A technical method for constructing smooth solutions for a class of evolution equations is presented. This class of equations includes the Schrodinger equation and the Euler-Bernoulli vibrating plate equation, each with variable coefficients. The work is intended as a tool for boundary control methods which require solution operators with a smoothing effect.<>
{"title":"Boundary control of plates with variable physical characteristics","authors":"S. W. Taylor","doi":"10.1109/CDC.1990.203628","DOIUrl":"https://doi.org/10.1109/CDC.1990.203628","url":null,"abstract":"A technical method for constructing smooth solutions for a class of evolution equations is presented. This class of equations includes the Schrodinger equation and the Euler-Bernoulli vibrating plate equation, each with variable coefficients. The work is intended as a tool for boundary control methods which require solution operators with a smoothing effect.<<ETX>>","PeriodicalId":287089,"journal":{"name":"29th IEEE Conference on Decision and Control","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121497855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The authors present an adaptive high-gain controller which can stabilize minimum-phase nonlinear systems with strong relative degree. The basic structure of the control method is similar to adaptive control methods in the sense that there are two feedback loops. The inner loop is a high-gain feedback loop with a plant and a controller. The controller is completely specified except for a scalar parameter, the high-gain parameter. The controller is designed such that the stabilization of the closed loop will be achieved if the high-gain parameter is chosen large enough. This feature facilitates a simple procedure of tuning the high-gain parameter by increasing it monotonically until it is large enough. The tuning of the parameter is set up by the outer loop. The high-gain parameter is increased in a stepwise fashion so as to follow a continuous-time parameter which is determined by an adaptation rule. The stepwise incrementation plays a crucial role in simplifying the analysis, since between any two switching points the controller is a simple linear time-invariant one.<>
{"title":"Adaptive high-gain stabilization of 'minimum-phase' nonlinear systems","authors":"A. Saberi, Z. Lin","doi":"10.1109/CDC.1990.203433","DOIUrl":"https://doi.org/10.1109/CDC.1990.203433","url":null,"abstract":"The authors present an adaptive high-gain controller which can stabilize minimum-phase nonlinear systems with strong relative degree. The basic structure of the control method is similar to adaptive control methods in the sense that there are two feedback loops. The inner loop is a high-gain feedback loop with a plant and a controller. The controller is completely specified except for a scalar parameter, the high-gain parameter. The controller is designed such that the stabilization of the closed loop will be achieved if the high-gain parameter is chosen large enough. This feature facilitates a simple procedure of tuning the high-gain parameter by increasing it monotonically until it is large enough. The tuning of the parameter is set up by the outer loop. The high-gain parameter is increased in a stepwise fashion so as to follow a continuous-time parameter which is determined by an adaptation rule. The stepwise incrementation plays a crucial role in simplifying the analysis, since between any two switching points the controller is a simple linear time-invariant one.<<ETX>>","PeriodicalId":287089,"journal":{"name":"29th IEEE Conference on Decision and Control","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114695652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three approaches to adaptive control of nonlinear processes using artificial neural networks are presented. They are all based on minimum d-step-ahead prediction error control. All of them are capable of starting at random network weights, and the startup behavior was acceptable. The combination of classical stochastic approximation and the network as an associative memory was superior to more 'neural' approaches. The indirect approach is shown to be a suitable method when used with a recirculation network, making it possible to solve the predictive control with the network itself. The direct approach has a very strong tendency to converge to a local (sometimes unacceptable) minimum.<>
