缺乏位置信息的视觉移动机器人leader-following编队控制

针对视觉移动机器人编队在缺乏位置信息情况下的控制问题,提出一种基于视觉的leader-following编队反馈控制方法。该方法利用leader标志物特征点在follower摄像机像平面上的坐标信息设计了观测器,对leader与follower间的相对位置进行估计,基于相对位置估计量与它们速度的关系,设计出leader-following编队反馈控制器,通过Lyapunov理论证明了闭环系统的稳定性。仿真结果表明,该控制方法能有效解决缺乏位置信息情况下视觉移动机器人编队的控制问题。

Leader-following多自主体系统时变编队跟踪控制

考虑时变时延,研究了高阶leader-following多自主体系统的分布式时变编队跟踪控制问题.针对连续高阶多自主体系统,设计了基于观测器的时变编队跟踪控制协议,通过状态变换,将系统的时变编队跟踪控制问题,转变为误差系统的稳定性问题.然后利用图论及李雅普诺夫稳定定理,研究了系统实现时变编队跟踪控制的充分条件,并且指出时变编队参考函数与时变时延无关.最后,数据仿真结果证明了所设计的协议能使follower自主体实现时变编队,并且跟踪leader自主体的轨迹.

Minimum-energy leader-following formation of distributed multiagent systems with communication constraints

This paper concerns minimum-energy leader-following formation design and analysis problems of distributed multiagent systems(DMASs)subjected to randomly switching topologies and aperiodic communication pauses.The critical feature of this paper is that the energy consumption during the formation control process is restricted by the minimum-energy constraint in the sense of the linear matrix inequality.Firstly,the leader-following formation control protocol is proposed based on the relative state information of neighboring agents,where the total energy consumption is considered.Then,minimum-energy leader-following formation design and analysis criteria are presented in the form of the linear matrix inequality,which can be checked by the generalized eigenvalue method.Especially,the value of the minimum-energy constraint is determined.An illustrative simulation is provided to show the effectiveness of the main results.

Leader-following多智能体网络分布式编队控制

针对多智能体固定拓扑网络,考虑无时延和有时延两种情况,研究了多智能体网络的分布式编队控制协议.首先,针对无通信时延的多智能体网络,提出了分布式编队控制协议,利用Lyapunov稳定理论,给出了协议有效的充分条件.然后,考虑时变通信时延,利用Lyapunov-Krasovskii函数证明了协议的有效性.最后,利用仿真实验证明了所设计协议的有效性.本文的创新点是对二阶多智能体网络设计分布式编队控制协议时考虑了速度一致性.

基于观测器的多智能体网络leader-following编队控制

主要研究了leader-following多智能体网络的分布式编队问题。假设多智能体网络中的每个follower不能实时得到leader的信息,针对每个follower设计相应的分布式观测器。考虑了无时延的切换拓扑多智能体网络和存在时变时延的固定网络两种情况。利用Lyapunov稳定定理,给出了系统稳定和控制协议有效的充分条件。最后,给出了数字仿真结果以验证所设计协议的有效性,即followers形成所要求的编队并且与leader达到速度一致。

Leader-following consensus protocols for formation control of multi-agent network

Two protocols are presented,which can make agents reach consensus while achieving and preserving the desired formation in fixed topology with and without communication timedelay for multi-agent network.First,the protocol without considering the communication time-delay is presented,and by using Lyapunov stability theory,the sufficient condition of stability for this multi-agent system is presented.Further,considering the communication time-delay,the effectiveness of the protocol based on Lyapunov-Krasovskii function is demonstrated.The main contribution of the proposed protocols is that,as well as the velocity consensus is considered,the formation control is concerned for multi-agent systems described as the second-order equations.Finally,numerical examples are presented to illustrate the effectiveness of the proposed protocols.

Robust Leader-Following Output Regulation of Uncertain Multi-Agent Systems With Time-Varying Delay

In this paper, the robust analysis and design of leader-following output regulation for multi-agent systems described by general linear models is given in presence of timevarying delay and model uncertainty. To this aim, a new regulation protocol for the closed-loop multi-agent system under a directed graph is proposed. An important specification of the proposed protocol is to guarantee the leader-following output regulation for uncertain multi-agent systems with both stable and unstable agents. Since many signals can be approximated by a combination of the stationary and ramp signals, the presented results work for adequate variety of the leaders. The analysis and design conditions are presented in terms of certain matrix inequalities. The method proposed can be used for both stationary and ramp leaders. Simulation results are presented to show the effectiveness of the proposed method.

