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Selecting nonlinear model structures for computer control

JOURNAL OF PROCESS CONTROL 2003年第1期13卷 1-26页

作者： Pearson, RK Tampere Univ Technol TICSP FIN-33101 Tampere Finland

Many authors have noted the difficulty of developing the models required for nonlinear model predictive control (NMPC) and other nonlinear, model-based control strategies. One reason this task is difficult is that success depends strongly on initially selecting a reasonable structure for this nonlinear model. Unfortunately, this selection is extremely difficult because most of our intuition about structure/behavior relations (e.g., if the step response exhibits overshoot, a model of at least second order is required) is based on experience with relatively low-order linear models and often fails completely when confronted with comparably simple nonlinear models. To help bridge this chasm between nonlinear model behavior and our linear intuition, this paper describes some broad classes of nonlinear model structures, which may be approximately characterized as mildly nonlinear, strongly nonlinear, or of intermediate nonlinearity, depending on the different ways they violate linear intuition. It is hoped that these results will be useful in selecting simple nonlinear model structures for use in model-based control. (C) 2002 Published by Elsevier Science Ltd.

关键词： Multiple steady-states Predictive control Wiener model estimation algorithm Hammerstein models Adaptive-control Narmax models Identification Systems Distillation Predictive control Intuition adaptive control nonlinear model predictive control Nonlinear Models Distillation nonlinearity distilling

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NONINVASIVE FLOW estimation OF A ROTARY VENTRICULAR ASSIST DEVICE

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IFAC Proceedings Volumes 2002年第1期35卷 205-210页

作者： Yih-Choung Yu Kirk A. Lehmann John Chiasson Dept. of Electrical & Computer Eng. Lafayette College Easton PA 18042 USA CardiacAssist Inc. Pittsburgh PA 15238 USA Dept. of Electrical & Computer Eng. U. of Tennessee Knoxville TN 37996 USA

An estimator identifying the flow rate through a rotary blood pump was developed. This estimation algorithm uses the pump current and speed signals to estimate the blood flow rate through the pump. The algorithm was derived based on the force balance between the electric torque generated by the motor and the load torque, including the mechanical losses. The corresponding estimator parameters were identified using experimental data in the laboratory. The estimator performed well in mock circulatory loop experiments simulating different physiologic conditions. This algorithm will be implemented in a single board computer to estimate the flow rate of the rotary pump in an implantable left ventricular assist device without invasive sensors.

关键词： biomedical system medical application estimation algorithm

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Feature Extraction of Localized Scattering Centers Using the Modified TLS-Prony algorithm and Its Applications

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Journal of Systems Engineering and Electronics 2002年第3期13卷 31-39页

作者： Wang Jun Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, P.R.China Institute of Electronic Engineering China Academy of Engineering Physics Mianyang 621900 P. R. China

This paper presents an all-parametric model of radar target in optic region, in which the localized scattering center's frequency and aspect angle dependent scattering level, distance and azimuth locations are modeled as the feature vectors. And the traditional TLS-Prony algorithm is modified to extract these feature vectors. The analysis of Cramer-Rao bound shows that the modified algorithm not only improves the restriction of high signal-to-noise ratio(SNR)threshold of traditional TLS-Prony algorithm, but also is suitable to the extraction of big damped coefficients and high-resolution estimation of near separation poles. Finally, an illustrative example is presented to verify its practicability in the applications. The experimental results show that the method developed can not only recognize two airplane-like targets with similar shape at low SNR, but also compress the original radar data with high fidelity.

关键词： Localized scattering centers estimation algorithm Low SNR High resolution.

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SINGULARITY-FREE STABLE ADAPTIVE CONTROL OF A CLASS OF NONLINEAR DISCRETE-TIME SYSTEMS

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IFAC Proceedings Volumes 2002年第1期35卷 475-480页

作者： Leonid S. Zhiteckij Int. Centre of Inform. Technologies & Systems Institute of Cybernetics 40 Prospect Akademika Glushkova MSP 03680 Kiev 187 Ukraine

This paper deals with the adaptive control of linearly parameterized discrete-time nonlinear system in the presence of bounded disturbances and unmodeled dynamics. A new adaptive law is presented. No a priori knowledge about the bounds on both the plant parameters and unmodeled uncertainty is required to implement the estimation algorithm. The adaptive scheme is free from singularity. This is achieved through the use of some time-varying adaptation gain. It is established that if the plant model nonlinearity is sector-bounded then the BIBO stability of the closed-loop system will be guaranteed. Simulation results are given to demonstrate the performance of the adaptive controller.

关键词： Adaptive control convergence analysis discrete-time systems estimation algorithm nonlinear control systems parametrization stability analysis

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Feature Extraction of Localized Scattering Centers Using the Modified TLS-Prony algorithm and Its Applications

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Chinese Journal of Systems Engineering and Electronics 2002年第3期000卷

This paper presents an all-parametric model of radar target in optic region, in which the localized scattering center's frequency and aspect angle dependent scattering level, distance and azimuth locations are modeled as the feature vectors. And the traditional TLS-Prony algorithm is modified to extract these feature vectors. The analysis of CramerRao bound shows that the modified algorithm not only improves the restriction of high signal-to-noise ratio (SNR)threshold of traditional TLS-Prony algorithm, but also is suitable to the extraction of big damped coefficients and highresolution estimation of near separation poles. Finally, an illustrative example is presented to verify its practicability in the applications. The experimental results show that the method developed can not only recognize two airplane-like targets with similar shape at low SNR, but also compress the original radar data with high fidelity.

