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LANDING AN UNMANNED AIR VEHICLE: VISION BASED MOTION ESTIMATION AND NONLINEAR CONTROL

Asian Journal of Control 2008年第3期1卷

作者： Omid Shakernia Yi Ma T. John Koo Shankar Sastry Dept. of Electrical Engineering & Computer Science University of California at Berkeley Berkeley CA94720-1774 U.S.A. Tak-Kuen John Koo received the B.Eng. degree in 1992 in Electronic Engineering and the M.Phil. in 1994 in Information Engineering both from the Chinese University of Hong Kong. From 1994 to 1995 he was a graduate student in Signal and Image Processing Institute at the University of Southern California. He is currently a Ph.D. Candidate in Electrical Engineering and Computer Sciences at the University of California at Berkeley. His research interests include nonlinear control theory hybrid systems inertial navigation systems with applications to unmanned aerial vehicles. He received the Distinguished M.Phil. Thesis Award of the Faculty of Engineering The Chinese University of Hong Kong in 1994. He was a consultant of SRI International in 1998. Currently he is the team leader of the Berkeley AeRobot Team and a delegate of The Graduate Assembly University of California at Berkeley. He is a student member of IEEE and SIAM. S. Shankar Sastry received his Ph.D. degree in 1981 from the University of California Berkeley. He was on the faculty of MIT from 1980-82 and Harvard University as a Gordon McKay professor in 1994. He is currently a Professor of Electrical Engineering and Computer Sciences and Bioengineering and Director of the Electronics Research Laboratory at Berkeley. He has held visiting appointments at the Australian National University Canberra the University of Rome Scuola Normale and University of Pisa the CNRS laboratory LAAS in Toulouse (poste rouge) and as a Vinton Hayes Visiting fellow at the Center for Intelligent Control Systems at MIT. His areas of research are nonlinear and adaptive control robotic telesurgery control of hybrid systems and biological motor control. He is a coauthor (with M. Bodson) of “Adaptive Control: Stability Convergence and Robustness Prentice Hall 1989.” and (with R. Murray and Z. Li) of “A Mathematical Introduction to Robotic Manipulati

In this paper, we use computer vision as a feedback sensor in a control loop for landing an unmanned air vehicle (UAV) on a landing pad. The vision problem we address here is then a special case of the classic ego-motion estimation problem since all feature points lie on a planar surface (the landing pad). We study together the discrete and differential versions of the ego-motion estimation, in order to obtain both position and velocity of the UAV relative to the landing pad. After briefly reviewing existing algorithm for the discrete case, we present, in a unified geometric framework, a new estimation scheme for solving the differential case. We further show how the obtained algorithms enable the vision sensor to be placed in the feedback loop as a state observer for landing control. These algorithms are linear, numerically robust, and computationally inexpensive hence suitable for real-time implementation. We present a thorough performance evaluation of the motion estimation algorithms under varying levels of image measurement noise, altitudes of the camera above the landing pad, and different camera motions relative to the landing pad. A landing controller is then designed for a full dynamic model of the UAV. Using geometric nonlinear control theory, the dynamics of the UAV are decoupled into an inner system and outer system. The proposed control scheme is then based on the differential flatness of the outer system. For the overall closed-loop system, conditions are provided under which exponential stability can be guaranteed. In the closed-loop system, the controller is tightly coupled with the vision based state estimation and the only auxiliary sensor are accelerometers for measuring acceleration of the UAV. Finally, we show through simulation results that the designed vision-in-the-loop controller generates stable landing maneuvers even for large levels of image measurement noise. Experiments on a real UAV will be presented in future work.

关键词： Motion estimation computer vision based control unmanned air vehicle differential flatness

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Advances in Telerobotics 1

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丛书名： Springer Tracts in Advanced robotics

