS (Netherlands)

    De Croon, G.C.H.E.; Ho, H.W.; De Wagter, C.; Van Kampen, E.; Remes, B.; Chu, Q.P.

    2013-01-01

    Micro Air Vehicles need to have a robust landing capability, especially when they operate outside line-of-sight. Autonomous landing requires the identification of a relatively flat landing surface that does not have too large an inclination. In this article, a vision algorithm is introduced that fit

  3. Cooperative Game Study of Airlines Based on Flight Frequency Optimization

    Directory of Open Access Journals (Sweden)

    Wanming Liu

    2014-01-01

    Full Text Available By applying the game theory, the relationship between airline ticket price and optimal flight frequency is analyzed. The paper establishes the payoff matrix of the flight frequency in noncooperation scenario and flight frequency optimization model in cooperation scenario. The airline alliance profit distribution is converted into profit distribution game based on the cooperation game theory. The profit distribution game is proved to be convex, and there exists an optimal distribution strategy. The results show that joining the airline alliance can increase airline whole profit, the change of negotiated prices and cost is beneficial to profit distribution of large airlines, and the distribution result is in accordance with aviation development.

  4. DualTrust: A Trust Management Model for Swarm-Based Autonomic Computing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Maiden, Wendy M. [Washington State Univ., Pullman, WA (United States)

    2010-05-01

    Trust management techniques must be adapted to the unique needs of the application architectures and problem domains to which they are applied. For autonomic computing systems that utilize mobile agents and ant colony algorithms for their sensor layer, certain characteristics of the mobile agent ant swarm -- their lightweight, ephemeral nature and indirect communication -- make this adaptation especially challenging. This thesis looks at the trust issues and opportunities in swarm-based autonomic computing systems and finds that by monitoring the trustworthiness of the autonomic managers rather than the swarming sensors, the trust management problem becomes much more scalable and still serves to protect the swarm. After analyzing the applicability of trust management research as it has been applied to architectures with similar characteristics, this thesis specifies the required characteristics for trust management mechanisms used to monitor the trustworthiness of entities in a swarm-based autonomic computing system and describes a trust model that meets these requirements.

  5. UPF based autonomous navigation scheme for deep space probe

    Institute of Scientific and Technical Information of China (English)

    Li Peng; Cui Hutao; Cui Pingyuan

    2008-01-01

    The autonomous "celestial navigation scheme" for deep space probe departing from the earth and the autonomous "optical navigation scheme" for encountering object celestial body are presented. Then, aiming at the conditions that large initial estimation errors and non-Gaussian distribution of state or measurement errors may exist in orbit determination process of the two phases, UPF (unscented particle filter) is introduced into the navigation schemes. By tackling nonlinear and non-Gaussian problems, UPF overcomes the accuracy influence brought by the traditional EKF (extended Kalman filter), UKF (unscented Kalman filter), and PF (particle filter) schemes in approximate treatment to nonlinear and non-Gaussian state model and measurement model. The numerical simulations demonstrate the feasibility and higher accuracy of the UPF navigation scheme.

  6. 3D Vision Based Landing Control of a Small Scale Autonomous Helicopter

    OpenAIRE

    Zhenyu Yu; Kenzo Nonami; Jinok Shin; Demian Celestino

    2007-01-01

    Autonomous landing is a challenging but important task for Unmanned Aerial Vehicles (UAV) to achieve high level of autonomy. The fundamental requirement for landing is the knowledge of the height above the ground, and a properly designed controller to govern the process. This paper presents our research results in the study of landing an autonomous helicopter. The abovetheground height sensing is based on a 3D vision system. We have designed a simple planefitting method for e...

  7. Load Sharing of Wind Based Microgrid in Autonomous Operation

    Directory of Open Access Journals (Sweden)

    Aarti Gupta

    2014-01-01

    Full Text Available Autonomous wind energy conversion systems sharing a common load consist of a number of voltage source converters operating in parallel. A suitable control system should ensure desired load sharing among these as a number of these sources operating in parallel are required to meet the load demand and load excursions should not lead to instability of the system. In absence of the grid there is no reference angle for synchronization. Hence, a control scheme for parallel-connected three-phase converters incorporating the desirable features needs to be developed in order to exploit the renewable energy sources, which are intermittent in nature as effectively as possible in case of an autonomous microgrid. A simple and effective droop control strategy without the use of conventional αβ technique incorporating only dq components has been proposed for load sharing among wind energy conversion systems connected by back to back voltage source converters in autonomous operation. The need for communication link should also be avoided, hence reducing the system cost. The system is modelled using Matlab and the control is authenticated by simulation results.

  8. An Autonomous Observation and Control System Based on EPICS and RTS2 for Antarctic Telescopes

    CERN Document Server

    Zhang, Guang-Yu; Tang, Peng-Yi; Jia, Ming-Hao; Chen, Jie; Dong, Shu-Cheng; Jiang, Fengxin; Wu, Wen-Qing; Liu, Jia-Jing; Zhang, Hong-Fei

    2015-01-01

    For an unattended telescopes in Antarctic, the remote operation, autonomous observation and control are essential. An EPICS (Experimental Physics and Industrial Control System) and RTS2(Remote Telescope System, 2nd Version) based autonomous observation and control system with remoted operation is introduced in this paper. EPICS is a set of Open Source software tools, libraries and applications developed collaboratively and used worldwide to create distributed soft real-time control systems for scientific instruments while RTS2 is an open source environment for control of a fully autonomous observatory. Using the advantage of EPICS and RTS2 respectively, a combined integrated software framework for autonomous observation and control is established that use RTS2 to fulfill the function of astronomical observation and use EPICS to fulfill the device control of telescope. A command and status interface for EPICS and RTS2 is designed to make the EPICS IOC (Input/Output Controller) components integrate to RTS2 dire...

  9. An autonomous observation and control system based on EPICS and RTS2 for Antarctic telescopes

    Science.gov (United States)

    Zhang, Guang-yu; Wang, Jian; Tang, Peng-yi; Jia, Ming-hao; Chen, Jie; Dong, Shu-cheng; Jiang, Fengxin; Wu, Wen-qing; Liu, Jia-jing; Zhang, Hong-fei

    2016-01-01

    For unattended telescopes in Antarctic, the remote operation, autonomous observation and control are essential. An EPICS-(Experimental Physics and Industrial Control System) and RTS2-(Remote Telescope System, 2nd Version) based autonomous observation and control system with remoted operation is introduced in this paper. EPICS is a set of open source software tools, libraries and applications developed collaboratively and used worldwide to create distributed soft real-time control systems for scientific instruments while RTS2 is an open source environment for control of a fully autonomous observatory. Using the advantage of EPICS and RTS2, respectively, a combined integrated software framework for autonomous observation and control is established that use RTS2 to fulfil the function of astronomical observation and use EPICS to fulfil the device control of telescope. A command and status interface for EPICS and RTS2 is designed to make the EPICS IOC (Input/Output Controller) components integrate to RTS2 directly. For the specification and requirement of control system of telescope in Antarctic, core components named Executor and Auto-focus for autonomous observation is designed and implemented with remote operation user interface based on browser-server mode. The whole system including the telescope is tested in Lijiang Observatory in Yunnan Province for practical observation to complete the autonomous observation and control, including telescope control, camera control, dome control, weather information acquisition with the local and remote operation.

  10. On-line Autonomous Learning Based on Leamerg Expectation

    Institute of Scientific and Technical Information of China (English)

    李利娜

    2008-01-01

    On-line autonomous learning of College English is one of the important reforms in colleges recently.This paper aims to explore the changes of teachers'role in the new on-line setting.The article first reviews the theoretical study of learner autonomy,then makes a practical investigation into the attitude and expectation learners have on teachers through a self-designed questionnaire,and explores that teachers should make an adjustment to their role orientation and changes their roles into motivators,evaluators and resources supphers in the new on-line setting.

  11. Autonomous vision in space, based on Advanced Stellar Compass platform

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Eisenman, Allan R.; Liebe, Carl Christian

    1996-01-01

    The Ørsted Star Imager, comprises the functionality of an Advanced Stellar Compass (ASC). I.e. it is able to, autonomously solve "the lost in space" attitude problem, as well as determine the attitude with high precision in the matter of seconds. The autonomy makes for a high capability for error......) Complex Object surface tracking (e.g. space docking, planetary terrain tracking). All the above topics, has been realized in the past. Either by open loop, or by man-in-loop systems. By implementing these methods or function in the onboard autonomy, a superior system performance could be acheived by means...

  12. Autonomous vision in space, based on Advanced Stellar Compass platform

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Eisenman, Allan R.; Liebe, Carl Christian

    1996-01-01

    rejection and fault recovery, as well as graceful degradation at radiation, false object or thermal loads. The instrument was developed from Concept to Flight Model within 3 Years. The instrument surpasses the initial specifications for all parameters. For Precision, Computational speed and Fault detection...

  13. Outdoor field experience with autonomous RPC based stations

    Science.gov (United States)

    Lopes, L.; Assis, P.; Blanco, A.; Carolino, N.; Cerda, M. A.; Conceição, R.; Cunha, O.; Ferreira, M.; Fonte, P.; Luz, R.; Mendes, L.; Pereira, A.; Pimenta, M.; Sarmento, R.; Tomé, B.

    2016-09-01

    In the last two decades Resistive Plate Chambers were employed in the Cosmic Ray Experiments COVER-PLASTEX and ARGO/YBJ. In both experiments the detectors were housed indoors, likely owing to gas distribution requirements and the need to control environment variables that directly affect RPCs operational stability. But in experiments where Extended Air Shower (EAS) sampling is necessary, large area arrays composed by dispersed stations are deployed, rendering this kind of approach impossible. In this situation, it would be mandatory to have detectors that could be deployed in small standalone stations, with very rare opportunities for maintenance, and with good resilience to environmental conditions. Aiming to meet these requirements, we started some years ago the development of RPCs for Autonomous Stations. The results from indoor tests and measurements were very promising, both concerning performance and stability under very low gas flow rate, which is the main requirement for Autonomous Stations. In this work we update the indoor results and show the first ones concerning outdoor stable operation. In particular, a dynamic adjustment of the high voltage is applied to keep gas gain constant.

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

    Science.gov (United States)

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

    2006-01-01

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

  15. An autonomous miniature wheeled robot based on visual feedback control

    Institute of Scientific and Technical Information of China (English)

    CHEN Haichu

    2007-01-01

    Using two micro-motors,a novel omni-direction miniature wheeled robot is designed on the basis of the bi-corner driving principle.The robot takes advantage of the Bluetooth technology to wirelessly transmit data at a short distance.Its position and omni-direction motion are precise.A Charge Coupled Device(CCD)camera is used for measuring and for visual navigation.A control system is developed.The precision of the position is 0.5 mm,the resolution is about 0.05 mm,and the maximum velocity is about 52 mm/s.The visual navigation and control system allow the robot to navigate and track the target and to accomplish autonomous locomotion.

  16. Micro-Controller Based Obstacle Avoiding Autonomous Robot

    Directory of Open Access Journals (Sweden)

    Subhranil Som

    2014-06-01

    Full Text Available Main aim of this paperwork is to study development of the obstacle avoiding spy robot, which can be operated manually as per the operator wants to take control of the robot himself, it also can be autonomous in its actions while intelligently moving itself by detecting the obstacles in front of it by the help of the obstacle detectable circuit. The robot is in form of a vehicle mounted with a web cam, which acquires and sends video as per the robots eye view to a TV or PC via a TV tuner card. The microcontroller chip ATMEGA 328 present on the microcontroller board ARDUINO controls the movements of the robot. In manual operating conditions the user will have a radio transmitter (tx via which the user will send signal to the radio receiver (rx present inside the robot which accordingly will pass on the signal to the microcontroller board, and as per the coding of the signal signatures burnt inside the microcontroller chip the robot will complete its movements. In Autonomous operating conditions the user will have no control on the robot that is the robot cannot be operated via any external controls, it will only function as per the data received from the obstacle detection circuits to the microcontroller which will make the robot motors move accordingly as per the code written in it. The idea is to make a robot to tackle the hostage situations & cope up with the worst conditions, which can be quiet a matter of risk to be handled by human being.

  17. Integrating disparity and edge detection algorithms to autonomously follow linear-shaped structures at low altitude

    NARCIS (Netherlands)

    C.R. Verschoor; A. Visser

    2013-01-01

    One of the main requirements in enabling autonomous flight of Micro Aerial Vehicles is the ability of autonomous navigation. One possible solution to solve this navigation problem is to use vision-based line-following algorithms. Such vision-based algorithm could rely on the various linear structure

  18. A Review of the Effectiveness of Web-based Course with College English Learners'Autonomous Learning

    Institute of Scientific and Technical Information of China (English)

    杜淑珍

    2015-01-01

    The paper is a literature review,aiming to examine the effectiveness of web-based college English learning which mainly focuses on learners'autonomous learning.Previous studies indicate that the web-based learning can improve learners' autonomous learning,as well as some problems found in their findings.Therefore,this paper first gives a summary and critique of research studies on the web-based autonomous learning and some factors influencing learners'autonomous learning ability;then,areas that deserve further study are also indicated.

  19. Current Situation of English Major Students’ Web-based Autonomous English Learning

    Institute of Scientific and Technical Information of China (English)

    李新华

    2015-01-01

    Through an interview of three English major students and a field observation, the study explores English major students’ web-based autonomous English learning situation and the problems on their way. The findings show that web-based English materials are most helpful to speaking and listening, and that students’ insufficient information retrieval skill is the main problem on their way.

  20. Immersion and Invariance Based Nonlinear Adaptive Flight Control

    NARCIS (Netherlands)

    Sonneveldt, L.; Van Oort, E.R.; Chu, Q.P.; Mulder, J.A.

    2010-01-01

    In this paper a theoretical framework for nonlinear adaptive flight control is developed and applied to a simplified, over-actuated nonlinear fighter aircraft model. The framework is based on a modular adaptive backstepping scheme with a new type of nonlinear estimator. The nonlinear estimator is

  1. Immersion and Invariance Based Nonlinear Adaptive Flight Control

    NARCIS (Netherlands)

    Sonneveldt, L.; Van Oort, E.R.; Chu, Q.P.; Mulder, J.A.

    2010-01-01

    In this paper a theoretical framework for nonlinear adaptive flight control is developed and applied to a simplified, over-actuated nonlinear fighter aircraft model. The framework is based on a modular adaptive backstepping scheme with a new type of nonlinear estimator. The nonlinear estimator is co

  2. Autonomous Control Reconfiguration of Aerospace Vehicle Based on Control Effectiveness Estimation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Future aerospace vehicles (ASV) are designed to fly in both inner and extra atrmospheric fields, which requires autonomous adaptability to the uncertainties emanated from abrupt faults and continuously time-varying environments. An autonomous control reconfiguration scheme is presented for ASV to deal with the uncertainties on the base of control effectiveness estimation. The on-line estimation methods for the time-varying control effectiveness of linear control system are investigated. Some sufficient conditions for the estimable system are given for different cases. There are proposed corresponding on-line estimation algorithms which are proved to be convergent and robust to noise using the least-square-based methods. On the ground of fuzzy logic and linear programming, the control allocation algorithms, which are able to implement the autonomous control reconfiguration through the redundant actuators, are put forward. Finally, an integrated system is developed to verify the scheme and algorithms by way of numerical simulation and analysis.

  3. Three-Dimensional Path Planning Method for Autonomous Underwater Vehicle Based on Modified Firefly Algorithm

    Directory of Open Access Journals (Sweden)

    Chang Liu

    2015-01-01

    Full Text Available Path planning is a classic optimization problem which can be solved by many optimization algorithms. The complexity of three-dimensional (3D path planning for autonomous underwater vehicles (AUVs requires the optimization algorithm to have a quick convergence speed. This work provides a new 3D path planning method for AUV using a modified firefly algorithm. In order to solve the problem of slow convergence of the basic firefly algorithm, an improved method was proposed. In the modified firefly algorithm, the parameters of the algorithm and the random movement steps can be adjusted according to the operating process. At the same time, an autonomous flight strategy is introduced to avoid instances of invalid flight. An excluding operator was used to improve the effect of obstacle avoidance, and a contracting operator was used to enhance the convergence speed and the smoothness of the path. The performance of the modified firefly algorithm and the effectiveness of the 3D path planning method were proved through a varied set of experiments.

  4. LABRADOR: a learning autonomous behavior-based robot for adaptive detection and object retrieval

    Science.gov (United States)

    Yamauchi, Brian; Moseley, Mark; Brookshire, Jonathan

    2013-01-01

    As part of the TARDEC-funded CANINE (Cooperative Autonomous Navigation in a Networked Environment) Program, iRobot developed LABRADOR (Learning Autonomous Behavior-based Robot for Adaptive Detection and Object Retrieval). LABRADOR was based on the rugged, man-portable, iRobot PackBot unmanned ground vehicle (UGV) equipped with an explosives ordnance disposal (EOD) manipulator arm and a custom gripper. For LABRADOR, we developed a vision-based object learning and recognition system that combined a TLD (track-learn-detect) filter based on object shape features with a color-histogram-based object detector. Our vision system was able to learn in real-time to recognize objects presented to the robot. We also implemented a waypoint navigation system based on fused GPS, IMU (inertial measurement unit), and odometry data. We used this navigation capability to implement autonomous behaviors capable of searching a specified area using a variety of robust coverage strategies - including outward spiral, random bounce, random waypoint, and perimeter following behaviors. While the full system was not integrated in time to compete in the CANINE competition event, we developed useful perception, navigation, and behavior capabilities that may be applied to future autonomous robot systems.

  5. Flight system design for a receiver aircraft to perform autonomous aerial refueling provided with relative position data link

    Science.gov (United States)

    Awni, Kahtan A.

    An automatic aerial refueling system was developed that is capable of controlling the receiving aircraft to rendezvous, dock and station keep the receiver refueling probe in the tanker refueling probe. The automatic refueling system consisted of an active trajectory generator, a guidance system and a control system. The active trajectory generator continuously updated the commanded rendezvous trajectory to be flown by the receiver aircraft. This active trajectory generator concept incorporated design variables that the designer could use to specify the time sequence of the rendezvous and docking maneuver. The output of the trajectory generator was then the command to the flight systems guidance and control systems. To demonstrate this automatic aerial refueling system concept, a detailed design of the flight system algorithms was done for typical aerial refueling mission with a heavy jet tanker aircraft similar to the KC135 and the SIAI-Marchetti S-211 Jet Trainer as a receiver aircraft. The systems gains were selected to minimize the control surface activity while achieving adequate tracking. A simulation was developed that included the flight system algorithms, linear models of the receiver aircraft, atmospheric and tanker wake disturbance models. The performance of the aerial refueling system design was then evaluated in a batch computer simulator. The simulation study demonstrated results showed better disturbance rejection relative to the controller performance while minimizing the utilization of the control surfaces. Results also demonstrated the ability to schedule rendezvous.

  6. A Self-Optimization Method for System Service Dependability based on Autonomic Computing

    Directory of Open Access Journals (Sweden)

    Qingtao Wu

    2012-11-01

    Full Text Available Under the intrusion or abnormal attacks, how to supply system service dependability autonomously, without being degraded, is the essential requirement to network system service. Autonomic Computing can overcome the heterogeneity and complexity of computing system, has been regarded as a novel and effective approach to implementing autonomous systems to address system security issues. To cope with the problem of declining network service dependability caused by safety threats, we proposed an autonomic method for optimizing system service performance based on Q-learning from the perspective of autonomic computing. First, we get the operations by utilizing the nonlinear mapping relations of the feedforward neural network. Then, we obtain the executive action by perceiving the state parameter changes of the network system in the service performance. Thirdly, we calculate the environment-rewarded function value integrated the changes of the system service performance and the service availability. Finally, we use the self-learning characteristics and prediction ability of the Q-learning to make the system service to achieve optimal performance. Simulation results show that this method is effective for optimizing the overall dependability and service utility of a system.

  7. A New Kind of Art [Based on Autonomous Collective Robotics

    Directory of Open Access Journals (Sweden)

    Leonel Moura

    2014-11-01

    Full Text Available The paper addresses the rationale of a process that produces artworks made by a swarm of robots. This process relies on the interaction, though the environment, of a set of robots designed to create spatiotemporal patterns from an initial homogeneous medium (the canvas. Inspired by social insect societies, the approach presented here exploits robot-robot and robot-environment interactions to develop emergent behaviour. The swarm intelligence concept is crucial to this approach because the viability of the team (group of robots is required in order to achieve the viability of the individual. Without any central coordination or plan, the group of robots produces its artworks on the basis of a data-driven (bottom-up process. Moreover, each robot can be viewed as an autonomous agent because it has on board all the resources required to provide the global outcome of the experiment, including sensors, actuators, and the controller, which demonstrates a reactive behaviour by reinforcing a previously made signal (positive feedback. The process is also presented in the context of Machine Art, and a detailed technical description of each robot is given, as well as an example of artworks produced by the collective behaviour of the set of robots.

  8. Street Viewer: An Autonomous Vision Based Traffic Tracking System.

    Science.gov (United States)

    Bottino, Andrea; Garbo, Alessandro; Loiacono, Carmelo; Quer, Stefano

    2016-06-03

    The development of intelligent transportation systems requires the availability of both accurate traffic information in real time and a cost-effective solution. In this paper, we describe Street Viewer, a system capable of analyzing the traffic behavior in different scenarios from images taken with an off-the-shelf optical camera. Street Viewer operates in real time on embedded hardware architectures with limited computational resources. The system features a pipelined architecture that, on one side, allows one to exploit multi-threading intensively and, on the other side, allows one to improve the overall accuracy and robustness of the system, since each layer is aimed at refining for the following layers the information it receives as input. Another relevant feature of our approach is that it is self-adaptive. During an initial setup, the application runs in learning mode to build a model of the flow patterns in the observed area. Once the model is stable, the system switches to the on-line mode where the flow model is used to count vehicles traveling on each lane and to produce a traffic information summary. If changes in the flow model are detected, the system switches back autonomously to the learning mode. The accuracy and the robustness of the system are analyzed in the paper through experimental results obtained on several different scenarios and running the system for long periods of time.

  9. Street Viewer: An Autonomous Vision Based Traffic Tracking System

    Science.gov (United States)

    Bottino, Andrea; Garbo, Alessandro; Loiacono, Carmelo; Quer, Stefano

    2016-01-01

    The development of intelligent transportation systems requires the availability of both accurate traffic information in real time and a cost-effective solution. In this paper, we describe Street Viewer, a system capable of analyzing the traffic behavior in different scenarios from images taken with an off-the-shelf optical camera. Street Viewer operates in real time on embedded hardware architectures with limited computational resources. The system features a pipelined architecture that, on one side, allows one to exploit multi-threading intensively and, on the other side, allows one to improve the overall accuracy and robustness of the system, since each layer is aimed at refining for the following layers the information it receives as input. Another relevant feature of our approach is that it is self-adaptive. During an initial setup, the application runs in learning mode to build a model of the flow patterns in the observed area. Once the model is stable, the system switches to the on-line mode where the flow model is used to count vehicles traveling on each lane and to produce a traffic information summary. If changes in the flow model are detected, the system switches back autonomously to the learning mode. The accuracy and the robustness of the system are analyzed in the paper through experimental results obtained on several different scenarios and running the system for long periods of time. PMID:27271627

  10. An autonomous sensor module based on a legacy CCTV camera

    Science.gov (United States)

    Kent, P. J.; Faulkner, D. A. A.; Marshall, G. F.

    2016-10-01

    A UK MoD funded programme into autonomous sensors arrays (SAPIENT) has been developing new, highly capable sensor modules together with a scalable modular architecture for control and communication. As part of this system there is a desire to also utilise existing legacy sensors. The paper reports upon the development of a SAPIENT-compliant sensor module using a legacy Close-Circuit Television (CCTV) pan-tilt-zoom (PTZ) camera. The PTZ camera sensor provides three modes of operation. In the first mode, the camera is automatically slewed to acquire imagery of a specified scene area, e.g. to provide "eyes-on" confirmation for a human operator or for forensic purposes. In the second mode, the camera is directed to monitor an area of interest, with zoom level automatically optimized for human detection at the appropriate range. Open source algorithms (using OpenCV) are used to automatically detect pedestrians; their real world positions are estimated and communicated back to the SAPIENT central fusion system. In the third mode of operation a "follow" mode is implemented where the camera maintains the detected person within the camera field-of-view without requiring an end-user to directly control the camera with a joystick.

  11. Adaptive Source Localization Based Station Keeping of Autonomous Vehicles

    KAUST Repository

    Guler, Samet

    2016-10-26

    We study the problem of driving a mobile sensory agent to a target whose location is specied only in terms of the distances to a set of sensor stations or beacons. The beacon positions are unknown, but the agent can continuously measure its distances to them as well as its own position. This problem has two particular applications: (1) capturing a target signal source whose distances to the beacons are measured by these beacons and broadcasted to a surveillance agent, (2) merging a single agent to an autonomous multi-agent system so that the new agent is positioned at desired distances from the existing agents. The problem is solved using an adaptive control framework integrating a parameter estimator producing beacon location estimates, and an adaptive motion control law fed by these estimates to steer the agent toward the target. For location estimation, a least-squares adaptive law is used. The motion control law aims to minimize a convex cost function with unique minimizer at the target location, and is further augmented for persistence of excitation. Stability and convergence analysis is provided, as well as simulation results demonstrating performance and transient behavior.

  12. Local sampling for indoor flight

    NARCIS (Netherlands)

    De Croon, G.C.H.E.; De Wagter, C.; Remes, B.D.W.; Ruijsink, H.M.

    2009-01-01

    A challenging problem in artificial intelligence is to achieve vision-based autonomous indoor flight with Micro Air Vehicles. Approaches to this problem currently do not make use of image appearance features, because these features generally are computationally expensive. In this article, we deliver

  13. The Intellectualized Architecture of the Autonomous Micro-Mobile Robot Based-Behavior

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Given the difficulty in hand-coding task schemes, an intellectualized architecture of the autonomous micro-mobile robot based-behavior for fault-repair was presented. Integrating the reinforcement learning and the group behavior evolution simulating the human's learning and evolution, the autonomous micro-mobile robot will automatically generate the suited actions satisfied the environment. However, the designer only devises some basic behaviors, which decreases the workload of the designer and cognitive deficiency of the robot to the environment. The results of simulation have shown that the architecture endows micro robot with the ability of learning, adaptation and robustness, also with the ability of accomplishing the given task.

  14. A web service based tool to plan atmospheric research flights

    Directory of Open Access Journals (Sweden)

    M. Rautenhaus

    2011-09-01

    Full Text Available We present a web service based tool for the planning of atmospheric research flights. The tool provides online access to horizontal maps and vertical cross-sections of numerical weather prediction data and in particular allows the interactive design of a flight route in direct relation to the predictions. It thereby fills a crucial gap in the set of currently available tools for using data from numerical atmospheric models for research flight planning. A distinct feature of the tool is its lightweight, web service based architecture, requiring only commodity hardware and a basic Internet connection for deployment. Access to visualisations of prediction data is achieved by using an extended version of the Open Geospatial Consortium Web Map Service (WMS standard, a technology that has gained increased attention in meteorology in recent years. With the WMS approach, we avoid the transfer of large forecast model output datasets while enabling on-demand generated visualisations of the predictions at campaign sites with limited Internet bandwidth. Usage of the Web Map Service standard also enables access to third-party sources of georeferenced data. We have implemented the software using the open-source programming language Python. In the present article, we describe the architecture of the tool. As an example application, we discuss a case study research flight planned for the scenario of the 2010 Eyjafjalla volcano eruption. Usage and implementation details are provided as Supplement.

  15. Overheating Anomalies during Flight Test Due to the Base Bleeding

    Science.gov (United States)

    Luchinsky, Dmitry; Hafiychuck, Halyna; Osipov, Slava; Ponizhovskaya, Ekaterina; Smelyanskiy, Vadim; Dagostino, Mark; Canabal, Francisco; Mobley, Brandon L.

    2012-01-01

    In this paper we present the results of the analytical and numerical studies of the plume interaction with the base flow in the presence of base out-gassing. The physics-based analysis and CFD modeling of the base heating for single solid rocket motor performed in this research addressed the following questions: what are the key factors making base flow so different from that in the Shuttle [1]; why CFD analysis of this problem reveals small plume recirculation; what major factors influence base temperature; and why overheating was initiated at a given time in the flight. To answer these questions topological analysis of the base flow was performed and Korst theory was used to estimate relative contributions of radiation, plume recirculation, and chemically reactive out-gassing to the base heating. It was shown that base bleeding and small base volume are the key factors contributing to the overheating, while plume recirculation is effectively suppressed by asymmetric configuration of the flow formed earlier in the flight. These findings are further verified using CFD simulations that include multi-species gas environment both in the plume and in the base. Solid particles in the exhaust plume (Al2O3) and char particles in the base bleeding were also included into the simulations and their relative contributions into the base temperature rise were estimated. The results of simulations are in good agreement with the temperature and pressure in the base measured during the test.

  16. Autonomous Learning through Task-Based Instruction in Fully Online Language Courses

    Science.gov (United States)

    Lee, Lina

    2016-01-01

    This study investigated the affordances for autonomous learning in a fully online learning environment involving the implementation of task-based instruction in conjunction with Web 2.0 technologies. To that end, four-skill-integrated tasks and digital tools were incorporated into the coursework. Data were collected using midterm reflections,…

  17. Chinese Students' Goal Orientation in English Learning: A Study Based on Autonomous Inquiry Model

    Science.gov (United States)

    Zhang, Jianfeng

    2014-01-01

    Goal orientation is a kind of theory of learning motivation, which helps learners to develop their capability by emphasis on new techniques acquiring and environment adapting. In this study, based on the autonomous inquiry model, the construction of Chinese students' goal orientations in English learning are summarized according to the data…

  18. Energy-autonomous wireless vibration sensor for condition-based maintenance of machinery

    NARCIS (Netherlands)

    Wang, Z.; Bouwens, F.; Vullers, R.; Petré, F.; Devos, S.

    2011-01-01

    This paper addresses the development of an energy-autonomous wireless vibration sensor for condition-based monitoring of machinery. Such technology plays an increasingly important role in modern manufacturing industry. In this work, energy harvesting is realized by resorting to a custom designed the

  19. Energy-autonomous wireless vibration sensor for condition-based maintenance of machinery

    NARCIS (Netherlands)

    Wang, Z.; Bouwens, F.; Vullers, R.; Petré, F.; Devos, S.

    2011-01-01

    This paper addresses the development of an energy-autonomous wireless vibration sensor for condition-based monitoring of machinery. Such technology plays an increasingly important role in modern manufacturing industry. In this work, energy harvesting is realized by resorting to a custom designed

  20. Indoor Autonomous Airship Control and Navigation System

    Directory of Open Access Journals (Sweden)

    Fedorenko Roman

    2016-01-01

    Full Text Available The paper presents an automatic control system for autonomous airship. The system is designed to organize autonomous flight of the mini-airship performing flight mission defined from ground control station. Structure, hardware and software implementation of indoor autonomous airship and its navigation and control system as well as experiment results are described.

  1. Bayesian Network Assessment Method for Civil Aviation Safety Based on Flight Delays

    OpenAIRE

    2013-01-01

    Flight delays and safety are the principal contradictions in the sound development of civil aviation. Flight delays often come up and induce civil aviation safety risk simultaneously. Based on flight delays, the random characteristics of civil aviation safety risk are analyzed. Flight delays have been deemed to a potential safety hazard. The change rules and characteristics of civil aviation safety risk based on flight delays have been analyzed. Bayesian networks (BN) have been used to build ...

  2. A neural based intelligent flight control system for the NASA F-15 flight research aircraft

    Science.gov (United States)

    Urnes, James M.; Hoy, Stephen E.; Ladage, Robert N.; Stewart, James

    1993-01-01

    A flight control concept that can identify aircraft stability properties and continually optimize the aircraft flying qualities has been developed by McDonnell Aircraft Company under a contract with the NASA-Dryden Flight Research Facility. This flight concept, termed the Intelligent Flight Control System, utilizes Neural Network technology to identify the host aircraft stability and control properties during flight, and use this information to design on-line the control system feedback gains to provide continuous optimum flight response. This self-repairing capability can provide high performance flight maneuvering response throughout large flight envelopes, such as needed for the National Aerospace Plane. Moreover, achieving this response early in the vehicle's development schedule will save cost.

  3. Flight capacity of Bactrocera dorsalis (Diptera: Tephritidae) adult females based on flight mill studies and flight muscle ultrastructure.

    Science.gov (United States)

    Chen, Min; Chen, Peng; Ye, Hui; Yuan, Ruiling; Wang, Xiaowei; Xu, Jin

    2015-01-01

    The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is considered a major economic threat in many regions worldwide. To better comprehend flight capacity of B. dorsalis and its physiological basis, a computer-monitored flight mill was used to study flight capacity of B. dorsalis adult females of various ages, and the changes of its flight muscle ultrastructures were studied by transmission electron microscopy. The flight capacity (both speed and distance) changed significantly with age of B. dorsalis female adults, peaking at about 15 d; the myofibril diameter of the flight muscle of test insects at 15-d old was the longest, up to 1.56 µm, the sarcomere length at 15-d old was the shortest, averaging at 1.37 µm, volume content of mitochondria of flight muscle at 15-d old reached the peak, it was 32.64%. This study provides the important scientific data for better revealing long-distance movement mechanism of B. dorsalis. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  4. Motion planning for autonomous vehicle based on radial basis function neural network in unstructured environment.

    Science.gov (United States)

    Chen, Jiajia; Zhao, Pan; Liang, Huawei; Mei, Tao

    2014-09-18

    The autonomous vehicle is an automated system equipped with features like environment perception, decision-making, motion planning, and control and execution technology. Navigating in an unstructured and complex environment is a huge challenge for autonomous vehicles, due to the irregular shape of road, the requirement of real-time planning, and the nonholonomic constraints of vehicle. This paper presents a motion planning method, based on the Radial Basis Function (RBF) neural network, to guide the autonomous vehicle in unstructured environments. The proposed algorithm extracts the drivable region from the perception grid map based on the global path, which is available in the road network. The sample points are randomly selected in the drivable region, and a gradient descent method is used to train the RBF network. The parameters of the motion-planning algorithm are verified through the simulation and experiment. It is observed that the proposed approach produces a flexible, smooth, and safe path that can fit any road shape. The method is implemented on autonomous vehicle and verified against many outdoor scenes; furthermore, a comparison of proposed method with the existing well-known Rapidly-exploring Random Tree (RRT) method is presented. The experimental results show that the proposed method is highly effective in planning the vehicle path and offers better motion quality.

  5. Model Based Analysis and Test Generation for Flight Software

    Science.gov (United States)

    Pasareanu, Corina S.; Schumann, Johann M.; Mehlitz, Peter C.; Lowry, Mike R.; Karsai, Gabor; Nine, Harmon; Neema, Sandeep

    2009-01-01

    We describe a framework for model-based analysis and test case generation in the context of a heterogeneous model-based development paradigm that uses and combines Math- Works and UML 2.0 models and the associated code generation tools. This paradigm poses novel challenges to analysis and test case generation that, to the best of our knowledge, have not been addressed before. The framework is based on a common intermediate representation for different modeling formalisms and leverages and extends model checking and symbolic execution tools for model analysis and test case generation, respectively. We discuss the application of our framework to software models for a NASA flight mission.

  6. Digital virtual flight testing and evaluation method for flight characteristics airworthiness compliance of civil aircraft based on HQRM

    Directory of Open Access Journals (Sweden)

    Fan Liu

    2015-02-01

    Full Text Available In order to incorporate airworthiness requirements for flight characteristics into the entire development cycle of electronic flight control system (EFCS equipped civil aircraft, digital virtual flight testing and evaluation method based on handling qualities rating method (HQRM is proposed. First, according to HQRM, flight characteristics airworthiness requirements of civil aircraft in EFCS failure states are determined. On this basis, digital virtual flight testing model, comprising flight task digitized model, pilot controlling model, aircraft motion and atmospheric turbulence model, is used to simulate the realistic process of a pilot controlling an airplane to perform assigned flight tasks. According to the simulation results, flight characteristics airworthiness compliance of the airplane can be evaluated relying on the relevant regulations for handling qualities (HQ rating. Finally, this method is applied to a type of passenger airplane in a typical EFCS failure state, and preliminary conclusions concerning airworthiness compliance are derived quickly. The research results of this manuscript can provide important theoretical reference for EFCS design and actual airworthiness compliance verification of civil aircraft.

  7. Digital virtual flight testing and evaluation method for flight characteristics airworthiness compliance of civil aircraft based on HQRM

    Institute of Scientific and Technical Information of China (English)

    Liu Fan; Wang Lixin; Tan Xiangsheng

    2015-01-01

    In order to incorporate airworthiness requirements for flight characteristics into the entire development cycle of electronic flight control system (EFCS) equipped civil aircraft, digital virtual flight testing and evaluation method based on handling qualities rating method (HQRM) is proposed. First, according to HQRM, flight characteristics airworthiness requirements of civil aircraft in EFCS failure states are determined. On this basis, digital virtual flight testing model, comprising flight task digitized model, pilot controlling model, aircraft motion and atmospheric tur-bulence model, is used to simulate the realistic process of a pilot controlling an airplane to perform assigned flight tasks. According to the simulation results, flight characteristics airworthiness com-pliance of the airplane can be evaluated relying on the relevant regulations for handling qualities (HQ) rating. Finally, this method is applied to a type of passenger airplane in a typical EFCS failure state, and preliminary conclusions concerning airworthiness compliance are derived quickly. The research results of this manuscript can provide important theoretical reference for EFCS design and actual airworthiness compliance verification of civil aircraft.

  8. Covariance analysis of differential drag-based satellite cluster flight

    Science.gov (United States)

    Ben-Yaacov, Ohad; Ivantsov, Anatoly; Gurfil, Pini

    2016-06-01

    One possibility for satellite cluster flight is to control relative distances using differential drag. The idea is to increase or decrease the drag acceleration on each satellite by changing its attitude, and use the resulting small differential acceleration as a controller. The most significant advantage of the differential drag concept is that it enables cluster flight without consuming fuel. However, any drag-based control algorithm must cope with significant aerodynamical and mechanical uncertainties. The goal of the current paper is to develop a method for examination of the differential drag-based cluster flight performance in the presence of noise and uncertainties. In particular, the differential drag control law is examined under measurement noise, drag uncertainties, and initial condition-related uncertainties. The method used for uncertainty quantification is the Linear Covariance Analysis, which enables us to propagate the augmented state and filter covariance without propagating the state itself. Validation using a Monte-Carlo simulation is provided. The results show that all uncertainties have relatively small effect on the inter-satellite distance, even in the long term, which validates the robustness of the used differential drag controller.

  9. Identification and standardization of maneuvers based upon operational flight data

    Institute of Scientific and Technical Information of China (English)

    Wang Yongjun; Dong Jiang; Liu Xiaodong; Zhang Lixin

    2015-01-01

    To find a way of loads analysis from operational flight data for advanced aircraft, maneuver identification and standardization jobs are conducted in this paper. For thousands of sor-ties from one aircraft, after studying the flight attitude when performing actions, the start and end time of the maneuvers can be determined. According to those time points, various types of maneu-vers during the flight are extracted in the form of multi-parameters time histories. By analyzing the numerical range and curve shape of those parameters, a characteristic data library is established to model all types of maneuvers. Based on this library, a computer procedure using pattern-recogni-tion theory is programmed to conduct automatic maneuver identification with high accuracy. In that way, operational loads are classified according to maneuver type. For a group of identified maneuvers of the same type, after the processes of time normalization, trace shifting, as well as aver-aging and smoothing, the idealization standard time history of each maneuver type is established. Finally, the typical load statuses are determined successfully based on standard maneuvers. The proposed method of maneuver identification and standardization is able to derive operational loads effectively, and might be applied to monitoring loads in Individual Aircraft Tracking Program (IATP).

  10. Autonomous operations through onboard artificial intelligence

    Science.gov (United States)

    Sherwood, R. L.; Chien, S.; Castano, R.; Rabideau, G.

    2002-01-01

    The Autonomous Sciencecraft Experiment (ASE) will fly onboard the Air Force TechSat 21 constellation of three spacecraft scheduled for launch in 2006. ASE uses onboard continuous planning, robust task and goal-based execution, model-based mode identification and reconfiguration, and onboard machine learning and pattern recognition to radically increase science return by enabling intelligent downlink selection and autonomous retargeting. Demonstration of these capabilities in a flight environment will open up tremendous new opportunities in planetary science, space physics, and earth science that would be unreachable without this technology.

  11. Current Situation of English Major Students’ Web-based Autonomous English Learning

    Institute of Scientific and Technical Information of China (English)

    李新华

    2015-01-01

    Through an interview of three English major students and a fi eld observation,the study explores English major students’web-based autonomous English learning situation and the problems on their way.The findings show that web-based English materials are most helpful to speaking and listening,and that students’insufficient information retrieval skill is the main problem on their way.

  12. An integrated Constraint-based, power Aware control system for Autonomous rover Mission operations

    OpenAIRE

    Diaz, Daniel; Rodriguez-Moreno, Maria Dolores; Cesta, Amedeo; Oddi, Angelo; Rasconi, Riccardo

    2012-01-01

    This paper aims at describing an integrated power-aware, model-based autonomous control architecture for planetary rover-based mission operations synthesized in the context of a Ph.D. program on the topic "Autonomy for Interplanetary missions" funded and supported by ESA. The proposed controller implements a single Sense-Act-Plan (SPA) closed-execution loop to safely command the robot activities considered in the context of a specific key mission scenario. Both highly decision making capabili...

  13. Decentralized Autonomous-Agent-Based Infrastructure for Agile Multiparallel Manufacturing

    NARCIS (Netherlands)

    Ing. Erik Puik; Leo van Moergestel; John-Jules Meyer; Daniël Telgen

    2011-01-01

    This paper describes an agent-based software infrastructure for agile industrial production. This production is done on special devices called equiplets. A grid of these equiplets connected by a fast network is capable of producing a variety of different products in parallel. The multi-agent-based

  14. A learning-based autonomous driver: emulate human driver's intelligence in low-speed car following

    Science.gov (United States)

    Wei, Junqing; Dolan, John M.; Litkouhi, Bakhtiar

    2010-04-01

    In this paper, an offline learning mechanism based on the genetic algorithm is proposed for autonomous vehicles to emulate human driver behaviors. The autonomous driving ability is implemented based on a Prediction- and Cost function-Based algorithm (PCB). PCB is designed to emulate a human driver's decision process, which is modeled as traffic scenario prediction and evaluation. This paper focuses on using a learning algorithm to optimize PCB with very limited training data, so that PCB can have the ability to predict and evaluate traffic scenarios similarly to human drivers. 80 seconds of human driving data was collected in low-speed (car-following scenarios. In the low-speed car-following tests, PCB was able to perform more human-like carfollowing after learning. A more general 120 kilometer-long simulation showed that PCB performs robustly even in scenarios that are not part of the training set.

  15. Efficient Kinect Sensor-Based Reactive Path Planning Method for Autonomous Mobile Robots in Dynamic Environments

    Energy Technology Data Exchange (ETDEWEB)

    Tuvshinjargal, Doopalam; Lee, Deok Jin [Kunsan National University, Gunsan (Korea, Republic of)

    2015-06-15

    In this paper, an efficient dynamic reactive motion planning method for an autonomous vehicle in a dynamic environment is proposed. The purpose of the proposed method is to improve the robustness of autonomous robot motion planning capabilities within dynamic, uncertain environments by integrating a virtual plane-based reactive motion planning technique with a sensor fusion-based obstacle detection approach. The dynamic reactive motion planning method assumes a local observer in the virtual plane, which allows the effective transformation of complex dynamic planning problems into simple stationary ones proving the speed and orientation information between the robot and obstacles. In addition, the sensor fusion-based obstacle detection technique allows the pose estimation of moving obstacles using a Kinect sensor and sonar sensors, thus improving the accuracy and robustness of the reactive motion planning approach. The performance of the proposed method was demonstrated through not only simulation studies but also field experiments using multiple moving obstacles in hostile dynamic environments.

  16. GA-Based Autonomous Design of Robust Fast and Precise Positioning Considering Machine Stand Vibration Suppression

    Science.gov (United States)

    Ito, Kazuaki; Nagata, Ryo; Iwasaki, Makoto; Matsui, Nobuyuki

    This paper presents a novel Genetic Algorithm (GA)-based autonomous compensator design and position command shaping considering the stand vibration suppression for the fast-response and high-precision positioning of mechatronic systems. The positioning system is mainly composed of a robust 2-degrees-of-freedom (2DOF) controller based on the coprime factorization description. The feedback compensator based on H∞ design framework in the 2DOF controller ensures the robustness against the variations of resonant vibration mode. The feedforward compensator and position command, on the other hand, can be autonomously designed by the optimization capability of GA, in order to achieve the desired positioning performance and to suppress the machine stand vibration. The effectiveness of the proposed optimal design has been verified by experiments using a table drive system with ball screw.

  17. Automated Search-Based Robustness Testing for Autonomous Vehicle Software

    National Research Council Canada - National Science Library

    Betts, Kevin M; Petty, Mikel D

    2016-01-01

    .... Search-based testing techniques were used to automatically generate test cases, consisting of initial conditions and fault sequences, intended to challenge the control software more than test cases...

  18. Autonomic Resource Provisioning for Cloud-Based Software

    DEFF Research Database (Denmark)

    Jamshidi, Pooyan; Ahmad, Aakash; Pahl, Claus

    2014-01-01

    and expertise. Furthermore, existing approaches do not explicitly deal with uncertainty in cloud-based software, where noise, unexpected events and workload fluctuations are common. This paper exploits fuzzy logic to enable qualitative specification of elasticity rules for cloud-based software. In addition......Elasticity endows a software system with the ability to maintain optimal user experience by automatically acquiring and releasing resources, while paying only for what they require. The mechanism for automatically adding or removing resources on the fly is referred to as auto-scaling. The state......, this paper discusses a control theoretical approach using type-2 fuzzy logic systems to reason about elasticity under uncertainties. We conduct several experiments to demonstrate that cloud-based software enhanced with such elasticity controller can robustly handle unexpected spikes in the workloads...

  19. Using Model-Based Reasoning for Autonomous Instrument Operation - Lessons Learned From IMAGE/LENA

    Science.gov (United States)

    Johnson, Michael A.; Rilee, Michael L.; Truszkowski, Walt; Bailin, Sidney C.

    2001-01-01

    Model-based reasoning has been applied as an autonomous control strategy on the Low Energy Neutral Atom (LENA) instrument currently flying on board the Imager for Magnetosphere-to-Aurora Global Exploration (IMAGE) spacecraft. Explicit models of instrument subsystem responses have been constructed and are used to dynamically adapt the instrument to the spacecraft's environment. These functions are cast as part of a Virtual Principal Investigator (VPI) that autonomously monitors and controls the instrument. In the VPI's current implementation, LENA's command uplink volume has been decreased significantly from its previous volume; typically, no uplinks are required for operations. This work demonstrates that a model-based approach can be used to enhance science instrument effectiveness. The components of LENA are common in space science instrumentation, and lessons learned by modeling this system may be applied to other instruments. Future work involves the extension of these methods to cover more aspects of LENA operation and the generalization to other space science instrumentation.

  20. Bilateral Teleoperation Method Using an Autonomous Control Based on Information on Contact Environment

    Science.gov (United States)

    Taguchi, Keiichi; Ohnishi, Kouhei

    In procedures that involve remote control, such as remote surgery, it is necessary to operate a robot in a remote location in a sensitive environment; the treatment of internal organs is an example of such a procedure. In this paper, we propose a method for autonomous hazard avoidance control that is based on information on the contact environment. The proposed method involves the use of bilateral control. During safe operations, systems are controlled by bilateral control. During dangerous operations, a slave system is controlled autonomously so as to avoid dangerous operations. In order to determine the degree of operation risk, fuzzy set theory is applied to the force exerted on the environment. Further, variable compliance control based on the force exerted on the environment is utilized to avoid the risk. The effectiveness of the proposed method is confirmed by experimental results.

  1. Autonomous landing of a helicopter UAV with a ground-based multisensory fusion system

    Science.gov (United States)

    Zhou, Dianle; Zhong, Zhiwei; Zhang, Daibing; Shen, Lincheng; Yan, Chengping

    2015-02-01

    In this study, this paper focus on the vision-based autonomous helicopter unmanned aerial vehicle (UAV) landing problems. This paper proposed a multisensory fusion to autonomous landing of an UAV. The systems include an infrared camera, an Ultra-wideband radar that measure distance between UAV and Ground-Based system, an PAN-Tilt Unit (PTU). In order to identify all weather UAV targets, we use infrared cameras. To reduce the complexity of the stereovision or one-cameral calculating the target of three-dimensional coordinates, using the ultra-wideband radar distance module provides visual depth information, real-time Image-PTU tracking UAV and calculate the UAV threedimensional coordinates. Compared to the DGPS, the test results show that the paper is effectiveness and robustness.

