Automatica最新文献

{"title":"Robust fault estimators for nonlinear systems: An ultra-local model design","authors":"Farhad Ghanipoor ,&nbsp;Carlos Murguia ,&nbsp;Peyman Mohajerin Esfahani ,&nbsp;Nathan van de Wouw","doi":"10.1016/j.automatica.2024.111920","DOIUrl":"10.1016/j.automatica.2024.111920","url":null,"abstract":"<div><div>This paper proposes a nonlinear estimator for the robust reconstruction of process and sensor faults for a class of uncertain nonlinear systems. The proposed fault estimation method augments the system dynamics with an ultra-local (in time) internal state–space representation (a finite chain of integrators) of the fault vector. Next, a nonlinear state observer is designed based on the known parts of the augmented dynamics. This nonlinear filter (observer) reconstructs the fault signal as well as the states of the augmented system. We provide sufficient conditions that guarantee stability of the estimation error dynamics: firstly, asymptotic stability (i.e., exact fault estimation) in the absence of perturbations induced by the fault model mismatch (mismatch between internal ultra-local model for the fault and the actual fault dynamics), uncertainty, external disturbances, and measurement noise and, secondly, Input-to-State Stability (ISS) of the estimation error dynamics is guaranteed in the presence of these perturbations. In addition, to support performance-based estimator design, we provide Linear Matrix Inequality (LMI) conditions for <span><math><msub><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>-gain and <span><math><mrow><msub><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>∞</mi></mrow></msub></mrow></math></span> induced norm and cast the synthesis of the estimator gains as a semi-definite program where the effect of model mismatch and external disturbances on the fault estimation error is minimized in the sense of <span><math><msub><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>-gain, for an acceptable <span><math><mrow><msub><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><msub><mrow><mi>L</mi></mrow><mrow><mi>∞</mi></mrow></msub></mrow></math></span> induced norm with respect to measurement noise. The latter result facilitates a design that explicitly addresses the performance trade-off between noise sensitivity and robustness against model mismatch and external disturbances. Finally, numerical results for a benchmark system illustrate the performance of the proposed methodologies.</div></div>","PeriodicalId":55413,"journal":{"name":"Automatica","volume":"171 ","pages":"Article 111920"},"PeriodicalIF":4.8,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"A non-interior-point continuation method for the optimal control problem with equilibrium constraints","authors":"Kangyu Lin,&nbsp;Toshiyuki Ohtsuka","doi":"10.1016/j.automatica.2024.111940","DOIUrl":"10.1016/j.automatica.2024.111940","url":null,"abstract":"<div><div>This study presents a numerical method for the optimal control problem with equilibrium constraints (OCPEC). It is extremely difficult to solve OCPEC owing to the absence of constraint regularity and strictly feasible interior points. To solve OCPEC efficiently, we first relax the discretized OCPEC to recover the constraint regularity and then map its Karush–Kuhn–Tucker (KKT) conditions into a parameterized system of equations. Subsequently, we solve the parameterized system using a novel two-stage solution method called the non-interior-point continuation method. In the first stage, a non-interior-point method is employed to find an initial solution, which solves the parameterized system using Newton’s method and globalizes convergence using a dedicated merit function. In the second stage, a predictor–corrector continuation method is utilized to track the solution trajectory as a function of the parameter, starting at the initial solution. The proposed method regularizes the KKT matrix and does not enforce iterates to remain in the feasible interior, which mitigates the numerical difficulties in solving OCPEC. Convergence properties are analyzed under certain assumptions. Numerical experiments demonstrate that the proposed method can solve OCPEC while demanding remarkably less computation time than the interior-point method.</div></div>","PeriodicalId":55413,"journal":{"name":"Automatica","volume":"171 ","pages":"Article 111940"},"PeriodicalIF":4.8,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"How do the lengths of switching intervals influence the stability of a dynamical system?","authors":"Vladimir Yu. Protasov ,&nbsp;Rinat Kamalov","doi":"10.1016/j.automatica.2024.111929","DOIUrl":"10.1016/j.automatica.2024.111929","url":null,"abstract":"<div><div>If a linear switching system with frequent switches is stable, will it be stable under arbitrary switches? In general, the answer is negative. Nevertheless, this question can be answered in an explicit form for any concrete system. This is done by finding the mode-dependent critical lengths of switching intervals after which any enlargement does not influence the stability. The solution is given in terms of the exponential polynomials of least deviation from zero on a segment (“Chebyshev-like” polynomials). By proving several theoretical results on exponential polynomial approximation we derive an algorithm for finding such polynomials and for computing the critical switching time. The convergence of the algorithm is estimated and numerical results are provided.