Pub Date : 2026-02-25DOI: 10.1109/LCSYS.2026.3667764
Shida Cao;Bin Zhou;Guangren Duan
For the linear time-invariant systems without a regular relative degree, this note presents a novel criterion based on the matrix echelon form for the existence of transformations making the transformed system have a regular relative degree. Moreover, a method for figuring out all of these transformations is established. Both the row and column relative degree cases are discussed. The proposed criterion is only concerned with the output controllability matrix in the row relative degree case and the input observability matrix in the column relative degree case. From a practical application perspective, the proposed criterion and computation method are easy to implement and incur low computational complexity.
{"title":"Echelon Form Criterion for the Existence of a Regular Relative Degree of Linear Systems","authors":"Shida Cao;Bin Zhou;Guangren Duan","doi":"10.1109/LCSYS.2026.3667764","DOIUrl":"https://doi.org/10.1109/LCSYS.2026.3667764","url":null,"abstract":"For the linear time-invariant systems without a regular relative degree, this note presents a novel criterion based on the matrix echelon form for the existence of transformations making the transformed system have a regular relative degree. Moreover, a method for figuring out all of these transformations is established. Both the row and column relative degree cases are discussed. The proposed criterion is only concerned with the output controllability matrix in the row relative degree case and the input observability matrix in the column relative degree case. From a practical application perspective, the proposed criterion and computation method are easy to implement and incur low computational complexity.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"10 ","pages":"121-126"},"PeriodicalIF":2.0,"publicationDate":"2026-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440677","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 : 2026-02-24DOI: 10.1109/LCSYS.2026.3667820
Ping-Yen Yang;Shun-Pin Hsu
This letter investigates the Laplacian controllability of symmetric directed path and ring graphs, which are prevalent in real-world network applications. The analysis focuses on deriving explicit expressions for the eigenvalues and eigenvectors of the Laplacian matrices associated with these graphs. Based on these expressions, necessary and sufficient conditions for Laplacian controllability are established. The theoretical results are illustrated with practical examples, demonstrating the application of the controllability conditions. The findings of this study contribute to a deeper understanding of network controllability and provide valuable insights for designing and manipulating real-world networks with symmetric directed path and ring topologies.
{"title":"Laplacian Controllability of Symmetric Directed Path and Ring Graphs","authors":"Ping-Yen Yang;Shun-Pin Hsu","doi":"10.1109/LCSYS.2026.3667820","DOIUrl":"https://doi.org/10.1109/LCSYS.2026.3667820","url":null,"abstract":"This letter investigates the Laplacian controllability of symmetric directed path and ring graphs, which are prevalent in real-world network applications. The analysis focuses on deriving explicit expressions for the eigenvalues and eigenvectors of the Laplacian matrices associated with these graphs. Based on these expressions, necessary and sufficient conditions for Laplacian controllability are established. The theoretical results are illustrated with practical examples, demonstrating the application of the controllability conditions. The findings of this study contribute to a deeper understanding of network controllability and provide valuable insights for designing and manipulating real-world networks with symmetric directed path and ring topologies.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"10 ","pages":"103-108"},"PeriodicalIF":2.0,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147362366","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 : 2026-02-20DOI: 10.1109/LCSYS.2026.3666550
Sebastiaan van den Eijnden
Scaled relative graphs provide a promising framework for graphical nonlinear system analysis, extending the classical Nyquist diagram for linear time-invariant systems. Unlike the Nyquist diagram, however, scaled relative graphs do not preserve information linking specific input regimes to corresponding output behaviours, which can lead to conservatism in feedback analysis. In this letter, we present a refined scaled relative graph framework that explicitly accounts for input-specific system behaviours. Drawing inspiration from mixed systems that exhibit different input-output properties under different input regimes, the proposed framework defines scaled relative graphs for subsets of inputs and outputs sharing specific features. We establish a feedback stability result based on the topological separation of input- and output-specific scaled relative graphs, and provide a systematic method for their construction using integral quadratic constraints.
