Article
Automation & Control Systems
Yuan Sun, Peng Shi, Cheng-Chew Lim
Summary: This paper addresses the problem of leader-follower consensus fault-tolerant control for a class of nonlinear multi-agent systems with output constraints. The authors propose a new nonlinear state transformation function to deal with the asymmetric constraint on output. By integrating back-stepping and radial basis function neural network approaches, an adaptive consensus control framework is developed with a single parameter estimator, which reduces the computation of control algorithm compared to conventional adaptive approximation based control techniques. An adaptive compensation method is proposed to eliminate the effect of actuator failure. Under the proposed control scheme, all the closed-loop signals of the systems are bounded and the consensus tracking error converges to an adjustable small neighborhood of zero.
JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS
(2022)
Article
Engineering, Multidisciplinary
Kun-Peng Wang, Ze Tang, Ju H. Park, Jianwen Feng
Summary: This paper investigates the global and exponential quasi-consensus for a kind of nonlinear multi-agent systems with time-varying delay and stochastic disturbance. In light of the significant difficulty to precisely determine the impulsive sequence in advance, the conception of impulsive time window is introduced. The discrete Lyapunov function method is utilized to deal with the divided impulsive intervals caused by the impulsive time window. An effective distributed impulsive pinning (DIP) control strategy is proposed, which economizes the control execution time and saves the energy consumption. The paper derives sufficient conditions for quasi-consensus based on the parametric variation method and the extended delayed comparison principle. Additionally, the range of impulsive effects is further discussed by taking the positive and negative roles into consideration. Furthermore, the convergence rates and the consensus error levels corresponding to different impulsive effects are accurately calculated. Numerical examples are provided to illustrate the rationality of the main results.
IEEE TRANSACTIONS ON NETWORK SCIENCE AND ENGINEERING
(2022)
Article
Automation & Control Systems
Linna Wei, Yihao Liao, Shixian Luo, Wu-Hua Chen, Ganji Huang
Summary: This paper discusses the consensus problem of nonlinear multi-agent systems with nonuniform time-varying connection topologies through two novel distributed hybrid control protocols. By integrating intermittent control and impulsive control into a unified control framework using impulsive control with impulse time windows, it is more suitable for situations where only the time intervals in which impulses occur are known but the exact instants of impulses cannot be identified. The introduced intermittent impulsive control (IIC) reduces data transmission and enhances system security.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2023)
Article
Automation & Control Systems
Lili Zhang, Bing Chen, Chong Lin, Yun Shang
Summary: This paper addresses the finite-time consensus tracking control problem of nonlinear multi-agent systems by proposing a finite-time fuzzy adaptive consensus tracking protocol using fuzzy logic systems to approximate unknown nonlinear functions. The design scheme successfully overcomes singularity problems and ensures convergence of consensus tracking errors to a small neighborhood of the origin in finite time with bounded signals for multi-agent systems. The effectiveness of the proposed control protocol is verified through a numerical example.
INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE
(2021)
Article
Computer Science, Information Systems
Yang Liu, Huaguang Zhang, Qiaochu Li, Hongjing Liang
Summary: This paper presents a practical fixed-time bipartite consensus control framework for uncertain nonlinear multi-agent systems (MASs) by utilizing a barrier Lyapunov function (BLF) approach. The unknown nonlinearities of the MASs are addressed using the robustness of BLF instead of fuzzy logic systems/neural networks. A piecewise and differentiable function called the shift function is employed to avoid feasibility verification and allow arbitrary selection of initial states and pre-designation of settling time for bipartite consensus errors. The proposed control algorithm combines the shift function with BLF within the backstepping framework, ensuring the achievement of practical fixed-time bipartite consensus tracking and bounded signals in closed-loop systems for any initial state of MASs.
INFORMATION SCIENCES
(2022)
Article
Computer Science, Information Systems
Jiashu Dai, Chuanhai Yang, Xu Yan, Jiuru Wang, Kongwei Zhu, Chengdong Yang
Summary: This paper studies the application of semi-linear parabolic partial integro-differential equations with time delays in leaderless consensus of multi-agent systems (PIDEMASs). Consensus control of the leaderless PIDEMAS is achieved by utilizing information interaction and coordination among neighboring agents, and the consensus of the leaderless PIDEMAS is analyzed using the Lyapunov approach. Two sufficient conditions for consensus of the leaderless PIDEMAS are obtained by dealing with time-invariant delays and time-varying delays, respectively. Two examples are provided to illustrate the effectiveness of the developed theoretical results.
