We present results of a collaboration project, during which parts of General Motors' north American vehicle supply chain have been modeled and evaluated. A variant of colored stochastic Petri nets has been develop...
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We present results of a collaboration project, during which parts of General Motors' north American vehicle supply chain have been modeled and evaluated. A variant of colored stochastic Petri nets has been developed for this task, and support for model creation and performance evaluation was implemented in our tool timeNET. Variations of the model and their stepwise evaluation lead to suggestions about how the supply chain can be reorganized in order to improve the time between customer order and vehicle delivery (order-to-delivery time).
An approach and method to integrate virtual engineering and robot systems is introduced. The main idea is extended application of the principle of shape aspect that is well-proven in part modeling. Shape intensive rob...
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An approach and method to integrate virtual engineering and robot systems is introduced. The main idea is extended application of the principle of shape aspect that is well-proven in part modeling. Shape intensive robot system is engineered by using of shape modeling. Shapes are connected by special aspects in a shape aspect oriented model system. The main purpose of the proposed approach and method is better communication between product modeling and robot related engineering. Associativity definitions integrate part level functions into product level functions while behaviors and adaptivities are also handled as aspects. Paper starts with introduction and comparison of classical industrial product modeling and the proposed integrated product and robot system modeling. Following this, extended application of shape aspects and definition of connective aspects are detailed. Finally, implementation in open architecture industrial modeling systems is explained and future work is outlined.
作者：
M. FeemsterD.M. DawsonA. BehalW. DixonMatthew Feemster received the B.S degree in Electrical Engineering from Clemson University
Clemson South Carolina in December 1994. Upon graduation he remained at Clemson University and received the M.S. degree in Electrical Engineering in 1997. During this time he also served as a research/teaching assistant. His research work focused on the design and implementation of various nonlinear control algorithms with emphasis on the induction motor and mechanical systems with friction present. He is currently working toward his Ph.D. degree in Electrical Engineering at Clemson University. Darren M. Dawson was born in 1962
in Macon Georgia. He received an Associate Degree in Mathematics from Macon Junior College in 1982 and a B.S. Degree in Electrical Engineering from the Georgia Institute of Technology in 1984. He then worked for Westinghouse as a control engineer from 1985 to 1987. In 1987 he returned to the Georgia Institute of Technology where he received the Ph.D. Degree in Electrical Engineering in March 1990. During this time he also served as a research/teaching assistant. In July 1990 he joined the Electrical and Computer Engineering Department and the Center for Advanced Manufacturing (CAM) at Clemson University where he currently holds the position of Professor. Under the CAM director's supervision he currently leads the Robotics and Manufacturing Automation Laboratory which is jointly operated by the Electrical and Mechanical Engineering departments. His main research interests are in the fields of nonlinear based robust adaptive and learning control with application to electro-mechanical systems including robot manipulators motor drives magnetic bearings flexible cables flexible beams and high-speed transport systems. Aman Behal was born in India in 1973. He received his Masters Degree in Electrical Engineering from Indian Institute of Technology
Bombay in 1996. He is currently working towards a Ph.D in Controls and Robotics at Clemson University. His research focuses on the control of no
In this paper, we extend the observer/control strategies previously published in [25] to an n -link, serially connected, direct drive, rigid link, revolute robot operating in the presence of nonlinear friction effects...
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In this paper, we extend the observer/control strategies previously published in [25] to an n -link, serially connected, direct drive, rigid link, revolute robot operating in the presence of nonlinear friction effects modeled by the Lu-Gre model. In addition, we also present a new adaptive control technique for compensating for the nonlinear parameterizable Stribeck effects. Specifically, an adaptive observer/controller scheme is developed which contains a feedforward approximation of the Stribeck effects. This feedforward approximation is used in a composite controller/observer strategy which forces the average square integral of the position tracking error to an arbitrarily small value. Experimental results are included to illustrate the performance of the proposed controllers.
作者：
Omid ShakerniaYi MaT. John KooShankar SastryDept. 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-mot...
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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.
A mathematical model and control for autonomous small size helicopters were analyzed, which were equipped with different sensors, and can be used in many practical applications. Based on the derived model, a control f...
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A mathematical model and control for autonomous small size helicopters were analyzed, which were equipped with different sensors, and can be used in many practical applications. Based on the derived model, a control for the basic helicopter and one for the helicopter with heavy or bulky load rigidly attached to the fuselage are designed and tested in laboratory flight experiments. The main rotor was modeled as a separate rigid body as a result of the contribution estimation. The demonstration of good match between model and flight experiment dynamics were analyzed. A controller was designed, and its good performance was demonstrated by using the derived model.
3D environment reconstruction is a basic task, delivering the data for mapping, localization and navigation in mobile robotics. We present a new technique that combines a stereo-camera system with a PMD-camera. Both s...
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3D environment reconstruction is a basic task, delivering the data for mapping, localization and navigation in mobile robotics. We present a new technique that combines a stereo-camera system with a PMD-camera. Both systems generate distance images of the environment but with different characteristics. It is shown that each system compensates effectively for the deficiencies of the other one. The combined system is real-time suited. Experimental data of an indoor scene including the calibration procedure are reported
The outdoor service robot, which we call OSR-02, is presently under development intended for cleaning up urban areas by means of collecting discarded trash such as plastic bottles, cans, plastic bags and so on. Additi...
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The outdoor service robot, which we call OSR-02, is presently under development intended for cleaning up urban areas by means of collecting discarded trash such as plastic bottles, cans, plastic bags and so on. Additionally, we have developed a novel sensor system for the achievement of the task by this robot; it is constructed with LRF (laser rangefinder), two cameras, and three stepping motors. In this paper, we describe the sensor system and its applications
The synchronous language Esterel is an established language for developing reactive systems. It gives an abstract, well-defined and executable description of the application, and can be synthesized into hardware and s...
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MARVIN is a model-helicopter based flying robot, which is able to operate completely autonomously. It has been designed to fulfill the demands of the International Aerial robotics Competition (IARC) Millennial Event 1...
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This paper presents a distributed, master-less communication system currently used for communication in a fleet of heterogeneous unmanned aerial vehicles in the European project COMETS for wired and wireless links. Co...
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