The decentralized robust control of a completely general servomechanism problem is considered in this paper. Necessary and sufficient conditions, together with a characterization of all decentralized robust controller...
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The decentralized robust control of a completely general servomechanism problem is considered in this paper. Necessary and sufficient conditions, together with a characterization of all decentralized robust controllers which enables asymptotic tracking to occur, independent of disturbances in the plant and perturbations in the plant parameters and gains of the system, is obtained. A new type of compensator called a decentralized servo-compensator which is quite distinct from an observer is introduced. It is shown that this compensator, which corresponds to an integral controller in classical control theory, must be used in any decentralized servomechanism problem to assure that the controlled system is stablizable and achieves robust control; in particular, it is shown that a decentralized robust controller of a general servomechanism problem consists of two devices (i) a decentralized servo-compensator and (ii) a decentralized stabilizing compensator. It is then shown that, under certain mild conditions, there almost always is a solution to the robust decentralized servomechanism problem for any composite system consisting of a number of subsystems interconnected in any arbitrary manner. This last observation has important implications for processcontrol.
Two processes are termed strongly (respectively weakly) feedback free when the canonical innovations representation (IR) of the joint process has one of two specified structures respectively [1-4]. The property that t...
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Two processes are termed strongly (respectively weakly) feedback free when the canonical innovations representation (IR) of the joint process has one of two specified structures respectively [1-4]. The property that two processes are feed-back free captures the notion of a unique direction of influence between two processes. A set of equivalent characterizations of this property is presented in this paper. These characterizations yield a set of statistical tests for feed-back. When feedback exists between two processes it is possible to identify the separate loops of the IR by prediction error methods [5-9]. However, it is only when the disturbances in each loop are mutually orthogonal, and one of the loops contains a delay, that the loops so identified constitute the feedforward and feedback loops of the observed physical system. In this paper we describe how closed loop identification problems arise in load and generating source identification in power systems. We present some initial simulation results obtained by applying a spectral factorization algorithm to the problem of closed loop system identification. Further, we describe the application of this algorithm to real power system data [18-20].
This paper will describe an adaptive control system for aircraft that is based on a parameter identification on-line scheme. The adaptive mechanism uses two elements: one, a digital batch processing of a data record t...
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This paper will describe an adaptive control system for aircraft that is based on a parameter identification on-line scheme. The adaptive mechanism uses two elements: one, a digital batch processing of a data record to obtain identified parameters; and, two, algebraic relations specifying the control law constants given the identified parameters. Concerning the first, a data record representing a time history of the most recent state measurements serves as the input to a computational algorithm for the identifier. It has a finite length and, hence, as new measurements are taken, old ones are pushed out of the data batch. The computational algorithm used to identify the parameters is a modified Newton-Raphson scheme. It uses a linearized model to represent vehicle motions. The model is obtained from continuous-time representations of the aircraft dynamics. The continuous-time representation is converted to a discrete form necessary for the model using a first-order Euler integration scheme. The model contains 10 parameters which are to be identified. Three parameters relate to the longitudinal motions of the vehicle and the remaining ones relate to the vehicle's lateral motions. The longitudinal and lateral model parameters affect only longitudinal and lateral model variables, respectively. This permits identification of longitudinal or lateral parameters as subsets when the data record does not contain adequate information for complete identification of all subsets of the model parameter space. Parameter subsets are altered only after a successful test of the rank of the information matrix related to that subset. The second element involves taking the parameter estimates and adjusting control law constants. That operation should be performed only after the process is converged to proper estimates of the parameters. Hence, another test (related to smallness of the model fit error over the data batch) is made to insure that the parameter estimates are meaningful. The
Forrester's Urban dynamics and the criticism which it received provide a set of axioms which should guide the second generation of urban model builders. An urban model currently under development which follows the...
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Forrester's Urban dynamics and the criticism which it received provide a set of axioms which should guide the second generation of urban model builders. An urban model currently under development which follows these axioms is outlined, and a detailed description of the sector of that model dealing with the educational process is presented.
This volume contains 44 papers presented at the Third Contact Mechanics International symposium (CMIS 2001) held in Praia da Consola9ao, Peniche (portugal), June 17-21,2001. This symposium was the direct continuation ...
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ISBN:
(数字)9789401711548
ISBN:
(纸本)9781402008115;9789048160990
This volume contains 44 papers presented at the Third Contact Mechanics International symposium (CMIS 2001) held in Praia da Consola9ao, Peniche (portugal), June 17-21,2001. This symposium was the direct continuation of the first two CMIS held in Lausanne (1992) and in Carry-Le-Rouet (1994). Other related meetings, in what concerns scientific topics and participants, took place in the nineties at La Grande Motte (1990), Vadstena (1996), Ferrara (1997), Munich (1998) and Grenoble (1999). The symposium aimed at gathering researchers with interests in a wide range of topics in theoretical, computational and experimental contact mechanics. The call for papers mentioned topics in tribology, mathematical formulations and analysis, numerical methods in non-smooth mechanics, impact problems, instabilities and technological problems. The total number of participants was 102, from Universities and Research Institutes of 19 countries. The Scientific Committee reviewed 102 submitted abstracts, and the final program consisted of 6 main lectures, 43 oral communications and 36 poster presentations (see Appendix A). The papers in this book correspond to almost all the main lectures and oral communications, and they are assembled in 5 chapters: • dynamics and Impact • Instabilities, Oscillations and Waves • Contact Models, Results and Applications • Mathematical Analysis • Numerical Methods. We thank all the authors for their valuable contributions to this volume. We are indebted to the members of the Scientific Committee for their help in refereeing the submitted abstracts and manuscripts. We also thank the Series editor, Prof. Graham Gladwell, for his assistance in the revision process.
The formulation of a parameter adaptive control problem is discussed in which a reference model with adjustable structure is updated along with the controller parameters in order to be assured that the performance ind...
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Nature of control is examined to develop philosophy for solving control problems of chemical processes;general areas are outlined in which special freedoms and restraints in design of control loops for pilot plants ca...
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Nature of control is examined to develop philosophy for solving control problems of chemical processes;general areas are outlined in which special freedoms and restraints in design of control loops for pilot plants can be found;role of systems engineer in process design is discussed and how he may work most effectively with process problems.
A method called dynamic modeling is used to obtain near optimal closed-loop control laws for a fixed-time pursuit-evasion differential game between two aircraft in a vertical plane. This dynamic modeling technique inv...
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