Pub Date : 1988-06-15DOI: 10.23919/ACC.1988.4789899
Y. Mohamed, L. Liu, M. Elbestawi
A stochastic self-tuning controller is implemented to regulate the cutting forces in end milling under varying cutting conditions. A microprocessor controlled NC milling machine is used in this study. The force controller is implemented using another microcomputer system interfaced with the CNC milling machine. Both the linear and nonlinear characteristics of the cutting forces are examined. A deadbeat controller is then used for force regulation. The proposed controller is shown using simulation and experimental resul ts to be stable with good performance characteristics over a wide range of operating conditions.
{"title":"Stochastic Self-Tuning Control of Cutting Forces in a CNC Machine Tool","authors":"Y. Mohamed, L. Liu, M. Elbestawi","doi":"10.23919/ACC.1988.4789899","DOIUrl":"https://doi.org/10.23919/ACC.1988.4789899","url":null,"abstract":"A stochastic self-tuning controller is implemented to regulate the cutting forces in end milling under varying cutting conditions. A microprocessor controlled NC milling machine is used in this study. The force controller is implemented using another microcomputer system interfaced with the CNC milling machine. Both the linear and nonlinear characteristics of the cutting forces are examined. A deadbeat controller is then used for force regulation. The proposed controller is shown using simulation and experimental resul ts to be stable with good performance characteristics over a wide range of operating conditions.","PeriodicalId":6395,"journal":{"name":"1988 American Control Conference","volume":"1 1","pages":"1178-1183"},"PeriodicalIF":0.0,"publicationDate":"1988-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79916088","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}
Pub Date : 1988-06-15DOI: 10.23919/ACC.1988.4789694
E. Parsons
The problem of control/structural interaction arises in ground and space systems where flexibility limits performance. In this paper, an experiment called the "jitter beam" simulates the interaction of a pointing control system and a flexible structure. Noncolocation of a sensor and an actuator makes control difficult. A Linear Quadratic Gaussian (LQG) design overcomes the noncolocation problem by use of a bending model. The capability to deal with noncolocation enables the jitter-beam control to coordinate, with a single torquer, the motions of several points on the structure to achieve the pointing goal. The significant achievement of the experiment is the practical demonstration of a control bandwidth two times higher than a critical bending frequency, a factor of ten beyond what a rigid-body design can achieve. The jitter beam experiment resembles small stiff structures like active mirrors. Although the experiment is small and simple, the control methodology can be extended in principle to large structures and complex systems like segmented mirrors. The sparse model frequency spectrum of stiff structures simplifies identification, but because bending frequencies are high, sensor noise, actuator saturation, and computational speed constrain performance. In contrast, the low frequencies of large structures make hardware constraints a small concern, but the dense frequency distribution complicates system identification.
{"title":"The Jitter Beam: An Experiment Demonstrating Pointing Control on a Flexible Structure","authors":"E. Parsons","doi":"10.23919/ACC.1988.4789694","DOIUrl":"https://doi.org/10.23919/ACC.1988.4789694","url":null,"abstract":"The problem of control/structural interaction arises in ground and space systems where flexibility limits performance. In this paper, an experiment called the \"jitter beam\" simulates the interaction of a pointing control system and a flexible structure. Noncolocation of a sensor and an actuator makes control difficult. A Linear Quadratic Gaussian (LQG) design overcomes the noncolocation problem by use of a bending model. The capability to deal with noncolocation enables the jitter-beam control to coordinate, with a single torquer, the motions of several points on the structure to achieve the pointing goal. The significant achievement of the experiment is the practical demonstration of a control bandwidth two times higher than a critical bending frequency, a factor of ten beyond what a rigid-body design can achieve. The jitter beam experiment resembles small stiff structures like active mirrors. Although the experiment is small and simple, the control methodology can be extended in principle to large structures and complex systems like segmented mirrors. The sparse model frequency spectrum of stiff structures simplifies identification, but because bending frequencies are high, sensor noise, actuator saturation, and computational speed constrain performance. In contrast, the low frequencies of large structures make hardware constraints a small concern, but the dense frequency distribution complicates system identification.","PeriodicalId":6395,"journal":{"name":"1988 American Control Conference","volume":"105 1","pages":"61-68"},"PeriodicalIF":0.0,"publicationDate":"1988-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88198842","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}
Pub Date : 1988-06-15DOI: 10.23919/ACC.1988.4789851
T. Sugie, K. Osuka, T. Ono
This paper proposes a robust control law which achieves desired command response with prescribed accuracy for uncertain nonlinear robot manipulators. The distinguish feature of our method is that (i) tracking accuracy, (ii) desired command response, and (iii) desired initial error response can be achieved simultaneously without the precise knowledge of manipulator dynamics.