Article
Automation & Control Systems
Yi Niu, Yulong Yang, Ben Niu, Xudong Zhao, Lun Zhai, Boyi Zhang
Summary: This paper investigates the robust consensus tracking problem for heterogeneous nonlinear multi-agent systems with weighted communication graph and time-varying input delays. Intelligent technologies are used to approximate unknown quantities from neighbor systems and leader system, and adaptive controllers are designed using compensation system, double integral type and novel constructed exponential type Lyapunov-Krasovskii (L-K) functionals. The proposed control protocol achieves satisfactory control accuracy, and the computation and communication costs are efficiently reduced by using uniform hysteretic quantizer and dynamic surface filter.
IEEE TRANSACTIONS ON AUTOMATION SCIENCE AND ENGINEERING
(2023)
Article
Automation & Control Systems
Guoqiang Zhu, Haoqi Li, Xiuyu Zhang, Chenliang Wang, Chun-Yi Su, Jiangping Hu
Summary: This paper investigates an adaptive consensus output-feedback quantized control scheme for a class of high-order nonlinear multi-agent systems with input hysteresis. The proposed control scheme includes a hysteresis quantization inverse compensator, a barrier Lyapunov function, and a state constraint control strategy to eliminate the influence of hysteresis characteristics, maintain system states within a predetermined range, and allow for unknown parameters and disturbances.
IEEE-CAA JOURNAL OF AUTOMATICA SINICA
(2022)
Article
Mathematics, Interdisciplinary Applications
Youming Xin, Huiping Lyu, Huan Tuo, Zunshui Cheng
Summary: This paper considers the event-based consensus problem of third-order nonlinear multi-agent systems and proposes event-based controllers. Multi-agent systems with event-based controllers are regarded as nonlinear systems with disturbances. By a degenerate transformation, an error system is derived from multi-agent systems, and consensus for multi-agent systems is transformed into stability of the error system. Several sufficient conditions on event-based consensus are obtained based on Lyapunov theory and Kronecker product method. It is shown that multi-agent systems can achieve event-based consensus if the trigger parameter is sufficiently small and the control gain is sufficiently large under some simple conditions, and the Zeno behavior of the controllers is avoided. An example is presented to demonstrate the effectiveness of the derived results.
CHAOS SOLITONS & FRACTALS
(2023)
Article
Computer Science, Information Systems
Jing Zhang, Shuai Liu, Xianfu Zhang
Summary: This paper investigates the distributed consensus problem for a class of nonlinear multi-agent systems, using a uniform quantizer and observer to reduce communication burden and rebuild state information, proposing a distributed control protocol for achieving system consensus.
INFORMATION SCIENCES
(2022)
Article
Mathematics
Yunfeng Ji, Gang Wang, Qingdu Li, Chaoli Wang
Summary: This paper addresses the optimal consensus problems of a general heterogeneous nonlinear multi-agent system. A novel filter is proposed for each agent by integrating local gradients with neighboring output information. By using this filter and introducing an appropriate auxiliary variable, the event-triggered control algorithm is obtained within the framework of prescribed performance control. The algorithm has the remarkable property of saving resources by updating control signals only when necessary while achieving optimal consensus.
Article
Automation & Control Systems
Lei He, Wenhan Dong
Summary: The focus of this study is to address the consensus problem in heterogeneous nonlinear multi-agent systems. A distributed adaptive consensus controller is proposed, which utilizes only local information and employs the command filtered backstepping approach, as only some agents have direct access to reference information. Our proposed mechanism ensures the uniform and ultimate boundedness of all closed-loop signals, and it ensures the convergence of consensus tracking error to a small tunable compact set. Furthermore, the suggested control algorithm solves the formation-tracking problem of nonholonomic unmanned aerial vehicles.
Article
Automation & Control Systems
Hanfeng Li, Lihua Xie, Xianfu Zhang, Weihao Pan
Summary: This article focuses on the distributed consensus control problem for nonlinear multi-agent systems subject to sensor uncertainty. A new time-varying gain approach is proposed to achieve leader-follower consensus of nonlinear multi-agent systems and handle the unknown growth rate and uncertain sensor sensitivity.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2023)
Article
Automation & Control Systems
Jiaxi Chen, Junmin Li, Hongwei Jiao, Shuai Zhang
Summary: This paper investigates the globally fuzzy consensus of stochastic nonlinear multi-agent systems with hybrid-order dynamics. A new hybrid fuzzy consensus controller is designed for the followers based on the design method of fuzzy feed-forward compensator and Lyapunov stability theory. The proposed algorithm solves the consensus problem and achieves globally uniform ultimate bounded results.