{"title":"Decomposition of Scaled Relative Graphs: A Mixed Systems Approach","authors":"Sebastiaan van den Eijnden","doi":"10.1109/LCSYS.2026.3666550","DOIUrl":"https://doi.org/10.1109/LCSYS.2026.3666550","url":null,"abstract":"Scaled relative graphs provide a promising framework for graphical nonlinear system analysis, extending the classical Nyquist diagram for linear time-invariant systems. Unlike the Nyquist diagram, however, scaled relative graphs do not preserve information linking specific input regimes to corresponding output behaviours, which can lead to conservatism in feedback analysis. In this letter, we present a refined scaled relative graph framework that explicitly accounts for input-specific system behaviours. Drawing inspiration from mixed systems that exhibit different input-output properties under different input regimes, the proposed framework defines scaled relative graphs for subsets of inputs and outputs sharing specific features. We establish a feedback stability result based on the topological separation of input- and output-specific scaled relative graphs, and provide a systematic method for their construction using integral quadratic constraints.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"10 ","pages":"115-120"},"PeriodicalIF":2.0,"publicationDate":"2026-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440676","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 : 2026-02-18DOI: 10.1109/LCSYS.2026.3666076
Athanasios K. Gkesoulis;Haris E. Psillakis;George C. Karras;Charalampos P. Bechlioulis
This letter addresses prescribed performance control (PPC) for uncertain multi-input multi-output (MIMO) nonlinear systems subject to saturated and coupled inputs. The proposed controller requires no model parameter knowledge and is of low implementation complexity, i.e., no regressors, observers, or approximation structures are utilized. We derive explicit feasibility conditions linking saturation levels to performance envelopes, system parameters, gains as well as disturbances, and effectively extend the low-complexity results on prescribed performance control with input saturation to the case of input coupling. Boundedness of all closed-loop signals and prescribed-performance tracking are established. A planar two-link manipulator simulation validates the approach.
{"title":"Prescribed Performance Control of Uncertain MIMO Nonlinear Systems With Coupled and Constrained Inputs","authors":"Athanasios K. Gkesoulis;Haris E. Psillakis;George C. Karras;Charalampos P. Bechlioulis","doi":"10.1109/LCSYS.2026.3666076","DOIUrl":"https://doi.org/10.1109/LCSYS.2026.3666076","url":null,"abstract":"This letter addresses prescribed performance control (PPC) for uncertain multi-input multi-output (MIMO) nonlinear systems subject to saturated and coupled inputs. The proposed controller requires no model parameter knowledge and is of low implementation complexity, i.e., no regressors, observers, or approximation structures are utilized. We derive explicit feasibility conditions linking saturation levels to performance envelopes, system parameters, gains as well as disturbances, and effectively extend the low-complexity results on prescribed performance control with input saturation to the case of input coupling. Boundedness of all closed-loop signals and prescribed-performance tracking are established. A planar two-link manipulator simulation validates the approach.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"10 ","pages":"97-102"},"PeriodicalIF":2.0,"publicationDate":"2026-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147299647","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 : 2026-02-17DOI: 10.1109/LCSYS.2026.3665795
Yangrui Zhang;Tianjian Jiang;Zhongxuan Cai;Yiding Ji
Timed reach-avoid specifications, a subset of Signal Temporal Logic (STL), provide an expressive framework for specifying complex tasks in dynamic systems. This letter introduces a novel framework that encodes these specifications into a quadratic programming (QP) controller using backup control barrier functions (backup CBFs). Unlike existing approaches that rely on predefined safe sets, we utilize a backup control strategy within a prediction horizon to construct time-varying implicit sets online. Specifically, we address the limitation of standard backup CBFs regarding finite-time convergence by introducing contractive implicit sets. Rigorous analysis of the time-varying properties confirms that backup CBFs enforce system forward invariance within these contractive sets, driving real-time trajectories to satisfy given specifications. Our method unifies high-level planning with continuous control, while does not require explicit safe set computation for Eventually formulas or predefined performance functions. Numerical simulations validate the performance of our approach in safe planning and control of mobile robots.
