Second-Order Consensus of Networked Mechanical Systems With Communication Delays

In this paper, we consider the second-order consensus problem for networked mechanical systems subjected to nonuniform communication delays, and the mechanical systems are assumed to interact on a general directed topology. We propose an adaptive controller plus a distributed velocity observer to realize the objective of second-order consensus. It is shown that both the positions and velocities of the mechanical agents synchronize, and furthermore, the velocities of the mechanical agents converge to the scaled weighted average value of their initial ones. We further demonstrate that the proposed second-order consensus scheme can be used to solve the leader-follower synchronization problem with a constant-velocity leader and under constant communication delays. Simulation results are provided to illustrate the performance of the proposed adaptive controllers.Comment: 16 pages, 5 figures, submitted to IEEE Transactions on Automatic Contro

Robust Leaderless Consensus of Euler-Lagrange Systems with Interconnection Delays

In this work, a distributed control method to achieve the leaderless consensus of heterogeneous Euler-Lagrange (EL) systems with bounded time-varying communication delays while simultaneously rejecting periodic external disturbances is reported. The robust controller has a simple-to- implement structure of proportional-integral-derivative scheme that employs the internal model approach to reject the disturbance. We consider that the network of EL-systems is interconnected through an undirected weighted graph that is static and we assume that the information exchange between any connected nodes is subjected to bounded variable time-delays. The efficacy of the proposed method is shown in a numerical simulation using a network of ten robotic manipulators

Task space consensus in networks of heterogeneous and uncertain robotic systems with variable time-delays

This work deals with the leader-follower and the leaderless consensus problems in networks of multiple robot manipulators. The robots are non-identical, kinematically different (heterogeneous), and their physical parameters are uncertain. The main contribution of this work is a novel controller that solves the two consensus problems, in the task space, with the following features: it estimates the kinematic and the dynamic physical parameters; it is robust to interconnecting variable-time delays; it employs the singularity-free unit-quaternions to represent the orientation; and, using energy-like functions, the controller synthesis follows a constructive procedure. Simulations using a network with four heterogeneous manipulators illustrate the performance of the proposed controller.Peer ReviewedPostprint (author's final draft