{"title":"Stochastic linear–quadratic control problems with affine constraints","authors":"","doi":"10.1016/j.sysconle.2024.105887","DOIUrl":"10.1016/j.sysconle.2024.105887","url":null,"abstract":"<div><p>This paper investigates the stochastic linear–quadratic control problems with affine constraints, in which both equality and inequality constraints are involved. With the help of the Pontryagin maximum principle and Lagrangian duality theory, both the dual problem and the state feedback form of the solution are obtained for the primal problem. Under the Slater condition, the strong duality is proved between the dual problem and the primal problem, and the KKT condition is also provided for solving the primal problem. Moreover, a new sufficient condition is given for the invertibility assumption, which ensures the uniqueness of the solutions to the dual problem. Finally, two numerical examples are provided to illustrate our main results.</p></div>","PeriodicalId":49450,"journal":{"name":"Systems & Control Letters","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On sufficient and necessary conditions of compositional input-to-state safety for nonlinear systems","authors":"","doi":"10.1016/j.sysconle.2024.105886","DOIUrl":"10.1016/j.sysconle.2024.105886","url":null,"abstract":"<div><p>This paper is concerned with studying the problem of compositional input-to-state safety (ISSf) using input-to-state safe barrier functions (ISSf-BFs) for nonlinear systems given as an interconnection of subsystems. A sufficient condition is proposed to verify ISSf for nonlinear interconnected systems, which allows that only some subsystems are ISSf and the others are not. The idea behind the sufficient condition is to establish ISSf of nonlinear interconnected systems based on ISSf of some lower dimensional subsystems, in conjunction with a general type of interconnection between subsystems. Also, a necessary condition is derived by using additively separable ISSf-BFs, which provides a tool for analyzing ISSf of interconnected subsystems. Meanwhile, the necessary condition indicates that the ISSf problem of the overall nonlinear system can be divided into decoupled subproblems, which is dealt with less computational effort. In particular, a sufficient and necessary condition of compositional ISSf is obtained. Finally, three examples are presented to demonstrate the effectiveness of the theoretical results.</p></div>","PeriodicalId":49450,"journal":{"name":"Systems & Control Letters","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Resilient distributed averaging: Adversary detection and topological insights","authors":"","doi":"10.1016/j.sysconle.2024.105844","DOIUrl":"10.1016/j.sysconle.2024.105844","url":null,"abstract":"<div><p>In this paper, a distributed averaging algorithm in the presence of adversarial Byzantine agents is proposed. The algorithm is based on a resilient retrieval procedure, where all non-Byzantine nodes send their own initial values and retrieve those of other agents. We establish that the convergence of the proposed algorithm relies on <em>strong robustness</em> of the graph for locally bounded adversaries in a network with communication delays and asynchrony. A topology analysis in terms of time complexity and relation between connectivity metrics is also presented. Simulation results are provided to verify the effectiveness of the proposed algorithms under prescribed graph conditions.</p></div>","PeriodicalId":49450,"journal":{"name":"Systems & Control Letters","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mercer kernel absolute integrability is only sufficient for RKHS stability","authors":"","doi":"10.1016/j.sysconle.2024.105885","DOIUrl":"10.1016/j.sysconle.2024.105885","url":null,"abstract":"<div><p>Reproducing kernel Hilbert spaces (RKHSs) are special Hilbert spaces in one-to-one correspondence with positive definite maps called kernels. They are widely employed in machine learning to reconstruct unknown functions from sparse and noisy data. In the last two decades, a subclass known as stable RKHSs has been also introduced in the setting of linear system identification. Stable RKHSs contain only absolutely integrable impulse responses over the positive real line. Hence, they can be adopted as hypothesis spaces to estimate linear, time-invariant and BIBO stable dynamic systems from input–output data. Necessary and sufficient conditions for RKHS stability are available in the literature and it is known that kernel absolute integrability implies stability. Working in discrete-time, in a recent work we have proved that this latter condition is merely sufficient. Working in continuous-time, it is the purpose of this note to prove that the same result holds also for Mercer kernels.</p></div>","PeriodicalId":49450,"journal":{"name":"Systems & Control Letters","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Truncated predictor feedback for a chain of infinite-delayed systems with input saturation","authors":"","doi":"10.1016/j.sysconle.2024.105873","DOIUrl":"10.1016/j.sysconle.2024.105873","url":null,"abstract":"<div><p>A linear system can be regulated by a control signal through a cascade of integrators, as extensively documented in existing literature. However, such controllers often encounter challenges when each link in this chain is affected by time delays, leading to poor performance or even instability. This paper addresses a particularly challenging scenario wherein each connection experiences infinite delays, and the input signal is subject to saturation. To overcome these issues, we propose a truncated predictor feedback controller via the low-gain design. Semi-global stabilization problem of the considered system is solved with the peak magnitude of the input signal provided. One of the novelties of our work lies in the expanded applicability of truncated predictor feedback, which is applied to a system featuring both state and input delays. This stands in contrast to the majority of existing studies that primarily focus on input delays alone. We support our theoretical framework with a simulation example to illustrate its effectiveness.