Output Consensus Control For Nonlinear Multi-agent Systems Under States Constraints

In the distributed cooperation control of the multi-agent system,each agent can communicate with the neighboring agents,which improves efficiency and operation ability of the whole multi-agent system.Due to its wide range in practical applications and the advantages of low cost,high adaptability and easy maintenance,it has attracted the attention of many researchers.The existing literatures consider the multi-agent systems with first-order,second-order or high-order linear dynamics,but the actual physical systems are complicated with nonlinear characteristics,so it is of great significance to study the consensus problem of the high-order nonlinear multi-agent systems.With the development of research and practical needs,it is necessary to satisfy the performance constraints while achieving the stability of the system.Therefore,it is necessary to introduce a performance function to limit the states of the system.Based on the above analysis,this paper studies the output consensus control problem of the high-order nonlinear multi-agent system with states constraints and the main researches are the following two aspects:Firstly,for the high-order nonlinear multi-agent system with Prandtl-Ishlinskii hysteresis input and unknown external disturbance,the leader-following output consensus problem under the prescribed performance control is considered.In order to achieve a prescribed performance control of the output consensus error,the state transformation is used to convert the consensus error into a new error of the system.By designing the reduced order observer,the output feedback controller is designed based on the backstepping method and dynamic surface control technique.The influence of the nonlinear hysteresis input is eliminated by an adaptive method.According to Lyapunov stability theory,the closed-loop system satisfies bounded stability.The leader-following consensus can be achieved and the leader-following consensus errors can meet the prescribed performance requirements.Numerical simulation through MATLAB proves the effectiveness of the control algorithm.Secondly,for the nonlinear multi-agent system with disturbance,the leader-followingoutput consensus problem under full states constraints is considered.A reduced order dynamic gain observer is designed,and the Lipschitz condition on the nonlinear function is relaxed by using dynamic gain method.Distributed output feedback controller is designed by introducing an asymmetric tan barrier Lyapunov function(TBLF)to every step in backstepping.The bounded stability of the system is proved by Lyapunov stability theory,so the output consensus error and all the states in the closed-loop system can meet the performance requirements of the performance function in the TBLF.Numerical simulation through MATLAB proves the effectiveness of the control algorithm.