Consensus and disturbance attenuation in multi-agent chains with nonlinear control and time delays

In this paper, we investigate consensus and disturbance attenuation in a chain of mobile agents, which include non-autonomous agents, semi-autonomous agents and autonomous agents. In particular, the nonlinear dynamics of non-autonomous agents is given and cannot be designed, while the dynamics of semi-autonomous and autonomous agents can be partially and fully designed, respectively. To improve the robustness of multi-agent chains against disturbances, we propose a nonlinear control framework for semi-autonomous and autonomous agents such that they mimic the behavior of non-autonomous agents for compatibility while also exploiting long-range connections with distant agents. This framework ensures the existence of a unique consensus equilibrium, which is independent of the network size, connectivity topologies, control gains and information delays. Robustness of multi-agent chains against disturbances is investigated by evaluating the frequency response at the nonlinear level. For infinitely long multi-agent chains with recurrent patterns, we also derive a condition that ensures the disturbance attenuation but only requires the analysis of the linearized model. A case study is conducted for a connected vehicle system where numerical simulations are used to validate the analytical results. Copyright © 2016 John Wiley & Sons, Ltd.