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The Exact Velocity Linearization Method

IFAC Proceedings Volumes 2003年第18期36卷 259-264页

作者： Miroslav Halás Mikuláš Huba Katarína Žáková Department of Automation and Control Faculty of Electrical Engineering and Information Technology Slovak University of Technology Ilkovičova 3 812 19 Bratislava Slovakia

The aim of this paper is to present a new method for the nonlinear controller design. The underlying theory evolves from the introduced transfer function of nonlinear systems, that can be used in similar way as transfer functions of classical linear systems. The presented algebra of transfer functions is the same as the linear one. Therefore, the controller design can follow the linear system synthesis. The paper shows, how to design a nonlinear PID controller using the direct method synthesis and also shows that the nonlinear state controller following the pole-placement method is equivalent to the exact linearization method. Since the presented method leads to results identical with the exact linearization method, it has been denoted as the exact velocity linearization method.

关键词： nonlinear system velocity linearization transfer function PID controller state controller

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OPTIMIZING THE SUBDIVISION OF ELEMENTS IN DISCONTINUITY MESHING FOR HIERARCHICAL RADIOSITY

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International Journal on Artificial Intelligence Tools 2003年第4期12卷 395-411页

作者： IOANNIS A. PANTAZOPOULOS SPYROS G. TZAFESTAS Intelligent Robotics and Automation Laboratory Signals Control and Robotics Division Electrical and Computer Engineering Department National Technical University of Athens Zographou Athens Greece

This paper presents a new topological structure for use in the context of hierarchical radiosity combined with discontinuity meshing. This is most useful for a new strategy adopted for subdividing the elements of a scene consisting of convex polygons. The subdivision is done in a local optimization manner keeping the aspect ratios of produced polygons low. The generated meshes give high visual accuracy.

关键词： Hierarchical radiosity discontinuity meshing mesh pre(post)-processing multigriding aspect-ratio

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New in situ sensor modeling approach to measurement validation

New in situ sensor modeling approach to measurement validati...

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作者： Srinivasagupta, Deepak Joseph, Babu Morley, Robert E. Process Control Systems Laboratory Department of Chemical Engineering Washington University One Brookings Drive St. Louis MO 63130 United States Electronic Systems Laboratory Department of Electrical Engineering Washington University One Brookings Drive St. Louis MO 63130 United States Department of Chemical Engineering University of South Florida ENB 118 4202 E. Fowler Avenue Tampa FL 33260 United States

Measurement error due to sensor degradation (fouling, miscalibration, etc.) is more difficult to identify compared to catastrophic sensor failure. Passive methods previously proposed for sensor-level monitoring are based on power spectrum or multiscale analysis of sensor data. These methods have limitations caused by not accounting for various noise sources and assumptions about sensor noise characteristics, thus resulting in false and missed alarms. In this paper, an online sensor fault detection scheme based on the identification of sensor response characteristics is proposed and evaluated. We develop both robust passive and active in situ techniques to identify sensor response characteristics that relate directly to its health. Using the identified sensor model, various kinds of sensor faults are quantified and mapped into the model parameters. A dynamic model-based estimator is proposed for data reconciliation. These ideas were experimentally validated using thermocouples, flowmeters, and resistance thermometric devices on laboratory-scale processes. The proposed approach was seen to accurately quantify the sensor model parameters and aid in measurement reconstruction.

关键词： Chemical sensors

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Near minimax robust control of flexible structures

Near minimax robust control of flexible structures

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American control Conference (ACC)

作者： M. Muenchhof T. Singh Department of Mechanical and Aerospace Engineering SUNY at Buffalo Buffalo NY USA Institute of Automatic Control Laboratory of Control Systems and Process Automation Darmstadt University of Technology Darmstadt Germany

This paper presents an approach to calculate prefilters that are insensitive to parameter deviations. The cost function chosen for this approach is the magnitude of the time-delay filter transfer function. By approximating the cost function with a polynomial, the effort of calculating minimax robust profiles can be reduced. The resulting control profiles yield a performance similar to the minimax robust controller. This is verified by the numerical results included in this paper.

关键词： Minimax techniques Robust control Flexible structures Filters Uncertainty Frequency Cost function Vibrations control systems Delay effects

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An infeasibility degree selection based genetic algorithms for constrained optimization problems

An infeasibility degree selection based genetic algorithms f...

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System Security and Assurance

作者： Mu, Sheng-Jing Su, Hong-Ye Chu, Jian Wang, Yue-Xuan Natl. Lab. of Indust. Cntr. Technol. Inst. of Adv. Process Control Zhejiang University Yuquan Campus Hangzhou 310027 China Natl. CIMS Engineering Res. Center Inst. of System Integration Department of Automation Beijing 100084 China

ISBN: (纸本)0780379527

In this paper, a genetic algorithm based on Infeasibility Degree (IFD) selection is proposed for constrained optimization problems. Initial solutions and intermediate solutions are allowed to be feasible as well as infeasible as penalty function methods. The infeasibility degree of a solution (IFD) is defined as the sum of the square value of all the constraints violation and the infeasibility degree selection of the population is designed through checking whether the IFD of a solution is less than or equal to a threshold value or not to decide the candidate solution is acceptable or refusable. The method is divided into two stages: first, initial IFD selection is carried out to produce enough initial feasible solution;then the GAs based on Annealing IFD selection is applied to search for the feasible optimum solution. Two selected problems are used to test the algorithm performance.

