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Robust Analysis of Distillation Column Dynamics

IFAC Proceedings Volumes 1995年第9期28卷 333-338页

作者： E.I. Varga G.Z. Kovács S.B. Jørgensen K.M. Hangos Systems and Control Laboratory Computer and Automation Research Institute Department of Chemical Engineering The Technical University of Denmark Lyngby Denmark

The robust stability and performance of a binary distillation column model is analysed using a minimal state space representation. The uncertainty modelling of the column is resulted in an LFT form with a four element diagonal block structure taking into account the dependence between the steady state gains. Robust analysis of the distillation column dynamics is performed and compared using µ - and l 1 -analysis tools. The magnitude of possible overshoots is determined by l 1 -test for robust performance and the dependence of this magnitude on the dominant time constant (i.e. the purity of the separation) is investigated. Futhermore the effect of the mi certainties in the time constants and the singular values on the robust performance is also analysed using l 1 -test. It has been found that the uncertainty in the time constants affects dominantly the robust performance of the open-loop system, i.e. the magnitude of possible overshoots.

关键词： Distillation column parametric uncertainty modelling robust stability robust performance

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Synthesized passive feedback control of sensor-rich smart structures-experimental results

Synthesized passive feedback control of sensor-rich smart st...

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IEEE Conference on control Technology and Applications (CCTA)

作者： P. Akella J.T. Wen Control Laboratory for Mechanical Structures Department of Electrical Computer and Systems EngineeringCenter for Advanced Technology in Automation Robotics & Manufacturing Rensselaer Polytechnic Institute RPI Troy NY USA

Passivity based controllers are used in structural control due to their inherent robustness properties. These controllers require sensor/actuator collocation. In this paper, we consider the design of a "squaring down" matrix which renders a system passive by using a linear combination of all collocated and non-collocated sensor/actuator pairs. The design uses experimental transfer functions and does not require the knowledge of the system model. The problem of finding the squaring down matrix is cast as a solution to a set of linear matrix inequalities (LMIs) subject to some additional performance considerations. The design procedure of the squaring down matrix assumes that velocity information is available from the sensors which is not generally the case. We show that the squaring down matrix can be implemented without the use of such velocity information. We provide experimental results gathered from the single link flexible beam setup in the C/sub La/MS laboratory at RPI to show that implementation of passive loops without velocity measurements provides very good results.

关键词： Feedback control Linear matrix inequalities Intelligent sensors control system synthesis Robust control Sensor systems Hydraulic actuators Transfer functions Laboratories Economic indicators

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Preisach modeling of piezoceramic and shape memory alloy hysteresis

Preisach modeling of piezoceramic and shape memory alloy hys...

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IEEE Conference on control Technology and Applications (CCTA)

作者： D. Hughes J.T. Wen Control Laboratory for Mechanical Structures (CLaMS) Center for Advanced Technology in Automation Robotics & Manufacturing Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy NY USA

Smart materials such as piezoceramics and shape memory alloys (SMAs) exhibit significant hysteresis and in order to estimate the effect on open and closed loop control a suitable model is needed. One promising candidate is the Preisach independent domain hysteresis model that is characterized by the congruent minor loop and wiping out properties. Comparable minor loop and decaying oscillation test data for a multi-sheet piezoceramic actuator (made of lead zirconate titanate) attached to a flexible beam are presented and are seen to be very consistent with the two Preisach model properties. The commanded parameter is the sheet transverse electric field while the measured parameter is an approximately colocated strain induced in the beam. Equivalent data for a Nitinol SMA wire muscle, attached to the same beam, are also presented. The input and output parameters are the SMA current and a beam strain respectfully. The minor loop and wiping out evidence is less strong than that of the piezoceramic case, but encouraging. In all experiments the quasi-steady state responses were generated in order to avoid exciting beam flexible modes which would complicate the analysis.

关键词： Piezoelectric materials Shape memory alloys Hysteresis Strain measurement Shape control Open loop systems Testing Actuators Titanium compounds Electric variables measurement

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H/sub /spl infin// vibration control of active suspension for automotive application

H/sub /spl infin// vibration control of active suspension fo...