  2. Autonomous facial recognition system inspired by human visual system based logarithmical image visualization technique

    Science.gov (United States)

    Wan, Qianwen; Panetta, Karen; Agaian, Sos

    2017-05-01

    Autonomous facial recognition system is widely used in real-life applications, such as homeland border security, law enforcement identification and authentication, and video-based surveillance analysis. Issues like low image quality, non-uniform illumination as well as variations in poses and facial expressions can impair the performance of recognition systems. To address the non-uniform illumination challenge, we present a novel robust autonomous facial recognition system inspired by the human visual system based, so called, logarithmical image visualization technique. In this paper, the proposed method, for the first time, utilizes the logarithmical image visualization technique coupled with the local binary pattern to perform discriminative feature extraction for facial recognition system. The Yale database, the Yale-B database and the ATT database are used for computer simulation accuracy and efficiency testing. The extensive computer simulation demonstrates the method's efficiency, accuracy, and robustness of illumination invariance for facial recognition.

  3. Anthropocentric-based robotic and autonomous systems: assessment for new organisational options

    OpenAIRE

    Moniz, António

    2010-01-01

    Text based on the paper presented at the Conference "Autonomous systems: inter-relations of technical and societal issues" held at Monte de Caparica (Portugal), Universidade Nova de Lisboa, November, 5th and 6th 2009 and organized by IET-Research Centre on Enterprise and Work Innovation Research activities at European level on the concept of new working environments offers considerable attention to the challenges of the increased competencies of people working together with automated techn...

  4. A feature matching and fusion-based positive obstacle detection algorithm for field autonomous land vehicles

    Directory of Open Access Journals (Sweden)

    Tao Wu

    2017-03-01

    Full Text Available Positive obstacles will cause damage to field robotics during traveling in field. Field autonomous land vehicle is a typical field robotic. This article presents a feature matching and fusion-based algorithm to detect obstacles using LiDARs for field autonomous land vehicles. There are three main contributions: (1 A novel setup method of compact LiDAR is introduced. This method improved the LiDAR data density and reduced the blind region of the LiDAR sensor. (2 A mathematical model is deduced under this new setup method. The ideal scan line is generated by using the deduced mathematical model. (3 Based on the proposed mathematical model, a feature matching and fusion (FMAF-based algorithm is presented in this article, which is employed to detect obstacles. Experimental results show that the performance of the proposed algorithm is robust and stable, and the computing time is reduced by an order of two magnitudes by comparing with other exited algorithms. This algorithm has been perfectly applied to our autonomous land vehicle, which has won the champion in the challenge of Chinese “Overcome Danger 2014” ground unmanned vehicle.

  5. Autonomous Landing and Ingress of Micro-Air-Vehicles in Urban Environments Based on Monocular Vision

    Science.gov (United States)

    Brockers, Roland; Bouffard, Patrick; Ma, Jeremy; Matthies, Larry; Tomlin, Claire

    2011-01-01

    Unmanned micro air vehicles (MAVs) will play an important role in future reconnaissance and search and rescue applications. In order to conduct persistent surveillance and to conserve energy, MAVs need the ability to land, and they need the ability to enter (ingress) buildings and other structures to conduct reconnaissance. To be safe and practical under a wide range of environmental conditions, landing and ingress maneuvers must be autonomous, using real-time, onboard sensor feedback. To address these key behaviors, we present a novel method for vision-based autonomous MAV landing and ingress using a single camera for two urban scenarios: landing on an elevated surface, representative of a rooftop, and ingress through a rectangular opening, representative of a door or window. Real-world scenarios will not include special navigation markers, so we rely on tracking arbitrary scene features; however, we do currently exploit planarity of the scene. Our vision system uses a planar homography decomposition to detect navigation targets and to produce approach waypoints as inputs to the vehicle control algorithm. Scene perception, planning, and control run onboard in real-time; at present we obtain aircraft position knowledge from an external motion capture system, but we expect to replace this in the near future with a fully self-contained, onboard, vision-aided state estimation algorithm. We demonstrate autonomous vision-based landing and ingress target detection with two different quadrotor MAV platforms. To our knowledge, this is the first demonstration of onboard, vision-based autonomous landing and ingress algorithms that do not use special purpose scene markers to identify the destination.

  6. Autonomous sensor-based dual-arm satellite grappling

    Science.gov (United States)

    Wilcox, Brian; Tso, Kam; Litwin, Todd; Hayati, Samad; Bon, Bruce

    1989-01-01

    Dual-arm satellite grappling involves the integration of technologies developed in the Sensing and Perception (S&P) Subsystem for object acquisition and tracking, and the Manipulator Control and Mechanization (MCM) Subsystem for dual-arm control. S&P acquires and tracks the position, orientation, velocity, and angular velocity of a slowly spinning satellite, and sends tracking data to the MCM subsystem. MCM grapples the satellite and brings it to rest, controlling the arms so that no excessive forces or torques are exerted on the satellite or arms. A 350-pound satellite mockup which can spin freely on a gimbal for several minutes, closely simulating the dynamics of a real satellite is demonstrated. The satellite mockup is fitted with a panel under which may be mounted various elements such as line replacement modules and electrical connectors that will be used to demonstrate servicing tasks once the satellite is docked. The subsystems are housed in three MicroVAX II microcomputers. The hardware of the S&P Subsystem includes CCD cameras, video digitizers, frame buffers, IMFEX (a custom pipelined video processor), a time-code generator with millisecond precision, and a MicroVAX II computer. Its software is written in Pascal and is based on a locally written vision software library. The hardware of the MCM Subsystem includes PUMA 560 robot arms, Lord force/torque sensors, two MicroVAX II computers, and unimation pneumatic parallel grippers. Its software is written in C, and is based on a robot language called RCCL. The two subsystems are described and test results on the grappling of the satellite mockup with rotational rates of up to 2 rpm are provided.

  7. Magnetic Bead Based Immunoassay for Autonomous Detection of Toxins

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Y; Hara, C A; Knize, M G; Hwang, M H; Venkatesteswaran, K S; Wheeler, E K; Bell, P M; Renzi, R F; Fruetel, J A; Bailey, C G

    2008-05-01

    As a step towards toward the development of a rapid, reliable analyzer for bioagents in the environment, we are developing an automated system for the simultaneous detection of a group of select agents and toxins. To detect toxins, we modified and automated an antibody-based approach previously developed for manual medical diagnostics that uses fluorescent eTag{trademark} reporter molecules and is suitable for highly multiplexed assays. Detection is based on two antibodies binding simultaneously to a single antigen, one of which is labeled with biotin while the other is conjugated to a fluorescent eTag{trademark} through a cleavable linkage. Aqueous samples are incubated with the mixture of antibodies along with streptavidin-coated magnetic beads coupled to a photo-activatable porphyrin complex. In the presence of antigen, a molecular complex is formed where the cleavable linkage is held in proximity to the photoactivable group. Upon excitation at 680 nm, free radicals are generated, which diffuse and cleave the linkage, releasing the eTags{trademark}. Released eTags{trademark} are analyzed using capillary gel electrophoresis with laser-induced fluorescence detection. Limits of detection for ovalbumin and botulinum toxoid individually were 4 ng/mL (or 80 pg) and 16 ng/mL (or 320 pg), respectively, using the manual assay. In addition, we demonstrated the use of pairs of antibodies from different sources in a single assay to decrease the rate of false positives. Automation of the assay was demonstrated on a flow-through format with higher LODs of 125 ng/mL (or 2.5 ng) each of a mixture of ovalbumin and botulinum toxoid. This versatile assay can be easily modified with the appropriate antibodies to detect a wide range of toxins and other proteins.

  8. An LMI-based decoupling control for electromagnetic formation flight

    Directory of Open Access Journals (Sweden)

    Huang Xianlin

    2015-04-01

    Full Text Available Electromagnetic formation flight (EMFF leverages electromagnetic force to control the relative position of satellites. EMFF offers a promising alternative to traditional propellant-based spacecraft flight formation. This novel strategy is very attractive since it does not consume fuel. Due to the highly coupled nonlinearity of electromagnetic force, it is difficult to individually design a controller for one satellite without considering others, which poses challenges to communications. This paper is devoted to decoupling control of EMFF, including regulations, constraints and controller design. A learning-based adaptive sliding mode decoupling controller is analyzed to illustrate the problem of existing results, and input rate saturation is introduced to guarantee the validity of frequency division technique. Through transformation, the imposed input rate saturation is converted to state and input constraints. A linear matrix inequalities (LMI-based robust optimal control method can then be used and improved to solve the transformed problem. Simulation results are presented to demonstrate the effectiveness of the proposed decoupling control.

  9. An Autonomous Underwater Recorder Based on a Single Board Computer.

    Science.gov (United States)

    Caldas-Morgan, Manuel; Alvarez-Rosario, Alexander; Rodrigues Padovese, Linilson

    2015-01-01

    As industrial activities continue to grow on the Brazilian coast, underwater sound measurements are becoming of great scientific importance as they are essential to evaluate the impact of these activities on local ecosystems. In this context, the use of commercial underwater recorders is not always the most feasible alternative, due to their high cost and lack of flexibility. Design and construction of more affordable alternatives from scratch can become complex because it requires profound knowledge in areas such as electronics and low-level programming. With the aim of providing a solution; a well succeeded model of a highly flexible, low-cost alternative to commercial recorders was built based on a Raspberry Pi single board computer. A properly working prototype was assembled and it demonstrated adequate performance levels in all tested situations. The prototype was equipped with a power management module which was thoroughly evaluated. It is estimated that it will allow for great battery savings on long-term scheduled recordings. The underwater recording device was successfully deployed at selected locations along the Brazilian coast, where it adequately recorded animal and manmade acoustic events, among others. Although power consumption may not be as efficient as that of commercial and/or micro-processed solutions, the advantage offered by the proposed device is its high customizability, lower development time and inherently, its cost.

  10. An Autonomous Underwater Recorder Based on a Single Board Computer.

    Directory of Open Access Journals (Sweden)

    Manuel Caldas-Morgan

    Full Text Available As industrial activities continue to grow on the Brazilian coast, underwater sound measurements are becoming of great scientific importance as they are essential to evaluate the impact of these activities on local ecosystems. In this context, the use of commercial underwater recorders is not always the most feasible alternative, due to their high cost and lack of flexibility. Design and construction of more affordable alternatives from scratch can become complex because it requires profound knowledge in areas such as electronics and low-level programming. With the aim of providing a solution; a well succeeded model of a highly flexible, low-cost alternative to commercial recorders was built based on a Raspberry Pi single board computer. A properly working prototype was assembled and it demonstrated adequate performance levels in all tested situations. The prototype was equipped with a power management module which was thoroughly evaluated. It is estimated that it will allow for great battery savings on long-term scheduled recordings. The underwater recording device was successfully deployed at selected locations along the Brazilian coast, where it adequately recorded animal and manmade acoustic events, among others. Although power consumption may not be as efficient as that of commercial and/or micro-processed solutions, the advantage offered by the proposed device is its high customizability, lower development time and inherently, its cost.

  11. Towards an Autonomous Vision-Based Unmanned Aerial System against Wildlife Poachers

    Directory of Open Access Journals (Sweden)

    Miguel A. Olivares-Mendez

    2015-12-01

    Full Text Available Poaching is an illegal activity that remains out of control in many countries. Based on the 2014 report of the United Nations and Interpol, the illegal trade of global wildlife and natural resources amounts to nearly $ 213 billion every year, which is even helping to fund armed conflicts. Poaching activities around the world are further pushing many animal species on the brink of extinction. Unfortunately, the traditional methods to fight against poachers are not enough, hence the new demands for more efficient approaches. In this context, the use of new technologies on sensors and algorithms, as well as aerial platforms is crucial to face the high increase of poaching activities in the last few years. Our work is focused on the use of vision sensors on UAVs for the detection and tracking of animals and poachers, as well as the use of such sensors to control quadrotors during autonomous vehicle following and autonomous landing.

  12. Virtual Reality-based Telesurgery via Teleprogramming Scheme Combined with Semi-autonomous Control.

    Science.gov (United States)

    Zhijiang, Du; Zhiheng, Jia; Minxiu, Kong

    2005-01-01

    Telesurgery systems have long been suffering variable and unpredictable Internet commutation time delay, operation fatigue, and other drawbacks. Based on virtual reality technology, a teleprogramming scheme combined with semi-autonomous control is introduced to guarantee the robustness and efficiency of teleoperation of HIT-RAOS, a robot-assisted orthopedic surgery system. In this system, without considering time delay, the operator can just interact with virtual environment which provides real-time 3D vision, stereophonic sound, and tactile and force feedback imitated by a parallel master manipulator. And several tasks can be managed simultaneously via semi-autonomous control. Finally, the method is experimentally demonstrated on an experiment of locking of intramedullary nails, and is shown to effectively provide stability and performances.

  13. Towards an Autonomous Vision-Based Unmanned Aerial System against Wildlife Poachers

    Science.gov (United States)

    Olivares-Mendez, Miguel A.; Fu, Changhong; Ludivig, Philippe; Bissyandé, Tegawendé F.; Kannan, Somasundar; Zurad, Maciej; Annaiyan, Arun; Voos, Holger; Campoy, Pascual

    2015-01-01

    Poaching is an illegal activity that remains out of control in many countries. Based on the 2014 report of the United Nations and Interpol, the illegal trade of global wildlife and natural resources amounts to nearly $213 billion every year, which is even helping to fund armed conflicts. Poaching activities around the world are further pushing many animal species on the brink of extinction. Unfortunately, the traditional methods to fight against poachers are not enough, hence the new demands for more efficient approaches. In this context, the use of new technologies on sensors and algorithms, as well as aerial platforms is crucial to face the high increase of poaching activities in the last few years. Our work is focused on the use of vision sensors on UAVs for the detection and tracking of animals and poachers, as well as the use of such sensors to control quadrotors during autonomous vehicle following and autonomous landing. PMID:26703597

  14. TractorEYE: Vision-based Real-time Detection for Autonomous Vehicles in Agriculture

    DEFF Research Database (Denmark)

    Christiansen, Peter

    2017-01-01

    and algorithms that have been demonstrated in an end-to-end real-time detection system. The contributions of this thesis have demonstrated, addressed and solved critical issues to utilize camera-based perception systems that are essential to make autonomous vehicles in agriculture a reality....... for autonomous vehicles in agriculture. The multi-sensor system consists of three hardware synchronized and registered sensors (stereo camera, thermal camera and multi-beam lidar) mounted on/in a ruggedized and water-resistant casing. Algorithms have been developed to run a total of six detection algorithms...... (four for rgb camera, one for thermal camera and one for a Multi-beam lidar) and fuse detection information in a common format using either 3D positions or Inverse Sensor Models. A GPU powered computational platform is able to run detection algorithms online. For the rgb camera, a deep learning...

  15. Towards an Autonomous Vision-Based Unmanned Aerial System against Wildlife Poachers.

    Science.gov (United States)

    Olivares-Mendez, Miguel A; Fu, Changhong; Ludivig, Philippe; Bissyandé, Tegawendé F; Kannan, Somasundar; Zurad, Maciej; Annaiyan, Arun; Voos, Holger; Campoy, Pascual

    2015-12-12

    Poaching is an illegal activity that remains out of control in many countries. Based on the 2014 report of the United Nations and Interpol, the illegal trade of global wildlife and natural resources amounts to nearly $ 213 billion every year, which is even helping to fund armed conflicts. Poaching activities around the world are further pushing many animal species on the brink of extinction. Unfortunately, the traditional methods to fight against poachers are not enough, hence the new demands for more efficient approaches. In this context, the use of new technologies on sensors and algorithms, as well as aerial platforms is crucial to face the high increase of poaching activities in the last few years. Our work is focused on the use of vision sensors on UAVs for the detection and tracking of animals and poachers, as well as the use of such sensors to control quadrotors during autonomous vehicle following and autonomous landing.

  16. Test of a vision-based autonomous space station robotic task

    Science.gov (United States)

    Castellano, Anthony R.; Hwang, Vincent S. S.; Stoney, William E.

    1991-02-01

    An area of increasing interest in Al Robotics and Computer Vision is integrating techniques from these fields to the problem of controlling autonomous systems. Space-based systems such as NASA''s robotic assembly of Orbital Replacement Units (ORU''s) provide a complex realistic domain for this integration research. In this paper we report on current MITRE research in the use of situated control for autonomous robotic assembly of ORUs. A wrist-mounted camera is used to acquire the pose of ORU''s. An on-line control module uses the pose data to refine the on-going robot actions so that the planned task can be executed both safely and robustly. Experimental results on a Cincinnati Milacron T3 Industrial robot at Goddard Space Right Center (GSFC) Intelligent Robotic Laboratory will be included.

  17. Emergence of Cooperative Behavior based on Learning and Evolution in Collective Autonomous Mobile Robots

    Energy Technology Data Exchange (ETDEWEB)

    Jun, H.B.; Sim, K.B. [Chungang University, Seoul (Korea, Republic of)

    1998-12-01

    In this paper, we propose a behavior learning algorithm of the collective autonomous mobile robots based on the reinforcement learning and conditional evolution. The cooperative behavior is a high level phenomenon observed in the society of social animals and, recently the emergence of cooperative behavior in collective autonomous mobile robots becomes an interesting field in artificial life. In our system each robot with simple behavior strategies can adapt to its environment by means of the reinforcement learning. The internal reinforcement signal for the reinforcement learning is generated by fuzzy interference engine, and dynamic recurrent neural networks are used as an action generation module. We propose conditional evolution for the emergence of cooperative behavior. The evolutionary conditions are spatio-temporal limitations to the occurrence of genetic operations. We show the validity of the proposed learning and evolutionary algorithm through several computer simulations. (author). 22 refs., 9 figs.

  18. Design and Implementation an Autonomous Humanoid Robot Based on Fuzzy Rule-Based Motion Controller

    Directory of Open Access Journals (Sweden)

    Mohsen Taheri

    2010-04-01

    Full Text Available Research on humanoid robotics in Mechatronics and Automation Laboratory, Electrical and Computer Engineering, Islamic Azad University Khorasgan branch (Isfahan of Iran was started at
    the beginning of this decade. Various research prototypes for humanoid robots have been designed and are going through evolution over these years. This paper describes the hardware and software design of the kid size humanoid robot systems of the PERSIA Team in 2009. The robot has 20 actuated degrees of freedom based on Hitec HSR898. In this paper we have tried to focus on areas such as mechanical structure, Image processing unit, robot controller, Robot AI and behavior
    learning. In 2009, our developments for the Kid size humanoid robot include: (1 the design and construction of our new humanoid robots (2 the design and construction of a new hardware and software controller to be used in our robots. The project is described in two main parts: Hardware and Software. The software is developed a robot application which consists walking controller, autonomous motion robot, self localization base on vision and Particle Filter, local AI, Trajectory Planning, Motion Controller and Network. The hardware consists of the mechanical structure and the driver circuit board. Each robot is able to walk, fast walk, pass, kick and dribble when it catches
    the ball. These humanoids have been successfully participating in various robotic soccer competitions. This project is still in progress and some new interesting methods are described in the current report.

  19. Assessment of individual adaptation to microgravity during long term space flight based on stepwise discriminant analysis of heart rate variability parameters

    Science.gov (United States)

    Baevsky, Roman M.; Chernikova, Anna G.; Funtova, Irina I.; Tank, Jens

    2011-12-01

    Optimization of the cardiovascular system under conditions of long term space flight is provided by individual changes of autonomic cardiovascular control. Heart rate variability (HRV) analysis is an easy to use method under these extreme conditions. We tested the hypothesis that individual HRV analysis provides important information for crew health monitoring. HRV data from 14 Russian cosmonauts measured during long term space flights are presented (two times before and after flight, monthly in flight). HRV characteristics in the time and in the frequency domain were calculated. Predefined discriminant function equations obtained in reference groups (L1=-0.112*HR-1.006*SI-0.047*pNN50-0.086*HF; L2=0.140*HR-0.165*SI-1.293*pNN50+0.623*HF) were used to define four functional states. (1) Physiological normal, (2) prenosological, (3) premorbid and (4) pathological. Geometric mean values for the ISS cosmonauts based on L1 and L2 remained within normal ranges. A shift from the physiological normal state to the prenosological functional state during space flight was detected. The functional state assessed by HRV improved during space flight if compared to pre-flight and early post-flight functional states. Analysis of individual cosmonauts showed distinct patterns depending on the pre-flight functional state. Using the developed classification a transition process from the state of physiological normal into a prenosological state or premorbid state during different stages of space flight can be detected for individual Russian cosmonauts. Our approach to an estimation of HR regulatory pattern can be useful for prognostic purposes.

  20. Differentiation of Internet addiction risk level based on autonomic nervous responses: the Internet-addiction hypothesis of autonomic activity.

    Science.gov (United States)

    Lu, Dong Wei; Wang, Jenn Wu; Huang, Andrew Chih Wei

    2010-08-01

    How high-risk Internet addiction (IA) abusers respond to different autonomic nervous activities compared with low-risk subjects may be a critical research goal with prevention and treatment implications. The aim of the present study was to address this issue by observing differences between high- and low-risk IA abusers in four physiological assessments when surfing the Internet: blood volume pulse (BVP), skin conductance (SC), peripheral temperature (PTEMP), and respiratory response (RESPR). Forty-two male and ten female participants aged 18-24 years were screened with the Chen Internet Addiction Scale (CIAS, 2003), and then separated into high- and low-risk IA groups. Using psychophysiology equipment, participants encountered a 3-minute adaptation period followed by a 6-minute testing period for surfing the Internet on baseline and testing phases. The present results indicate that: (a) the CIAS scores were positively and negatively correlated with the RESPR and the PTEMP; (b) the PTEMP and RESPR of high-risk IA abusers were respectively weaker and stronger than those of low-risk IA abusers; the BVP and SC of high-risk IA abusers were respectively augmented and decreased relative to low-risk IA abusers. Thus we suggest that four autonomic responses may be differentially sensitive to abusers' potency in terms of the IA hypothesis of autonomic activity. The stronger BVP and RESPR responses and the weaker PTEMP reactions of the high-risk IA abusers indicate the sympathetic nervous system was heavily activated in these individuals. However, SC activates parasympathetic responses at the same time in the high-risk IA abusers. The paradoxical responses between the sympathetic and parasympathetic actions are addressed in the discussion.

  1. Autonomous target tracking of UAVs based on low-power neural network hardware

    Science.gov (United States)

    Yang, Wei; Jin, Zhanpeng; Thiem, Clare; Wysocki, Bryant; Shen, Dan; Chen, Genshe

    2014-05-01

    Detecting and identifying targets in unmanned aerial vehicle (UAV) images and videos have been challenging problems due to various types of image distortion. Moreover, the significantly high processing overhead of existing image/video processing techniques and the limited computing resources available on UAVs force most of the processing tasks to be performed by the ground control station (GCS) in an off-line manner. In order to achieve fast and autonomous target identification on UAVs, it is thus imperative to investigate novel processing paradigms that can fulfill the real-time processing requirements, while fitting the size, weight, and power (SWaP) constrained environment. In this paper, we present a new autonomous target identification approach on UAVs, leveraging the emerging neuromorphic hardware which is capable of massively parallel pattern recognition processing and demands only a limited level of power consumption. A proof-of-concept prototype was developed based on a micro-UAV platform (Parrot AR Drone) and the CogniMemTMneural network chip, for processing the video data acquired from a UAV camera on the y. The aim of this study was to demonstrate the feasibility and potential of incorporating emerging neuromorphic hardware into next-generation UAVs and their superior performance and power advantages towards the real-time, autonomous target tracking.

  2. Fibonacci-based hardware post-processing for non-autonomous signum hyperchaotic system

    KAUST Repository

    Mansingka, Abhinav S.

    2013-12-01

    This paper presents a hardware implementation of a robust non-autonomous hyperchaotic-based PRNG driven by a 256-bit LFSR. The original chaotic output is post-processed using a novel technique based on the Fibonacci series, bitwise XOR, rotation, and feedback. The proposed post-processing technique preserves the throughput of the system and enhances the randomness in the output which is verified by successfully passing all NIST SP. 800-22 tests. The system is realized on a Xilinx Virtex 4 FPGA achieving throughput up to 13.165 Gbits/s for 16-bit bus-width surpassing previously reported CB-PRNGs. © 2013 IEEE.

  3. A Behavior-based Approach for Multi-agent Q-learning for Autonomous Exploration

    CERN Document Server

    Ray, Dip Narayan; Mukhopadhyay, Sumit

    2011-01-01

    The use of mobile robots is being popular over the world mainly for autonomous explorations in hazardous/ toxic or unknown environments. This exploration will be more effective and efficient if the explorations in unknown environment can be aided with the learning from past experiences. Currently reinforcement learning is getting more acceptances for implementing learning in robots from the system-environment interactions. This learning can be implemented using the concept of both single-agent and multiagent. This paper describes such a multiagent approach for implementing a type of reinforcement learning using a priority based behaviour-based architecture. This proposed methodology has been successfully tested in both indoor and outdoor environments.

  4. Design of a vision-based sensor for autonomous pighouse cleaning

    DEFF Research Database (Denmark)

    Braithwaite, Ian David; Blanke, Mogens; Zhang, Guo-Quiang

    2005-01-01

    of designing a vision-based system to locate dirty areas and subsequently direct a cleaning robot to remove dirt. Novel results include the characterisation of the spectral properties of real surfaces and dirt in a pig house and the design of illumination to obtain discrimination of clean from dirty areas...... with a low probability of misclassification. A Bayesian discriminator is shown to be efficient in this context and implementation of a prototype tool demonstrates the feasibility of designing a low-cost vision-based sensor for autonomous cleaning....

  5. Design of a vision-based sensor for autonomous pighouse cleaning

    DEFF Research Database (Denmark)

    Braithwaite, Ian David; Blanke, Mogens; Zhang, Guo-Quiang;

    2005-01-01

    of designing a vision-based system to locate dirty areas and subsequently direct a cleaning robot to remove dirt. Novel results include the characterisation of the spectral properties of real surfaces and dirt in a pig house and the design of illumination to obtain discrimination of clean from dirty areas...... with a low probability of misclassification. A Bayesian discriminator is shown to be efficient in this context and implementation of a prototype tool demonstrates the feasibility of designing a low-cost vision-based sensor for autonomous cleaning....

  6. Autonomous Control of Eye Based Electric Wheel Chair with Obstacle Avoidance and Shortest Path Findings Based on Dijkstra Algorithm

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2011-12-01

    Full Text Available Autonomous Eye Based Electric Wheel Chair: EBEWC control system which allows handicap person (user to control their EWC with their eyes only is proposed. Using EBEWC, user can move to anywhere they want on a same floor in a hospital autonomously with obstacle avoidance with visible camera and ultrasonic sensor. User also can control EBEWC by their eyes. The most appropriate route has to be determined with avoiding obstacles and then autonomous real time control has to be done. Such these processing time and autonomous obstacle avoidance together with the most appropriate route determination are important for the proposed EBEWC. All the required performances are evaluated and validated. Obstacles can be avoided using acquired images with forward looking camera. The proposed EBEWC system allows creation of floor layout map that contains obstacles locations in a real time basis. The created and updated maps can be share by the electric wheel chairs on a same floor of a hospital. Experimental data show that the system allows computer input (more than 80 keys almost perfectly and electric wheel chair can be controlled with human eyes-only safely.

  7. Advancing Autonomous Operations for Deep Space Vehicles

    Science.gov (United States)

    Haddock, Angie T.; Stetson, Howard K.

    2014-01-01

    Starting in Jan 2012, the Advanced Exploration Systems (AES) Autonomous Mission Operations (AMO) Project began to investigate the ability to create and execute "single button" crew initiated autonomous activities [1]. NASA Marshall Space Flight Center (MSFC) designed and built a fluid transfer hardware test-bed to use as a sub-system target for the investigations of intelligent procedures that would command and control a fluid transfer test-bed, would perform self-monitoring during fluid transfers, detect anomalies and faults, isolate the fault and recover the procedures function that was being executed, all without operator intervention. In addition to the development of intelligent procedures, the team is also exploring various methods for autonomous activity execution where a planned timeline of activities are executed autonomously and also the initial analysis of crew procedure development. This paper will detail the development of intelligent procedures for the NASA MSFC Autonomous Fluid Transfer System (AFTS) as well as the autonomous plan execution capabilities being investigated. Manned deep space missions, with extreme communication delays with Earth based assets, presents significant challenges for what the on-board procedure content will encompass as well as the planned execution of the procedures.

  8. Hierarchical flight control system synthesis for rotorcraft-based unmanned aerial vehicles

    Science.gov (United States)

    Shim, Hyunchul

    The Berkeley Unmanned Aerial Vehicle (UAV) research aims to design, implement, and analyze a group of autonomous intelligent UAVs and UGVs (Unmanned Ground Vehicles). The goal of this dissertation is to provide a comprehensive procedural methodology to design, implement, and test rotorcraft-based unmanned aerial vehicles (RUAVs). We choose the rotorcraft as the base platform for our aerial agents because it offers ideal maneuverability for our target scenarios such as the pursuit-evasion game. Aided by many enabling technologies such as lightweight and powerful computers, high-accuracy navigation sensors and communication devices, it is now possible to construct RUAVs capable of precise navigation and intelligent behavior by the decentralized onboard control system. Building a fully functioning RUAV requires a deep understanding of aeronautics, control theory and computer science as well as a tremendous effort for implementation. These two aspects are often inseparable and therefore equally highlighted throughout this research. The problem of multiple vehicle coordination is approached through the notion of a hierarchical system. The idea behind the proposed architecture is to build a hierarchical multiple-layer system that gradually decomposes the abstract mission objectives into the physical quantities of control input. Each RUAV incorporated into this system performs the given tasks and reports the results through the hierarchical communication channel back to the higher-level coordinator. In our research, we provide a theoretical and practical approach to build a number of RUAVs based on commercially available navigation sensors, computer systems, and radio-controlled helicopters. For the controller design, the dynamic model of the helicopter is first built. The helicopter exhibits a very complicated multi-input multi-output, nonlinear, time-varying and coupled dynamics, which is exposed to severe exogenous disturbances. This poses considerable difficulties for

  9. Autonomous Navigation Based on SEIF with Consistency Constraint for C-Ranger AUV

    Directory of Open Access Journals (Sweden)

    Yue Shen

    2015-01-01

    Full Text Available An autonomous underwater vehicle (AUV has to solve two essential problems in underwater environment, namely, localization and mapping. SLAM is one novel solution to estimate locations and maps simultaneously based on motion models and sensor measurements. Sparse extended information filter (SEIF is an effective algorithm to reduce storage and computational costs of large-scale maps in the SLAM problem. However, there exists the inconsistency in the SEIF since the rank of the observability matrix of linearized error-state model in SLAM system is higher than that of the nonlinear SLAM system. By analyzing the consistency of the SEIF-based SLAM from the perspective of observability, a SLAM based on SEIF with consistency constraint (SEIF-CC SLAM is developed to improve the estimator’s consistency. The proposed algorithm uses the first-ever available estimates to calculate SEIF Jacobians for each of the state variables, called the First Estimates Jacobian (FEJ. Then, the linearized error-state model can keep the same observability as the underlying nonlinear SLAM system. The capability of autonomous navigation with the proposed algorithm is validated through simulations experiments and sea trials for a C-Ranger AUV. Experimental results show that the proposed SEIF-CC SLAM algorithm yields more consistent and accurate estimates compared with the SEIF-based SLAM.

  10. Safety Verification of a Fault Tolerant Reconfigurable Autonomous Goal-Based Robotic Control System

    Science.gov (United States)

    Braman, Julia M. B.; Murray, Richard M; Wagner, David A.

    2007-01-01

    Fault tolerance and safety verification of control systems are essential for the success of autonomous robotic systems. A control architecture called Mission Data System (MDS), developed at the Jet Propulsion Laboratory, takes a goal-based control approach. In this paper, a method for converting goal network control programs into linear hybrid systems is developed. The linear hybrid system can then be verified for safety in the presence of failures using existing symbolic model checkers. An example task is simulated in MDS and successfully verified using HyTech, a symbolic model checking software for linear hybrid systems.

  11. Autonomous navigation vehicle system based on robot vision and multi-sensor fusion

    Science.gov (United States)

    Wu, Lihong; Chen, Yingsong; Cui, Zhouping

    2011-12-01

    The architecture of autonomous navigation vehicle based on robot vision and multi-sensor fusion technology is expatiated in this paper. In order to acquire more intelligence and robustness, accurate real-time collection and processing of information are realized by using this technology. The method to achieve robot vision and multi-sensor fusion is discussed in detail. The results simulated in several operating modes show that this intelligent vehicle has better effects in barrier identification and avoidance and path planning. And this can provide higher reliability during vehicle running.

  12. Temporal Memory Reinforcement Learning for the Autonomous Micro-mobile Robot Based-behavior

    Institute of Scientific and Technical Information of China (English)

    Yang Yujun(杨玉君); Cheng Junshi; Chen Jiapin; Li Xiaohai

    2004-01-01

    This paper presents temporal memory reinforcement learning for the autonomous micro-mobile robot based-behavior. Human being has a memory oblivion process, i.e. the earlier to memorize, the earlier to forget, only the repeated thing can be remembered firmly. Enlightening forms this, and the robot need not memorize all the past states, at the same time economizes the EMS memory space, which is not enough in the MPU of our AMRobot. The proposed algorithm is an extension of the Q-learning, which is an incremental reinforcement learning method. The results of simulation have shown that the algorithm is valid.

  13. A guidance law for UAV autonomous aerial refueling based on the iterative computation method

    Directory of Open Access Journals (Sweden)

    Luo Delin

    2014-08-01

    Full Text Available The rendezvous and formation problem is a significant part for the unmanned aerial vehicle (UAV autonomous aerial refueling (AAR technique. It can be divided into two major phases: the long-range guidance phase and the formation phase. In this paper, an iterative computation guidance law (ICGL is proposed to compute a series of state variables to get the solution of a control variable for a UAV conducting rendezvous with a tanker in AAR. The proposed method can make the control variable converge to zero when the tanker and the UAV receiver come to a formation flight eventually. For the long-range guidance phase, the ICGL divides it into two sub-phases: the correction sub-phase and the guidance sub-phase. The two sub-phases share the same iterative process. As for the formation phase, a velocity coordinate system is created by which control accelerations are designed to make the speed of the UAV consistent with that of the tanker. The simulation results demonstrate that the proposed ICGL is effective and robust against wind disturbance.

  14. A guidance law for UAV autonomous aerial refueling based on the iterative computation method

    Institute of Scientific and Technical Information of China (English)

    Luo Delin; Xie Rongzeng; Duan Haibin

    2014-01-01

    The rendezvous and formation problem is a significant part for the unmanned aerial vehicle (UAV) autonomous aerial refueling (AAR) technique. It can be divided into two major phases: the long-range guidance phase and the formation phase. In this paper, an iterative computation guidance law (ICGL) is proposed to compute a series of state variables to get the solu-tion of a control variable for a UAV conducting rendezvous with a tanker in AAR. The proposed method can make the control variable converge to zero when the tanker and the UAV receiver come to a formation flight eventually. For the long-range guidance phase, the ICGL divides it into two sub-phases: the correction sub-phase and the guidance sub-phase. The two sub-phases share the same iterative process. As for the formation phase, a velocity coordinate system is created by which control accelerations are designed to make the speed of the UAV consistent with that of the tanker. The simulation results demonstrate that the proposed ICGL is effective and robust against wind disturbance.

  15. Radar seeker based autonomous navigation update system using topography feature matching techniques

    Science.gov (United States)

    Lerche, H. D.; Tumbreagel, F.

    1992-11-01

    The discussed navigation update system was designed for an unmanned platform with fire and forget capability. It meets the requirement due to fully autonomous operation. The system concept will be characterized by complementary use of the radar seeker for target identification as well as for navigation function. The system works in the navigation mode during preprogrammable phases where the primary target identification function is not active or in parallel processing. The dual function radar seeker system navigates the drone during the midcourse and terminal phases of the mission. Its high resolution due to range measurement and doppler beam sharpening in context with its radar reflectivity sensing capability are the basis for topography referenced navigation computation. The detected height jumps (coming from terrain elevation and cultural objects) and radar reflectivity features will be matched together with topography referenced features. The database comprises elevation data and selected radar reflectivity features that are robust against seasonal influences. The operational benefits of the discussed system are as follows: (1) the improved navigation performance with high probability of position fixing, even over flat terrain; (2) the operation within higher altitudes; and (3) bad weather capability. The developed software modules were verified with captive flight test data running in a hardware-in-the-loop simulation.

  16. Hand-eye-vision based control for an inspection robot’s autonomous line grasping

    Institute of Scientific and Technical Information of China (English)

    王伟; 吴功平; 白玉成; 肖华; 杨智勇; 严宇; 何缘; 徐显金; 苏帆

    2014-01-01

    In order to ensure that the off-line arm of a two-arm-wheel combined inspection robot can reliably grasp the line in case of autonomous obstacle crossing, a control method is proposed for line grasping based on hand-eye visual servo. On the basis of the transmission line’s geometrical characteristics and the camera’s imaging principle, a line recognition and extraction method based on structure constraint is designed. The line’s intercept and inclination are defined in an imaging space to represent the robot’s change of pose and a law governing the pose decoupling servo control is developed. Under the integrated consideration of the influence of light intensity and background change, noise (from the camera itself and electromagnetic field) as well as the robot’s kinetic inertia on the robot’s imaging quality in the course of motion and the grasping control precision, a servo controller for grasping the line of the robot’s off-line arm is designed with the method of fuzzy control. An experiment is conducted on a 1:1 simulation line using an inspection robot and the robot is put into on-line operation on a real overhead transmission line, where the robot can grasp the line within 18 s in the case of autonomous obstacle-crossing. The robot’s autonomous line-grasping function is realized without manual intervention and the robot can grasp the line in a precise, reliable and efficient manner, thus the need of actual operation can be satisfied.

  17. Differences in Characteristics of Aviation Accidents during 1993-2012 Based on Flight Purpose

    Science.gov (United States)

    Evans, Joni K.

    2016-01-01

    Usually aviation accidents are categorized and analyzed within flight conduct rules (Part 121, Part 135, Part 91) because differences in accident rates within flight rules have been demonstrated. Even within a particular flight rule the flights have different purposes. For many, Part 121 flights are synonymous with scheduled passenger transport, and indeed this is the largest group of Part 121 accidents. But there are also non-scheduled (charter) passenger transport and cargo flights. The primary purpose of the analysis reported here is to examine the differences in aviation accidents based on the purpose of the flight. Some of the factors examined are the accident severity, aircraft characteristics and accident occurrence categories. Twenty consecutive years of data were available and utilized to complete this analysis.

  18. Vision-aided Navigation for Autonomous Aircraft Based on Unscented Kalman Filter

    Directory of Open Access Journals (Sweden)

    Junwei Yu

    2013-02-01

    Full Text Available A vision-aided navigation system for autonomous aircraft is described in this paper. The vision navigation of the aircraft to the known scence is performed with a camera fixed on the aircraft. The location and pose of the aircraft are estimated with the corresponding control points which can be detected in the images captured. The control points are selected according their saliency and are tracked in sequential images based on Fourier-Melline transform. The simulation model of the aircraft dynamics and vision-aided navigation system based on Matlab/Simulink is built.The unscented Kalman filter is used to fuse the aircraft state information provided by the vision system and the inertial navigation system. Simulation results show that the vision-based navigation system provides satisfactory results of both accuracy and reliability.

  19. Vision-based Estimation of Relative Pose in Autonomous Aerial Refueling

    Institute of Scientific and Technical Information of China (English)

    DING Meng; WEI Li; WANG Bangfeng

    2011-01-01

    The lack of autonomous aerial refueling capabilities is one of the greatest limitations of unmanned aerial vehicles.This paper discusses the vision-based estimation of the relative pose of a tanker and unmanned aerial vehicle,which is a key issue in autonomous aerial refueling.The main task of this paper is to study the relative pose estimation for a tanker and unmanned aerial vehicle in the phase of commencing refueling and during refueling.The employed algorithm includes the initialization of the orientation parameters and an orthogonal iteration algorithm to estimate the optimal solution of rotation matrix and translation vector.In simulation experiments,because of the small variation in the rotation angle in aerial refueling,the method in which the initial rotation matrix is the identity matrix is found to be the most stable and accurate among methods.Finally,the paper discusses the effects of the number and configuration of feature points on the accuracy of the estimation results when using this method.

  20. Perancangan Autonomous Landing pada Quadcopter Menggunakan Behavior-Based Intelligent Fuzzy Control

    Directory of Open Access Journals (Sweden)

    Chalidia Nurin Hamdani

    2013-09-01

    Full Text Available Quadcopter adalah salah satu platform unmanned aerial vehicle (UAV yang saat ini banyak diriset karena kemampuannya melakukan take-off dan landing secara vertikal. Karena menggunakan 4 motor brushless sebagai penggerak utama, quadcopter memiliki kompleksitas yang cukup tinggi baik dalam pemodelan maupun pengendalian. Landing merupakan salah satu mekanisme pada quadcopter yang membutuhkan kecepatan yang akurat dan aman dengan tetap mempertahankan keseimbangan. Pada penelitian ini, penulis menggunakan Behavior-Based Intelligent Fuzzy Control (BBIFC sebagai dasar kontrol untuk penerapan autonomous landing pada quadcopter. BBIFC adalah salah satu skema high-level control di mana desain kontrol terdiri dari beberapa layer. Ada 2 layer yang digunakan pada penelitian ini yaitu layer untuk pengendalian sudut pitch, roll, yaw dan layer untuk pengendalian ketinggian. Setiap layer memiliki mekanisme kontrol yang berbeda yang didesain menggunakan Intelligent Fuzzy Controller dan kontroler PID. Dengan metode ini dihasilkan algoritma untuk mekanisme safe autonomous landing dengan mengikuti sinyal eksponensial di mana quadcopter mencapai titik 0 (nol meter dalam waktu 15 detik dan Kontroler PID dapat mengendalikan keseimbangan quadcopter dalam waktu 7.97 detik untuk roll dan pitch serta 1.25 detik untuk yaw sejak gangguan sudut diberikan.

  1. An Optimized, Data Distribution Service-Based Solution for Reliable Data Exchange Among Autonomous Underwater Vehicles.

    Science.gov (United States)

    Rodríguez-Molina, Jesús; Bilbao, Sonia; Martínez, Belén; Frasheri, Mirgita; Cürüklü, Baran

    2017-08-05

    Major challenges are presented when managing a large number of heterogeneous vehicles that have to communicate underwater in order to complete a global mission in a cooperative manner. In this kind of application domain, sending data through the environment presents issues that surpass the ones found in other overwater, distributed, cyber-physical systems (i.e., low bandwidth, unreliable transport medium, data representation and hardware high heterogeneity). This manuscript presents a Publish/Subscribe-based semantic middleware solution for unreliable scenarios and vehicle interoperability across cooperative and heterogeneous autonomous vehicles. The middleware relies on different iterations of the Data Distribution Service (DDS) software standard and their combined work between autonomous maritime vehicles and a control entity. It also uses several components with different functionalities deemed as mandatory for a semantic middleware architecture oriented to maritime operations (device and service registration, context awareness, access to the application layer) where other technologies are also interweaved with middleware (wireless communications, acoustic networks). Implementation details and test results, both in a laboratory and a deployment scenario, have been provided as a way to assess the quality of the system and its satisfactory performance.

  2. An Optimized, Data Distribution Service-Based Solution for Reliable Data Exchange Among Autonomous Underwater Vehicles

    Directory of Open Access Journals (Sweden)

    Jesús Rodríguez-Molina

    2017-08-01

    Full Text Available Major challenges are presented when managing a large number of heterogeneous vehicles that have to communicate underwater in order to complete a global mission in a cooperative manner. In this kind of application domain, sending data through the environment presents issues that surpass the ones found in other overwater, distributed, cyber-physical systems (i.e., low bandwidth, unreliable transport medium, data representation and hardware high heterogeneity. This manuscript presents a Publish/Subscribe-based semantic middleware solution for unreliable scenarios and vehicle interoperability across cooperative and heterogeneous autonomous vehicles. The middleware relies on different iterations of the Data Distribution Service (DDS software standard and their combined work between autonomous maritime vehicles and a control entity. It also uses several components with different functionalities deemed as mandatory for a semantic middleware architecture oriented to maritime operations (device and service registration, context awareness, access to the application layer where other technologies are also interweaved with middleware (wireless communications, acoustic networks. Implementation details and test results, both in a laboratory and a deployment scenario, have been provided as a way to assess the quality of the system and its satisfactory performance.

  3. Autonomous shooting at middle size space debris objects from space-based APT laser systems

    Science.gov (United States)

    Gambi, J. M.; García del Pino, M. L.

    2017-02-01

    This paper is motivated by the need of removing middle size space debris objects. It deals with the problem of increasing the pointing accuracy while shooting at these objects by means of autonomous space-based APT systems endowed with very narrow laser beams. It is shown that shooting at these objects with these systems is the one single ballistic problem that becomes singular in space. This means that the shooting direction that is to be implemented by any of these systems to reach an object at a given instant can only be hopefully implemented after the object has been previously reached. Thus, the problem becomes backwards recurrent with no end for any object-system configuration, except when the LOS direction remains constant for some period of time. It is also shown that the implementation of the point-ahead angles from the data acquired prior to the respective shootings is essential to keep accuracy. In fact, one single omission during the action may cause errors larger than the size of the objects. As a consequence, we find that there is only one way for an autonomous system to minimize the pointing errors: any shooting sequence to any of these objects must be started when the transverse component of the relative velocity of the object with respect to the system is zero (actually, as close to zero as possible).

  4. A Sampling Based Approach to Spacecraft Autonomous Maneuvering with Safety Specifications

    Science.gov (United States)

    Starek, Joseph A.; Barbee, Brent W.; Pavone, Marco

    2015-01-01

    This paper presents a methods for safe spacecraft autonomous maneuvering that leverages robotic motion-planning techniques to spacecraft control. Specifically the scenario we consider is an in-plan rendezvous of a chaser spacecraft in proximity to a target spacecraft at the origin of the Clohessy Wiltshire Hill frame. The trajectory for the chaser spacecraft is generated in a receding horizon fashion by executing a sampling based robotic motion planning algorithm name Fast Marching Trees (FMT) which efficiently grows a tree of trajectories over a set of probabillistically drawn samples in the state space. To enforce safety the tree is only grown over actively safe samples for which there exists a one-burn collision avoidance maneuver that circularizes the spacecraft orbit along a collision-free coasting arc and that can be executed under potential thrusters failures. The overall approach establishes a provably correct framework for the systematic encoding of safety specifications into the spacecraft trajectory generations process and appears amenable to real time implementation on orbit. Simulation results are presented for a two-fault tolerant spacecraft during autonomous approach to a single client in Low Earth Orbit.

  5. Autonomous Driver Based on an Intelligent System of Decision-Making.

    Science.gov (United States)

    Czubenko, Michał; Kowalczuk, Zdzisław; Ordys, Andrew

    The paper presents and discusses a system (xDriver) which uses an Intelligent System of Decision-making (ISD) for the task of car driving. The principal subject is the implementation, simulation and testing of the ISD system described earlier in our publications (Kowalczuk and Czubenko in artificial intelligence and soft computing lecture notes in computer science, lecture notes in artificial intelligence, Springer, Berlin, 2010, 2010, In Int J Appl Math Comput Sci 21(4):621-635, 2011, In Pomiary Autom Robot 2(17):60-5, 2013) for the task of autonomous driving. The design of the whole ISD system is a result of a thorough modelling of human psychology based on an extensive literature study. Concepts somehow similar to the ISD system can be found in the literature (Muhlestein in Cognit Comput 5(1):99-105, 2012; Wiggins in Cognit Comput 4(3):306-319, 2012), but there are no reports of a system which would model the human psychology for the purpose of autonomously driving a car. The paper describes assumptions for simulation, the set of needs and reactions (characterizing the ISD system), the road model and the vehicle model, as well as presents some results of simulation. It proves that the xDriver system may behave on the road as a very inexperienced driver.

  6. A simulator-based study of in-flight auscultation.

    Science.gov (United States)

    Tourtier, Jean-Pierre; Libert, Nicolas; Clapson, Patrick; Dubourdieu, Stéphane; Jost, Daniel; Tazarourte, Karim; Astaud, Cécil-Emmanuel; Debien, Bruno; Auroy, Yves

    2014-04-01

    The use of a stethoscope is essential to the delivery of continuous, supportive en route care during aeromedical evacuations. We compared the capability of 2 stethoscopes (electronic, Litmann 3000; conventional, Litmann Cardiology III) at detecting pathologic heart and lung sounds, aboard a C135, a medical transport aircraft. Sounds were mimicked using a mannequin-based simulator SimMan. Five practitioners examined the mannequin during a fly, with a variety of abnormalities as follows: crackles, wheezing, right and left lung silence, as well as systolic, diastolic, and Austin-Flint murmur. The comparison for diagnosis assessed (correct or wrong) between using the electronic and conventional stethoscopes were performed as a McNemar test. A total of 70 evaluations were performed. For cardiac sounds, diagnosis was right in 0/15 and 4/15 auscultations, respectively, with conventional and electronic stethoscopes (McNemar test, P = 0.13). For lung sounds, right diagnosis was found with conventional stethoscope in 10/20 auscultations versus 18/20 with electronic stethoscope (P = 0.013). Flight practitioners involved in aeromedical evacuation on C135 plane are more able to practice lung auscultation on a mannequin with this amplified stethoscope than with the traditional one. No benefit was found for heart sounds.

