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作者： Goebel, Rafal Prieur, Christophe Teel, Andrew R. Department of Mathematics University of Washington Seattle WA 98195-4350 United States LAAS-CNRS 7 Avenue du Colonel Roche 31077 Toulouse Cedex 4 France Center for Control Dynamical Systems and Computation Department of Electrical and Computer Engineering University of California Santa Barbara CA 93106-9560 United States

ISBN: (纸本)9783902661289

A smooth patchy control Lyapunov function for a nonlinear control system consists of an ordered family of smooth local control Lyapunov functions, whose open domains form a locally finite cover of the state space of the system, and which satisfy a certain arrangement property. In contrast to (Goebel et al., IEEE CDC, 2006), on each intersection of the domains, we do not impose a decrease condition of the local control Lyapunov functions when the index increases. We show a construction, based on such a patchy control Lyapunov function, of a stabilizing hybrid feedback that is robust to measurement noise. Copyright © 2007 IFAC.

关键词： Hybrid systems

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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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EEG Effects of Motion Sickness Induced in a Dynamic Virtual Reality Environment

EEG Effects of Motion Sickness Induced in a Dynamic Virtual ...

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29th Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBS 2007), vol.10

作者： Chin-Teng Lin Shang-Wen Chuang Yu-Chieh Chen Li-Wei Ko Sheng-Fu Liang Tzyy-Ping Jung Department of Electrical and Control Engineering the Department of Computer Science Brain Research Center Hsinchu Taiwan The Department of Computer Science Brain Research Center Hsinchu Taiwan Department of Electrical and Control Engineering Brain Research Center Hsinchu Taiwan Department of Computer Science and Information Engineering National Cheng Kung University Tainan Taiwan Institute for Neural Computation University of California San Diego CA USA

The Electroencephalogram (EEG) dynamics which relate to motion sickness are studied in this paper. Instead of providing visual or motion stimuli to the subjects to induce motion sickness, we employed a dynamic virtual-reality (VR) environment in our research. The environment consisted of a 3D surrounding VR scene and a motion platform providing a realistic situation. This environment provided the advantages of safety, low cost, and the realistic stimuli to induce motion sickness. The Motion Sickness Questionnaire (MSQ) was used to assess the sickness level, and the EEG effects on the subjects with high sickness levels were investigated using the independent component analysis (ICA). The fake-epoch extraction was then applied to the nausea-related independent components. Finally we employed the Event-Related Spectral Perturbation (ERSP) technology on the fake-epochs in order to determine the EEG dynamics during motion sickness. The experimental results show that most subjects experienced an 8-10Hz power increase to their motion sickness-related phenomena in the parietal and motor areas. Moreover, some subjects experienced an EEG power increase of 18-20Hz in their synchronized responses recorded in the same areas. The motion sickness-related effects and regions can be successfully obtained from our experimental results.

关键词： Electroencephalography Virtual reality Layout Vehicle dynamics computer science Safety Motion analysis Independent component analysis control engineering Costs

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Cooperative Graph-Based Model Predictive Search

Cooperative Graph-Based Model Predictive Search

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Proceedings of the 46th IEEE Conference on Decision and control, Pages 5971-6447

作者： James R. Riehl Gaemus E. Collins Joao P. Hespanha Center for Control Dynamical Systems and Computation Electrical and Computer Engineering Department University of California Santa Barbara CA USA Toyon Research Corporation Goleta CA USA

ISBN: (纸本)9781424414970;1424414970

We present a receding-horizon cooperative search algorithm that jointly optimizes routes and sensor orientations for a team of autonomous agents searching for a mobile target. By sampling the region of interest at locations with high target probability, we reduce the continuous search problem to an optimization on a finite graph. Paths are computed on this graph using a receding horizon approach, in which the horizon is a fixed number of waypoints. To facilitate a fair comparison between paths of varying length on a non-uniform graph, we use an optimization criterion corresponding to the probability of finding the target per unit time. Using this algorithm, we show that the team discovers the target in finite time with probability one. Simulations verify that this algorithm makes effective use of agents and performs significantly better than previously proposed search algorithms. We have also successfully tested this search algorithm on a physical system consisting of two UAVs with gimbal-mounted cameras.

