Robust Consensus of Multiple Euler–Lagrange Systems via a Distributed Reduced-Order Observer

This article first proposes a distributed reduced-order observer to estimate the complete state information of leader system. Particularly, the proposed observer only supposes those followers who can acquire partial output elements of leader, and whose communication network suffers communication link faults. Then, by applying the above distributed reduced-order observer, we further design a robust controller for multiple Euler–Lagrange systems (MELSs) to solve the leader–follower consensus problem (LFCP). Distinct with the existing controllers for LFCP of MELSs, this controller is robust for bounded external disturbances, and independent of the structure and features of the Euler–Lagrange system model. Finally, some simulation examples are given to show the effectiveness of the proposed distributed reduced-order observer and robust controller for LFCP of MELSs.