2007年

作者： Manuel Ferre Rafael Aracil Martin Buss Claudio Melchiorri Carlos Balaguer

ISBN: (数字)9783540713647

ISBN: (纸本)9783540713630;9783642425929

At the dawn of the new millennium, robotics is undergoing a major transformation in scope and dimension. From a largely dominant industrial focus, robotics is rapidly expanding into the challenges of unstructured environments. Interacting with, assi- ing, serving, and exploring with humans, the emerging robots will increasingly touch people and their lives. The goal of the new series of Springer Tracts in Advanced robotics (STAR) is to bring, in a timely fashion, the latest advances and developments in robotics on the basis of their signi cance and quality. It is our hope that the wider dissemination of research developments stimulates exchanges and collaborations among the research community and contributes to further advancement of this rapidly growing eld. The edited volume by Manuel Ferre, Martin Buss, Rafael Aracil, Claudio M- chiorri and Carlos Balaguer is focused on the most recent advances in telerobotics, a technology that deals with the inclusion of a human operator in the control loop of a remote robot. Telerobotics encompasses an area at the crossroads of several scienti c disciplines such as mechatronics, control, communication, computers, sensor-based recognition, multimodality and even teleoperation through Internet.

关键词： Control, robotics, Mechatronics Artificial Intelligence systems Theory, Control

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Autonomous large parafoil guidance, navigation, and control system design status

Autonomous large parafoil guidance, navigation, and control ...

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19th AIAA Aerodynamic Decelerator systems Technology Conference and Seminar

作者： Carter, David W. George, Sean Hattis, Philip D. Mcconley, Marc W. Rasmussen, Scott A. Singh, Leena Tavan, Steve Draper Laboratory Cambridge MA 02459 United States Natick Soldier Research Development and Engineering Center Natick MA 01760 United States Decision Systems Group Mail Stop 77 555 Technology Square United States Vehicle and Robotic Systems Group Mail Stop 23 555 Technology Square United States AIAA United States Mission Design and Analysis Group Mail Stop 70 555 Technology Square United States Tactics Guidance and Control Group Mail Stop 77 555 Technolog Square Cognitive Robotics Group Mail Stop 77 555 Technology Square Guidance and Control Group Mail Stop 77 555 Technology Square NSRDEC Warfighter Protection and Aerial Delivery Directorate AMSRD-NSC-WP-AJ Kansas Street United States

ISBN: (纸本)1563478943

Demonstration of autonomous Guidance, Navigation, and Control (GN&C) that can take parafoil airdrop systems from 25,000 feet to accurate landings is a key goal of the Joint Precision Airdrop System. A first instantiation test-flew a 10,000 pound-class parafoil system and has since been extended to accommodate payloads up to 30,000 pounds and as small as a few hundred pounds. The initial avionics applied by the GN&C software used a two-antenna Global Positioning System (GPS) receiver to obtain position, velocity, and heading data. Upgraded avionics now use a single-antenna GPS receiver providing position and velocity combined with inertial sensors providing three-axis acceleration and angular rate data. The guidance algorithm is partitioned into homing, energy management, and an optimized table-lookup terminal flight phase. The control algorithm is a proportional, integral, derivative design with features to deal with system constraints and with feed forward to improve response time. The GN&C software integration and testing is accomplished using a 6 degree-of-freedom simulation with both software-only and hardware-in-the-loop forms. GN&C with the original avionics enabled the 10,000 poundclass parafoil to achieve an expected delivery accuracy of about 150 meters. The GN&C using the new avionics is generalized for on-going tests with payloads ranging from 300 to 30,000 pounds.

关键词： Airfoils

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ANALYSIS OF TIPOVER STABILITY FOR NOVEL SHAPE SHIFTING MODULAR ROBOT

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Chinese Journal of Mechanical engineering 2006年第2期19卷 181-186页

作者： LIU Jinguo WANG Yuechao MA Shugen LI Bin Robotics Laboratory Shenyang Institute of Automation Chinese Academy of SciencesShenyang 110016 China Department of Systems Engineering Ibaraki UniversityIbaraki 316-8511 Japan Robotics Laboratory Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016 China

A novel three-module robot has been introduced. It can change its configuration to adapt to the uneven terrain and to improve its tipover stability. This three-module tracked robot has three kinds of symmetry configuration. They are line type, triangle type, and row type. After the factors and the countermeasures of mobile robot＇s tipover problem are analyzed, stability pyramid and tipover stabil-ity index are proposed to globally determinate the mobile robot＇s static stability and dynamic stability. The shape shifting robot is tested by this technique under the combined disturbance of pitch, roll and yaw in simulation. The simulation result shows that this technique is effective for the analysis of mobile robot＇s tipover stability, especially for the reconfigurable or shape shifting modular robot. Experiments on three symmetry configurations are made under unstructured environments. The environment experiment shows the same result as that of the simulation that the triangle type configuration has the best stability. Both simulation and experiment provide a valid reference for the reconfigurable robot＇s potential application.