{"title":"Minimum prediction error neural controller","authors":"H. Koivisto","doi":"10.1109/CDC.1990.203919","DOIUrl":"https://doi.org/10.1109/CDC.1990.203919","url":null,"abstract":"Three approaches to adaptive control of nonlinear processes using artificial neural networks are presented. They are all based on minimum d-step-ahead prediction error control. All of them are capable of starting at random network weights, and the startup behavior was acceptable. The combination of classical stochastic approximation and the network as an associative memory was superior to more 'neural' approaches. The indirect approach is shown to be a suitable method when used with a recirculation network, making it possible to solve the predictive control with the network itself. The direct approach has a very strong tendency to converge to a local (sometimes unacceptable) minimum.<<ETX>>","PeriodicalId":287089,"journal":{"name":"29th IEEE Conference on Decision and Control","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114761001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Determination of the steady state response of a system to an input composed of steps, ramps, and various other signals is considered. If the system and/or the input depend on uncertain parameters then a worst-case philosophy dictates that the analysis goal should be to determine the maximum and minimum possible equilibrium values of the output. It is shown that the system is robustly stable and if the dependence on the uncertain parameters is to an extent multiaffine, then the extreme values of the steady state response over the entire set of parameters is equal to the extreme values over just the vertices of the parameter set. This vertex result is doubly useful because it is valid in both continuous-time and discrete-time. For the transient response of stable systems, the vertices do not provide sufficient information for a complete analysis. Examples are presented which show that the maximum overshoot to the step response of a robustly stable uncertain system does not necessarily occur at a vertex. The systems in these examples have an affine dependence on a single uncertain parameter.<>
{"title":"Vertex results for the steady state analysis of uncertain systems","authors":"A. Bartlett","doi":"10.1109/CDC.1990.203637","DOIUrl":"https://doi.org/10.1109/CDC.1990.203637","url":null,"abstract":"Determination of the steady state response of a system to an input composed of steps, ramps, and various other signals is considered. If the system and/or the input depend on uncertain parameters then a worst-case philosophy dictates that the analysis goal should be to determine the maximum and minimum possible equilibrium values of the output. It is shown that the system is robustly stable and if the dependence on the uncertain parameters is to an extent multiaffine, then the extreme values of the steady state response over the entire set of parameters is equal to the extreme values over just the vertices of the parameter set. This vertex result is doubly useful because it is valid in both continuous-time and discrete-time. For the transient response of stable systems, the vertices do not provide sufficient information for a complete analysis. Examples are presented which show that the maximum overshoot to the step response of a robustly stable uncertain system does not necessarily occur at a vertex. The systems in these examples have an affine dependence on a single uncertain parameter.<<ETX>>","PeriodicalId":287089,"journal":{"name":"29th IEEE Conference on Decision and Control","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124300235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. F. Berdaguer, J. Burns, G.H. Piechl, Ricardo Peña
Finite element and other Galerkin approximations often used to construct finite dimensional systems for control design are discussed. These methods produce systems with very special structure and this structure can be exploited in developing computational algorithms. A considerable portion of numerical linear algebra is devoted to numerical methods for systems involving banded, sparse, or block diagonal matrices. However, most numerical algorithms currently used in control design do not take advantage of the special structure that results from approximating infinite dimensional systems by Galerkin models. The authors discuss the problem of computing system radii (e.g., controllability, stabilizability, observability, and detectability margins) for finite element approximations of elastic systems. The simple one dimensional wave equation is used to illustrate the basic ideas.<>
{"title":"A note on computing system radii for Galerkin approximations of elastic systems","authors":"E. F. Berdaguer, J. Burns, G.H. Piechl, Ricardo Peña","doi":"10.1109/CDC.1990.203537","DOIUrl":"https://doi.org/10.1109/CDC.1990.203537","url":null,"abstract":"Finite element and other Galerkin approximations often used to construct finite dimensional systems for control design are discussed. These methods produce systems with very special structure and this structure can be exploited in developing computational algorithms. A considerable portion of numerical linear algebra is devoted to numerical methods for systems involving banded, sparse, or block diagonal matrices. However, most numerical algorithms currently used in control design do not take advantage of the special structure that results from approximating infinite dimensional systems by Galerkin models. The authors discuss the problem of computing system radii (e.g., controllability, stabilizability, observability, and detectability margins) for finite element approximations of elastic systems. The simple one dimensional wave equation is used to illustrate the basic ideas.