Pub Date : 2014-04-16DOI: 10.1080/21642583.2014.915204
Jun Zhou
By contriving the regularized return difference relationship in linear time-invariant (LTI) feedback systems, we attempt to generalize and validate the Nyquist approach for such internal stability as Lyapunov stability/instability, asymptotic stability, exponential stability and district stability (or -stability), respectively, even when there exist decoupling zeros, by means of what we call the regularized Nyquist loci that are plotted with respect to a Nyquist contour and its conformal one(s). More precisely, miscellaneous open-loop/closed-loop pole cancellations in the return difference relationship that may complicatedly tangle our stability interpretation but usually neglected in most existing Nyquist criteria are scrutinized. And then, Nyquist-like criteria for internal stability are claimed with the regularized Nyquist loci. These criteria get rid of pole cancellations testing and can be implemented completely independent of open-loop pole distribution knowledge; moreover, the Nyquist criteria for asymptotic/exponential stability are necessary and sufficient, while those for -stability are sufficient. Internal stability of a cart system with an inverted pendulum is examined to illustrate the results.
{"title":"Generalizing Nyquist criteria via conformal contours for internal stability analysis","authors":"Jun Zhou","doi":"10.1080/21642583.2014.915204","DOIUrl":"https://doi.org/10.1080/21642583.2014.915204","url":null,"abstract":"By contriving the regularized return difference relationship in linear time-invariant (LTI) feedback systems, we attempt to generalize and validate the Nyquist approach for such internal stability as Lyapunov stability/instability, asymptotic stability, exponential stability and district stability (or -stability), respectively, even when there exist decoupling zeros, by means of what we call the regularized Nyquist loci that are plotted with respect to a Nyquist contour and its conformal one(s). More precisely, miscellaneous open-loop/closed-loop pole cancellations in the return difference relationship that may complicatedly tangle our stability interpretation but usually neglected in most existing Nyquist criteria are scrutinized. And then, Nyquist-like criteria for internal stability are claimed with the regularized Nyquist loci. These criteria get rid of pole cancellations testing and can be implemented completely independent of open-loop pole distribution knowledge; moreover, the Nyquist criteria for asymptotic/exponential stability are necessary and sufficient, while those for -stability are sufficient. Internal stability of a cart system with an inverted pendulum is examined to illustrate the results.","PeriodicalId":22127,"journal":{"name":"Systems Science & Control Engineering: An Open Access Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87145677","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 : 2014-04-10DOI: 10.1080/21642583.2014.913821
F. Harrou, M. Nounou
The evolution of modern wireless communications systems has dramatically increased the demand for antenna arrays. An antenna array with certain radiation characteristics is often desired. However, the actual radiation pattern of an antenna array changes when faults are introduced in the array. In this paper a statistical fault detection methodology based on the exponentially weighted moving average (EWMA) control scheme is proposed to detect possible faulty radiation patterns in linear antenna arrays. The proposed method detects the faults based on deviation in the radiation pattern from the desired ones. The difference between synthesized radiation pattern obtained using the Minimax algorithm and the measured pattern can be used as an indicator about the existence or absence of faults. To assess the fault detection abilities of the EWMA control scheme, three case studies are considered, one involving a complete failure in one element in the array, one involving partial failure in two elements, and one involving degradation caused by random noise due to interference and other factors. The simulation results for all cases show the effectiveness of the proposed EWMA fault detection method.
{"title":"Monitoring linear antenna arrays using an exponentially weighted moving average-based fault detection scheme","authors":"F. Harrou, M. Nounou","doi":"10.1080/21642583.2014.913821","DOIUrl":"https://doi.org/10.1080/21642583.2014.913821","url":null,"abstract":"The evolution of modern wireless communications systems has dramatically increased the demand for antenna arrays. An antenna array with certain radiation characteristics is often desired. However, the actual radiation pattern of an antenna array changes when faults are introduced in the array. In this paper a statistical fault detection methodology based on the exponentially weighted moving average (EWMA) control scheme is proposed to detect possible faulty radiation patterns in linear antenna arrays. The proposed method detects the faults based on deviation in the radiation pattern from the desired ones. The difference between synthesized radiation pattern obtained using the Minimax algorithm and the measured pattern can be used as an indicator about the existence or absence of faults. To assess the fault detection abilities of the EWMA control scheme, three case studies are considered, one involving a complete failure in one element in the array, one involving partial failure in two elements, and one involving degradation caused by random noise due to interference and other factors. The simulation results for all cases show the effectiveness of the proposed EWMA fault detection method.","PeriodicalId":22127,"journal":{"name":"Systems Science & Control Engineering: An Open Access Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74699746","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 : 2014-04-08DOI: 10.1080/21642583.2014.913215
V. Costanza, P. Rivadeneira
A novel approach to approximately solving the restricted-control linear quadratic regulator problem online is substantiated and applied in two case studies. The first example is a one-dimensional system whose exact solution is known. The other one refers to the temperature control of a metallic strip at the exit of a multi-stand rolling mill. The new (online-feedback) strategy employs a convenient version of the gradient method, where partial derivatives of the cost are taken with respect to the final penalization matrix coefficients and to the switching times where the control (de)saturates. The calculations are based on exact algebraic formula, which do not involve trajectory simulations, and so reducing in principle the computational effort associated with receding horizon or nonlinear programming methods.