  7. Information distribution in distributed microprocessor based flight control systems

    Science.gov (United States)

    Montgomery, R. C.; Lee, P. S.

    1977-01-01

    This paper presents an optimal control theory that accounts for variable time intervals in the information distribution to control effectors in a distributed microprocessor based flight control system. The theory is developed using a linear process model for the aircraft dynamics and the information distribution process is modeled as a variable time increment process where, at the time that information is supplied to the control effectors, the control effectors know the time of the next information update only in a stochastic sense. An optimal control problem is formulated and solved that provides the control law that minimizes the expected value of a quadratic cost function. An example is presented where the theory is applied to the control of the longitudinal motions of the F8-DFBW aircraft. Theoretical and simulation results indicate that, for the example problem, the optimal cost obtained using a variable time increment Markov information update process where the control effectors know only the past information update intervals and the Markov transition mechanism is almost identical to that obtained using a known uniform information update interval.

  8. Automated Flight Safety Inference Engine (AFSIE) System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop an innovative Autonomous Flight Safety Inference Engine (AFSIE) system to autonomously and reliably terminate the flight of an errant launch...

  9. Multicast Address Management and Connection Control Based on Hierarchical Autonomous Structure

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; ZHANG Fuyan

    1999-01-01

    Multicast capability, including multicast address and multicast routing mechanisms, at the network layeris necessary in order to reduce the bandwidth requirements of multiparty, multicast applications. Based on hierarchical autonomous structure in accordance with the self-organization topologies of Internet, the paper puts forward a multicast address management scheme that is shown to be robust and scalable. Connection control hierarchy (CCH) based on master/slave relationship and a simple efficient building algorithm of multi-point connection is also built. The paper also describes the normal operations of multicast address management andmulti-point connection controller. Through simulation experiment, HAM, CM and DDM of Multicast Address Allocation are compared. HAM integrates the merits of CM and DDM, which is efficient as a whole, robust andscalable. CCH raises the efficiency of connection control, and is highly robust, flexible and scalable.

  10. Robust Control Based on Feedback Linearization for Roll Stabilizing of Autonomous Underwater Vehicle Under Wave Disturbances

    Institute of Scientific and Technical Information of China (English)

    PAN Li-xin; JIN Hong-zhang; WANG Lin-lin

    2011-01-01

    In the case of Autonomous Underwater Vehicle (AUV) navigating with low speed near water surface, a new method for design of roll motion controller is proposed in order to restrain wave disturbance effectively and improve roll stabilizing performance. Robust control is applied, which is based on uncertain nonlinear horizontal motion model of AUV and the principle of zero speed fin stabilizer. Feedback linearization approach is used to transform the complex nonlinear system into a comparatively simple linear system. For parameter uncertainty of motion model, the controller is designed with mixed-sensitivity method based on H-infinity robust control theory. Simulation results show better robustness improved by this control method for roll stabilizing of AUV navigating near water surface.

  11. Incremental inverse kinematics based vision servo for autonomous robotic capture of non-cooperative space debris

    Science.gov (United States)

    Dong, Gangqi; Zhu, Z. H.

    2016-04-01

    This paper proposed a new incremental inverse kinematics based vision servo approach for robotic manipulators to capture a non-cooperative target autonomously. The target's pose and motion are estimated by a vision system using integrated photogrammetry and EKF algorithm. Based on the estimated pose and motion of the target, the instantaneous desired position of the end-effector is predicted by inverse kinematics and the robotic manipulator is moved incrementally from its current configuration subject to the joint speed limits. This approach effectively eliminates the multiple solutions in the inverse kinematics and increases the robustness of the control algorithm. The proposed approach is validated by a hardware-in-the-loop simulation, where the pose and motion of the non-cooperative target is estimated by a real vision system. The simulation results demonstrate the effectiveness and robustness of the proposed estimation approach for the target and the incremental control strategy for the robotic manipulator.

  12. Detection and Tracking Strategies for Autonomous Aerial Refuelling Tasks Based on Monocular Vision

    Directory of Open Access Journals (Sweden)

    Yingjie Yin

    2014-07-01

    Full Text Available Detection and tracking strategies based on monocular vision are proposed for autonomous aerial refuelling tasks. The drogue attached to the fuel tanker aircraft has two important features. The grey values of the drogue's inner part are different from the external umbrella ribs, as shown in the image. The shape of the drogue's inner dark part is nearly circular. According to crucial prior knowledge, the rough and fine positioning algorithms are designed to detect the drogue. Particle filter based on the drogue's shape is proposed to track the drogue. A strategy to switch between detection and tracking is proposed to improve the robustness of the algorithms. The inner dark part of the drogue is segmented precisely in the detecting and tracking process and the segmented circular part can be used to measure its spatial position. The experimental results show that the proposed method has good performance in real-time and satisfied robustness and positioning accuracy.

  13. Drogue detection for autonomous aerial refueling based on convolutional neural networks

    Directory of Open Access Journals (Sweden)

    Xufeng Wang

    2017-02-01

    Full Text Available Drogue detection is a fundamental issue during the close docking phase of autonomous aerial refueling (AAR. To cope with this issue, a novel and effective method based on deep learning with convolutional neural networks (CNNs is proposed. In order to ensure its robustness and wide application, a deep learning dataset of images was prepared by utilizing real data of “Probe and Drogue” aerial refueling, which contains diverse drogues in various environmental conditions without artificial features placed on the drogues. By employing deep learning ideas and graphics processing units (GPUs, a model for drogue detection using a Caffe deep learning framework with CNNs was designed to ensure the method’s accuracy and real-time performance. Experiments were conducted to demonstrate the effectiveness of the proposed method, and results based on real AAR data compare its performance to other methods, validating the accuracy, speed, and robustness of its drogue detection ability.

  14. Autonomous Navigation for Unmanned Aerial Vehicles Based on Chaotic Bionics Theory

    Institute of Scientific and Technical Information of China (English)

    Xiao-lei Yu; Yong-rong Sun; Jian-ye Liu; Bing-wen Chen

    2009-01-01

    In this paper a new reactive mechanism based on perception-action bionics for multi-sensory integration applied to Un-manned Aerial Vehicles (UAVs) navigation is proposed. The strategy is inspired by the olfactory bulb neural activity observed in rabbits subject to external stimuli. The new UAV navigation technique exploits the use of a muitiscroil chaotic system which i sable to be controlled in real-time towards less complex orbits, like periodic orbits or equilibrium points, considered as perceptive orbits. These are subject to real-time modifications on the basis of environment changes acquired through a Synthetic Aperture Radar (SAR) sensory system. The mathematical details of the approach are given including simulation results in a virtual en-vironment. The results demonstrate the capability of autonomous navigation for UAV based on chaotic bionics theory in com-plex spatial environments.

  15. An Improved Chaotic Motion Path Planner for Autonomous Mobile Robots based on a Logistic Map

    Directory of Open Access Journals (Sweden)

    Caihong Li

    2013-06-01

    Full Text Available This paper presents a chaotic motion path planner based on a Logistic Map (SCLCP for an autonomous mobile robot to cover an unknown terrain randomly, namely entirely, unpredictably and evenly. The path planner has been improved by arcsine and arccosine transformation. A motion path planner based only on the Logistic Chaotic Map (LCP can show chaotic behaviour, which possesses the chaotic characteristics of topological transitivity and unpredictability, but lacks better evenness. Therefore, the arcsine and arccosine transformations are used to enhance the randomness of LCP. The randomness of the followed path planner, LCP, the improved path planner SCLCP and the commonly used Random Path Planner (RP are discussed and compared under different sets of initial conditions and different iteration rounds. Simulation results confirm that a better evenness index of SCLCP can be obtained with regard to previous works.

  16. [Autonomic neuropathies].

    Science.gov (United States)

    Siepmann, T; Penzlin, A I; Illigens, B M W

    2013-07-01

    Autonomic neuropathies are a heterogeneous group of diseases that involve damage of small peripheral autonomic Aδ- and C-fibers. Causes of autonomic nerve fiber damage are disorders such as diabetes mellitus and HIV-infection. Predominant symptoms of autonomic neuropathy are orthostatic hypotension, gastro-intestinal problems, urogenital dysfunction, and cardiac arrhythmia, which can severely impair the quality of life in affected patients. Furthermore, autonomic neuropathies can be induced by autoimmune diseases such as acute inflammatory demyelinating polyneuropathy, hereditary disorders such as the lysosomal storage disorder Fabry disease and hereditary sensory and autonomic neuropathies, as well as certain toxins and drugs.

  17. The B-747 flight control system maintenance and reliability data base for cost effectiveness tradeoff studies

    Science.gov (United States)

    1982-01-01

    Primary and automatic flight controls are combined for a total flight control reliability and maintenance cost data base using information from two previous reports and additional cost data gathered from a major airline. A comparison of the current B-747 flight control system effects on reliability and operating cost with that of a B-747 designed for an active control wing load alleviation system is provided.

  18. A field robot for autonomous laser-based N2O flux measurements

    Science.gov (United States)

    Molstad, Lars; Reent Köster, Jan; Bakken, Lars; Dörsch, Peter; Lien, Torgrim; Overskeid, Øyvind; Utstumo, Trygve; Løvås, Daniel; Brevik, Anders

    2014-05-01

    N2O measurements in multi-plot field trials are usually carried out by chamber-based manual gas sampling and subsequent laboratory-based gas chromatographic N2O determination. Spatial and temporal resolution of these measurements are commonly limited by available manpower. However, high spatial and temporal variability of N2O fluxes within individual field plots can add large uncertainties to time- and area-integrated flux estimates. Detailed mapping of this variability would improve these estimates, as well as help our understanding of the factors causing N2O emissions. An autonomous field robot was developed to increase the sampling frequency and to operate outside normal working hours. The base of this system was designed as an open platform able to carry versatile instrumentation. It consists of an electrically motorized platform powered by a lithium-ion battery pack, which is capable of autonomous navigation by means of a combined high precision real-time kinematic (RTK) GPS and an inertial measurement unit (IMU) system. On this platform an elevator is mounted, carrying a lateral boom with a static chamber on each side of the robot. Each chamber is equipped with a frame of plastic foam to seal the chamber when lowered onto the ground by the elevator. N2O flux from the soil covered by the two chambers is sequentially determined by circulating air between each chamber and a laser spectrometer (DLT-100, Los Gatos Research, Mountain View, CA, USA), which monitors the increase in N2O concentration. The target enclosure time is 1 - 2 minutes, but may be longer when emissions are low. CO2 concentrations are determined by a CO2/H2O gas analyzer (LI-840A, LI-COR Inc., Lincoln, NE, USA). Air temperature and air pressure inside both chambers are continuously monitored and logged. Wind speed and direction are monitored by a 3D sonic anemometer on top of the elevator boom. This autonomous field robot can operate during day and night time, and its working hours are only

  19. Intelligent Agent based Flight Search and Booking System

    Directory of Open Access Journals (Sweden)

    Floyd Garvey

    2012-07-01

    Full Text Available The world globalization is widely used, and there are several definitions that may fit this one word. However the reality remains that globalization has impacted and is impacting each individual on this planet. It is defined to be greater movement of people, goods, capital and ideas due to increased economic integration, which in turn is propelled, by increased trade and investment. It is like moving towards living in a borderless world. With the reality of globalization, the travel industry has benefited significantly. It could be said that globalization is benefiting from the flight industry. Regardless of the way one looks at it, more persons are traveling each day and are exploring several places that were distant places on a map. Equally, technology has been growing at an increasingly rapid pace and is being utilized by several persons all over the world. With the combination of globalization and the increase in technology and the frequency in travel there is a need to provide an intelligent application that is capable to meeting the needs of travelers that utilize mobile phones all over. It is a solution that fits in perfectly to a user’s busy lifestyle, offers ease of use and enough intelligence that makes a user’s experience worthwhile. Having recognized this need, the Agent based Mobile Airline Search and Booking System is been developed that is built to work on the Android to perform Airline Search and booking using Biometric. The system also possess agent learning capability to perform the search of Airlines based on some previous search pattern .The development been carried out using JADE-LEAP Agent development kit on Android.

  20. An enhanced dynamic Delaunay triangulation-based path planning algorithm for autonomous mobile robot navigation

    Science.gov (United States)

    Chen, Jun; Luo, Chaomin; Krishnan, Mohan; Paulik, Mark; Tang, Yipeng

    2010-01-01

    An enhanced dynamic Delaunay Triangulation-based (DT) path planning approach is proposed for mobile robots to plan and navigate a path successfully in the context of the Autonomous Challenge of the Intelligent Ground Vehicle Competition (www.igvc.org). The Autonomous Challenge course requires the application of vision techniques since it involves path-based navigation in the presence of a tightly clustered obstacle field. Course artifacts such as switchbacks, ramps, dashed lane lines, trap etc. are present which could turn the robot around or cause it to exit the lane. The main contribution of this work is a navigation scheme based on dynamic Delaunay Triangulation (DDT) that is heuristically enhanced on the basis of a sense of general lane direction. The latter is computed through a "GPS (Global Positioning System) tail" vector obtained from the immediate path history of the robot. Using processed data from a LADAR, camera, compass and GPS unit, a composite local map containing both obstacles and lane line segments is built up and Delaunay Triangulation is continuously run to plan a path. This path is heuristically corrected, when necessary, by taking into account the "GPS tail" . With the enhancement of the Delaunay Triangulation by using the "GPS tail", goal selection is successfully achieved in a majority of situations. The robot appears to follow a very stable path while navigating through switchbacks and dashed lane line situations. The proposed enhanced path planning and GPS tail technique has been successfully demonstrated in a Player/Stage simulation environment. In addition, tests on an actual course are very promising and reveal the potential for stable forward navigation.

  1. Simulation to Flight Test for a UAV Controls Testbed

    Science.gov (United States)

    Motter, Mark A.; Logan, Michael J.; French, Michael L.; Guerreiro, Nelson M.

    2006-01-01

    The NASA Flying Controls Testbed (FLiC) is a relatively small and inexpensive unmanned aerial vehicle developed specifically to test highly experimental flight control approaches. The most recent version of the FLiC is configured with 16 independent aileron segments, supports the implementation of C-coded experimental controllers, and is capable of fully autonomous flight from takeoff roll to landing, including flight test maneuvers. The test vehicle is basically a modified Army target drone, AN/FQM-117B, developed as part of a collaboration between the Aviation Applied Technology Directorate (AATD) at Fort Eustis, Virginia and NASA Langley Research Center. Several vehicles have been constructed and collectively have flown over 600 successful test flights, including a fully autonomous demonstration at the Association of Unmanned Vehicle Systems International (AUVSI) UAV Demo 2005. Simulations based on wind tunnel data are being used to further develop advanced controllers for implementation and flight test.

  2. Vision-based flight control in the hawkmoth Hyles lineata.

    Science.gov (United States)

    Windsor, Shane P; Bomphrey, Richard J; Taylor, Graham K

    2014-02-06

    Vision is a key sensory modality for flying insects, playing an important role in guidance, navigation and control. Here, we use a virtual-reality flight simulator to measure the optomotor responses of the hawkmoth Hyles lineata, and use a published linear-time invariant model of the flight dynamics to interpret the function of the measured responses in flight stabilization and control. We recorded the forces and moments produced during oscillation of the visual field in roll, pitch and yaw, varying the temporal frequency, amplitude or spatial frequency of the stimulus. The moths' responses were strongly dependent upon contrast frequency, as expected if the optomotor system uses correlation-type motion detectors to sense self-motion. The flight dynamics model predicts that roll angle feedback is needed to stabilize the lateral dynamics, and that a combination of pitch angle and pitch rate feedback is most effective in stabilizing the longitudinal dynamics. The moths' responses to roll and pitch stimuli coincided qualitatively with these functional predictions. The moths produced coupled roll and yaw moments in response to yaw stimuli, which could help to reduce the energetic cost of correcting heading. Our results emphasize the close relationship between physics and physiology in the stabilization of insect flight.

  3. Understanding macrophage differentiation during space flight: The importance of ground-based experiments before space flight.

    Science.gov (United States)

    Chapes, Stephen K; Ortega, M Teresa

    2013-06-01

    In preparation for a space flight on STS-126, two in vitro culture systems were used to investigate macrophage colony stimulating factor-dependent macrophage differentiation from mouse primary bone marrow cells. The patented Techshot Cell Cult Bioreactor and the BioServe Fluid Processing Apparatus (FPA) were operated in different orientations to determine their impact on macrophage growth and differentiation. Bone marrow cell parameters were determined after cells were grown in FPAs incubated at 37°C in vertical or horizontal orientations, and macrophage cell recovery was significantly higher from FPAs that were incubated in the horizontal orientation compared to "vertical" FPAs. Similarly, when bone marrow cells were grown in the Techshot bioreactor, there were significant differences in the numbers of macrophages recovered after 7 days, depending on movement and orientation of the bioreactor. Macrophage recovery was highest when the patented bioreactor was rotated in the horizontal, x-axis plane (merry-go-round fashion) compared to static and vertically, y-axis plane rotated (Ferris wheel fashion) bioreactors. In addition, the expression of F4/80 and other differentiation markers varied depending on whether macrophages differentiated in FPAs or in bioreactors. After 7 days, significant differences in size, granularity and molecule expression were seen even when the same primary bone marrow cells were used to seed the cultures. These data show that culture outcomes are highly dependent on the culture device and device orientation. Moreover, the impact of the culture system needs to be understood in order to interpret space flight data.

  4. Autonomous docking based on infrared system for electric vehicle charging in urban areas.

    Science.gov (United States)

    Pérez, Joshué; Nashashibi, Fawzi; Lefaudeux, Benjamin; Resende, Paulo; Pollard, Evangeline

    2013-02-21

    Electric vehicles are progressively introduced in urban areas, because of their ability to reduce air pollution, fuel consumption and noise nuisance. Nowadays, some big cities are launching the first electric car-sharing projects to clear traffic jams and enhance urban mobility, as an alternative to the classic public transportation systems. However, there are still some problems to be solved related to energy storage, electric charging and autonomy. In this paper, we present an autonomous docking system for electric vehicles recharging based on an embarked infrared camera performing infrared beacons detection installed in the infrastructure. A visual servoing system coupled with an automatic controller allows the vehicle to dock accurately to the recharging booth in a street parking area. The results show good behavior of the implemented system, which is currently deployed as a real prototype system in the city of Paris.

  5. A Behavior-Based Strategy for Single and Multi-Robot Autonomous Exploration

    Science.gov (United States)

    Cepeda, Jesus S.; Chaimowicz, Luiz; Soto, Rogelio; Gordillo, José L.; Alanís-Reyes, Edén A.; Carrillo-Arce, Luis C.

    2012-01-01

    In this paper, we consider the problem of autonomous exploration of unknown environments with single and multiple robots. This is a challenging task, with several potential applications. We propose a simple yet effective approach that combines a behavior-based navigation with an efficient data structure to store previously visited regions. This allows robots to safely navigate, disperse and efficiently explore the environment. A series of experiments performed using a realistic robotic simulator and a real testbed scenario demonstrate that our technique effectively distributes the robots over the environment and allows them to quickly accomplish their mission in large open spaces, narrow cluttered environments, dead-end corridors, as well as rooms with minimum exits.

  6. Functional Based Adaptive and Fuzzy Sliding Controller for Non-Autonomous Active Suspension System

    Science.gov (United States)

    Huang, Shiuh-Jer; Chen, Hung-Yi

    In this paper, an adaptive sliding controller is developed for controlling a vehicle active suspension system. The functional approximation technique is employed to substitute the unknown non-autonomous functions of the suspension system and release the model-based requirement of sliding mode control algorithm. In order to improve the control performance and reduce the implementation problem, a fuzzy strategy with online learning ability is added to compensate the functional approximation error. The update laws of the functional approximation coefficients and the fuzzy tuning parameters are derived from the Lyapunov theorem to guarantee the system stability. The proposed controller is implemented on a quarter-car hydraulic actuating active suspension system test-rig. The experimental results show that the proposed controller suppresses the oscillation amplitude of the suspension system effectively.

  7. Containment control of networked autonomous underwater vehicles: A predictor-based neural DSC design.

    Science.gov (United States)

    Peng, Zhouhua; Wang, Dan; Wang, Wei; Liu, Lu

    2015-11-01

    This paper investigates the containment control problem of networked autonomous underwater vehicles in the presence of model uncertainty and unknown ocean disturbances. A predictor-based neural dynamic surface control design method is presented to develop the distributed adaptive containment controllers, under which the trajectories of follower vehicles nearly converge to the dynamic convex hull spanned by multiple reference trajectories over a directed network. Prediction errors, rather than tracking errors, are used to update the neural adaptation laws, which are independent of the tracking error dynamics, resulting in two time-scales to govern the entire system. The stability property of the closed-loop network is established via Lyapunov analysis, and transient property is quantified in terms of L2 norms of the derivatives of neural weights, which are shown to be smaller than the classical neural dynamic surface control approach. Comparative studies are given to show the substantial improvements of the proposed new method.

  8. An Image-Based Sensor System for Autonomous Rendez-Vous with Uncooperative Satellites

    CERN Document Server

    Miravet, Carlos; Krouch, Eloise; del Cura, Juan Manuel

    2008-01-01

    In this paper are described the image processing algorithms developed by SENER, Ingenieria y Sistemas to cope with the problem of image-based, autonomous rendez-vous (RV) with an orbiting satellite. The methods developed have a direct application in the OLEV (Orbital Life Extension Extension Vehicle) mission. OLEV is a commercial mission under development by a consortium formed by Swedish Space Corporation, Kayser-Threde and SENER, aimed to extend the operational life of geostationary telecommunication satellites by supplying them control, navigation and guidance services. OLEV is planned to use a set of cameras to determine the angular position and distance to the client satellite during the complete phases of rendez-vous and docking, thus enabling the operation with satellites not equipped with any specific navigational aid to provide support during the approach. The ability to operate with un-equipped client satellites significantly expands the range of applicability of the system under development, compar...

  9. Thruster fault diagnosis method based on Gaussian particle filter for autonomous underwater vehicles

    Directory of Open Access Journals (Sweden)

    Yu-shan Sun

    2016-05-01

    Full Text Available Autonomous Underwater Vehicles (AUVs generally work in complex marine environments. Any fault in AUVs may cause significant losses. Thus, system reliability and automatic fault diagnosis are important. To address the actuator failure of AUVs, a fault diagnosis method based on the Gaussian particle filter is proposed in this study. Six free-space motion equation mathematical models are established in accordance with the actuator configuration of AUVs. The value of the control (moment loss parameter is adopted on the basis of these models to represent underwater vehicle malfunction, and an actuator failure model is established. An improved Gaussian particle filtering algorithm is proposed and is used to estimate the AUV failure model and motion state. Bayes algorithm is employed to perform robot fault detection. The sliding window method is adopted for fault magnitude estimation. The feasibility and validity of the proposed method are verified through simulation experiments and experimental data.

  10. A Behavior-Based Strategy for Single and Multi-Robot Autonomous Exploration

    Directory of Open Access Journals (Sweden)

    José L. Gordillo

    2012-09-01

    Full Text Available In this paper, we consider the problem of autonomous exploration of unknown environments with single and multiple robots. This is a challenging task, with several potential applications. We propose a simple yet effective approach that combines a behavior-based navigation with an efficient data structure to store previously visited regions. This allows robots to safely navigate, disperse and efficiently explore the environment. A series of experiments performed using a realistic robotic simulator and a real testbed scenario demonstrate that our technique effectively distributes the robots over the environment and allows them to quickly accomplish their mission in large open spaces, narrow cluttered environments, dead-end corridors, as well as rooms with minimum exits.

  11. Autonomous Docking Based on Infrared System for Electric Vehicle Charging in Urban Areas

    Directory of Open Access Journals (Sweden)

    Joshué Pérez

    2013-02-01

    Full Text Available Electric vehicles are progressively introduced in urban areas, because of their ability to reduce air pollution, fuel consumption and noise nuisance. Nowadays, some big cities are launching the first electric car-sharing projects to clear traffic jams and enhance urban mobility, as an alternative to the classic public transportation systems. However, there are still some problems to be solved related to energy storage, electric charging and autonomy. In this paper, we present an autonomous docking system for electric vehicles recharging based on an embarked infrared camera performing infrared beacons detection installed in the infrastructure. A visual servoing system coupled with an automatic controller allows the vehicle to dock accurately to the recharging booth in a street parking area. The results show good behavior of the implemented system, which is currently deployed as a real prototype system in the city of Paris.

  12. An algorithm for image clusters detection and identification based on color for an autonomous mobile robot

    Energy Technology Data Exchange (ETDEWEB)

    Uy, D.L.

    1996-02-01

    An algorithm for detection and identification of image clusters or {open_quotes}blobs{close_quotes} based on color information for an autonomous mobile robot is developed. The input image data are first processed using a crisp color fuszzyfier, a binary smoothing filter, and a median filter. The processed image data is then inputed to the image clusters detection and identification program. The program employed the concept of {open_quotes}elastic rectangle{close_quotes}that stretches in such a way that the whole blob is finally enclosed in a rectangle. A C-program is develop to test the algorithm. The algorithm is tested only on image data of 8x8 sizes with different number of blobs in them. The algorithm works very in detecting and identifying image clusters.

  13. Autonomous, Computer-Based Behavioral Health Countermeasure Evaluation at HI-SEAS Mars Analog.

    Science.gov (United States)

    Anderson, Allison P; Fellows, Abigail M; Binsted, Kim A; Hegel, Mark T; Buckey, Jay C

    Living in an isolated, confined environment (ICE) can induce conflict, stress, and depression. Computer-based behavioral health countermeasures are appealing for training and treatment in ICEs because they provide confidentiality and do not require communication with the outside environment. We evaluated the Virtual Space Station (VSS), a suite of interactive computer-delivered psychological training and treatment programs, at the Hawaii Space Exploration Analog and Simulation (HI-SEAS) III expedition. Six subjects (3 male, 3 female) spent 8 mo in group-isolation and used the Conflict, Stress, and Depression modules in the VSS. Survey evaluations, data collected within the program, and postdeployment interviews were collected. This crew dealt with behavioral health issues common to ICEs. The VSS proved to be a valuable resource and was used both as intended, and in unanticipated ways, to help maintain behavioral health. The Conflict and Stress Modules were rated as highly acceptable (1.8 on a 7-point Likert scale). The crew identified a total of 13 stressors and worked on 9 problems through the VSS. Opinions about the modules were highly individualized. Crewmembers identified exercises in the VSS that were applicable and not applicable to their needs. Additional content to improve the program was identified. Autonomous, confidential training and treatment for behavioral health issues will need to be a critical component of long duration spaceflight travel. This work provides an evaluation of such a tool in a relevant ICE. Anderson AP, Fellows AM, Binsted KA, Hegel MT, Buckey JC. Autonomous, computer-based behavioral health countermeasure evaluation at HI-SEAS Mars analog. Aerosp Med Hum Perform. 2016; 87(11):912-920.

  14. The relationship between nature-based tourism and autonomic nervous system function among older adults.

    Science.gov (United States)

    Chang, Liang-Chih

    2014-01-01

    Nature-based tourism has recently become a topic of interest in health research. This study was aimed at examining relationships among nature-based tourism, stress, and the function of the autonomic nervous system (ANS). Three hundred and twenty-two older adults living in Taichung City, Taiwan, were selected as participants. Data were collected by a face-to-face survey that included measures of the frequency of participation in domestic and international nature-based tourism and the stress and ANS function of these participants. The data were analyzed using a path analysis. The results demonstrated that the frequency of participation in domestic nature-based tourism directly contributed to ANS function and that it also indirectly contributed to ANS function through stress reduction. Domestic nature-based tourism can directly and indirectly contribute to ANS function among older adults. Increasing the frequency of participation in domestic nature-based tourism should be considered a critical element of health programs for older adults. © 2014 International Society of Travel Medicine.

  15. The ESP Instruction: A Study Based on the Pattern of Autonomous Inquiry

    Science.gov (United States)

    Zhang, Jianfeng

    2013-01-01

    Autonomous inquiry learning is a kind of learning model, which relies mainly on learners and emphasizes that learners should inquire knowledge actively; moreover, ESP, which emphasizes the combination of language learning and specific purposes learning, is a goal-oriented and well targeted instruction system. Therefore, ESP and autonomous inquiry…

  16. Vision-Based Autonomous Sensor-Tasking in Uncertain Adversarial Environments

    Science.gov (United States)

    2015-01-02

    registration technique with an applica- tion to stereo vision. Proceedings of Imaging Understanding Workshop, pages 121–130, 1981. [17] S. P. Meyn, A...forecast activities, and analyze complex scenes with multiple interacting entities. Specific applications include autonomous aerial surveillance...Specific applications include autonomous aerial surveillance systems that cover broad areas of military operations, camera security sys- tems that cover

  17. Reinforcement Learning with Autonomous Small Unmanned Aerial Vehicles in Cluttered Environments

    Science.gov (United States)

    Tran, Loc; Cross, Charles; Montague, Gilbert; Motter, Mark; Neilan, James; Qualls, Garry; Rothhaar, Paul; Trujillo, Anna; Allen, B. Danette

    2015-01-01

    We present ongoing work in the Autonomy Incubator at NASA Langley Research Center (LaRC) exploring the efficacy of a data set aggregation approach to reinforcement learning for small unmanned aerial vehicle (sUAV) flight in dense and cluttered environments with reactive obstacle avoidance. The goal is to learn an autonomous flight model using training experiences from a human piloting a sUAV around static obstacles. The training approach uses video data from a forward-facing camera that records the human pilot's flight. Various computer vision based features are extracted from the video relating to edge and gradient information. The recorded human-controlled inputs are used to train an autonomous control model that correlates the extracted feature vector to a yaw command. As part of the reinforcement learning approach, the autonomous control model is iteratively updated with feedback from a human agent who corrects undesired model output. This data driven approach to autonomous obstacle avoidance is explored for simulated forest environments furthering autonomous flight under the tree canopy research. This enables flight in previously inaccessible environments which are of interest to NASA researchers in Earth and Atmospheric sciences.

  18. Autonomous frequency stabilization of two extended cavity diode lasers at the potassium wavelength on a sounding rocket

    CERN Document Server

    Dinkelaker, Aline N; Schkolnik, Vladimir; Kenyon, Andrew; Lampmann, Kai; Wenzlawski, André; Windpassinger, Patrick; Hellmig, Ortwin; Wendrich, Thijs; Rasel, Ernst M; Giunta, Michele; Deutsch, Christian; Kürbis, Christian; Smol, Robert; Wicht, Andreas; Krutzik, Markus; Peters, Achim

    2016-01-01

    We have developed, assembled, and flight-proven a stable, compact, and autonomous extended cavity diode laser (ECDL) system designed for atomic physics experiments in space. To that end, two micro-integrated ECDLs at 766.7 nm were frequency stabilized during a sounding rocket flight by means of frequency modulation spectroscopy (FMS) of 39^K and offset locking techniques based on the beat note of the two ECDLs. The frequency stabilization as well as additional hard- and software to test hot redundancy mechanisms were implemented as part of a state-machine, which controlled the experiment completely autonomously throughout the entire flight mission.

  19. Autonomous micromotor based on catalytically pneumatic behavior of balloon-like MnO(x)-graphene crumples.

    Science.gov (United States)

    Chen, Xueli; Wu, Guan; Lan, Tian; Chen, Wei

    2014-07-11

    A novel autonomous micromotor, based on catalytically pneumatic behaviour of balloon-like MnOx-graphene crumples, has been synthesized via an ultrasonic spray pyrolysis method. Through catalytic decomposition of H2O2 into O2, the gas accumulated in a confined space and was released to generate a strong force to push the micromotor.

  20. DualTrust: A Distributed Trust Model for Swarm-Based Autonomic Computing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Maiden, Wendy M.; Dionysiou, Ioanna; Frincke, Deborah A.; Fink, Glenn A.; Bakken, David E.

    2011-02-01

    For autonomic computing systems that utilize mobile agents and ant colony algorithms for their sensor layer, trust management is important for the acceptance of the mobile agent sensors and to protect the system from malicious behavior by insiders and entities that have penetrated network defenses. This paper examines the trust relationships, evidence, and decisions in a representative system and finds that by monitoring the trustworthiness of the autonomic managers rather than the swarming sensors, the trust management problem becomes much more scalable and still serves to protect the swarm. We then propose the DualTrust conceptual trust model. By addressing the autonomic manager’s bi-directional primary relationships in the ACS architecture, DualTrust is able to monitor the trustworthiness of the autonomic managers, protect the sensor swarm in a scalable manner, and provide global trust awareness for the orchestrating autonomic manager.

  1. UAV Formation Flight Based on Nonlinear Model Predictive Control

    Directory of Open Access Journals (Sweden)

    Zhou Chao

    2012-01-01

    Full Text Available We designed a distributed collision-free formation flight control law in the framework of nonlinear model predictive control. Formation configuration is determined in the virtual reference point coordinate system. Obstacle avoidance is guaranteed by cost penalty, and intervehicle collision avoidance is guaranteed by cost penalty combined with a new priority strategy.

  2. Time-of-flight estimation based on covariance models

    NARCIS (Netherlands)

    van der Heijden, Ferdinand; Tuquerres, G.; Regtien, Paulus P.L.

    We address the problem of estimating the time-of-flight (ToF) of a waveform that is disturbed heavily by additional reflections from nearby objects. These additional reflections cause interference patterns that are difficult to predict. The introduction of a model for the reflection in terms of a

  3. Illumination-invariant image matching for autonomous UAV localisation based on optical sensing

    Science.gov (United States)

    Wan, Xue; Liu, Jianguo; Yan, Hongshi; Morgan, Gareth L. K.

    2016-09-01

    This paper presents an UAV (Unmanned Aerial Vehicle) localisation algorithm for its autonomous navigation based on matching between on-board UAV image sequences to a pre-installed reference satellite image. As the UAV images and the reference image are not necessarily taken under the same illumination condition, illumination-invariant image matching is essential. Based on the investigation of illumination-invariant property of Phase Correlation (PC) via mathematical derivation and experiments, we propose a PC based fast and robust illumination-invariant localisation algorithm for UAV navigation. The algorithm accurately determines the current UAV position as well as the next UAV position even the illumination condition of UAV on-board images is different from the reference satellite image. A Dirac delta function based registration quality assessment together with a risk alarming criterion is introduced to enable the UAV to perform self-correction in case the UAV deviates from the planned route. UAV navigation experiments using simulated terrain shading images and remote sensing images have demonstrated a robust high performance of the proposed PC based localisation algorithm under very different illumination conditions resulted from solar motion. The superiority of the algorithm, in comparison with two other widely used image matching algorithms, MI (Mutual Information) and NCC (Normalised Correlation Coefficient), is significant for its high matching accuracy and fast processing speed.

  4. Data assimilation for massive autonomous systems based on a second-order adjoint method

    Science.gov (United States)

    Ito, Shin-ichi; Nagao, Hiromichi; Yamanaka, Akinori; Tsukada, Yuhki; Koyama, Toshiyuki; Kano, Masayuki; Inoue, Junya

    2016-10-01

    Data assimilation (DA) is a fundamental computational technique that integrates numerical simulation models and observation data on the basis of Bayesian statistics. Originally developed for meteorology, especially weather forecasting, DA is now an accepted technique in various scientific fields. One key issue that remains controversial is the implementation of DA in massive simulation models under the constraints of limited computation time and resources. In this paper, we propose an adjoint-based DA method for massive autonomous models that produces optimum estimates and their uncertainties within reasonable computation time and resource constraints. The uncertainties are given as several diagonal elements of an inverse Hessian matrix, which is the covariance matrix of a normal distribution that approximates the target posterior probability density function in the neighborhood of the optimum. Conventional algorithms for deriving the inverse Hessian matrix require O (C N2+N3) computations and O (N2) memory, where N is the number of degrees of freedom of a given autonomous system and C is the number of computations needed to simulate time series of suitable length. The proposed method using a second-order adjoint method allows us to directly evaluate the diagonal elements of the inverse Hessian matrix without computing all of its elements. This drastically reduces the number of computations to O (C ) and the amount of memory to O (N ) for each diagonal element. The proposed method is validated through numerical tests using a massive two-dimensional Kobayashi phase-field model. We confirm that the proposed method correctly reproduces the parameter and initial state assumed in advance, and successfully evaluates the uncertainty of the parameter. Such information regarding uncertainty is valuable, as it can be used to optimize the design of experiments.

  5. Validation of Flight Control Law Based on LFT and Structured Singular Value

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xi; LIU Lin; CHEN Zong-ji; DUAN Hai-bin

    2007-01-01

    The main goal of flight clearance is to use the structured singular value (μ) analysis of the flight control system when some parameters in the system vary in a certain range. As theμ-analysis can only be done on a linear fractional transformation (LFT) model, the first step of flight clearance is to generate the LFT model of the flight control system. In this paper, based on the introduction of basic theory of LFT and μ-analysis, an X-fighter is chosen as an example to utilize the proposed methods. In order to realize the flight clearance process automatically, a novel software package based on MATLAB programming language is developed. The results of simulation experiments validate the feasibility and effectiveness of the novel methods proposed in this paper.

  6. NASA/RAE cooperation on a knowlede based flight status monitor

    Science.gov (United States)

    Butler, G. F.; Duke, E. L.

    1989-01-01

    As part of a US/UK cooperative aeronautical research pragram, a joint activity between the Dryden Flight Research Facility of the NASA Ames Research Center (Ames-Dryden) and the Royal Aerospace Establishment (RAE) on Knowledge Based Systems was established. Under the agreement, a Flight Status Monitor Knowledge base developed at Ames-Dryden was implemented using the real-time IKBS toolkit, MUSE, which was developed in the UK under RAE sponsorship. The Flight Status Monitor is designed to provide on-line aid to the flight test engineer in the interpretation of system health and status by storing expert knowledge of system behavior in an easily accessible form. The background to the cooperation is described and the details of the Flight Status Monitor, the MUSE implementation are presented.

  7. Hand-Eye LRF-Based Iterative Plane Detection Method for Autonomous Robotic Welding

    Directory of Open Access Journals (Sweden)

    Sungmin Lee

    2015-12-01

    Full Text Available This paper proposes a hand-eye LRF-based (laser range finder welding plane-detection method for autonomous robotic welding in the field of shipbuilding. The hand-eye LRF system consists of a 6 DOF manipulator and an LRF attached to the wrist of the manipulator. The welding plane is detected by the LRF with only the wrist's rotation to minimize a mechanical error caused by the manipulator's motion. A position on the plane is determined as an average position of the detected points on the plane, and a normal vector to the plane is determined by applying PCA (principal component analysis to the detected points. In this case, the accuracy of the detected plane is analysed by simulations with respect to the wrist's angle interval and the plane angle. As a result of the analysis, an iterative plane-detection method with the manipulator's alignment motion is proposed to improve the performance of plane detection. For verifying the feasibility and effectiveness of the proposed plane-detection method, experiments are carried out with a prototype of the hand-eye LRF-based system, which consists of a 1 DOF wrist's joint, an LRF system and a rotatable plane. In addition, the experimental results of the PCA-based plane detection method are compared with those of the two representative plane-detection methods, based on RANSAC (RANdom SAmple Consensus and the 3D Hough transform in both accuracy and computation time's points of view.

  8. A learning-based semi-autonomous controller for robotic exploration of unknown disaster scenes while searching for victims.

    Science.gov (United States)

    Doroodgar, Barzin; Liu, Yugang; Nejat, Goldie

    2014-12-01

    Semi-autonomous control schemes can address the limitations of both teleoperation and fully autonomous robotic control of rescue robots in disaster environments by allowing a human operator to cooperate and share such tasks with a rescue robot as navigation, exploration, and victim identification. In this paper, we present a unique hierarchical reinforcement learning-based semi-autonomous control architecture for rescue robots operating in cluttered and unknown urban search and rescue (USAR) environments. The aim of the controller is to enable a rescue robot to continuously learn from its own experiences in an environment in order to improve its overall performance in exploration of unknown disaster scenes. A direction-based exploration technique is integrated in the controller to expand the search area of the robot via the classification of regions and the rubble piles within these regions. Both simulations and physical experiments in USAR-like environments verify the robustness of the proposed HRL-based semi-autonomous controller to unknown cluttered scenes with different sizes and varying types of configurations.

  9. Comparison of Flight Simulators Based on Human Motion Perception Metrics

    Science.gov (United States)

    Valente Pais, Ana R.; Correia Gracio, Bruno J.; Kelly, Lon C.; Houck, Jacob A.

    2015-01-01

    In flight simulation, motion filters are used to transform aircraft motion into simulator motion. When looking for the best match between visual and inertial amplitude in a simulator, researchers have found that there is a range of inertial amplitudes, rather than a single inertial value, that is perceived by subjects as optimal. This zone, hereafter referred to as the optimal zone, seems to correlate to the perceptual coherence zones measured in flight simulators. However, no studies were found in which these two zones were compared. This study investigates the relation between the optimal and the coherence zone measurements within and between different simulators. Results show that for the sway axis, the optimal zone lies within the lower part of the coherence zone. In addition, it was found that, whereas the width of the coherence zone depends on the visual amplitude and frequency, the width of the optimal zone remains constant.

  10. Navigation Behaviors Based on Fuzzy ArtMap Neural Networks for Intelligent Autonomous Vehicles

    Directory of Open Access Journals (Sweden)

    Amine Chohra

    2011-01-01

    Full Text Available The use of hybrid intelligent systems (HISs is necessary to bring the behavior of intelligent autonomous vehicles (IAVs near the human one in recognition, learning, adaptation, generalization, decision making, and action. First, the necessity of HIS and some navigation approaches based on fuzzy ArtMap neural networks (FAMNNs are discussed. Indeed, such approaches can provide IAV with more autonomy, intelligence, and real-time processing capabilities. Second, an FAMNN-based navigation approach is suggested. Indeed, this approach must provide vehicles with capability, after supervised fast stable learning: simplified fuzzy ArtMap (SFAM, to recognize both target-location and obstacle-avoidance situations using FAMNN1 and FAMNN2, respectively. Afterwards, the decision making and action consist of two association stages, carried out by reinforcement trial and error learning, and their coordination using NN3. Then, NN3 allows to decide among the five (05 actions to move towards 30∘, 60∘, 90∘, 120∘, and 150∘. Third, simulation results display the ability of the FAMNN-based approach to provide IAV with intelligent behaviors allowing to intelligently navigate in partially structured environments. Finally, a discussion, dealing with the suggested approach and how its robustness would be if implemented on real vehicle, is given.

  11. Vagal Reactions during Cryoballoon-Based Pulmonary Vein Isolation: A Clue for Autonomic Nervous System Modulation?

    Directory of Open Access Journals (Sweden)

    Michaël Peyrol

    2016-01-01

    Full Text Available Although paroxysmal atrial fibrillation (AF is known to be initiated by rapid firing of pulmonary veins (PV and non-PV triggers, the crucial role of cardiac autonomic nervous system (ANS in the initiation and maintenance of AF has long been appreciated in both experimental and clinical studies. The cardiac intrinsic ANS is composed of ganglionated plexi (GPs, located close to the left atrium-pulmonary vein junctions and a vast network of interconnecting neurons. Ablation strategies aiming for complete PV isolation (PVI remain the cornerstone of AF ablation procedures. However, several observational studies and few randomized studies have suggested that GP ablation, as an adjunctive strategy, might achieve better clinical outcomes in patients undergoing radiofrequency-based PVI for both paroxysmal and nonparoxysmal AF. In these patients, vagal reactions (VR such as vagally mediated bradycardia or asystole are thought to reflect intrinsic cardiac ANS modulation and/or denervation. Vagal reactions occurring during cryoballoon- (CB- based PVI have been previously reported; however, little is known on resulting ANS modulation and/or prevalence and significance of vagal reactions during PVI with the CB technique. We conducted a review of prevalence, putative mechanisms, and significance of VR during CB-based PVI.

  12. Image-based 3D scene analysis for navigation of autonomous airborne systems

    Science.gov (United States)

    Jaeger, Klaus; Bers, Karl-Heinz

    2001-10-01

    In this paper we describe a method for automatic determination of sensor pose (position and orientation) related to a 3D landmark or scene model. The method is based on geometrical matching of 2D image structures with projected elements of the associated 3D model. For structural image analysis and scene interpretation, a blackboard-based production system is used resulting in a symbolic description of image data. Knowledge of the approximated sensor pose measured for example by IMU or GPS enables to estimate an expected model projection used for solving the correspondence problem of image structures and model elements. These correspondences are presupposed for pose computation carried out by nonlinear numerical optimization algorithms. We demonstrate the efficiency of the proposed method by navigation update approaching a bridge scenario and flying over urban area, whereas data were taken with airborne infrared sensors in high oblique view. In doing so we simulated image-based navigation for target engagement and midcourse guidance suited for the concepts of future autonomous systems like missiles and drones.

  13. Relative receiver autonomous integrity monitoring for future GNSS-based aircraft navigation

    Science.gov (United States)

    Gratton, Livio Rafael

    The Global Positioning System (GPS) has enabled reliable, safe, and practical aircraft positioning for en-route and non-precision phases of flight for more than a decade. Intense research is currently devoted to extending the use of Global Navigation Satellite Systems (GNSS), including GPS, to precision approach and landing operations. In this context, this work is focused on the development, analysis, and verification of the concept of Relative Receiver Autonomous Integrity Monitoring (RRAIM) and its potential applications to precision approach navigation. RRAIM fault detection algorithms are developed, and associated mathematical bounds on position error are derived. These are investigated as possible solutions to some current key challenges in precision approach navigation, discussed below. Augmentation systems serving continent-size areas (like the Wide Area Augmentation System or WAAS) allow certain precision approach operations within the covered region. More and better satellites, with dual frequency capabilities, are expected to be in orbit in the mid-term future, which will potentially allow WAAS-like capabilities worldwide with a sparse ground station network. Two main challenges in achieving this goal are (1) ensuring that navigation fault detection functions are fast enough to alert worldwide users of hazardously misleading information, and (2) minimizing situations in which navigation is unavailable because the user's local satellite geometry is insufficient for safe position estimation. Local augmentation systems (implemented at individual airports, like the Local Area Augmentation System or LAAS) have the potential to allow precision approach and landing operations by providing precise corrections to user-satellite range measurements. An exception to these capabilities arises during ionospheric storms (caused by solar activity), when hazardous situations can exist with residual range errors several orders of magnitudes higher than nominal. Until dual

  14. The Autonomous House: A Bio-Hydrogen Based Energy Self-Sufficient Approach

    Directory of Open Access Journals (Sweden)

    Ming-jen Cheng

    2009-04-01

    Full Text Available In the wake of the greenhouse effect and global energy crisis, finding sources of clean, alternative energy and developing everyday life applications have become urgent tasks. This study proposes the development of an "autonomous house" emphasizing the use of modern green energy technology to reduce environmental load, achieve energy autonomy and use energy intelligently in order to create a sustainable, comfortable living environment. The houses' two attributes are: (1 a self-sufficient energy cycle and (2 autonomous energy control to maintain environmental comfort. The autonomous house thus combines energy-conserving, carbon emission-reducing passive design with active elements needed to maintain a comfortable environment.

  15. The autonomous house: a bio-hydrogen based energy self-sufficient approach.

    Science.gov (United States)

    Chen, Shang-Yuan; Chu, Chen-Yeon; Cheng, Ming-Jen; Lin, Chiu-Yue

    2009-04-01

    In the wake of the greenhouse effect and global energy crisis, finding sources of clean, alternative energy and developing everyday life applications have become urgent tasks. This study proposes the development of an "autonomous house" emphasizing the use of modern green energy technology to reduce environmental load, achieve energy autonomy and use energy intelligently in order to create a sustainable, comfortable living environment. The houses' two attributes are: (1) a self-sufficient energy cycle and (2) autonomous energy control to maintain environmental comfort. The autonomous house thus combines energy-conserving, carbon emission-reducing passive design with active elements needed to maintain a comfortable environment.

  16. TORCH - a Cherenkov-based time-of-flight detector

    CERN Document Server

    van Dijk, M W U; Cowie, E N; Cussans, D; D' Ambrosio, C; Forty, R; Frei, C; Gys, T; Piedigrossi, D; Castillo Garcia, L; Fopma, J; Gao, R; Harnew, N; Keri, T

    2014-01-01

    TORCH is an innovative high-precision time-of-flight system to provide particle identification in the difficult intermediate momentum region up to 10 GeV/c. It is also suitable for large-area applications. The detector provides a time-of-flight measurement from the imaging of Cherenkov photons emitted in a 1 cm thick quartz radiator. The photons propagate by total internal reflection to the edge of the quartz plate, where they are focused onto an array of photon detectors at the periphery. A time-of-flight resolution of about 10–15 ps per incident charged particle needs to be achieved for a three sigma kaon–pion separation up to 10 GeV/c momentum for the TORCH located 9.5 m from the interaction point. Given ∼ 30 detected photons per incident charged particle, this requires measuring the time-of-arrival of individual photons to about 70 ps. This paper will describe the design of a TORCH prototype involving a number of ground-breaking and challenging techniques.