{"title":"Safety-Critical Control Under Timed Reach–Avoid Specifications: A Backup Control Barrier Function Approach","authors":"Yangrui Zhang;Tianjian Jiang;Zhongxuan Cai;Yiding Ji","doi":"10.1109/LCSYS.2026.3665795","DOIUrl":"https://doi.org/10.1109/LCSYS.2026.3665795","url":null,"abstract":"Timed reach-avoid specifications, a subset of Signal Temporal Logic (STL), provide an expressive framework for specifying complex tasks in dynamic systems. This letter introduces a novel framework that encodes these specifications into a quadratic programming (QP) controller using backup control barrier functions (backup CBFs). Unlike existing approaches that rely on predefined safe sets, we utilize a backup control strategy within a prediction horizon to construct time-varying implicit sets online. Specifically, we address the limitation of standard backup CBFs regarding finite-time convergence by introducing contractive implicit sets. Rigorous analysis of the time-varying properties confirms that backup CBFs enforce system forward invariance within these contractive sets, driving real-time trajectories to satisfy given specifications. Our method unifies high-level planning with continuous control, while does not require explicit safe set computation for Eventually formulas or predefined performance functions. Numerical simulations validate the performance of our approach in safe planning and control of mobile robots.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"10 ","pages":"109-114"},"PeriodicalIF":2.0,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147362576","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 : 2026-02-16DOI: 10.1109/LCSYS.2026.3665232
Xiao He;Shanling Dong;Enjun Liu;Zheng-Guang Wu;Meiqin Liu;Hongdong Wang
The letter studies the problem of fault-tolerant event-triggered depth tracking control for autonomous underwater vehicles subject to disturbance and faults. Initially, a fault-tolerant prescribed-time observer is designed to estimate the system state, where the estimation errors converge to zero at a specified convergence time regardless of initial conditions. Then, a fault-tolerant event-triggered depth tracking control law is designed based on the observer’s state, where the dynamic periodic event-triggered strategy is employed to reduce the communication burden. It is proved that the proposed control method can address the depth tracking control problem via the Lyapunov function technique. The proposed method is validated through the simulation example.
{"title":"Fault-Tolerant Dynamic Periodic Event-Based Depth Control of AUVs With Prescribed-Time Observer","authors":"Xiao He;Shanling Dong;Enjun Liu;Zheng-Guang Wu;Meiqin Liu;Hongdong Wang","doi":"10.1109/LCSYS.2026.3665232","DOIUrl":"https://doi.org/10.1109/LCSYS.2026.3665232","url":null,"abstract":"The letter studies the problem of fault-tolerant event-triggered depth tracking control for autonomous underwater vehicles subject to disturbance and faults. Initially, a fault-tolerant prescribed-time observer is designed to estimate the system state, where the estimation errors converge to zero at a specified convergence time regardless of initial conditions. Then, a fault-tolerant event-triggered depth tracking control law is designed based on the observer’s state, where the dynamic periodic event-triggered strategy is employed to reduce the communication burden. It is proved that the proposed control method can address the depth tracking control problem via the Lyapunov function technique. The proposed method is validated through the simulation example.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"10 ","pages":"91-96"},"PeriodicalIF":2.0,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147299556","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 : 2026-02-12DOI: 10.1109/LCSYS.2026.3664253
Zhiran Ma;Jiahong Guo
This letter investigates fast first-order methods for nonconvex optimization, inspired by a second-order dynamical system with vanishing damping and strongly convex dry friction. By discretizing this system, we propose a strongly convex dry-friction inertial proximal gradient algorithm, and establish its convergence and geometric convergence rate, under mild conditions. Moreover, an accelerated variant, which combines Nesterov’s accelerated gradient method with the strongly convex dry-friction inertial proximal gradient method, is introduced. Numerical experiments are reported to demonstrate the effectiveness of the proposed algorithms.
{"title":"Fast Convergent Inertial Proximal Gradient Algorithms With Dry Friction for Nonconvex Optimization","authors":"Zhiran Ma;Jiahong Guo","doi":"10.1109/LCSYS.2026.3664253","DOIUrl":"https://doi.org/10.1109/LCSYS.2026.3664253","url":null,"abstract":"This letter investigates fast first-order methods for nonconvex optimization, inspired by a second-order dynamical system with vanishing damping and strongly convex dry friction. By discretizing this system, we propose a strongly convex dry-friction inertial proximal gradient algorithm, and establish its convergence and geometric convergence rate, under mild conditions. Moreover, an accelerated variant, which combines Nesterov’s accelerated gradient method with the strongly convex dry-friction inertial proximal gradient method, is introduced. Numerical experiments are reported to demonstrate the effectiveness of the proposed algorithms.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"10 ","pages":"85-90"},"PeriodicalIF":2.0,"publicationDate":"2026-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147299685","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 : 2026-02-02DOI: 10.1109/LCSYS.2026.3660095
Tianyi Zhong;David Angeli
In this letter, we study the problem of coordinating the charging pattern of strategic electric vehicle (EV) users by taking carbon intensity into consideration. We implement an incentive mechanism to address the misalignment between individual cost minimisation and system-wide carbon reduction. This mechanism leverages a modified VCG framework tailored to distributed computation, enabling the system to elicit flexible participation from EV users without compromising environmental goals. While the framework supports various optimisation algorithms, we specifically select a cutting plane-based distributed algorithm due to its computational efficiency.