{"title":"Online suboptimal control of linearized models","authors":"V. Costanza, P. Rivadeneira","doi":"10.1080/21642583.2014.913215","DOIUrl":"https://doi.org/10.1080/21642583.2014.913215","url":null,"abstract":"A novel approach to approximately solving the restricted-control linear quadratic regulator problem online is substantiated and applied in two case studies. The first example is a one-dimensional system whose exact solution is known. The other one refers to the temperature control of a metallic strip at the exit of a multi-stand rolling mill. The new (online-feedback) strategy employs a convenient version of the gradient method, where partial derivatives of the cost are taken with respect to the final penalization matrix coefficients and to the switching times where the control (de)saturates. The calculations are based on exact algebraic formula, which do not involve trajectory simulations, and so reducing in principle the computational effort associated with receding horizon or nonlinear programming methods.","PeriodicalId":22127,"journal":{"name":"Systems Science & Control Engineering: An Open Access Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78674767","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 : 2014-04-08DOI: 10.1080/21642583.2014.912572
Abdelhamid Ouakasse, G. Mélard
Recursive estimation methods for time series models usually make use of recurrences for the vector of parameters, the model error and its derivatives with respect to the parameters, plus a recurrence for the Hessian of the model error. An alternative method is proposed in the case of an autoregressive-moving average model, where the Hessian is not updated but is replaced, at each time, by the inverse of the Fisher information matrix evaluated at the current parameter. The asymptotic properties, consistency and asymptotic normality, of the new estimator are obtained. Monte Carlo experiments indicate that the estimates may converge faster to the true values of the parameters than when the Hessian is updated. The paper is illustrated by an example on forecasting the speed of wind.
{"title":"On-line estimation of ARMA models using Fisher-scoring","authors":"Abdelhamid Ouakasse, G. Mélard","doi":"10.1080/21642583.2014.912572","DOIUrl":"https://doi.org/10.1080/21642583.2014.912572","url":null,"abstract":"Recursive estimation methods for time series models usually make use of recurrences for the vector of parameters, the model error and its derivatives with respect to the parameters, plus a recurrence for the Hessian of the model error. An alternative method is proposed in the case of an autoregressive-moving average model, where the Hessian is not updated but is replaced, at each time, by the inverse of the Fisher information matrix evaluated at the current parameter. The asymptotic properties, consistency and asymptotic normality, of the new estimator are obtained. Monte Carlo experiments indicate that the estimates may converge faster to the true values of the parameters than when the Hessian is updated. The paper is illustrated by an example on forecasting the speed of wind.","PeriodicalId":22127,"journal":{"name":"Systems Science & Control Engineering: An Open Access Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86084795","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 : 2014-04-08DOI: 10.1080/21642583.2014.913214
A. Khandekar, B. Patre
This paper presents the discrete time sliding mode controller for the robust tracking of time-delay systems. In this, an optimal sliding surface is chosen as a linear function of the system-state error and the coefficients of sliding surface are computed by minimizing the quadratic performance index. A delay ahead predictor and corrector is used to handle system's time-delay and plant–model uncertainties. The control law is derived from the discrete time-state model and sliding surface with predicted states for general class of delay-time systems. The methodology integrates optimal sliding surface and delay ahead prediction; and therefore results in optimal performance of the systems. The stability condition is derived using the Lyapunov approach. Simulation examples are included to show the usefulness of the proposed controller.