  17. Bayesian Network Assessment Method for Civil Aviation Safety Based on Flight Delays

    Directory of Open Access Journals (Sweden)

    Huawei Wang

    2013-01-01

    Full Text Available Flight delays and safety are the principal contradictions in the sound development of civil aviation. Flight delays often come up and induce civil aviation safety risk simultaneously. Based on flight delays, the random characteristics of civil aviation safety risk are analyzed. Flight delays have been deemed to a potential safety hazard. The change rules and characteristics of civil aviation safety risk based on flight delays have been analyzed. Bayesian networks (BN have been used to build the aviation operation safety assessment model based on flight delay. The structure and parameters learning of the model have been researched. By using BN model, some airline in China has been selected to assess safety risk of civil aviation. The civil aviation safety risk of BN model has been assessed by GeNIe software. The research results show that flight delay, which increases the safety risk of civil aviation, can be seen as incremental safety risk. The effectiveness and correctness of the model have been tested and verified.

  18. A Dynamic Bioinspired Neural Network Based Real-Time Path Planning Method for Autonomous Underwater Vehicles.

    Science.gov (United States)

    Ni, Jianjun; Wu, Liuying; Shi, Pengfei; Yang, Simon X

    2017-01-01

    Real-time path planning for autonomous underwater vehicle (AUV) is a very difficult and challenging task. Bioinspired neural network (BINN) has been used to deal with this problem for its many distinct advantages: that is, no learning process is needed and realization is also easy. However, there are some shortcomings when BINN is applied to AUV path planning in a three-dimensional (3D) unknown environment, including complex computing problem when the environment is very large and repeated path problem when the size of obstacles is bigger than the detection range of sensors. To deal with these problems, an improved dynamic BINN is proposed in this paper. In this proposed method, the AUV is regarded as the core of the BINN and the size of the BINN is based on the detection range of sensors. Then the BINN will move with the AUV and the computing could be reduced. A virtual target is proposed in the path planning method to ensure that the AUV can move to the real target effectively and avoid big-size obstacles automatically. Furthermore, a target attractor concept is introduced to improve the computing efficiency of neural activities. Finally, some experiments are conducted under various 3D underwater environments. The experimental results show that the proposed BINN based method can deal with the real-time path planning problem for AUV efficiently.

  19. A Dynamic Bioinspired Neural Network Based Real-Time Path Planning Method for Autonomous Underwater Vehicles

    Directory of Open Access Journals (Sweden)

    Jianjun Ni

    2017-01-01

    Full Text Available Real-time path planning for autonomous underwater vehicle (AUV is a very difficult and challenging task. Bioinspired neural network (BINN has been used to deal with this problem for its many distinct advantages: that is, no learning process is needed and realization is also easy. However, there are some shortcomings when BINN is applied to AUV path planning in a three-dimensional (3D unknown environment, including complex computing problem when the environment is very large and repeated path problem when the size of obstacles is bigger than the detection range of sensors. To deal with these problems, an improved dynamic BINN is proposed in this paper. In this proposed method, the AUV is regarded as the core of the BINN and the size of the BINN is based on the detection range of sensors. Then the BINN will move with the AUV and the computing could be reduced. A virtual target is proposed in the path planning method to ensure that the AUV can move to the real target effectively and avoid big-size obstacles automatically. Furthermore, a target attractor concept is introduced to improve the computing efficiency of neural activities. Finally, some experiments are conducted under various 3D underwater environments. The experimental results show that the proposed BINN based method can deal with the real-time path planning problem for AUV efficiently.

  20. A Monocular Vision Sensor-Based Obstacle Detection Algorithm for Autonomous Robots

    Science.gov (United States)

    Lee, Tae-Jae; Yi, Dong-Hoon; Cho, Dong-Il “Dan”

    2016-01-01

    This paper presents a monocular vision sensor-based obstacle detection algorithm for autonomous robots. Each individual image pixel at the bottom region of interest is labeled as belonging either to an obstacle or the floor. While conventional methods depend on point tracking for geometric cues for obstacle detection, the proposed algorithm uses the inverse perspective mapping (IPM) method. This method is much more advantageous when the camera is not high off the floor, which makes point tracking near the floor difficult. Markov random field-based obstacle segmentation is then performed using the IPM results and a floor appearance model. Next, the shortest distance between the robot and the obstacle is calculated. The algorithm is tested by applying it to 70 datasets, 20 of which include nonobstacle images where considerable changes in floor appearance occur. The obstacle segmentation accuracies and the distance estimation error are quantitatively analyzed. For obstacle datasets, the segmentation precision and the average distance estimation error of the proposed method are 81.4% and 1.6 cm, respectively, whereas those for a conventional method are 57.5% and 9.9 cm, respectively. For nonobstacle datasets, the proposed method gives 0.0% false positive rates, while the conventional method gives 17.6%. PMID:26938540

  1. Autonomous robotic capture of non-cooperative target by adaptive extended Kalman filter based visual servo

    Science.gov (United States)

    Dong, Gangqi; Zhu, Zheng H.

    2016-05-01

    This paper presents a real-time, vision-based algorithm for the pose and motion estimation of non-cooperative targets and its application in visual servo robotic manipulator to perform autonomous capture. A hybrid approach of adaptive extended Kalman filter and photogrammetry is developed for the real-time pose and motion estimation of non-cooperative targets. Based on the pose and motion estimates, the desired pose and trajectory of end-effector is defined and the corresponding desired joint angles of the robotic manipulator are derived by inverse kinematics. A close-loop visual servo control scheme is then developed for the robotic manipulator to track, approach and capture the target. Validating experiments are designed and performed on a custom-built six degrees of freedom robotic manipulator with an eye-in-hand configuration. The experimental results demonstrate the feasibility, effectiveness and robustness of the proposed adaptive extended Kalman filter enabled pose and motion estimation and visual servo strategy.

  2. Autonomic Semantic-Based Context-Aware Platform for Mobile Applications in Pervasive Environments

    Directory of Open Access Journals (Sweden)

    Adel Alti

    2016-09-01

    Full Text Available Currently, the field of smart-* (home, city, health, tourism, etc. is naturally heterogeneous and multimedia oriented. In such a domain, there is an increasing usage of heterogeneous mobile devices, as well as captors transmitting data (IoT. They are highly connected and can be used for many different services, such as to monitor, to analyze and to display information to users. In this context, data management and adaptation in real time are becoming a challenging task. More precisely, at one time, it is necessary to handle in a dynamic, intelligent and transparent framework various data provided by multiple devices with several modalities. This paper presents a Kali-Smart platform, which is an autonomic semantic-based context-aware platform. It is based on semantic web technologies and a middleware providing autonomy and reasoning facilities. Moreover, Kali-Smart is generic and, as a consequence, offers to users a flexible infrastructure where they can easily control various interaction modalities of their own situations. An experimental study has been made to evaluate the performance and feasibility of the proposed platform.

  3. Tool for optimal design and operation of hydrogen storage based autonomous energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Oberschachtsiek, B.; Lemken, D. [ZBT - Duisburg (Germany); Stark, M.; Krost, G. [Duisburg-Essen Univ. (Germany)

    2010-07-01

    Decentralized small scale electricity generation based on renewable energy sources usually necessitates decoupling of volatile power generation and consumption by means of energy storage. Hydrogen has proven as an eligible storage medium for mid- and long-term range, which - when indicated - can be reasonably complemented by accumulator short term storage. The selection of appropriate system components - sources, storage devices and the appertaining peripherals - is a demanding task which affords a high degree of freedom but, on the other hand, has to account for various operational dependencies and restrictions of system components, as well as for conduct of load and generation. An innovative tool facilitates the configuration and dimensioning of renewable energy based power supply systems with hydrogen storage paths, and allows for applying appropriate operation strategies. This tool accounts for the characteristics and performances of relevant power sources, loads, and types of energy storage, and also regards safety rules the energy system has to comply with. In particular, the tool is addressing small, detached and autonomous supply systems. (orig.)

  4. Market-based autonomous resource and application management in private clouds

    KAUST Repository

    Costache, Stefania

    2016-10-12

    High Performance Computing (HPC) clouds need to be efficiently shared between selfish tenants having applications with different resource requirements and Service Level Objectives (SLOs). The main difficulty relies on providing concurrent resource access to such tenants while maximizing the resource utilization. To overcome this challenge, we propose Merkat, a market-based SLO-driven cloud platform. Merkat relies on a market-based model specifically designed for on-demand fine-grain resource allocation to maximize resource utilization and it uses a combination of currency distribution and dynamic resource pricing to ensure proper resource distribution among tenants. To meet the tenant’s SLO, Merkat uses autonomous controllers, which apply adaptation policies that: (i) dynamically tune the application’s provisioned CPU and memory per virtual machine in contention periods, or (ii) dynamically change the number of virtual machines. Our evaluation with simulation and on the Grid’5000 testbed shows that Merkat provides flexible support for different application types and SLOs and good tenant satisfaction compared to existing centralized systems, while the infrastructure resource utilization is improved.

  5. GNSS receiver autonomous integrity monitoring (RAIM) algorithm based on robust estimation

    Institute of Scientific and Technical Information of China (English)

    Yuanxi Yang; Junyi Xu

    2016-01-01

    Integrity is significant for safety-of-life applications. Receiver autonomous integrity monitoring (RAIM) has been developed to provide integrity service for civil aviation. At first, the conventional RAIM algorithm is only suitable for single fault detection, single GNSS constellation. However, multiple satellite failure should be considered when more than one satellite navigation system are adopted. To detect and exclude multi-fault, most cur-rent algorithms perform an iteration procedure considering all possible fault model which lead to heavy computation burden. An alternative RAIM is presented in this paper based on multiple satellite constellations (for example, GPS and BeiDou (BDS) etc.) and robust esti-mation for multi-fault detection and exclusion, which can not only detect multi-failures, but also control the influences of near failure observation. Besides, the RAIM algorithm based on robust estimation is more efficient than the current RAIM algorithm for multiple constellation and multiple faults. Finally, the algorithm is tested by GPS/BeiDou data.

  6. A Monocular Vision Sensor-Based Obstacle Detection Algorithm for Autonomous Robots

    Directory of Open Access Journals (Sweden)

    Tae-Jae Lee

    2016-03-01

    Full Text Available This paper presents a monocular vision sensor-based obstacle detection algorithm for autonomous robots. Each individual image pixel at the bottom region of interest is labeled as belonging either to an obstacle or the floor. While conventional methods depend on point tracking for geometric cues for obstacle detection, the proposed algorithm uses the inverse perspective mapping (IPM method. This method is much more advantageous when the camera is not high off the floor, which makes point tracking near the floor difficult. Markov random field-based obstacle segmentation is then performed using the IPM results and a floor appearance model. Next, the shortest distance between the robot and the obstacle is calculated. The algorithm is tested by applying it to 70 datasets, 20 of which include nonobstacle images where considerable changes in floor appearance occur. The obstacle segmentation accuracies and the distance estimation error are quantitatively analyzed. For obstacle datasets, the segmentation precision and the average distance estimation error of the proposed method are 81.4% and 1.6 cm, respectively, whereas those for a conventional method are 57.5% and 9.9 cm, respectively. For nonobstacle datasets, the proposed method gives 0.0% false positive rates, while the conventional method gives 17.6%.

  7. A Dynamic Bioinspired Neural Network Based Real-Time Path Planning Method for Autonomous Underwater Vehicles

    Science.gov (United States)

    2017-01-01

    Real-time path planning for autonomous underwater vehicle (AUV) is a very difficult and challenging task. Bioinspired neural network (BINN) has been used to deal with this problem for its many distinct advantages: that is, no learning process is needed and realization is also easy. However, there are some shortcomings when BINN is applied to AUV path planning in a three-dimensional (3D) unknown environment, including complex computing problem when the environment is very large and repeated path problem when the size of obstacles is bigger than the detection range of sensors. To deal with these problems, an improved dynamic BINN is proposed in this paper. In this proposed method, the AUV is regarded as the core of the BINN and the size of the BINN is based on the detection range of sensors. Then the BINN will move with the AUV and the computing could be reduced. A virtual target is proposed in the path planning method to ensure that the AUV can move to the real target effectively and avoid big-size obstacles automatically. Furthermore, a target attractor concept is introduced to improve the computing efficiency of neural activities. Finally, some experiments are conducted under various 3D underwater environments. The experimental results show that the proposed BINN based method can deal with the real-time path planning problem for AUV efficiently. PMID:28255297

  8. Neutron Radiography Based Visualization and Profiling of Water Uptake in (Uncracked and Autonomously Healed Cementitious Materials

    Directory of Open Access Journals (Sweden)

    Philip Van den Heede

    2016-04-01

    Full Text Available Given their low tensile strength, cement-based materials are very susceptible to cracking. These cracks serve as preferential pathways for corrosion inducing substances. For large concrete infrastructure works, currently available time-consuming manual repair techniques are not always an option. Often, one simply cannot reach the damaged areas and when making those areas accessible anyway (e.g., by redirecting traffic, the economic impacts involved would be enormous. Under those circumstances, it might be useful to have concrete with an embedded autonomous healing mechanism. In this paper, the effectiveness of incorporating encapsulated high and low viscosity polyurethane-based healing agents to ensure (multiple crack healing has been investigated by means of capillary absorption tests on mortar while monitoring the time-dependent water ingress with neutron radiography. Overall visual interpretation and water front/sample cross-section area ratios as well as water profiles representing the area around the crack and their integrals do not show a preference for the high or low viscosity healing agent. Another observation is that in presence of two cracks, only one is properly healed, especially when using the latter healing agent. Exposure to water immediately after release of the healing agent stimulates the foaming reaction of the polyurethane and ensures a better crack closure.

  9. Research on Roll Stabilizing Based on Energy Optimization for Autonomous Surface Vehicle

    Directory of Open Access Journals (Sweden)

    Hongjian Wang

    2014-01-01

    Full Text Available Considering the case of ASV (autonomous surface vehicle navigating with low speed near water surface, a new method for design of roll motion controller is proposed in order to restrain wave disturbance effectively and improve roll stabilizing performance. Control system design is based on GPC (general predictive control theory and working principle of zero-speed fin stabilizer. Coupling horizontal motion model of ASV is decoupled, and an equivalent transfer function of roll motion is obtained and transformed into a discrete difference equation through inverse Laplace transformation and Euler approximation. Finally, predictive model of GPC, namely, the difference equation of roll motion, is given. GPC algorithm of ASV roll motion is derived from performance index based on roll stabilizing performance and energy consumption used for driving fin stabilizer. In allusion to time-variant parameters in roll motion model, recursive least square method is adopted for parameter estimation. Simulation results of ASV roll motion control show better stabilizing performance and minimized energy consumption improved by self-adaptive GPC.

  10. Auto Landing Process for Autonomous Flying Robot by Using Image Processing Based on Edge Detection

    Directory of Open Access Journals (Sweden)

    Bahram Lavi Sefidgari

    2014-01-01

    Full Text Available In today’s technological life, everyone is quite familiar with the importance of security measures in our lives. So in this regard, many attempts have been made by researchers and one of them is flying robots technology. One well-known usage of flying robot, perhaps, is its capability in security and care measurements which made this device extremely practical, not only for its unmanned movement, but also for the unique manoeuvre during flight over the arbitrary areas. In this research, the automatic landing of a flying robot is discussed. The system is based on the frequent interruptions that is sent from main microcontroller to camera module in order to take images; these images have been distinguished by image processing system based on edge detection, after analysing the image the system can tell whether or not to land on the ground. This method shows better performance in terms of precision as well as experimentally.

  11. A Framework for Evidence-Based Licensure of Adaptive Autonomous Systems

    Science.gov (United States)

    2016-03-01

    Rebecca A. Grier Christopher A. Martin Franklin L. Moses David A. Sparrow INSTITUTE FOR DEFENSE ANALYSES 4850 Mark Center Drive Alexandria, Virginia...Licensure of Adaptive Autonomous Systems David M. Tate Rebecca A. Grier Christopher A. Martin Franklin L. Moses David A. Sparrow ii Executive Summary...autonomous systems. These challenges are exacerbated for adaptive and/or learning systems whose behavior on given inputs can change over time. The

  12. Autonomic neuropathies

    Science.gov (United States)

    Low, P. A.

    1998-01-01

    A limited autonomic neuropathy may underlie some unusual clinical syndromes, including the postural tachycardia syndrome, pseudo-obstruction syndrome, heat intolerance, and perhaps chronic fatigue syndrome. Antibodies to autonomic structures are common in diabetes, but their specificity is unknown. The presence of autonomic failure worsens prognosis in the diabetic state. Some autonomic neuropathies are treatable. Familial amyloid polyneuropathy may respond to liver transplantation. There are anecdotal reports of acute panautonomic neuropathy responding to intravenous gamma globulin. Orthostatic hypotension may respond to erythropoietin or midodrine.

  13. Modelling of XCO2 Surfaces Based on Flight Tests of TanSat Instruments

    Directory of Open Access Journals (Sweden)

    Li Li Zhang

    2016-11-01

    Full Text Available The TanSat carbon satellite is to be launched at the end of 2016. In order to verify the performance of its instruments, a flight test of TanSat instruments was conducted in Jilin Province in September, 2015. The flight test area covered a total area of about 11,000 km2 and the underlying surface cover included several lakes, forest land, grassland, wetland, farmland, a thermal power plant and numerous cities and villages. We modeled the column-average dry-air mole fraction of atmospheric carbon dioxide (XCO2 surface based on flight test data which measured the near- and short-wave infrared (NIR reflected solar radiation in the absorption bands at around 760 and 1610 nm. However, it is difficult to directly analyze the spatial distribution of XCO2 in the flight area using the limited flight test data and the approximate surface of XCO2, which was obtained by regression modeling, which is not very accurate either. We therefore used the high accuracy surface modeling (HASM platform to fill the gaps where there is no information on XCO2 in the flight test area, which takes the approximate surface of XCO2 as its driving field and the XCO2 observations retrieved from the flight test as its optimum control constraints. High accuracy surfaces of XCO2 were constructed with HASM based on the flight’s observations. The results showed that the mean XCO2 in the flight test area is about 400 ppm and that XCO2 over urban areas is much higher than in other places. Compared with OCO-2’s XCO2, the mean difference is 0.7 ppm and the standard deviation is 0.95 ppm. Therefore, the modelling of the XCO2 surface based on the flight test of the TanSat instruments fell within an expected and acceptable range.

  14. Modelling of XCO2 Surfaces Based on Flight Tests of TanSat Instruments

    Science.gov (United States)

    Zhang, Li Li; Yue, Tian Xiang; Wilson, John P.; Wang, Ding Yi; Zhao, Na; Liu, Yu; Liu, Dong Dong; Du, Zheng Ping; Wang, Yi Fu; Lin, Chao; Zheng, Yu Quan; Guo, Jian Hong

    2016-01-01

    The TanSat carbon satellite is to be launched at the end of 2016. In order to verify the performance of its instruments, a flight test of TanSat instruments was conducted in Jilin Province in September, 2015. The flight test area covered a total area of about 11,000 km2 and the underlying surface cover included several lakes, forest land, grassland, wetland, farmland, a thermal power plant and numerous cities and villages. We modeled the column-average dry-air mole fraction of atmospheric carbon dioxide (XCO2) surface based on flight test data which measured the near- and short-wave infrared (NIR) reflected solar radiation in the absorption bands at around 760 and 1610 nm. However, it is difficult to directly analyze the spatial distribution of XCO2 in the flight area using the limited flight test data and the approximate surface of XCO2, which was obtained by regression modeling, which is not very accurate either. We therefore used the high accuracy surface modeling (HASM) platform to fill the gaps where there is no information on XCO2 in the flight test area, which takes the approximate surface of XCO2 as its driving field and the XCO2 observations retrieved from the flight test as its optimum control constraints. High accuracy surfaces of XCO2 were constructed with HASM based on the flight’s observations. The results showed that the mean XCO2 in the flight test area is about 400 ppm and that XCO2 over urban areas is much higher than in other places. Compared with OCO-2’s XCO2, the mean difference is 0.7 ppm and the standard deviation is 0.95 ppm. Therefore, the modelling of the XCO2 surface based on the flight test of the TanSat instruments fell within an expected and acceptable range. PMID:27809272

  15. Architecture for persistent surveillance using mast and UAS-based autonomous sensing with bio-inspired technologies

    Science.gov (United States)

    Burman, Jerry

    2014-06-01

    A sophisticated real time architecture for capturing relevant battlefield information of personnel and terrestrial events from a network of mast based imaging and unmanned aerial systems (UAS) with target detection, tracking, classification and visualization is presented. Persistent surveillance of personnel and vehicles is achieved using a unique spatial and temporally invariant motion detection and tracking algorithm for mast based cameras in combination with aerial remote sensing to autonomously monitor unattended ground based sensor networks. UAS autonomous routing is achieved using bio-inspired algorithms that mimic how bacteria locate nutrients in their environment. Results include field test data, performance and lessons learned. The technology also has application to detecting and tracking low observables (manned and UAS), counter MANPADS, airport bird detection and search and rescue operations.

  16. Development of a fuzzy logic based intelligent system for autonomous guidance of post-stroke rehabilitation exercise.

    Science.gov (United States)

    Huq, Rajibul; Wang, Rosalie; Lu, Elaine; Hebert, Debbie; Lacheray, Hervé; Mihailidis, Alex

    2013-06-01

    This paper presents preliminary studies in developing a fuzzy logic based intelligent system for autonomous post-stroke upper-limb rehabilitation exercise. The intelligent system autonomously varies control parameters to generate different haptic effects on the robotic device. The robotic device is able to apply both resistive and assistive forces for guiding the patient during the exercise. The fuzzy logic based decision-making system estimates muscle fatigue of the patient using exercise performance and generates a combination of resistive and assistive forces so that the stroke survivor can exercise for longer durations with increasing control. The fuzzy logic based system is initially developed using a study with healthy subjects and preliminary results are also presented to validate the developed system with healthy subjects. The next stage of this work will collect data from stroke survivors for further development of the system.

  17. Hand-eye LRF-based Iterative Plane Detection Method for Autonomous Robotic Welding

    Directory of Open Access Journals (Sweden)

    Sungmin Lee

    2015-12-01

    Full Text Available This paper proposes a hand-eye LRF-based (laser range finder welding plane-detection method for autonomous robotic welding in the field of shipbuilding. The hand-eye LRF system consists of a 6 DOF manipulator and an LRF attached to the wrist of the manipulator. The welding plane is detected by the LRF with only the wrist’s rotation to minimize a mechanical error caused by the manipulator’s motion. A position on the plane is determined as an average position of the detected points on the plane, and a normal vector to the plane is determined by applying PCA (principal component analysis to the detected points. In this case, the accuracy of the detected plane is analysed by simulations with respect to the wrist’s angle interval and the plane angle. As a result of the analysis, an iterative plane-detection method with the manipulator’s alignment motion is proposed to improve the performance of plane detection. For verifying the feasibility and effectiveness of the proposed plane-detection method, experiments are carried out with a prototype of the hand-eye LRF-based system, which consists of a 1 DOF wrist’s joint, an LRF system and a rotatable plane. In addition, the experimental results of the PCA-based plane detection method are compared with those of the two representative plane-detection methods, based on RANSAC (RANdom SAmple Consensus and the 3D Hough transform in both accuracy and computation time’s points of view.

  18. An Improved FastSLAM System Based on Distributed Structure for Autonomous Robot Navigation

    Directory of Open Access Journals (Sweden)

    Fu-jun Pei

    2014-01-01

    Full Text Available Fast simultaneous localization and mapping (FastSLAM is an efficient algorithm for autonomous navigation of mobile vehicle. However, FastSLAM must reconfigure the entire vehicle state equation when the feature points change, which causes an exponential growth in quantities of computation and difficulties in isolating potential faults. In order to overcome these limitations, an improved FastSLAM, based on the distributed structure, is developed in this paper. There are two state estimation parts designed in this improved FastSLAM. Firstly, a distributed unscented particle filter is used to avoid reconfiguring the entire system equation in the vehicle state estimation part. Secondly, in the landmarks estimation part, the observation model is designed as a linear one to update the landmarks states by using the linear observation errors. Then, the convergence of the proposed and improved FastSLAM algorithm is given in the sense of mean square. Finally, the simulation results show that the proposed distributed algorithm could reduce the computational complexity with high accuracy and high fault-tolerance performance.

  19. A multiagent system for autonomous operation of islanded microgrids based on a power market environment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H.-M. [Department of Electrical Engineering, University of Incheon/12-1, Sondo-dong, Yeonsu-gu, Incheon, 406-840 (Korea, Republic of); Kinoshita, T. [Graduate School of Information Science, Tohoku University/2-1-1, Katahira, Aoba-ku, Sendai, 980-8577 (Japan); Shin, M.-Ch. [School of Information and Communication Engineering, Sungkyunkwan University/300, Cheoncheon-dong, Jangan-gu, Suwon, Gyeonggi-do, 440-746 (Korea, Republic of)

    2010-12-15

    One of the most important requirements of microgrid operation is to maintain a constant frequency such as 50 Hz or 60 Hz, which is closely related to a power balance between supply and demand. In general, microgrids are connected to power grids and surplus/shortage power of microgrids is traded with power grids. Since islanded microgrids are isolated from any power grids, the decrease in generation or load-shedding can be used to maintain the frequency when a power imbalance between supply and demand occurs. The power imbalance restricts the electricity use of consumers in the case of supply shortage and the power supply of suppliers in the case of supply surplus. Therefore, the islanded microgrid should be operated to reduce power imbalance conditions. Meanwhile, the microgrid is a small-scale power system and the employment of skillful operators for effective operation of its components requires high costs. Therefore, automatic operation of the components is effective realistically. In addition, the components are distributed in the microgrid and their operation should consider their owners' profits. For these reasons, a multiagent system application can be a good alternative for microgrid operation. In this paper, we present a multiagent system for autonomous operation of the islanded microgrid on a power market environment. The proposed multiagent system is designed based on a cooperative operation scheme. We show the functionality and the feasibility of the proposed multiagent system through several tests. (authors)

  20. Flatness-based adaptive fuzzy control of an autonomous submarine model

    Science.gov (United States)

    Rigatos, Gerasimos; Siano, Pierluigi; Raffo, Guilherme

    2015-12-01

    The article presents a differential flatness theory-based method for adaptive control of autonomous submarines. A proof is provided about the differential flatness properties of the submarine's model (having as state variables the vessel's depth and its pitch angle). This also means that all its state variables and its control inputs can be written as differential functions of the flat output. Making use of its differential flatness features, the submarine's dynamic model is transformed into the multivariable linear canonical (Brunovsky) form. In the transformed model, the control inputs consist of unknown nonlinear parts, which are identified with the use of neurofuzzy approximators. The learning rate for these estimators is determined by the requirement the first derivative of the closed-loop's Lyapunov function to be a negative one. Furthermore, with the use of Lyapunov stability analysis it is proven that an H-infinity tracking performance is succeeded for the feedback control loop. This implies enhanced robustness to model uncertainty and to external perturbations. Simulation experiments are carried out to further confirm the efficiency of the proposed adaptive fuzzy control scheme.

  1. PROMOTING STUDENTS’ AUTONOMOUS LEARNING THROUGH ICT BASED LEARNING IN ICP: A CASE STUDY

    Directory of Open Access Journals (Sweden)

    Langgeng Budianto

    2014-12-01

    Full Text Available Promoting Information and Communication Technology (ICT into teaching and learning is a growing area that has attracted many educators’ efforts in recent years. Based on the scope of content covered, ICT integration can happen in three different areas: curriculum, topic, and lesson. The evolution of the ICT has changed the way student or individual learns and communicates. It has created a global social network, where everyone is connected, either directly or indirectly, to each other, especially in exchanging, sharing and learning autonomously. This study attemptted to delineate how the students of International Class Program (ICP at the Faculty of Islamic Education, handle the use of online sources. The students of ICP were selected as the informant. For eliciting information; observation and interview are used in this study. Data are collected by mean of interview guide and field notes. There are 18 students in ICP class. However for the purpose of the study, the researcher selected only three students to participate in the study. The results indicated that three respondents felt positive about using internet to perform task learning experience compared to their experiences in the regular class.

  2. A Robust Indoor Autonomous Positioning System Using Particle Filter Based on ISM Band Wireless Communications

    Science.gov (United States)

    Ikeda, Takeshi; Kawamoto, Mitsuru; Sashima, Akio; Suzuki, Keiji; Kurumatani, Koichi

    In the field of the ubiquitous computing, positioning systems which can provide users' location information have paid attention as an important technical element which can be applied to various services, for example, indoor navigation services, evacuation services, market research services, guidance services, and so on. A lot of researchers have proposed various outdoor and indoor positioning systems. In this paper, we deal with indoor positioning systems. Many conventional indoor positioning systems use expensive infrastructures, because the propagated times of radio waves are used to measure users' positions with high accuracy. In this paper, we propose an indoor autonomous positioning system using radio signal strengths (RSSs) based on ISM band communications. In order to estimate users' positions, the proposed system utilizes a particle filter that is one of the Monte Carlo methods. Because the RSS information is used in the proposed system, the equipments configuring the system are not expensive compared with the conventional indoor positioning systems and it can be installed easily. Moreover, because the particle filter is used to estimate user's position, even if the RSS fluctuates due to, for example, multi-paths, the system can carry out position estimation robustly. We install the proposed system in one floor of a building and carry out some experiments in order to verify the validity of the proposed system. As a result, we confirmed that the average of the estimation errors of the proposed system was about 1.8 m, where the result is enough accuracy for achieving the services mentioned above.

  3. Skills based evaluation of alternative input methods to command a semi-autonomous electric wheelchair.

    Science.gov (United States)

    Rojas, Mario; Ponce, Pedro; Molina, Arturo

    2016-08-01

    This paper presents the evaluation, under standardized metrics, of alternative input methods to steer and maneuver a semi-autonomous electric wheelchair. The Human-Machine Interface (HMI), which includes a virtual joystick, head movements and speech recognition controls, was designed to facilitate mobility skills for severely disabled people. Thirteen tasks, which are common to all the wheelchair users, were attempted five times by controlling it with the virtual joystick and the hands-free interfaces in different areas for disabled and non-disabled people. Even though the prototype has an intelligent navigation control, based on fuzzy logic and ultrasonic sensors, the evaluation was done without assistance. The scored values showed that both controls, the head movements and the virtual joystick have similar capabilities, 92.3% and 100%, respectively. However, the 54.6% capacity score obtained for the speech control interface indicates the needs of the navigation assistance to accomplish some of the goals. Furthermore, the evaluation time indicates those skills which require more user's training with the interface and specifications to improve the total performance of the wheelchair.

  4. Powering autonomous sensors with miniaturized piezoelectric based energy harvesting devices operating at very low frequency

    Science.gov (United States)

    Ferin, G.; Bantignies, C.; Le Khanh, H.; Flesch, E.; Nguyen-Dinh, A.

    2015-12-01

    Harvesting energy from ambient mechanical vibrations is a smart and efficient way to power autonomous sensors and support innovative developments in IoT (Internet of Things), WSN (Wireless Sensor Network) and even implantable medical devices. Beyond the environmental operating conditions, efficiency of such devices is mainly related to energy source properties like the amplitude of vibrations and its spectral contain and some of these applications exhibit a quite low frequency spectrum where harvesting surrounding mechanical energy make sense, typically 5-50Hz for implantable medical devices or 50Hz-150Hz for industrial machines. Harvesting such low frequency vibrations is a challenge since it leads to adapt the resonator geometries to the targeted frequency or to use out-off band indirect harvesting strategies. In this paper we present a piezoelectric based vibrational energy harvesting device (PEH) which could be integrated into a biocompatible package to power implantable sensor or therapeutic medical devices. The presented architecture is a serial bimorph laminated with ultra-thinned (ranging from 15μm to 100μm) outer PZT “skins” that could operate at a “very low frequency”, below 25Hz typically. The core process flow is disclosed and performances highlighted with regards to other low frequency demonstrations.

  5. A Multiagent System for Autonomous Operation of Islanded Microgrids Based on a Power Market Environment

    Directory of Open Access Journals (Sweden)

    Myong-Chul Shin

    2010-12-01

    Full Text Available One of the most important requirements of microgrid operation is to maintain a constant frequency such as 50 Hz or 60 Hz, which is closely related to a power balance between supply and demand. In general, microgrids are connected to power grids and surplus/shortage power of microgrids is traded with power grids. Since islanded microgrids are isolated from any power grids, the decrease in generation or load-shedding can be used to maintain the frequency when a power imbalance between supply and demand occurs. The power imbalance restricts the electricity use of consumers in the case of supply shortage and the power supply of suppliers in the case of supply surplus. Therefore, the islanded microgrid should be operated to reduce power imbalance conditions. Meanwhile, the microgrid is a small-scale power system and the employment of skillful operators for effective operation of its components requires high costs. Therefore, automatic operation of the components is effective realistically. In addition, the components are distributed in the microgrid and their operation should consider their owners’ profits. For these reasons, a multiagent system application can be a good alternative for microgrid operation. In this paper, we present a multiagent system for autonomous operation of the islanded microgrid on a power market environment. The proposed multiagent system is designed based on a cooperative operation scheme. We show the functionality and the feasibility of the proposed multiagent system through several tests.

  6. Cardiac Autonomic Alteration and Metabolic Syndrome: An Ambulatory ECG-based Study in A General Population

    Science.gov (United States)

    Ma, Yan; Tseng, Ping-Huei; Ahn, Andrew; Wu, Ming-Shiang; Ho, Yi-Lwun; Chen, Ming-Fong; Peng, Chung-Kang

    2017-01-01

    Metabolic syndrome (MetS) has been associated with chronic damage to the cardiovascular system. This study aimed to evaluate early stage cardiac autonomic dysfunction with electrocardiography (ECG)-based measures in MetS subjects. During 2012–2013, 175 subjects with MetS and 226 healthy controls underwent ECG recordings of at least 4 hours starting in the morning with ambulatory one-lead ECG monitors. MetS was diagnosed using the criteria defined in the Adult Treatment Panel III, with a modification of waist circumference for Asians. Conventional heart rate variability (HRV) analysis, and complexity index (CI1–20) calculated from 20 scales of entropy (multiscale entropy, MSE), were compared between subjects with MetS and controls. Compared with the healthy controls, subjects with MetS had significantly reduced HRV, including SDNN and pNN20 in time domain, VLF, LF and HF in frequency domain, as well as SD2 in Poincaré analysis. MetS subjects have significantly lower complexity index (CI1–20) than healthy subjects (1.69 ± 0.18 vs. 1.77 ± 0.12, p < 0.001). MetS severity was inversely associated with the CI1–20 (r = −0.27, p < 0.001). MetS is associated with significant alterations in heart rate dynamics, including HRV and complexity. PMID:28290487

  7. 自主空中加油会合过程中飞行制导律设计%Flight guidance law design in process of rendezvous for autonomous aerial refueling

    Institute of Scientific and Technical Information of China (English)

    宋海军; 袁锁中; 刘晓宇

    2014-01-01

    Aiming at the problem of rendezvous for autonomous aerial refueling which is a major issue to be solved current-ly,a method of proportional navigation with terminal angular constraint is used to guide the receiver to flight into refueling dis-trict. The nonlinear guidance algorithm is adopted for the tanker to guide the tanker to flight on the racetrack. A solution to over-cove the nonlinear guidance algorithm failure caused by wind is presented. The concepts of virtual target and virtual tanker is in-troduced to maintain the time synchronize of the receiver and the tanker in rendezvous. A corresponding velocity controller was designed. The simulation platform was built with Matlab/Simulink to verify the rendezvous guidance law for autonomous aerial re-fueling. The simulation results show that the guidance law can satisfy the requirement of rendezvous for autonomous aerial re-fueling.%针对目前自主空中加油亟需解决的会合问题,采用带有末端角约束的比例导引方法,实现了受油机导引进入加油区域,加油机采用非线性制导算法跟踪赛马场跑道线飞行,并给出了有风条件下非线性制导算法可能失效的解决办法。引入虚拟目标和虚拟加油机的概念,保持受油机和加油机在会合上的时间同步,设计了相应的速度控制器。利用Mat-lab/Simulink搭建仿真平台对空中加油会合制导律进行了仿真验证,仿真结果表明设计的制导律能满足自主空中加油的会合要求。

  8. H-infinity based integrated flight-propulsion control design for a STOVL aircraft in transition flight

    Science.gov (United States)

    Garg, Sanjay; Mattern, Duane L.; Bright, Michelle M.; Ouzts, Peter J.

    1990-01-01

    Results are presented from an application of H-infinity control design methodology to a centralized integrated flight/propulsion control (IFPC) system design for a supersonic Short Take-Off and Vertical Landing (STOVL) fighter aircraft in transition flight. The overall design methodology consists of a centralized IFPC controller design with controller partitioning. Only the feedback controller design portion of the methodology is addressed. Design and evaluation vehicle models are summarized, and insight is provided into formulating the H-infinity control problem such that it reflects the IFPC design objectives. The H-infinity controller is shown to provide decoupled command tracking for the design model. The controller order could be significantly reduced by modal residualization of the fast controller modes without any deterioration in performance. A discussion is presented of the areas in which the controller performance needs to be improved, and ways in which these improvements can be achieved within the framework of an H-infinity based linear control design.

  9. Ground-based experiments complement microgravity flight opportunities in the investigation of the effects of space flight on the immune response: is protein kinase C gravity sensitive?

    Science.gov (United States)

    Chapes, S. K.; Woods, K. M.; Armstrong, J. W.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    This manuscript briefly reviews ground-based and flight experiments, discusses how those experiments complement each other, and details how those experiments lead us to speculate about the gravity-sensitive nature of protein kinase C.

  10. Autonomic neuropathy

    DEFF Research Database (Denmark)

    Hilsted, J

    1983-01-01

    The diagnosis of autonomic neuropathy is often difficult to establish, since clinical symptoms generally appear late in the course of the disease, and may be non-specific. A number of recently developed quantifiable and reproducible autonomic nerve function tests are reviewed, with emphasis on th...

  11. Avalanche photodiode based time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ogasawara, Keiichi, E-mail: kogasawara@swri.edu; Livi, Stefano A.; Desai, Mihir I.; Ebert, Robert W.; McComas, David J.; Walther, Brandon C. [Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas 78238 (United States)

    2015-08-15

    This study reports on the performance of Avalanche Photodiodes (APDs) as a timing detector for ion Time-of-Flight (TOF) mass spectroscopy. We found that the fast signal carrier speed in a reach-through type APD enables an extremely short timescale response with a mass or energy independent <2 ns rise time for <200 keV ions (1−40 AMU) under proper bias voltage operations. When combined with a microchannel plate to detect start electron signals from an ultra-thin carbon foil, the APD comprises a novel TOF system that successfully operates with a <0.8 ns intrinsic timing resolution even using commercial off-the-shelf constant-fraction discriminators. By replacing conventional total-energy detectors in the TOF-Energy system, APDs offer significant power and mass savings or an anti-coincidence background rejection capability in future space instrumentation.

  12. Avalanche photodiode based time-of-flight mass spectrometry.

    Science.gov (United States)

    Ogasawara, Keiichi; Livi, Stefano A; Desai, Mihir I; Ebert, Robert W; McComas, David J; Walther, Brandon C

    2015-08-01

    This study reports on the performance of Avalanche Photodiodes (APDs) as a timing detector for ion Time-of-Flight (TOF) mass spectroscopy. We found that the fast signal carrier speed in a reach-through type APD enables an extremely short timescale response with a mass or energy independent <2 ns rise time for <200 keV ions (1-40 AMU) under proper bias voltage operations. When combined with a microchannel plate to detect start electron signals from an ultra-thin carbon foil, the APD comprises a novel TOF system that successfully operates with a <0.8 ns intrinsic timing resolution even using commercial off-the-shelf constant-fraction discriminators. By replacing conventional total-energy detectors in the TOF-Energy system, APDs offer significant power and mass savings or an anti-coincidence background rejection capability in future space instrumentation.

  13. Autonomic neuropathy

    DEFF Research Database (Denmark)

    Hilsted, J

    1980-01-01

    In order to elucidate the physiological significance of autonomic neuropathy in juvenile diabetics, cardiovascular, hormonal and metabolic functions have been investigated in three groups of juvenile diabetics: One group had no signs of neuropathy, one group had presumably slight autonomic...... neuropathy (reduced beat-to-beat variation in heart rate during hyperventilation) and one group had clinically severe autonomic neuropathy, defined by presence of orthostatic hypotension. In all three experimental situations we found sympathetic dysfunction causing cardiovascular and/or hormonal...... maladjustments in patients with autonomic neuropathy. Regarding metabolic functions we found normal responses to graded exercise and insulin-induced hypoglycemia in patients with autonomic neuropathy in spite of blunted catecholamine responses, suggesting increased sensitivity of glycogen stores and adipose...

  14. Self-localization for an autonomous mobile robot based on an omni-directional vision system

    Science.gov (United States)

    Chiang, Shu-Yin; Lin, Kuang-Yu; Chia, Tsorng-Lin

    2013-12-01

    In this study, we designed an autonomous mobile robot based on the rules of the Federation of International Robotsoccer Association (FIRA) RoboSot category, integrating the techniques of computer vision, real-time image processing, dynamic target tracking, wireless communication, self-localization, motion control, path planning, and control strategy to achieve the contest goal. The self-localization scheme of the mobile robot is based on the algorithms featured in the images from its omni-directional vision system. In previous works, we used the image colors of the field goals as reference points, combining either dual-circle or trilateration positioning of the reference points to achieve selflocalization of the autonomous mobile robot. However, because the image of the game field is easily affected by ambient light, positioning systems exclusively based on color model algorithms cause errors. To reduce environmental effects and achieve the self-localization of the robot, the proposed algorithm is applied in assessing the corners of field lines by using an omni-directional vision system. Particularly in the mid-size league of the RobotCup soccer competition, selflocalization algorithms based on extracting white lines from the soccer field have become increasingly popular. Moreover, white lines are less influenced by light than are the color model of the goals. Therefore, we propose an algorithm that transforms the omni-directional image into an unwrapped transformed image, enhancing the extraction features. The process is described as follows: First, radical scan-lines were used to process omni-directional images, reducing the computational load and improving system efficiency. The lines were radically arranged around the center of the omni-directional camera image, resulting in a shorter computational time compared with the traditional Cartesian coordinate system. However, the omni-directional image is a distorted image, which makes it difficult to recognize the

  15. Autonomous UAV-Based Mapping of Large-Scale Urban Firefights

    Energy Technology Data Exchange (ETDEWEB)

    Snarski, S; Scheibner, K F; Shaw, S; Roberts, R S; LaRow, A; Oakley, D; Lupo, J; Neilsen, D; Judge, B; Forren, J

    2006-03-09

    This paper describes experimental results from a live-fire data collect designed to demonstrate the ability of IR and acoustic sensing systems to detect and map high-volume gunfire events from tactical UAVs. The data collect supports an exploratory study of the FightSight concept in which an autonomous UAV-based sensor exploitation and decision support capability is being proposed to provide dynamic situational awareness for large-scale battalion-level firefights in cluttered urban environments. FightSight integrates IR imagery, acoustic data, and 3D scene context data with prior time information in a multi-level, multi-step probabilistic-based fusion process to reliably locate and map the array of urban firing events and firepower movements and trends associated with the evolving urban battlefield situation. Described here are sensor results from live-fire experiments involving simultaneous firing of multiple sub/super-sonic weapons (2-AK47, 2-M16, 1 Beretta, 1 Mortar, 1 rocket) with high optical and acoustic clutter at ranges up to 400m. Sensor-shooter-target configurations and clutter were designed to simulate UAV sensing conditions for a high-intensity firefight in an urban environment. Sensor systems evaluated were an IR bullet tracking system by Lawrence Livermore National Laboratory (LLNL) and an acoustic gunshot detection system by Planning Systems, Inc. (PSI). The results demonstrate convincingly the ability for the LLNL and PSI sensor systems to accurately detect, separate, and localize multiple shooters and the associated shot directions during a high-intensity firefight (77 rounds in 5 sec) in a high acoustic and optical clutter environment with no false alarms. Preliminary fusion processing was also examined that demonstrated an ability to distinguish co-located shooters (shooter density), range to <0.5 m accuracy at 400m, and weapon type.

  16. The control system of an autonomous underwater vehicle

    Directory of Open Access Journals (Sweden)

    Bjørn Jalving

    1995-04-01

    Full Text Available This paper presents the flight control system of an Autonomous Underwater Vehicle (AUV developed at the Norwegian Defence Research Establishment. A mathematical model of the vehicle is derived and discussed. The system is separated into lightly interacting subsystems and three autopilots are designed for steering, diving and speed control. The design of the separate controllers is based on PID techniques. Results from sea trials show robust performance and stability for the autopilot.

  17. Research on flight stability performance of rotor aircraft based on visual servo control method

    Science.gov (United States)

    Yu, Yanan; Chen, Jing

    2016-11-01

    control method based on visual servo feedback is proposed, which is used to improve the attitude of a quad-rotor aircraft and to enhance its flight stability. Ground target images are obtained by a visual platform fixed on aircraft. Scale invariant feature transform (SIFT) algorism is used to extract image feature information. According to the image characteristic analysis, fast motion estimation is completed and used as an input signal of PID flight control system to realize real-time status adjustment in flight process. Imaging tests and simulation results show that the method proposed acts good performance in terms of flight stability compensation and attitude adjustment. The response speed and control precision meets the requirements of actual use, which is able to reduce or even eliminate the influence of environmental disturbance. So the method proposed has certain research value to solve the problem of aircraft's anti-disturbance.

  18. Performance Assessment of Flight Simulator Servo System Based on LQG Performance Benchmark

    Directory of Open Access Journals (Sweden)

    Liu Huibo

    2015-01-01

    Full Text Available Flight simulator is an important application in the field of aerospace as semi-physical simulation equipment. As it requires supreme control precision and stability, it is especially important to search the performance assessment of flight simulator servo system. The traditional researches on flight simulator control performance index is more about dynamic output tracking features but few on input characteristics and effects. Based on Linear Quadratic Gaussian (LQG performance benchmark, this paper makes analyses on high precision flight simulator in three kinds of controller while considering the influences of input and output signals’ effect on controllers. After processing the input and output data, combined with the linear fitting method, we can obtain LQG performance tradeoff curve. Through comparing the controller’s actual performance with the optimal performance, we’ll gain the controller’s control performance index and its potential.

  19. Dynamic autonomous routing technology for IP-based satellite ad hoc networks

    Science.gov (United States)

    Wang, Xiaofei; Deng, Jing; Kostas, Theresa; Rajappan, Gowri

    2014-06-01

    IP-based routing for military LEO/MEO satellite ad hoc networks is very challenging due to network and traffic heterogeneity, network topology and traffic dynamics. In this paper, we describe a traffic priority-aware routing scheme for such networks, namely Dynamic Autonomous Routing Technology (DART) for satellite ad hoc networks. DART has a cross-layer design, and conducts routing and resource reservation concurrently for optimal performance in the fluid but predictable satellite ad hoc networks. DART ensures end-to-end data delivery with QoS assurances by only choosing routing paths that have sufficient resources, supporting different packet priority levels. In order to do so, DART incorporates several resource management and innovative routing mechanisms, which dynamically adapt to best fit the prevailing conditions. In particular, DART integrates a resource reservation mechanism to reserve network bandwidth resources; a proactive routing mechanism to set up non-overlapping spanning trees to segregate high priority traffic flows from lower priority flows so that the high priority flows do not face contention from low priority flows; a reactive routing mechanism to arbitrate resources between various traffic priorities when needed; a predictive routing mechanism to set up routes for scheduled missions and for anticipated topology changes for QoS assurance. We present simulation results showing the performance of DART. We have conducted these simulations using the Iridium constellation and trajectories as well as realistic military communications scenarios. The simulation results demonstrate DART's ability to discriminate between high-priority and low-priority traffic flows and ensure disparate QoS requirements of these traffic flows.

