Disturbance Observer-based Cluster Formation Control Of Multi-agent Systems

In the past ten years,the formation control of multi-agent systems has become a very challenging research topic in the cooperative research of multi-agent systems.In recent years,with the increasing demand for group formation,the value of researching cluster formation techniques is increasing.In the cluster formation problem,considering the diversity of the scales is also a subject of research significance and attractive prospects.In the modern industrial control system,there are inevitably disturbances and uncertainties.Therefore,the advanced control strategy with interference suppression has been paid much attention by scholars in recent years.It has played a significant role in improving the operational efficiency of the control system and improving the production efficiency of the actual engineering system.Therefore,it has wide practical application prospects.In this paper,two traditional nonlinear disturbance observer techniques are introduced,and a nonlinear constant disturbance observer and a nonlinear harmonic disturbance observer are studied firstly.The design framework of a general controller using disturbance observer-based control technology is proposed.The disturbance observer-based control algorithm for matched and mismatched disturbance and a disturbance observer-based sliding mode control algorithm for mismatched disturbance are also studied.Then,the nonlinear disturbance observer-based control method is applied to the cluster formation problem of multi-agent system.Firstly,the second-order multi-agent system under matched disturbances is studied.The agents in the system are divided into multiple clusters,and each cluster needs to maintain a predefined time-varying sub-formation.An observer is designed to identify the disturbances,and then the disturbance observer-based cluster formation protocol is proposed to ensure that the state of the agent in the same cluster implements a predefined time-varying sub-formation.Based on graph theory and Lyapunov method,the sufficient conditions for multi-agent system to achieve control objectives are given.Finally,the scale-based cluster formation problem of high-order multi-agent systemunder mismatched disturbances is studied.The agents in the system are divided into different clusters according to their scales,and there are huge differences between the scales.Distributed sliding mode control methods are proposed to solve the problem of cluster formation in leaderless case and leader-follower case.Firstly,an error-based identifier is designed to identify the disturbances,and then the scale-based sliding surface is designed.Based on the previous steps,a scale-based cluster formation control protocol is proposed.In addition,the Matlab numerical simulation platform is used to simulate the designed controller and the correctness of the proposed nonlinear disturbance observer-based control algorithm and cluster formation control algorithm for multi-agent systems is verified.