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A Study On Iterative Learning control With Adjustment Of Learning Interval For Monotone Convergence In The Sense Of Sup-Norm

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Asian Journal of control 2008年第1期4卷

作者： Kwang-Hyun Park Zeungnam Bien Division of EE Department of EECS Korea Advanced Institute of Science and Technology 373–1 Kusong-dong Yusong-gu Taejon 305–701 Korea. Zeungname Bien:received the B.S. degree in electronics engineering from Seoul National University Seoul Korea in 1969 and the M.S. and Ph.D. degrees in electrical engineering from the University of Iowa Iowa City Iowa U.S.A. in 1972 and 1975 respectively. During 1976–1977 academic years he taught as assistant professor at the Department of Electrical Engineering University of Iowa. Then Dr. Bien joined Korea Advanced Institute of Science and Technology summer 1977 and is now Professor of Control Engineering at the Department of Electrical Engineering and Computer Science KAIST. Dr. Bien was the president of the Korea Fuzzy Logic and Intelligent Systems Society during 1990–1995 and also the general chair of IFSA World Congress 1993 and for FUZZ-IEEE99 respectively. He is currently co-Editor-in-Chief for International Journal of Fuzzy Systems (IJFS) Associate Editor for IEEE Transactions on Fuzzy Systems and a regional editor for the International Journal of Intelligent Automation and Soft Computing. He has been serving as Vice President for IFSA since 1997 and is now Chief Chairman of Institute of Electronics Engineers of Korea and Director of Humanfriendly Welfare Robot System Research Center. His current research interests include intelligent control methods with emphasis on fuzzy logic systems service robotics and rehabilitation engineering and large-scale industrial control systems. Kwang-Hyun Park:received the B.S. M.S. and Ph.D. degrees in electrical engineering and computer science from KAIST Korea in 1994 19997 and 2001 respectively. He is now a researcher at Human-friendly Welfare Robot System Research Center. His research interests include learning control machine learning human-friendly interfaces and service robotics.

It has been found that some huge overshoot in the sense of sup-norm may be observed when typical iterative learning control (ILC) algorithms are applied to LTI systems, even though monotone convergence in the sense of λ-norm is guaranteed. In this paper, a new ILC algorithm with adjustment of learning interval is proposed to resolve such an undesirable phenomenon, and it is shown that the output error can be monotonically converged to zero in the sense of sup-norm when the proposed ILC algorithm is applied. A numerical example is given to show the effectiveness of the proposed algorithm.

关键词： Iterative learning control monotone convergence learning interval sup-norm

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Methods for Balanced Charge Carriers and Enhanced Efficiency of Organic Phosphorescent Devices

Methods for Balanced Charge Carriers and Enhanced Efficiency...

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2007亚洲光电子会议LED材料与器件分会场

作者： Byung Doo Chin Nam Su Kang Heume-Il Baek Changhee Lee Material Science and Technology Division Korea Institute of Science & Technology School of Electrical Engineering and Computer Science and Inter-University Semiconductor Research Center Seoul National University

In this paper, the light emitting efficiency, spectrum, and the lifetime of the phosphorescent devices, whose emission characteristics are strongly dominated not only by the energy transfer but also by the charge carrier trapping induced by the emissive dopant, are explained by differences in the energy levels of the host, dopant, and nearby transport layers. On the basis of our finding on device performance and photocurrent measurement data by time-of-flight (TOF), we suggest a detailed emission mechanism, along with a physical interpretation and practical design scheme for improving the efficiency and lifetime of devices. Moreover, the effects of the modification of charge (both hole and electrons) transporting layers which results in a drop of operating voltage and improved efficiency on the performance of electrophosphorescent device are investigated experimentally. Using the Ir-based phosphorescent emitter, vacuum-evaporated, solution-processed, and composition of their hybrid structures are designed for better charge carrier balance and efficient exciton blocking behavior.

关键词： Balanced charge carrier, Mobility, Electrophosphorescence, Interfacial layer, Efficiency

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Post-treatment Effect on the electrical Properties of Triisopropylsilyl Pentacene Organic Thin-film Transistors

Post-treatment Effect on the Electrical Properties of Triiso...

