Research On Multi-robot Formation Control And Transformation Strategy

With the continuous development of communication,sensing,group control technology and robotics technology,multi-robot collaborative control has become a current research focus.After years of development,multi-robot collaboration has been widely used in military,industry,national defense,life,production and other fields.For some specific task scenes,such as multi-robot cooperative transportation,map exploration,target grasping,large stage performance,etc.,multi robot system is required to form the required formation structure,and to keep stable formation or change the formation during the process of completing complex tasks.This thesis took the incomplete wheeled mobile robot as the research object,took the cooperative performance as the application background,and made an intensive study on multi-robot formation keeping,multi-robot formation transform and multi-robot formation obstacle avoidance.The specific contents are as follows.Firstly,the formation keeping problem of multi robot system is analyzed.This thesis analyzes the dynamics and kinematics of the wheeled robot.On this basis,the leader-virtual follower model and virtual structure model of the system are established,and the error equations of the multi-robot system are obtained.Moreover,based on Lyapunov Stability Theorem and Backstepping Method,a multi-robot cooperative formation keeping algorithm is designed.Compared with general control laws,the effectiveness and advantages of control laws are verified through a simulation.Secondly,the formation transform of multi-robot is studied.Based on the objective function of minimum completion time and minimum energy consumption,a Discrete Particle Swarm Optimization Algorithm with linear decreasing inertia weight is proposed.The idea of velocity difference is applied to the scheme of multi robot formation transform.The operator in the algorithm is redefined based on the formation transform problem.Finally,the matching scheme of optimal formation transform without collision is given.Thirdly,based on the Consistency Theory,the formation transform of multi-robot system and the obstacle avoidance problem in the transformation process are discussed.Taking the desired formation as the task target of multi robot formation,the control of the target point is added into the control law.Design smooth bump function,use ?-norm replaces the general Euclidean norm,and constructs a smoothly collective potential function and spatial adjacency matrix to ensure the smoothness and stability of the formation.And considering the obstacles in the formation transform process of multi-robot system,the topology of flocks is redesigned,and the repulsive effect of obstacles is added into the control law.An improved consistent formation algorithm with obstacle avoidance ability is designed,which can avoid the interference of static and dynamic obstacles.Finally,based on the research results in the previous chapter,the thesis considers how to realize formation keeping and formation transformation in the multi robot system in the actual application scene.The overall formation control strategy of multi robot to realize formation maintenance and formation transformation is designed.In order to solve the problem of formation transformation,a hybrid formation transformation strategy based on particle swarm optimization and consistency algorithm is proposed,which improves the efficiency of the whole solution.