Article
Mathematics, Applied
Juan Zhang, Huaguang Zhang, Yuliang Cai, Wei Wang
Summary: This paper investigates consensus problems for nonlinear multi-agent systems using distributed event-based control protocols. Both static and dynamic distributed control schemes are designed to achieve leader-follower and leaderless consensus problems, excluding Zeno behavior in MASs.
APPLIED MATHEMATICS AND COMPUTATION
(2021)
Article
Automation & Control Systems
Kevin D. D. Smith, Francesco Bullo
Summary: Strongly contracting dynamical systems and their adjoint systems are shown to have the same rate of contraction under time reversal. This duality leads to new convergence conditions for the Method of Successive Approximations (MSA) algorithm and establishes uniqueness of the optimal control and sufficiency of Pontryagin's minimum principle under certain assumptions.
IEEE CONTROL SYSTEMS LETTERS
(2023)
Article
Automation & Control Systems
Elizabeth Y. Huang, Dario Paccagnan, Wenjun Mei, Francesco Bullo
Summary: Tackling complex team problems requires understanding each team member's skills in order to devise a task assignment maximizing the team performance. This article proposes a novel quantitative model describing the decentralized process by which individuals in a team learn who has what abilities, while concurrently assigning tasks to each of the team members. We show that the appraisal states can be reduced to a lower dimension due to the presence of conserved quantities associated with the cycles of the appraisal network. Building on this, we provide rigorous results characterizing the ability, or inability, of the team to learn each other's skills and, thus, converge to an allocation maximizing the team performance. We complement our analysis with extensive numerical experiments.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Marco Coraggio, Saber Jafarpour, Francesco Bullo, Mario di Bernardo
Summary: Given a flow network with variable suppliers and fixed consumers, the minimax flow problem aims to minimize the maximum flow between nodes, subject to flow conservation and capacity constraints. In this study, we address this problem in a distributed manner by introducing the concept of consensus problem between the maximum downstream flows. Additionally, we propose a distributed algorithm to estimate these quantities. Finally, we apply these theoretical results to design an online distributed controller for preventing overcurrent in microgrids.
IEEE TRANSACTIONS ON CONTROL OF NETWORK SYSTEMS
(2023)
Article
Automation & Control Systems
Pedro Cisneros-Velarde, Francesco Bullo
Summary: In this article, a distributed algorithm is proposed for computing the Wasserstein barycenter of the initial measures in a multiagent system. The algorithm is based on stochastic, asynchronous, and pairwise exchange of information, and displacement interpolation in the Wasserstein space. The evolution of the algorithm is characterized and it is proven to compute the Wasserstein barycenter under various conditions. Two versions of the algorithm are introduced, one for computing a standard Wasserstein barycenter and the other for computing a randomized Wasserstein barycenter. The algorithm is further specialized to Gaussian distributions and its connection to opinion dynamics is explored.
IEEE TRANSACTIONS ON CONTROL OF NETWORK SYSTEMS
(2023)
Article
Cardiac & Cardiovascular Systems
Bishav Mohan, Gautam Singal, Adesh Kumar Singh, Bhupinder Singh, Ankur Singla, Juniali Hatwal, Aditya Uppal, Rohit Tandon, Gurbhej Singh, Abhishek Goyal, Shibba Takkar Chhabra, Naved Aslam, Ambuj Roy, Gurpreet Singh Wander, Akash Batta
Summary: The prevalence of lower extremity artery disease (LEAD) is increasing worldwide, especially in developing countries, leading to a rising number of lower limb amputations. Most patients with LEAD are unaware of their condition until late stages, making them vulnerable to limb-threatening complications unless actively screened and treated.
INDIAN HEART JOURNAL
(2023)
Article
Biochemistry & Molecular Biology
Yingying Jin, Matthew A. Downey, Ambuj Singh, Steven K. Buratto, Michael T. Bowers
Summary: Alzheimer's disease (AD) is an incurable disease causing memory loss, dementia, and death in the elderly. A beta protein aggregates, specifically dodecamers, play a crucial role in the formation of amyloid plaques in the brain. This study investigates the impact of three second-generation JPS small-molecule inhibitors on the formation of dodecamers and fibrils in A beta 42, with AC0201 being the most effective inhibitor.