  20. The development of microbatteries based on three-dimensional architectures for autonomous micro devices

    Science.gov (United States)

    Min, Hong-Seok

    2007-12-01

    The goal of fabricating three-dimensional (3D) microbatteries is to improve upon the performance of 2D microbatteries or thin-film batteries by reconfiguring existing materials in a more advanced architecture. 3D battery architectures offer a new approach for miniaturized power sources. These batteries are designed to have a small areal foot print and yet provide sufficient power and energy density to operate autonomous MEMS devices. The more convenient approaches for fabricating such batteries are based on micromachining techniques such as electrodeposition of high aspect ratio metal rods in an array configuration. Three types of three-dimensional microbatteries were fabricated and characterized: Ni-Zn, zinc-air, and Ag-Zn. These different types of microbatteries use different chemistries but all have the common feature of an out-of-plane array of micro-post electrodes. A 3D Ni-Zn microbattery was fabricated and demonstrated proper charge-discharge behavior for the first few cycles. The development of 3D zinc-air microbattery showed high discharge capability under various discharge conditions. Furthermore, performance of 3D zinc-air microbattery was demonstrated by successfully powering an electronic device. During discharge, the 3D zinc-air microbattery exhibited an electrode reaction which formed hollow ZnO electrodes by the Kirkendall effect. This electrode reaction strongly supports the functionality of the 3D microbattery. The fabrication of the Ag-Zn microbattery was accomplished by Ag electrode formation, separator coating, and Zn sedimentation. Due to imperfections in the separator coating, the 3D Ag-Zn microbattery had electrical shorts.

  1. Long-Term, Autonomous Measurement of Atmospheric Carbon Dioxide Using an Ormosil Nanocomposite-Based Optical Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kisholoy Goswami

    2005-10-11

    The goal of this project is to construct a prototype carbon dioxide sensor that can be commercialized to offer a low-cost, autonomous instrument for long-term, unattended measurements. Currently, a cost-effective CO2 sensor system is not available that can perform cross-platform measurements (ground-based or airborne platforms such as balloon and unmanned aerial vehicle (UAV)) for understanding the carbon sequestration phenomenon. The CO2 sensor would support the research objectives of DOE-sponsored programs such as AmeriFlux and the North American Carbon Program (NACP). Global energy consumption is projected to rise 60% over the next 20 years and use of oil is projected to increase by approximately 40%. The combustion of coal, oil, and natural gas has increased carbon emissions globally from 1.6 billion tons in 1950 to 6.3 billion tons in 2000. This figure is expected to reach 10 billon tons by 2020. It is important to understand the fate of this excess CO2 in the global carbon cycle. The overall goal of the project is to develop an accurate and reliable optical sensor for monitoring carbon dioxide autonomously at least for one year at a point remote from the actual CO2 release site. In Phase I of this project, InnoSense LLC (ISL) demonstrated the feasibility of an ormosil-monolith based Autonomous Sensor for Atmospheric CO2 (ASAC) device. All of the Phase I objectives were successfully met.

  2. Nature's Autonomous Oscillators

    Science.gov (United States)

    Mayr, H. G.; Yee, J.-H.; Mayr, M.; Schnetzler, R.

    2012-01-01

    Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock imparts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autonomous oscillators, examples are the quasi-biennial oscillation and bimonthly oscillation of the Earth atmosphere, and the 22-year solar oscillation. The oscillations have been simulated in numerical models without external time dependent source, and in Section 2 we summarize the results. Specifically, we shall discuss the nonlinearities that are involved in generating the oscillations, and the processes that produce the periodicities. In biology, insects have flight muscles, which function autonomously with wing frequencies that far exceed the animals' neural capacity; Stretch-activation of muscle contraction is the mechanism that produces the high frequency oscillation of insect flight, discussed in Section 3. The same mechanism is also invoked to explain the functioning of the cardiac muscle. In Section 4, we present a tutorial review of the cardio-vascular system, heart anatomy, and muscle cell physiology, leading up to Starling's Law of the Heart, which supports our notion that the human heart is also a nonlinear oscillator. In Section 5, we offer a broad perspective of the tenuous links between the fluid dynamical oscillators and the human heart physiology.

  3. Evaluation of distal symmetric polyneuropathy: the role of autonomic testing, nerve biopsy, and skin biopsy (an evidence-based review).

    Science.gov (United States)

    England, J D; Gronseth, G S; Franklin, G; Carter, G T; Kinsella, L J; Cohen, J A; Asbury, A K; Szigeti, K; Lupski, J R; Latov, N; Lewis, R A; Low, P A; Fisher, M A; Herrmann, D; Howard, J F; Lauria, G; Miller, R G; Polydefkis, M; Sumner, A J

    2009-01-01

    Distal symmetric polyneuropathy (DSP) is the most common variety of neuropathy. Since the evaluation of this disorder is not standardized, the available literature was reviewed to provide evidence-based guidelines regarding the role of autonomic testing, nerve biopsy, and skin biopsy for the assessment of polyneuropathy. A literature review using MEDLINE, EMBASE, Science Citation Index, and Current Contents was performed to identify the best evidence regarding the evaluation of polyneuropathy published between 1980 and March 2007. Articles were classified according to a four-tiered level of evidence scheme and recommendations were based on the level of evidence. (1) Autonomic testing may be considered in the evaluation of patients with polyneuropathy to document autonomic nervous system dysfunction (Level B). Such testing should be considered especially for the evaluation of suspected autonomic neuropathy (Level B) and distal small fiber sensory polyneuropathy (SFSN) (Level C). A battery of validated tests is recommended to achieve the highest diagnostic accuracy (Level B). (2) Nerve biopsy is generally accepted as useful in the evaluation of certain neuropathies as in patients with suspected amyloid neuropathy, mononeuropathy multiplex due to vasculitis, or with atypical forms of chronic inflammatory demyelinating polyneuropathy (CIDP). However, the literature is insufficient to provide a recommendation regarding when a nerve biopsy may be useful in the evaluation of DSP (Level U). (3) Skin biopsy is a validated technique for determining intraepidermal nerve fiber (IENF) density and may be considered for the diagnosis of DSP, particularly SFSN (Level C). There is a need for additional prospective studies to define more exact guidelines for the evaluation of polyneuropathy.

  4. Advances in Autonomous Systems for Missions of Space Exploration

    Science.gov (United States)

    Gross, A. R.; Smith, B. D.; Briggs, G. A.; Hieronymus, J.; Clancy, D. J.

    New missions of space exploration will require unprecedented levels of autonomy to successfully accomplish their objectives. Both inherent complexity and communication distances will preclude levels of human involvement common to current and previous space flight missions. With exponentially increasing capabilities of computer hardware and software, including networks and communication systems, a new balance of work is being developed between humans and machines. This new balance holds the promise of meeting the greatly increased space exploration requirements, along with dramatically reduced design, development, test, and operating costs. New information technologies, which take advantage of knowledge-based software, model-based reasoning, and high performance computer systems, will enable the development of a new generation of design and development tools, schedulers, and vehicle and system health monitoring and maintenance capabilities. Such tools will provide a degree of machine intelligence and associated autonomy that has previously been unavailable. These capabilities are critical to the future of space exploration, since the science and operational requirements specified by such missions, as well as the budgetary constraints that limit the ability to monitor and control these missions by a standing army of ground- based controllers. System autonomy capabilities have made great strides in recent years, for both ground and space flight applications. Autonomous systems have flown on advanced spacecraft, providing new levels of spacecraft capability and mission safety. Such systems operate by utilizing model-based reasoning that provides the capability to work from high-level mission goals, while deriving the detailed system commands internally, rather than having to have such commands transmitted from Earth. This enables missions of such complexity and communications distance as are not otherwise possible, as well as many more efficient and low cost

  5. Onboard Processing and Autonomous Operations on the IPEX Cubesat

    Science.gov (United States)

    Chien, Steve; Doubleday, Joshua; Ortega, Kevin; Flatley, Tom; Crum, Gary; Geist, Alessandro; Lin, Michael; Williams, Austin; Bellardo, John; Puig-Suari, Jordi; Stanton, Eric; Yee, Edmond

    2012-01-01

    IPEX is a 1u Cubesat sponsored by NASA Earth Science Technology Office (ESTO), the goals or which are: (1) Flight validate high performance flight computing, (2) Flight validate onboard instrument data processing product generation software, (3) flight validate autonomous operations for instrument processing, (4) enhance NASA outreach and university ties.

  6. An Autonomous Underwater Vehicle Simulation Using Linear Quadratic Servo Based on Open Control Platform

    Directory of Open Access Journals (Sweden)

    Nanang Syahroni

    2012-01-01

    Full Text Available This paper presents an optimal regulator for depth control simulation of an autonomous underwater vehicle (AUV using a new approach of decentralized system environment called open control platform (OCP. Simulation results are presented to demonstrate performance of the proposed method.

  7. Component design and testing for a miniaturised autonomous sensor based on a nanowire materials platform

    NARCIS (Netherlands)

    Fagas, Giorgos; Nolan, Michael; Georgiev, Yordan M.; Yu, Ran; Lotty, Olan; Petkov, Nikolay; Holmes, Justin D.; Jia, Guobin; Eisenhawer, Björn; Gawlik, Annett; Falk, Fritz; Khosropour, Naser; Buitrago, Elizabeth; Fernández-Bolaños Badia, Montserrat; Krummenacher, Francois; Ionescu, Adrian M.; Kayal, Maher; Nightingale, Adrian M.; De Mello, John C; Puik, Erik; Bent, Frank van der; Lafeber, Rik; Ramaneti, Rajesh; Tong, Hien Duy; Rijn, Cees van

    2014-01-01

    From Springer description: "We present the design considerations of an autonomous wireless sensor and discuss the fabrication and testing of the various components including the energy harvester, the active sensing devices and the power management and sensor interface circuits. A common materials pl

  8. Results of NASA/DARPA Automatic Probe and Drogue Refueling Flight Test

    Science.gov (United States)

    Schweikhard, Keith

    2008-01-01

    This slide presentation reviews the flight test from the autonomous airborne refueling system. It includes information on the prototype system that can autonomously perform fueling, including during a turn or mild turbulence, and the autonomous rendezvous capability.

  9. Flight School in the Virtual Environment: Capabilities and Risks of Executing a Simulations-Based Flight Training Program

    Science.gov (United States)

    2012-05-17

    27 Kathy L. Nau, Sara K. Krondak, and Norma L Lewis, "Flight School XXI (FSXXI) Training...October 12, 2011). Nau, Kathy L., Sara K. Krondak, and Norma L Lewis. "Flight School XXI (FSXXI) Training Effectiveness Analysis (TEA)." White

  10. Autonomic dysreflexia

    Science.gov (United States)

    ... most common cause of autonomic dysreflexia (AD) is spinal cord injury. The nervous system of people with AD over-responds to the types of stimulation that do not bother healthy people. Other causes ...

  11. Autonomous search

    CERN Document Server

    Hamadi, Youssef; Saubion, Frédéric

    2012-01-01

    Autonomous combinatorial search (AS) represents a new field in combinatorial problem solving. Its major standpoint and originality is that it considers that problem solvers must be capable of self-improvement operations. This is the first book dedicated to AS.

  12. Intent-Estimation- and Motion-Model-Based Collision Avoidance Method for Autonomous Vehicles in Urban Environments

    Directory of Open Access Journals (Sweden)

    Rulin Huang

    2017-04-01

    Full Text Available Existing collision avoidance methods for autonomous vehicles, which ignore the driving intent of detected vehicles, thus, cannot satisfy the requirements for autonomous driving in urban environments because of their high false detection rates of collisions with vehicles on winding roads and the missed detection rate of collisions with maneuvering vehicles. This study introduces an intent-estimation- and motion-model-based (IEMMB method to address these disadvantages. First, a state vector is constructed by combining the road structure and the moving state of detected vehicles. A Gaussian mixture model is used to learn the maneuvering patterns of vehicles from collected data, and the patterns are used to estimate the driving intent of the detected vehicles. Then, a desirable long-term trajectory is obtained by weighting time and comfort. The long-term trajectory and the short-term trajectory, which are predicted using a constant yaw rate motion model, are fused to achieve an accurate trajectory. Finally, considering the moving state of the autonomous vehicle, collisions can be detected and avoided. Experiments have shown that the intent estimation method performed well, achieving an accuracy of 91.7% on straight roads and an accuracy of 90.5% on winding roads, which is much higher than that achieved by the method that ignores the road structure. The average collision detection distance is increased by more than 8 m. In addition, the maximum yaw rate and acceleration during an evasive maneuver are decreased, indicating an improvement in the driving comfort.

  13. Stability analysis of autonomous space systems in the presence of large disturbances: A Lyapunov-based constrained control strategy.

    Science.gov (United States)

    Mazinan, A H

    2016-03-01

    The research addresses a Lyapunov-based constrained control strategy to deal with the autonomous space system in the presence of large disturbances. The aforementioned autonomous space system under control is first represented through a dynamics model and subsequently the proposed control strategy is fully investigated with a focus on the three-axis detumbling and the corresponding pointing mode control approaches. The three-axis detumbling mode control approach is designed to deal with the unwanted angular rates of the system to be zero, while the saturations of the actuators are taken into consideration. Moreover, the three-axis pointing mode control approach is designed in the similar state to deal with the rotational angles of the system to be desirable. The contribution of the research is mathematically made to propose a control law in connection with a new candidate of Lyapunov function to deal with the rotational angles and the related angular rates of the present autonomous space system with respect to state-of-the-art. A series of experiments are carried out to consider the efficiency of the proposed control strategy, as long as a number of benchmarks are realized in the same condition to verify and guarantee the strategy performance in both modes of control approaches.

  14. Feasibility of Turing-Style Tests for Autonomous Aerial Vehicle "Intelligence"

    Science.gov (United States)

    Young, Larry A.

    2007-01-01

    A new approach is suggested to define and evaluate key metrics as to autonomous aerial vehicle performance. This approach entails the conceptual definition of a "Turing Test" for UAVs. Such a "UAV Turing test" would be conducted by means of mission simulations and/or tailored flight demonstrations of vehicles under the guidance of their autonomous system software. These autonomous vehicle mission simulations and flight demonstrations would also have to be benchmarked against missions "flown" with pilots/human-operators in the loop. In turn, scoring criteria for such testing could be based upon both quantitative mission success metrics (unique to each mission) and by turning to analog "handling quality" metrics similar to the well-known Cooper-Harper pilot ratings used for manned aircraft. Autonomous aerial vehicles would be considered to have successfully passed this "UAV Turing Test" if the aggregate mission success metrics and handling qualities for the autonomous aerial vehicle matched or exceeded the equivalent metrics for missions conducted with pilots/human-operators in the loop. Alternatively, an independent, knowledgeable observer could provide the "UAV Turing Test" ratings of whether a vehicle is autonomous or "piloted." This observer ideally would, in the more sophisticated mission simulations, also have the enhanced capability of being able to override the scripted mission scenario and instigate failure modes and change of flight profile/plans. If a majority of mission tasks are rated as "piloted" by the observer, when in reality the vehicle/simulation is fully- or semi- autonomously controlled, then the vehicle/simulation "passes" the "UAV Turing Test." In this regards, this second "UAV Turing Test" approach is more consistent with Turing s original "imitation game" proposal. The overall feasibility, and important considerations and limitations, of such an approach for judging/evaluating autonomous aerial vehicle "intelligence" will be discussed from a

  15. Executive Cognitive Functioning and Cardiovascular Autonomic Regulation in a Population-Based sample of Working Adults

    Directory of Open Access Journals (Sweden)

    Cecilia Ulrika Dagsdotter Stenfors

    2016-10-01

    Full Text Available Objective: Executive cognitive functioning is essential in private and working life and is sensitive to stress and aging. Cardiovascular (CV health factors are related to cognitive decline and dementia, but there is relatively few studies of the role of CV autonomic regulation, a key component in stress responses and risk factor for cardiovascular disease (CVD, and executive processes. An emerging pattern of results from previous studies suggest that different executive processes may be differentially associated with CV autonomic regulationThe aim was thus to study the associations between multiple measures of CV autonomic regulation and measures of different executive cognitive processes. Method: Participants were 119 healthy working adults (79% women, from the Swedish Longitudinal Occupational Survey of Health. Electrocardiogram was sampled for analysis of heart rate variability measures, including the Standard Deviation of NN, here heart beats (SDNN, root of the mean squares of successive differences (RMSSD, high frequency (HF power band from spectral analyses, and QT variability index (QTVI, a measure of myocardial repolarization patterns. Executive cognitive functioning was measured by 7 neuropsychological tests. The relationships between CV autonomic regulation measures and executive cognitive measures were tested with bivariate and partial correlational analyses, controlling for demographic variables and mental health symptoms.Results: Higher SDNN and RMSSD and lower QTVI were significantly associated with better performance on cognitive tests tapping inhibition, updating, shifting and psychomotor speed. After adjustments for demographic factors however (age being the greatest confounder, only QTVI was clearly associated with these executive tests. No such associations were seen for working memory capacity. Conclusion: Poorer cardiovascular autonomic regulation in terms of lower SDNN & RMSSD and higher QTVI was associated with poorer

  16. Executive Cognitive Functioning and Cardiovascular Autonomic Regulation in a Population-Based Sample of Working Adults

    Science.gov (United States)

    Stenfors, Cecilia U. D.; Hanson, Linda M.; Theorell, Töres; Osika, Walter S.

    2016-01-01

    Objective: Executive cognitive functioning is essential in private and working life and is sensitive to stress and aging. Cardiovascular (CV) health factors are related to cognitive decline and dementia, but there is relatively few studies of the role of CV autonomic regulation, a key component in stress responses and risk factor for cardiovascular disease (CVD), and executive processes. An emerging pattern of results from previous studies suggest that different executive processes may be differentially associated with CV autonomic regulation. The aim was thus to study the associations between multiple measures of CV autonomic regulation and measures of different executive cognitive processes. Method: Participants were 119 healthy working adults (79% women), from the Swedish Longitudinal Occupational Survey of Health. Electrocardiogram was sampled for analysis of heart rate variability (HRV) measures, including the Standard Deviation of NN, here heart beats (SDNN), root of the mean squares of successive differences (RMSSD), high frequency (HF) power band from spectral analyses, and QT variability index (QTVI), a measure of myocardial repolarization patterns. Executive cognitive functioning was measured by seven neuropsychological tests. The relationships between CV autonomic regulation measures and executive cognitive measures were tested with bivariate and partial correlational analyses, controlling for demographic variables, and mental health symptoms. Results: Higher SDNN and RMSSD and lower QTVI were significantly associated with better performance on cognitive tests tapping inhibition, updating, shifting, and psychomotor speed. After adjustments for demographic factors however (age being the greatest confounder), only QTVI was clearly associated with these executive tests. No such associations were seen for working memory capacity. Conclusion: Poorer CV autonomic regulation in terms of lower SDNN and RMSSD and higher QTVI was associated with poorer executive

  17. Autonomic Function in Neurodegenerative Diseases

    DEFF Research Database (Denmark)

    Sørensen, Gertrud Laura; Jennum, Poul Jørgen

    2013-01-01

    , which includes the cardiac centre and controls autonomic functions, and therefore autonomic dysfunction may be experienced early in the disease course. Sleep disturbances are also common non-motor complications of PD, and therefore PD patients undergo polysomnography at the Danish Center for Sleep...... Medicine to assess the sleep disturbances. The aim of this PhD dissertation was to: 1) Develop a method to investigate autonomic changes during sleep in neurodegenerative diseases, and apply this method on PD, iRBD and narcolepsy patients to evaluate the autonomic function in these diseases. 2) Validate...... the method by applying standardized methods to measure the autonomic function based on heart rate variability (HRV) measures. 3) Based on the results, assess the validity of autonomic dysfunction as an early marker of a neurodegenerative disease. 4) Evaluate the influence of hypocretin loss in narcolepsy...

  18. Autonomic healable waterborne organic-inorganic polyurethane hybrids based on aromatic disulfide moieties

    Directory of Open Access Journals (Sweden)

    R. H. Aguirresarobe

    2017-04-01

    Full Text Available Aromatic disulfide dynamic structures were incorporated as chain extenders in waterborne organic-inorganic polyurethane hybrids in order to provide autonomic healable characteristics. The synthesis was carried out following the acetone process methodology and the influence of the introduction of the healing agents in the polymer dispersion stability was analyzed. After the crosslinking process at room temperature, organic-inorganic hybrid films, which presented autonomic healing characteristics, were obtained. These features were evaluated by means of stress-strain tests and the films showed repetitive healing abilities. Thus, the optimum healing time at room temperature (25 °C as well as the influence of different parameters in the healing efficiency, such the aromatic disulfide concentration or the physical properties of the polymer matrix were analyzed.

  19. Model-Based GN and C Simulation and Flight Software Development for Orion Missions beyond LEO

    Science.gov (United States)

    Odegard, Ryan; Milenkovic, Zoran; Henry, Joel; Buttacoli, Michael

    2014-01-01

    For Orion missions beyond low Earth orbit (LEO), the Guidance, Navigation, and Control (GN&C) system is being developed using a model-based approach for simulation and flight software. Lessons learned from the development of GN&C algorithms and flight software for the Orion Exploration Flight Test One (EFT-1) vehicle have been applied to the development of further capabilities for Orion GN&C beyond EFT-1. Continuing the use of a Model-Based Development (MBD) approach with the Matlab®/Simulink® tool suite, the process for GN&C development and analysis has been largely improved. Furthermore, a model-based simulation environment in Simulink, rather than an external C-based simulation, greatly eases the process for development of flight algorithms. The benefits seen by employing lessons learned from EFT-1 are described, as well as the approach for implementing additional MBD techniques. Also detailed are the key enablers for improvements to the MBD process, including enhanced configuration management techniques for model-based software systems, automated code and artifact generation, and automated testing and integration.

  20. Guidance of an autonomous planetary rover based on a short-range hazard detection system

    Science.gov (United States)

    Yerazunis, S. W.; Frederick, D. K.; Hunter, E.; Troiani, N.

    1979-01-01

    The guidance of an autonomous planetary roving vehicle using a scanning laser/multidetector terrain sensor for short-range hazard detection has been simulated. The sensor data are used to model the terrain, thereby providing the information required by a path selection algorithm to control the motion of the rover. These simulation studies are providing the basis for developing both the real-time computer control software and the hardware systems for laboratory and field testing of rover.

  1. Autonomous generator based on Ni-Mn-Ga microactuator as a frequency selective element

    Directory of Open Access Journals (Sweden)

    Barandiaran J.M.

    2013-01-01

    Full Text Available In this work, we suggest the temperature-induced resistivity change at the martensitic transformation in the Ni-Mn-Ga ferromagnetic shape memory alloy as a driving mechanism enabling periodic signal generation. We demonstrated its practical importance by a design of the prototype of a low-frequency autonomous generator. A prominent feature of this new generator is a control of its frequency by the external magnetic field.

  2. Actuator fault diagnosis of autonomous underwater vehicle based on improved Elman neural network

    Institute of Scientific and Technical Information of China (English)

    孙玉山; 李岳明; 张国成; 张英浩; 吴海波

    2016-01-01

    Autonomous underwater vehicles (AUV) work in a complex marine environment. Its system reliability and autonomous fault diagnosis are particularly important and can provide the basis for underwater vehicles to take corresponding security policy in a failure. Aiming at the characteristics of the underwater vehicle which has uncertain system and modeling difficulty, an improved Elman neural network is introduced which is applied to the underwater vehicle motion modeling. Through designing self-feedback connection with fixed gain in the unit connection as well as increasing the feedback of the output layer node, improved Elman network has faster convergence speed and generalization ability. This method for high-order nonlinear system has stronger identification ability. Firstly, the residual is calculated by comparing the output of the underwater vehicle model (estimation in the motion state) with the actual measured values. Secondly, characteristics of the residual are analyzed on the basis of fault judging criteria. Finally, actuator fault diagnosis of the autonomous underwater vehicle is carried out. The results of the simulation experiment show that the method is effective.

  3. Autonomous healing materials based on epoxidized natural rubber and ethylene methacrylic acid ionomers

    Science.gov (United States)

    Arifur Rahman, Md; Penco, Maurizio; Peroni, Isabella; Ramorino, Giorgio; Janszen, Gerardus; Di Landro, Luca

    2012-03-01

    The development of autonomous healing material has an enormous scientific and technological interest. In this context, this research work deals with the investigation of autonomous healing behavior of epoxidized natural rubber (ENR) and its blends with ethylene methacrylic acid ionomers. The autonomous healing behavior of ENR and its blends containing two different ionomers [poly(ethylene-co-methacrylic acid sodium salt) (EMNa) and poly(ethylene-co-methacrylic acid zinc salt) (EMZn)] has been studied by ballistic puncture tests. Interestingly, EMNa/ENR blends exhibit complete healing just after the ballistic test but EMZn/ENR blends do not show full self-repairing. The healing efficiency has been evaluated by optical microscopy and a depressurized air-flow test. The healing mechanism has been investigated by characterizing thermal and mechanical properties of the blends. The chemical structure studied by FTIR and thermal analysis show that the ion content of ionomers and functionality of ENR has a significant influence on the self-healing behavior.

  4. Model-based studies of autonomic and metabolic dysfunction in sleep apnea.

    Science.gov (United States)

    Khoo, Michael C K

    2010-01-01

    Obesity and insulin resistance are highly prevalent in subjects diagnosed with sleep apnea. One factor common to obesity, sleep and insulin resistance is autonomic nervous system dysfunction, in particular, sympathetic overactivity. Although the causal links among these factors are not well understood, it is likely that the vicious cycle of interplay among these factors predisposes to the emergence of "metabolic syndrome", a convergence of obesity, hypertension, insulin resistance and dyslipidemia that is appearing in epidemic proportions in the United States and other countries. This chapter provides an overview of the ongoing experimental and modeling studies in my laboratory aimed at elucidating and quantifying the relationships among autonomic dysfunction, insulin resistance and severity of sleep apnea in overweight subjects. These studies employ a "minimal modeling" approach to extract information characterizing autonomic function from noninvasive cardiorespiratory measurements. We subsequently determine the relationship of these model parameters to the parameters estimated from the Bergman minimal insulin-glucose model using data obtained from the frequently sampled intravenous glucose tolerance test performed on the same individuals.

  5. Autonomic function testing aboard the ISS using “PNEUMOCARD”

    Science.gov (United States)

    Baevsky, R. M.; Funtova, I. I.; Diedrich, A.; Chernikova, A. G.; Drescher, J.; Baranov, V. M.; Tank, J.

    2009-10-01

    Investigations of blood pressure, heart rate (HR), and heart rate variability (HRV) during long term space flights on board the "ISS" have shown characteristic changes of autonomic cardiovascular control. Therefore, alterations of the autonomic nervous system occurring during spaceflight may be responsible for in- and post-flight disturbances. The device "Pneumocard" was developed to further investigate autonomic cardiovascular and respiratory function aboard the ISS. The hard-software diagnostic complex "Pneumocard" was used during in-flight experiment aboard ISS for autonomic function testing. ECG, photoplethysmography, respiration, transthoracic bioimpedance and seismocardiography were assessed in one male cosmonaut (flight lengths six month). Recordings were made prior to the flight, late during flight, and post-flight during spontaneous respiration and controlled respiration at different rates. HR remained stable during flight. The values were comparable to supine measurements on earth. Respiratory frequency and blood pressure decreased during flight. Post flight HR and BP values increased compared to in-flight data exceeding pre-flight values. Cardiac time intervals did not change dramatically during flight. Pulse wave transit time decreased during flight. The maximum of the first time derivative of the impedance cardiogram, which is highly correlated with stroke volume was not reduced in-flight. Our results demonstrate that autonomic function testing aboard the ISS using "Pneumocard" is feasible and generates data of good quality. Despite the decrease in BP, pulse wave transit time was found reduced in space as shown earlier. However, cardiac output did not decrease profoundly in the investigated cosmonaut. Autonomic testing during space flight detects individual changes in cardiovascular control and may add important information to standard medical control. The recent plans to support a flight to Mars, makes these kinds of observations all the more relevant

  6. Stall Recovery in a Centrifuge-Based Flight Simulator With an Extended Aerodynamic Model

    NARCIS (Netherlands)

    Ledegang, W.D.; Groen, E.L.

    2015-01-01

    We investigated the performance of 12 airline pilots in recovering from an asymmetrical stall in a flight simulator featuring an extended aerodynamic model of a transport-category aircraft, and a centrifuge-based motion platform capable of generating enhanced buffet motion and g-cueing. All pilots h

  7. STS-26 crew on fixed based (FB) shuttle mission simulator (SMS) flight deck

    Science.gov (United States)

    1988-01-01

    STS-26 Discovery, Orbiter Vehicle (OV) 103, Commander Frederick H. Hauck (left) and Pilot Richard O. Covey review checklists in their respective stations on the foward flight deck. The STS-26 crew is training in the fixed base (FB) shuttle mission simulator (SMS) located in JSC Mission Simulation and Training Facility Bldg 5.

  8. Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems

    Science.gov (United States)

    Richards, Lance; Parker, Allen; Chan, Patrick

    2014-01-01

    The objective of this task is to investigate, develop, and demonstrate a low-cost swept lasing light source for NASA DFRC's fiber optics sensing system (FOSS) to perform structural health monitoring on current and future aerospace vehicles. This is the regular update of the Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems website.

  9. A Flight-Path Control of Aircraft Based on Required Acceleration Vector

    Science.gov (United States)

    Yoshitani, Naoharu

    This paper presents an automatic flight-path control of aircraft. In the control, a desired flight trajectory is first determined as a sequence of straight lines, arcs and spirals in the three-dimensional space. Commands and command rates of heading and flight-path (climb) angles are then obtained from the desired trajectory. A required acceleration vector of the aircraft is calculated based on the command rates and angle deviations. Desired roll, pitch and yaw rates are then obtained by acceleration controller and are fed to attitude control. The feedback control of acceleration employs conventional PID control technology, without using inverse dynamics of the aircraft, and the attitude control can employ any existing control technologies suitable for the aircraft to be controlled. These make the proposed control relatively simple and easy to implement. Numerical simulations illustrate the effectiveness of the control.

  10. Performance analysis of mini-propellers based on FlightGear

    Science.gov (United States)

    Vogeltanz, Tomáš

    2016-06-01

    This paper presents a performance analysis of three mini-propellers based on the FlightGear flight simulator. Although a basic propeller analysis has to be performed before the use of FlightGear, for a complex and more practical performance analysis, it is advantageous to use a propeller model in cooperation with a particular aircraft model. This approach may determine whether the propeller has sufficient quality in respect of aircraft requirements. In the first section, the software used for the analysis is illustrated. Then, the parameters of the analyzed mini-propellers and the tested UAV are described. Finally, the main section shows and discusses the results of the performance analysis of the mini-propellers.

  11. Cooperative coalition for formation flight scheduling based on incomplete information

    Directory of Open Access Journals (Sweden)

    Meng Linghang

    2015-12-01

    Full Text Available This study analyzes the cooperative coalition problem for formation scheduling based on incomplete information. A multi-agent cooperative coalition framework is developed to optimize the formation scheduling problem in a decentralized manner. The social class differentiation mechanism and role-assuming mechanism are incorporated into the framework, which, in turn, ensures that the multi-agent system (MAS evolves in the optimal direction. Moreover, a further differentiation pressure can be achieved to help MAS escape from local optima. A Bayesian coalition negotiation algorithm is constructed, within which the Harsanyi transformation is introduced to transform the coalition problem based on incomplete information to the Bayesian-equivalent coalition problem based on imperfect information. The simulation results suggest that the distribution of agents’ expectations of other agents’ unknown information approximates to the true distribution after a finite set of generations. The comparisons indicate that the MAS cooperative coalition algorithm produces a significantly better utility and possesses a more effective capability of escaping from local optima than the proposal-engaged marriage algorithm and the Simulated Annealing algorithm.

  12. Aerodynamic flight evaluation analysis and data base update

    Science.gov (United States)

    Boyle, W. W.; Miller, M. S.; Wilder, G. O.; Reheuser, R. D.; Sharp, R. S.; Bridges, G. I.

    1989-01-01

    Research was conducted to determine the feasibility of replacing the Solid Rocket Boosters on the existing Space Shuttle Launch Vehicle (SSLV) with Liquid Rocket Boosters (LRB). As a part of the LRB selection process, a series of wind tunnel tests were conducted along with aero studies to determine the effects of different LRB configurations on the SSLV. Final results were tabulated into increments and added to the existing SSLV data base. The research conducted in this study was taken from a series of wind tunnel tests conducted at Marshall's 14-inch Trisonic Wind Tunnel. The effects on the axial force (CAF), normal force (CNF), pitching moment (CMF), side force (CY), wing shear force (CSR), wing torque moment (CTR), and wing bending moment (CBR) coefficients were investigated for a number of candidate LRB configurations. The aero effects due to LRB protuberances, ET/LRB separation distance, and aft skirts were also gathered from the tests. Analysis was also conducted to investigate the base pressure and plume effects due to the new booster geometries. The test results found in Phases 1 and 2 of wind tunnel testing are discussed and compared. Preliminary LRB lateral/directional data results and trends are given. The protuberance and gap/skirt effects are discussed. The base pressure/plume effects study is discussed and results are given.

  13. Cooperative coalition for formation flight scheduling based on incomplete information

    Institute of Scientific and Technical Information of China (English)

    Meng Linghang; Xu Xiaohao; Zhao Yifei

    2015-01-01

    This study analyzes the cooperative coalition problem for formation scheduling based on incomplete information. A multi-agent cooperative coalition framework is developed to optimize the formation scheduling problem in a decentralized manner. The social class differentiation mech-anism and role-assuming mechanism are incorporated into the framework, which, in turn, ensures that the multi-agent system (MAS) evolves in the optimal direction. Moreover, a further differen-tiation pressure can be achieved to help MAS escape from local optima. A Bayesian coalition nego-tiation algorithm is constructed, within which the Harsanyi transformation is introduced to transform the coalition problem based on incomplete information to the Bayesian-equivalent coali-tion problem based on imperfect information. The simulation results suggest that the distribution of agents’ expectations of other agents’ unknown information approximates to the true distribution after a finite set of generations. The comparisons indicate that the MAS cooperative coalition algo-rithm produces a significantly better utility and possesses a more effective capability of escaping from local optima than the proposal-engaged marriage algorithm and the Simulated Annealing algorithm.

  14. Numerical analysis of tunable parametric terahertz devices based on graphene nanostructures using the projection method and autonomous blocks

    Science.gov (United States)

    Makeeva, G. S.; Golovanov, O. A.; Kouzaev, G. A.

    2017-07-01

    A rigorous mathematical model for graphene-based parametric devices based on the Maxwell`s equations, where the graphene surface conductivity is determined as the nonlinear function on the electric field intensity, is developed. The projection method is applied to solve the 2D nonlinear diffraction boundary problem. Using the computational algorithm based on autonomous blocks with the Floquet channels, a parametric THz device based on a multilayer graphene-dielectric nanostructure is numerically modeled. The numerical analysis shows that this graphene-based device, simulated here at a 14.15 THz, can demonstrate the parametric amplification of signals. The instability regions of the parametric generation in this tunable THz device are calculated depending on the magnitude and frequency of the pumping TEM-wave by computing the determinant of an obtained system of linearized equations.

  15. Model–Based Techniques for Virtual Sensing of Longitudinal Flight Parameters

    Directory of Open Access Journals (Sweden)

    Seren Cédric

    2015-03-01

    Full Text Available Introduction of fly-by-wire and increasing levels of automation significantly improve the safety of civil aircraft, and result in advanced capabilities for detecting, protecting and optimizing A/C guidance and control. However, this higher complexity requires the availability of some key flight parameters to be extended. Hence, the monitoring and consolidation of those signals is a significant issue, usually achieved via many functionally redundant sensors to extend the way those parameters are measured. This solution penalizes the overall system performance in terms of weight, maintenance, and so on. Other alternatives rely on signal processing or model-based techniques that make a global use of all or part of the sensor data available, supplemented by a model-based simulation of the flight mechanics. That processing achieves real-time estimates of the critical parameters and yields dissimilar signals. Filtered and consolidated information is delivered in unfaulty conditions by estimating an extended state vector, including wind components, and can replace failed signals in degraded conditions. Accordingly, this paper describes two model-based approaches allowing the longitudinal flight parameters of a civil A/C to be estimated on-line. Results are displayed to evaluate the performances in different simulated and real flight conditions, including realistic external disturbances and modeling errors.

  16. Vehicle autonomous localization in local area of coal mine tunnel based on vision sensors and ultrasonic sensors.

    Science.gov (United States)

    Xu, Zirui; Yang, Wei; You, Kaiming; Li, Wei; Kim, Young-Il

    2017-01-01

    This paper presents a vehicle autonomous localization method in local area of coal mine tunnel based on vision sensors and ultrasonic sensors. Barcode tags are deployed in pairs on both sides of the tunnel walls at certain intervals as artificial landmarks. The barcode coding is designed based on UPC-A code. The global coordinates of the upper left inner corner point of the feature frame of each barcode tag deployed in the tunnel are uniquely represented by the barcode. Two on-board vision sensors are used to recognize each pair of barcode tags on both sides of the tunnel walls. The distance between the upper left inner corner point of the feature frame of each barcode tag and the vehicle center point can be determined by using a visual distance projection model. The on-board ultrasonic sensors are used to measure the distance from the vehicle center point to the left side of the tunnel walls. Once the spatial geometric relationship between the barcode tags and the vehicle center point is established, the 3D coordinates of the vehicle center point in the tunnel's global coordinate system can be calculated. Experiments on a straight corridor and an underground tunnel have shown that the proposed vehicle autonomous localization method is not only able to quickly recognize the barcode tags affixed to the tunnel walls, but also has relatively small average localization errors in the vehicle center point's plane and vertical coordinates to meet autonomous unmanned vehicle positioning requirements in local area of coal mine tunnel.

  17. Ground-based and in-flight simulator studies of flight characteristics of a twin-fuselage passenger transport airplane during approach and landing

    Science.gov (United States)

    Grantham, W. D.; Smith, P. M.; Neely, W. R., Jr.; Deal, P. L.; Yenni, K. R.

    1985-01-01

    Six-degree-of-freedom ground-based and in-flight simulator studies were conducted to evaluate the low-speed flight characteristics of a twin-fuselage passenger transport airplane and to compare these characteristics with those of a large, single-fuselage (reference) transport configuration similar to the Lockheed C-5A airplane. The primary piloting task was the approach and landing task. The results of this study indicated that the twin-fuselage transport concept had acceptable but unsatisfactory longitudinal and lateral-directional low-speed flight characteristics, and that stability and control augmentation would be required in order to improve the handling qualities. Through the use of rate-command/attitude-hold augmentation in the pitch and roll axes, and the use of several turn coordination features, the handling qualities of the simulated transport were improved appreciably. The in-flight test results showed excellent agreement with those of the six-degree-of-freedom ground-based simulator handling qualities tests. As a result of the in-flight simulation study, a roll-control-induced normal-acceleration criterion was developed. The handling qualities of the augmented twin-fuselage passenger transport airplane exhibited an improvement over the handling characteristics of the reference (single-fuselage) transport.

  18. SEALDH-II: An airborne, autonomous, calibration-free TDLAS Hygrometer. First in-flight results with metrological links to the German Primary Humidity Standards

    Science.gov (United States)

    Buchholz, B.; Ebert, V.

    2014-12-01

    The accuracy and comparability of airborne hygrometers remains under debate often only reaching ±10% under static lab conditions or even >±30% in flight. This often limits atmospheric models as well as other species sensors which need to be corrected for water vapor dilution or cross sensitivity. Further challenges come from the huge dynamic range (2-40000 ppmv), the strong spatial gradients (up to several 1000 ppmv/s). and the difficult and error-prone calibration processes, very often without any direct links to the accurate global metrological water vapor scales, which are defined via national primary humidity generators. To fill this gap and provide "traceable", i.e. metrologically validated, airborne hygrometers we developed the Selective Extractive Airborne Laser Diode Hygrometer, SEALDH, which uses dTDLAS with a special, calibration-free data evaluation to circumvent the need for frequent field calibrations and to ensure high accuracy and comparability by a holistic data quality assurance concept in combination with extensive metrological validations at national primary standards. Thus SEALDH-II can be used in a calibration-free field sensor mode (with an absolute, metrologically defined uncertainty of 4.3% +- 3ppmv). The response time is mainly limited by the gas flow and significantly below 1 sec, yielding precision down to 0.08 ppmv (1σ, 1sec) measured at 600 ppmv and 1000 hPa. Its excellent long-term stability, field transfer standard. SEALDH-II has been recently operated without any failures for over 50 hours on several airborne science missions (DENCHAR, AIRTOSS-I, and AIRTOSS-II). In addition SEALDH participated in the representative, international comparison AquaVIT-II. The performance during these missions and the value of a traceability will be demonstrated and discussed.

  19. Autonomous Household Energy Management Based on a Double Cooperative Game Approach in the Smart Grid

    Directory of Open Access Journals (Sweden)

    Bingtuan Gao

    2015-07-01

    Full Text Available Taking advantage of two-way communication infrastructure and bidirectional energy trading between utility companies and customers in the future smart grid (SG, autonomous energy management programs become crucial to the demand-side management (DSM. Most of the existing autonomous energy management schemes are for the scenario with a single utility company or the scenario with one-way energy trading. In this paper, an autonomous household energy management system with multiple utility companies and multiple residential customers is studied by considering the bidirectional energy trading. To minimize the overall costs of both the utility companies and the residential customers, the energy management system is formulated as a double cooperative game. That is, the interaction among the residential users is formulated as a cooperative game, where the players are the customers and the strategies are the daily schedules of their household appliances; and the interaction among the utility companies is also formulated as a cooperative game, where the players are the suppliers and the strategies are the proportions of the daily total energy they provide for the customers. Without loss of generality, the bidirectional energy trading in the double cooperative game is formulated by allowing plug-in electric vehicles (PEVs to discharge and sell energy back. Two distributed algorithms will be provided to realize the global optimal performance in terms of minimizing the energy costs, which can be guaranteed at the Nash equilibriums of the formulated cooperative games. Finally, simulation results illustrated that the proposed double cooperative game can benefit both the utility companies and residential users significantly.

  20. Autonomous navigation and mapping of mobile robots based on 2D/3D cameras combination

    OpenAIRE

    Joochim, Chanin

    2011-01-01

    Aufgrund der tendenziell zunehmenden Nachfrage an Systemen zur Unterstützung des alltäglichen Lebens gibt es derzeit ein großes Interesse an autonomen Systemen. Autonome Systeme werden in Häusern, Büros, Museen sowie in Fabriken eingesetzt. Sie können verschiedene Aufgaben erledigen, beispielsweise beim Reinigen, als Helfer im Haushalt, im Bereich der Sicherheit und Bildung, im Supermarkt sowie im Empfang als Auskunft, weil sie dazu verwendet werden können, die Verarbeitungszeit zu kontrollie...

  1. The generation of a hyperchaotic system based on a three-dimensional autonomous chaotic system

    Institute of Scientific and Technical Information of China (English)

    Wang Jie-Zhi; Chen Zeng-Qiang; Yuan Zhu-Zhi

    2006-01-01

    This paper reports a new four-dimensional hyperchaotic system obtained by adding a controller to a threedimensional autonomous chaotic system. The new system has two parameters, and each equation of the system has one quadratic cross-product term. Some basic properties of the new system are analysed. The different dynamic behaviours of the new system are studied when the system parameter a or b is varied. The system is hyperchaotic in several different regions of the parameter b. Especially, the two positive Lyapunov exponents are both larger, and the hyperchaotic region is also larger when this system is hyperchaotic in the case of varying a. The hyperchaotic system is analysed by

  2. TWIST SPRINGBACK MEASUREMENT OF AUTONOMOUS UNDERWATER VEHICLE PROPELLER BLADE BASED ON PROFILE DEVIATION

    Directory of Open Access Journals (Sweden)

    Ahmad Baharuddin Abdullah

    2013-01-01

    Full Text Available Geometrical defects that are attributable to springback are among the major defects induced by the sheet metal forming process. Such defects are critical for sections with varying thickness, such as Autonomous Underwater Vehicle (AUV propeller blades. In this study, the springback in the twist-bending of an AA6061 propeller blade was quantified by comparing the targeted and manufactured profiles obtained using the commercial three-dimensional surface measurement technique. The results show that the twist springback becomes larger as the twist angle increases. Similarly, the twist springback increases with increasing deformation ratio.

  3. Time capsule: an autonomous sensor and recorder based on diffusion-reaction.

    Science.gov (United States)

    Gerber, Lukas C; Rosenfeld, Liat; Chen, Yunhan; Tang, Sindy K Y

    2014-11-21

    We describe the use of chemical diffusion and reaction to record temporally varying chemical information as spatial patterns without the need for external power. Diffusion of chemicals acts as a clock, while reactions forming immobile products possessing defined optical properties perform sensing and recording functions simultaneously. The spatial location of the products reflects the history of exposure to the detected substances of interest. We refer to our device as a time capsule and show an initial proof of principle in the autonomous detection of lead ions in water.

  4. Physics Based Model for Online Fault Detection in Autonomous Cryogenic Loading System

    Science.gov (United States)

    Kashani, Ali; Devine, Ekaterina Viktorovna P; Luchinsky, Dmitry Georgievich; Smelyanskiy, Vadim; Sass, Jared P.; Brown, Barbara L.; Patterson-Hine, Ann

    2013-01-01

    We report the progress in the development of the chilldown model for rapid cryogenic loading system developed at KSC. The nontrivial characteristic feature of the analyzed chilldown regime is its active control by dump valves. The two-phase flow model of the chilldown is approximated as one-dimensional homogeneous fluid flow with no slip condition for the interphase velocity. The model is built using commercial SINDAFLUINT software. The results of numerical predictions are in good agreement with the experimental time traces. The obtained results pave the way to the application of the SINDAFLUINT model as a verification tool for the design and algorithm development required for autonomous loading operation.

  5. Autonomous optical navigation for interplanetary exploration based on information of earth-moon

    Institute of Scientific and Technical Information of China (English)

    吴伟仁; 田玉龙; 黄翔宇

    2003-01-01

    The image elements of earth-center and moon-center are obtained by processing the images of earthand moon, these image elements in combination with the inertial attitude information and the moon ephemerisare utilized to obtain the probe initial position relative to earth, and the Levenberg-Marquardt algorithm is usedto determine the accurate probe position relative to earth, and the probe orbit relative to earth is estimated by u-sing the extended Kalman filter. The autonomous optical navigation algorithm is validated using the digital simu-lation.

  6. Aircraft Configuration and Flight Crew Compliance with Procedures While Conducting Flight Deck Based Interval Management (FIM) Operations

    Science.gov (United States)

    Shay, Rick; Swieringa, Kurt A.; Baxley, Brian T.

    2012-01-01

    Flight deck based Interval Management (FIM) applications using ADS-B are being developed to improve both the safety and capacity of the National Airspace System (NAS). FIM is expected to improve the safety and efficiency of the NAS by giving pilots the technology and procedures to precisely achieve an interval behind the preceding aircraft by a specific point. Concurrently but independently, Optimized Profile Descents (OPD) are being developed to help reduce fuel consumption and noise, however, the range of speeds available when flying an OPD results in a decrease in the delivery precision of aircraft to the runway. This requires the addition of a spacing buffer between aircraft, reducing system throughput. FIM addresses this problem by providing pilots with speed guidance to achieve a precise interval behind another aircraft, even while flying optimized descents. The Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR) human-in-the-loop experiment employed 24 commercial pilots to explore the use of FIM equipment to conduct spacing operations behind two aircraft arriving to parallel runways, while flying an OPD during high-density operations. This paper describes the impact of variations in pilot operations; in particular configuring the aircraft, their compliance with FIM operating procedures, and their response to changes of the FIM speed. An example of the displayed FIM speeds used incorrectly by a pilot is also discussed. Finally, this paper examines the relationship between achieving airline operational goals for individual aircraft and the need for ATC to deliver aircraft to the runway with greater precision. The results show that aircraft can fly an OPD and conduct FIM operations to dependent parallel runways, enabling operational goals to be achieved efficiently while maintaining system throughput.

  7. Integrated Systems Health Management as an Enabler for Condition Based Maintenance and Autonomic Logistics

    Science.gov (United States)

    2015-09-17

    inspections reveal faults that require correction or if there is an in flight emergency (IFE). Following the identification of faults, the aircraft...An overview of structural health monitoring for steel bridges. Practice Periodical on Structural Design and Construction. Nelms, D. (2008, August 1

  8. On Web-based English Autonomous Learning%基于网络环境下的英语自主性学习

    Institute of Scientific and Technical Information of China (English)

    王娜

    2012-01-01

    To improve students' web-based autonomous learning ability is an important task in quality education field.Based on the analysis of the influence of the web-based autonomous learning,and with the characteristics of English autonomous learning,this paper analyses web-based English autonomous learning mode,and summarizes the problems it exists and puts forward suggestions for the web-based English autonomous learning.%通过网络提高学生的自主学习能力,是素质教育研究的一个重要课题。文章在分析网络环境对英语自主性学习产生影响的基础上,结合网络环境下英语自主性学习的特点,探讨了网络环境下英语自主性学习的模式,并分析和总结了网络环境下的英语自主性学习存在的问题及其建议。

  9. H-infinity based integrated flight/propulsion control design for a STOVL aircraft in transition flight

    Science.gov (United States)

    Garg, Sanjay; Mattern, Duane L.; Bright, Michelle; Ouzts, Peter

    1990-01-01

    This paper presents results from an application of H(infinity) control design methodology to a centralized integrated flight/propulsion control (IFPC) system design for a supersonic STOVL fighter aircraft in transition flight. The overall design methodology consists of a centralized IFPC design with controller partitioning. Design and evaluation vehicle models are summarized, and insight is provided into formulating the H(infinity) control problem such that it reflects the IFPC design objective. The H(infinity) controller is shown to provide decoupled command tracking for the design model. The controller order could be significantly reduced by modal residualization of the fast controller modes without any deterioration in performance.

