Coordinated Path Following Control Of Nonholonomic Mobile Robots With Prescribed Performance

With the continuous expansion of the application field of robots,people have increasingly higher requirements for the control performance of mobile robots,including the transient performance and steady-state performance.This means the controller design of mobile robots has to satisfy the prescribed performance.At the same time,because the application scenarios become more and more complex and the tasks are more and more,multiple mobile robots with a certain formation pattern will be more efficient and stronger to obtain environmental information when they complete complex and dangerous tasks.Therefore,the design of coordinated controllers for mobile robots with prescribed performance is a very challenging and hot research topic in the control field.This thesis focuses on the coordinated path following control of nonholonomic mobile robots with prescribed performance.Specifically,for mobile robots with nonholonomic constraint,on the basis of the prescribed performance of each mobile robot,the coordinated path following control schemes are proposed for nonholonomic mobile robots subject to the same reference path and multiple reference paths,respectively.The specific contents are summarized as follows.Firstly,the x axis direction error and the y axis direction error are combined into a distance error,which establishes the novel error equation and solves the underactuated problem of the mobile robot.To make each robot satisfy the prescribed performance,the novel tan-type barrier Lyapunov function is used to deal with path following errors.By guaranteeing the boundedness of the tan-type barrier Lyapunov function,the performance function is adjusted to keep the path following errors in the predefined region and make each mobile robot satisfy the prescribed performance.Secondly,the coordinated control problem is considered for multiple mobile robots subject to the same parameterized path on the basis of maintaining the prescribed performance of each mobile robot.By combining the graph theory method and the leader-follower method,the coordinated formation controller is designed to make multiple mobile robots divide the path parameter interval between two virtual leaders equally and maintain the formation pattern on the same parameterized path by using the path variable information from its neighbor.Finally,the coordinated control problem is considered for the multiple mobile robots with multiple parameterized paths on the basis of maintaining the prescribed performance of each mobile robot.By combining the graph theory method and the leader-follower method,the coordinated formation controller is designed to guarantee the collision avoidance and make multiple mobile robots with the same path parameter on multiple parameterized paths by using the path variable information from its neighbor.The effectiveness of the proposed schemes is verified by MATLAB simulation and physical experiment in this thesis.