Finite-time consensus for leader-following multi-agent systems over switching network topologies

Finite-time consensus problem of the leader-following multi-agent system under switching network topologies is studied in this paper. Based on the graph theory, matrix theory, homogeneity with dilation, and LaSalle＇s invariance principle, the control protocol of each agent using local information is designed, and the detailed analysis of the leader- following finite-time consensus is provided. Some examples and simulation results are given to illustrate the effectiveness of the obtained theoretical results.

Leader-following coordination of multi-agent systems with information feedback

Based on the strategy of information feedback from followers to the leader, flocking control of a group of agents with a leader is studied. The leader tracks a pre-defined trajectory and at the same time the leader uses the feedback information from followers to the leader to modify its motion. The advantage of this control scheme is that it reduces the tracking errors and improves the robustness of the team cohesion to followers＇ faults. The results of simulation are provided to illustrate that information feedback can improve the performance of the system.

Event-triggered leader-following formation control for multi-agent systems under communication faults: application to a fleet of unmanned aerial vehicles

The main contribution of this paper is the design of an event-triggered formation control for leader-following consensus in second-order multi-agent systems(MASs)under communication faults.All the agents must follow the trajectories of a virtual leader despite communication faults considered as smooth time-varying delays dependent on the distance between the agents.Linear matrix inequalities(LMIs)-based conditions are obtained to synthesize a controller gain that guarantees stability of the synchronization error.Based on the closed-loop system,an event-triggered mechanism is designed to reduce the control law update and information exchange in order to reduce energy consumption.The proposed approach is implemented in a real platform of a fleet of unmanned aerial vehicles(UAVs)under communication faults.A comparison between a state-of-the-art technique and the proposed technique has been provided,demonstrating the performance improvement brought by the proposed approach.

Reduced-Order Observer-Based Leader-Following Formation Control for Discrete-Time Linear Multi-Agent Systems

Formation control of discrete-time linear multi-agent systems using directed switching topology is considered in this work via a reduced-order observer, in which a formation control protocol is proposed under the assumption that each directed communication topology has a directed spanning tree. By utilizing the relative outputs of neighboring agents, a reduced-order observer is designed for each following agent. A multi-step control algorithm is established based on the Lyapunov method and the modified discrete-time algebraic Riccati equation. A sufficient condition is given to ensure that the discrete-time linear multi-agent system can achieve the expected leader-following formation.Finally, numerical examples are provided so as to demonstrate the effectiveness of the obtained results.

Leader-following consensus of discrete-time fractional-order multi-agent systems

Leader-following consensus of fractional order multi-agent systems is investigated. The agents are considered as discrete-time fractional order integrators or fractional order double-integrators. Moreover, the interaction between the agents is described with an undirected communication graph with a fixed topology. It is shown that the leader-following consensus problem for the considered agents could be converted to the asymptotic stability analysis of a discrete-time fractional order system. Based on this idea, sufficient conditions to reach the leader-following consensus in terms of the controller parameters are extracted. This leads to an appropriate region in the controller parameters space. Numerical simulations are provided to show the performance of the proposed leader-following consensus approach.

Leader-Following Consensus of Nonlinear Strict-Feedback Multi-agent Systems

The distributed leader-following consensus for nonlinear multi-agent systems in strict-feedback forms is investigated under directed topology. Firstly, each follower node is modeled by an integrator incorporating with nonlinear dynamics. The leader node is modeled as an autonomous nonlinear system which sends its information to one or more followers. Then, a simple and novel distributed protocol is proposed based only on the state feedback, under which the states of the followers ultimately synchronize to the leader. By using Lyapunov stability theorem and matrix theory, it is proved that the distributed leader-following consensus of nonlinear multi-agent systems with strict-feedback form is guaranteed by Lipschitz continuous control laws. Finally, some numerical simulations are provided to show the effectiveness of the developed method.

A cyberphysical-based approach to leader-following consensus for distributed multi-agent systems

This paper considers a leader-following consensus problem for first-order linear multi-agent systems with constant input and communication time-delays. Based on the idea of cyber physical systems, the use of control states of neighboring agents, a new distributed control protocol is presented. Furthermore, in terms of linear matrix inequalities, sufficient conditions of leader-following consensus for multi-agent systems with constant input, communication and input time-delays are presented respectively. Numerical simulations on multi-agent systems are presented to demonstrate the efficiency of the proposed criteria.

