Distributed event-triggered tracking control with a dynamic leader for multiple Euler-Lagrange systems under directed networks

The distributed tracking control for multiple Euler-Lagrange systems with a dynamic leader is investigated in this article via the event-triggered approach. Only a portion of followers have access to the leader, and the communication topology among all agents is directed that contains a directed spanning tree rooted at the leader. The case that the leader's generalized velocity is constant is first considered, and a distributed event-based control law is developed by using a velocity estimator. When the leader's generalized velocity is time-varying, novel distributed continuous estimators are proposed to avoid the undesirable chattering effect while guaranteeing that the estimate errors converge to zeros. With the designed distributed estimators, another distributed event-based control protocol is provided. Controller update frequency and resource consumption in our work can be reduced by applying the aforementioned two distributed control laws, and the tracking errors can converge to zeros. In addition, it is rigorously proved that no agent exhibits Zeno behavior. Finally, the effectiveness of the proposed distributed event-based control laws is elucidated by a number of simulation examples.