</div></div>","PeriodicalId":55413,"journal":{"name":"Automatica","volume":"171 ","pages":"Article 111929"},"PeriodicalIF":4.8,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"A recursive filtering approach to power harmonic detection with stochastic communication delays: Tackling amplify-and-forward relays","authors":"Guhui Li ,&nbsp;Zidong Wang ,&nbsp;Xingzhen Bai ,&nbsp;Zhongyi Zhao ,&nbsp;Yezheng Wang","doi":"10.1016/j.automatica.2024.111968","DOIUrl":"10.1016/j.automatica.2024.111968","url":null,"abstract":"<div><div>This paper focuses on the power harmonic detection problem in smart grids with relay transmissions and stochastic communication delays. A model is established using an orthogonal vector to capture the dynamics of harmonic signals with direct current attenuation components. For the assurance of reliable information delivery, a strategy employing an amplify-and-forward relay with stochastic transmission power is used to schedule data from sensors to the remote filter. Furthermore, a set of random variables that obey Bernoulli distributions is used to characterize the stochastic nature of the communication delays. With the goal of achieving accurate power harmonic detection, a recursive filtering algorithm is aimed to be designed in the presence of the amplify-and-forward relay strategy and stochastic communication delays, which ensures that the desired filter gain parameter is derived recursively by minimizing the upper bound on the filtering error covariance. Ultimately, the effectiveness of the proposed filtering algorithm is demonstrated through simulation experiments on power harmonic detection, thereby verifying its capability in tracking harmonic dynamics.</div></div>","PeriodicalId":55413,"journal":{"name":"Automatica","volume":"171 ","pages":"Article 111968"},"PeriodicalIF":4.8,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Robust finite-time stabilization of linear systems with limited state quantization","authors":"Yu Zhou,&nbsp;Andrey Polyakov,&nbsp;Gang Zheng","doi":"10.1016/j.automatica.2024.111967","DOIUrl":"10.1016/j.automatica.2024.111967","url":null,"abstract":"<div><div>This paper investigates the robust asymptotic stabilization of a linear time-invariant (LTI) system by static feedback with a static state quantization. It is shown that the controllable LTI system can be stabilized to zero in a finite time by means of nonlinear feedback with a quantizer having a limited (finite) number of values (quantization seeds) even when all parameters of the controller and the quantizer are time-invariant. The control design is based on generalized homogeneity. A homogeneous spherical quantizer is introduced. The static homogeneous feedback is shown to be a local (or global) finite-time stabilizer for any controllable linear system (depending on the system matrix). The tuning rules for both the quantizer and the feedback law are obtained in the form of Linear Matrix Inequalities (LMIs). The closed-loop system is proven to be robust with respect to some bounded matched or vanishing mismatched perturbations. Theoretical results are supported by numerical simulations.</div></div>","PeriodicalId":55413,"journal":{"name":"Automatica","volume":"171 ","pages":"Article 111967"},"PeriodicalIF":4.8,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Parallelized robust distributed model predictive control in the presence of coupled state constraints","authors":"Adrian Wiltz,&nbsp;Fei Chen,&nbsp;Dimos V. Dimarogonas","doi":"10.1016/j.automatica.2024.111952","DOIUrl":"10.1016/j.automatica.2024.111952","url":null,"abstract":"<div><div>In this paper, we present a robust distributed model predictive control (DMPC) scheme for dynamically decoupled nonlinear systems which are subject to state constraints, coupled state constraints and input constraints. In the proposed control scheme, all subsystems solve their local optimization problem in parallel and neighbor-to-neighbor communication suffices. The approach relies on consistency constraints which define a neighborhood around each subsystem’s reference trajectory where the state of the subsystem is guaranteed to stay in. Contrary to related approaches, the reference trajectories are improved consecutively. In order to ensure the controller’s robustness against bounded uncertainties, we employ tubes. The presented approach can be considered as a time-efficient alternative to the well-established sequential DMPC. In the end, we briefly comment on an iterative extension. The effectiveness of the proposed DMPC scheme is demonstrated with simulations, and its performance is compared to other DMPC schemes.