</p></div>","PeriodicalId":49450,"journal":{"name":"Systems & Control Letters","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141936159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cooperatively prescribed performance control for nonlinear multi-agent systems with unknown control directions by event-triggered control","authors":"","doi":"10.1016/j.sysconle.2024.105870","DOIUrl":"10.1016/j.sysconle.2024.105870","url":null,"abstract":"<div><p>In this paper, we investigate the output synchronization problem for a nonlinear multi-agent system class that involves unknown parameters, disturbances, and unknown control coefficients. At the same time, the use of switching threshold event-triggered control not only reduces the computational load and controller update frequency but also balances the system performance. Combined with prescribed performance control, the transient performance of the system is improved as well. Compared with previous studies, the controller proposed in this article ensures that, in the absence of leader, the neighborhood error of each agent evolves within the specified range and eventually tends towards 0 rather than evolves within a residual range. Finally, the effectiveness of the proposed approach is verified through numerical simulations.</p></div>","PeriodicalId":49450,"journal":{"name":"Systems & Control Letters","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sampling controllability of multi-agent systems based on structural decomposition","authors":"","doi":"10.1016/j.sysconle.2024.105882","DOIUrl":"10.1016/j.sysconle.2024.105882","url":null,"abstract":"<div><p>This paper constructs a lower dimensional multi-agent system (MAS) utilizing the structural decomposition of system matrix. Through equivalent transformation, it has been proven that the sampling controllability of the original system is inherited by the lower dimensional system, allowing us to further obtain a criterion for determining the sampling controllability based on topology structure and sampling period. The paper also applies state feedback to the protocol design of MAS during the sampling period, achieving that the sampled-data MAS can still maintain controllability in uncontrollable topologies, and controllability is unaffected by the sampling period. Finally, numerical examples are provided for verification.</p></div>","PeriodicalId":49450,"journal":{"name":"Systems & Control Letters","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141729011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reinforcement learning for inverse linear-quadratic dynamic non-cooperative games","authors":"","doi":"10.1016/j.sysconle.2024.105883","DOIUrl":"10.1016/j.sysconle.2024.105883","url":null,"abstract":"<div><p>The paper addresses the inverse problem in the case of linear-quadratic discrete-time dynamic non-cooperative games. We consider a game with some unknown cost function parameters, referred to as the observed game, that has a set of known feedback laws constituting a Nash equilibrium. The inverse problem is to find values of the cost function parameters that together with the observed game dynamics form a new game, equivalent to the observed one in the sense that it has the same Nash equilibrium. We present a model-based algorithm to solve this problem. We prove the convergence of the algorithm and show that the given set of feedback laws is a Nash equilibrium for the designed game. We also demonstrate how to generate new games with the required properties without repeatedly running the complete algorithm. Moreover, the model-based algorithm is extended to a model-free version that operates without requiring the knowledge of the system matrices, but relies on the ability to collect sufficient data. Simulation results validate the effectiveness of the proposed algorithms.</p></div>","PeriodicalId":49450,"journal":{"name":"Systems & Control Letters","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0167691124001713/pdfft?md5=a1258d39b2325c890d1a133aa921c377&pid=1-s2.0-S0167691124001713-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141639162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Distributed predefined-time constrained social cost minimization problem under the partial information setting","authors":"","doi":"10.1016/j.sysconle.2024.105872","DOIUrl":"10.1016/j.sysconle.2024.105872","url":null,"abstract":"<div><p>In this letter, the social cost minimization problem with coupled equality constraints is studied, where the agents endeavor to collaboratively minimize the sum of all local cost functions, and each local cost function depends on a global decision variable consisting of the decisions of all participants. In a setting where only partial information about one’s own decisions and cost function is available, the first single-time scale predefined-time distributed algorithm based on the time-based-generator scheme is designed to tackle the problem. With the help of the Lyapunov stability theory, it is demonstrated that the algorithm can converge to the optimal solution in an arbitrarily specified time independent of the initial state and control parameters. Finally, the effectiveness of the proposed algorithm is verified by numerical simulations.</p></div>","PeriodicalId":49450,"journal":{"name":"Systems & Control Letters","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141639161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Global adaptive regulation for time-delay nonlinear systems with saturated input","authors":"","doi":"10.1016/j.sysconle.2024.105871","DOIUrl":"10.1016/j.sysconle.2024.105871","url":null,"abstract":"<div><p>In this paper, the global adaptive stabilization problem for a class of uncertain time-delay nonlinear systems with unmeasured state dependent growth and saturated input is addressed by output-feedback. The nonlinearities depend on both the unmeasured states and the unknown polynomial-of-output growth. To handle the unmeasured state and the saturated input, a distinct observer and an auxiliary system with only one high-gain updated in a new form, are introduced, respectively. Moreover, a systematic output-feedback control scheme is proposed by using the method of backstepping. The designed controller can guarantee that all the states of the closed-loop system are global bounded. Finally, a practical example shows the validity of the proposed method.</p></div>","PeriodicalId":49450,"journal":{"name":"Systems & Control Letters","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141622523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}