Study Of The Formation Control Protocol Design And Cooperative Transportation Of Multi-agent System

Object transportation is very common in the practical application.However,it is still difficult to transport objects in limited space or dangerous environment.Therefore,it is an urgent and challenging problem to implement the transportation through multi-agent system in the case of limited space environment,which can satisfy the demands of complex path planning and finally achieve the target position.In this thesis,the distributed formation control protocol design and cooperative transportation of multi-agent system are studied by combining linear temporal logic(LTL)theory and formation control theory.Distributed proportional control protocol,distributed PD control protocol and distributed PID control protocol are presented respectively for first-order,second-order and third-order multi-agent systems to ensure that the multi-agent systems can keep the desired formation.According to the requirements of the transportation task,the optimal path is planned by using the LTL theory.Thus the multi-agent systems transport objects while keeping the desired formation along the optimal path that derived through the method proposed.The distributed control method of similar formation is presented to solve the formation problem of the first-order multi-agent system.The designed controller can realize the formation of the multi-agent system.Firstly,the formation control problem of the multi-agent system is transformed into the stability problem.Secondly,the multi-agent system is decomposed into several subsystems and the stability of each subsystem is analyzed.Thirdly,the proportional controllers are designed to ensure the stability of the multi-agent system.The controller parameters which make the entire system stable can be obtained from the intersection of the stability range of each subsystem.The simulation is carried out to demonstrate the effectiveness of the designed controllers.Path planning algorithm based on LTL theory is utilized to search the optimal path to improve the efficiency of the transportation.Thus,the optimal path satisfying the requirement of task and environment is obtained.Finally,the simulation of cooperative transportation of the first-order multi-agent system satisfying the requirement of path planning is implemented by using the desired formation.Consensus protocols are designed for the formation control problem of the second-order and third-order multi-agent systems.The protocols design problems are transformed into the design problems of PD controller and PID controller.Then,the multi-agent system is decomposed into several subsystems.The stability of each subsystem is analyzed afterwards.The intersection of the stability ranges of the subsystems,which ensure the stability of the entire system,can be obtained according to the stability criterion of the complex constant coefficients linear system.In order to make the multi-agent system has high dynamic performance,the pole assignment problem of the second-order multi-agent system is studied.After that,the controller is used for studying the dynamic formation of the multi-agent system.And the dynamic formation algorithm meeting the speed requirements is derived.Finally,the cooperative transportation of the multi-agent system based on LTL theory in desired formation is achieved.The K-team robots are used to implement the formation control and the cooperative transportation experiments of multi-robot system on the experimental platform.The experiment results demonstrate that the control parameters obtained by the stability condition make the entire system stable,realize the desired formation and cooperatively transport objects along the derived path.The approach proposed in this thesis provides effective ways for transportation under limited space or dangerous environment.