关键词： Localized scattering centers estimation algorithm Low SNR High resolution

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Test bed for vehicle longitudinal control using chassis dynamometer and virtual reality: An application to adaptive cruise control

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KSME INTERNATIONAL JOURNAL 2001年第9期15卷 1248-1256页

作者： Won, M Kim, SS Kang, BB Jung, HA Chungnam Natl Univ Dept Mechatron Taejon 305764 South Korea

In this study, a test bed for vehicle longitudinal control is developed using a chassis dynamometer and real time 3-D graphics. The proposed test bed system consists of a chassis dynamometer on which test vehicle can run longitudinally, a video system that shows virtual driver view, and computers that control the test vehicle and realize the real time 3-D graphics. The purpose of the proposed system is to test vehicle longitudinal control and warning algorithms such as Adaptive Cruise Control(ACC), stop and go systems, and collision warning systems. For acceleration and deceleration situations which only need throttle movements, a vehicle longitudinal spacing control algorithm has been tested on the test bed. The spacing control algorithm has been designed based on sliding mode control and road grade estimation scheme which utilizes the vehicle engine torque map and gear shift information.

关键词： ACC (Adaptive Cruise Control) chassis dynamometer 3-D real time graphics sliding mode control ETC (Electronic Throttle Control) estimation algorithm

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Optimal software rejuvenation policy with discounting

Optimal software rejuvenation policy with discounting

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8th Pacific Rim International Symposium on Dependable Computing (PRDC 2001)

作者： Dohi, T Danjou, T Okamura, H Hiroshima Univ Dept Informat Engn Higashihiroshima 7398527 Japan

ISBN: (纸本)0769514146

Software rejuvenation is a preventive maintenance technique that has been extensively studied in the recent literature. In this paper, we consider a generalized problem to estimate the optimal software rejuvenation schedule. More precisely, the software rejuvenation model is formulated via the semi-Markov process, and the optimal software rejuvenation schedule which minimizes the expected total discounted cost over an infinite time horizon is derived analytically. Further, we develop a statistically non-parametric algorithm to estimate the optimal software rejuvenation schedule, provided that the complete sample data of failure time is given. In numerical examples, we investigate how the discount factor affects the optimal policy and examine an asymptotic property for the statistical estimation algorithm.

关键词： preventive maintenance software rejuvenation cost model semi-Markov process modified TTT statistics estimation algorithm

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Computation and analysis of image motion: A synopsis of current problems and methods

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INTERNATIONAL JOURNAL OF COMPUTER VISION 1996年第1期19卷 29-55页

作者： Mitiche, A Bouthemy, P INST NATL RECH INFORMAT & AUTOMAT IRISA F-35042 RENNES FRANCE

The goal of this paper is to offer a structured synopsis of the problems in image motion computation and analysis, and of the methods proposed, exposing the underlying models and supporting assumptions. A sufficient number of pointers to the literature will be given, concentrating mostly on recent contributions. Emphasis will be on the detection, measurement and segmentation of image motion. Tracking, and deformable motion isssues will be also addressed. Finally, a number of related questions which could require more investigations will be presented.

关键词： Optical-flow fields Closed-form solutions Active shape models Visual-motion Moving-objects Vector-fields Smoothness constraints estimation algorithm Posed problems Feature points Closed-form solutions Active shape model Feature Points images

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STATE-SPACE BASED DUAL-RATE SELF-TUNING

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AUTOMATICA 1994年第12期30卷 1999-2007页

作者： AHMED, MS [a]Department of Electrical and Computer Engineering University of Michigan Dearborn MI 48128 U.S.A.

A state space based dual-rate self-tuning algorithm is proposed for the case where the output sampling rate is slower than the input update rate, A state space innovation model suitable for dual-rate self-tuning control is derived. The parameters of the innovation model together with the states are estimated by a recursive prediction error estimator. The control strategy has been based on a pole restriction principle. Simulation studies are presented to establish the practical usefulness of the algorithm.

关键词： ADAPTIVE CONTROL SELF-TUNING CONTROL COMPUTER CONTROLLED SYSTEM STOCHASTIC SYSTEM estimation algorithm STATE FEEDBACK

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HOMOMORPHIC LINEAR PREDICTIVE CODING - A NEW estimation algorithm FOR ALL-POLE SPEECH MODELING

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IEE PROCEEDINGS-I COMMUNICATIONS SPEECH AND VISION 1990年第2期137卷 103-108页

作者： HUANG, Z YANG, X ZHU, X KUH, A TSING HUA UNIV DEPT RADIO ELECTRBEIJINGPEOPLES R CHINA

Conventional LPC algorithms give biased estimates for voiced speech signals in the case of pitch-asynchronous analysis. This paper presents a new estimation algorithm for an all-pole model, named as homomorphic linear predictive coding (HLPC) which models the vocal tract transfer function as an all-pole filter, but performs the estimation of the filter coefficients in the cep-strum domain by a minimum mean squared error method. By limiting the summation interval of squared errors in the cepstrum domain to the low time portion that is not affected by pitch components, the estimation results obtained by HLPC are unbiased and independent of the exciting signal type. Experiments on spectrum estimation and formant estimation under several conditions have been carried out for comparison. It is shown that for pitch-asynchronous analysis, HLPC has a higher accuracy than LPC in spectrum estimation as well as formant frequency and bandwidth estimation, especially for speech signals with high pitch frequencies.

关键词： Simulation, modelling and identification estimation algorithm pitch-asynchronous analysis bandwidth estimation high pitch frequency speech signals all-pole filter homomorphic linear predictive coding Codes spectrum estimation filtering and prediction theory speech analysis and processing minimum mean squared error method encoding cepstrum domain all-pole speech modelling Speech and audio signal processing spectral analysis Speech recognition formant frequency estimation vocal tract transfer function Information theory parameter estimation speech synthesis

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