ACS CHEMICAL NEUROSCIENCE
(2023)
Article
Automation & Control Systems
Saber Jafarpour, Alexander Davydov, Francesco Bullo
Summary: In this paper, we investigate the contractivity of monotone systems and the exponential convergence of positive systems using non-Euclidean norms. We introduce the concept of conic matrix measure as a framework to study stability of monotone and positive systems, and study its properties and its connection with weak pairings and standard matrix measures. By using conic matrix measures and weak pairings, we characterize the contractivity and incremental stability of monotone systems with respect to non-Euclidean norms. Moreover, we provide sufficient conditions for the exponential convergence of positive systems to their equilibria using conic matrix measures. We present novel results on the contractivity of excitatory Hopfield neural networks and the stability of interconnected systems using nonmonotone positive comparison systems.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Wenjie Liu, Jian Sun, Gang Wang, Francesco Bullo, Jie Chen
Summary: This article presents a data-driven model predictive control scheme for resilient control of linear time-invariant systems under denial-of-service attacks, achieving similar resilience as model-based control methods.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Computer Science, Hardware & Architecture
Victor Amelkin, Rakesh Vohra
Summary: To understand the impact of supply uncertainty on the structure of supply chain networks, a study is conducted in a setting where retailers and suppliers need to establish a costly relationship before engaging in trade. The study finds that retailers concentrate their links among a small number of suppliers due to insufficient diversification of the supply base.
Article
Automation & Control Systems
Anton V. Proskurnikov, Alexander Davydov, Francesco Bullo
Summary: This paper presents a novel nonpolynomial S-Lemma that provides constructive criteria for the existence of functions defined by weighted lp norms in the absolute stability of Lur'e-type systems. It introduces new absolute stability and absolute contractivity criteria, including a simple proof of the Aizerman and Kalman conjectures for positive Lur'e systems.
SIAM JOURNAL ON CONTROL AND OPTIMIZATION
(2023)
Article
Automation & Control Systems
Chiara Ravazzi, Francesco Bullo, Fabrizio Dabbene
Summary: This article explores how individuals' opinions evolve in modern society through continuous interactions and interpersonal influences. It proposes a mathematical model to study oligarchic influence systems and presents a data-driven approach to estimate social power.
IEEE TRANSACTIONS ON CONTROL OF NETWORK SYSTEMS
(2023)
Article
Automation & Control Systems
Gilberto Diaz-Garcia, Francesco Bullo, Jason R. Marden
Summary: Markov chains are increasingly being used for persistent robotic surveillance. The motivations for this choice are easy implementation, unpredictable surveillance patterns, and well-studied mathematics. However, applying previous results to scenarios with multiple agents can lead to intractable algorithms due to increased dimensionality.
IEEE CONTROL SYSTEMS LETTERS
(2023)
Article
Automation & Control Systems
Kevin D. Smith, Francesco Bullo
Summary: The basic reproduction number R0, which represents the typical number of secondary infections arising from a single infected individual, is characterized in this note by stability and geometric program descriptions. The geometric program characterization enables the transformation of R0-constrained and budget-constrained optimal resource allocation problems into convex optimization problems, allowing for efficient allocation of vaccines and antidotes. By targeting R0 instead of the spectral abscissa of the Jacobian matrix, different and potentially more effective solutions can be obtained.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Veronica Centorrino, Anand Gokhale, Alexander Davydov, Giovanni Russo, Francesco Bullo
Summary: This letter investigates the stability conditions of continuous-time Hopfield and firing-rate neural networks using contraction theory. It presents useful algebraic results on matrix polytopes and products of symmetric matrices. Sufficient conditions for strong and weak Euclidean contractivity of both models with symmetric weights and non-smooth activation functions are given. The contraction analysis leads to log-optimal contraction rates in almost all symmetric synaptic matrices. Finally, a firing-rate neural network model is proposed to solve a quadratic optimization problem with box constraints.
IEEE CONTROL SYSTEMS LETTERS
(2023)
Article
Automation & Control Systems
Robin Delabays, Francesco Bullo
Summary: This letter studies the celebrated Kuramoto-Sakaguchi model of coupled oscillators using two recent concepts, namely appropriately-defined subsets of the $n$-torus called winding cells and the semicontractivity of the model. The letter establishes the local semicontractivity of the Kuramoto-Sakaguchi model and characterizes the multistability of the model by proving the at most uniqueness of synchronous states within convex phase-cohesive subsets of winding cells. The sufficient conditions and estimates provided in this work are less conservative and more explicit than previous studies.
IEEE CONTROL SYSTEMS LETTERS
(2023)