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SICE Annual Conference

作者： A. Kanbolat Y. Okuyama F. Takemori L. Gianone S. Horvat J. Bokor Department of Information and Knowledge Engineering Facult of Engineering Tottori University Japan Tottori Daigaku Tottori JP Dept. of Inf. & Knowledge Eng. Tottori Univ. Japan Systems and Control Laboratory Computer and Automation Research Institute Hungarian Academy of Sciences Hungary Department of Transpoi-talion Engineering Technical University of Budapest Hungary

This paper deals with simultaneous control of acceleration transmission, wheel load fluctuation, suspension deflection and sprung mass displacement. The control theory is based on the robust H/sub /spl infin// control theory with the consideration of the modeling errors lumped into an unstructured uncertainty acting on the unperturbed plant. The design method is new and powerful for electronic car suspension's control systems, as it presents a new approach to the designers for the computation of a controller maintaining robust stability while guaranteeing the performance in a wide frequency range, even in the case of the controller is applied to the actual plant. Additionally, the paper emphasizes that the assumptions in the modeling step may lead to unrealistic control designs and, as an example, the effect of the rigidity assumption on the behavior of the open loop system is discussed.

关键词： control systems control theory Open loop systems Displacement control Weight control Acceleration Wheels Fluctuations Robust control Power system modeling

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Multiagent fault‐diagnosis expert system in power systems

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European Transactions on Electrical Power 1995年第5期5卷 341-347页

作者： Wang, J.P. Trécat, J. Dr. Jianping Wang is a doctor fellow in the Faculte Polytechnique de Mons in Belgium. His current research field is parallel processing applications in power systems. Dr. Wang obtained his BS degree from Southwest Jiaotong University in P.R. Chinain 1982. From 1982 to 1990 he was appointed as an assistant lecturer. lecturer and associate professor respectively in the electrical engineering department of Southwest Jiaotong University. He obtained his Ph.D in the FacultC Polytechnique de Mons in July of 1993. (BD Dolez 3 1 FPMS B-7000 Mons Belgium T +32-65/37 41 87 Fax +32-65/37 43 00) Professor J. Trécat is a director in the power system laboratory in the Faculty Polytechnique de Mons. He obtained his Ph.D in the University of Manchester Institute of Science and Technology(UM1ST) in U.K. in 1970. He has been working in the fields of power system automation artificial intelligence application and computer vision in the Facult6 Polytechnique de Mons since 1970. He is a senior member of IEEE and he has made much contribution both in electrical engineering education and research. (BD Dolez 3 I FPMS B-7000 Mons T +32-651374185. Fax +32-6513743 00)

In order to solve the speed problem and shallow reasoning problem met in current research in fault diagnosis expert system, this paper presents a model based parallel fault diagnosis expert system for energy management systems (EMS). The Petri net model, which corresponds to the relationship between power system components and their protection systems, has been used for the inference in fault diagnosis. A multiagent parallel processing expert system, which is based on five transputers in Sun workstation, has been built for fault diagnosis purposes. The test results show that this expert system is not only fast but also has better performances. Copyright © 1995 John Wiley & Sons, Ltd.

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SUBPIXEL PATTERN-RECOGNITION BY IMAGE HISTOGRAMS

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PATTERN RECOGNITION 1994年第8期27卷 1079-1092页

作者： SZIRANYI, T Analogical and Neural Computing Systems Research Laboratory Computer and Automation Institute Hungarian Academy of Sciences (MTA SZTAKI) P.O. Box 63 H-1518 Budapest Hungary

Recognition of small patterns covering only a few pixels in an image cannot be done by conventional recognition methods. A theoretically new pattern recognition method has been developed for undersampled objects which are (much) smaller than the window-size of a picture element (pixel), i.e. these objects are of subpixel size. The proposed statistical technique compares the gray-level histogram of the patterns of a set of scanned objects to be examined with the (calculated) gray-level densities of different (in shape or size) possible objects, and the recognition is based on this comparison. This method does not need high-precision movement of scanning sensors or any additional hardware. Moreover, the examined patterns should be randomly distributed on the screen, or a random movement of camera is (or target or both are) needed. Effects of noise are analysed, and filtering processes are suggested in the histogram domain. Several examples of different object shapes (triangle, rectangle, square, circle, curving lines, etc.) are presented through simulations and experiments. A number of possible application areas are suggested, including astronomy, line-drawing analysis and industrial laser measurements.