关键词： Reconfigurable modular robot Shape shifting robot Stability pyramid Tipover stability index Unstructured environment

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MORPHbots: Lightweight modular self-reconfigurable robotics for space assembly, inspection, and servicing

MORPHbots: Lightweight modular self-reconfigurable robotics ...

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Space 2006 Conference

作者： Akin, David L. Roberts, Brian Roderick, Stephen Smith, Walter Henriette, Jean-Marc Space Systems Laboratory University of Maryland College Park MD 20742 Space Systems Laboratory Institute for Dexterous Space Robotics Department of Aerospace Engineering AIAA

ISBN: (纸本)1563478242

Under support from the Defense Advanced Research Projects Agency, the University of Maryland Space systems laboratory has been developing advanced miniaturized robotics for dexterous space operations. The final robotic architecture, now in prototype form, is a highly modular system capable of self-reconfiguration. These "MORPHbots" are composed of standardized actuator, sensor, and computational modules, interconnected by androgynous interface mechanisms capable of being actuated by the robots themselves. In a microsatellite configuration, a six degree-of-freedom serial manipulator with interchangeable end effectors has a total mass of only 10 kg, but is capable of performing assembly and servicing work typically performed by astronauts in pressure suits. Due to the modular nature of the system, a failed component can be easily removed and replaced with another unit, or the entire kinematics of the arm can be changed to better perform a given task In a "depot" situation, a collection of MORPHbot components stocked on an orbital platform can be used to assemble a wide variety of robotic systems, optimized for specific operational requirements, such as structural assembly or satellite servicing. This paper presents the MORPHbot concept in detail, along with samples of MORPHbot configurations for specific missions such as a robotic servicer for International Space Station and a low-mass orbital assembly system for exploration vehicles or large aperture science platforms. Results of performance and environmental testing on prototype MORPHbot actuator modules will be given, along with plans for near-term ground-based tests of the concept in end-to-end high fidelity simulations. Copyright © 2006 by University of Maryland Space systems laboratory.

关键词： robotics

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Human/robotic systems to enable in-space operations in the CEV era

Human/robotic systems to enable in-space operations in the C...

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Space 2006 Conference

作者： Akin, David L. Space Systems Laboratory University of Maryland College Park MD 20742 Space Systems Laboratory Institute for Dexterous Space Robotics Department of Aerospace Engineering AIAA

ISBN: (纸本)1563478242

This paper reviews technologies in extravehicular activity and space robotics that are applicable to routine operational use in conjunction with the crew exploration vehicle (CEV), and proposes several possible approaches to enable complex orbital operations on dedicated CEV missions. Preliminary designs and performance assessments are presented for two "servicing modules" to enable CEV servicing. The first design includes an external airlock with EVA suits for two crew members, robotics for grappling the target spacecraft and for dexterous servicing support for the EVA crew, and accommodations for orbital replacement units and other supplies needed for servicing. As an example, details are presented for how this unit would be used to allow the CEV to perform all activities currently planned for the upcoming SM-4 shuttle servicing mission for Hubble Space Telescope. The second design concept provides "stand-off" servicing for CEV through the use of free-flying servicing vehicles providing shirtsleeve environments for the single operators. These Space Construction and Orbital Utility Transport (SCOUT) modules were previously designed at the University of Maryland, and have been studied for design refinement and performance assessments in both analytical and experimental research at the Space systems laboratory. These systems would provide enhanced safety for the EVA crew, even in high-radiation environments such as geostationary orbit. Either system could be launched in a lengthened interstage structure between the CEV and the upper stage, and accessed via a transposition and docking maneuver identical to that used to extract the lunar module from the SFV-B stage in Apollo. Alternately, the servicing module could be launched separately on a non-human rated launch vehicle, and picked up by the CEV prior to maneuvering to reach the target spacecraft for servicing. Copyright © 2006 by University of Maryland Space systems laboratory.

