Observer-based consensus design for multi-agent systems with unavailable velocities of leader and followers

This paper addresses the observer-based consensus problem of second-order leader-follower multi-agent systems with switching topology where none of velocities of leader and followers can be available. Firstly, under the assumption that the acceleration of the leader is active and known to all followers, instead of estimating directly the unmeasured velocities as done in the existing work, this work estimates the dynamic differences of the velocities between the leader and the followers by designing distributed observers. A common Lyapunov function is used to analyze the closed-loop stability. Secondly, the idea is further extended to two cases where the acceleration of the leader is constant but unknown to all followers or active but known only to some followers. A simulation example is provided to verify the effectiveness of design methods proposed in this paper.