Distributed tracking control of second-order multi-agent systems under measurement noises

This paper considers a leader-following tracking control problem for second-order multiagent systems（MASs） under measurement noises and directed communication channels.It is assumed that each follower-agent can measure the relative positions and velocities of its neighbors in a noisy environment.Based on a novel velocity decomposition technique,a neighbor-based control law is designed to realize local control strategies for these continuous-time agents.It is shown that the proposed consensus protocol can guarantee that all the follower-agents track the active leader.In addition,this result is extended to a more general case with switching topologies.Finally,a numerical example is given for illustration.     

单边Lipschitz非线性多智能体系统一致性追踪控制

针对单边Lipschitz非线性多智能体系统,提出了一种分布式一致性控制方法.首先,构建了领导-跟随者动力学结构,用于实现单边Lipschitz多智能体系统的追踪控制.然后,设计了单边Lipschitz非线性多智能体系统的一致性控制协议,可根据智能体之间局部交互信息构建分布式反馈控制,并将系统的一致性追踪问题转化为系统...     

Consensus control design for multi-agent systems using relative output feedback

This paper studies the consensus problem of multi-agent systems in which all agents are modeled by a general linear system. The authors consider the case where only the relative output feedback between the neighboring agents can be measured. To solve the consensus problem, the authors first construct a static relative output feedback control under some mild constraints on the system model. Then the authors use an observer based approach to design a dynamic relative output feedback control. If the adjacent graph of the system is undirected and connected or directed with a spanning tree, with the proposed control laws, the consensus can be achieved. The authors note that with the observer based approach, some information exchange between the agents is needed unless the associated adjacent graph is completely connected.     

Consensus design for continuous-time multi-agent systems with communication delay

This paper investigates a consensus design problem for continuous-time first-order multiagent systems with uniform constant communication delay.Provided that the agent dynamic is unstable and the diagraph is undirected,sufficient conditions are derived to guarantee consensus.The key technique is the adoption of historical input information in the protocol.Especially,when agent＇s own historical input information is used in the protocol design,the consensus condition is constructed in terms of agent dynamic,communication delay,and the eigenratio of the network topology.Simulation result is presented to validate the effectiveness of the theoretical result.     

异质多自主体系统的一致性

研究由一阶自主体和二阶自主体构成的异质多自主体系统的一致性问题.考察连接拓扑为固定有向图的异质多自主体系统在无时延静态一致性算法下的收敛问题,利用图论和矩阵分析方法得到了系统渐近收敛一致的充要条件;在假设连接拓扑在有向连通图之间动态切换条件下,分别研究领导-跟随连接拓扑和无领导连接拓扑下异质多自主体系统的静态一致性问题,并采用Lyapunov定理和线性矩阵不等式得到了系统在具有时变输入时延的一致性算法作用下渐近收敛一致的时延依赖条件.最后,仿真结果验证了结论的正确性.     

时滞多智能体系统关于参考状态的信息一致性

研究了具有参考状态的有向通信时延多智能体系统的信息一致性问题.提出了适用于可连续通信并有通信时延的有向多智能体系统关于参考状态的一致性算法,严格推导了多智能体系统在该算法作用下达到信息一致性的充分性判据,最后以水下无人航行器协同作战为背景,仿真验证了所提出的一致性算法和判据的有效性.     

多智能体系统的有限时间跟踪控制

基于领导-跟随者模型研究了多智能体系统的有限时间跟踪控制问题。针对领导者状态是时变的情况,提出了一类非线性有限时间跟踪控制算法,在固定网络拓扑结构下,利用Lyapunov有限时间稳定性理论和矩阵理论分析,得到了该算法使得系统中跟随者状态在有限时间内与领导者状态达到一致的充分条件;在切换网络拓扑结构下,提出了一类有限时间跟踪控制算法,在领导者的状态是时不变的情况下,给出了该算法使得系统实现有限时间跟踪控制的充分条件。仿真实例验证了所提出两类算法的有效性。     

