Adaptive Disturbance Rejection for Mixed Relative Degree Heterogeneous Multi-agent Systems With Switching Topology

A novel distributed adaptive disturbance rejection control scheme is developed for heterogeneous multi-agent systems with mixed relative degree under uncertain disturbance to achieve leader-follower output consensus under switching topology. First, a local output tracking error is introduced to transform the global leader-follower output consensus problem into a local output consensus problem between neighboring agents. Then, assuming known system parameters and disturbances, a distributed nominal high-order differential neighbor-sharing information based disturbance rejection controller is designed, based on the agent system control-disturbance relative degree matching condition. Based on this, a high-order sliding mode differentiator based precise estimation method is proposed to address the problem of difficulty in directly obtaining high-order differential neighbor-sharing signals in controllers due to mixed relative order differences. This method breaks through the traditional control design′s dependence on system relative order consistency and solves the problem of local-global output consistency in fixed/switching topologies. Furthermore, for the case where the system parameters and disturbances are uncertain, a distributed adaptive disturbance rejection controller is designed to achieve desired disturbance compensation and leader-follower output consensus under switching topology. The proposed control method can not only ensure closed-loop stability of the entire agent system and achieve leader-follower output consensus, without relying on global agent or leader information, but also achieve the expected disturbance rejection. Compared with conventional adaptive consensus control schemes, it also has the ability to handle the mixed relative order characteristics of heterogeneous multi-agent systems. Finally, the effectiveness of the proposed control scheme is verified through simulations.