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COMPLEXITY ANALYSIS OF NETWORK-BASED DYNAMICAL systems

Journal of systems Science & Complexity 2011年第3期24卷 413-432页

作者： Guofeng ZHANG Long WANG Tongwen CHEN School of Electronic Engineering University of Electronic Science and Technology of China Chengdu 610054 China. Intelligent Control Laboratory Center for Systems and Control College of Engineering Peking University Beijing 100871 China Department of Electrical and Computer Engineering University of Alberta Edmonton Alberta T6G 2V4 Canada

This paper investigates the nonlinear dynamics of network-based dynamical systems where network communication channels of finite data rates are inserted into the closed loops of the control systems. The authors analyze the bifurcation and chaotic behavior of the non-smooth dynamical systems. The authors first prove that for almost all system parameters there are no periodic orbits. This result distinguishes this type of non-smooth dynamical systems from many others exhibiting border-collision bifurcations. Next, the authors show analytically that the chaotic sets are separated from the region containing the line segment of all fixed points with a finite distance. Finally, the authors employ a simple model to highlight that both the number of clients sharing a common network channel and fluctuations in the available network bandwidth have significant influence on the performance of such dynamical systems.

关键词： Bifurcation feedback network-based dynamical system non-convexity periodicity.

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H2 performance bounds for voltage regulation on a spatially-invariant DC power grid

H2 performance bounds for voltage regulation on a spatially-...

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作者： Rinehart, Michael Roozbehani, Mardavij Dahleh, Munther A. Laboratory for Information and Decision Systems Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA United States

ISBN: (纸本)9781457700804

Despite the importance of voltage regulation to operational reliability and safety of power grids, little is understood about how the topology of the physical layer, and the architecture of the communication and control layer impact the ability of the system to regulate the voltages. In this paper, we apply spatial-invariance analysis to develop analytical upper and lower bounds for the H2 gain of a DC power grid with respect to voltage regulation. These bounds establish a relation between network architecture and performance, and reveal fundamental limits to performance that cannot be overcome using feedback control. © 2011 AACC American Automatic control Council.

关键词： Electric power transmission networks

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Comparison Study between a Simple Sensorless Method and Adaptive Observer for DTC-SVM Five-Phase Induction Motor Drive

Comparison Study between a Simple Sensorless Method and Adap...

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IEEE Interantional Conference on Industrial Technology

作者： B. S. Khaldi H. Abu-Rub A. Iqbal R. Kennel M. O. Mahmoudi D. Boukhetala Department of Electrical Engineering Faculty of Science and Engineering Djelfa University Algeria Department of Electrical & Computer Engineering Texas A&M University at Qatar Doha Qatar Department of Electrical Engineering College of Engineering Qatar University Qatar Institute for Electrical Drive Systems and Power Electronics Technische Universitat Munchen Munich Germany Laboratory of Process Control National Polytechnic School Algiers Algeria

ISBN: (纸本)9781467303408;9781467303422

This paper highlights the differences between a simple sensorless method and an adaptive flux and speed observer for a five-phase induction motor control. The drive is controlled using space vector modulation direct torque control (DTC- SVM) approach. The power measurement used for speed computation is simple, with a minimum processor time and memory, and relatively robust against parameters variation when compared with the adaptive observer based approach. Simulation verification and real time implementation are presented in the paper.

关键词： direct torque control (DTC) space vector modulation (SVM) Five-phase induction machine speed sensorless power measurement adaptive observer

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High-dimensional Gaussian graphical model selection: walk summability and local separation criterion

The Journal of Machine Learning Research

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The Journal of Machine Learning Research 2012年第1期13卷

作者： Animashree Anandkumar Vincent Y. F. Tan Furong Huang Alan S. Willsky Electrical Engineering and Computer Science University of California Irvine Irvine CA Data Mining Department Institute for Infocomm Research Singapore Electrical and Computer Engineering National University of Singapore Stochastic Systems Group Laboratory for Information and Decision Systems Massachusetts Institute of Technology Cambridge MA

