This paper concentrates on the secure consensus problem of networked mechanical/Euler–Lagrange systems.First,a new periodic event-triggered(PET)secure distributed observer is proposed to estimate the leader informati...This paper concentrates on the secure consensus problem of networked mechanical/Euler–Lagrange systems.First,a new periodic event-triggered(PET)secure distributed observer is proposed to estimate the leader information.The proposed distributed observer only relies on the PET data from its neighbors,which can significantly reduce the communication and computational burden.More importantly,it is secure in the sense that it can work normally regardless of the Denial-of-Service(DoS)attacks.Second,based on the proposed distributed observer,an adaptive fuzzy control law is proposed for each Euler–Lagrange system.A PET mechanism is integrated into the controller,which can reduce the control update.This is helpful for both energy saving and fault tolerance of actuators.Moreover,the PET mechanism naturally makes the controller easy to be implemented in digital platform.The property of fuzzy logic systems and Gronwall inequality are skillfully utilized to show the stability of the closed-loop system.Finally,the proposed control scheme is verified on real Euler–Lagrange systems,which contain a robot manipulator and several servo motors.展开更多
Based on the idea of backstepping design, distributedcoordinated tracking problems under directed topology are discussedfor multiple Euler-Lagrange （EL） systems. The dynamicleader case is considered. First, with the...Based on the idea of backstepping design, distributedcoordinated tracking problems under directed topology are discussedfor multiple Euler-Lagrange （EL） systems. The dynamicleader case is considered. First, with the parameter-linearity property,a distributed coordinated adaptive control scheme is proposedfor EL systems in the presence of parametric uncertainties.Then, subject to nonlinear uncertainties and external disturbances,an improved adaptive control algorithm is developed by usingneural-network （NN） approximation of nonlinear functions. Bothproposed algorithms can make tracking errors for each followerultimately bounded. The closed-loop systems are investigated byusing the combination of graph theory, Lyapunov theory, and BarbalatLemma. Numerical examples and comparisons with othermethods are provided to show the effectiveness of the proposedcontrol strategies.展开更多
The tracking control for multiple Euler-Lagrange systems with external disturbances in finite time under undirected topology is investigated in this paper.A dynamic model is established for the multi-EL systems to acc...The tracking control for multiple Euler-Lagrange systems with external disturbances in finite time under undirected topology is investigated in this paper.A dynamic model is established for the multi-EL systems to accurately describe the general mechanical system.Furthermore,an integral terminal sliding mode surface is devised to converge the tracking errors of the system state to a neighborhood of zero within finite time,and the designed finite-time controller ensures fast convergence and high steady-state accuracy.To reduce the controller update frequency and network transmission communication load,a dynamic event-triggered mechanism is introduced between the sensor and controller,and no Zeno behavior was observed.Therefore,the Lyapunov stability theory and finite-time stability criterion prove that all signals in the closed-loop system are uniformly ultimately bounded in finite time.Finally,the simulation results verified the effectiveness of the proposed control method.展开更多
In this paper,a group consensus problem is investigated for multiple networked agents with parametric uncertainties where all the agents are governed by the Euler-Lagrange system with uncertain parameters.In the group...In this paper,a group consensus problem is investigated for multiple networked agents with parametric uncertainties where all the agents are governed by the Euler-Lagrange system with uncertain parameters.In the group consensus problem,the agents asymptotically reach several different states rather than one consistent state.A novel group consensus protocol and a time-varying estimator of the uncertain parameters are proposed for each agent in order to solve the couple-group consensus problem.It is shown that the group consensus is reachable even when the system contains the uncertain parameters.Furthermore,the multi-group consensus is discussed as an extension of the couple-group consensus,and then the group consensus with switching topology is considered.Simulation results are finally provided to validate the effectiveness of the theoretical analysis.展开更多
