Output Consensus Controller Design for Nonlinear Relative Degree One Multi-Agent Systems with Delays*

Simple design conditions are presented for decentralized output feedback controllers that achieve output consensus between nonlinear, relative degree one Multi-Agent Systems (MAS) with stable zero dynamics. It is shown that consensus is achieved even if the exchange of information between the agents suffers from time-varying communication delays and switching communication topologies. In this way the assumptions both on the network topology and the delays are minimal. The proofs are based on an invariance principle for Lyapunov-Razumikhin functions, which has been recently used to prove consensus between single integrator MAS.