<<ETX>>","PeriodicalId":287089,"journal":{"name":"29th IEEE Conference on Decision and Control","volume":"119 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124158972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An optimal tracking control of a heat exchanger with load change is considered. It is assumed that the plant is described by a discrete-time state-space model with time-delay, and a direct link between input and output. First, based on the linear quadratic inverse technique, the authors derive an optimal tracking controller having integral, state feedback plus preview actions. To derive a state-space model of a heat exchanger, an ARX model was fitted to the open-loop data obtained from the plant. The properties of the tracking control algorithm are analyzed by simulation studies using the identified model. The optimal control algorithm with an observer was installed on a process computer to provide the set points for the analog PID (proportional plus integral plus derivative) regulators of a heat exchanger plant. Experimental studies show that the control performance of water outlet temperature in the presence of load change is greatly improved.<>
{"title":"Optimal tracking control of a heat exchanger with change in load condition","authors":"T. Katayama, T. Itoh, M. Ogawa, H. Yamamoto","doi":"10.1109/CDC.1990.203880","DOIUrl":"https://doi.org/10.1109/CDC.1990.203880","url":null,"abstract":"An optimal tracking control of a heat exchanger with load change is considered. It is assumed that the plant is described by a discrete-time state-space model with time-delay, and a direct link between input and output. First, based on the linear quadratic inverse technique, the authors derive an optimal tracking controller having integral, state feedback plus preview actions. To derive a state-space model of a heat exchanger, an ARX model was fitted to the open-loop data obtained from the plant. The properties of the tracking control algorithm are analyzed by simulation studies using the identified model. The optimal control algorithm with an observer was installed on a process computer to provide the set points for the analog PID (proportional plus integral plus derivative) regulators of a heat exchanger plant. Experimental studies show that the control performance of water outlet temperature in the presence of load change is greatly improved.<<ETX>>","PeriodicalId":287089,"journal":{"name":"29th IEEE Conference on Decision and Control","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126248095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The authors summarize an approach to the static bifurcation analysis of electric power networks which combines bifurcation theory with proven computational methods and a graphical representation of information which has intuitive appeal. The relationship between contour maps and static bifurcation of power system equilibrium equations is examined. Preliminary results identify the limitations as well as possibilities for enhancement of the generalized circle diagrams introduced by G.B. Price (1984). By combining symbolic and numerical computations this approach appears to be moving toward making power system static bifurcation analysis an intuitive and practical tool for power system operations analysis.<>
{"title":"Computer analysis of static bifurcation in power networks","authors":"H. Kwatny, L. Bahar, X.-M. Yu","doi":"10.1109/CDC.1990.203352","DOIUrl":"https://doi.org/10.1109/CDC.1990.203352","url":null,"abstract":"The authors summarize an approach to the static bifurcation analysis of electric power networks which combines bifurcation theory with proven computational methods and a graphical representation of information which has intuitive appeal. The relationship between contour maps and static bifurcation of power system equilibrium equations is examined. Preliminary results identify the limitations as well as possibilities for enhancement of the generalized circle diagrams introduced by G.B. Price (1984). By combining symbolic and numerical computations this approach appears to be moving toward making power system static bifurcation analysis an intuitive and practical tool for power system operations analysis.<<ETX>>","PeriodicalId":287089,"journal":{"name":"29th IEEE Conference on Decision and Control","volume":"GE-23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126564278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A number of invariance principles for closed, densely defined linear operators are discussed and proved. The first invariance principle establishes an index theorem for closed, densely defined operators under relatively strictly singular perturbation. The second principle, established as a by-product of results on asymptotics, establishes the invariance of the characteristic of property of generating a C/sub 0/-semigroup under a negative spectrum shift by a relatively compact perturbation. The third invariance principle establishes the invariance of the characteristic number of a C/sub 0/-semigroup under a negative spectrum perturbation.<>