  10. Numerical simulation of base flow of a long range flight vehicle

    Science.gov (United States)

    Saha, S.; Rathod, S.; Chandra Murty, M. S. R.; Sinha, P. K.; Chakraborty, Debasis

    2012-05-01

    Numerical exploration of base flow of a long range flight vehicle is presented for different flight conditions. Three dimensional Navier-Stokes equations are solved along with k-ɛ turbulence model using commercial CFD software. Simulation captured all essential flow features including flow separation at base shoulder, shear layer formation at the jet boundary, recirculation at the base region etc. With the increase in altitude, the plume of the rocket exhaust is seen to bulge more and more and caused more intense free stream and rocket plume interaction leading to higher gas temperature in the base cavity. The flow field in the base cavity is investigated in more detail, which is found to be fairly uniform at different instant of time. Presence of the heat shield is seen to reduce the hot gas entry to the cavity region due to different recirculation pattern in the base region. Computed temperature history obtained from conjugate heat transfer analysis is found to compare very well with flight measured data.

  11. Vision-based semi-autonomous outdoor robot system to reduce soldier workload

    Science.gov (United States)

    Richardson, Al; Rodgers, Michael H.

    2001-09-01

    Sensors and computational capability have not reached the point to enable small robots to navigate autonomously in unconstrained outdoor environments at tactically useful speeds. This problem is greatly reduced, however, if a soldier can lead the robot through terrain that he knows it can traverse. An application of this concept is a small pack-mule robot that follows a foot soldier over outdoor terrain. The solder would be responsible to avoid situations beyond the robot's limitations when encountered. Having learned the route, the robot could autonomously retrace the path carrying supplies and munitions. This would greatly reduce the soldier's workload under normal conditions. This paper presents a description of a developmental robot sensor system using low-cost commercial 3D vision and inertial sensors to address this application. The robot moves at fast walking speed and requires only short-range perception to accomplish its task. 3D-feature information is recorded on a composite route map that the robot uses to negotiate its local environment and retrace the path taught by the soldier leader.

  12. Achieving safe autonomous landings on Mars using vision-based approaches

    Science.gov (United States)

    Pien, Homer

    1992-03-01

    Autonomous landing capabilities will be critical to the success of planetary exploration missions, and in particular to the exploration of Mars. Past studies have indicated that the probability of failure associated with open-loop landings is unacceptably high. Two approaches to achieving autonomous landings with higher probabilities of success are currently under analysis. If a landing site has been certified as hazard free, then navigational aids can be used to facilitate a precision landing. When only limited surface knowledge is available and landing areas cannot be certified as hazard free, then a hazard detection and avoidance approach can be used, in which the vehicle selects hazard free landing sites in real-time during its descent. Issues pertinent to both approaches, including sensors and algorithms, are presented. Preliminary results indicate that one promising approach to achieving high accuracy precision landing is to correlate optical images of the terrain acquired during the terminal descent phase with a reference image. For hazard detection scenarios, a sensor suite comprised of a passive intensity sensor and a laser ranging sensor appears promising as a means of achieving robust landings.

  13. Autonomous robot navigation based on the evolutionary multi-objective optimization of potential fields

    Science.gov (United States)

    Herrera Ortiz, Juan Arturo; Rodríguez-Vázquez, Katya; Padilla Castañeda, Miguel A.; Arámbula Cosío, Fernando

    2013-01-01

    This article presents the application of a new multi-objective evolutionary algorithm called RankMOEA to determine the optimal parameters of an artificial potential field for autonomous navigation of a mobile robot. Autonomous robot navigation is posed as a multi-objective optimization problem with three objectives: minimization of the distance to the goal, maximization of the distance between the robot and the nearest obstacle, and maximization of the distance travelled on each field configuration. Two decision makers were implemented using objective reduction and discrimination in performance trade-off. The performance of RankMOEA is compared with NSGA-II and SPEA2, including both decision makers. Simulation experiments using three different obstacle configurations and 10 different routes were performed using the proposed methodology. RankMOEA clearly outperformed NSGA-II and SPEA2. The robustness of this approach was evaluated with the simulation of different sensor masks and sensor noise. The scheme reported was also combined with the wavefront-propagation algorithm for global path planning.

  14. Effect of Above Real Time Training and Post Flight Feedback in Training of Novice Pilots in a PC-Based Flight Simulator

    Science.gov (United States)

    Khan, M. Javed; Rossi, Marcia; Heath, Bruce E.; Ali, Syed firasat; Crane, Peter; Knighten, Tremaine; Culpepper, Christi

    2003-01-01

    The use of Post-Flight Feedback (PFFB) and Above Real-Time Training (ARTT) while training novice pilots to perform a coordinated level turn on a PC-based flight simulator was investigated. One group trained at 1.5 ARTT followed by an equal number of flights at 2.0 ARTT; the second group experienced Real Time Training (RTT). The total number of flights for both groups was equal. Each group was further subdivided into two groups one of which was provided PFFB while the other was not. Then, all participants experienced two challenging evaluation missions in real time. Performance was assessed by comparing root-mean-square error in bank-angle and altitude. Participants in the 1.512.0 ARTT No-PFFB sequence did not show improvement in performance across training sessions. An ANOVA on performance in evaluation flights found that the PFFB groups performed significantly better than those with No-PFFB. Also, the RTT groups performed significantly better than the ARTT groups. Data from two additional groups trained under a 2.011.5 ARTT PFFB and No-PFFB regimes were collected and combined with data from the previously Trainers, Real-time simulation, Personal studied groups and reanalyzed to study the computers, Man-in-the-loop simulation influence of sequence. An ANOVA on test trials found no significant effects between groups. Under training situations involving ARTT we recommend that appropriate PFFB be provided.

  15. Autonomous Evolutionary Information Systems

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Traditional information systems are passive, i.e., data orknowledge is created , retrieved, modified, updated, and deleted only in response to operations issued by users or application programs, and the systems only can execute queries or t ransactions explicitly submitted by users or application programs but have no ab ility to do something actively by themselves. Unlike a traditional information system serving just as a storehouse of data or knowledge and working passively a ccording to queries or transactions explicitly issued by users and application p rograms, an autonomous evolutionary information system serves as an autonomous a nd evolutionary partner of its users that discovers new knowledge from its datab ase or knowledge-base autonomously, cooperates with its users in solving proble m s actively by providing the users with advices, and has a certain mechanism to i mprove its own state of “knowing” and ability of “working”. This paper semi nall y defines what is an autonomous evolutionary information system, explain why aut onomous evolutionary information systems are needed, and presents some new issue s, fundamental considerations, and research directions in design and development of autonomous evolutionary information systems.

  16. Toward a Model-Based Approach to Flight System Fault Protection

    Science.gov (United States)

    Day, John; Murray, Alex; Meakin, Peter

    2012-01-01

    Fault Protection (FP) is a distinct and separate systems engineering sub-discipline that is concerned with the off-nominal behavior of a system. Flight system fault protection is an important part of the overall flight system systems engineering effort, with its own products and processes. As with other aspects of systems engineering, the FP domain is highly amenable to expression and management in models. However, while there are standards and guidelines for performing FP related analyses, there are not standards or guidelines for formally relating the FP analyses to each other or to the system hardware and software design. As a result, the material generated for these analyses are effectively creating separate models that are only loosely-related to the system being designed. Development of approaches that enable modeling of FP concerns in the same model as the system hardware and software design enables establishment of formal relationships that has great potential for improving the efficiency, correctness, and verification of the implementation of flight system FP. This paper begins with an overview of the FP domain, and then continues with a presentation of a SysML/UML model of the FP domain and the particular analyses that it contains, by way of showing a potential model-based approach to flight system fault protection, and an exposition of the use of the FP models in FSW engineering. The analyses are small examples, inspired by current real-project examples of FP analyses.

  17. An experimental analysis of situation awareness for cockpit display interface evaluation based on flight simulation

    Institute of Scientific and Technical Information of China (English)

    Wei Hengyang; Zhuang Damin; Wanyan Xiaoru; Wang Qun

    2013-01-01

    Aircraft cockpit display interface (CDI) is one of the most important human-machine interfaces for information perceiving.During the process of aircraft design,situation awareness (SA) is frequently considered to improve the design,as the CDI must provide enough SA for the pilot to maintain the flight safety.In order to study the SA in the pilot-aircraft system,a cockpit flight simulation environment is built up,which includes a virtual instrument panel,a flight visual display and the corresponding control system.Based on the simulation environment,a human-in-the-loop experiment is designed to measure the SA by the situation awareness global assessment technique (SAGAT).Through the experiment,the SA degrees and heart rate (HR) data of the subjects are obtained,and the SA levels under different CDI designs are analyzed.The results show that analyzing the SA can serve as an objective way to evaluate the design of CDI,which could be proved from the consistent HR data.With this method,evaluations of the CDI design are performed in the experimental flight simulation environment,and optimizations could be guided through the analysis.

  18. Robust Predictive Functional Control for Flight Vehicles Based on Nonlinear Disturbance Observer

    Directory of Open Access Journals (Sweden)

    Yinhui Zhang

    2015-01-01

    Full Text Available A novel robust predictive functional control based on nonlinear disturbance observer is investigated in order to address the control system design for flight vehicles with significant uncertainties, external disturbances, and measurement noise. Firstly, the nonlinear longitudinal dynamics of the flight vehicle are transformed into linear-like state-space equations with state-dependent coefficient matrices. And then the lumped disturbances are considered in the linear structure predictive model of the predictive functional control to increase the precision of the predictive output and resolve the intractable mismatched disturbance problem. As the lumped disturbances cannot be derived or measured directly, the nonlinear disturbance observer is applied to estimate the lumped disturbances, which are then introduced to the predictive functional control to replace the unknown actual lumped disturbances. Consequently, the robust predictive functional control for the flight vehicle is proposed. Compared with the existing designs, the effectiveness and robustness of the proposed flight control are illustrated and validated in various simulation conditions.

  19. Parameter Estimation from Near Stall Flight Data using Conventional and Neural-based Methods

    Directory of Open Access Journals (Sweden)

    S. Saderla

    2016-12-01

    Full Text Available The current research paper is an endeavour to estimate the parameters from near stall flight data of manned and unmanned research flight vehicles using conventional and neural based methods. For an aircraft undergoing stall, the aerodynamic model at these high angles of attack becomes non linear due to the influence of unsteady, transient and flow separation phenomena. In order to address these issues the Kirchhoff’s flow separation theory was used to incorporate the nonlinearity in the aerodynamic model in terms of flow separation point and stall characteristic parameters. The classical Maximum Likelihood (MLE method and Neural Gauss-Newton (NGN method have been employed to estimate the nonlinear parameters of two manned and one unmanned research aircrafts. The estimated static stall parameter and the break point, for the flight vehicles under consideration, were observed to be consistent from both the methods. Moreover the efficacy of the methods is also evident from the consistent estimates of post stall hysteresis time constant. It can also be inferred that the considered quasi steady model is able to adequately capture the drag and pitching moment coefficients in the post stall regime. The confidence in these estimates have been significantly enhanced with the observed lower values of Cramer-Rao bounds. Further the estimated nonlinear parameters were validated by performing a proof of match exercise for the considered flight vehicles. Interestingly the NGN method, which doesn’t involve solving equations of motion, was able to perform on a par with the MLE method.

  20. 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.

  1. H/OZ: PFD and Collaborative Flight Control System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — With aircraft automation increasingly able to control flight autonomously, situational awareness and engagement of the crew can suffer. To improve aviation safety...

  2. Simulation and Analysis of Autonomous Time Synchronization Based on Asynchronism Two-way Inter-satellite Link

    Science.gov (United States)

    Fang, L.; Yang, X. H.; Sun, B. Q.; Qin, W. J.; Kong, Y.

    2013-09-01

    The measurement of the inter-satellite link is one of the key techniques in the autonomous operation of satellite navigation system. Based on the asynchronism inter-satellite two-way measurement mode in GPS constellation, the reduction formula of the inter-satellite time synchronization is built in this paper. Moreover, the corrective method of main systematic errors is proposed. Inter-satellite two-way time synchronization is simulated on the basis of IGS (International GNSS Service) precise ephemeris. The impacts of the epoch domestication of asynchronism inter-satellite link pseudo-range, the initial orbit, and the main systematic errors on satellite time synchronization are analyzed. Furthermore, the broadcast clock error of each satellite is calculated by the ``centralized'' inter-satellite autonomous time synchronization. Simulation results show that the epoch domestication of asynchronism inter-satellite link pseudo-range and the initial orbit have little impact on the satellite clock errors, and thus they needn't be taken into account. The errors caused by the relativistic effect and the asymmetry of path travel have large impact on the satellite clock errors. These should be corrected with theoretical formula. Compared with the IGS precise clock error, the root mean square of the broadcast clock error of each satellite is about 0.4 ns.

  3. Multi-UAVs Formation Autonomous Control Method Based on RQPSO-FSM-DMPC

    Directory of Open Access Journals (Sweden)

    Shao-lei Zhou

    2016-01-01

    Full Text Available For various threats in the enemy defense area, in order to achieve covert penetration and implement effective combat against enemy, the unmanned aerial vehicles formation needs to be reconfigured in the process of penetration; the mutual collision avoidance problems and communication constraint problems among the formation also need to be considered. By establishing the virtual-leader formation model, this paper puts forward distributed model predictive control and finite state machine formation manager. Combined with distributed cooperative strategy establishing the formation reconfiguration cost function, this paper proposes that adopting the revised quantum-behaved particle swarm algorithm solves the cost function, and it is compared with the result which is solved by particle swarm algorithm. Simulation result shows that this algorithm can control multiple UAVs formation autonomous reconfiguration effectively and achieve covert penetration safely.

  4. Nonlinear Reduced-Order Observer-Based Predictive Control for Diving of an Autonomous Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Xuliang Yao

    2017-01-01

    Full Text Available The attitude control and depth tracking issue of autonomous underwater vehicle (AUV are addressed in this paper. By introducing a nonsingular coordinate transformation, a novel nonlinear reduced-order observer (NROO is presented to achieve an accurate estimation of AUV’s state variables. A discrete-time model predictive control with nonlinear model online linearization (MPC-NMOL is applied to enhance the attitude control and depth tracking performance of AUV considering the wave disturbance near surface. In AUV longitudinal control simulation, the comparisons have been presented between NROO and full-order observer (FOO and also between MPC-NMOL and traditional NMPC. Simulation results show the effectiveness of the proposed method.

  5. Construction of Fuzzy Map for Autonomous Mobile Robots Based on Fuzzy Confidence Model

    Directory of Open Access Journals (Sweden)

    Jung-Fu Hou

    2014-01-01

    Full Text Available This paper presents the use of fuzzy models to explicitly consider sensor uncertainty and finite resolution in solving the SLAM (simultaneous localization and mapping problem for autonomous mobile robots. The approach establishes fuzzy confidence models in describing occupied obstacles and available space. The problem is transformed into an optimization task of minimizing the alignment error between newly scanned local fuzzy maps and selected parts of a developing global fuzzy map. In aligning local fuzzy maps into a global fuzzy map, we developed a prediction strategy to crop the most potential part from the sensed local fuzzy maps to be overlapped with the global fuzzy map. A mobile vehicle equipped with a laser range finder, the Hokuyo URG-04LX, is used to demonstrate the procedure of fuzzy map building. Experimental results show that the proposed architecture is effective in generating a comprehensive global fuzzy map, which is suitable for both human comprehension and path design during real-time navigation.

  6. A Proxy-Based Approach to Enhancing the Autonomic Behavior in Composite Services

    Directory of Open Access Journals (Sweden)

    Onyeka Ezenwoye

    2008-05-01

    Full Text Available Web services paradigm is allowing applications to electronically interact with one another over the Internet. The business process execution language (BPEL takes this interaction to a higher level of abstraction by enabling the development of aggregate Web services. However, the autonomous and distributed nature of the partner services in an aggregate Web service present unique challenges to the reliability of the composite services. In this paper, we present an approach where existing BPEL processes are automatically instrumented, so that when one or more of their partner services do not provide satisfactory service (e.g., because of a service being overwhelmed, crashed, or because of a network outage, the request for service is redirected to a proxy Web service, where the failed or slow services are replaced by substitute services.

  7. Autonomous quantum refrigerator in a circuit QED architecture based on a Josephson junction

    Science.gov (United States)

    Hofer, Patrick P.; Perarnau-Llobet, Martí; Brask, Jonatan Bohr; Silva, Ralph; Huber, Marcus; Brunner, Nicolas

    2016-12-01

    An implementation of a small quantum absorption refrigerator in a circuit QED architecture is proposed. The setup consists of three harmonic oscillators coupled to a Josephson junction. The refrigerator is autonomous in the sense that it does not require any external control for cooling, but only thermal contact between the oscillators and heat baths at different temperatures. In addition, the setup features a built-in switch, which allows the cooling to be turned on and off. If timing control is available, this enables the possibility for coherence-enhanced cooling. Finally, we show that significant cooling can be achieved with experimentally realistic parameters and that our setup should be within reach of current technology.

  8. Geostatistical Prediction of Ocean Outfall Plume Characteristics Based on an Autonomous Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Patrícia Alexandra Gregório Ramos

    2013-07-01

    Full Text Available Geostatistics has been successfully used to analyse and characterize the spatial variability of environmental properties. Besides providing estimated values at unsampled locations, geostatistics measures the accuracy of the estimate, which is a significant advantage over traditional methods used to assess pollution. This work uses universal block kriging to model and map the spatial distribution of salinity measurements gathered by an Autonomous Underwater Vehicle in a sea outfall monitoring campaign. The aim is to distinguish the effluent plume from the receiving waters, characterizing its spatial variability in the vicinity of the discharge and estimating dilution. The results demonstrate that geostatistical methodology can provide good estimates of the dispersion of effluents, which are valuable in assessing the environmental impact and managing sea outfalls. Moreover, since accurate measurements of the plume’s dilution are rare, these studies may be very helpful in the future to validate dispersion models.

  9. Competitiveness of Characteristic Agriculture in Guangxi Zhuang Autonomous Region Based on Explanatory Indicators

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The five explanatory indicators of the competitiveness of characteristic agriculture are the agricultural science and technology,the cultural quality of agricultural labor force,the agricultural infrastructure,the resource endowment,and the agricultural management scale.According to these explanatory indicators,competitiveness of characteristic agriculture is relatively strong in Guangxi Zhuang Autonomous Region of China,which is mainly reflected in the resource advantage,irrigation degree,and road construction level.However,the agricultural technology level,the cultural quality of agricultural labor force,the agricultural mechanization,and the agricultural management scale have relatively poor competitiveness.Therefore,more attention should be paid in these aspects,in order to improve the competitiveness of characteristic agriculture in Guangxi.

  10. 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.

  11. Vision-Based Autonomous Underwater Vehicle Navigation in Poor Visibility Conditions Using a Model-Free Robust Control

    Directory of Open Access Journals (Sweden)

    Ricardo Pérez-Alcocer

    2016-01-01

    Full Text Available This paper presents a vision-based navigation system for an autonomous underwater vehicle in semistructured environments with poor visibility. In terrestrial and aerial applications, the use of visual systems mounted in robotic platforms as a control sensor feedback is commonplace. However, robotic vision-based tasks for underwater applications are still not widely considered as the images captured in this type of environments tend to be blurred and/or color depleted. To tackle this problem, we have adapted the lαβ color space to identify features of interest in underwater images even in extreme visibility conditions. To guarantee the stability of the vehicle at all times, a model-free robust control is used. We have validated the performance of our visual navigation system in real environments showing the feasibility of our approach.

  12. A Compound Fuzzy Disturbance Observer Based on Sliding Modes and Its Application on Flight Simulator

    OpenAIRE

    Yunjie Wu; Youmin Liu; Dapeng Tian

    2013-01-01

    A compound fuzzy disturbance observer based on sliding modes is developed, and its application on flight simulator is presented. Fuzzy disturbance observer (FDO) is an effective method in nonlinear control. However, traditional FDO is confined to monitor dynamic disturbance, and the frequency bandwidth of the system is restricted. Sliding mode control (SMC) compensates the high-frequency component of disturbance while it is limited by the chattering phenomenon. The proposed method uses the sl...

  13. Autonomous component carrier selection

    DEFF Research Database (Denmark)

    Garcia, Luis Guilherme Uzeda; Pedersen, Klaus; Mogensen, Preben

    2009-01-01

    in local areas, basing our study case on LTE-Advanced. We present extensive network simulation results to demonstrate that a simple and robust interference management scheme, called autonomous component carrier selection allows each cell to select the most attractive frequency configuration; improving...

  14. Autonomous Forest Fire Detection

    NARCIS (Netherlands)

    Breejen, E. den; Breuers, M.; Cremer, F.; Kemp, R.A.W.; Roos, M.; Schutte, K.; Vries, J.S. de

    1998-01-01

    Forest fire detection is a very important issue in the pre-suppression process. Timely detection allows the suppression units to reach the fire in its initial stages and this will reduce the suppression costs considerably. The autonomous forest fire detection principle is based on temporal contrast

  15. Does Virtual Reality-based Kinect Dance Training Paradigm Improve Autonomic Nervous System Modulation in Individuals with Chronic Stroke?

    Science.gov (United States)

    Sampaio, Luciana Maria Malosá; Subramaniam, Savitha; Arena, Ross; Bhatt, Tanvi

    2016-01-01

    Background Physical inactivity and low resting heart rate variability (HRV) are associated with an increased cardiovascular deconditioning, risk of secondary stroke and mortality. Aerobic dance is a multidimensional physical activity and recent research supports its application as a valid alternative cardiovascular training. Furthermore, technological advances have facilitated the emergence of new approaches for exercise training holding promise, especially those methods that integrate rehabilitation with virtual gaming. Objective The purpose of this study was to evaluate cardiac autonomic modulation in individuals with chronic stroke post-training using a virtual reality – based aerobic dance training paradigm. Methods Eleven community-dwelling individuals with hemiparetic stroke [61.7( ± 4.3) years] received a virtual reality-based dance paradigm for 6 weeks using the commercially available Kinect dance video game “Just Dance 3.” The training was delivered in a high-intensity tapering method with the first two weeks consisting of 5 sessions/week, next two weeks of 3 sessions/week and last two weeks of 2 sessions/week, with a total of 20 sessions. Data obtained for HRV analysis pre- and post-intervention consists of HRV for ten minutes in (1) supine resting position; (2) quiet standing. High-frequency (HF) power measures as indicators of cardiac parasympathetic activity, low-frequency (LF) power of parasympathetic-sympathetic balance and LF/HF of sympatho-vagal balance were calculated. YMCA submaximal cycle Ergometer test was used to acquire VO2 max pre- and post-intervention. Changes in physical activity during dance training were assessed using Omran HJ-321 Tri-Axis Pedometer. Results After training, participants demonstrated a significant improvement in autonomic modulation in the supine position, indicating an improvement in LF=48.4 ( ± 20.1) to 40.3 ( ± 8.0), p=0.03; HF=51.5 ( ± 19) to 59.7 ( ± 8), p= 0.02 and LF/HF=1.6 ( ± 1.9) to 0.8 ( ± 0

  16. Cybersecurity for aerospace autonomous systems

    Science.gov (United States)

    Straub, Jeremy

    2015-05-01

    High profile breaches have occurred across numerous information systems. One area where attacks are particularly problematic is autonomous control systems. This paper considers the aerospace information system, focusing on elements that interact with autonomous control systems (e.g., onboard UAVs). It discusses the trust placed in the autonomous systems and supporting systems (e.g., navigational aids) and how this trust can be validated. Approaches to remotely detect the UAV compromise, without relying on the onboard software (on a potentially compromised system) as part of the process are discussed. How different levels of autonomy (task-based, goal-based, mission-based) impact this remote characterization is considered.

  17. A ToF-camera as a 3D Vision Sensor for Autonomous Mobile Robotics

    OpenAIRE

    Sobers Lourdu Xavier Francis; Sreenatha G. Anavatti; Matthew Garratt; Hyunbgo Shim

    2015-01-01

    The aim of this paper is to deploy a time-of-flight (ToF) based photonic mixer device (PMD) camera on an Autonomous Ground Vehicle (AGV) whose overall target is to traverse from one point to another in hazardous and hostile environments employing obstacle avoidance without human intervention. The hypothesized approach of applying a ToF Camera for an AGV is a suitable approach to autonomous robotics because, as the ToF camera can provide three-dimensional (3D) information at a low computationa...

  18. Does Virtual Reality-based Kinect Dance Training Paradigm Improve Autonomic Nervous System Modulation in Individuals with Chronic Stroke?

    Science.gov (United States)

    Sampaio, Luciana Maria Malosá; Subramaniam, Savitha; Arena, Ross; Bhatt, Tanvi

    2016-10-01

    Physical inactivity and low resting heart rate variability (HRV) are associated with an increased cardiovascular deconditioning, risk of secondary stroke and mortality. Aerobic dance is a multidimensional physical activity and recent research supports its application as a valid alternative cardiovascular training. Furthermore, technological advances have facilitated the emergence of new approaches for exercise training holding promise, especially those methods that integrate rehabilitation with virtual gaming. The purpose of this study was to evaluate cardiac autonomic modulation in individuals with chronic stroke post-training using a virtual reality - based aerobic dance training paradigm. Eleven community-dwelling individuals with hemiparetic stroke [61.7( ± 4.3) years] received a virtual reality-based dance paradigm for 6 weeks using the commercially available Kinect dance video game "Just Dance 3." The training was delivered in a high-intensity tapering method with the first two weeks consisting of 5 sessions/week, next two weeks of 3 sessions/week and last two weeks of 2 sessions/week, with a total of 20 sessions. Data obtained for HRV analysis pre- and post-intervention consists of HRV for ten minutes in (1) supine resting position; (2) quiet standing. High-frequency (HF) power measures as indicators of cardiac parasympathetic activity, low-frequency (LF) power of parasympathetic-sympathetic balance and LF/HF of sympatho-vagal balance were calculated. YMCA submaximal cycle Ergometer test was used to acquire VO2 max pre- and post-intervention. Changes in physical activity during dance training were assessed using Omran HJ-321 Tri-Axis Pedometer. After training, participants demonstrated a significant improvement in autonomic modulation in the supine position, indicating an improvement in LF=48.4 ( ± 20.1) to 40.3 ( ± 8.0), p=0.03; HF=51.5 ( ± 19) to 59.7 ( ± 8), p= 0.02 and LF/HF=1.6 ( ± 1.9) to 0.8 ( ± 0.26), p=0.05]. Post-training the participants

  19. Sonar-based iceberg-relative navigation for autonomous underwater vehicles

    Science.gov (United States)

    Kimball, Peter; Rock, Stephen

    2011-06-01

    Iceberg-relative navigation for autonomous underwater vehicles (AUVs) will enable a new mode of data collection for studies of free-floating icebergs. Compared to current data collection methods, autonomous underwater vehicles offer substantially expanded coverage area and continuous sampling. However, because icebergs translate and rotate through inertial space, standard vehicle navigation methods which rely on inertial sensors are unable to provide iceberg-relative position estimates. Presented here is a new iceberg-relative vehicle navigation technique which is an extension of existing work in terrain-relative navigation. The technique comprises a mapping step and localization step, each of which is modified here to account for the translation and the rotation of free-floating icebergs. In the mapping step, the AUV circumnavigates the iceberg at a sequence of constant depths, collecting multibeam sonar imagery of the iceberg's submerged surface. A map is then generated in post-processing by projecting these sonar data from their corresponding vehicle positions (accounting for iceberg motion) in a frame that is fixed to the iceberg. Overlapping sonar data from the beginning and end of a circumnavigation provide the information necessary to enforce self-consistency of the iceberg map. In the localization step, the AUV uses the previously generated map to determine its position and orientation with respect to the iceberg by correlating incoming sonar ranges with the map. The estimator works by maintaining explicit estimates not only of the vehicle position and orientation, but also of the iceberg translation and rotation rates through inertial space. Results from a proof-of-concept field demonstration of this new iceberg-relative AUV navigation technique prove the feasibility of both generating a self-consistent three-dimensional map of a moving iceberg and localizing a vehicle's position with respect to that iceberg. The data for the experiment were collected

  20. A Compound Fuzzy Disturbance Observer Based on Sliding Modes and Its Application on Flight Simulator

    Directory of Open Access Journals (Sweden)

    Yunjie Wu

    2013-01-01

    Full Text Available A compound fuzzy disturbance observer based on sliding modes is developed, and its application on flight simulator is presented. Fuzzy disturbance observer (FDO is an effective method in nonlinear control. However, traditional FDO is confined to monitor dynamic disturbance, and the frequency bandwidth of the system is restricted. Sliding mode control (SMC compensates the high-frequency component of disturbance while it is limited by the chattering phenomenon. The proposed method uses the sliding mode technique to deal with the uncompensated dynamic equivalent disturbance. The switching gain of sliding mode control designed according to the error of disturbance estimation is a small value. Therefore, the proposal also helps to decrease the chattering. The validity of the proposal method is confirmed by experiments on flight simulator.

  1. Postural instability and motion sickness in a fixed-based flight simulator.

    Science.gov (United States)

    Stoffregen, T A; Hettinger, L J; Haas, M W; Roe, M M; Smart, L J

    2000-01-01

    We evaluated the prediction that postural instability would precede the subjective symptoms of motion sickness in a fixed-base flight simulator. Participants sat in a cockpit in a video projection dome and were exposed to optical flow that oscillated in the roll axis with exposure durations typical of flight simulation. The frequencies of oscillation were those that characterize spontaneous postural sway during stance. Head motion was measured prior to and during exposure to imposed optical flow. Of 14 participants, 6 were classified as motion sick, either during or after exposure to the optical oscillation. Prior to the onset of subjective symptoms, head motion among participants who later became sick was significantly greater than among participants who did not become motion sick. We argue that the results support the postural instability theory of motion sickness. Actual or potential applications include the prevention or mitigation of motion sickness in virtual environments.

  2. Development of a high resolution laser based angle-resolving time-of-flight photoelectron spectrometer

    CERN Document Server

    Berntsen, M H; Tjernberg, O

    2011-01-01

    We present the design and performance of a novel Laser-based Angle-Resolving Time-of-Flight (LARTOF) system for photoemission from solids in the vacuum ultraviolet (VUV) energy range. A pulsed laser provides photons which through a third harmonic generation (THG) process performed in a xenon filled gas cell generates VUV photons of energy 10.5 eV. The time-of-flight analyzer is able to collect all electrons that are emitted from the sample within a circular cone of up to +/-15 degrees. By simultaneously measuring the energy and emission angle along two spatial directions for the electrons the analyzer provides three-dimensional detection capability. Data from a test measurement performed on the Au(111) surface state is presented along with some more advanced measurements of the Fermi surface of the high-temperature superconductor Bi2212.

  3. Flame Image Segmentation Based on the Bee Colony Algorithm with Characteristics of Levy Flights

    Directory of Open Access Journals (Sweden)

    Xiaolin Zhang

    2015-01-01

    Full Text Available The real-time processing of the image segmentation method with accuracy is very important in the application of the flame image detection system. This paper considers a novel method for flame image segmentation. It is the bee colony algorithm with characteristics enhancement of Levy flights against the problems of the algorithm during segmentation, including long calculation time and poor stability. By introducing the idea of Levy flights, this method designs a new local search strategy. By setting the current optimal value and based on the collaboration between the populations, it reinforces the overall convergence speed. By adopting the new fitness evaluation method and combining it with the two-dimensional entropy multithreshold segmentation principle, this paper develops a threshold segmentation test of the flame image. Test results show that this method has some advantages in terms of accuracy of threshold selection and calculation time. The robustness of the algorithm meets the actual demands in the engineering application.

  4. Oceanic Flights and Airspace: Improving Efficiency by Trajectory-Based Operations

    Science.gov (United States)

    Fernandes, Alicia Borgman; Rebollo, Juan; Koch, Michael

    2016-01-01

    Oceanic operations suffer from multiple inefficiencies, including pre-departure planning that does not adequately consider uncertainty in the proposed trajectory, restrictions on the routes that a flight operator can choose for an oceanic crossing, time-consuming processes and procedures for amending en route trajectories, and difficulties exchanging data between Flight Information Regions (FIRs). These inefficiencies cause aircraft to fly suboptimal trajectories, burning fuel and time that could be conserved. A concept to support integration of existing and emerging capabilities and concepts is needed to transition to an airspace system that employs Trajectory Based Operations (TBO) to improve efficiency and safety in oceanic operations. This paper describes such a concept and the results of preliminary activities to evaluate the concept, including a stakeholder feedback activity, user needs analysis, and high level benefits analysis.

  5. Flight validation of ground-based assessment for control power requirements at high angles of attack

    Science.gov (United States)

    Ogburn, Marilyn E.; Ross, Holly M.; Foster, John V.; Pahle, Joseph W.; Sternberg, Charles A.; Traven, Ricardo; Lackey, James B.; Abbott, Troy D.

    1994-01-01

    A review is presented in viewgraph format of an ongoing NASA/U.S. Navy study to determine control power requirements at high angles of attack for the next generation high-performance aircraft. This paper focuses on recent flight test activities using the NASA High Alpha Research Vehicle (HARV), which are intended to validate results of previous ground-based simulation studies. The purpose of this study is discussed, and the overall program structure, approach, and objectives are described. Results from two areas of investigation are presented: (1) nose-down control power requirements and (2) lateral-directional control power requirements. Selected results which illustrate issues and challenges that are being addressed in the study are discussed including test methodology, comparisons between simulation and flight, and general lessons learned.

  6. Autonomous Resource Allocation and Task Management for Multi-Spacecraft Formatio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Autonomous multiple spacecraft represent a critical enabling technology for future space missions. Currently, significant pre-flight planning and ground tasking are...

  7. Nonlinear Feedforward Control for Wind Disturbance Rejection on Autonomous Helicopter

    DEFF Research Database (Denmark)

    Bisgaard, Morten; la Cour-Harbo, Anders; A. Danapalasingam, Kumeresan

    2010-01-01

    for the purpose. The model is inverted for the calculation of rotor collective and cyclic pitch angles given the wind disturbance. The control strategy is then applied on a small helicopter in a controlled wind environment and flight tests demonstrates the effectiveness and advantage of the feedforward controller.......This paper presents the design and verification of a model based nonlinear feedforward controller for wind disturbance rejection on autonomous helicopters. The feedforward control is based on a helicopter model that is derived using a number of carefully chosen simplifications to make it suitable...

  8. Robust Huber-Based Iterated Divided Difference Filtering with Application to Cooperative Localization of Autonomous Underwater Vehicles

    Science.gov (United States)

    Gao, Wei; Liu, Yalong; Xu, Bo

    2014-01-01

    A new algorithm called Huber-based iterated divided difference filtering (HIDDF) is derived and applied to cooperative localization of autonomous underwater vehicles (AUVs) supported by a single surface leader. The position states are estimated using acoustic range measurements relative to the leader, in which some disadvantages such as weak observability, large initial error and contaminated measurements with outliers are inherent. By integrating both merits of iterated divided difference filtering (IDDF) and Huber's M-estimation methodology, the new filtering method could not only achieve more accurate estimation and faster convergence contrast to standard divided difference filtering (DDF) in conditions of weak observability and large initial error, but also exhibit robustness with respect to outlier measurements, for which the standard IDDF would exhibit severe degradation in estimation accuracy. The correctness as well as validity of the algorithm is demonstrated through experiment results. PMID:25536004

  9. Teaching and implementing autonomous robotic lab walkthroughs in a biotech laboratory through model-based visual tracking

    Science.gov (United States)

    Wojtczyk, Martin; Panin, Giorgio; Röder, Thorsten; Lenz, Claus; Nair, Suraj; Heidemann, Rüdiger; Goudar, Chetan; Knoll, Alois

    2010-01-01

    After utilizing robots for more than 30 years for classic industrial automation applications, service robots form a constantly increasing market, although the big breakthrough is still awaited. Our approach to service robots was driven by the idea of supporting lab personnel in a biotechnology laboratory. After initial development in Germany, a mobile robot platform extended with an industrial manipulator and the necessary sensors for indoor localization and object manipulation, has been shipped to Bayer HealthCare in Berkeley, CA, USA, a global player in the sector of biopharmaceutical products, located in the San Francisco bay area. The determined goal of the mobile manipulator is to support the off-shift staff to carry out completely autonomous or guided, remote controlled lab walkthroughs, which we implement utilizing a recent development of our computer vision group: OpenTL - an integrated framework for model-based visual tracking.

  10. Implementation of Obstacle-Avoidance Control for an Autonomous Omni-Directional Mobile Robot Based on Extension Theory

    Directory of Open Access Journals (Sweden)

    Yi-Chung Lai

    2012-10-01

    Full Text Available The paper demonstrates a following robot with omni-directional wheels, which is able to take action to avoid obstacles. The robot design is based on both fuzzy and extension theory. Fuzzy theory was applied to tune the PMW signal of the motor revolution, and correct path deviation issues encountered when the robot is moving. Extension theory was used to build a robot obstacle-avoidance model. Various mobile models were developed to handle different types of obstacles. The ultrasonic distance sensors mounted on the robot were used to estimate the distance to obstacles. If an obstacle is encountered, the correlation function is evaluated and the robot avoids the obstacle autonomously using the most appropriate mode. The effectiveness of the proposed approach was verified through several tracking experiments, which demonstrates the feasibility of a fuzzy path tracker as well as the extensible collision avoidance system.

  11. Implementation of obstacle-avoidance control for an autonomous omni-directional mobile robot based on extension theory.

    Science.gov (United States)

    Pai, Neng-Sheng; Hsieh, Hung-Hui; Lai, Yi-Chung

    2012-10-16

    The paper demonstrates a following robot with omni-directional wheels, which is able to take action to avoid obstacles. The robot design is based on both fuzzy and extension theory. Fuzzy theory was applied to tune the PMW signal of the motor revolution, and correct path deviation issues encountered when the robot is moving. Extension theory was used to build a robot obstacle-avoidance model. Various mobile models were developed to handle different types of obstacles. The ultrasonic distance sensors mounted on the robot were used to estimate the distance to obstacles. If an obstacle is encountered, the correlation function is evaluated and the robot avoids the obstacle autonomously using the most appropriate mode. The effectiveness of the proposed approach was verified through several tracking experiments, which demonstrates the feasibility of a fuzzy path tracker as well as the extensible collision avoidance system.

  12. A flight management algorithm and guidance for fuel-conservative descents in a time-based metered air traffic environment: Development and flight test results

    Science.gov (United States)

    Knox, C. E.

    1984-01-01

    A simple airborne flight management descent algorithm designed to define a flight profile subject to the constraints of using idle thrust, a clean airplane configuration (landing gear up, flaps zero, and speed brakes retracted), and fixed-time end conditions was developed and flight tested in the NASA TSRV B-737 research airplane. The research test flights, conducted in the Denver ARTCC automated time-based metering LFM/PD ATC environment, demonstrated that time guidance and control in the cockpit was acceptable to the pilots and ATC controllers and resulted in arrival of the airplane over the metering fix with standard deviations in airspeed error of 6.5 knots, in altitude error of 23.7 m (77.8 ft), and in arrival time accuracy of 12 sec. These accuracies indicated a good representation of airplane performance and wind modeling. Fuel savings will be obtained on a fleet-wide basis through a reduction of the time error dispersions at the metering fix and on a single-airplane basis by presenting the pilot with guidance for a fuel-efficient descent.

  13. Autonomous Formations of Multi-Agent Systems

    Science.gov (United States)

    Dhali, Sanjana; Joshi, Suresh M.

    2013-01-01

    Autonomous formation control of multi-agent dynamic systems has a number of applications that include ground-based and aerial robots and satellite formations. For air vehicles, formation flight ("flocking") has the potential to significantly increase airspace utilization as well as fuel efficiency. This presentation addresses two main problems in multi-agent formations: optimal role assignment to minimize the total cost (e.g., combined distance traveled by all agents); and maintaining formation geometry during flock motion. The Kuhn-Munkres ("Hungarian") algorithm is used for optimal assignment, and consensus-based leader-follower type control architecture is used to maintain formation shape despite the leader s independent movements. The methods are demonstrated by animated simulations.

  14. Hybrid Kalman Filter/Fuzzy Logic based Position Control of Autonomous Mobile Robot

    Directory of Open Access Journals (Sweden)

    Nitin Afzulpurkar

    2008-11-01

    Full Text Available This paper describes position control of autonomous mobile robot using combination of Kalman filter and Fuzzy logic techniques. Both techniques have been used to fuse information from internal and external sensors to navigate a typical mobile robot in an unknown environment. An obstacle avoidance algorithm utilizing stereo vision technique has been implemented for obstacle detection. The odometry errors due to systematic-errors (such as unequal wheel diameter, the effect of the encoder resolution etc. and/or non-systematic errors (ground plane, wheel-slip etc. contribute to various motion control problems of the robot. During the robot moves, whether straight-line and/or arc, create the position and orientation errors which depend on systematic and/or non-systematic odometry errors. The main concern in most of the navigating systems is to achieve the real-time and robustness performances to precisely control the robot movements. The objective of this research is to improve the position and the orientation of robot motion. From the simulation and experiments, we prove that the proposed mobile robot moves from start position to goal position with greater accuracy avoiding obstacles.

  15. WEB-BASED JOURNALS IN THE CLASSROOM: MOTIVATION AND AUTONOMOUS LEARNING

    Directory of Open Access Journals (Sweden)

    Andrew Pollard

    2015-01-01

    Full Text Available Abstract: The use of Web 2.0 in the language classroom is an area of exploration and interest to many. In recent years, much research has looked at the use of blogs in the assistance of language development, and this paper continues in a similar fashion. One key area where this paper adds to the field however, is that it looks at a Web 2.0 portal specifically aimed at language learners; the portal in question is Lang-8, which in conjunction with being similar to a blogging platform, also provides similar functions to a social networking service. This research exposed 12 Korean participants to Lang-8 as part of a credit-bearing university writing course. The participants made weekly journal entries on Lang-8, and upon completion of the course, were given an anonymous online survey to complete. The survey addressed areas relating to online language journals, corrective feedback, motivation, and learner autonomy. Overall, the participants reported that the use of Lang-8 positively affected their motivation levels, had positive experiences through received varied corrective feedback, and were exposed to a portal that allowed for more autonomous learning.

  16. Geomagnetic Navigation of Autonomous Underwater Vehicle Based on Multi-objective Evolutionary Algorithm

    Directory of Open Access Journals (Sweden)

    Hong Li

    2017-07-01

    Full Text Available This paper presents a multi-objective evolutionary algorithm of bio-inspired geomagnetic navigation for Autonomous Underwater Vehicle (AUV. Inspired by the biological navigation behavior, the solution was proposed without using a priori information, simply by magnetotaxis searching. However, the existence of the geomagnetic anomalies has significant influence on the geomagnetic navigation system, which often disrupts the distribution of the geomagnetic field. An extreme value region may easily appear in abnormal regions, which makes AUV lost in the navigation phase. This paper proposes an improved bio-inspired algorithm with behavior constraints, for sake of making AUV escape from the abnormal region. First, the navigation problem is considered as the optimization problem. Second, the environmental monitoring operator is introduced, to determine whether the algorithm falls into the geomagnetic anomaly region. Then, the behavior constraint operator is employed to get out of the abnormal region. Finally, the termination condition is triggered. Compared to the state-of- the-art, the proposed approach effectively overcomes the disturbance of the geomagnetic abnormal. The simulation result demonstrates the reliability and feasibility of the proposed approach in complex environments.

  17. Cost-Effective Encryption-Based Autonomous Routing Protocol for Efficient and Secure Wireless Sensor Networks

    Science.gov (United States)

    Saleem, Kashif; Derhab, Abdelouahid; Orgun, Mehmet A.; Al-Muhtadi, Jalal; Rodrigues, Joel J. P. C.; Khalil, Mohammed Sayim; Ali Ahmed, Adel

    2016-01-01

    The deployment of intelligent remote surveillance systems depends on wireless sensor networks (WSNs) composed of various miniature resource-constrained wireless sensor nodes. The development of routing protocols for WSNs is a major challenge because of their severe resource constraints, ad hoc topology and dynamic nature. Among those proposed routing protocols, the biology-inspired self-organized secure autonomous routing protocol (BIOSARP) involves an artificial immune system (AIS) that requires a certain amount of time to build up knowledge of neighboring nodes. The AIS algorithm uses this knowledge to distinguish between self and non-self neighboring nodes. The knowledge-building phase is a critical period in the WSN lifespan and requires active security measures. This paper proposes an enhanced BIOSARP (E-BIOSARP) that incorporates a random key encryption mechanism in a cost-effective manner to provide active security measures in WSNs. A detailed description of E-BIOSARP is presented, followed by an extensive security and performance analysis to demonstrate its efficiency. A scenario with E-BIOSARP is implemented in network simulator 2 (ns-2) and is populated with malicious nodes for analysis. Furthermore, E-BIOSARP is compared with state-of-the-art secure routing protocols in terms of processing time, delivery ratio, energy consumption, and packet overhead. The findings show that the proposed mechanism can efficiently protect WSNs from selective forwarding, brute-force or exhaustive key search, spoofing, eavesdropping, replaying or altering of routing information, cloning, acknowledgment spoofing, HELLO flood attacks, and Sybil attacks. PMID:27043572

  18. Cost-Effective Encryption-Based Autonomous Routing Protocol for Efficient and Secure Wireless Sensor Networks.

    Science.gov (United States)

    Saleem, Kashif; Derhab, Abdelouahid; Orgun, Mehmet A; Al-Muhtadi, Jalal; Rodrigues, Joel J P C; Khalil, Mohammed Sayim; Ali Ahmed, Adel

    2016-03-31

    The deployment of intelligent remote surveillance systems depends on wireless sensor networks (WSNs) composed of various miniature resource-constrained wireless sensor nodes. The development of routing protocols for WSNs is a major challenge because of their severe resource constraints, ad hoc topology and dynamic nature. Among those proposed routing protocols, the biology-inspired self-organized secure autonomous routing protocol (BIOSARP) involves an artificial immune system (AIS) that requires a certain amount of time to build up knowledge of neighboring nodes. The AIS algorithm uses this knowledge to distinguish between self and non-self neighboring nodes. The knowledge-building phase is a critical period in the WSN lifespan and requires active security measures. This paper proposes an enhanced BIOSARP (E-BIOSARP) that incorporates a random key encryption mechanism in a cost-effective manner to provide active security measures in WSNs. A detailed description of E-BIOSARP is presented, followed by an extensive security and performance analysis to demonstrate its efficiency. A scenario with E-BIOSARP is implemented in network simulator 2 (ns-2) and is populated with malicious nodes for analysis. Furthermore, E-BIOSARP is compared with state-of-the-art secure routing protocols in terms of processing time, delivery ratio, energy consumption, and packet overhead. The findings show that the proposed mechanism can efficiently protect WSNs from selective forwarding, brute-force or exhaustive key search, spoofing, eavesdropping, replaying or altering of routing information, cloning, acknowledgment spoofing, HELLO flood attacks, and Sybil attacks.

  19. Balloon flight test of a Compton telescope based on scintillators with silicon photomultiplier readouts

    Energy Technology Data Exchange (ETDEWEB)

    Bloser, P.F., E-mail: Peter.Bloser@unh.edu; Legere, J.S.; Bancroft, C.M.; Ryan, J.M.; McConnell, M.L.

    2016-03-11

    We present the results of the first high-altitude balloon flight test of a concept for an advanced Compton telescope making use of modern scintillator materials with silicon photomultiplier (SiPM) readouts. There is a need in the fields of high-energy astronomy and solar physics for new medium-energy gamma-ray (~0.4–10 MeV) detectors capable of making sensitive observations of both line and continuum sources over a wide dynamic range. A fast scintillator-based Compton telescope with SiPM readouts is a promising solution to this instrumentation challenge, since the fast response of the scintillators permits both the rejection of background via time-of-flight (ToF) discrimination and the ability to operate at high count rates. The Solar Compton Telescope (SolCompT) prototype presented here was designed to demonstrate stable performance of this technology under balloon-flight conditions. The SolCompT instrument was a simple two-element Compton telescope, consisting of an approximately one-inch cylindrical stilbene crystal for a scattering detector and a one-inch cubic LaBr{sub 3}:Ce crystal for a calorimeter detector. Both scintillator detectors were read out by 2×2 arrays of Hamamatsu S11828-3344 MPPC devices. Custom front-end electronics provided optimum signal rise time and linearity, and custom power supplies automatically adjusted the SiPM bias voltage to compensate for temperature-induced gain variations. A tagged calibration source, consisting of ~240 nCi of {sup 60}Co embedded in plastic scintillator, was placed in the field of view and provided a known source of gamma rays to measure in flight. The SolCompT balloon payload was launched on 24 August 2014 from Fort Sumner, NM, and spent ~3.75 h at a float altitude of ~123,000 ft. The instrument performed well throughout the flight. After correcting for small (~10%) residual gain variations, we measured an in-flight ToF resolution of ~760 ps (FWHM). Advanced scintillators with SiPM readouts continue to show

  20. Zero phase error control based on neural compensation for flight simulator servo system

    Institute of Scientific and Technical Information of China (English)

    Liu Jinkun; He Peng; Er Lianjie

    2006-01-01

    Using the future desired input value, zero phase error controller enables the overall system's frequency response exhibit zero phase shift for all frequencies and a small gain error at low frequency range, and based on this, a new algorithm is presented to design the feedforward controller. However, zero phase error controller is only suitable for certain linear system. To reduce the tracking error and improve robustness, the design of the proposed feedforward controller uses a neural compensation based on diagonal recurrent neural network. Simulation and real-time control results for flight simulator servo system show the effectiveness of the proposed approach.

