Distributed Time-Varying Formation Tracking Analysis and Design for Second-Order Multi-Agent Systems

Distributed time-varying formation tracking analysis and design problems for second-order multi-agent systems with one leader are studied respectively, where the states of followers form a predefined time-varying formation while tracking the state of the leader. Different from the previous results on formation tracking control, the formation for the followers can be described by specified time-varying vectors and the trajectory of the leader can also be time-varying. A distributed formation tracking protocol is constructed using only neighboring relative information. Necessary and sufficient conditions for second-order multi-agent systems with one leader to achieve time-varying formation tracking are proposed by utilizing the properties of the Laplacian matrix, where the formation tracking feasibility constraint is also given. An approach to design the formation tracking protocol is proposed by solving an algebraic Riccati equation. The presented results can be applied to deal with the target enclosing problems and consensus tracking problems for second-order multi-agent systems with one target/leader. An application in the target enclosing of multiple vehicles is provided to demonstrate the effectiveness of the theoretical results.     

Mean Square Bipartite Consensus for Multi-agent Systems with Measurement Noises and Communication Time-delays

International Journal of Control, Automation and Systems - This paper investigates the mean square bipartite consensus problem of a multi-agent system with considering measurement noises and...     

具有随机量测噪声的变结构控制

本文研究了一种考虑状态量测噪声的变结构控制，提出了随机超平面的概念。分别以随机噪声的导数有界与无界情况设计出了控制律，并估计出随机超平面的方差界。     

具有时滞的二阶多智能体系统的一致性分析

多智能体系统是由多个自主的智能体组成的集合,实现协调合作的首要条件就是各个多智能体达到一致.本文应用频域分析法研究了具有时滞的二阶定拓扑多智能体系统的一致性问题,得到了保证所有智能体状态达到一致的充分必要条件,并且给出了系统最大容许时滞与定拓扑图的Laplacian矩阵特征值之间的关系.最后,通过数值仿真验证了所得结论的有效性.     

Accuracy of Construction of Approximating Models under Bounded Measurement Noises

If the output of a system is measured under an additive noise with predefined set-valued estimate, then there is an optimal size for the vector of parameters of the approximating model under which the guaranteed approximation error is minimal. This result is extended to the case in which the a priori noise estimate depends on the measured parameter.__________Translated from Avtomatika i Telemekhanika, No. 5, 2005, pp. 125–133.Original Russian Text Copyright © 2005 by Kuntsevich.     

Polynomial Design of Optimal Sampled-Data Tracking Systems I. Quadratic Optimization

A method of optimal design of digital tracking systems for continuous-time plants is presented. The method is based on the use of Laplace transformation in continuous time and polynomial equation theory. The cost function employed for quadratic optimization takes system performance in continuous time into account. The structure of optimal digital controller transfer function is investigated and its order is determined explicitly. The possibility of designing optimal tracking system for a neutral plant is analyzed.     

Consensus of Multi-Agent Systems With Diverse Input and Communication Delays

The consensus problem for multi-agent systems with input and communication delays is studied based on the frequency-domain analysis. Two decentralized consensus conditions are obtained, one of which is given for the systems based on undirected graphs with diverse input delays and the other is for the systems based on directed graphs with diverse communication delays and input delays. For the systems with both communication delays and input delays, the consensus condition is dependent on input delays but independent of communication delays.     

Polynomial Design of Optimal Sampled-Data Tracking Systems: II. Robust Optimization

A direct method for robust sampled-data tracking systems design is presented. The method is based on the use of Laplace transformation in continuous time and polynomial equation theory. A criterion is proposed for robust optimization of sampled-data tracking systems. The structure of the optimal robust controller transfer function is investigated and its order is determined explicitly. The relations between robust and quadratic optimization problems are established. A mixed optimization problem is considered, when the cost function includes the integral quadratic error and a robustness term.     

Consensus Based Formation Control and Trajectory Tracing of Multi-Agent Robot Systems

Multi-Agent Robot Systems (MARS) are, nowadays, an important research area within robotics and Artificial Intelligence. A growing number of systems have been presented in the literature recently. This paper develops a general method of controller design for formation keeping and motion trajectory tracing of the MARS. A novel motion model about the motion trajectory tracing and group formation control of MARS for fixed and changing interaction is presented. Based on this model and the consensus theory, two theorems about the condition of mobile stability properties of the system are analyzed and proved. Finally, the validity of this scheme is supported by computer simulation. Supported by the National Natural Science Foundation of China under Grants 60573005 and 60603006.     

多智能体系统跟踪领导节点的随机一致性问题研究

针对一阶连续时间多智能体系统,研究了在带有通信噪声情况下跟踪领导节点的随机一致性问题。将代数图理论、矩阵理论和随机Lyapunov方法相结合,给出了在领导节点状态的一阶导数有界的情况下,系统达到随机一致的条件,并给出了误差均方期望上界的表达式。通过研究该误差上界表达式,可以找到控制误差上界的关键参数。其中分别研究了系统中所有个体都可以获取领导节点信息和只有一部分个体可以获取领导节点信息的两种情形。第二种情形更接近实际情况,也有更大的研究价值。最后通过仿真实验证明:理论推导与仿真结果相一致。     

Predictor Feedback Stabilization of Stochastic Linear Delayed Systems with Both Additive and Multiplicative Noises

In this paper we investigate memory control of stochastic linear delayed systems with both additive and multiplicative noises. A new formula is first presented to obtain the prediction vector from the system dynamics and then it is used for feedback to reduce the input delay in the original delayed system. To ensure the stability of closed‐loop system, some matrix inequality conditions are given that in the case of feasibility provide the stabilizing gain of the predictor controller. The proposed method is applied to stochastic quarter‐car model of an active suspension system to show the effectiveness of the approach.     