{"title":"Incentive Mechanism Design for Carbon-Aware Electric Vehicle Charging Coordination Problem","authors":"Tianyi Zhong;David Angeli","doi":"10.1109/LCSYS.2026.3660095","DOIUrl":"https://doi.org/10.1109/LCSYS.2026.3660095","url":null,"abstract":"In this letter, we study the problem of coordinating the charging pattern of strategic electric vehicle (EV) users by taking carbon intensity into consideration. We implement an incentive mechanism to address the misalignment between individual cost minimisation and system-wide carbon reduction. This mechanism leverages a modified VCG framework tailored to distributed computation, enabling the system to elicit flexible participation from EV users without compromising environmental goals. While the framework supports various optimisation algorithms, we specifically select a cutting plane-based distributed algorithm due to its computational efficiency.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"10 ","pages":"79-84"},"PeriodicalIF":2.0,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146175799","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 : 2026-01-30DOI: 10.1109/LCSYS.2026.3659802
Jin Zhou;Haoran Liu;Shuaibing Zhu;Jun-An Lu;Jinhu Lü
This letter presents a theoretical framework for estimating the trajectory-based region of attraction in nonlinear higher-order networks. A Lyapunov-based criterion is established for time-varying systems to determine the domain in which all trajectories converge to a reference trajectory. The result is expressed as a spherical region characterized by parameters of the linearized dynamics. Two corollaries admit closed-form and eigenmode-based estimations, respectively enabling a direct region radius calculation and reducing system dimension significantly. Numerical simulations on a higher-order network of forced pendulums validate the proposed analysis and demonstrate its accuracy and efficiency.
{"title":"Trajectory-Based Region of Attraction Estimation on Higher-Order Networked Nonlinear Systems","authors":"Jin Zhou;Haoran Liu;Shuaibing Zhu;Jun-An Lu;Jinhu Lü","doi":"10.1109/LCSYS.2026.3659802","DOIUrl":"https://doi.org/10.1109/LCSYS.2026.3659802","url":null,"abstract":"This letter presents a theoretical framework for estimating the trajectory-based region of attraction in nonlinear higher-order networks. A Lyapunov-based criterion is established for time-varying systems to determine the domain in which all trajectories converge to a reference trajectory. The result is expressed as a spherical region characterized by parameters of the linearized dynamics. Two corollaries admit closed-form and eigenmode-based estimations, respectively enabling a direct region radius calculation and reducing system dimension significantly. Numerical simulations on a higher-order network of forced pendulums validate the proposed analysis and demonstrate its accuracy and efficiency.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"10 ","pages":"73-78"},"PeriodicalIF":2.0,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146175794","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 : 2026-01-29DOI: 10.1109/LCSYS.2026.3659158
Jorge Dávila;Francisco Javier Bejarano
This letter presents a design methodology for a robust distributed observer for a class of linear time-invariant systems affected by unknown inputs. The proposed methodology is implemented within a distributed sensor network, allowing for accurate local estimation of the full state after a finite-time transient, even when the system is affected by unknown inputs. The observer utilizes a compensation term based on high-order sliding modes, ensuring that each sensor accurately estimates the locally observable states after a finite-time transient phase. Furthermore, via a consensus-based algorithm, each sensor uses the distributed information to estimate the complete state of the system in finite time.
{"title":"Finite-Time Distributed State Estimation for Linear Systems With Unknown Inputs via Sliding Modes","authors":"Jorge Dávila;Francisco Javier Bejarano","doi":"10.1109/LCSYS.2026.3659158","DOIUrl":"https://doi.org/10.1109/LCSYS.2026.3659158","url":null,"abstract":"This letter presents a design methodology for a robust distributed observer for a class of linear time-invariant systems affected by unknown inputs. The proposed methodology is implemented within a distributed sensor network, allowing for accurate local estimation of the full state after a finite-time transient, even when the system is affected by unknown inputs. The observer utilizes a compensation term based on high-order sliding modes, ensuring that each sensor accurately estimates the locally observable states after a finite-time transient phase. Furthermore, via a consensus-based algorithm, each sensor uses the distributed information to estimate the complete state of the system in finite time.","PeriodicalId":37235,"journal":{"name":"IEEE Control Systems Letters","volume":"10 ","pages":"61-66"},"PeriodicalIF":2.0,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146175791","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：