Observer-based adaptive consensus control for nonlinear multi-agent systems with time-delay

In this paper, we consider the observer-based adaptive consensus tracking problem for a class of nonlinear time-delay multi-agent systems in the presence of input saturation. Under the assumption that the communication topology is directed and connected, a distributed adaptive consensus controller is developed based on the dynamic surface control technique. By constructing the nonlinear observer, the unmeasurable agents dynamics can be estimated. Input saturation problem is solved by a smooth function combined with an auxiliary variable. With the help of prescribed performance functions, the synchronization errors converge to the prescribed sets, which are characterized as a neighborhood of zero. According to Lyapunov stability theory, it is shown that with the proposed distributed consensus tracking approach, the consensus errors are cooperatively semi-globally uniformly ultimately bounded. Finally, a simulation example is provided to show the effectiveness of the proposed algorithm.