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Efficient shape control of distributed reflectors with discrete piezoelectric actuators

JOURNAL OF INTELLIGENT MATERIAL systemS AND STRUCTURES 2004年第1期15卷 3-15页

作者： Andoh, FH Washington, G Yoon, HS Utkin, V Ohio State Univ Columbus OH 43210 USA

In the current article, a novel approach to the shape control problem with a limited number of discrete actuators is presented. In optimizing the actuator locations, first the reference input was expanded with a representative set of eigenfunctions. From the expansion coefficients, the dominant modes in the reference input were identified. Next the distributed parameter system was rewritten in modal coordinates and the irrelevant modes were truncated. Finally, the actuator locations were selected such that the singular values of the controllability matrix of the truncated system were maximized. The steady state actuation forces were optimized such that a cost function based on the absolute value of the steady state error is minimized. To improve the transient response, a hybrid of dynamic modal control algorithm and the optimization method is developed. Four discrete linear actuators for the one-dimensionally curved reflector and eight actuators for the two-dimensionally curved reflector are utilized. The structures are controlled and assessments for experimental implementation are made.

关键词： mechanically reconfigurable antenna shape control optimization method distributed parameter system singular value decomposition

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Soft computing applications in dynamic model identification of polymer extrusion process

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APPLIED SOFT COMPUTING 2004年第4期4卷 345-355页

作者： Tan, LP Lotfi, A Lai, E Hull, B Nottingham Trent Univ Sch Comp & Technol Nottingham NG1 4BU England

This paper proposes the applications of soft computing to deal with the constraints in conventional modelling techniques of the dynamic extrusion process. The proposed technique increases the efficiency in utilising the available information during the model identification. The resultant model can be classified as a 'grey-box model' or has been termed as a 'semi-physical model' in the context. The extrusion process contains a number of parameters that are sensitive to the operating environment. Fuzzy rule-based system (FRBS) is introduced into the analytical model of extrusion by means of sub-models to approximate those operational-sensitive parameters. In drawing an optimal structure for each sub-model, a hybrid algorithm of genetic algorithm with fuzzy system ( GA-fuzzy) has been implemented. The sub-models obtained show advantages such as linguistic interpretability, simpler rule-base and less membership functions (MFs). The developed model is adaptive with its learning ability through the steepest decent error back-propagation algorithm. This ability might help to minimise the deviation of the model prediction when the operational-sensitive parameters adapt to the changing operating environment in the real situation. The model is first evaluated through simulations on the consistency of model prediction with the theoretical analysis. Then, the usefulness of adaptive sub-models during the operation is further explored in existence of prediction error. (C) 2004 Elsevier B.V. All rights reserved.

关键词： dynamic modelling soft computing GA-fuzzy algorithm steepest decent error back-propagation semi-physical modelling distributed parameter system adaptive polymer extrusion

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Control design for galerkin approximations of a flexible structure

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IFAC Proceedings Volumes 2004年第17期37卷 311-318页

作者： Alexander Zuyev Oliver Sawodny Institute for Automation and Systems Engineering Technical University of Ilmenau P.O.B. 100565 D-98684 Ilmenau Germany Institute of Applied Mathematics and Mechanics National Acad. of Sciences of Ukraine R. Luxembourg 74 88114 Donetsk Ukraine

A hybrid control system describing the dynamics of a flexible robot manipulator is considered. For the distributed parameter part of this system, we construct a family of Galerkin approximations based on solutions of the homogeneous Timoshenko beam equation. We derive necessary and sufficient conditions for controllability of such finite dimensional system. In addition, the equilibrium of the Galerkin approximation considered is proved to be stabilizable by a state feedback law, and an explicit stabilizer is proposed.

关键词： distributed parameter system Galerkin approximation stabilization Lyapunov function flexible manipulator

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Observer design for a towed seismic streamer cable

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IFAC Proceedings Volumes 2004年第10期37卷 137-142页

作者： Tu Duc Nguyen Olav Egeland Department of Engineering Cybernetics Norwegian University of Science and Technology

In this paper, observer design for a towed seismic streamer cable is considered. Based on measurements at the boundaries, an uniformly exponentially stable observer is proposed. The stability analysis of the observer is based on Lyapunov theory. The existence and uniqueness of the solutions of the observer are based on semigroup theory. To illustrate the performance of the observer, numerical simulation results are presented.

关键词： distributed parameter system Cable Observer

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Experimental Modeling of a Biofilter for Combined Adsorption and Nitrification

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IFAC Proceedings Volumes 2004年第3期37卷 159-164页

作者： Jens E. Haag Alain Vande Wouwer Etienne Paul Isabelle Queinnec Service d'Automatique Faculté Polytechnique de Mons 31 Boulevard Dolez. B-7000 Mons Belgium Laboratoire d'1ngénierie des Procédés de l'Environnement Institut National des Sciences Appliquées 135 Avenue de Rangueil F-31077 Toulouse Cedex 4 France Laboratoire d'Analyse et d'Architecture des Systèmes Centre National de la Recherche Scientifique 7 Avenue du Colonel Roche F-31077 Toulouse Cedex 4 France

Biofilters consisting of packed bed columns are efficient devices for purification of ground- or wastewater from solid and toxic components. In this work, a biofilter for nitrification is equipped with a porous bed of Manganese dioxide particles, which offers the support for the formation of a biofilm and which, in addition, adsorbs ammonium. Experiments are performed to study the distributed parameter behavior of key state variables, e.g. biomass and nitrogenous components, and a dynamic model described by partial differential equations is derived. Several unknown model parameters are estimated from measurements collected in the course of these experiments. The resulting model is in good agreement with the experimental data.