{"title":"Discrete sliding mode control for robust tracking of time-delay systems","authors":"A. Khandekar, B. Patre","doi":"10.1080/21642583.2014.913214","DOIUrl":"https://doi.org/10.1080/21642583.2014.913214","url":null,"abstract":"This paper presents the discrete time sliding mode controller for the robust tracking of time-delay systems. In this, an optimal sliding surface is chosen as a linear function of the system-state error and the coefficients of sliding surface are computed by minimizing the quadratic performance index. A delay ahead predictor and corrector is used to handle system's time-delay and plant–model uncertainties. The control law is derived from the discrete time-state model and sliding surface with predicted states for general class of delay-time systems. The methodology integrates optimal sliding surface and delay ahead prediction; and therefore results in optimal performance of the systems. The stability condition is derived using the Lyapunov approach. Simulation examples are included to show the usefulness of the proposed controller.","PeriodicalId":22127,"journal":{"name":"Systems Science & Control Engineering: An Open Access Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86121988","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 : 2014-04-07DOI: 10.1080/21642583.2014.912568
Tushar Jain, J. Yamé
In this paper, we present a real-time algorithm for synthesizing an online controller and its implementation in the closed-loop. The novelty of this algorithm lies in the fact that we do not use any a priori knowledge of the model of the plant in real-time. We use the mathematical framework of behavioral theory to demonstrate the online synthesizing and implementation mechanism.
{"title":"On real-time smooth interconnection of online synthesized controllers in the behavioral framework","authors":"Tushar Jain, J. Yamé","doi":"10.1080/21642583.2014.912568","DOIUrl":"https://doi.org/10.1080/21642583.2014.912568","url":null,"abstract":"In this paper, we present a real-time algorithm for synthesizing an online controller and its implementation in the closed-loop. The novelty of this algorithm lies in the fact that we do not use any a priori knowledge of the model of the plant in real-time. We use the mathematical framework of behavioral theory to demonstrate the online synthesizing and implementation mechanism.","PeriodicalId":22127,"journal":{"name":"Systems Science & Control Engineering: An Open Access Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81901600","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 : 2014-04-07DOI: 10.1080/21642583.2014.912570
B. Satpati, C. Koley, S. Datta
This paper presents the design of a robust proportional integral and derivative (PID) controller for a first-order lag with pure delay (FOLPD) model using particle swarm optimization (PSO)-enabled automated quantitative feedback theory (QFT). The plant model considered here can be approximated as a first-order system with a non-minimum phase (NMP) zero. Synthesis of controller for the FOLPD model via manual graphical technique involved in the QFT method is always a challenging and cumbersome task, because an NMP system stabilizes by a small gain. In this paper, a proposal is being presented to automate the loop-shaping phase in the QFT design method to synthesize a robust controller that can undertake the exact amount of plant uncertainty even in the presence of larger uncertainties than those assumed initially and can ensure a proper trade-off between robust stability and tracking performance specifications over the entire range of design frequencies. In this paper,s the PSO technique has been employed to tune the controller automatically,which can significantly reduce the computational effort compared with manual graphical techniques. It has also been demonstrated that this methodology not only automates loop shaping but also improves design quality and, most usefully, improves performance with optimally tuned PID controller in quantitative manner.
{"title":"Robust PID controller design using particle swarm optimization-enabled automated quantitative feedback theory approach for a first-order lag system with minimal dead time","authors":"B. Satpati, C. Koley, S. Datta","doi":"10.1080/21642583.2014.912570","DOIUrl":"https://doi.org/10.1080/21642583.2014.912570","url":null,"abstract":"This paper presents the design of a robust proportional integral and derivative (PID) controller for a first-order lag with pure delay (FOLPD) model using particle swarm optimization (PSO)-enabled automated quantitative feedback theory (QFT). The plant model considered here can be approximated as a first-order system with a non-minimum phase (NMP) zero. Synthesis of controller for the FOLPD model via manual graphical technique involved in the QFT method is always a challenging and cumbersome task, because an NMP system stabilizes by a small gain. In this paper, a proposal is being presented to automate the loop-shaping phase in the QFT design method to synthesize a robust controller that can undertake the exact amount of plant uncertainty even in the presence of larger uncertainties than those assumed initially and can ensure a proper trade-off between robust stability and tracking performance specifications over the entire range of design frequencies. In this paper,s the PSO technique has been employed to tune the controller automatically,which can significantly reduce the computational effort compared with manual graphical techniques. It has also been demonstrated that this methodology not only automates loop shaping but also improves design quality and, most usefully, improves performance with optimally tuned PID controller in quantitative manner.","PeriodicalId":22127,"journal":{"name":"Systems Science & Control Engineering: An Open Access Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84932479","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 : 2014-03-31DOI: 10.1080/21642583.2014.900729
Neng-Hui Shih, Chih-Hsiung Wang
Consider an input material with a nonconforming probability that is used for the production of a product through a deteriorating process, which is initially maintained in an in-control state, but can randomly shift into an out-of-control state after some products are produced. To economically control the total quality-related cost for a given production lot, an optimal inspection policy for the products and their input materials is proposed. Furthermore, under the optimal inspection policy, a decision on the optimal production lot size is also incorporated. The unique properties and conditions that give the optimal production lot size are explored. Numerical examples are given to illustrate our proposed inspection and production model. The effects of the model's parameter values, such as inspection error rate, unit inspection cost for the input material, unit inspection cost for the product, etc., on the optimal solution are investigated. Finally, some useful insights that should help industrial operations are presented.