  1. Autonomous Airship

    Directory of Open Access Journals (Sweden)

    Martin POSPÍŠILÍK

    2009-06-01

    Full Text Available This paper describes a project of attaching the autonomous monitoring system to a small helium airship. The airship is capable of independent operating inside a closed hall, being driven by means of ultrasonic detectors. It is accommodated to carry different monitoring units providing students with the opportunity to process various experiments and measurements. In the first experiment, the airship will carry WiFi router, camera and IP Relay by means of which the pertinent control of the airship through external web interface is enabled, independently on the ultrasonic detecting system.

  2. Autonomous Search

    CERN Document Server

    Hamadi, Youssef; Saubion, Frédéric

    2012-01-01

    Decades of innovations in combinatorial problem solving have produced better and more complex algorithms. These new methods are better since they can solve larger problems and address new application domains. They are also more complex which means that they are hard to reproduce and often harder to fine-tune to the peculiarities of a given problem. This last point has created a paradox where efficient tools are out of reach of practitioners. Autonomous search (AS) represents a new research field defined to precisely address the above challenge. Its major strength and originality consist in the

  3. Balloon Flight Test of a Compton Telescope Based on Scintillators with Silicon Photomultiplier Readouts

    CERN Document Server

    Bloser, P F; Bancroft, C M; Ryan, J M; McConnell, M L

    2016-01-01

    We present the results of the first high-altitude balloon flight test of a concept for an advanced Compton telescope making use of modern scintillator materials with silicon photomultiplier (SiPM) readouts. There is a need in the fields of high-energy astronomy and solar physics for new medium-energy gamma-ray (~0.4 - 10 MeV) detectors capable of making sensitive observations. A fast scintillator- based Compton telescope with SiPM readouts is a promising solution to this instrumentation challenge, since the fast response of the scintillators permits the rejection of background via time-of-flight (ToF) discrimination. The Solar Compton Telescope (SolCompT) prototype was designed to demonstrate stable performance of this technology under balloon-flight conditions. The SolCompT instrument was a simple two-element Compton telescope, consisting of an approximately one-inch cylindrical stilbene crystal for a scattering detector and a one-inch cubic LaBr3:Ce crystal for a calorimeter detector. Both scintillator dete...

  4. A strategic flight conflict avoidance approach based on a memetic algorithm

    Institute of Scientific and Technical Information of China (English)

    Guan Xiangmin; Zhang Xuejun; Han Dong; Zhu Yanbo; Lv Ji; Su Jing

    2014-01-01

    Conflict avoidance (CA) plays a crucial role in guaranteeing the airspace safety. The cur-rent approaches, mostly focusing on a short-term situation which eliminates conflicts via local adjust-ment, cannot provide a global solution. Recently, long-term conflict avoidance approaches, which are proposed to provide solutions via strategically planning traffic flow from a global view, have attracted more attentions. With consideration of the situation in China, there are thousands of flights per day and the air route network is large and complex, which makes the long-term problem to be a large-scale combinatorial optimization problem with complex constraints. To minimize the risk of premature convergence being faced by current approaches and obtain higher quality solutions, in this work, we present an effective strategic framework based on a memetic algorithm (MA), which can markedly improve search capability via a combination of population-based global search and local improve-ments made by individuals. In addition, a specially designed local search operator and an adaptive local search frequency strategy are proposed to improve the solution quality. Furthermore, a fast genetic algorithm (GA) is presented as the global optimization method. Empirical studies using real traffic data of the Chinese air route network and daily flight plans show that our approach outper-formed the existing approaches including the GA based approach and the cooperative coevolution based approach as well as some well-known memetic algorithm based approaches.

  5. Stereo Vision Based Terrain Mapping for Off-Road Autonomous Navigation

    Science.gov (United States)

    Rankin, Arturo L.; Huertas, Andres; Matthies, Larry H.

    2009-01-01

    Successful off-road autonomous navigation by an unmanned ground vehicle (UGV) requires reliable perception and representation of natural terrain. While perception algorithms are used to detect driving hazards, terrain mapping algorithms are used to represent the detected hazards in a world model a UGV can use to plan safe paths. There are two primary ways to detect driving hazards with perception sensors mounted to a UGV: binary obstacle detection and traversability cost analysis. Binary obstacle detectors label terrain as either traversable or non-traversable, whereas, traversability cost analysis assigns a cost to driving over a discrete patch of terrain. In uncluttered environments where the non-obstacle terrain is equally traversable, binary obstacle detection is sufficient. However, in cluttered environments, some form of traversability cost analysis is necessary. The Jet Propulsion Laboratory (JPL) has explored both approaches using stereo vision systems. A set of binary detectors has been implemented that detect positive obstacles, negative obstacles, tree trunks, tree lines, excessive slope, low overhangs, and water bodies. A compact terrain map is built from each frame of stereo images. The mapping algorithm labels cells that contain obstacles as no-go regions, and encodes terrain elevation, terrain classification, terrain roughness, traversability cost, and a confidence value. The single frame maps are merged into a world map where temporal filtering is applied. In previous papers, we have described our perception algorithms that perform binary obstacle detection. In this paper, we summarize the terrain mapping capabilities that JPL has implemented during several UGV programs over the last decade and discuss some challenges to building terrain maps with stereo range data.

  6. Stereo Vision Based Terrain Mapping for Off-Road Autonomous Navigation

    Science.gov (United States)

    Rankin, Arturo L.; Huertas, Andres; Matthies, Larry H.

    2009-01-01

    Successful off-road autonomous navigation by an unmanned ground vehicle (UGV) requires reliable perception and representation of natural terrain. While perception algorithms are used to detect driving hazards, terrain mapping algorithms are used to represent the detected hazards in a world model a UGV can use to plan safe paths. There are two primary ways to detect driving hazards with perception sensors mounted to a UGV: binary obstacle detection and traversability cost analysis. Binary obstacle detectors label terrain as either traversable or non-traversable, whereas, traversability cost analysis assigns a cost to driving over a discrete patch of terrain. In uncluttered environments where the non-obstacle terrain is equally traversable, binary obstacle detection is sufficient. However, in cluttered environments, some form of traversability cost analysis is necessary. The Jet Propulsion Laboratory (JPL) has explored both approaches using stereo vision systems. A set of binary detectors has been implemented that detect positive obstacles, negative obstacles, tree trunks, tree lines, excessive slope, low overhangs, and water bodies. A compact terrain map is built from each frame of stereo images. The mapping algorithm labels cells that contain obstacles as no-go regions, and encodes terrain elevation, terrain classification, terrain roughness, traversability cost, and a confidence value. The single frame maps are merged into a world map where temporal filtering is applied. In previous papers, we have described our perception algorithms that perform binary obstacle detection. In this paper, we summarize the terrain mapping capabilities that JPL has implemented during several UGV programs over the last decade and discuss some challenges to building terrain maps with stereo range data.

  7. Cost-Effective Encryption-Based Autonomous Routing Protocol for Efficient and Secure Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Kashif Saleem

    2016-03-01

    Full Text Available The deployment of intelligent remote surveillance systems depends on wireless sensor networks (WSNs composed of various miniature resource-constrained wireless sensor nodes. The development of routing protocols for WSNs is a major challenge because of their severe resource constraints, ad hoc topology and dynamic nature. Among those proposed routing protocols, the biology-inspired self-organized secure autonomous routing protocol (BIOSARP involves an artificial immune system (AIS that requires a certain amount of time to build up knowledge of neighboring nodes. The AIS algorithm uses this knowledge to distinguish between self and non-self neighboring nodes. The knowledge-building phase is a critical period in the WSN lifespan and requires active security measures. This paper proposes an enhanced BIOSARP (E-BIOSARP that incorporates a random key encryption mechanism in a cost-effective manner to provide active security measures in WSNs. A detailed description of E-BIOSARP is presented, followed by an extensive security and performance analysis to demonstrate its efficiency. A scenario with E-BIOSARP is implemented in network simulator 2 (ns-2 and is populated with malicious nodes for analysis. Furthermore, E-BIOSARP is compared with state-of-the-art secure routing protocols in terms of processing time, delivery ratio, energy consumption, and packet overhead. The findings show that the proposed mechanism can efficiently protect WSNs from selective forwarding, brute-force or exhaustive key search, spoofing, eavesdropping, replaying or altering of routing information, cloning, acknowledgment spoofing, HELLO flood attacks, and Sybil attacks.

  8. Autonomous Undersea Observations

    Science.gov (United States)

    2016-06-13

    less expensive sensor systems for a variety of applications, including measurement of physical characteristics of the ocean, threat detection, and...multiple autonomous environmental sensors within an acoustic modem-based infrastructure capable of communicating to and from the sensors and to and...networks, and telesonar with high speed platforms. This effort is concentrating on the development and demonstration of the two modem- based sensors . We

  9. Monte Carlo Registration and Its Application with Autonomous Robots

    Directory of Open Access Journals (Sweden)

    Christian Rink

    2016-01-01

    Full Text Available This work focuses on Monte Carlo registration methods and their application with autonomous robots. A streaming and an offline variant are developed, both based on a particle filter. The streaming registration is performed in real-time during data acquisition with a laser striper allowing for on-the-fly pose estimation. Thus, the acquired data can be instantly utilized, for example, for object modeling or robot manipulation, and the laser scan can be aborted after convergence. Curvature features are calculated online and the estimated poses are optimized in the particle weighting step. For sampling the pose particles, uniform, normal, and Bingham distributions are compared. The methods are evaluated with a high-precision laser striper attached to an industrial robot and with a noisy Time-of-Flight camera attached to service robots. The shown applications range from robot assisted teleoperation, over autonomous object modeling, to mobile robot localization.

  10. Hybrid Motion Planning Method for Autonomous Robots Using Kinect Based Sensor Fusion and Virtual Plane Approach in Dynamic Environments

    Directory of Open Access Journals (Sweden)

    Doopalam Tuvshinjargal

    2015-01-01

    Full Text Available A new reactive motion planning method for an autonomous vehicle in dynamic environments is proposed. The new dynamic motion planning method combines a virtual plane based reactive motion planning technique with a sensor fusion based obstacle detection approach, which results in improving robustness and autonomy of vehicle navigation within unpredictable dynamic environments. The key feature of the new reactive motion planning method is based on a local observer in the virtual plane which allows the effective transformation of complex dynamic planning problems into simple stationary in the virtual plane. In addition, a sensor fusion based obstacle detection technique provides the pose estimation of moving obstacles by using a Kinect sensor and a sonar sensor, which helps to improve the accuracy and robustness of the reactive motion planning approach in uncertain dynamic environments. The performance of the proposed method was demonstrated through not only simulation studies but also field experiments using multiple moving obstacles even in hostile environments where conventional method failed.

  11. Development of autonomous multirotor platform for exploration missions

    Science.gov (United States)

    Czyba, Roman; Janik, Marcin; Kurgan, Oliver; Niezabitowski, Michał; Nocoń, Marek

    2016-06-01

    This paper outlines development process of unmanned multirotor aerial vehicle HF-4X, which consists of design and manufacturing semi-autonomous UAV dedicated for indoor flight, which would be capable of stable and controllable mission flight. A micro air vehicle was designed to participate in the International Micro Air Vehicle Conference and Flight Competition. In this paper much attention was paid to the structure of flight control system, stabilization algorithms, analysis of IMU sensors, fusion algorithms.

  12. Development of autonomous multirotor platform for exploration missions

    Energy Technology Data Exchange (ETDEWEB)

    Czyba, Roman; Janik, Marcin; Kurgan, Oliver; Niezabitowski, Michał; Nocoń, Marek

    2016-06-08

    This paper outlines development process of unmanned multirotor aerial vehicle HF-4X, which consists of design and manufacturing semi-autonomous UAV dedicated for indoor flight, which would be capable of stable and controllable mission flight. A micro air vehicle was designed to participate in the International Micro Air Vehicle Conference and Flight Competition. In this paper much attention was paid to the structure of flight control system, stabilization algorithms, analysis of IMU sensors, fusion algorithms.

  13. Design factors and considerations for a time-based flight management system

    Science.gov (United States)

    Vicroy, D. D.; Williams, D. H.; Sorensen, J. A.

    1986-01-01

    Recent NASA Langley Research Center research to develop a technology data base from which an advanced Flight Management System (FMS) design might evolve is reviewed. In particular, the generation of fixed range cruise/descent reference trajectories which meet predefined end conditions of altitude, speed, and time is addressed. Results on the design and theoretical basis of the trajectory generation algorithm are presented, followed by a brief discussion of a series of studies that are being conducted to determine the accuracy requirements of the aircraft and weather models resident in the trajectory generation algorithm. Finally, studies to investigate the interface requirements between the pilot and an advanced FMS are considered.

  14. Orion Flight Test 1 Architecture: Observed Benefits of a Model Based Engineering Approach

    Science.gov (United States)

    Simpson, Kimberly A.; Sindiy, Oleg V.; McVittie, Thomas I.

    2012-01-01

    This paper details how a NASA-led team is using a model-based systems engineering approach to capture, analyze and communicate the end-to-end information system architecture supporting the first unmanned orbital flight of the Orion Multi-Purpose Crew Exploration Vehicle. Along with a brief overview of the approach and its products, the paper focuses on the observed program-level benefits, challenges, and lessons learned; all of which may be applied to improve system engineering tasks for characteristically similarly challenges

  15. A 3D scanning device for architectural survey based on time-of-flight technology

    Science.gov (United States)

    Fontana, Raffaella; Gambino, Maria Chiara; Gianfrate, Gabriella; Greco, Marinella; Pampaloni, Enrico; Pezzati, Luca

    2004-09-01

    This work is intended to show the results of a few architectural and archaeological surveys realized by means of a 3D scanning device, based on TOF (Time-Of-Flight) technology. The instrument was set up by the Art Diagnostic Group of the National Institute for Applied Optics (INOA) and it is composed by a high precision scanning system equipped with a commercial low-cost distance-meter. This device was projected in order to provide the following characteristics: reliability, good accuracy and compatibility with other systems and it is devoted to applications in Cultural Heritage field.

  16. Chaotic Teaching-Learning-Based Optimization with Lévy Flight for Global Numerical Optimization

    Directory of Open Access Journals (Sweden)

    Xiangzhu He

    2016-01-01

    Full Text Available Recently, teaching-learning-based optimization (TLBO, as one of the emerging nature-inspired heuristic algorithms, has attracted increasing attention. In order to enhance its convergence rate and prevent it from getting stuck in local optima, a novel metaheuristic has been developed in this paper, where particular characteristics of the chaos mechanism and Lévy flight are introduced to the basic framework of TLBO. The new algorithm is tested on several large-scale nonlinear benchmark functions with different characteristics and compared with other methods. Experimental results show that the proposed algorithm outperforms other algorithms and achieves a satisfactory improvement over TLBO.

  17. Chaotic Teaching-Learning-Based Optimization with Lévy Flight for Global Numerical Optimization.

    Science.gov (United States)

    He, Xiangzhu; Huang, Jida; Rao, Yunqing; Gao, Liang

    2016-01-01

    Recently, teaching-learning-based optimization (TLBO), as one of the emerging nature-inspired heuristic algorithms, has attracted increasing attention. In order to enhance its convergence rate and prevent it from getting stuck in local optima, a novel metaheuristic has been developed in this paper, where particular characteristics of the chaos mechanism and Lévy flight are introduced to the basic framework of TLBO. The new algorithm is tested on several large-scale nonlinear benchmark functions with different characteristics and compared with other methods. Experimental results show that the proposed algorithm outperforms other algorithms and achieves a satisfactory improvement over TLBO.

  18. Creating a Realistic Weather Environment for Motion-Based Piloted Flight Simulation

    Science.gov (United States)

    Daniels, Taumi S.; Schaffner, Philip R.; Evans, Emory T.; Neece, Robert T.; Young, Steve D.

    2012-01-01

    A flight simulation environment is being enhanced to facilitate experiments that evaluate research prototypes of advanced onboard weather radar, hazard/integrity monitoring (HIM), and integrated alerting and notification (IAN) concepts in adverse weather conditions. The simulation environment uses weather data based on real weather events to support operational scenarios in a terminal area. A simulated atmospheric environment was realized by using numerical weather data sets. These were produced from the High-Resolution Rapid Refresh (HRRR) model hosted and run by the National Oceanic and Atmospheric Administration (NOAA). To align with the planned flight simulation experiment requirements, several HRRR data sets were acquired courtesy of NOAA. These data sets coincided with severe weather events at the Memphis International Airport (MEM) in Memphis, TN. In addition, representative flight tracks for approaches and departures at MEM were generated and used to develop and test simulations of (1) what onboard sensors such as the weather radar would observe; (2) what datalinks of weather information would provide; and (3) what atmospheric conditions the aircraft would experience (e.g. turbulence, winds, and icing). The simulation includes a weather radar display that provides weather and turbulence modes, derived from the modeled weather along the flight track. The radar capabilities and the pilots controls simulate current-generation commercial weather radar systems. Appropriate data-linked weather advisories (e.g., SIGMET) were derived from the HRRR weather models and provided to the pilot consistent with NextGen concepts of use for Aeronautical Information Service (AIS) and Meteorological (MET) data link products. The net result of this simulation development was the creation of an environment that supports investigations of new flight deck information systems, methods for incorporation of better weather information, and pilot interface and operational improvements

  19. Diabetic autonomic neuropathy.

    Science.gov (United States)

    Freeman, Roy

    2014-01-01

    Diabetes mellitus is the commonest cause of an autonomic neuropathy in the developed world. Diabetic autonomic neuropathy causes a constellation of symptoms and signs affecting cardiovascular, urogenital, gastrointestinal, pupillomotor, thermoregulatory, and sudomotor systems. Several discrete syndromes associated with diabetes cause autonomic dysfunction. The most prevalent of these are: generalized diabetic autonomic neuropathy, autonomic neuropathy associated with the prediabetic state, treatment-induced painful and autonomic neuropathy, and transient hypoglycemia-associated autonomic neuropathy. These autonomic manifestations of diabetes are responsible for the most troublesome and disabling features of diabetic peripheral neuropathy and result in a significant proportion of the mortality and morbidity associated with the disease.

  20. An autonomous receiver/digital signal processor applied to ground-based and rocket-borne wave experiments

    Science.gov (United States)

    Dombrowski, M. P.; LaBelle, J.; McGaw, D. G.; Broughton, M. C.

    2016-07-01

    The programmable combined receiver/digital signal processor platform presented in this article is designed for digital downsampling and processing of general waveform inputs with a 66 MHz initial sampling rate and multi-input synchronized sampling. Systems based on this platform are capable of fully autonomous low-power operation, can be programmed to preprocess and filter the data for preselection and reduction, and may output to a diverse array of transmission or telemetry media. We describe three versions of this system, one for deployment on sounding rockets and two for ground-based applications. The rocket system was flown on the Correlation of High-Frequency and Auroral Roar Measurements (CHARM)-II mission launched from Poker Flat Research Range, Alaska, in 2010. It measured auroral "roar" signals at 2.60 MHz. The ground-based systems have been deployed at Sondrestrom, Greenland, and South Pole Station, Antarctica. The Greenland system synchronously samples signals from three spaced antennas providing direction finding of 0-5 MHz waves. It has successfully measured auroral signals and man-made broadcast signals. The South Pole system synchronously samples signals from two crossed antennas, providing polarization information. It has successfully measured the polarization of auroral kilometric radiation-like signals as well as auroral hiss. Further systems are in development for future rocket missions and for installation in Antarctic Automatic Geophysical Observatories.

  1. Chemical Kinetics of the TPS and Base Bleeding During Flight Test

    Science.gov (United States)

    Osipov, Viatcheslav; Ponizhovskaya, Ekaterina; Hafiychuck, Halyna; Luchinsky, Dmitry; Smelyanskiy, Vadim; Dagostino, Mark; Canabal, Francisco; Mobley, Brandon L.

    2012-01-01

    The present research deals with thermal degradation of polyurethane foam (PUF) during flight test. Model of thermal decomposition was developed that accounts for polyurethane kinetics parameters extracted from thermogravimetric analyses and radial heat losses to the surrounding environment. The model predicts mass loss of foam, the temperature and kinetic of release of the exhaust gases and char as function of heat and radiation loads. When PUF is heated, urethane bond break into polyol and isocyanate. In the first stage, isocyanate pyrolyses and oxidizes. As a result, the thermo-char and oil droplets (yellow smoke) are released. In the second decomposition stage, pyrolysis and oxidization of liquid polyol occur. Next, the kinetics of chemical compound release and the information about the reactions occurring in the base area are coupled to the CFD simulations of the base flow in a single first stage motor vertically stacked vehicle configuration. The CFD simulations are performed to estimate the contribution of the hot out-gassing, chemical reactions, and char oxidation to the temperature rise of the base flow. The results of simulations are compared with the flight test data.

  2. A Usability and Learnability Case Study of Glass Flight Deck Interfaces and Pilot Interactions through Scenario-based Training

    Science.gov (United States)

    De Cino, Thomas J., II

    In the aviation industry, digitally produced and presented flight, navigation, and aircraft information is commonly referred to as glass flight decks. Glass flight decks are driven by computer-based subsystems and have long been a part of military and commercial aviation sectors. Over the past 15 years, the General Aviation (GA) sector of the aviation industry has become a recent beneficiary of the rapid advancement of computer-based glass flight deck (GFD) systems. While providing the GA pilot considerable enhancements in the quality of information about the status and operations of the aircraft, training pilots on the use of glass flight decks is often delivered with traditional methods (e.g. textbooks, PowerPoint presentations, user manuals, and limited computer-based training modules). These training methods have been reported as less than desirable in learning to use the glass flight deck interface. Difficulties in achieving a complete understanding of functional and operational characteristics of the GFD systems, acquiring a full understanding of the interrelationships of the varied subsystems, and handling the wealth of flight information provided have been reported. Documented pilot concerns of poor user experience and satisfaction, and problems with the learning the complex and sophisticated interface of the GFD are additional issues with current pilot training approaches. A case study was executed to explore ways to improve training using GFD systems at a Midwestern aviation university. The researcher investigated if variations in instructional systems design and training methods for learning glass flight deck technology would affect the perceptions and attitudes of pilots of the learnability (an attribute of usability) of the glass flight deck interface. Specifically, this study investigated the effectiveness of scenario-based training (SBT) methods to potentially improve pilot knowledge and understanding of a GFD system, and overall pilot user

  3. 2001 Flight Mechanics Symposium

    Science.gov (United States)

    Lynch, John P. (Editor)

    2001-01-01

    This conference publication includes papers and abstracts presented at the Flight Mechanics Symposium held on June 19-21, 2001. Sponsored by the Guidance, Navigation and Control Center of Goddard Space Flight Center, this symposium featured technical papers on a wide range of issues related to attitude/orbit determination, prediction and control; attitude simulation; attitude sensor calibration; theoretical foundation of attitude computation; dynamics model improvements; autonomous navigation; constellation design and formation flying; estimation theory and computational techniques; Earth environment mission analysis and design; and, spacecraft re-entry mission design and operations.

  4. An Adaptive Altitude Information Fusion Method for Autonomous Landing Processes of Small Unmanned Aerial Rotorcraft

    Directory of Open Access Journals (Sweden)

    Xusheng Lei

    2012-09-01

    Full Text Available This paper presents an adaptive information fusion method to improve the accuracy and reliability of the altitude measurement information for small unmanned aerial rotorcraft during the landing process. Focusing on the low measurement performance of sensors mounted on small unmanned aerial rotorcraft, a wavelet filter is applied as a pre-filter to attenuate the high frequency noises in the sensor output. Furthermore, to improve altitude information, an adaptive extended Kalman filter based on a maximum a posteriori criterion is proposed to estimate measurement noise covariance matrix in real time. Finally, the effectiveness of the proposed method is proved by static tests, hovering flight and autonomous landing flight tests.

  5. Embedded Relative Navigation Sensor Fusion Algorithms for Autonomous Rendezvous and Docking Missions

    Science.gov (United States)

    DeKock, Brandon K.; Betts, Kevin M.; McDuffie, James H.; Dreas, Christine B.

    2008-01-01

    bd Systems (a subsidiary of SAIC) has developed a suite of embedded relative navigation sensor fusion algorithms to enable NASA autonomous rendezvous and docking (AR&D) missions. Translational and rotational Extended Kalman Filters (EKFs) were developed for integrating measurements based on the vehicles' orbital mechanics and high-fidelity sensor error models and provide a solution with increased accuracy and robustness relative to any single relative navigation sensor. The filters were tested tinough stand-alone covariance analysis, closed-loop testing with a high-fidelity multi-body orbital simulation, and hardware-in-the-loop (HWIL) testing in the Marshall Space Flight Center (MSFC) Flight Robotics Laboratory (FRL).

  6. A study on model fidelity for model predictive control-based obstacle avoidance in high-speed autonomous ground vehicles

    Science.gov (United States)

    Liu, Jiechao; Jayakumar, Paramsothy; Stein, Jeffrey L.; Ersal, Tulga

    2016-11-01

    This paper investigates the level of model fidelity needed in order for a model predictive control (MPC)-based obstacle avoidance algorithm to be able to safely and quickly avoid obstacles even when the vehicle is close to its dynamic limits. The context of this work is large autonomous ground vehicles that manoeuvre at high speed within unknown, unstructured, flat environments and have significant vehicle dynamics-related constraints. Five different representations of vehicle dynamics models are considered: four variations of the two degrees-of-freedom (DoF) representation as lower fidelity models and a fourteen DoF representation with combined-slip Magic Formula tyre model as a higher fidelity model. It is concluded that the two DoF representation that accounts for tyre nonlinearities and longitudinal load transfer is necessary for the MPC-based obstacle avoidance algorithm in order to operate the vehicle at its limits within an environment that includes large obstacles. For less challenging environments, however, the two DoF representation with linear tyre model and constant axle loads is sufficient.

  7. Development of an autonomic portable single-board computer based high resolution NIRS device for microcirculation analysis.

    Science.gov (United States)

    Rajkumar, E R; Safaie, J; Gupta, R; Pattnaik, D; Abrishamimoghaddam, H; Grebe, R; Wallois, F

    2012-01-01

    Near Infrared Spectroscopy (NIRS) is a wellestablished non-invasive technique for measuring metabolic changes in biological tissue. In this paper we describe the design and development of an autonomic portable single board computer based high resolution NIRS device, which allows quantification of these changes. The sensor-patch consisting of 8LEDs and 2photo-detectorsprovides8 channels for each detector, offering increased depth resolution for monitoring microcirculatory activity..NIRS data is acquired with a sampling rate of about 2Hz per channel using the data acquisition board which consists of a 16 bit ADC, a LED driver and programmable gain amplifiers. The components on the data acquisition board are controlled via the Advantech's PCM-3355L SBC based on Windows XP platform. The software was created using Visual Basic 6.0 and Microsoft Visual C++ 6.0. It offers optionally a real time 'monitoring' and a static data (offline) visualization mode. The most unique feature of the system is its ability to auto-calibrate itself i.e. Adopt the intensity of the LEDs output light to different experimental conditions, e.g. local melanin content, density of the tissue, and emitter-detector distances. To validate the device various experiments have been carried out such as measurements on resting and working gastrocnemius and biceps muscle in ambulatory situations. The achieved results confirmed adequate performance and reliability of the device.

  8. Neutron Radiography Based Visualization and Profiling of Water Uptake in (Un)cracked and Autonomously Healed Cementitious Materials.

    Science.gov (United States)

    Van den Heede, Philip; Van Belleghem, Bjorn; Alderete, Natalia; Van Tittelboom, Kim; De Belie, Nele

    2016-04-26

    Given their low tensile strength, cement-based materials are very susceptible to cracking. These cracks serve as preferential pathways for corrosion inducing substances. For large concrete infrastructure works, currently available time-consuming manual repair techniques are not always an option. Often, one simply cannot reach the damaged areas and when making those areas accessible anyway (e.g., by redirecting traffic), the economic impacts involved would be enormous. Under those circumstances, it might be useful to have concrete with an embedded autonomous healing mechanism. In this paper, the effectiveness of incorporating encapsulated high and low viscosity polyurethane-based healing agents to ensure (multiple) crack healing has been investigated by means of capillary absorption tests on mortar while monitoring the time-dependent water ingress with neutron radiography. Overall visual interpretation and water front/sample cross-section area ratios as well as water profiles representing the area around the crack and their integrals do not show a preference for the high or low viscosity healing agent. Another observation is that in presence of two cracks, only one is properly healed, especially when using the latter healing agent. Exposure to water immediately after release of the healing agent stimulates the foaming reaction of the polyurethane and ensures a better crack closure.

  9. An ergonomics based design research method for the arrangement of helicopter flight instrument panels.

    Science.gov (United States)

    Alppay, Cem; Bayazit, Nigan

    2015-11-01

    In this paper, we study the arrangement of displays in flight instrument panels of multi-purpose civil helicopters following a user-centered design method based on ergonomics principles. Our methodology can also be described as a user-interface arrangement methodology based on user opinions and preferences. This study can be outlined as gathering user-centered data using two different research methods and then analyzing and integrating the collected data to come up with an optimal instrument panel design. An interview with helicopter pilots formed the first step of our research. In that interview, pilots were asked to provide a quantitative evaluation of basic interface arrangement principles. In the second phase of the research, a paper prototyping study was conducted with same pilots. The final phase of the study entailed synthesizing the findings from interviews and observational studies to formulate an optimal flight instrument arrangement methodology. The primary results that we present in our paper are the methodology that we developed and three new interface arrangement concepts, namely relationship of inseparability, integrated value and locational value. An optimum instrument panel arrangement is also proposed by the researchers. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  10. FPGA-based High-precision Measurement Algorithm for the Ultrasonic Echo Time of Flight

    Institute of Scientific and Technical Information of China (English)

    Bo-xiong WANG; Jin ZHANG

    2010-01-01

    Based on the evaluation of advantages and disadvantages of high-precision digital time interval measuring algorithms, and combined with the principle of the typical time-difference ultrasonic flow measurement,the requirements far the measurement of echo time of flight put forward by the ultrasonic flow measurement are an-alyzed.A new high-precision time interval measurement algorithm is presented, which combines the pulse counting method with the phase delay interpolation. The pulse counting method is used to ensure a large dynamic measuring range, and a double-edge triggering counter is designed to improve the accuracy and reduce the counting quantiza-tion error.The phase delay interpolation is used to reduce the quanti-zation error of pulse counting for further improving the time measure-ment resolution.Test data show that the system for the measurement of the ultrasonic echo time of flight based on this algorithm and im-plemented on an Field Programmable Gate Array(FPGA) needs a rel-atively short time for measurement,and has a measurement error of less than 105 ps.

  11. Attitude determination using a MEMS-based flight information measurement unit.

    Science.gov (United States)

    Ma, Der-Ming; Shiau, Jaw-Kuen; Wang, I-Chiang; Lin, Yu-Heng

    2012-01-01

    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. 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.

  13. Robust Stability Clearance of Flight Control Law Based on Global Sensitivity Analysis

    Directory of Open Access Journals (Sweden)

    Liuli Ou

    2014-01-01

    Full Text Available To validate the robust stability of the flight control system of hypersonic flight vehicle, which suffers from a large number of parametrical uncertainties, a new clearance framework based on structural singular value (μ theory and global uncertainty sensitivity analysis (SA is proposed. In this framework, SA serves as the preprocess of uncertain model to be analysed to help engineers to determine which uncertainties affect the stability of the closed loop system more slightly. By ignoring these unimportant uncertainties, the calculation of μ can be simplified. Instead of analysing the effect of uncertainties on μ which involves solving optimal problems repeatedly, a simpler stability analysis function which represents the effect of uncertainties on closed loop poles is proposed. Based on this stability analysis function, Sobol’s method, the most widely used global SA method, is extended and applied to the new clearance framework due to its suitability for system with strong nonlinearity and input factors varying in large interval, as well as input factors subjecting to random distributions. In this method, the sensitive indices can be estimated via Monte Carlo simulation conveniently. An example is given to illustrate the efficiency of the proposed method.

  14. Innovative hazard detection and avoidance strategy for autonomous safe planetary landing

    Science.gov (United States)

    Jiang, Xiuqiang; Li, Shuang; Tao, Ting

    2016-09-01

    Autonomous hazard detection and avoidance (AHDA) is one of the key technologies for future safe planetary landing missions. In this paper, we address the latest progress on planetary autonomous hazard detection and avoidance technologies. First, the innovative autonomous relay hazard detection and avoidance strategy adopted in Chang'e-3 lunar soft landing mission and its flight results are reported in detail. Second, two new conceptual candidate schemes of hazard detection and avoidance are presented based on the Chang'e-3 AHDA system and the latest developing technologies for the future planetary missions, and some preliminary testing results are also given. Finally, the related supporting technologies for the two candidate schemes above are analyzed.

  15. Autonomous Sub-Pixel Satellite Track Endpoint Determination for Space Based Images

    Energy Technology Data Exchange (ETDEWEB)

    Simms, L M

    2011-03-07

    An algorithm for determining satellite track endpoints with sub-pixel resolution in spaced-based images is presented. The algorithm allows for significant curvature in the imaged track due to rotation of the spacecraft capturing the image. The motivation behind the subpixel endpoint determination is first presented, followed by a description of the methodology used. Results from running the algorithm on real ground-based and simulated spaced-based images are shown to highlight its effectiveness.

  16. Mathematical model of unmanned aerial vehicle used for endurance autonomous monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Chelaru, Teodor-Viorel, E-mail: teodor.chelaru@upb.ro [University POLITEHNICA of Bucharest - Research Center for Aeronautics and Space, Str. Gheorghe Polizu, no. 1, PC 011061, Sector 1, Bucharest (Romania); Chelaru, Adrian, E-mail: achelaru@incas.ro [INCAS -National Institute for Aerospace Research Elie Carafoli, B-dul Iuliu Maniu 220, 061126, Sector 6, Bucharest (Romania)

    2014-12-10

    The paper purpose is to present some aspects regarding the control system of unmanned aerial vehicle - UAV, used to local observations, surveillance and monitoring interest area. The calculus methodology allows a numerical simulation of UAV evolution in bad atmospheric conditions by using nonlinear model, as well as a linear one for obtaining guidance command. The UAV model which will be presented has six DOF (degrees of freedom), and autonomous control system. This theoretical development allows us to build stability matrix, command matrix and control matrix and finally to analyse the stability of autonomous UAV flight. A robust guidance system, based on uncoupled state will be evaluated for different fly conditions and the results will be presented. The flight parameters and guidance will be analysed.

  17. Mathematical model of unmanned aerial vehicle used for endurance autonomous monitoring

    Science.gov (United States)

    Chelaru, Teodor-Viorel; Chelaru, Adrian

    2014-12-01

    The paper purpose is to present some aspects regarding the control system of unmanned aerial vehicle - UAV, used to local observations, surveillance and monitoring interest area. The calculus methodology allows a numerical simulation of UAV evolution in bad atmospheric conditions by using nonlinear model, as well as a linear one for obtaining guidance command. The UAV model which will be presented has six DOF (degrees of freedom), and autonomous control system. This theoretical development allows us to build stability matrix, command matrix and control matrix and finally to analyse the stability of autonomous UAV flight. A robust guidance system, based on uncoupled state will be evaluated for different fly conditions and the results will be presented. The flight parameters and guidance will be analysed.

  18. ISAC time-of-flight system with laser-based calibration

    Energy Technology Data Exchange (ETDEWEB)

    Verzilov, V.A., E-mail: verzilov@triumf.ca

    2015-06-11

    The time-of-flight (TOF) system is available at the ISAC rare isotope facility to measure the energy of stable and radioactive ion beams in the range of 0.5–22 Mev/u. The system, comprised of three secondary electron emission based monitors, is operated with practically all available beam intensities starting from as low as 10{sup 3} ions per second. Recently the system was equipped with the calibration setup based on a 266 nm ultraviolet laser. Laser light interacting with the TOF monitors generates secondary electrons due to the photoelectric effect and acts as a reference beam traveling at a well- known velocity. After calibration, accuracy of energy measurements improved to be better than 0.1%.

  19. Digital Autonomous Terminal Access Communication (DATAC) system

    Science.gov (United States)

    Novacki, Stanley M., III

    1987-01-01

    In order to accommodate the increasing number of computerized subsystems aboard today's more fuel efficient aircraft, the Boeing Co. has developed the DATAC (Digital Autonomous Terminal Access Control) bus to minimize the need for point-to-point wiring to interconnect these various systems, thereby reducing total aircraft weight and maintaining an economical flight configuration. The DATAC bus is essentially a local area network providing interconnections for any of the flight management and control systems aboard the aircraft. The task of developing a Bus Monitor Unit was broken down into four subtasks: (1) providing a hardware interface between the DATAC bus and the Z8000-based microcomputer system to be used as the bus monitor; (2) establishing a communication link between the Z8000 system and a CP/M-based computer system; (3) generation of data reduction and display software to output data to the console device; and (4) development of a DATAC Terminal Simulator to facilitate testing of the hardware and software which transfer data between the DATAC's bus and the operator's console in a near real time environment. These tasks are briefly discussed.

  20. Autonomous Aerobraking Development Software: Phase 2 Summary

    Science.gov (United States)

    Cianciolo, Alicia D.; Maddock, Robert W.; Prince, Jill L.; Bowes, Angela; Powell, Richard W.; White, Joseph P.; Tolson, Robert; O'Shaughnessy, Daniel; Carrelli, David

    2013-01-01

    NASA has used aerobraking at Mars and Venus to reduce the fuel required to deliver a spacecraft into a desired orbit compared to an all-propulsive solution. Although aerobraking reduces the propellant, it does so at the expense of mission duration, large staff, and DSN coverage. These factors make aerobraking a significant cost element in the mission design. By moving on-board the current ground-based tasks of ephemeris determination, atmospheric density estimation, and maneuver sizing and execution, a flight project would realize significant cost savings. The NASA Engineering and Safety Center (NESC) sponsored Phase 1 and 2 of the Autonomous Aerobraking Development Software (AADS) study, which demonstrated the initial feasibility of moving these current ground-based functions to the spacecraft. This paper highlights key state-of-the-art advancements made in the Phase 2 effort to verify that the AADS algorithms are accurate, robust and ready to be considered for application on future missions that utilize aerobraking. The advancements discussed herein include both model updates and simulation and benchmark testing. Rigorous testing using observed flight atmospheres, operational environments and statistical analysis characterized the AADS operability in a perturbed environment.

  1. Magnetic Random Access Memory based non-volatile asynchronous Muller cell for ultra-low power autonomous applications

    Science.gov (United States)

    Di Pendina, G.; Zianbetov, E.; Beigne, E.

    2015-05-01

    Micro and nano electronic integrated circuit domain is today mainly driven by the advent of the Internet of Things for which the constraints are strong, especially in terms of power consumption and autonomy, not only during the computing phases but also during the standby or idle phases. In such ultra-low power applications, the circuit has to meet new constraints mainly linked to its changing energetic environment: long idle phases, automatic wake up, data back-up when the circuit is sporadically turned off, and ultra-low voltage power supply operation. Such circuits have to be completely autonomous regarding their unstable environment, while remaining in an optimum energetic configuration. Therefore, we propose in this paper the first MRAM-based non-volatile asynchronous Muller cell. This cell has been simulated and characterized in a very advanced 28 nm CMOS fully depleted silicon-on-insulator technology, presenting good power performance results due to an extremely efficient body biasing control together with ultra-wide supply voltage range from 160 mV up to 920 mV. The leakage current can be reduced to 154 pA thanks to reverse body biasing. We also propose an efficient standard CMOS bulk version of this cell in order to be compatible with different fabrication processes.

  2. Magnetic Random Access Memory based non-volatile asynchronous Muller cell for ultra-low power autonomous applications

    Energy Technology Data Exchange (ETDEWEB)

    Di Pendina, G., E-mail: gregory.dipendina@cea.fr, E-mail: eldar.zianbetov@cea.fr, E-mail: edith.beigne@cea.fr; Zianbetov, E., E-mail: gregory.dipendina@cea.fr, E-mail: eldar.zianbetov@cea.fr, E-mail: edith.beigne@cea.fr [Univ. Grenoble Alpes, INAC-SPINTEC, F-38000 Grenoble (France); CNRS, SPINTEC, F-38000 Grenoble (France); CEA, INAC-SPINTEC, F-38000 Grenoble (France); Beigne, E., E-mail: gregory.dipendina@cea.fr, E-mail: eldar.zianbetov@cea.fr, E-mail: edith.beigne@cea.fr [Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble (France)

    2015-05-07

    Micro and nano electronic integrated circuit domain is today mainly driven by the advent of the Internet of Things for which the constraints are strong, especially in terms of power consumption and autonomy, not only during the computing phases but also during the standby or idle phases. In such ultra-low power applications, the circuit has to meet new constraints mainly linked to its changing energetic environment: long idle phases, automatic wake up, data back-up when the circuit is sporadically turned off, and ultra-low voltage power supply operation. Such circuits have to be completely autonomous regarding their unstable environment, while remaining in an optimum energetic configuration. Therefore, we propose in this paper the first MRAM-based non-volatile asynchronous Muller cell. This cell has been simulated and characterized in a very advanced 28 nm CMOS fully depleted silicon-on-insulator technology, presenting good power performance results due to an extremely efficient body biasing control together with ultra-wide supply voltage range from 160 mV up to 920 mV. The leakage current can be reduced to 154 pA thanks to reverse body biasing. We also propose an efficient standard CMOS bulk version of this cell in order to be compatible with different fabrication processes.

  3. Dynamic Sliding Mode Control Based on Multi-model Switching Laws for the Depth Control of an Autonomous Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Huanyin Zhou

    2015-07-01

    Full Text Available This manuscript presents an improved control algorithm, called Dynamic Sliding Mode Control based on Multiple Models Switching Laws (DSMC-MMSL, for the control of the depth of the studied Autonomous Underwater Vehicle (AUV system, the diving plane controller of which faces disturbances arising from the coupled states. The diving plane model is strongly coupled with the state variables, such as surge speeds and course angles. To achieve the desired dynamic performance, the proposed algorithm consists of two parts: the diving plane control part and the pitch control part, which is used to avoid large pitch angles. Some direct switching control laws are used for the two parts to avoid some impulse phenomena on the control executions. The error-states exponential decay is recommended to eliminate the chattering on the sliding surface. The DSMC-MMSL controller was successfully implemented and experimentally validated with the studied AUV system designed and built by Shenyang Institute of Automation. The results of some lake trials demonstrated that the depth control performances of the AUV system were as desired, and that the AUV system was robust enough for the coupled state variables under the DSMCMMSL algorithm control.

  4. Biogeography-based combinatorial strategy for efficient autonomous underwater vehicle motion planning and task-time management

    Science.gov (United States)

    Zadeh, S. M.; Powers, D. M. W.; Sammut, K.; Yazdani, A. M.

    2016-12-01

    Autonomous Underwater Vehicles (AUVs) are capable of spending long periods of time for carrying out various underwater missions and marine tasks. In this paper, a novel conflict-free motion planning framework is introduced to enhance underwater vehicle's mission performance by completing maximum number of highest priority tasks in a limited time through a large scale waypoint cluttered operating field, and ensuring safe deployment during the mission. The proposed combinatorial route-path planner model takes the advantages of the Biogeography-Based Optimization (BBO) algorithm toward satisfying objectives of both higher-lower level motion planners and guarantees maximization of the mission productivity for a single vehicle operation. The performance of the model is investigated under different scenarios including the particular cost constraints in time-varying operating fields. To show the reliability of the proposed model, performance of each motion planner assessed separately and then statistical analysis is undertaken to evaluate the total performance of the entire model. The simulation results indicate the stability of the contributed model and its feasible application for real experiments.

  5. Multi-layer Attribute Selection and Classification Algorithm for the Diagnosis of Cardiac Autonomic Neuropathy Based on HRV Attributes

    Directory of Open Access Journals (Sweden)

    Herbert F. Jelinek

    2015-12-01

    Full Text Available Cardiac autonomic neuropathy (CAN poses an important clinical problem, which often remains undetected due difficulty of conducting the current tests and their lack of sensitivity. CAN has been associated with growth in the risk of unexpected death in cardiac patients with diabetes mellitus. Heart rate variability (HRV attributes have been actively investigated, since they are important for diagnostics in diabetes, Parkinson's disease, cardiac and renal disease. Due to the adverse effects of CAN it is important to obtain a robust and highly accurate diagnostic tool for identification of early CAN, when treatment has the best outcome. Use of HRV attributes to enhance the effectiveness of diagnosis of CAN progression may provide such a tool. In the present paper we propose a new machine learning algorithm, the Multi-Layer Attribute Selection and Classification (MLASC, for the diagnosis of CAN progression based on HRV attributes. It incorporates our new automated attribute selection procedure, Double Wrapper Subset Evaluator with Particle Swarm Optimization (DWSE-PSO. We present the results of experiments, which compare MLASC with other simpler versions and counterpart methods. The experiments used our large and well-known diabetes complications database. The results of experiments demonstrate that MLASC has significantly outperformed other simpler techniques.

  6. Droop-Control-Based State-of-Charge Balancing Method for Charging and Discharging Process in Autonomous DC Microgrids

    DEFF Research Database (Denmark)

    Lu, Xiaonan; Sun, Kai; Guerrero, Josep M.

    2014-01-01

    In this paper, a droop control based state-of-charge (SoC) balancing method in autonomous DC microgrids is proposed. Both charging and discharging process have been considered. In particular, in the charging process, the droop coefficient is set to be proportional to SoCn, and in the discharging...... process, the droop coefficient is set to be inversely proportional to SoCn. Since the injected/output power is in inverse-proportion to the droop coefficient, with the proposed method, the energy storage unit (ESU) with higher SoC absorbs less power in the charging process and delivers more power...... in the discharging process. Meanwhile, the ESU with lower SoC absorbs more power in the charging process and delivers less power in the discharging process. Eventually, the SoC and injected/output power in each ESU are equalized. The exponent n for SoC is employed to regulate the balancing speed of the So...

  7. Dynamic Sliding Mode Control Based on Multi-Model Switching Laws for the Depth Control of an Autonomous Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Huanyin Zhou

    2015-07-01

    Full Text Available This manuscript presents an improved control algorithm, called Dynamic Sliding Mode Control based on Multiple Models Switching Laws (DSMC-MMSL, for the control of the depth of the studied Autonomous Underwater Vehicle (AUV system, the diving plane controller of which faces disturbances arising from the coupled states. The diving plane model is strongly coupled with the state variables, such as surge speeds and course angles. To achieve the desired dynamic performance, the proposed algorithm consists of two parts: the diving plane control part and the pitch control part, which is used to avoid large pitch angles. Some direct switching control laws are used for the two parts to avoid some impulse phenomena on the control executions. The error-states exponential decay is recommended to eliminate the chattering on the sliding surface. The DSMC-MMSL controller was successfully implemented and experimentally validated with the studied AUV system designed and built by Shenyang Institute of Automation. The results of some lake trials demonstrated that the depth control performances of the AUV system were as desired, and that the AUV system was robust enough for the coupled state variables under the DSMC-MMSL algorithm control.

  8. Biogeography-Based Combinatorial Strategy for Efficient Autonomous Underwater Vehicle Motion Planning and Task-Time Management

    Institute of Scientific and Technical Information of China (English)

    S.M.Zadeh; D.M.W Powers; K. Sammut; A.M. Yazdani

    2016-01-01

    Autonomous Underwater Vehicles (AUVs) are capable of conducting various underwater missions and marine tasks over long periods of time. In this study, a novel conflict-free motion-planning framework is introduced. This framework enhances AUV mission performance by completing the maximum number of highest priority tasks in a limited time through a large-scale waypoint cluttered operating field and ensuring safe deployment during the mission. The proposed combinatorial route-path-planner model takes advantage of the Biogeography- Based Optimization (BBO) algorithm to satisfy the objectives of both higher- and lower-level motion planners and guarantee the maximization of mission productivity for a single vehicle operation. The performance of the model is investigated under different scenarios, including cost constraints in time-varying operating fields. To demonstrate the reliability of the proposed model, the performance of each motion planner is separately assessed and statistical analysis is conducted to evaluate the total performance of the entire model. The simulation results indicate the stability of the proposed model and the feasibility of its application to real-time experiments.