关键词： Model identification distributed parameter system biofilter nitrification adsorption

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Model-Based Trajectory Control of Pressure Swing Adsorption Plants

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IFAC Proceedings Volumes 2004年第1期37卷 565-570页

作者： M. Bitzer K. Graichen M. Zeitz Institut für Systemdynamik und Regelungstechnik Universität Stuttgart Pfaffenwaldring 9 70550 Stuttgart Germany

Pressure swing adsorption (PSA) plants consist of several fixed-bed adsorbers and are operated as cyclic multi-step processes. PSA processes are used for the separation and purification of gas mixtures. Based on a rigorous distributed parameter model of the considered 2-bed PSA plant, a process control scheme is derived which is composed of a nonlinear feedforward control and a linear feedback control. For the design of the feedforward control, a numerical approach for the inversion of the rigorous plant model is presented. The designed trajectory control scheme is evaluated by use of the PSA plant simulation model

关键词： multi-step process periodic process operation distributed parameter system adsorption process nonlinear travelling concentration waves numerical model inversion feedforward control feedback control

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Boundary feedback spectrum shift for distributed parameter systems on a planar domain

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART I-JOURNAL OF systemS AND CONTROL ENGINEERING 2003年第I2期217卷 73-81页

作者： Lu, SH Fong, IK Natl Taiwan Univ Dept Elect Engn Taipei 10617 Taiwan

For a special class of linear distributed parameter systems defined on a planar domain and controlled by boundary inputs, a systematic procedure is established to reformulate them as systems defined over certain interpolation spaces. Based on this result, it is shown how certain spectrum shift can be achieved by using boundary state feedback control. An example is used to demonstrate the theoretical results.

关键词： distributed parameter system boundary control spectrum shift

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Control of the temperature distribution in two dimensional space of an annular type non-isothermal adsorber

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JOURNAL OF PROCESS CONTROL 2003年第8期13卷 831-838页

作者： Yoshida, M Takeda, T Maruko, M Matsumoto, S Tohoku Univ Dept Chem Engn Aoba Ku Sendai Miyagi 9808579 Japan

A new annular-type non-isothermal adsorber is proposed, which makes it possible to separate a multi-components gas mixture continuously. For the effective operation of the adsorber, it is essential to control the temperature distribution in the two dimensional space (axial and angular direction) of the adsorber. In this work, the controller design is based on a method reducing distributed parameter system (DPS) to lumped parameter system (LPS) through the eigenfunction expansion. The advantage of this method is that the design of the feedback controller is very simple because the reduced LPS model is completely decoupled. The results show that the whole temperature distribution in the adsorber is estimated accurately from several measurements by using the Kalman filter as an observer. The designed servo controllers' performances are satisfactory in spite of using the reduced order LPS model. (C) 2003 Elsevier Ltd. All rights reserved.

关键词： process control distributed parameter system adsorption temperature profile state estimation

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Model reference adaptive control of a cantilevered flexible beam

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JSME INTERNATIONAL JOURNAL SERIES C-MECHANICAL systemS MACHINE ELEMENTS AND MANUFACTURING 2003年第2期46卷 640-651页

作者： Yang, KJ Hong, KS Yoo, WS Matsuno, U Pusan Natl Univ Sch Mech Engn Pusan 609735 South Korea Tokyo Inst Technol Midori Ku Yokohama Kanagawa 2268502 Japan

In this paper, model reference adaptive control of a cantilevered flexible beam with Kelvin-Voigt damping and unknown spatially varying coefficients is investigated. Any mechanically flexible robots/structures are inherently distributed parameter systems whose dynamics are described by partial, rather than ordinary, differential equations. Adaptation laws are derived by the Lyapunov redesign method on an infinite dimensional Hilbert space. To show the well-posedness of a coupled nonlinear system, combined state error and parameter estimation error equations are constructed as an initial value problem of an infinite dimensional evolution equation in weak form. It is then shown through the Lyapunov redesign approach that the state error actually converges asymptotically to zero. With an additional persistence of excitation assumption, the parameter estimation errors are shown to converge to zero as well.

关键词： model reference adaptive control cantilevered flexible beam stability persistence of excitation distributed parameter system

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Experimental model determination for neurocontrol of a thermal conduction system

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JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER 2003年第4期17卷 471-480页

作者： Prabhat, P Look, DC Balakrishnan, SN Univ Missouri Dept Mech & Aerosp Engn & Engn Mech Rolla MO 65409 USA

Recently a synthesis methodology for the infinite time optimal neurocontrollers for partial differential equations systems in the framework of adaptive-critic design has been developed. The adaptive-critic approach is applied to a thermal conduction system. The experimental setup representing a one-dimensional heat conduction problem developed by matching the experimental and simulation results using a tridiagonal-matrix algorithm is presented. The discrete domain forms of the state, the costate and the optimal control equations are derived using the distributed parameter model of the system. The synthesis is introduced of an adaptive-critic-based infinite time optimal neurocontroller for online temperature profile control. The representative states of the system for training the networks was generated using Fourier series-based smooth states profile algorithm. Finally, the action network is implemented for temperature profile control of the experimental setup.

关键词： Thermal Conduction system Costate Equation Thermocouples distributed parameter system Neural Networks Neumann Boundary Condition Mathematical Models DAQ Numerical Simulation Heat Generation

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