关键词： SEARCHING ALGORITHM optimal criterion maneuvering target Horizon Intelligent agents Probability Line graph Targets algorithms region of interest Teams Paths continuous search Byways

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Using supervised fuzzy clustering and cwt for ventricular late potentials (vlps) detection in high-resolution ecg signal

Using supervised fuzzy clustering and cwt for ventricular la...

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5th Conference of the European Society for Fuzzy Logic and Technology, EUSFLAT 2007

作者： Khorshidi, Gholamreza Salimi Jaafari, Ayyoub Pourmorteza, Amir Motie, Ali Golpayegani, Mohammadreza Hashemi School of Cognitive Sciences Institute for Studies in Theoretical Physics and Mathematics Tehran Iran Faculty of Biomedical Engineering Amirkabir University of Technology Tehran Iran Iran Control and Intelligent Processing Center of Excellence Electrical and Computer Engineering Department University of Tehran Tehran Iran Nasrabadi Group of Biomedical Engineering Faculty of Engineering Shahed University Tehran Iran

ISBN: (纸本)9788073683863

Ventricular Late Potentials (VLPs) are lowamplitude, high-frequency components that appear at the end of the QRS complex of a High-Resolution ECG (HRECG) record. VLPs are clinically useful for identifying post-MI (Myocardial Infarction) patients prone to Ventricular Tachycardia (VT) and Sudden Cardiac Death (SCD). In this paper, the Continuous Wavelet Transform (CWT) and a supervised fuzzy clustering algorithm are used together to detect VLP. The terminal part of the QRS complex in the Vector Magnitude (VM) waveform is processed with the CWT to extract a feature vector. Resulting time-frequency representation is subdivided into several sub bands, and the sum of the squared decomposition coefficients is computed in each region. Finally, a supervised Fuzzy clustering method, trained by an appropriate set of these feature vectors, is applied to this data in order to identify VLP.

关键词： Electrocardiograms

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Basic Movements of a Nonholonomic Wheel-Based Pole Climbing Robot

Basic Movements of a Nonholonomic Wheel-Based Pole Climbing ...

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2007 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, Pages 805-1210

作者： Sara Mahdavi Ehsan Noohi Majid Nili Ahmadabadi Control and Intelligent Processing Center of Excellence Department of Electrical and Computer Engineering University of Tehran

ISBN: (纸本)9781424412631;1424412633

Three basic movements for path planning of a nonholonomic wheel-based pole climbing robot, UT-PCR, are proposed. In order to simplify the system equations, the state equations are first derived in the velocity space in which the nonholonomic constraint is easily shown. Subsequently, according to the derived equations, three basic movements are defined and a suitable control method is proposed. Finally, the proposed movements and the control method are tested via simulations.

关键词： Climbing Robot Nonholonomic Systems Basic Movements

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OBSERVER-BASED STABILIZATION OF SYSTEMS WITH MONOTONIC NONLINEARITIES

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Asian Journal of control 2008年第1期1卷

作者： Murat Arcak Petar Kokotović Center for Control Engineering and Computation University of Calitornia Santa Barbara CA 93106-9560 U.S.A. Petar V. Kokotovic has been active for more than thirty years as control engineer researcher and educator first in his native Yugoslavia and then from 1966 through 1990 at the University of Illinois where he held the endowed Grainger Chair. In 1991 he joined the University of California Santa Barbara where he directs the Center for Control Engineering and Computation. He has co-authored eight books and numerous articles contributing to sensitivity analysis singular perturbation methods and robust adaptive and nonlinear control. Professor Kokotovic is also active in industrial applications of control theory. As a consultant to Ford he was involved in the development of the first series of automotive computer controls and at General Electric he participated in large scale systems studies. Professor Kokotovic is a Fellow of IEEE and a member of National Academy of Engineering. He received the 1983 and 1993 outstanding IEEE Transactions Paper Awards and presented the 1991 Bode Prize Lecture. He is the recipient of the 1990 IFAC Quazza Medal and the 1995 IEEE Control Systems Award.

We design an observer-based control law for a class of systems that include monotonic nonlinearities of the unmeasured states. Our observer results in nonlinear error dynamics which can be represented as the feedback interconnection of a linear system and a time-verying multivariable sector nonlinearity. The convergence of the estimation error is guaranteed by an observer matrix that renders the linear part passive, and is computable with LMI software. The feedback design is completed by combining the observer with a control law that renders the plant input-to-state stable with respect to the state estimation error.