{"title":"Two-Stage Robust Model Following Control for Robot Manipulators","authors":"T. Sugie, K. Osuka, T. Ono","doi":"10.23919/ACC.1988.4789851","DOIUrl":"https://doi.org/10.23919/ACC.1988.4789851","url":null,"abstract":"This paper proposes a robust control law which achieves desired command response with prescribed accuracy for uncertain nonlinear robot manipulators. The distinguish feature of our method is that (i) tracking accuracy, (ii) desired command response, and (iii) desired initial error response can be achieved simultaneously without the precise knowledge of manipulator dynamics.","PeriodicalId":6395,"journal":{"name":"1988 American Control Conference","volume":"6 1","pages":"898-903"},"PeriodicalIF":0.0,"publicationDate":"1988-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88282510","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}
Pub Date : 1988-06-15DOI: 10.23919/ACC.1988.4790139
T. Djaferis, C. Hollot
The paper considers stability issues for linear, time-invariant, single-input, multi-output systems which are affected by parametric uncertainty. Our objective is to completely characterize in parameter space, the stability region of a system for a given feedback compensator that stabilizes the nominal part. It is shown that in the case when parameters affect the closed loop characteristic polynomial in a linear manner, this region is the intersection of two sets. One is generated by a finite number of linear constraints. The other in general has a nonlinear boundary (in parameter space) which can be expressed as a function of frequency. It is also shown that if certain shaping conditions are satisfied the stability region is generated solely by a finite number of linear constraints.
{"title":"Characterization of the Hurwitz Region for Systems with Parametric Uncertainty","authors":"T. Djaferis, C. Hollot","doi":"10.23919/ACC.1988.4790139","DOIUrl":"https://doi.org/10.23919/ACC.1988.4790139","url":null,"abstract":"The paper considers stability issues for linear, time-invariant, single-input, multi-output systems which are affected by parametric uncertainty. Our objective is to completely characterize in parameter space, the stability region of a system for a given feedback compensator that stabilizes the nominal part. It is shown that in the case when parameters affect the closed loop characteristic polynomial in a linear manner, this region is the intersection of two sets. One is generated by a finite number of linear constraints. The other in general has a nonlinear boundary (in parameter space) which can be expressed as a function of frequency. It is also shown that if certain shaping conditions are satisfied the stability region is generated solely by a finite number of linear constraints.","PeriodicalId":6395,"journal":{"name":"1988 American Control Conference","volume":"42 1","pages":"2465-2470"},"PeriodicalIF":0.0,"publicationDate":"1988-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88597814","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}
Pub Date : 1988-06-15DOI: 10.1109/ACC.1988.4172716
T. Dwyer, J. Wade
Boresight disturbances during the operation of an electromagnetic rail gun considered herein arise from the coupling of the structural dynamics of the conducting rails with the electrodynamics of the plasma and rail currents. A simplified model of a rail gun is used here to size these effects on pointing accuracy, for purposes of fire control.
