I. Introduction
In the past decade, the cooperative control of multiple Lagrangian systems has attracted significant attention because the networked systems are of stronger robustness and higher efficiency than a single system. The distributed consensus problem is easy to implement and can be classified into leaderless and leader-follower cases. The latter one will be considered in this study due to its simplicity and scalability [1]. A critical problem is to design a leader-follower tracking controller to drive a team of followers to track a prescribed trajectory governed by a leader based on the local information exchange. As a consequence, lots of researches have been done on this topic [2], [3].