Consensus problem of second-order multi-agent systems with time-varying communication delay and switching topology

Leader-following stationary consensus problem is investigated for the second-order multi-agent systems with timevarying communication delay and switching topology.Based on Lyapunov-Krasovskii functional and Lyapunov-Razumikhin functions respectively,consensus criterions in the form of linear matrix inequality (LMI) are obtained for the system with time-varying communication delays under static interconnection topology converging to the leader’s states.Moreover,the delay-dependent consensus criterion in the form of LMI is also obtained for the system with time-invariant communication delay and switching topologies by constructing Lyapunov-Krasovskii functional.Numerical simulations present the correctness of the results.     

具有混合执行器故障的多智能体分布式有限时间自适应协同容错控制

针对多智能体编队系统执行器发生故障时,所引起的参数不确定以及系统瞬态不稳定问题,本文采用径向基函数神经网络(radial basis function neural networks, RBFNNs)对不确定参数(未知函数)进行估计。同时,基于反推技术设计出合理的自适应容错控制器,并通过有限时间理论保证系统实现瞬态稳定。首先,本文采用10个智能体作为被控对象,基于有向通讯拓扑结构理论,构建了非线性多智能体系统模型。其次,基于RBFNNs逼近特性,采用反推技术与动态面技术相结合,设计出合理的容错控制器,补偿多智能体中出现的未知非线性执行器故障,并采用有限时间理论解决系统瞬态不稳定问题。接着,基于Lyapunov稳定性理论分析了控制器的稳定性和快速收敛性。最后,通过两种算例对比,验证了所设计的控制器性能优于传统的反推技术,为工程实践提供了一种有效的研究思路。     

Robust iterative learning control for nonlinear systems with measurement disturbances

The iterative learning control (ILC) has been demon-strated to be capable of considerably improving the tracking perfor-mance of systems which are affected by the iteration-independent disturbance. However, the achievable performance is greatly degraded when iteration-dependent, stochastic disturbances are pre-sented. This paper considers the robustness of the ILC algorithm for the nonlinear system in presence of stochastic measurement disturbances. The robust convergence of the P-type ILC algorithm is firstly addressed, and then an improved ILC algorithm with a decreasing gain is proposed. Theoretical analyses show that the proposed algorithm can guarantee that the tracking error of the nonlinear system tends to zero in presence of measurement dis-turbances. The analysis is also supported by a numerical example.     

相关量测噪声情况下多传感器集中式融合跟踪

在实际的多传感器融合目标跟踪中,各传感器之间的量测噪声往往是相关的。对于量测噪声相关的多传感器量测,利用Cholesky分解和单位下三角阵的求逆方法,将其转化为量测噪声互不相关的等价的多传感器伪量测,然后基于Kalman滤波,提出了一种解决量测噪声相关情况下多传感器融合目标跟踪问题的新算法。与已有的和直接利用原始传感器量测的集中式融合算法相比,三者在计算精度上完全等价,但新算法的计算复杂度却大大降低。数值仿真实验进一步验证了新算法的有效性。     

Fast consensus seeking for multi-agent systems

For multi-agent systems based on the local information,the agents automatically converge to a common consensus state and the convergence speed is determined by the algebraic connectivity of the communication network.To study fast consensus seeking problems of multi-agent systems in undirected networks,a consensus protocol is proposed which considers the average information of the agents’ states in a certain time interval,and a consensus convergence criterion for the system is obtained.Based on the frequency-domain analysis and algebra graph theory,it is shown that if the time interval is chosen properly,then requiring the same maximum control effort the proposed protocol reaches consensus faster than the standard consensus protocol.Simulations are provided to demonstrate the effectiveness of these theoretical results.     

