{"title":"Adaptive Control for Nonlinear Systems With Input and Output Quantization Under DoS Attacks","authors":"Xin Xie, Fang Wang","doi":"10.1002/acs.70004","DOIUrl":"https://doi.org/10.1002/acs.70004","url":null,"abstract":"<div>\u0000 \u0000 <p>Under intermittent cyber attacks, an adaptive control strategy has been proposed for a class of nonlinear systems with input and output quantization. Unlike existing studies on denial-of-service attacks (DoS), the system dynamics in this paper are unknown. Since the system dynamics are unknown and both input and output signals are affected by DoS attacks, system variables are not directly observable. To address this issue, a fuzzy observer with switchable gains is proposed. In contrast to conventional DoS attacks research, both input and output signals in this work are quantized prior to transmission, rendering traditional backstepping control methods inapplicable. To solve this problem, the following steps are proposed: Firstly, an auxiliary intermediate controller is designed using the unquantized states. Secondly, by replacing the unquantized states with quantized states in the auxiliary intermediate controller, the intermediate controller and the actual controller are obtained. Thirdly, to compensate for the impact of quantization errors, Lemma 4 is introduced, and the control strategies are first proposed to guarantee the stability of the nonlinear system in the presence of DoS attacks. Furthermore, simulation results are presented to demonstrate the efficiency of the proposed control method.</p>\u0000 </div>","PeriodicalId":50347,"journal":{"name":"International Journal of Adaptive Control and Signal Processing","volume":"40 3","pages":"470-485"},"PeriodicalIF":3.8,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147568496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 Neural Network-Based Adaptive Event-Triggered Control for Virtual Coupling High-Speed Trains With Unknown Parameters","authors":"Hui Zhao, Hanhong Cui, Xuewu Dai, Yuan Zhao","doi":"10.1002/acs.70010","DOIUrl":"https://doi.org/10.1002/acs.70010","url":null,"abstract":"<div>\u0000 \u0000 <p>To cope with the effects of unknown resistance parameters, additional resistance, and high-frequency controller updating in the cooperation control of virtual-coupling high-speed train systems, this paper proposes a neural network-based adaptive event-triggered control scheme for trains. Firstly, with the train-to-train communication mode, a synthetic tracking error and its converted form are proposed to restrain the speed and position errors of trains based on the train model. Then, for the unknown resistance parameters and bounded additional resistance, a radial basis function neural network (RBFNN) based adaptive control scheme is investigated to realize the cooperative operation of trains. By incorporating the event-triggered mechanism, the communication source between the controller and actuator can be saved by reducing unnecessary controller updating. In addition, the stability condition of virtual coupling train systems is presented by the convergence analysis of the synthetic tracking error. Finally, simulation experiments are conducted to verify that the control scheme is able to realize cooperation of virtual coupling train systems in the presence of unknown parameters.</p>\u0000 </div>","PeriodicalId":50347,"journal":{"name":"International Journal of Adaptive Control and Signal Processing","volume":"40 3","pages":"522-533"},"PeriodicalIF":3.8,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147568506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Hopfield Neural Networks for Online Constrained Parameter Estimation With Time-Varying Dynamics and Disturbances","authors":"Miguel Pedro Silva","doi":"10.1002/acs.70011","DOIUrl":"https://doi.org/10.1002/acs.70011","url":null,"abstract":"<p>This paper proposes two projector-based Hopfield neural network (HNN) estimators for online, constrained parameter estimation under time-varying data, additive disturbances, and slowly drifting physical parameters. The first is a constraint-aware HNN that enforces linear equalities and inequalities (via slack neurons) and continuously tracks the constrained least-squares target. The second augments the state with compensation neurons and a concatenated regressor to absorb bias-like disturbance components within the same energy function. For both estimators, we establish global uniform ultimate boundedness with explicit convergence rate and ultimate bound, and we derive practical tuning rules that link the three design gains to closed-loop bandwidth and steady-state accuracy. We also introduce an online identifiability monitor that adapts the constraint weight and time step, and, when needed, projects updates onto identifiable subspaces to prevent drift in poorly excited directions. A two-degree-of-freedom mass-spring-damper study with Monte Carlo trials compares the proposed HNN estimators against projector-based recursive least squares, disturbance-aware projector-based Kalman filtering, and disturbance-aware projector-based moving-horizon estimation. The HNN estimators achieve competitive or superior accuracy with zero constraint violations, reduced disturbance-induced bias (especially with compensation), and low per-step computational cost suitable for high-rate deployment.</p>","PeriodicalId":50347,"journal":{"name":"International Journal of Adaptive Control and Signal Processing","volume":"40 3","pages":"544-564"},"PeriodicalIF":3.8,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/acs.70011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147570315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Khalid Saidi, El Houssaine Tissir, Noreddine Chaibi
{"title":"Robust Fault \u0000 \u0000 \u0000 \u0000 \u0000 H\u0000 \u0000 \u0000 ∞\u0000 \u0000 \u0000 \u0000 $$ {H}_{infty } $$\u0000 Filtering Design in Finite Frequency Domain for Discrete-Time Switched Singular Systems","authors":"Khalid Saidi, El Houssaine Tissir, Noreddine Chaibi","doi":"10.1002/acs.70015","DOIUrl":"https://doi.org/10.1002/acs.70015","url":null,"abstract":"<div>\u0000 \u0000 <p>The present paper focuses on the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mrow>\u0000 <mi>H</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mi>∞</mi>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {H}_{infty } $$</annotation>\u0000 </semantics></math> filtering problem for a class of discrete-time switched singular (SS) systems with faults and finite frequency (FF) input signals under an arbitrary switching signal. The frequencies of the unknown input disturbance are assumed to be in a finite range. The objective is to design a linear mode-dependent filter guaranteeing the asymptotic stability of the filtering error system with a prescribed <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mrow>\u0000 <mi>H</mi>\u0000 </mrow>\u0000 <mrow>\u0000 <mi>∞</mi>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 <annotation>$$ {H}_{infty } $$</annotation>\u0000 </semantics></math> performance bound in an FF range. Based on the generalized Kalman-Yakubovic-Popov lemma, multiple Lyapunov–Krasovskii functional, and some free weighting matrices are used to provide an additional degree of freedom. Efficient conditions are formulated in terms of linear matrix inequalities. The proposed method is designed in the FF domain to reduce the conservativeness generated by those designed in the entire frequency (EF) domain. Finally, numerical examples are provided to illustrate the advantages and the effectiveness of the proposed approach.</p>\u0000 </div>","PeriodicalId":50347,"journal":{"name":"International Journal of Adaptive Control and Signal Processing","volume":"40 3","pages":"653-673"},"PeriodicalIF":3.8,"publicationDate":"2026-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147562673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}