This paper studies global robust tracking of uncertain Euler-Lagrange systems with input disturbances.The authors develop a robust regulation-based approach for the problem.Specifically,by introducing a novel nonlinea...This paper studies global robust tracking of uncertain Euler-Lagrange systems with input disturbances.The authors develop a robust regulation-based approach for the problem.Specifically,by introducing a novel nonlinear internal model,the authors solve global asymptotic trajectory tracking with disturbance rejection of multiple step/sinusoidal signals with unknown amplitudes,frequencies,and phases.Moreover,the authors show that a robustness property to actuator noises can be guaranteed in a sense of strong integral input-to-state stability(iISS).That is,the closed-loop system is not only i ISS but also input-to-state stable(ISS)to small magnitude actuator noises.Furthermore,the authors explore a by-product overparametrized linear regression estimation,coming up with robust estimation of the unknown parameters.Finally,the authors present several numerical examples to illustrate the theoretical results.展开更多
A new automatic constraint violation stabilization method for numerical integration of Euler_Lagrange equations of motion in dynamics of multibody systems is presented. The parameters α,β used in the traditional con...A new automatic constraint violation stabilization method for numerical integration of Euler_Lagrange equations of motion in dynamics of multibody systems is presented. The parameters α,β used in the traditional constraint violation stabilization method are determined according to the integration time step size and Taylor expansion method automatically. The direct integration method, the traditional constraint violation stabilization method and the new method presented in this paper are compared finally.展开更多
This paper investigates the cooperative formation problem via impulsive control for a class of networked Euler–Lagrange systems. To reduce the energy consumption and communication frequency, the impulsive control met...This paper investigates the cooperative formation problem via impulsive control for a class of networked Euler–Lagrange systems. To reduce the energy consumption and communication frequency, the impulsive control method and cooperative formation control approach are combined. With the consideration of system uncertainties and communication delays among agents, neural networks-based adaptive technique is used for the controller design. Firstly, under the constraint that each agent interacts with its neighbors only at some sampling moments, an adaptive neural-networks impulsive formation control algorithm is proposed for the networked uncertain Euler–Lagrange systems without communication delays. Using Lyapunov stability theory and Laplacian potential function in the graph theory, we conclude that the formation can be achieved by properly choosing the constant control gains. Further, when considering communication delays,a modified impulsive formation control algorithm is proposed, in which the extended Halanay differential inequality is used to analyze the stability of the impulsive delayed dynamical systems. Finally, numerical examples and performance comparisons with continuous algorithm are provided to illustrate the effectiveness of the proposed methods.展开更多
基金supported by the National Natural Science Foundation of China(No.52375520)Hunan Provincial Natural Science Foundation Regional Joint Fund(2023JJ50037).
文摘This paper concentrates on the secure consensus problem of networked mechanical/Euler–Lagrange systems.First,a new periodic event-triggered(PET)secure distributed observer is proposed to estimate the leader information.The proposed distributed observer only relies on the PET data from its neighbors,which can significantly reduce the communication and computational burden.More importantly,it is secure in the sense that it can work normally regardless of the Denial-of-Service(DoS)attacks.Second,based on the proposed distributed observer,an adaptive fuzzy control law is proposed for each Euler–Lagrange system.A PET mechanism is integrated into the controller,which can reduce the control update.This is helpful for both energy saving and fault tolerance of actuators.Moreover,the PET mechanism naturally makes the controller easy to be implemented in digital platform.The property of fuzzy logic systems and Gronwall inequality are skillfully utilized to show the stability of the closed-loop system.Finally,the proposed control scheme is verified on real Euler–Lagrange systems,which contain a robot manipulator and several servo motors.
基金supported by the National Natural Science Foundation of China(6130400561174200)the Research Fund for the Doctoral Program of Higher Education of China(20102302110031)
文摘Based on the idea of backstepping design, distributedcoordinated tracking problems under directed topology are discussedfor multiple Euler-Lagrange （EL） systems. The dynamicleader case is considered. First, with the parameter-linearity property,a distributed coordinated adaptive control scheme is proposedfor EL systems in the presence of parametric uncertainties.Then, subject to nonlinear uncertainties and external disturbances,an improved adaptive control algorithm is developed by usingneural-network （NN） approximation of nonlinear functions. Bothproposed algorithms can make tracking errors for each followerultimately bounded. The closed-loop systems are investigated byusing the combination of graph theory, Lyapunov theory, and BarbalatLemma. Numerical examples and comparisons with othermethods are provided to show the effectiveness of the proposedcontrol strategies.