关键词： Man machine systems

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Mobile scanning system for the fast digitization of existing roadways and structures

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Sensor Review 2006年第4期26卷 283-289页

作者： Grinstead, Brad Sukumar, Sreenivas Page, David Koschan, Andreas Gorsich, David Abidi, Mongi A. Imaging Robotics and Intelligent Systems Laboratory Department of Electrical and Computer Engineering University of Tennessee Knoxville TN United States US Army RDECOM Tank-Automotive Research Development and Engineering Center Warren MI United States

Purpose - To present a Mobile Scanning System for digitizing three-dimensional (3D) models of real-world terrain. Design/methodology/approach - A combination of sensors (video, laser range, positioning, orientation) is placed on a mobile platform, which moves past the scene to be digitized. Data fusion from the sensors is performed to construct an accurate 3D model of the target environment. Findings - The developed system can acquire accurate models of real-world environments in real time, at resolutions suitable for a variety of tasks. Originality/value - Treating the individual subsystems of the mobile scanning system independently yields a robust system that can be easily reconfigured on the fly for a variety of scanning scenarios. © Emerald Group Publishing Limited.

关键词： Analog to digital conversion

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Design and control of a four steered wheeled mobile robot

Design and control of a four steered wheeled mobile robot

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IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics

作者： Lauria, Michel Nadeau, Isabelle Lepage, Pierre Morin, Yan Giguère, Patrick Gagnon, Fréderic Létourneau, Dominic Michaud, François Department of Electrical Engineering and Computer Engineering Research Laboratory on Mobile Robotics and Intelligent Systems Université de Sherbrooke Sherbrooke QC J1K 2R1 Canada

ISBN: (纸本)1424401364

This paper presents the kinematical analysis of AZIMUT-2, a four steered wheeled mobile robot. The utilization of a new wheel concept called the AZIMUT wheel allowed us to create an innovative omnidirectional non-holonomic robot. Novelty of this wheel concept resides in the non-conventional positioning of the steering axis and the wheel axis. We propose a kinematical model based on the geometrical constraints of these wheels. The degree of mobility, steerability and maneuverability are studied. Additionally, we describe a special design implementation of the wheel mechanism to overcome a hypermotorization issue inherent to the wheel's geometrical properties. Finally, we describe AZIMUT-2's two operational and seven locomotion modes, along with a control algorithm based on the kinematical model of the robot. © 2006 IEEE.

关键词： Wheels

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Teaching robot design: Student-driven, open-ended design projects

Teaching robot design: Student-driven, open-ended design pro...

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113th Annual ASEE Conference and Exposition, 2006

作者： Bishop, Bradley Wick, Carl Piper, George U.S. Naval Academy United States United States Mobile Robotics Laboratory USNA Department of Systems Engineering United States Naval Academy United States

In this paper, we describe an open-ended robot design exercise that focuses on the design process. Students are tasked with defining a set of objectives, developing a solution strategy and constructing a final system. Students undertaking this exercise are working toward a metric based on sound engineering design, in contrast to the victory-based metrics typically associated (in the students' minds) with robotics competitions. The proposed format allows students a truly open-ended experience, since they must develop problem specifications themselves. Instructor support is required to assist in the development of an appropriate problem as well as during the design phase, but a well-prepared instructor can look forward to an extremely beneficial exercise that strongly motivates students and provides substantial dividends for the students in regards to robotics and engineering design in general. © American Society for engineering Education, 2006.

关键词： Intelligent robots

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A behavior-based architecture for realistic autonomous ship control

A behavior-based architecture for realistic autonomous ship ...

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2006 IEEE Symposium on Computational Intelligence and Games, CIG'06

作者： Olenderski, Adam Nicolescu, Monica Louis, Sushil J. Robotics Research Laboratory Dept. of Computer Science and Engineering University of Nevada Reno United States Evolutionary Computing Systems Lab Dept. of Computer Science and Engineering University of Nevada Reno United States

ISBN: (纸本)1424404649

Game environments provide a good domain for serious simulations such as those used in training Navy conning officers. Currently, a typical training scenario requires multiple personnel to play each of the boats and thus is expensive. We propose an approach to addressing this issue by developing intelligent, autonomous controllers for each boat. Significant challenges toward achieving these goals are the realism of behavior exhibited by the automated boats and their real-time response to change. In this paper we describe a control architecture that enables the real-time response of boats and the repertoire of realistic behaviors we developed for this application. We demonstrate the capabilities of our system with experimental results.

关键词： Personnel training

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