We consider the problem of high-dimensional Gaussian graphical model selection. We identify a set of graphs for which an efficient estimation algorithm exists, and this algorithm is based on thresholding of empirical conditional covariances. Under a set of transparent conditions, we establish structural consistency (or sparsistency) for the proposed algorithm, when the number of samples n = Ω(Jmin-2 log p), where p is the number of variables and Jmin is the minimum (absolute) edge potential of the graphical model. The sufficient conditions for sparsistency are based on the notion of walk-summability of the model and the presence of sparse local vertex separators in the underlying graph. We also derive novel non-asymptotic necessary conditions on the number of samples required for sparsistency.

关键词： Gaussian graphical model selection high-dimensional learning local-separation property necessary conditions for model selection walk-summability

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Continuous control of blood glucose in TIDM using fuzzy logic controller in insulin pump: A simulation study

Continuous control of blood glucose in TIDM using fuzzy logi...

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2011 2nd International Conference on control, Instrumentation and Automation, ICCIA 2011

作者： Maleki, Ali Geramipour, Arezou Semnan University Electrical and Computer Engineering Faculty Biomedical Engineering Department Iran Amirkabir University of Technology Biomedical Engineering Faculty Biological Systems Control Laboratory Iran

ISBN: (纸本)9781467316903

This paper presents a closed-loop control system for regulating blood glucose level in type-1 diabetic patients. The goals of designing controller are 1. avoidance of hypoglycemia (blood glucose concentrations should be above 3mmol/l) and 2. reduction in the blood glucose level (average blood glucose should be less than 7mmol/l) in diabetic patients. An intensive therapy for these patients is described by a continuous subcutaneous insulin infusion pump which mimics the natural insulin secretion in healthy person. The control algorithm uses experience of physicians to treat this disease by using Mamdani-type fuzzy logic controller (FLC). Robustness of this controller is tested by a group of diabetic patients models. Then to assess the performance and capabilities of fuzzy controller, the results of FLC were compared to PID controller for each diabetic patient. The results showed that FLC has a more stable response in presence of uncertainty in system parameters which can vary from patient to patient. © 2011 IEEE.

关键词： controllers

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New simplified model for an under-actuated quadruped robot in bounding motion

New simplified model for an under-actuated quadruped robot i...

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2011 2nd International Conference on control, Instrumentation and Automation, ICCIA 2011

作者： Kazemi, Hamed Majd, Vahid Johari Moghaddam, Majid M. Intelligent Control Systems Laboratory School of Electrical and Computer Engineering Tarbiat Modares University Tehran Iran Robotics and Mechatronics Laboratory Mechanical Engineering Department Tarbiat Modares University Tehran Iran

ISBN: (纸本)9781467316903

In this paper, a quadruped robot is studied in bounding motion. A new simplified model of quadruped robot in bounding motion with four actuated and two unactuated joints is developed. The kinetic and potential energies of the under-actuated mechanical model of the quadruped robot are obtained and the dynamics of the robot model is derived using the Lagrangian method. It is shown that the dynamical equation of the proposed simplified model belongs to a class of second-order nonholonomic mechanical systems. The main motivation of this paper is to obtain quadruped model in bounding motion such that one can apply different control methods directly or after transformation in the obtained dynamic equations. Utilizing MATLAB, dynamics of the planar model has been simulated in backward and forward states. Physical parameters of the Little-Dog robot as an instance of the quadruped robot are considered in simulation The simulation is without control and therefore is unstable but it illustrates robot's manner in bounding motion before instability. © 2011 IEEE.