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2007亚洲显示国际会议

作者： Yong-Hoon Kim Jae-Hoon Lee Min-Koo Han Jeong-In Han Information Display Research Center Korea Electronics Technology Institute Seongnam 463-816 School of Electrical Engineering and Computer Science Seoul National University Seoul 151-742 Korea School of Electrical Engineering and Computer Science Seoul National University Seoul 151-742 Korea School of Electrical Engineering and Computer Science Seoul National University Seoul 151-742 Korea Information Display Research Center Korea Electronics Technology Institute Seongnam 463-816

By employing a post-treatment in N atmosphere at room temperature,the electrical properties of ink-jet printed triiso- propylsilyl pentacene organic thin-film transistors（OTFTs）such as current on/off ratio and subthreshold slope were sig- nificantly *** current on/off ratio of the OTFT device increased from 10～4 to 10～5 after the post-treatment and the subthreshold slope was improved from 8.5 V/decade to 2 V/*** field-effect mobility of the device was not sig- nificantly affected by the *** have also employed a post-treatment in vacuum at room temperature and the off-current of OTFT devices decreased by 1 order after the treatment.

关键词： Organic Thin-film Transistor Triisopropylsilyl Pentacene Ink-jet Printing Post-treatment

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Forecasting Solar Activity Using Co-evolution of Models and Tests

Forecasting Solar Activity Using Co-evolution of Models and ...

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International Conference on Intelligent Systems Design and Applications (ISDA)

作者： M. Mirmomeni C. Lucas B. N. Araabi B. Moshiri Control and Intelligent Processing Center of Excellence School of Electrical and Computer Engineering University of Tehran Tehran Iran School of Cognitive Science Institute of Studies in Theoretical Physics and Mathematics Tehran Iran

The cyclic solar activity has significant effects on earth, climate, satellites and space missions. Several methods have been introduced for the prediction of sunspot number, which is a common measure of solar activity. In this study a co-evolutionary algorithm is presented for inferring the topology and parameters of a multilayered neural network with the minimum of experimentation to the sunspot number time series which will be used as a predictor in predicting such phenomena. The algorithm synthesizes an explicit model directly from the observed data produced by intelligently generated tests. The algorithm is composed of two co-evolving populations; one population evolves candidate neural networks. The second population evolves informative tests that either extract new information from the hidden system or elicit desirable behavior from it. The fitness of candidate neural networks is their ability to explain behavior of the target chaotic system observed in response to all tests carried out so far; the fitness of candidate tests is their ability to make the models disagree in their predictions. The generality of this modeling-evaluation algorithm is demonstrated by applying the chosen model of this algorithm to predict sunspot number and the results depict the power of this training method which yields proper model to predict such chaotic time series.

关键词： Predictive models Neural networks System testing Power system modeling Chaos Earth Satellites Space missions Network topology Multi-layer neural network

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A Hybrid control Strategy for Robust Contact Detection and Force Regulation

A Hybrid Control Strategy for Robust Contact Detection and F...

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American control Conference (ACC)

作者： Raffaella Carloni Ricardo G. Sanfelice Andrew R. Teel Claudio Melchiorri Center for Research on Complex Automated Systems (CASY) Department of Electronics Computer Science and Systems (DEIS) University of Bologna Bologna Italy Center for Control Engineering and Computation Electrical and Computer Engineering Department University of California Santa Barbara CA USA

We present an innovative hybrid control strategy for contact detection and force regulation of robotic manipulators. This hybrid architecture controls the robotic manipulator during the following stages of interaction with the work environment: the free motion, the transition phase, and the constrained motion. The proposed control strategy is to switch between a position and a force controller with hysteresis relying only on contact force measurements. We implement this strategy in a hybrid controller and provide a design procedure which depends on the viscoelastic parameters of the work environment. Our controller guarantees contact detection and force regulation without bounce-off effects between the robotic manipulator and the work environment from compact sets of initial conditions. Additionally, the resulting closed-loop system is robust to measurement noise. We include simulations that show how the proposed hybrid control strategy guarantees good performance in the cases of stiff and compliant work environments, and in the presence of measurement noise.

关键词： Force control Robust control Contacts Robots Manipulators Switches Force measurement Noise measurement Working environment noise Motion control

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TRACKING control IN THE PRESENCE OF NONLINEAR DYNAMIC FRICTIONAL EFFECTS: ROBOT EXTENSION

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Asian Journal of control 2008年第3期1卷

作者： M. Feemster D.M. Dawson A. Behal W. Dixon Matthew 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 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.