On the leader-following exponential consensus of discrete-time linear multi-agent systems over jointly connected switching networks

The leader-following asymptotic consensus problem for general discrete-time linear multi-agent systems over jointly con-nected switching networks was solved about a decade ago.Recently,the leader-following exponential consensus was further established using the so-called Krasovskii-LaSalle theorem for a class of discrete-time linear switched systems.But this method involves some advanced concepts such as the weak zero-state detectability of some limiting system.In this paper,we offer a simpler solution to the leader-following exponential consensus problem for general discrete-time linear multi-agent systems over jointly connected switching networks.After converting the solvability of the problem to the establishment of the exponential stability for a class of discrete-time linear switched systems,we first show that this class of linear switched systems is uniformly completely observable.Then,we further conclude that the uniform complete observability for this class of linear switched systems implies the exponential stability for the same class of linear switched systems,thus leading to the solution of the leader-following exponential consensus problem.Moreover,our approach also gives rise to an explicit characterization of the exponential convergence rate of the leader-following consensus problem.

Adaptive control for attitude coordination of leader-following rigid spacecraft systems with inertia parameter uncertainties

This paper studies the leader-following attitude coordination problems of multiple spacecraft in the presence of inertia parameter uncertainties. To achieve attitude coordination in the situation that even the leader's attitude is only applicable to a part of the following spacecraft, a nonlinear attitude observer is proposed to obtain an accurate estimation of the leader's attitude and angular velocity for all the followers. In addition, a distributed control scheme based on noncertainty equivalence principle is presented for multiple spacecraft' attitude synchronization. With a dynamic scaling, attitude consensus can be achieved asymptotically without any information of the bounds of the uncertain inertia parameters. Furthermore, once the estimations of inertia parameters reach their ideal values, the estimation process will stop and the ideal value of inertia parameter will be held. This is a special advantage of parameter estimation method based on non-certainty equivalence. Numerical simulations are presented to demonstrate that the proposed non-certainty equivalence-based method requires smaller control toque and converges faster compared with the certainty equivalence-based method.

Leader-Following Consensus of Multi-Agent Systems via Adaptive Event-Based Control

In this paper, the adaptive event-based control approach is applied to study leader-following consensus of multi-agent systems with linear dynamic models. Adaptive event-based controller and triggering function for each agent are designed, where the adaptive function is only dependent on its own event time instants. A sufficient condition on consensus is proposed, which shows that the adaptive event-based method presented in this paper not only can reduce the communication among neighboring agents, but also can determine the event time instants for each agent without using the global information. Furthermore, the Zeno-behavior for the concerned closed-loop system is excluded. Finally, an example is presented to ilhistratc the effectiveness of the obtained theoretical results.

Leader-following cooperative guidance law with specified impact time

The problem of guidance law is investigated for multiple interceptors to attack a target cooperatively.A leader-following cooperative guidance strategy is presented to render the leader and the followers reach the target at specified impact time.The guidance law of leader is given to meet the demand of specified impact time.The arrival time is synchronized by enforcing the ranges-to-go of followers keep consensus with that of leader.The convergence time bound is estimated without dependence on the initial states,since the proposed leader-following cooperative guidance law is fixed-time convergent.The simulation is developed to validate the availability of proposed cooperative guidance law.

Leader-following consensus of second-order nonlinear multi-agent systems subject to disturbances

In this study, we investigate the leader-following consensus problem of a class of heterogeneous secondorder nonlinear multi-agent systems subject to disturbances. In particular, the nonlinear systems contain uncertainties that can be linearly parameterized. We propose a class of novel distributed control laws, which depends on the relative state of the system and thus can be implemented even when no communication among agents exists. By Barbalat's lemma, we demonstrate that consensus of the second-order nonlinear multi-agent system can be achieved by the proposed distributed control law. The effectiveness of the main result is verified by its application to consensus control of a group of Van der Pol oscillators.

Finite-Time Consensus of a Leader-Following Multi-Agent Network with Non-Identical Nonlinear Dynamics and Time-Varying Topologies

In this paper, the finite-time consensus of a leader-following multi-agent network with non-identical nonlinear dynamics and time-varying topologies is investigated. All the agents, especially the leaders, have non-identical and nonlinear dynamics. According to the algebraic graph theory, Lyapunov stability theory and Kronecker product, a control strategy strategy is established to guarantee the finite-time consensus of multi-agent network with multiple leaders. Furthermore, several numerical simulations illustrate the effectiveness and feasibility of the proposed method.