Model Predictive Control Schemes for Consensus in Multi-Agent Systems with Single- and Double-Integrator Dynamics

In this paper, we address the problem of driving a group of agents towards a consensus point when the agents have a discrete-time single- or double-integrator dynamics and the communication network is time-varying. We propose decentralized model predictive control schemes that take into account constraints on the agents' input and show that they guarantee consensus under mild assumptions. Since the global cost does not decrease monotonically, it cannot be used as a Lyapunov function for proving convergence to consensus. For this reason, our proofs exploit geometric properties of the optimal path followed by individual agents.      

Consensus of Multi-Agent Systems in Directed Networks With Nonuniform Time-Varying Delays

In this note, we study consensus problems for continuous-time multi-agent systems in directed networks with dynamically changing topologies and nonuniform time-varying delays. We have analyzed consensus problems in the following three cases: 1) directed networks with dynamically changing topologies and nonuniform time-varying delays; 2) directed networks with intermittent communication and data packet dropout; and 3) finite-time consensus in directed networks with dynamically changing topologies and nonuniform time-varying delays. We propose a new approach based on a tree-type transformation to investigate consensus problems in all three cases. Some necessary and/ or sufficient conditions are established. Simulation results are also given to demonstrate the theoretical results.      

Global FLS-based Consensus of Stochastic Uncertain Nonlinear Multi-agent Systems

Using graph theory,matrix theory,adaptive control,fuzzy logic systems and other tools,this paper studies the leader-fol-lower global consensus of two kinds of s...     

Asynchronous Consensus in Continuous-Time Multi-Agent Systems With Switching Topology and Time-Varying Delays

The paper studies asynchronous consensus problems of continuous-time multi-agent systems with discontinuous information transmission. The proposed consensus control strategy is implemented based on the state information of each agent's neighbors at some discrete times. The asynchrony means that each agent's update times, at which the agent adjusts its dynamics, are independent of others'. Furthermore, it is assumed that the communication topology among agents is time-dependent and the information transmission is with bounded time-varying delays. If the union of the communication topology across any time interval with some given length contains a spanning tree, the consensus problem is shown to be solvable. The analysis tool developed in this paper is based on nonnegative matrix theory and graph theory. The main contribution of this paper is to provide a valid distributed consensus algorithm that overcomes the difficulties caused by unreliable communication channels, such as intermittent information transmission, switching communication topology, and time-varying communication delays, and therefore has its obvious practical applications. Simulation examples are provided to demonstrate the effectiveness of the theoretical results.     

具有随机丢包的网络化多自主体系统的一致性

研究具有随机丢包的网络化多自主体系统的均方一致性问题,其中不同自主体间的通信通道具有相同的丢包情况并且均服从马尔可夫(Markov)分布。首先,利用系统变换和迭代方法,得到了系统达到均方一致的一个初等充要条件。然后,利用矩阵理论和图论知识,如果拓扑图含有有向生成树,则可以将系统的均方一致性转化成一个线性Markov跳变系统的均方稳定性,并且可以建立线性矩阵不等式形式的均方可镇定准则。最后,通过相应的仿真实例说明了所得结论的可行性。     

The Auxiliary Model Based Hierarchical Estimation Algorithms for Bilinear Stochastic Systems with Colored Noises

International Journal of Control, Automation and Systems - This paper considers the parameter identification for a class of nonlinear stochastic systems with colored noise. An input-output...     

基于社区分解的多智能体递阶一致性仿真研究

在多智能体系统的收敛速度一致性问题的研究中,传统的一致性算法一般都是在单层拓扑结构上讨论的.在设计边权数或者调整连接边实现提高系统的一致性收敛速度的过程中,针对类似的方法在很多情况下是受限制的.为了解决上述问题,提出一种社区分解的递阶一致性算法,采用社区分解方法对多智能体拓扑结构优化分解,进而将多智能体系统单层一致性问题转化为多层一致性问题,在维持原有拓扑结构约束的情况下提高系统的一致性收敛速度.针对一阶线性系统,通过与标准一致性算法的仿真比较,验证了改进算法的有效性.     

A New Consensus Algorithm for Multi-Agent Systems via Decentralized Dynamic Output Feedback

In this paper, we study a consensus problem for multi-agent systems via dynamic output feedback control. The entire system is decentralized in the sense that each agent can only obtain output information from its neighbor agents. For practical purpose, we assume that actuator limitation exists, and require that the consensus be achieved among the agents at a specified convergence rate. By using an appropriate coordinate transformation, we reduce the consensus problem on hand to solving a strict matrix inequality, and then propose to use the homotopy based method for solving the matrix inequality. It turns out that our algorithm includes the existing graph Laplacian based algorithm as a special case.     

Bounded Consensus Algorithms for Multi‐Agent Systems in Directed Networks

In this paper, the consensus problem is investigated via bounded controls for the multi‐agent systems with or without communication. Based on the nested saturation method, the saturated control laws are designed to solve the consensus problem. Under the designed saturated control laws, the transient performance of the closed‐loop system can be improved by tuning the saturation level. First of all, asymptotical consensus algorithms with bounded control inputs are proposed for the multi‐agent systems with or without communication delays. Under these consensus algorithms, the states’ consensus can be achieved asymptotically. Then, based on a kind of novel nonlinear saturation functions, bounded finite‐time consensus algorithms are further developed. It is shown that the states’ consensus can be achieved in finite time. Finally, two examples are given to verify the efficiency of the proposed methods.