关键词： SUBPIXEL-RECOGNITION HISTOGRAM NOISE FILTERING UNDERSAMPLING SUPERRESOLUTION IMAGE ANALYSIS PATTERN CLASSIFICATION CONVOLUTION STATISTICAL PATTERN RECOGNITION LIGHT-SENSOR ARRAYS DENSITY ESTIMATION

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Robust analysis of potential large overshoots in heat exchanger networks

Robust analysis of potential large overshoots in heat exchan...

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American control Conference (ACC)

作者： E.I. Varga J. Bokor K.M. Hangos Systems and Control Laboratory Computer and Automation Research Institute Budapest Hungary

A robust modeling method of heat exchanger networks (HENs) with structured parametric perturbations has been used in this paper which results in a model in LFT form. The LFT of the overall HEN system can be generated algorithmically from the model of the heat exchangers and from the network topology. Based on these modeling paradigms robust stability and performance tests have been applied using L/sub /spl infin// signal norms in a non-standard way to determine an upper bound for overshoots in HENs. The proposed method has been illustrated on the simple example of a countercurrent heat exchanger with bypass.

关键词： Robustness Intelligent networks Uncertainty Heat transfer Network topology Robust control Temperature measurement Space heating Automatic control control systems

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Grey-Box Modeling for Identification and control: An Emerging Discipline or an Established Technology?

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IFAC Proceedings Volumes 1994年第8期27卷 1193-1198页

作者： S. Bay Jorgensen K.M. Hangos Department of Chemical Engineering Technical University of Denmark Systems and Control Research Laboratory: Computer and Automation Institute HAS

Grey box modeling is a widely used term, which presently reflects that both a priori and experimental knowledge is being incorporated into the model building process. A brief investigation into various uses of grey box modeling approaches reveals that they mainly differ with respect to the required model accuracy. The goal of the model application also has to be considered in the model building, since it constrains the necessary accuracy required by the model. In this paper these two viewpoints are combined thus leading to a proposed new definition of grey box modeling.

关键词： Qualitative differential and algebraic equations Uncertainty representation Verbatim models Robust identification and control Modeling cycle

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Grey Box Identification of Vehicle Dynamics

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IFAC Proceedings Volumes 1994年第8期27卷 1187-1192页

作者： L. Gianone J. Bokor K.M. Hangos Systems and Control Laboratory Computer and Automation Research Institute HAS H-1518 Budapest P.O.B. 63 Hungary

The parametnzation and identification of vehicle vibrating structures are discussed in this paper. The determination of physical parameters from the abstract parameters that represent free coefficients in a transfer function or state space model of the vehicle is investigated for the axle subsystems. The situation when some of the coefficients are known a priori, and also there are certain dependences, possibly nonlinear, among some physical parameters is investigated. Related to this grey box problem, an identification scheme is proposed to obtain the physical parameters from the unconstrained estimates of the abstract parameters of the axle models.

关键词： Vehicles suspension system physical modeling grey box parameter estimation instrumental variable method

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QUALITATIVE MODEL-BASED VERIFICATION OF OPERATING PROCEDURES BY HIGH-LEVEL PETRI NETS

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computerS & CHEMICAL ENGINEERING 1994年第Sup1期18卷 S565-S569页

作者： GERZSON, M CSAKI, Z HANGOS, KM Systems and Control Research Laboratory Computer and Automation Institute Hung. Acad. Sci. H-1518 Budapest P.O. Box 63 Hungary

The presence of colored tokens and time opens the possibility to combine high level Petri nets for describing operating procedures and constraint type qualitative models describing the model of the system over a wide operating range. Places can be associated to state variables and the color of the tokens can be related to the qualitative value of the variable. Are expressions correspond to qualitative model equations. A suitably modified version of the order of magnitude qualitative value representation form is used together with a scaling of each variable to have the same uniform qualitative range. Operations are performed on the interval arithmetic basis and only the result is transformed back to the uniform order of magnitude quantity space. This computation method ensures advantageous algebraic properties. Based on the above idea a novel verification method is proposed in this paper for testing operating procedures against a qualitative model of the system using a high level or colored Petri net representation of the procedure and the model together.

关键词： COLORED PETRI NETS CONSTRAINT TYPE QUALITATIVE MODEL OPERATING PROCEDURES

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