  9. A Hierarchical Reliability Control Method for a Space Manipulator Based on the Strategy of Autonomous Decision-Making

    Directory of Open Access Journals (Sweden)

    Xin Gao

    2016-01-01

    Full Text Available In order to maintain and enhance the operational reliability of a robotic manipulator deployed in space, an operational reliability system control method is presented in this paper. First, a method to divide factors affecting the operational reliability is proposed, which divides the operational reliability factors into task-related factors and cost-related factors. Then the models describing the relationships between the two kinds of factors and control variables are established. Based on this, a multivariable and multiconstraint optimization model is constructed. Second, a hierarchical system control model which incorporates the operational reliability factors is constructed. The control process of the space manipulator is divided into three layers: task planning, path planning, and motion control. Operational reliability related performance parameters are measured and used as the system’s feedback. Taking the factors affecting the operational reliability into consideration, the system can autonomously decide which control layer of the system should be optimized and how to optimize it using a control level adjustment decision module. The operational reliability factors affect these three control levels in the form of control variable constraints. Simulation results demonstrate that the proposed method can achieve a greater probability of meeting the task accuracy requirements, while extending the expected lifetime of the space manipulator.

  10. Vertical stream curricula integration of problem-based learning using an autonomous vacuum robot in a mechatronics course

    Science.gov (United States)

    Chin, Cheng; Yue, Keng

    2011-10-01

    Difficulties in teaching a multi-disciplinary subject such as the mechatronics system design module in Departments of Mechatronics Engineering at Temasek Polytechnic arise from the gap in experience and skill among staff and students who have different backgrounds in mechanical, computer and electrical engineering within the Mechatronics Department. The departments piloted a new vertical stream curricula model (VSCAM) to enhance student learning in mechatronics system design through integration of educational activities from the first to the second year of the course. In this case study, a problem-based learning (PBL) method on an autonomous vacuum robot in the mechatronics systems design module was proposed to allow the students to have hands-on experience in the mechatronics system design. The proposed works included in PBL consist of seminar sessions, weekly works and project presentation to provide holistic assessment on teamwork and individual contributions. At the end of VSCAM, an integrative evaluation was conducted using confidence logs, attitude surveys and questionnaires. It was found that the activities were quite appreciated by the participating staff and students. Hence, PBL has served as an effective pedagogical framework for teaching multidisciplinary subjects in mechatronics engineering education if adequate guidance and support are given to staff and students.

  11. Real-time drogue recognition and 3D locating for UAV autonomous aerial refueling based on monocular machine vision

    Institute of Scientific and Technical Information of China (English)

    Wang Xufeng; Kong Xingwei; Zhi Jianhui; Chen Yong; Dong Xinmin

    2015-01-01

    Drogue recognition and 3D locating is a key problem during the docking phase of the autonomous aerial refueling (AAR). To solve this problem, a novel and effective method based on monocular vision is presented in this paper. Firstly, by employing computer vision with red-ring-shape feature, a drogue detection and recognition algorithm is proposed to guarantee safety and ensure the robustness to the drogue diversity and the changes in environmental condi-tions, without using a set of infrared light emitting diodes (LEDs) on the parachute part of the dro-gue. Secondly, considering camera lens distortion, a monocular vision measurement algorithm for drogue 3D locating is designed to ensure the accuracy and real-time performance of the system, with the drogue attitude provided. Finally, experiments are conducted to demonstrate the effective-ness of the proposed method. Experimental results show the performances of the entire system in contrast with other methods, which validates that the proposed method can recognize and locate the drogue three dimensionally, rapidly and precisely.

  12. Vision Autonomous Relative Positioning and Orientating Algorithm for Distributed Micro/Nanosatellite Earth Observation System Based on Dual Quaternion

    Directory of Open Access Journals (Sweden)

    Kezhao Li

    2010-01-01

    Full Text Available It is a valid way to analyze the space object real-time movement by using distributed satellite earth observation system, which can provide the stereographic image through the collaboration of the satellites. That relative position and pose estimation is one of the key technologies for distributed micro/nanosatellite earth observation system (DMSEOS. In this paper, on the basis of the attitude dynamics of spacecrafts and the theory of machine vision, an autonomous positioning and orientating algorithm for distributed micro/nanosatellites based on dual quaternion and EKF (extended Kalman filtering is proposed. Firstly, how to represent a line transform unit using dual quaternion is introduced. Then, the feature line point of the line transform unit is defined. And then, on the basis of the attitude dynamics of spacecrafts and the theory of EKF, we build the state and observation equations. Finally, the simulations show that this algorithm is an accurate valid method in positioning and orientating of distributed micro/nanosatellite earth observation system.

  13. Cardiac autonomic nerve distribution and arrhythmia

    Institute of Scientific and Technical Information of China (English)

    Quan Liu; Dongmei Chen; Yonggang Wang; Xin Zhao; Yang Zheng

    2012-01-01

    OBJECTIVE: To analyze the distribution characteristics of cardiac autonomic nerves and to explore the correlation between cardiac autonomic nerve distribution and arrhythmia.DATA RETRIEVAL: A computer-based retrieval was performed for papers examining the distribution of cardiac autonomic nerves, using "heart, autonomic nerve, sympathetic nerve, vagus nerve, nerve distribution, rhythm and atrial fibrillation" as the key words.SELECTION CRITERIA: A total of 165 studies examining the distribution of cardiac autonomic nerve were screened, and 46 of them were eventually included.MAIN OUTCOME MEASURES: The distribution and characteristics of cardiac autonomic nerves were observed, and immunohistochemical staining was applied to determine the levels of tyrosine hydroxylase and acetylcholine transferase (main markers of cardiac autonomic nerve distribution). In addition, the correlation between cardiac autonomic nerve distribution and cardiac arrhythmia was investigated.RESULTS: Cardiac autonomic nerves were reported to exhibit a disordered distribution in different sites, mainly at the surface of the cardiac atrium and pulmonary vein, forming a ganglia plexus. The distribution of the pulmonary vein autonomic nerve was prominent at the proximal end rather than the distal end, at the upper left rather than the lower right, at the epicardial membrane rather than the endocardial membrane, at the left atrium rather than the right atrium, and at the posterior wall rather than the anterior wall. The main markers used for cardiac autonomic nerves were tyrosine hydroxylase and acetylcholine transferase. Protein gene product 9.5 was used to label the immunoreactive nerve distribution, and the distribution density of autonomic nerves was determined using a computer-aided morphometric analysis system.CONCLUSION: The uneven distribution of the cardiac autonomic nerves is the leading cause of the occurrence of arrhythmia, and the cardiac autonomic nerves play an important role in the

  14. Quantitative Autonomic Testing

    OpenAIRE

    Novak, Peter

    2011-01-01

    Disorders associated with dysfunction of autonomic nervous system are quite common yet frequently unrecognized. Quantitative autonomic testing can be invaluable tool for evaluation of these disorders, both in clinic and research. There are number of autonomic tests, however, only few were validated clinically or are quantitative. Here, fully quantitative and clinically validated protocol for testing of autonomic functions is presented. As a bare minimum the clinical autonomic laboratory shoul...

  15. Design of an autonomous teleoperated cargo transporting vehicle for lunar base operations

    Science.gov (United States)

    Holt, James; Lao, Tom; Monali, Nkoy

    1989-01-01

    At the turn of the century NASA plans to begin construction of a lunar base. The base will likely consist of developed areas (i.e., habitation, laboratory, landing and launching sites, power plant) separated from each other due to safety considerations. The Self-Repositioning Track Vehicle (SRTV) was designed to transport cargo between these base facilities. The SRTV operates by using two robotic arms to raise and position segments of track upon which the vehicle travels. The SRTV utilizes the semiautonomous mobility (SAM) method of teleoperation; actuator-controlled interlocking track sections; two robotic arms each with five degrees of freedom; and these materials: titanium for structural members and aluminum for shell members, with the possible use of light-weight, high-strength composites.

  16. Field Study of a Physical Game for Older Adults Based on an Autonomous, Mobile Robot

    DEFF Research Database (Denmark)

    Hansen, Søren Tranberg; Rasmussen, Dorte Malig; Bak, Thomas

    2012-01-01

    This paper presents an initial, qualitative study on how a game based on a mobile robot with an expressive head can be used as a physical activity for elderly. The game is investigated in two independent field studies - one in a nursing home and one in a rehabilitation centre for elderly using...... an open, exploratory approach. An analysis of the interaction is made based on video recordings, observations and qualitative interviews focusing on the potential of the robot as a rehabilitative application. The primary goal of the study is to observe seniors’ acceptance of the robot, to obtain knowledge...

  17. Robust Coordination of Autonomous Systems through Risk-sensitive, Model-based Programming and Execution

    Science.gov (United States)

    2015-10-09

    describe cRMPL, an extension of the model-based program- ming language RMPL [6] that allows missions with state and temporal uncer- tainty, in...14 3.3.1 Temporal constraints . . . . . . . . . . . . . . . . . . . . 15 3.3.2 State constraints...Simple UAV scenario in cRMPL . . . . . . . . . . . . . . . . . . 19 4 Risk-bounded consistency of Probabilistic Temporal Plan Networks 21 4.1

  18. 3D model-based detection and tracking for space autonomous and uncooperative rendezvous

    Science.gov (United States)

    Shang, Yang; Zhang, Yueqiang; Liu, Haibo

    2015-10-01

    In order to fully navigate using a vision sensor, a 3D edge model based detection and tracking technique was developed. Firstly, we proposed a target detection strategy over a sequence of several images from the 3D model to initialize the tracking. The overall purpose of such approach is to robustly match each image with the model views of the target. Thus we designed a line segment detection and matching method based on the multi-scale space technology. Experiments on real images showed that our method is highly robust under various image changes. Secondly, we proposed a method based on 3D particle filter (PF) coupled with M-estimation to track and estimate the pose of the target efficiently. In the proposed approach, a similarity observation model was designed according to a new distance function of line segments. Then, based on the tracking results of PF, the pose was optimized using M-estimation. Experiments indicated that the proposed method can effectively track and accurately estimate the pose of freely moving target in unconstrained environment.

  19. Voluntary autonomous simulator based training in minimally invasive surgery, residents' compliance and reflection

    NARCIS (Netherlands)

    van Empel, P.J.; Verdam, M.G.E.; Strypet, M.; van Rijssen, L.B.; Huirne, J. A.; Scheele, F.; Bonjer, H.J.; Meijerink, W.J.

    2012-01-01

    Background: Knot tying and suturing skills in minimally invasive surgery (MIS) differ markedly from those in open surgery. Appropriate MIS training is mandatory before implementation into practice. The Advanced Suturing Course (ASC) is a structured simulator based training course that includes a 6-w

  20. An Autonomous Learning System of Bengali Characters Using Web-Based Intelligent Handwriting Recognition

    Science.gov (United States)

    Khatun, Nazma; Miwa, Jouji

    2016-01-01

    This research project was aimed to develop an intelligent Bengali handwriting education system to improve the literacy level in Bangladesh. Due to the socio-economical limitation, all of the population does not have the chance to go to school. Here, we developed a prototype of web-based (iPhone/smartphone or computer browser) intelligent…

  1. Towards an Agent-Based, Autonomous Tactical System for C4ISR Operations

    Science.gov (United States)

    2008-12-01

    Collective. 3.1.1 Fusing Streams The Fusing Stream (Figure 4), is very loosely based on the Joint Directors of Laboratories ( JDL ) data fusion...Revisiting the JDL data fusion model II. Proc. 7th Conf. on Information Fu- sion, Stockholm, Sweden, ISIF, 1218-1230. Parasuraman, R., 2000: Designing

  2. Preliminary test results of a flight management algorithm for fuel conservative descents in a time based metered traffic environment. [flight tests of an algorithm to minimize fuel consumption of aircraft based on flight time

    Science.gov (United States)

    Knox, C. E.; Cannon, D. G.

    1979-01-01

    A flight management algorithm designed to improve the accuracy of delivering the airplane fuel efficiently to a metering fix at a time designated by air traffic control is discussed. The algorithm provides a 3-D path with time control (4-D) for a test B 737 airplane to make an idle thrust, clean configured descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path is calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithms and the results of the flight tests are discussed.

  3. Remote Control of an Autonomous Robotic Platform Based on Eye Tracking

    Directory of Open Access Journals (Sweden)

    PASARICA, A.

    2016-11-01

    Full Text Available Eye-tracking devices are currently used for improving communication and psychosocial status among patients with neuro-motor disabilities. This paper presents the experimental implementation of a control system for a robotic platform using eye tracking technology. The main system is based on an eye tracking subsystem that uses the circular Hough transform algorithm. A central processing unit performs the data transmission between the user and the robotic platform. Experimental tests were conducted to determine the device's performances and usability for patients with neuro-motor disabilities. Moreover, the test results were used to determine the control system learning curve. We created a data base containing information on the robotic platform processing time and precision of movement for improving the platform's performances.

  4. A Hybrid Autonomic Computing-Based Approach to Distributed Constraint Satisfaction Problems

    Directory of Open Access Journals (Sweden)

    Abhishek Bhatia

    2015-03-01

    Full Text Available Distributed constraint satisfaction problems (DisCSPs are among the widely endeavored problems using agent-based simulation. Fernandez et al. formulated sensor and mobile tracking problem as a DisCSP, known as SensorDCSP In this paper, we adopt a customized ERE (environment, reactive rules and entities algorithm for the SensorDCSP, which is otherwise proven as a computationally intractable problem. An amalgamation of the autonomy-oriented computing (AOC-based algorithm (ERE and genetic algorithm (GA provides an early solution of the modeled DisCSP. Incorporation of GA into ERE facilitates auto-tuning of the simulation parameters, thereby leading to an early solution of constraint satisfaction. This study further contributes towards a model, built up in the NetLogo simulation environment, to infer the efficacy of the proposed approach.

  5. A Novel Relative Navigation Control Strategy Based on Relation Space Method for Autonomous Underground Articulated Vehicles

    Directory of Open Access Journals (Sweden)

    Fengqian Dou

    2016-01-01

    Full Text Available This paper proposes a novel relative navigation control strategy based on the relation space method (RSM for articulated underground trackless vehicles. In the RSM, a self-organizing, competitive neural network is used to identify the space around the vehicle, and the spatial geometric relationships of the identified space are used to determine the vehicle’s optimal driving direction. For driving control, the trajectories of the articulated vehicles are analyzed, and data-based steering and speed control modules are developed to reduce modeling complexity. Simulation shows that the proposed RSM can choose the correct directions for articulated vehicles in different tunnels. The effectiveness and feasibility of the resulting novel relative navigation control strategy are validated through experiments.

  6. Creative Engineering Based Education with Autonomous Robots Considering Job Search Support

    Science.gov (United States)

    Takezawa, Satoshi; Nagamatsu, Masao; Takashima, Akihiko; Nakamura, Kaeko; Ohtake, Hideo; Yoshida, Kanou

    The Robotics Course in our Mechanical Systems Engineering Department offers “Robotics Exercise Lessons” as one of its Problem-Solution Based Specialized Subjects. This is intended to motivate students learning and to help them acquire fundamental items and skills on mechanical engineering and improve understanding of Robotics Basic Theory. Our current curriculum was established to accomplish this objective based on two pieces of research in 2005: an evaluation questionnaire on the education of our Mechanical Systems Engineering Department for graduates and a survey on the kind of human resources which companies are seeking and their expectations for our department. This paper reports the academic results and reflections of job search support in recent years as inherited and developed from the previous curriculum.

  7. Case-Based Parameter Selection for Plans: Coordinating Autonomous Vehicle Teams

    Science.gov (United States)

    2014-10-01

    Solution[] // A vector of parameter settings for q Legend : Nq // q’s k-Neighborhood of cases s // A parameter among those in q’s predicted solution S V otes...Case-based game play in the robocup four-legged league : Part I The theoretical model. In: RoboCup 2003: Robot Soccer World Cup VII. pp. 739–747 (2003) 7

  8. An XML-Based Mission Command Language for Autonomous Underwater Vehicles (AUVs)

    Science.gov (United States)

    2003-06-01

    for creating other languages) that is used to create markup languages, such as Hypertext Markup Language (HTML).” (From Deitel , Deitel , Nieto, Lin...text, or any other text-based document. ( Deitel , Deitel , Neito, Lin, and Sadhu, 2001) One benefit of using XSLT for such a task is that XSLT has none...allows the user to select Execution Program: there are two different programs for the execution level (one in C and the other in Java ), so the users

  9. Toward autonomous surface-based infrared remote sensing of polar clouds: cloud-height retrievals

    Science.gov (United States)

    Rowe, Penny M.; Cox, Christopher J.; Walden, Von P.

    2016-08-01

    Polar regions are characterized by their remoteness, making measurements challenging, but an improved knowledge of clouds and radiation is necessary to understand polar climate change. Infrared radiance spectrometers can operate continuously from the surface and have low power requirements relative to active sensors. Here we explore the feasibility of retrieving cloud height with an infrared spectrometer that would be designed for use in remote polar locations. Using a wide variety of simulated spectra of mixed-phase polar clouds at varying instrument resolutions, retrieval accuracy is explored using the CO2 slicing/sorting and the minimum local emissivity variance (MLEV) methods. In the absence of imposed errors and for clouds with optical depths greater than ˜ 0.3, cloud-height retrievals from simulated spectra using CO2 slicing/sorting and MLEV are found to have roughly equivalent high accuracies: at an instrument resolution of 0.5 cm-1, mean biases are found to be ˜ 0.2 km for clouds with bases below 2 and -0.2 km for higher clouds. Accuracy is found to decrease with coarsening resolution and become worse overall for MLEV than for CO2 slicing/sorting; however, the two methods have differing sensitivity to different sources of error, suggesting an approach that combines them. For expected errors in the atmospheric state as well as both instrument noise and bias of 0.2 mW/(m2 sr cm-1), at a resolution of 4 cm-1, average retrieval errors are found to be less than ˜ 0.5 km for cloud bases within 1 km of the surface, increasing to ˜ 1.5 km at 4 km. This sensitivity indicates that a portable, surface-based infrared radiance spectrometer could provide an important complement in remote locations to satellite-based measurements, for which retrievals of low-level cloud are challenging.

  10. Stability boundaries analysis of non-autonomous systems with resonant solutions based on subharmonic Melnikov functions, Proceedings of the 2004 American Control Conference

    OpenAIRE

    Susuki, Yoshihiko; Hikihara Takashi

    2004-01-01

    This paper addresses stability boundaries in non-autonomous systems. An analytical criterion for stability boundaries in one degree of freedom (time-periodic) perturbed Hamiltonian systems was recently proposed. The criterion evaluates basin boundaries of non-resonant solutions. This paper discusses the stability boundaries with respect to the resonant solutions based on the above result and subharmonic Melnikov functions. At first one degree of freedom perturbed (time-independent) Hamiltonia...

  11. 3D simulation of A-SMGCS surface movement based on FlightGear%基于FlightGear的A-SMGCS场面活动三维仿真

    Institute of Scientific and Technical Information of China (English)

    唐勇; 胡明华; 吴宏刚; 黄忠涛; 徐自励; 何东林

    2012-01-01

    针对A-SMGCS系统场面活动三维仿真问题,提出一种以开源模拟飞行器FlightGear为场景仿真平台,以实时ADS-B监视数据为驱动,以Linux为操作平台的机场场面活动三维仿真系统设计新方法.仿真系统按照实际机场模型进行机场布局设计,飞机、航站楼、塔台三维建模,地形数据生成,对真实机场环境进行了完整建模.由于ADS-B监视数据缺少飞机姿态信息,提出一种根据位置数据推算出姿态信息的新方法.首先把ADS-B监视数据进行航迹卡尔曼滤波,然后根据飞机前后两个位置的空间连线矢量计算飞行姿态.通过FlightGear多机网络数据接口导入飞机定位数据与姿态数据驱动飞机模型运动,实现了对飞机运动的六自由度仿真.仿真结果表明,该系统能逼真、准确再现真实机场飞机实时活动情况.由于完全基于开源软件设计,该系统低成本实现了对场面活动的实时三维仿真.%A new method to design a 3D surface movement simulation system for A-SMGCS based on Linux operation system and FilightGear flight simulator was proposed. The simulation system was driven by real-time track data of ADS-B. An airport model was built up according to a real airport prototype by modeling of aircrafts, airport layout, terminal, tower and terrain. Because ADS-B track data had no flight attitude data, an algorithm to extract flight attitude from a space vector, which was connected by two pre and post track points, was proposed. Six degrees of freedom (6-DOF) aircraft movement simulation was realized by importing position and attitude data into FlightGear through its multiplayer interface to drive aircraft models. The simulation results show that, the system can simulate surface movement accurately and realistically. The simulation system is low-cost because it is based on free, open source software.

  12. Exploring Human Mobility Patterns Based on Location Information of US Flights

    CERN Document Server

    Jiang, Bin

    2011-01-01

    A range of early studies have been conducted to illustrate human mobility patterns using different tracking data, such as dollar notes, cell phones and taxicabs. Here, we explore human mobility patterns based on massive tracking data of US flights. Both topological and geometric properties are examined in detail. We found that topological properties, such as traffic volume (between airports) and degree of connectivity (of individual airports), including both in- and outdegrees, follow a power law distribution but not a geometric property like travel lengths. The travel lengths exhibit an exponential distribution rather than a power law with an exponential cutoff as previous studies illustrated. We further simulated human mobility on the established topologies of airports with various moving behaviors and found that the mobility patterns are mainly attributed to the underlying binary topology of airports and have little to do with other factors, such as moving behaviors and geometric distances. Apart from the ...

  13. High performance jet-engine flight test data base for HSR

    Science.gov (United States)

    Kelly, Jeffrey

    1992-01-01

    The primary acoustic priority of the flight test data base for HSR is the validation of the NASA Aircraft Noise Prediction Program (ANOPP) and other source noise codes. Also, the noise measurements are an important support function for the High Lift Program devoted to HSR. Another concern that will be addressed is a possible noise problem 7-20 miles from take-off during climbout. The attention arises from the higher speeds envisioned for the HSCT compared to conventional aircraft causing levels to increase because of Doppler amplification in conjunction with high source levels due to jet noise. An attempt may be made to measure airframe noise for the F-16XL test which would provide an assessment of this noise component for delta wing aircraft.

  14. Neutral particle energy analyser based on time of flight technique for EXTRAP-T2R

    Energy Technology Data Exchange (ETDEWEB)

    Cecconello, M. [Royal Inst. of Tech., Stockholm (Sweden). Div. of Fusion Plasma Physics; Costa, S.; Murari, A.; Barzon, A. [Consorzio RFX, Padova (Italy)

    2001-07-01

    An important and not well-understood problem in the Reversed Field Pinch configuration is the anomalous ion heating. In all Ohmically heated RFPs, the ion temperature has been experimentally observed to be higher than can be accounted for by equilibration of energy from an Ohmically heated electron population. The mechanism driving the ions to such high energies is still debated. Different possible explanations have been investigated: kinetic Alfven waves turbulence, MHD relaxation processes and the excitation of an ion electrostatic wave by supra-thermal electrons. The measurement of the ion temperature is important in order to evaluate confinement. Furthermore, measurements can provide information on the mechanism behind the anomalous ion heating. The ion temperature is calculated from the neutral particles energy spectrum obtained by a neutral particles energy analyser based on the time of flight specifically developed for EXTRAP - T2R and here described in detail.

  15. QFT control based on zero phase error compensation for flight simulator

    Institute of Scientific and Technical Information of China (English)

    Liu Jinkun; He Yuzhu

    2007-01-01

    To improve the robustness of high-precision servo systems, quantitative feedback theory (QFT) which aims to achieve a desired robust design over a specified region of plant uncertainty is proposed. The robust design problem can be solved using QFT but it fails to guarantee a high precision tracking. This problem is solved by a robust digital QFT control scheme based on zero phase error (ZPE) feed forward compensation. This scheme consists of two parts: a QFr controller in the closed-loop system and a ZPE feed-forward compensator. Digital QFT controller is designed to overcome the uncertainties in the system. Digital ZPE feed forward controller is used to improve the tracking precision. Simulation and real-time examples for flight simulator servo system indicate that this control scheme can guarantee both high robust performance and high position tracking precision.

  16. Objective Error Criterion for Evaluation of Mapping Accuracy Based on Sensor Time-of-Flight Measurements

    Directory of Open Access Journals (Sweden)

    Billur Barshan

    2008-12-01

    Full Text Available An objective error criterion is proposed for evaluating the accuracy of maps of unknown environments acquired by making range measurements with different sensing modalities and processing them with different techniques. The criterion can also be used for the assessment of goodness of fit of curves or shapes fitted to map points. A demonstrative example from ultrasonic mapping is given based on experimentally acquired time-of-flight measurements and compared with a very accurate laser map, considered as absolute reference. The results of the proposed criterion are compared with the Hausdorff metric and the median error criterion results. The error criterion is sufficiently general and flexible that it can be applied to discrete point maps acquired with other mapping techniques and sensing modalities as well.

  17. Interface Management for a NASA Flight Project Using Model-Based Systems Engineering (MBSE)

    Science.gov (United States)

    Vipavetz, Kevin; Shull, Thomas A.; Infeld, Samatha; Price, Jim

    2016-01-01

    The goal of interface management is to identify, define, control, and verify interfaces; ensure compatibility; provide an efficient system development; be on time and within budget; while meeting stakeholder requirements. This paper will present a successful seven-step approach to interface management used in several NASA flight projects. The seven-step approach using Model Based Systems Engineering will be illustrated by interface examples from the Materials International Space Station Experiment-X (MISSE-X) project. The MISSE-X was being developed as an International Space Station (ISS) external platform for space environmental studies, designed to advance the technology readiness of materials and devices critical for future space exploration. Emphasis will be given to best practices covering key areas such as interface definition, writing good interface requirements, utilizing interface working groups, developing and controlling interface documents, handling interface agreements, the use of shadow documents, the importance of interface requirement ownership, interface verification, and product transition.

  18. An autonomous image based approach for detecting glacial lake outburst floods

    Science.gov (United States)

    Koschitzki, R.; Schwalbe, E.; Maas, H.-G.

    2014-06-01

    The potential danger caused by glacier margin lakes and the related risk of glacier lake outburst floods (GLOF) increases constantly due to glaciers retreating in many parts of the world. Reasons for this development are on the one hand the new formation and enlargement of glacier margin lakes due to melt water. On the other hand, retreating and thinning glacier tongues lead to a decrease of the back pressure against the dammed glacier lakes. The paper describes the design of a photogrammetric GLOF monitoring system, based on monoscopic image sequence analysis for automatic detection of water level changes. The presented approach for measuring the water line in an image sequence is based on directional edge detection in LoG-filtered image data. After that, the water level is determined by a transformation of image measurements into object space based on orientation parameters of the camera and a geo-referenced lake basin model. The model can for instance be determined by photogrammetric methods after a GLOF; it may also be determined portion-wise by analysing shore lines at various water levels. Camera orientation parameters are determined by a local GPS-supported photogrammetric network. Comparing the determined water level changes with reference data provided by a water gauge, the precision is estimated in the order of one decimetre. A major challenge is the automatic detection of the water line in image sequences under varying light and visibility conditions. The paper will also discuss promising approaches such as multispectral images as well as a statistical analysis of grey value changes over short image sequences to eliminate disturbing reflections on the rough water surface.

  19. A Microcomputer-Based Controller for an Autonomous Underwater Vehicle (AUV)

    Science.gov (United States)

    1990-03-01

    possible dynamic situations. In the case of the AUV, a model based on the United States Navy’s Swimmer Delivery Vehicle is used. This model is...mul(Matrix MI, int rl, int cl, Matrix M2, imt r2, int c2, Matrix M3); void control8( double *mstate, double *inputs, double ordereddepth, double...12 states depicted in Table 2. of this thesis using the dynamic equations of motion modeled after the U.S. Navy’s Swimmer Delivery Vehicle. The

  20. Localization of periodic orbits of autonomous systems based on high-order extremum conditions

    Directory of Open Access Journals (Sweden)

    Starkov Konstantin E.

    2004-01-01

    Full Text Available This paper gives localization and nonexistence conditions of periodic orbits in some subsets of the state space. Mainly, our approach is based on high-order extremum conditions, on high-order tangency conditions of a nonsingular solution of a polynomial system with an algebraic surface, and on some ideas related to algebraically-dependent polynomials. Examples of the localization analysis of periodic orbits are presented including the Blasius equations, the generalized mass action (GMA system, and the mathematical model of the chemical reaction with autocatalytic step.

  1. Stochastic sensitivity analysis of periodic attractors in non-autonomous nonlinear dynamical systems based on stroboscopic map

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Kong-Ming, E-mail: kmguo@xidian.edu.cn [School of Electromechanical Engineering, Xidian University, P.O. Box 187, Xi' an 710071 (China); Jiang, Jun, E-mail: jun.jiang@mail.xjtu.edu.cn [State Key Laboratory for Strength and Vibration, Xi' an Jiaotong University, Xi' an 710049 (China)

    2014-07-04

    To apply stochastic sensitivity function method, which can estimate the probabilistic distribution of stochastic attractors, to non-autonomous dynamical systems, a 1/N-period stroboscopic map for a periodic motion is constructed in order to discretize the continuous cycle into a discrete one. In this way, the sensitivity analysis of a cycle for discrete map can be utilized and a numerical algorithm for the stochastic sensitivity analysis of periodic solutions of non-autonomous nonlinear dynamical systems under stochastic disturbances is devised. An external excited Duffing oscillator and a parametric excited laser system are studied as examples to show the validity of the proposed method. - Highlights: • A method to analyze sensitivity of stochastic periodic attractors in non-autonomous dynamical systems is proposed. • Probabilistic distribution around periodic attractors in an external excited Φ{sup 6} Duffing system is obtained. • Probabilistic distribution around a periodic attractor in a parametric excited laser system is determined.

  2. Autonomous Parameter Adjustment for SSVEP-Based BCIs with a Novel BCI Wizard.

    Science.gov (United States)

    Gembler, Felix; Stawicki, Piotr; Volosyak, Ivan

    2015-01-01

    Brain-Computer Interfaces (BCIs) transfer human brain activities into computer commands and enable a communication channel without requiring movement. Among other BCI approaches, steady-state visual evoked potential (SSVEP)-based BCIs have the potential to become accurate, assistive technologies for persons with severe disabilities. Those systems require customization of different kinds of parameters (e.g., stimulation frequencies). Calibration usually requires selecting predefined parameters by experienced/trained personnel, though in real-life scenarios an interface allowing people with no experience in programming to set up the BCI would be desirable. Another occurring problem regarding BCI performance is BCI illiteracy (also called BCI deficiency). Many articles reported that BCI control could not be achieved by a non-negligible number of users. In order to bypass those problems we developed a SSVEP-BCI wizard, a system that automatically determines user-dependent key-parameters to customize SSVEP-based BCI systems. This wizard was tested and evaluated with 61 healthy subjects. All subjects were asked to spell the phrase "RHINE WAAL UNIVERSITY" with a spelling application after key parameters were determined by the wizard. Results show that all subjects were able to control the spelling application. A mean (SD) accuracy of 97.14 (3.73)% was reached (all subjects reached an accuracy above 85% and 25 subjects even reached 100% accuracy).

  3. Autonomic Management of Object Replication for FT-CORBA Based Intelligent Transportation Systems

    Science.gov (United States)

    Suh, Woonsuk; Lee, Eunseok

    Intelligent Transportation Systems (ITS) comprises the electronics, communications or information processing used singly or integrated to improve the efficiency or safety of surface transportation. Accordingly, the ITS has to perform collection, management, and provision of real time transport information reliably. It can be deployed based on the Common Object Request Broker Architecture (CORBA) of the Object Management Group (OMG) because it consists of many interconnected heterogeneous systems deployed by independent organizations. Fault Tolerant CORBA (FT-CORBA) supports real time requirement of transport information stably through redundancy by replication of server objects. However, object replication, management, and related protocols of FT-CORBA require extra system resources of CPU and memory, and can degrade the system performance both locally and as a whole. This paper proposes an architecture to enhance performance of FT-CORBA based ITS in terms of CPU and memory by managing object replication adaptively during system operation with an agent. The application of the agent is expected to support fault tolerance of real ITS efficiently.

  4. Power quality control of an autonomous wind-diesel power system based on hybrid intelligent controller.

    Science.gov (United States)

    Ko, Hee-Sang; Lee, Kwang Y; Kang, Min-Jae; Kim, Ho-Chan

    2008-12-01

    Wind power generation is gaining popularity as the power industry in the world is moving toward more liberalized trade of energy along with public concerns of more environmentally friendly mode of electricity generation. The weakness of wind power generation is its dependence on nature-the power output varies in quite a wide range due to the change of wind speed, which is difficult to model and predict. The excess fluctuation of power output and voltages can influence negatively the quality of electricity in the distribution system connected to the wind power generation plant. In this paper, the authors propose an intelligent adaptive system to control the output of a wind power generation plant to maintain the quality of electricity in the distribution system. The target wind generator is a cost-effective induction generator, while the plant is equipped with a small capacity energy storage based on conventional batteries, heater load for co-generation and braking, and a voltage smoothing device such as a static Var compensator (SVC). Fuzzy logic controller provides a flexible controller covering a wide range of energy/voltage compensation. A neural network inverse model is designed to provide compensating control amount for a system. The system can be optimized to cope with the fluctuating market-based electricity price conditions to lower the cost of electricity consumption or to maximize the power sales opportunities from the wind generation plant.

  5. Autonomous parameter adjustment for SSVEP-based BCIs with a novel BCI Wizard

    Directory of Open Access Journals (Sweden)

    Felix eGembler

    2015-12-01

    Full Text Available Brain-computer interfaces (BCIs transfer human brain activities into computer commands and enable a communication channel without requiring movement.Among other BCI approaches, steady-state visual evoked potential (SSVEP-based BCIs have the potential to become accurate, assistive technologies for persons with severe disabilities.Those systems require customization of different kinds of parameters (e.g. stimulation frequencies. Calibration usually requires selecting predefined parameters by experienced/trained personnel, though in real-life scenarios an interface allowing people with no experience in programming to set up the BCI would be desirable. Another occurring problem regarding BCI performance is BCI illiteracy (also called BCI deficiency. Many articles reported that BCI control could not be achieved by a non-negligible number of users. In order to bypass those problems we developed a SSVEP-BCI wizard, a system that automatically determines user-dependent key-parameters to customize SSVEP-based BCI systems. This wizard was tested and evaluated with 61 healthy subjects. All subjects were asked to spell the phrase ``RHINE WAAL UNIVERSITY'' with a spelling application after key parameters were determined by the wizard. Results show that all subjects were able to control the spelling application. A mean (SD accuracy of 97.14 (3.73% was reached (all subjects reached an accuracy above 85% and 25 subjects even reached 100% accuracy.

  6. Autonomous mobile robot teams

    Science.gov (United States)

    Agah, Arvin; Bekey, George A.

    1994-01-01

    This paper describes autonomous mobile robot teams performing tasks in unstructured environments. The behavior and the intelligence of the group is distributed, and the system does not include a central command base or leader. The novel concept of the Tropism-Based Cognitive Architecture is introduced, which is used by the robots in order to produce behavior transforming their sensory information to proper action. The results of a number of simulation experiments are presented. These experiments include worlds where the robot teams must locate, decompose, and gather objects, and defend themselves against hostile predators, while navigating around stationary and mobile obstacles.

  7. A Self-Tuning Proportional-Integral-Derivative Controller for an Autonomous Underwater Vehicle, Based On Taguchi Method

    Directory of Open Access Journals (Sweden)

    M, Santhakumar

    2010-01-01

    Full Text Available Problem statement: Conventional Proportional-Integral-Derivative (PID controllers exhibit moderately good performance once the PID gains are properly tuned. However, when the dynamic characteristics of the system are time dependent or the operating conditions of the system vary, it is necessary to retune the gains to obtain desired performance. This situation has renewed the interest of researchers and practitioners in PID control. Self-tuning of PID controllers has emerged as a new and active area of research with the advent and easy availability of algorithms and computers. This study discusses self-tuning (auto-tuning algorithm for control of autonomous underwater vehicles. Approach: Self-tuning mechanism will avoid time consuming manual tuning of controllers and promises better results by providing optimal PID controller settings as the system dynamics or operating points change. Most of the self-tuning methods available in the literature were based on frequency response characteristics and search methods. In this study, we proposed a method based on Taguchi’s robust design method for self-tuning of an autonomous underwater vehicle controller. The algorithm, based on this method, tuned the controller gains optimally and robustly in real time with less computation effort by using desired and actual state variables. It can be used for the Single-Input Single-Output (SISO systems as well as Multi-Input Multi-Output (MIMO systems without mathematical models of plants. Results: A simulation study of the AUV control on the horizontal plane (yaw plane control was used to demonstrate and validate the performance and effectiveness of the proposed scheme. Simulation results of the proposed self-tuning scheme are compared with the conventional PID controllers which are tuned by Ziegler-Nichols (ZN and Taguchi’s tuning methods. These results showed that the Integral Square Error (ISE is significantly reduced from the conventional

  8. Computer program to simulate digital computer based longitudinal flight control laws in a high performance aircraft

    OpenAIRE

    Carter, James Robert

    1983-01-01

    Approved for public release; distribution unlimited The IEH Company's Continuous Systems Modeling Program was used to simulate the longitudinal flight control system of the F/A-18 aircraft. The model is intended for use in investigations cf aircraft response to flight conditions which approach spin or stall and is restricted to the automatic flaps up (AFU) flight mode. Program outputs include stabilator deflection, leading and trailing edge flap positions, and cress-ax...

  9. Design and Implementation of a Fully Autonomous UAV's Navigator Based on Omni-directional Vision System

    Directory of Open Access Journals (Sweden)

    Seyed Mohammadreza Kasaei

    2011-12-01

    Full Text Available Unmanned Aerial Vehicles (UAVs are the subject of an increasing interest in many applications . UAVs are seeing more widespread use in military, scenic, and civilian sectors in recent years. Autonomy is one of the major advantages of these vehicles. It is then necessary to develop particular sensor in order to provide efficient navigation functions. The helicopter has been stabilized with visual information through the control loop. Omni directional vision can be a useful sensor for this propose. It can be used as the only sensor or as complementary sensor. In this paper , we propose a novel method for path planning on an UAV based on electrical potential .We are using an omni directional vision system for navigating and path planning.

  10. A survey of autonomous vision-based See and Avoid for Unmanned Aircraft Systems

    Science.gov (United States)

    Mcfadyen, Aaron; Mejias, Luis

    2016-01-01

    This paper provides a comprehensive review of the vision-based See and Avoid problem for unmanned aircraft. The unique problem environment and associated constraints are detailed, followed by an in-depth analysis of visual sensing limitations. In light of such detection and estimation constraints, relevant human, aircraft and robot collision avoidance concepts are then compared from a decision and control perspective. Remarks on system evaluation and certification are also included to provide a holistic review approach. The intention of this work is to clarify common misconceptions, realistically bound feasible design expectations and offer new research directions. It is hoped that this paper will help us to unify design efforts across the aerospace and robotics communities.

  11. A novel autonomous real-time position method based on polarized light and geomagnetic field

    Science.gov (United States)

    Wang, Yinlong; Chu, Jinkui; Zhang, Ran; Wang, Lu; Wang, Zhiwen

    2015-04-01

    Many animals exploit polarized light in order to calibrate their magnetic compasses for navigation. For example, some birds are equipped with biological magnetic and celestial compasses enabling them to migrate between the Western and Eastern Hemispheres. The Vikings' ability to derive true direction from polarized light is also widely accepted. However, their amazing navigational capabilities are still not completely clear. Inspired by birds' and Vikings' ancient navigational skills. Here we present a combined real-time position method based on the use of polarized light and geomagnetic field. The new method works independently of any artificial signal source with no accumulation of errors and can obtain the position and the orientation directly. The novel device simply consists of two polarized light sensors, a 3-axis compass and a computer. The field experiments demonstrate device performance.

  12. A novel autonomous real-time position method based on polarized light and geomagnetic field.

    Science.gov (United States)

    Wang, Yinlong; Chu, Jinkui; Zhang, Ran; Wang, Lu; Wang, Zhiwen

    2015-04-08

    Many animals exploit polarized light in order to calibrate their magnetic compasses for navigation. For example, some birds are equipped with biological magnetic and celestial compasses enabling them to migrate between the Western and Eastern Hemispheres. The Vikings' ability to derive true direction from polarized light is also widely accepted. However, their amazing navigational capabilities are still not completely clear. Inspired by birds' and Vikings' ancient navigational skills. Here we present a combined real-time position method based on the use of polarized light and geomagnetic field. The new method works independently of any artificial signal source with no accumulation of errors and can obtain the position and the orientation directly. The novel device simply consists of two polarized light sensors, a 3-axis compass and a computer. The field experiments demonstrate device performance.

  13. Stability Control of Propeller Autonomous Underwater Vehicle Based on Combined Sections Method

    Directory of Open Access Journals (Sweden)

    Qi Duo

    2015-09-01

    Full Text Available Learning from the motion principle of quadrotor, a symmetric propeller AUV, which has small size and low velocity is designed. Compared with the AUV equipped with rudders, it has better maneuverability and manipulation at low velocity. According to the Newton-Euler method, the 6 DOF kinematic model and dynamic model of the propeller AUV are established. A stability controller that consists of 3 different PID controllers is designed. It makes the depth and attitude angle as trigger conditions, and the relevant controller is chosen in different moving process. The simulation experiments simulate ideal motion state and disturbed motion state, and experiments results show that the stability controller based on combined sections method can make the best of mature technology of PID, and meet the control requirements in different stages. It has a higher respond speed and accuracy, improving the stability of the propeller AUV under the disturbance of complex ocean currents.

  14. Coordinate control of initiative mating device for autonomous underwater vehicle based on TDES

    Institute of Scientific and Technical Information of China (English)

    YAN Zhe-ping; HOU Shu-ping

    2005-01-01

    A novel initiative mating device, which has four 2-degree manipulators around the mating skirt, is proposed to mate between a skirt of AUV (autonomons underwater vehicle) and a disabled submarine. The primary function of the device is to keep exact mating between skirt and disabled submarine in a badly sub sea environment. According to the characteristic of rescue, an automaton model is brought forward to describe the mating proceed between AUV and manipulators. The coordinated control is implemented by the TDES(time discrete event system).After taking into account the time problem, it is a useful method to control mating by simulation testing. The result shows that it reduces about 70 seconds after using intelligent co-ordinate control based on TDES through the whole mating procedure.

  15. Parallel Neural Network-Based Motion Controller for Autonomous Underwater Vehicles

    Institute of Scientific and Technical Information of China (English)

    GAN Yong; WANG Li-rong; WAN Lei; XU Yu-ru

    2005-01-01

    A parallel neural network-based controller (PNNC) is presented for the motion control of underwater vehicles in this paper. It consists of a real-time part, a self-learning part and a desired-state programmer, and it is different from normal adaptive neural network controller in structure. Owing to the introduction of the self-learning part, on-line learning can be performed without sample data in several sample periods, resulting in high learning speed of the controller and good control performance. The desired-state programmer is utilized to obtain better learning samples of the neural network to keep the stability of the controller. The developed controller is applied to the 4-degree of freedom control of the AUV "IUV-IV" and is successful on the simulation platform. The control performance is also compared with that of neural network controller with different structures such as normal adaptive neural network and different learning methods. Current effects and surge velocity control are also included to demonstrate the controller's performance. It is shown that the PNNC has a great possibility to solve the problems in the control system design of underwater vehicles.

  16. Multi-Wavelength Based Optical Density Sensor for Autonomous Monitoring of Microalgae.

    Science.gov (United States)

    Jia, Fei; Kacira, Murat; Ogden, Kimberly L

    2015-09-02

    A multi-wavelength based optical density sensor unit was designed, developed, and evaluated to monitor microalgae growth in real time. The system consisted of five main components including: (1) laser diode modules as light sources; (2) photodiodes as detectors; (3) driver circuit; (4) flow cell; and (5) sensor housing temperature controller. The sensor unit was designed to be integrated into any microalgae culture system for both real time and non-real time optical density measurements and algae growth monitoring applications. It was shown that the sensor unit was capable of monitoring the dynamics and physiological changes of the microalgae culture in real-time. Algae biomass concentration was accurately estimated with optical density measurements at 650, 685 and 780 nm wavelengths used by the sensor unit. The sensor unit was able to monitor cell concentration as high as 1.05 g·L(-1) (1.51 × 10⁸ cells·mL(-1)) during the culture growth without any sample preparation for the measurements. Since high cell concentrations do not need to be diluted using the sensor unit, the system has the potential to be used in industrial microalgae cultivation systems for real time monitoring and control applications that can lead to improved resource use efficiency.

  17. Cardiac autonomic changes in middle-aged women: identification based on principal component analysis.

    Science.gov (United States)

    Trevizani, Gabriela A; Nasario-Junior, Olivassé; Benchimol-Barbosa, Paulo R; Silva, Lilian P; Nadal, Jurandir

    2016-07-01

    The purpose of this study was to investigate the application of the principal component analysis (PCA) technique on power spectral density function (PSD) of consecutive normal RR intervals (iRR) aiming at assessing its ability to discriminate healthy women according to age groups: young group (20-25 year-old) and middle-aged group (40-60 year-old). Thirty healthy and non-smoking female volunteers were investigated (13 young [mean ± SD (median): 22·8 ± 0·9 years (23·0)] and 17 Middle-aged [51·7 ± 5·3 years (50·0)]). The iRR sequence was collected during ten minutes, breathing spontaneously, in supine position and in the morning, using a heart rate monitor. After selecting an iRR segment (5 min) with the smallest variance, an auto regressive model was used to estimate the PSD. Five principal component coefficients, extracted from PSD signals, were retained for analysis according to the Mahalanobis distance classifier. A threshold established by logistic regression allowed the separation of the groups with 100% specificity, 83·2% sensitivity and 93·3% total accuracy. The PCA appropriately classified two groups of women in relation to age (young and Middle-aged) based on PSD analysis of consecutive normal RR intervals.

  18. Multi-Wavelength Based Optical Density Sensor for Autonomous Monitoring of Microalgae

    Science.gov (United States)

    Jia, Fei; Kacira, Murat; Ogden, Kimberly L.

    2015-01-01

    A multi-wavelength based optical density sensor unit was designed, developed, and evaluated to monitor microalgae growth in real time. The system consisted of five main components including: (1) laser diode modules as light sources; (2) photodiodes as detectors; (3) driver circuit; (4) flow cell; and (5) sensor housing temperature controller. The sensor unit was designed to be integrated into any microalgae culture system for both real time and non-real time optical density measurements and algae growth monitoring applications. It was shown that the sensor unit was capable of monitoring the dynamics and physiological changes of the microalgae culture in real-time. Algae biomass concentration was accurately estimated with optical density measurements at 650, 685 and 780 nm wavelengths used by the sensor unit. The sensor unit was able to monitor cell concentration as high as 1.05 g·L−1 (1.51 × 108 cells·mL−1) during the culture growth without any sample preparation for the measurements. Since high cell concentrations do not need to be diluted using the sensor unit, the system has the potential to be used in industrial microalgae cultivation systems for real time monitoring and control applications that can lead to improved resource use efficiency. PMID:26364640

  19. Chaotic Path Planner of Autonomous Mobile Robots Based on the Standard Map for Surveillance Missions

    Directory of Open Access Journals (Sweden)

    Caihong Li

    2015-01-01

    Full Text Available This paper proposes a fusion iterations strategy based on the Standard map to generate a chaotic path planner of the mobile robot for surveillance missions. The distances of the chaotic trajectories between the adjacent iteration points which are produced by the Standard map are too large for the robot to track. So a fusion iterations strategy combined with the large region iterations and the small grids region iterations is designed to resolve the problem. The small region iterations perform the iterations of the Standard map in the divided small grids, respectively. It can reduce the adjacent distances by dividing the whole surveillance workspace into small grids. The large region iterations combine all the small grids region iterations into a whole, switch automatically among the small grids, and maintain the chaotic characteristics of the robot to guarantee the surveillance missions. Compared to simply using the Standard map in the whole workspace, the proposed strategy can decrease the adjacent distances according to the divided size of the small grids and is convenient for the robot to track.

  20. 大学英语网络自主学习中的元认知策略培养研究%Research of the training of the metacognitive strategy in the Web-based College English autonomous learning

    Institute of Scientific and Technical Information of China (English)

    贺一舟

    2012-01-01

    针对当前大学英语网络自主学习中的元认知策略缺失,重点探讨了如何在大学英语网络自主学习中培养学习主体的元认知策略,以提高大学英语网络自主学习的效率,真正实现大学英语教学模式的变革与创新。%Web-based autonomous learning is the extension and expansion of college English classroom instruction.To deal with the lack of metacognitive strategy in web-based college English autonomous learning,this article discusses the development in web-based college English autonomous learning,which will help to improve the efficiency of web-based college English autonomous learning and achieve the revolution and innovation of college English.