Article
Automation & Control Systems
Farnoosh Rahmanian, Mohammad Hassan Asemani
Summary: The purpose of this article is to address the design of stabilizing controller for linear parameter varying positive systems with multiple time-invariant delays. The proposed control strategy includes a parameter varying state-feedback controller. A Lyapunov approach is utilized to provide a complete solution to the design problem. The effectiveness of the obtained outcomes is guaranteed by presenting a practical example of a deep brain stimulation system used in Parkinson's treatment.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2022)
Article
Mathematics, Applied
Junkang Tian, Zerong Ren, Yanmin Liu
Summary: This paper studies the stability analysis of systems with an interval time-varying delay. New integral inequalities are introduced and less conservative stability criteria are proposed based on these inequalities. The advantages of these criteria are demonstrated through numerical examples.
Article
Computer Science, Information Systems
Antonio Gonzalez
Summary: This paper investigates the control design of interconnected time delay systems using distributed predictor-feedback delay compensation approaches and event-triggered mechanism. By introducing new weighting factors for each local prediction term, the proposed distributed predictor-feedback control provides extra degree of freedom for control synthesis and addresses the design of weighting factors and event-triggered parameters through an algorithm based on LMI and CCL. Simulation results demonstrate the improvements achieved and validate the effectiveness of the proposed method.
INFORMATION SCIENCES
(2021)
Article
Mathematics
Shenping Xiao, Jin Yu, Simon X. Yang, Yongfeng Qiu
Summary: This article studies the stability problem of linear systems with time-varying delays. A new negative condition is established for a class of quadratic functions within a closed set. Based on this condition, stability criteria for the system are derived by constructing an appropriate Lyapunov-Krasovskii functional. Two numerical examples demonstrate that these criteria are efficient and outperform existing methods.
Article
Mathematics, Applied
Hadi Gholami, Mohammad Hossein Shafiei
Summary: This paper designs static and dynamic output feedback controllers for a class of switched nonlinear time-delay systems to achieve finite-time boundedness under the presence of disturbances and uncertainties. An H-infinity index with respect to disturbances is guaranteed using auxiliary matrices and the average dwell time method. The theorems presented in this paper are less conservative and provide more degrees of freedom for feasible solutions compared to existing literature.
APPLIED MATHEMATICS AND COMPUTATION
(2021)
Article
Engineering, Multidisciplinary
Shuning Niu, Wu-Hua Chen, Xiaomei Lu
Summary: This paper addresses the problem of sliding mode control for linear uncertain impulsive systems with time delays and matched disturbances. A novel SMC scheme based on an integral-type sliding function and impulse regulation is proposed, and a linear delayed state feedback control law is introduced to stabilize the resulting sliding mode dynamics. The desired switching gains are obtained through convex optimization, and the theoretical results are validated in a practical application with various impulse inputs.
APPLIED MATHEMATICAL MODELLING
(2023)
Article
Automation & Control Systems
Hicham El Aiss, Redouane Chaibi, Ahmed El Hajjaji, Abdelaziz Hmamed
Summary: This paper investigates the input-output stability analysis and stabilisation of discrete Takagi-Sugeno fuzzy systems with a time-varying delay using an input-output approach and a scaled small gain theorem. Two separate stability criteria are formulated and the input-output stabilisation problem is resolved through the parallel distributed compensation scheme. The conditions obtained are presented in terms of linear matrix inequalities, and three numerical examples are provided to demonstrate the advantages of the proposed method.
INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE
(2021)
Article
Automation & Control Systems
Zhenhua Wang, Yilian Zhang, Mouquan Shen, Yi Shen
Summary: This article studies set-membership estimation for discrete-time linear time-varying systems with unknown-but-bounded uncertainties. An ellipsoidal set-membership filtering method with a new estimator is proposed, and it is shown that the optimal estimation results obtained by two existing methods are equivalent to the special cases of the proposed method.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Graziano Chesi
Summary: This article addresses the problems of establishing structural stability and the L-2 gain of 2-D mixed continuous-discrete time systems. The first contribution is to show that Lyapunov functions quadratically dependent on the frequency are exact for establishing structural stability. The second contribution is to propose a novel linear matrix inequality (LMI) necessary and sufficient condition for establishing the existence of such Lyapunov functions. The third contribution is to show that the proposed methodology can be used to establish upper bounds on the L-2 gain, in particular, deriving a novel necessary and sufficient LMI condition based on Lyapunov functions quadratically dependent on the frequency. Finally, the article presents the generalization of the proposed methodology to nonmixed 2-D systems.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2022)
Article
Computer Science, Artificial Intelligence
Yunfei Qiu, Ju H. H. Park, Changchun Hua, Xijuan Wang
Summary: This article investigates the stability of Takagi-Sugeno (T-S) fuzzy systems with time-varying delay. Firstly, a novel Lyapunov-Krasovskii functional (LKF) is proposed by fully utilizing single integral polynomial-delay-product terms and membership-function-dependent matrices, considering more delay information. Secondly, by introducing negative integral estimation inequalities and polynomial inequality, the estimation gap of derivatives is further decreased. As a result, a less conservative criterion is presented. Finally, examples are used to verify the validity of the stability approach.