{"title":"Boresight Disturbance Modeling of a Space-Based Electromagnetic Rail Gun","authors":"T. Dwyer, J. Wade","doi":"10.1109/ACC.1988.4172716","DOIUrl":"https://doi.org/10.1109/ACC.1988.4172716","url":null,"abstract":"Boresight disturbances during the operation of an electromagnetic rail gun considered herein arise from the coupling of the structural dynamics of the conducting rails with the electrodynamics of the plasma and rail currents. A simplified model of a rail gun is used here to size these effects on pointing accuracy, for purposes of fire control.","PeriodicalId":6395,"journal":{"name":"1988 American Control Conference","volume":"594 1","pages":"55-60"},"PeriodicalIF":0.0,"publicationDate":"1988-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77305354","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}
Pub Date : 1988-06-15DOI: 10.1109/ACC.1988.4173106
J. Balchen, D. Ljungquist, S. Strand
Repetitive online computation of the control vector by solving the optimal control problem of a non-linear multivariable process with arbitrary performance indices is investigated. Two different methods are considered in the search for an optimal, parameterized control vector: Pontryagin's Maximum Principle and optimization by using the performance index and its gradient directly. Unfortunately, solving this optimization problem has turned out to be a rather time-consuming task which has resulted in a time delay that cannot be accepted when the actual process is exposed to rapidly-varying disturbances. However, an instantaneous feedback strategy operating in parallel with the original control algorithm was found to be able to cope with this problem.
{"title":"Predictive Control based upon State Space Models","authors":"J. Balchen, D. Ljungquist, S. Strand","doi":"10.1109/ACC.1988.4173106","DOIUrl":"https://doi.org/10.1109/ACC.1988.4173106","url":null,"abstract":"Repetitive online computation of the control vector by solving the optimal control problem of a non-linear multivariable process with arbitrary performance indices is investigated. Two different methods are considered in the search for an optimal, parameterized control vector: Pontryagin's Maximum Principle and optimization by using the performance index and its gradient directly. Unfortunately, solving this optimization problem has turned out to be a rather time-consuming task which has resulted in a time delay that cannot be accepted when the actual process is exposed to rapidly-varying disturbances. However, an instantaneous feedback strategy operating in parallel with the original control algorithm was found to be able to cope with this problem.","PeriodicalId":6395,"journal":{"name":"1988 American Control Conference","volume":"80 1","pages":"2174-2179"},"PeriodicalIF":0.0,"publicationDate":"1988-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77367163","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}
Pub Date : 1988-06-15DOI: 10.23919/ACC.1988.4789848
J. Raptis, M. Sawan
In this paper, a method is proposed for the design of linear, multivariable, discrete-time controllers with the following characteristics: 1. Constant-gain, minimal order observer - based control laws, 2. n-step, dead beat characteristics, 3. Reduced sensitivity to small system parameter variations.
{"title":"Observer based, Dead-Beat Controller with Reduced Sensitivity","authors":"J. Raptis, M. Sawan","doi":"10.23919/ACC.1988.4789848","DOIUrl":"https://doi.org/10.23919/ACC.1988.4789848","url":null,"abstract":"In this paper, a method is proposed for the design of linear, multivariable, discrete-time controllers with the following characteristics: 1. Constant-gain, minimal order observer - based control laws, 2. n-step, dead beat characteristics, 3. Reduced sensitivity to small system parameter variations.","PeriodicalId":6395,"journal":{"name":"1988 American Control Conference","volume":"31 1","pages":"888-889"},"PeriodicalIF":0.0,"publicationDate":"1988-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77549184","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}
Pub Date : 1988-06-15DOI: 10.1109/ACC.1988.4172883
G. E. Young, J. J. Shelton, C. Kardamilas
Web processing systems rely on accurate lateral positioning to achieve high processing speeds and improved product quality. Due to physical constraints in some processing lines placement of the edge sensor near the web guide is not possible. As a result, large lateral oscillations and/or web instability have been observed. A new model is developed for lateral web dynamics. Experimental verification has justified the structure of the model. A parameter estimation scheme is used to tune the model for imperfections not originally incorporated. State estimation is then used to predict lateral web position based on a downstream sensor. Desirable control is achieved and is further improved with the use of a feedforward sensor. Predicted and experimental results are compared.