</div></div>","PeriodicalId":55413,"journal":{"name":"Automatica","volume":"171 ","pages":"Article 111952"},"PeriodicalIF":4.8,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"A generalized projection estimation algorithm","authors":"Patrizio Tomei,&nbsp;Riccardo Marino","doi":"10.1016/j.automatica.2024.111942","DOIUrl":"10.1016/j.automatica.2024.111942","url":null,"abstract":"<div><div>Given a linear regression model in discrete-time containing a vector of <span><math><mi>p</mi></math></span> constant uncertain parameters, this paper addresses the problem of designing an exponentially convergent parameter estimation algorithm, even when the regressor vector is not persistently exciting (not even in a finite time interval). On the basis of the definition of lack of persistency of excitation of order <span><math><mi>q</mi></math></span> for the regressor vector, <span><math><mrow><mn>0</mn><mo>≤</mo><mi>q</mi><mo>≤</mo><mi>p</mi></mrow></math></span> (which coincides with the classical definition of persistency of excitation when <span><math><mrow><mi>q</mi><mo>=</mo><mn>0</mn></mrow></math></span>), a generalized projection estimation algorithm is proposed which guarantees global exponential convergence of the parameter estimation error and allows for the on-line computation of the order <span><math><mi>q</mi></math></span> of the lack of persistency of excitation. When the lack of persistency of excitation is of order zero, global exponential convergence to zero of the parameter estimation error is obtained, recovering a well-known result and the projection estimation algorithm as a special case.</div></div>","PeriodicalId":55413,"journal":{"name":"Automatica","volume":"171 ","pages":"Article 111942"},"PeriodicalIF":4.8,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Reconfigurability evaluation and design for control systems with actuator fault and saturation","authors":"Yuanyuan Tu ,&nbsp;Dayi Wang ,&nbsp;Chengrui Liu ,&nbsp;Xiangyan Zhang","doi":"10.1016/j.automatica.2024.111941","DOIUrl":"10.1016/j.automatica.2024.111941","url":null,"abstract":"<div><div>The issue of reconfiguration-based fault-tolerant control for systems with actuator fault and saturation is addressed. The basic idea behind this work is to evaluate the system reconfigurability to guide the reconfiguration scheme and system structure design. First, a reconfigurability criterion is derived and utilized to quantify the degree of reconfigurability. On this basis, a passive/active combined reconfiguration method is proposed to balance the effectiveness and implementation complexity of the reconfiguration scheme. Moreover, the system structure is optimized to further improve the comprehensive performance of the system. Finally, the effectiveness of the proposed method is illustrated through an application example of the satellite attitude control system.</div></div>","PeriodicalId":55413,"journal":{"name":"Automatica","volume":"171 ","pages":"Article 111941"},"PeriodicalIF":4.8,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Edges’ Riemannian energy analysis for synchronization of multi-agent nonlinear systems over undirected weighted graphs","authors":"Alexandre Cellier-Devaux ,&nbsp;Daniele Astolfi ,&nbsp;Vincent Andrieu","doi":"10.1016/j.automatica.2024.111950","DOIUrl":"10.1016/j.automatica.2024.111950","url":null,"abstract":"<div><div>In this note we investigate the problem of global exponential synchronization of multi-agent systems described by non-linear input affine dynamics. We consider the case of networks described by undirected connected graphs possibly without leader. We present a set of sufficient conditions based on a Riemannian metric approach in order to design a state-feedback distributed control law. Then, we study the convergence properties of the overall network. By exploiting the properties of the edge Laplacian we construct a Lyapunov function that allows to conclude global exponential synchronization of the overall network.</div></div>","PeriodicalId":55413,"journal":{"name":"Automatica","volume":"171 ","pages":"Article 111950"},"PeriodicalIF":4.8,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Remote state estimation with privacy against active eavesdroppers","authors":"Matthew J. Crimson,&nbsp;Justin M. Kennedy,&nbsp;Daniel E. Quevedo","doi":"10.1016/j.automatica.2024.111932","DOIUrl":"10.1016/j.automatica.2024.111932","url":null,"abstract":"<div><div>This paper considers a cyber–physical system under an active eavesdropping attack. A remote legitimate user estimates the state of a linear plant from the state information received from a sensor. Transmissions from the sensor occur via an insecure and unreliable network. An active eavesdropper may perform an attack during system operation. The eavesdropper intercepts transmissions from the sensor, whilst simultaneously sabotaging the data transfer from the sensor to the remote legitimate user to harm its estimation performance. To maintain state confidentiality, we propose an encoding scheme that is activated on the detection of an eavesdropper. Our scheme transmits noise based on a pseudo-random indicator, pre-arranged at the legitimate user and sensor. The transmission of noise harms the eavesdropper’s performance, more than that of the legitimate user. Using the proposed encoding scheme, we impair the eavesdropper’s expected estimation performance, whilst minimizing expected performance degradation at the legitimate user. We explore the trade-off between state confidentiality and legitimate user performance degradation by selecting the probability that the sensor transmits noise. Under certain design choices, the trace of the expected estimation error covariance of the eavesdropper is greater than that of the legitimate user. Numerical examples are provided to illustrate the proposed encoding scheme.</div></div>","PeriodicalId":55413,"journal":{"name":"Automatica","volume":"171 ","pages":"Article 111932"},"PeriodicalIF":4.8,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}