IEEE TRANSACTIONS ON FUZZY SYSTEMS
(2023)
Article
Mathematics, Applied
JunMin Park, Nam Kyu Kwon, Seok Young Lee
Summary: This paper addresses the stability analysis of linear discrete-time systems with time-varying delays. To reduce conservatism in stability criteria, the paper proposes extended affine Bessel summation inequalities that provide affine upper bounds of an extended summation quadratic function. It also provides notes on the correlation among several summation inequalities, demonstrating that an increase in the degree of the developed affine Bessel summation inequalities only reduces conservatism. Two numerical examples effectively demonstrate the reduction of conservatism due to the proposed summation inequalities in terms of stability regions expressed as delay bounds.
APPLIED MATHEMATICS AND COMPUTATION
(2023)
Article
Automation & Control Systems
Ayyoub Ait Ladel, Abdellah Benzaouia, Rachid Outbib, Mustapha Ouladsine
Summary: This paper addresses the issues of state/fault estimation and observer-based control for switched systems with sensor faults. A new separation principle is developed using the mode-dependent average dwell time concept and Lyapunov stability theory, allowing formalizing the observer-based controller design in the form of linear matrix inequalities. The practicality and efficiency of the obtained results are demonstrated through examples including a HiMAT aircraft technology example, a DC-DC boost converter example, and a numerical example.
Article
Automation & Control Systems
El Hafid Chelliq, Mohammed Alfidi, Zakaria Chalh
Summary: In this paper, the admissibility and robust H infinity controller design are investigated for uncertain 2-D continuous singular systems with interval time-varying delays and norm-bounded parameter uncertainties. A new delay-dependent admissibility condition is obtained by utilizing an augmented Lyapunov-Krasovskii's functional and combining the Wirtinger inequality with an improved reciprocally convex approach. Then, a robust controller is designed based on a linear matrix inequality. Numerical examples are presented to demonstrate the effectiveness of the proposed methods.
INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE
(2023)
Article
Mathematics, Applied
Zerong Ren, Junkang Tian
Summary: This paper researches the problem of stability analysis for distributed time-delay systems. A newly augmented Lyapunov-Krasovskii functional (LKF) is introduced via a generalized delay partitioning approach, and a less conservative stability criterion is derived by introducing a novel Jensen inequality. The stability condition is given in terms of linear matrix inequality.
Article
Automation & Control Systems
Sahand Hadizadeh Kafash, Jusin Ruths
Summary: In this article, a convex optimization framework is proposed for verifying the reachability of a desired set in discrete-time linear time-invariant systems. The method shows high adaptability, as demonstrated by numerical examples.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2022)
Article
Automation & Control Systems
Chenchen Fan, James Lam, Xiaochen Xie, Panshuo Li
Summary: This article addresses the stability and stabilization of almost periodic piecewise linear systems (APPLSs) with uncertain dwell time of subsystems. A novel mixed-mode time-varying Lyapunov function is constructed, considering the uncertainty in dwell time for the first time. A sufficient condition is proposed to guarantee the exponential stability of the system, where the switching instants over each period are unknown and inaccessible except their bounds. Additionally, a periodic time-scheduled state-feedback control approach is developed to stabilize the APPLS affected by dwell time uncertainty and possibly unstabilizable subsystem dynamics. The effectiveness of the proposed approach is demonstrated through a numerical example involving comparative case studies.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Bohao Zhu, James Lam, Xiaoqi Song, Hong Lin, Jason Ying Kuen Chan, Ka-Wai Kwok
Summary: This paper focuses on the stability analysis and stabilization of periodic piecewise positive systems. A time-scheduled copositive Lyapunov function is constructed to establish an equivalent stability condition for periodic piecewise positive systems. The spectral radius characterization of the state transition matrix is proposed based on the asymptotic stability condition, and the relation between the spectral radius and the convergent rate of the system is revealed. An iterative algorithm is developed to stabilize the system by reducing the spectral radius of the state transition matrix. Numerical examples are provided to illustrate the results.