{"title":"Modeling and Control of Multiple Web Spans using State Estimation","authors":"G. E. Young, J. J. Shelton, C. Kardamilas","doi":"10.1109/ACC.1988.4172883","DOIUrl":"https://doi.org/10.1109/ACC.1988.4172883","url":null,"abstract":"Web processing systems rely on accurate lateral positioning to achieve high processing speeds and improved product quality. Due to physical constraints in some processing lines placement of the edge sensor near the web guide is not possible. As a result, large lateral oscillations and/or web instability have been observed. A new model is developed for lateral web dynamics. Experimental verification has justified the structure of the model. A parameter estimation scheme is used to tune the model for imperfections not originally incorporated. State estimation is then used to predict lateral web position based on a downstream sensor. Desirable control is achieved and is further improved with the use of a feedforward sensor. Predicted and experimental results are compared.","PeriodicalId":6395,"journal":{"name":"1988 American Control Conference","volume":"17 1","pages":"956-962"},"PeriodicalIF":0.0,"publicationDate":"1988-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87170000","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}
Pub Date : 1988-06-15DOI: 10.23919/ACC.1988.4789807
J. Dimitratos, C. Georgakis, M. El-Aasser, A. Klein
Composition control of the sub-micron latex particles in the semicontinuous emulsion copolymerization of vinyl acetate / n-butyl acrylate is investigated. A stochastic approach is employed to compensate for modeling inaccuracies and measurement errors and an adaptive Kalman filter is used to estimate simultaneously the process states and the statistics of the noise vectors. A combined feedforward/feedback controller is derived to maintain constant copolymer composition in the latex particles. The controller operates on the Kalman filter estimates and manipulates the monomer addition rates to the polymer reactor.
{"title":"Composition Control and Kalman Filtering in Emulsion Copolymerization","authors":"J. Dimitratos, C. Georgakis, M. El-Aasser, A. Klein","doi":"10.23919/ACC.1988.4789807","DOIUrl":"https://doi.org/10.23919/ACC.1988.4789807","url":null,"abstract":"Composition control of the sub-micron latex particles in the semicontinuous emulsion copolymerization of vinyl acetate / n-butyl acrylate is investigated. A stochastic approach is employed to compensate for modeling inaccuracies and measurement errors and an adaptive Kalman filter is used to estimate simultaneously the process states and the statistics of the noise vectors. A combined feedforward/feedback controller is derived to maintain constant copolymer composition in the latex particles. The controller operates on the Kalman filter estimates and manipulates the monomer addition rates to the polymer reactor.","PeriodicalId":6395,"journal":{"name":"1988 American Control Conference","volume":"15 1","pages":"689-694"},"PeriodicalIF":0.0,"publicationDate":"1988-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87563116","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}
Pub Date : 1988-06-15DOI: 10.23919/ACC.1988.4789744
David G. Taylor, P. Kokotovic, R. Marino, I. Kanellakopoulos
Conditions are given for global stability of an adaptive control law designed for the reduced order model of a class of higher order nonlinear plants. In the presence of unmodeled dynamics. which account for the difference between the model and the plant, the regulation property is preserved in a stability region. The size of the region is estimated via a set of bounds that not only proves robustness, but also allows a comparison between adaptive and nonadaptive nonlinear controls.
{"title":"Adaptive Regulation of Nonlinear Systems with Unmodeled Dynamics","authors":"David G. Taylor, P. Kokotovic, R. Marino, I. Kanellakopoulos","doi":"10.23919/ACC.1988.4789744","DOIUrl":"https://doi.org/10.23919/ACC.1988.4789744","url":null,"abstract":"Conditions are given for global stability of an adaptive control law designed for the reduced order model of a class of higher order nonlinear plants. In the presence of unmodeled dynamics. which account for the difference between the model and the plant, the regulation property is preserved in a stability region. The size of the region is estimated via a set of bounds that not only proves robustness, but also allows a comparison between adaptive and nonadaptive nonlinear controls.","PeriodicalId":6395,"journal":{"name":"1988 American Control Conference","volume":"114 1","pages":"360-365"},"PeriodicalIF":0.0,"publicationDate":"1988-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87619330","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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