关键词： Potential energy

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Canonical estimation in a rare-events regime

Canonical estimation in a rare-events regime

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2011 49th Annual Allerton Conference on Communication, control, and Computing, Allerton 2011

作者： Ohannessian, Mesrob I. Tan, Vincent Y. F. Dahleh, Munther A. Laboratory for Information and Decision Systems Massachusetts Institute of Technology Cambridge MA 02139 United States Department of Electrical and Computer Engineering University of Wisconsin-Madison Madison WI 53706 United States

ISBN: (纸本)9781457718168

We propose a general methodology for performing statistical inference within a 'rare-events regime' that was recently suggested by Wagner, Viswanath and Kulkarni. Our approach allows one to easily establish consistent estimators for a very large class of canonical estimation problems, in a large alphabet setting. These include the problems studied in the original paper, such as entropy and probability estimation, in addition to many other interesting ones. We particularly illustrate this approach by consistently estimating the size of the alphabet and the range of the probabilities. We start by proposing an abstract methodology based on constructing a probability measure with the desired asymptotic properties. We then demonstrate two concrete constructions by casting the Good-Turing estimator as a pseudo-empirical measure, and by using the theory of mixture model estimation. © 2011 IEEE.

关键词： Probability

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Knowledge-based diagnosis of process systems using procedure HAZID information

Knowledge-based diagnosis of process systems using procedure...

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Lecture Notes in computer Science

作者： Werner-Stark, Ágnes Németh, Erzsébet Hangos, Katalin M. Department of Electrical Engineering and Information Systems University of Pannonia Veszprém Hungary School of Chemical Engineering University of Queensland Brisbane QLD Australia Process Control Research Group Systems and Control Laboratory Computer and Automation Research Institute Budapest Hungary

ISBN: (纸本)9783642238536

Earlier investigations show that the results of hazard identification (HAZID) and analysis (e.g. HAZOP or FMEA) can effectively be used for knowledge-based diagnosis of complex process systems in their steady-state operation. In order to extend this approach for transient operating conditions controlled by operating procedures, the notion of nominal input-output event sequences of qualitative signals has been introduced, and the deviations used in the procedure HAZID analysis have been defined therefrom. The diagnosis can then be performed algorithmically by matching the deviation sequences of the observed input-output event sequences and the nominal ones generated by qualitative dynamic models. The concepts and methods are illustrated using a simple case study consisting of a simple tank, controlled by an operating procedure. © 2011 Springer-Verlag.

关键词： Hazards

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On the polyhedral set-invariance conditions for time-delay systems

On the polyhedral set-invariance conditions for time-delay s...

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作者： Lombardi, Warody Olaru, Sorin Lazar, Mircea Bitsoris, Georges Niculescu, Silviu-Iulian Automatic Control Department France LSS - Laboratory of Signals and Systems SUPELEC CNRS Gif-sur-Yvette France Department of Electrical and Computer Engineering University of Patras Patras Greece Department of Electrical Engineering Eindhoven University of Technology Eindhoven Netherlands

ISBN: (纸本)9783902661937

In this paper the concept of set invariance for time-delay systems is introduced with a specific attention to the linear discrete-time case. We are interested in the definition of a D(elay)-invariant set with respect to a bounded polyhedral subset of the state-space. D-invariance conditions are derived based on the Minkowski addition in a first stage, and subsequently translated in feasibility-based tests in order to obtain an efficient computation time. © 2011 IFAC.

关键词： Time delay

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A Dual Comparison Principle for the Analysis and Design of Discrete-Time Dynamical systems

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IFAC Proceedings Volumes 2011年第1期44卷 6437-6442页

作者： George Bitsoris Nikolaos Athanasopoulos Control Systems Laboratory Department of Electrical and Computer Engineering University of Patras 26500 Patras Greece

Abstract In this article, two new comparison principles for studying positive invariance and stability of linear and nonlinear discrete-time systems are presented. First, a general comparison principle enabling one to determine necessary and sufficient conditions of positive invariance of sets described by their “border surfaces” is developed. Then, a dual comparison principle describing the dynamics of the “vertices” of these sets is established. Both results can be used for the stability analysis and the control design of nonlinear systems.

关键词： comparison principle discrete-time systems positive invariance stability nonlinear systems

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