ASIAN JOURNAL OF CONTROL
(2023)
Article
Automation & Control Systems
Ali Kazemy, Jinrong Liu, James Lam
Summary: This paper addresses the design problem of multiloop networked control systems under interchange attack, a new type of attack that can be more destructive than other types of attacks. The paper first considers multiple sampled-data control loops that use a shared communication network for data transmission, and formulates the overall closed-loop systems with the proposed attack in a unified stochastic delay system. Conditions for H infinity control design problem are derived using Lyapunov-Krasovskii theory and stochastic analysis techniques. Simulation results with inverted pendula demonstrate the effectiveness of the proposed method and compare the effects of DoS attack and interchange attack.
ASIAN JOURNAL OF CONTROL
(2023)
Article
Engineering, Multidisciplinary
Xiaoling Wang, Zhen Fan, Lin Wang, Housheng Su, James Lam
Summary: In this paper, a sensor network is utilized to tackle the distributed observer design problem for a linear time-invariant mobile target system with constant or time-varying velocity. Each sensor only has access to a partial portion of the target's output information. The sensors are equipped with consensus-based algorithms for state estimation using local measurements and leader-following flocking-like algorithms for collision avoidance, communication maintenance, and target tracking. The proposed adaptive coupling gains enable the construction of a fully distributed observer that is independent of the communication topology associated with the sensor network. Numerical simulations demonstrate the effectiveness of the proposed theoretical results.
IEEE TRANSACTIONS ON NETWORK SCIENCE AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Jiaren Xiao, Quanyu Dai, Xiaochen Xie, Qi Dou, Ka-Wai Kwok, James Lam
Summary: In this study, we propose a domain adaptive graph infomax method that computes node representations through neighborhood aggregation and maximizes mutual information between node representations and global summaries to encode global structural information. Conditional adversarial networks are used to reduce the domain discrepancy by aligning the multimodal distributions of node representations. Experimental results on real-world datasets validate the performance of our method in comparison with state-of-the-art baselines.
IEEE TRANSACTIONS ON NETWORK SCIENCE AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Liqing Wang, Zheng-Guang Wu, James Lam
Summary: This paper studies the output feedback control (OFC) stabilization of hidden Markov Boolean control networks (HMBCNs). The OFC problems are formulated in algebraic form using the semi-tensor product of matrices. All feasible OFC gains are characterized. A specific type of attack, called shifting attack, is investigated for HMBCNs. Necessary and sufficient conditions for the security of HMBCNs under shifting attacks are presented, along with constraints for attacked systems. Furthermore, necessary and sufficient conditions for the security of HMBCNs with ?-measurements protected are presented, and the minimum number of measurements to be protected is elaborated. Finally, a simulation example based on a biological system is provided to demonstrate the effectiveness of the obtained results.
IEEE TRANSACTIONS ON NETWORK SCIENCE AND ENGINEERING
(2023)
Article
Computer Science, Artificial Intelligence
Jiaren Xiao, Quanyu Dai, Xiaochen Xie, James Lam, Ka-Wai Kwok
Summary: The high cost of data labeling results in node label shortage. To address this, a graph-based semi-supervised learning method is proposed, which leverages unlabeled nodes to train together with scarce labeled nodes. An attention-based aggregator is designed to generate node representations by aggregating information from neighboring nodes, and adversarial training is employed to improve robustness and generalization.
KNOWLEDGE-BASED SYSTEMS
(2023)
Article
Robotics
Liangliang Wang, James Lam, Xiaojiao Chen, Jing Li, Runzhi Zhang, Yinyin Su, Zheng Wang
Summary: Compared with rigid robots, soft robots have inherent compliance and advantages in flexible and safe tasks. However, sensing the high dimensional body deformation of soft robots is a challenge. This work proposes a bioinspired architecture to endow soft robots with body movement awareness, using paralleled soft pneumatic chambers as receptors for sensing body deformation. The use of redundant receptors and deep learning tools for generating the kinematic model is explored. Additionally, solutions are presented for achieving graceful degradation in response to receptor failures, enabling soft robots with proprioception capability for closed-loop control and interaction with the environment.