Sliding mode fault tolerant consensus control for multi-agent systems based on super-twisting observer

The fault-tolerant consensus problem for leader-following nonlinear multi-agent systems with actuator faults is mainly investigated. A new super-twisting sliding mode observer is constructed to estimate the velocity and undetectable fault information simultaneously. The time-varying gain is introduced to solve the initial error problem and peak value problem, which makes the observation more accurate and faster. Then, based on the estimated results, an improved sliding mode fault-tolerant consen...     

Self-tuning measurement fusion white noise deconvolution estimator with correlated noises

For the multisensor linear discrete time-invariant stochastic systems with correlated noises and unknown noise statistics, an on-line noise statistics estimator is presented by using the correlation method. Substituting it into the steady-state Riccati equation, the self-tuning Riccati equation is obtained. Using the Kalman filtering method, based on the self-tuning Riccati equation, a self-tuning weighted measurement fusion white noise deconvolution estimator is presented. By the dynamic error system analysis (DESA) method, it is proved that the self-tuning fusion white noise deconvolution estimator converges to the optimal fusion steadystate white noise deconvolution estimator in a realization, so that it has the asymptotic global optimality. A simulation example for Bernoulli-Gaussian input white noise shows its effectiveness.     

Data-based predictive control for networked nonlinear systems with packet dropout and measurement noise

In this paper, the data-based control problem is investigated for a class of networked nonlinear systems with measurement noise as well as packet dropouts in the feedback and forward channels. The measurement noise and the number of consecutive packet dropouts in both channels are assumed to be random but bounded. A data-based networked predictive control method is proposed, in which a sequence of control increment predictions are calculated in the controller based on the measured output error, and based on the control increment predictions received by the actuator, a proper control action is obtained and applied to the plant according to the real-time number of consecutive packet dropouts at each sampling instant. Then the stability analysis is performed for the networked closedloop system. Finally, the effectiveness of the proposed method is illustrated by a numerical example.     

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.     

一类离散时间异构多智能体系统有向图下的一致性分析

研究了离散时间一阶二阶混合的异构多智能体系统有向通信下的一致性问题。首先,对该系统内的个体分别提出了相应的一致性协议。针对该异构系统不满足离散时间系统研究中凸性要求的问题,本文引入了一个非奇异变换,采用非负矩阵理论和一致性理论,分别分析得出了系统在固定和动态拓扑下实现一致性的充分条件。当通信拓扑包含生成树,采样时间和控制参数在一定范围内取值系统将获得一致性,该范围取决于通信拓扑的度矩阵。最后,通过仿真对该结论进行了验证。     

Consensus and r-consensus problems for singular systems

In this paper, the problem of consensus for continuous time singular systems of multi-agent networks is considered. The definition of r-consensus is introduced for singular systems of multi-agent networks. Firstly, linear systems with algebraic constraints are considered, and the corresponding results about consensus and average-consensus are derived. Then r-consensus and consensus problems of singular systems are investigated. Sufficient conditions of r-consensus and consensus are obtained, respectively. Finally, an illustrative example is given to show the effectiveness of the proposed method.     

Target aggregation of second-order multi-agent systems with switching interconnection

In this paper,the target aggregation is investigated for a multi-agent system consisting of second-order agents and multiple leaders.Sufficient conditions are proposed to make the agents approach the target set spanned by these moving leaders.With the condition on switching interconnection topologies,all mobile agents can asymptotically track the dynamical target set specified by multiple moving leaders with bounded error.Moreover,discussion on the case with static leaders is also given.     

带相关噪声的加权观测融合估计算法及其全局最优性

针对多传感器线性离散定常随机控制系统,当具有相关噪声且每个传感器带不同观测阵时,基于矩阵满秩分解与加权最小二乘理论,提出了新的加权观测融合估计算法。该算法首先将多个传感器的观测折算到一个等效的传感器上,对等效的传感器系统进行估计,证明了其估计结果相同于集中式融合稳态Kalman估计结果,因而它同样具有渐近全局最优性,且可明显减小计算负担,便于实时应用。仿真实验结果表明了该算法的有效性。