{"title":"Policy iteration for H∞ control of polynomial time-varying systems","authors":"Sajjad Pakkhesal, Saeed Shamaghdari","doi":"10.1049/cth2.12661","DOIUrl":null,"url":null,"abstract":"<p>This paper studies the <i>H<sub>∞</sub></i> control problem for polynomial time-varying systems. The <i>H<sub>∞</sub></i> control problem has been much less investigated for time-varying systems in comparison to the time-invariant systems. Approximate dynamic programming (ADP) is an optimal method to solve the control problems. Therefore, it is valuable to solve the polynomial time-varying <i>H<sub>∞</sub></i> control problem with the ADP approach. Considering the time as an independent variable for sum-of-squares (SOS) optimization problems, an SOS-based ADP method is proposed to solve this problem. A policy iteration algorithm is presented, where in its policy evaluation step it is sufficient to solve an optimization problem. Some constraints are added to this optimization problem to guarantee the closed-loop exponential stability. The convergence and stability properties of the proposed algorithm are stated and proven. Moreover, in order to design an <i>H<sub>∞</sub></i> controller with a smaller disturbance attenuation coefficient, a two-loop algorithm is suggested. Finally, the effectiveness of the proposed method is demonstrated by simulation examples.</p>","PeriodicalId":50382,"journal":{"name":"IET Control Theory and Applications","volume":"18 10","pages":"1248-1261"},"PeriodicalIF":2.2000,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/cth2.12661","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IET Control Theory and Applications","FirstCategoryId":"94","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1049/cth2.12661","RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"AUTOMATION & CONTROL SYSTEMS","Score":null,"Total":0}
引用次数: 0
Abstract
This paper studies the H∞ control problem for polynomial time-varying systems. The H∞ control problem has been much less investigated for time-varying systems in comparison to the time-invariant systems. Approximate dynamic programming (ADP) is an optimal method to solve the control problems. Therefore, it is valuable to solve the polynomial time-varying H∞ control problem with the ADP approach. Considering the time as an independent variable for sum-of-squares (SOS) optimization problems, an SOS-based ADP method is proposed to solve this problem. A policy iteration algorithm is presented, where in its policy evaluation step it is sufficient to solve an optimization problem. Some constraints are added to this optimization problem to guarantee the closed-loop exponential stability. The convergence and stability properties of the proposed algorithm are stated and proven. Moreover, in order to design an H∞ controller with a smaller disturbance attenuation coefficient, a two-loop algorithm is suggested. Finally, the effectiveness of the proposed method is demonstrated by simulation examples.
期刊介绍:
IET Control Theory & Applications is devoted to control systems in the broadest sense, covering new theoretical results and the applications of new and established control methods. Among the topics of interest are system modelling, identification and simulation, the analysis and design of control systems (including computer-aided design), and practical implementation. The scope encompasses technological, economic, physiological (biomedical) and other systems, including man-machine interfaces.
Most of the papers published deal with original work from industrial and government laboratories and universities, but subject reviews and tutorial expositions of current methods are welcomed. Correspondence discussing published papers is also welcomed.
Applications papers need not necessarily involve new theory. Papers which describe new realisations of established methods, or control techniques applied in a novel situation, or practical studies which compare various designs, would be of interest. Of particular value are theoretical papers which discuss the applicability of new work or applications which engender new theoretical applications.