Article
Mathematics, Applied
Zhiguang Feng, Xinyue Zhang, James Lam, Chenchen Fan
Summary: This paper addresses the estimation problem of the reachable set for switched singular systems with state jump under initial condition and bounded peak disturbance. Sufficient conditions are derived using lemmas and linear matrix inequalities, which ensure that the state trajectory of the system remains within a closed bounded set. The obtained results are validated through numerical examples.
APPLIED MATHEMATICS AND COMPUTATION
(2023)
Article
Mathematics, Applied
Jason J. R. Liu, James Lam, Xiaomei Wang, Ka-Wai Kwok
Summary: This paper addresses the challenging problem of designing proportional-derivative (PD) controllers for positive linear systems in the discrete-time domain. The specific focus is on designing a PD controller for a system with constant time delay that ensures both closed-loop stability and positivity preservation. The synthesis process considers the additive gain variation of the controller. The paper presents systematic formulation and tractable algorithms for finding the PD controller gains for positive stabilization, and validates the performance through numerical examples. (c) 2023 Elsevier Inc. All rights reserved.
APPLIED MATHEMATICS AND COMPUTATION
(2023)
Article
Engineering, Electrical & Electronic
Chang Zhao, Hong Lin, Yuman Li, Shi Liang, James Lam
Summary: This article addresses the remote state estimation problems of cyber-physical systems (CPSs) under deception attacks. A scheduler and a detector are jointly designed to solve the computational issue, resulting in a computationally efficient remote estimator. The stability condition for the estimator is established, and the scheduling threshold for guaranteeing stability is discussed.
IEEE SENSORS JOURNAL
(2023)
Article
Automation & Control Systems
Bohao Zhu, James Lam, Xiujuan Lu, Ka-Wai Kwok
Summary: This letter investigates stability issues related to linear discrete-time cone-preserving systems with time-varying delays. The study examines the monotonicity of discrete-time systems with cone invariance and provides equivalent asymptotic stability conditions for discrete-time cone-preserving systems with time-varying delays based on the monotonicity of cone-preserving systems and the comparison principle. The results indicate that time delays do not affect asymptotic stability and also analyze the alpha-exponential stability to characterize the decay rate of the system. A numerical example is presented to illustrate the theoretical findings. These results contribute to the understanding of stability analysis of cone-preserving systems with time-varying delays.
IEEE CONTROL SYSTEMS LETTERS
(2023)
Article
Automation & Control Systems
Chengyan Zhao, Bohao Zhu, Masaki Ogura, James Lam
Summary: This letter addresses the optimization problems of discrete-time positive linear systems. It introduces parameterized system coefficient matrices and optimizes system parameters to solve the synthesis problem. By utilizing results from positive linear systems and nonnegative matrix theory, the authors show that the optimization problems of minimizing parameter tuning cost while satisfying certain norm constraints can be reduced to geometric programming problems. Additionally, under reasonable assumptions on system matrices, these geometric programming problems can be further transformed into convex optimization problems. Simulation experiments validate the main results on a numerical example and epidemic spreading process example.
IEEE CONTROL SYSTEMS LETTERS
(2023)
Article
Automation & Control Systems
Zhiru Cao, Yugang Niu, James Lam
Summary: This article addresses the sliding mode control problem for a certain class of Markov jump systems subject to packet dropouts, and proposes a novel measurement model and solution based on Markov chain to improve the reliability and performance of the system.
IEEE TRANSACTIONS ON SYSTEMS MAN CYBERNETICS-SYSTEMS
(2023)
Article
Engineering, Electrical & Electronic
Shuying Qin, Jianping He, Chongrong Fang, James Lam
Summary: Differential privacy is a framework widely used for evaluating privacy loss in data anonymization. This study addresses the lack of research on discrete random mechanisms for discretely distributed data, and examines the primary conditions and properties of general discrete random mechanisms for differential privacy. The study also investigates the trade-off between data privacy and utility. Sufficient and necessary conditions for discrete epsilon-differential privacy are established, as well as sufficient conditions for discrete (epsilon,delta)-differential privacy. Closed-form expressions for differential privacy parameters are provided, and these conditions can be applied to evaluate the differential privacy properties of discrete noise-adding mechanisms with various types of noise. An optimal discrete epsilon-differential private noise-adding mechanism is proposed under the utility-maximization framework, where the utility is characterized by the similarity of the statistical properties between the mechanism's input and output. The findings suggest that the optimal class of discrete noise probability distributions in the mechanism is staircase-shaped.
IEEE TRANSACTIONS ON SIGNAL PROCESSING
(2023)