{"title":"Index theorems for relatively strictly singular perturbations of infinitesimal generators and their application to stabilizability problems","authors":"G. Knowles","doi":"10.1109/CDC.1990.203624","DOIUrl":"https://doi.org/10.1109/CDC.1990.203624","url":null,"abstract":"A number of invariance principles for closed, densely defined linear operators are discussed and proved. The first invariance principle establishes an index theorem for closed, densely defined operators under relatively strictly singular perturbation. The second principle, established as a by-product of results on asymptotics, establishes the invariance of the characteristic of property of generating a C/sub 0/-semigroup under a negative spectrum shift by a relatively compact perturbation. The third invariance principle establishes the invariance of the characteristic number of a C/sub 0/-semigroup under a negative spectrum perturbation.<<ETX>>","PeriodicalId":287089,"journal":{"name":"29th IEEE Conference on Decision and Control","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121944174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A new philosophy of identification for use in control design is proposed. The current philosophy consists of attempts to find the single best plant model at each time. An example demonstrates the serious problems that may result from using a single model in a control law during the transient phase of identification when this model is not likely to be correct. The new philosophy proposes maintaining a set of possible plant models and eliminating models which are inconsistent with incoming data. The model set should then shrink so that control laws which provide improved performance for the entire model set become possible.<>
{"title":"Rethinking adaptive control for the 1990s","authors":"C. Rohrs","doi":"10.1109/CDC.1990.203406","DOIUrl":"https://doi.org/10.1109/CDC.1990.203406","url":null,"abstract":"A new philosophy of identification for use in control design is proposed. The current philosophy consists of attempts to find the single best plant model at each time. An example demonstrates the serious problems that may result from using a single model in a control law during the transient phase of identification when this model is not likely to be correct. The new philosophy proposes maintaining a set of possible plant models and eliminating models which are inconsistent with incoming data. The model set should then shrink so that control laws which provide improved performance for the entire model set become possible.<<ETX>>","PeriodicalId":287089,"journal":{"name":"29th IEEE Conference on Decision and Control","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127902406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quantization and fusion schemes are derived for multisensor correlation in distributed K-sensor systems that are used for the detection of weak signals or general signal discrimination from dependent observations. Asymptotically optimal memoryless quantization and fusion schemes are derived for problems with dependence in the observations across time and sensors. The results obtained are valid for an arbitrary number of sensors and make it possible to compare the performances of multisensor systems as the number of sensors increases and the correlation in the sensor observations across time and sensors varies. Numerical results based on the simulation of the performance of the proposed schemes with different numbers of sensors are presented. The performance of the optimal nonlinearities and quantizers is shown to be better than that of nonlinearities or quantizers obtained by ignoring the dependence in sensor observations and to improve as the number of sensors increases.<>
{"title":"Multisensor correlation and quantization in distributed detection systems","authors":"Y. Chau, E. Geraniotis","doi":"10.1109/CDC.1990.203265","DOIUrl":"https://doi.org/10.1109/CDC.1990.203265","url":null,"abstract":"Quantization and fusion schemes are derived for multisensor correlation in distributed K-sensor systems that are used for the detection of weak signals or general signal discrimination from dependent observations. Asymptotically optimal memoryless quantization and fusion schemes are derived for problems with dependence in the observations across time and sensors. The results obtained are valid for an arbitrary number of sensors and make it possible to compare the performances of multisensor systems as the number of sensors increases and the correlation in the sensor observations across time and sensors varies. Numerical results based on the simulation of the performance of the proposed schemes with different numbers of sensors are presented. The performance of the optimal nonlinearities and quantizers is shown to be better than that of nonlinearities or quantizers obtained by ignoring the dependence in sensor observations and to improve as the number of sensors increases.<<ETX>>","PeriodicalId":287089,"journal":{"name":"29th IEEE Conference on Decision and Control","volume":"271 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115792085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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