关键词： Output feedback nonlinear observers backstepping

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UNITING LOCAL AND GLOBAL OUTPUT FEEDBACK controlLERS

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IFAC Proceedings Volumes 2007年第12期40卷 492-497页

作者： Christophe Prieur Andrew R. Teel LAAS–CNRS 7 Avenue du Colonel Roche 31077 Toulouse Cedex 4 France Center for Control Dynamical Systems & Computation Department of Electrical and Computer Engineering University of California Santa Barbara CA 93106-9560

We consider control systems for which we know two stabilizing output feedback controllers. One is globally asymptotically stabilizing, while the other one is only locally asymptotically stabilizing. We look for a composite output feedback control law that is equal to the local feedback on a neighborhood of the origin and that is globally asymptotically stabilizing. We insist on using only output feedback controllers to solve this uniting problem. Since we want some robustness with respect to measurement noise, actuator errors and external disturbances, we consider hybrid output feedback controllers, following recent developments in the literature on robustness in hybrid systems. Under an input-output-to-state stability assumption, we exhibit a solution of this uniting problem by means of a dynamic hybrid output feedback controller.

关键词： hybrid systems global stabilization local performance output feedback robustness

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Subtleties in Robust Stability of Discrete-time Piecewise Affine Systems

Subtleties in Robust Stability of Discrete-time Piecewise Af...

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American control Conference (ACC)

作者： M. Lazar W.P.M.H. Heemels A.R. Teel University of California Santa Barbara Santa Barbara CA US Department of Mechanical Engineering Eindhovan University of Technology Eindhoven Netherlands Center for Control Engineering and Computation Department of Electrical and Computer Engineering University of California Santa Barbara USA

In this paper we consider (inherent) robustness of discrete-time piecewise affine (PWA) systems. We demonstrate, via examples, that globally exponentially stable discrete-time PWA systems may have no robustness. More precisely, we show that the exponential stability property cannot prevent that arbitrarily small additive disturbances keep the state trajectory far from the origin. Mathematically speaking, this means that the system is not input-to-state stable with respect to arbitrarily small disturbances. The non-robustness property is related to the absence of a continuous Lyapunov function. These results indicate that one should be careful with existing stability analysis and synthesis methods for PWA systems that rely on discontinuous Lyapunov functions, as no robustness might be present. However, as the search for Lyapunov functions for discrete-time PWA systems often employs discontinuous Lyapunov functions (e.g. piecewise quadratic ones), robustness tests based on discontinuous Lyapunov functions are needed. Such tests are proposed in this article.

关键词： Robust stability Lyapunov method Robustness Asymptotic stability control system synthesis control systems Additives Stability analysis System testing Biological system modeling

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Power management by brain emotional learning algorithm

Power management by brain emotional learning algorithm

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International Conference on ASIC

作者： Mehrzad Samadi Ali Afzali-Kusha Caro Lucas Nanoelectronics Center of Exellence School of Electrical and Computer Engineering University of Tehran Tehran Iran Control and Intelligent Processing Center of Excellence Department of Electrical and Computer Engineering University of Tehran Tehran Iran

Nowadays having the most energy efficiency is desirable in its own right from both economical and environmental points of view. Dynamic power management is a system level solution for reducing the consumed energy with putting off unused parts of the system and putting them on in an efficient time. The Emotional Learning Algorithm has been introduced to show the effect of emotions as well known stimuli in the quick and almost satisfying decision making in human. The remarkable properties of emotional learning, low computational complexity and fast training, and its simplicity in multi objective problems has made it a powerful methodology in real time control and decision systems, where the gradient based methods and evolutionary algorithms are hard to be used due to their high computational complexity. Recently the emotional approach has been successfully used to obtain multiple objectives in prediction problems of real world phenomena. At first we introduce methods of dynamic power management and then a new method based on BELBIC would be explained. The simulation results show that this method has a high efficiency in various systems.

关键词： Energy management Power system management computational complexity Energy efficiency Power system economics Power generation economics Economic forecasting Environmental economics Decision making Humans

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