基金supported by the National Natural Science Foundation of China(Grant Nos.62121004,62033003,62003098,62103111,and 62303125)the Local Innovative and Research Teams Project of Guangdong Special Support Program(Grant No.2019BT02X353)+2 种基金the China Postdoctoral Science Foundation(Grant Nos.2021TQ0079 and 2021M700883)the Natural Science Foundation of Guangdong Province(Grant Nos.2023A1515011527 and 2022A1515011506)the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2023A1515010855 and 2022A1515110949)。
文摘The tracking control for multiple Euler-Lagrange systems with external disturbances in finite time under undirected topology is investigated in this paper.A dynamic model is established for the multi-EL systems to accurately describe the general mechanical system.Furthermore,an integral terminal sliding mode surface is devised to converge the tracking errors of the system state to a neighborhood of zero within finite time,and the designed finite-time controller ensures fast convergence and high steady-state accuracy.To reduce the controller update frequency and network transmission communication load,a dynamic event-triggered mechanism is introduced between the sensor and controller,and no Zeno behavior was observed.Therefore,the Lyapunov stability theory and finite-time stability criterion prove that all signals in the closed-loop system are uniformly ultimately bounded in finite time.Finally,the simulation results verified the effectiveness of the proposed control method.
基金supported by the National Natural Science Foundation of China under Grant Nos.60974017.61273212,61322302,61104145,and 61004097Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ14F030011+2 种基金the Natural Science Foundation of Jiangsu Province of China under Grant No.BK2011581the Research Fund for the Doctoral Program of Higher Education of China under Grant No.20110092120024the Fundamental Research Funds for the Central Universities of China
文摘In this paper,a group consensus problem is investigated for multiple networked agents with parametric uncertainties where all the agents are governed by the Euler-Lagrange system with uncertain parameters.In the group consensus problem,the agents asymptotically reach several different states rather than one consistent state.A novel group consensus protocol and a time-varying estimator of the uncertain parameters are proposed for each agent in order to solve the couple-group consensus problem.It is shown that the group consensus is reachable even when the system contains the uncertain parameters.Furthermore,the multi-group consensus is discussed as an extension of the couple-group consensus,and then the group consensus with switching topology is considered.Simulation results are finally provided to validate the effectiveness of the theoretical analysis.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.61673216 and 62073168supported by the China Scholarship Council on his study at the University of Groningen,The Netherlandspartially done when he was with the School of Automation,Nanjing University of Science and Technology,Nanjing 210094,China。
文摘This paper studies global robust tracking of uncertain Euler-Lagrange systems with input disturbances.The authors develop a robust regulation-based approach for the problem.Specifically,by introducing a novel nonlinear internal model,the authors solve global asymptotic trajectory tracking with disturbance rejection of multiple step/sinusoidal signals with unknown amplitudes,frequencies,and phases.Moreover,the authors show that a robustness property to actuator noises can be guaranteed in a sense of strong integral input-to-state stability(iISS).That is,the closed-loop system is not only i ISS but also input-to-state stable(ISS)to small magnitude actuator noises.Furthermore,the authors explore a by-product overparametrized linear regression estimation,coming up with robust estimation of the unknown parameters.Finally,the authors present several numerical examples to illustrate the theoretical results.
文摘A new automatic constraint violation stabilization method for numerical integration of Euler_Lagrange equations of motion in dynamics of multibody systems is presented. The parameters α,β used in the traditional constraint violation stabilization method are determined according to the integration time step size and Taylor expansion method automatically. The direct integration method, the traditional constraint violation stabilization method and the new method presented in this paper are compared finally.
基金supported by the National Natural Science Foundation of China(Grant Nos.61304005,61403103,61673135,and 61603114)
文摘This paper investigates the cooperative formation problem via impulsive control for a class of networked Euler–Lagrange systems. To reduce the energy consumption and communication frequency, the impulsive control method and cooperative formation control approach are combined. With the consideration of system uncertainties and communication delays among agents, neural networks-based adaptive technique is used for the controller design. Firstly, under the constraint that each agent interacts with its neighbors only at some sampling moments, an adaptive neural-networks impulsive formation control algorithm is proposed for the networked uncertain Euler–Lagrange systems without communication delays. Using Lyapunov stability theory and Laplacian potential function in the graph theory, we conclude that the formation can be achieved by properly choosing the constant control gains. Further, when considering communication delays,a modified impulsive formation control algorithm is proposed, in which the extended Halanay differential inequality is used to analyze the stability of the impulsive delayed dynamical systems. Finally, numerical examples and performance comparisons with continuous algorithm are provided to illustrate the effectiveness of the proposed methods.