关键词： Friction compensation nonlinear control

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The Stability Analysis of the Adaptive Fading Extended Kalman Filter

The Stability Analysis of the Adaptive Fading Extended Kalma...

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IEEE Conference on control Technology and Applications (CCTA)

作者： Kwang Hoon Kim Jang Gyu Lee Chan Gook Park Gyu In Jee Department of Electronics Engineering Brain Korea 21 Research Group Konkuk University Seoul South Korea School of Electrical Engineering and Computer Science and Automatic Control Research Center Seoul National University Seoul South Korea School of Mechanical and Aerospace Engineering and Institute of Advanced Aerospace Technology Seoul National University Seoul South Korea Department of Electronics Engineering Konkuk University Seoul South Korea

The well-known conventional Kalman filter gives the optimal solution but requires an accurate system model and exact stochastic information. Thus, the Kalman filter with incomplete information may be degraded or even diverged. In a number of practical situations, the system model and the stochastic information are incomplete. To solve this problem, a new adaptive fading Kalman filter (AFKF) using the forgetting factor has recently been proposed. This paper extends the AFKF to nonlinear system models to obtain an adaptive fading extended Kalman filter (AFEKF). The forgetting factor is generated from the ratio between the calculated innovation covariance and the estimated innovation covariance. Based on the analysis result of Reif for the EKF, the stability of the AFEKF is also analyzed.

关键词： Stability analysis Fading Stochastic systems Nonlinear equations Nonlinear systems Information filtering Information filters Adaptive filters control systems Degradation

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Analyzing the Fuzzy ARTMAP Matchtracking mechanism with Co-Objective Optimization Theory

Analyzing the Fuzzy ARTMAP Matchtracking mechanism with Co-O...

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International Joint Conference on Neural Networks (IJCNN)

作者： Jose Castro Michael Georgiopoulos Jimmy Secretan Computing Research Center Costa Rica Institute of Technology USA School of Electrical Engineering and Computer Science University of Central Florida Orlando FL USA

In the process of learning a pattern I, the fuzzy ARTMAP algorithm templates (i.e., the weight vectors corresponding to nodes of its category representation layer) compete for the representation of the given pattern. This competition can induce matchtracking : a process that iterates a number of times over the template set searching for a template w* of the correct class that best represents the pattern I. In this paper, we analyze the search for a winning template from the perspective of bi-criterion optimization and prove that it is actually a walk along the Pareto front of an appropriately defined co-objective optimization problem. This observation allows us to propose the basis for an implementation variant of Fuzzy ARTMAP that (a) produces exactly the same network as Fuzzy ARTMAP, (b) avoids matchtracking by explicitly keeping track of a subset of the Pareto front, (c) finds the correct template to represent an input pattern through a single pass over the template set and (d) eliminates the need for the Fuzzy ARTMAP parameter ε.

关键词： Neural networks Fuzzy neural networks Fuzzy sets Pattern matching Pattern analysis Pareto optimization Pipelines Algorithm design and analysis Pareto analysis Detectors

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

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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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Filtering of discrete linear repetitive processes with ∞ and 2-∞ performance

Filtering of discrete linear repetitive processes with ∞ an...

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2007 IEEE International Symposium on Circuits and Systems, ISCAS 2007

作者： Ligang, Wu Lam, James Paszke, Wojciech Galkowski, Krzysztof Rogers, Eric Kummert, Anton Space Control and Inertial Technology Research Center Harbin Institute of Technology Harbin 150001 China Department of Mechanical Engineering University of Hong Kong Pokfulam Road Hong Kong Hong Kong Institute of Control and Computation Engineering University of Zielona Góra 65-246 Zielona Góra Poland School of Electronics and Computer Science University of Southampton Southampton SO17 IBJ United Kingdom University of Wuppertal Faculty of Electrical Information and Media Engineering Communication Theory

This paper considers the general filtering problem for a distinct class of two-dimensional (2-D) discrete linear systems, i.e. information propagation in two independent directions, known as discrete linear repetitive processes which are of both system-theoretic and applications interest. In particular, new results on the design of filters with guaranteed levels of performance are developed. These take the form of algorithms for the design of an ∞ and 2-∞ dynamic output feedback filter which guarantees that the resulting filtering error process is stable and has prescribed disturbance attenuation performance as measured by ∞ and 2- ∞ norms. © 2007 IEEE.

关键词： Signal filtering and prediction

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