| Multi-robot formation improves the efficiency of robots in completing complex and dangerous tasks.In recent years,the coordinated control of multi-autonomous mobile vehicles has attracted great attention.Because this system has many potential advantages on a single robot,including greater flexibility,adaptability and robustness to unknown environments.In this field,formation control has always been the concern of many researchers.Formation control is a control method that a group of robots form a specific geometry(such as wedge or chain)and keep the formation.The potential applications of formation control include detection,surveillance,search and rescue,carrying large objects and controlling satellite arrays.The contents of this thesis are as follows:(1)Three small wheeled mobile robots based on embedded system have been designed and manufactured by myself,which serve as the experimental platform for later research on formation control of robots.The small robot system consists of four modules:(a)Velocity measurement module:including the acquisition of the robot’s own motion speed and the calculation of the robot’s position and posture.(b)Information transfer module:the leader position information is transmitted to the follower robot through this module.(c)Motor control module:double closed-loop PID control is used to improve the accuracy of motor control.(d)Formation control module:the formation control algorithm is mainly realized by wheeled mobile robots.(2)In this section,robot formation control in multi robot cooperative system is studied.A pilot-follower formation control algorithm with speed and acceleration constraints is designed.Two first-order filters are designed as two feedback signals of the controller,and the size of the feedback signal and its derivatives are limited by two filter parameters.The Lyapunov theory proves that the closed-loop system is asymptotically stable and the speed and acceleration of the robot are bounded.Finally,simulations and experiments verify the effectiveness of the proposed algorithm.(3)In this section,a fast terminal sliding mode controller is presented for the kinematic model of a wheeled mobile robot with nonholonomic motion.Firstly,feedback linearization is applied to the formation control model of wheeled mobile robots,and then a tracking controller is designed for the feedback linearization model,so that the follower robot can converge to the desired position of the pilot robot.Finally,simulations and experiments verify the effectiveness of the proposed algorithm. |
