Distributed robust synchronization tracking control of networked Euler-Lagrange systems by cascaded estimation of reference velocity and position

This paper considers the problem of distributed synchronization tracking control of multiple Euler-Lagrange systems on a directed graph which contains a spanning tree with the leader node being the root. A virtual velocity single-integrator and a virtual position single-integrator are introduced in each agent, which are controlled by virtual distributed linear high-gain synchronization tracking controllers respectively, so that the virtual position and virtual velocity track those of the leader with arbitrarily short transient time and small tracking error. Then taking the virtual agent´s position and velocity as the estimates of those of the reference trajectory, in each generalized coordinate of each Euler-Lagrange agent, a local synchronization controller is designed. Simulation examples are provided to demonstrate the performance of the method.