关键词： control system analysis

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Reduction of the Optimization Efforts with Predictive control by Using Non-Equidistant Prediction Points

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IFAC Proceedings Volumes 2003年第8期36卷 57-62页

作者： U. Schmitz R. Haber R. Bars Department of Plant and Process Engineering Laboratory of Process Control University of Applied Science Cologne D-50619 Köln Betzdorf er Str. 2 Germany fax: +49-221-8275-2836 Department of Automation and Applied Informatics MTA-BME Control Research Group Budapest University of Technology and Economics Hungary

With predictive control most of the computation time is spent for the simulation of the predicted variables and for the optimization if constraints or nonlinear processes are assumed. In addition to the known blocking technique for the manipulated variable another possibility is calculating the control error not in each sampling point of the prediction horizon but only in some coincidence points. It will be shown that the best choice is to allocate the coincidence points exponentially thus that with small prediction steps more and with increasing prediction steps less coincidence points are considered. As a practical example the multivariable control of a distillation column model illustrates the benefits of the method presented.

关键词： Predictive control optimal control control applications chemical industry execution time

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Long-range optimal model and multi-step-ahead prediction identification for predictive control

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IFAC Proceedings Volumes 2003年第16期36卷 477-482页

作者： R. Haber U. Schmitz R. Bars Department of Plant and Process Engineering Laboratory of Process Control University of Applied Science Cologne D-50679 Köln Betzdorfer Str. 2 Germany fax: +49-221-8275-2836 Department of Automation and Applied Informatics Control Research Group of the Hungarian Academy of Sciences Budapest University of Technology and Economics Hungary

Long-range optimal prediction algorithms use the predicted output for several steps ahead. The prediction based on traditionally estimated model parameters does not result in an optimal prediction if the measurements are noisy or/and model structure differs from real process structure. In this paper two different identification schemes are presented and compared: long-range predictive single-model identification and simultaneous multi-step-ahead prediction identification. It is shown that the first method is easier to realize but the second one leads to more accurate results. Both methods are derived for a first-order model in details. Simulation runs and a level control example illustrate the algorithms presented.

关键词： process identification prediction parameter estimation predictive control

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Optimization of PM brushless DC motor drive

Optimization of PM brushless DC motor drive

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IEEE International Conference on Industrial Technology (ICIT)

作者： P. Crnosija T. Bjazic R. Krishnan Faculty of Electrical Engineering and Computing Department of Control and Comp. Eng. in Automation University of Zagreb Zagreb Croatia The Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University Blacksburg VA USA

Traditional approaches to controller designs that guarantee fast compensation of load torque and reference variations result in design iterations and most of the time in poorer response for load torque variations. In this paper a reference model for desired drive behavior generation and optimization methods has been applied to achieve controller integral time constant lower than the maximum time constant of the PM brushless DC motor drive. Presented simulation results show that using reference model for desired drive behavior generation, it is possible to determine optimal controller parameters for faster (10 time) and better (2 time) load torque compensation than in the case of traditional design of speed controller parameters. Response due to reference input with constrained overshoot has been achieved using a filter in the servosystem input. Thereby, the proposed method demonstrates the design of a speed controller that is optimal for both load torque and reference variations and its verification with simulation are accomplished for a permanent magnet brushless dc motor drive.

关键词： Brushless DC motors Torque control Optimal control Time factors DC generators Optimization methods Magnetic separation Filters Servosystems Design methodology

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An efficient information server for advanced plant asset management

An efficient information server for advanced plant asset man...

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International Conference on Emerging Technologies and Factory automation (ETFA)

作者： J. Muller U. Epple M. Wollschlaeger C. Diedrich Department of Process Control Engineering RWTH Aachen Aachen Germany Ifak-Institut für Automation und Kommunikation e.V. Magdeburg Barleben Germany

In already installed fieldbus instrumentations, a configuration-free and manufacturer-independent access to field device information sets is still missing. Due to the lack of suitable and simple models, as well as of interaction patterns of field devices in various information worlds of process control engineering, the practical use made of device novelties is rather complex. This affects high investments for engineering this information in various applications of process control engineering. Modern field devices contain embedded information sets that are ever-increasing, and provide great opportunity for innovative asset management functionality. In this paper we present an information server, serving as an additional information channel between field and plant level in process industry. We show that this so-called asset management box provides the configuration-free analysis of fieldbus segments, the open access to installed field devices and the automatically updated, structured and self-descriptive presentation of their embedded information sets. Its basic functionality fulfills one prerequisite of an efficient asset management system: the analysis of the actual state of a fieldbus installation, without prior knowledge about the installed field devices and enhanced investments in engineering. We discuss several asset management applications, implemented on the asset management box. To prevent excessive investments for engineering of asset management applications themselves, widest flexibility and extensibility of the management systems' functionality is required. The box's structure permits easy extensibility of plant and client-specific applications as well as the easy integration of specific fieldbus hardware, the box provides a universal fieldbus interface.

关键词： Asset management Field buses Investments process control Instruments Manufacturing electrical equipment industry Information analysis Knowledge engineering engineering management

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Direct Learning control Design for a Class of Linear Time-varying Switched Systems

Direct Learning Control Design for a Class of Linear Time-va...

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International Conference on control and automation (ICCA)

作者： Jian-Xin Xu P. Korondi Rui Yan Zhi-Hong Guan Department of Electrical and Computer Engineering National University of Singapore Singapore Department of Automation and Applied Informatics Budapest University of Technology and Economics Wuhan China Department of Control Science and Engineering Huazhong University of Science and Technology Wuhan China

In this paper, a direct learning control method for a class of switched systems is proposed. The objective of direct learning is to generate the desired control profile for a newly switched system without any feedback, even if the system may have uncertainties. This is achieved by exploring the inherent relationship between any two systems before and after a switch. The new method is applicable to a class of linear time varying, uncertain and switched systems, when the trajectory tracking control problem is concerned. A numerical simulation demonstrates the effectiveness of the proposed method.

关键词： control design Time varying systems Switched systems control systems Switches Feedback Uncertainty Trajectory Numerical simulation

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