{"title":"An inspection model of products and their input materials","authors":"Neng-Hui Shih, Chih-Hsiung Wang","doi":"10.1080/21642583.2014.900729","DOIUrl":"https://doi.org/10.1080/21642583.2014.900729","url":null,"abstract":"Consider an input material with a nonconforming probability that is used for the production of a product through a deteriorating process, which is initially maintained in an in-control state, but can randomly shift into an out-of-control state after some products are produced. To economically control the total quality-related cost for a given production lot, an optimal inspection policy for the products and their input materials is proposed. Furthermore, under the optimal inspection policy, a decision on the optimal production lot size is also incorporated. The unique properties and conditions that give the optimal production lot size are explored. Numerical examples are given to illustrate our proposed inspection and production model. The effects of the model's parameter values, such as inspection error rate, unit inspection cost for the input material, unit inspection cost for the product, etc., on the optimal solution are investigated. Finally, some useful insights that should help industrial operations are presented.","PeriodicalId":22127,"journal":{"name":"Systems Science & Control Engineering: An Open Access Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85919092","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 : 2014-03-31DOI: 10.1080/21642583.2014.897657
E. Borgatti, U. Viaro
The paper proposes a simple feedback model capable of explaining the evolution of various civilizations as determined by historians and scientists. The forward path of this feedback model consists of a first-order system, accounting for an accumulation process, in series with a pure time delay, and its feedback path consists of a constant possibly preceded by a filter. To account for an eventual decline, a smoothed derivative term can also be added. It is shown how the evolution pattern depends on few model parameters susceptible to interesting interpretations, thus providing a powerful “tool for thought”. The relation of the suggested model with the Phillips model of a closed economy is also pointed out.
{"title":"A feedback model for the evolution of civilizations","authors":"E. Borgatti, U. Viaro","doi":"10.1080/21642583.2014.897657","DOIUrl":"https://doi.org/10.1080/21642583.2014.897657","url":null,"abstract":"The paper proposes a simple feedback model capable of explaining the evolution of various civilizations as determined by historians and scientists. The forward path of this feedback model consists of a first-order system, accounting for an accumulation process, in series with a pure time delay, and its feedback path consists of a constant possibly preceded by a filter. To account for an eventual decline, a smoothed derivative term can also be added. It is shown how the evolution pattern depends on few model parameters susceptible to interesting interpretations, thus providing a powerful “tool for thought”. The relation of the suggested model with the Phillips model of a closed economy is also pointed out.","PeriodicalId":22127,"journal":{"name":"Systems Science & Control Engineering: An Open Access Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90931086","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 : 2014-03-27DOI: 10.1080/21642583.2014.897658
Qingling Wang, Huijun Gao, F. Alsaadi, T. Hayat
In recent years, multi-agent coordination has gained significant development in theoretical research in parallel with the increasing attention in the practical applications of such systems in various areas including consensus. This paper presents a survey of recent research in consensus problems for constrained multi-agent coordination. We first focus on theoretical directions of multi-agent systems paying particular attention from the system dynamics and control algorithms perspective. Then we present several problems on constrained multi-agent coordination via consensus schemes which have gained significant attention recently. Relevant to these problems, we summarize some of the recent results on constrained multi-agent coordination via consensus schemes which appeared in the literature. Finally, this paper is concluded with existing results and some remarks on the practical direction of consensus problems developed for constrained multi-agent coordination.
{"title":"An overview of consensus problems in constrained multi-agent coordination","authors":"Qingling Wang, Huijun Gao, F. Alsaadi, T. Hayat","doi":"10.1080/21642583.2014.897658","DOIUrl":"https://doi.org/10.1080/21642583.2014.897658","url":null,"abstract":"In recent years, multi-agent coordination has gained significant development in theoretical research in parallel with the increasing attention in the practical applications of such systems in various areas including consensus. This paper presents a survey of recent research in consensus problems for constrained multi-agent coordination. We first focus on theoretical directions of multi-agent systems paying particular attention from the system dynamics and control algorithms perspective. Then we present several problems on constrained multi-agent coordination via consensus schemes which have gained significant attention recently. Relevant to these problems, we summarize some of the recent results on constrained multi-agent coordination via consensus schemes which appeared in the literature. Finally, this paper is concluded with existing results and some remarks on the practical direction of consensus problems developed for constrained multi-agent coordination.","PeriodicalId":22127,"journal":{"name":"Systems Science & Control Engineering: An Open Access Journal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80271019","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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