Cooperation and collision avoidance for multiple DP ships with disturbances

In this paper, we address the problem of cooperation and collision avoidance for multiple DP ships with disturbances. The DP ships are regarded as elliptical agents with nonlinear Lagrangian dynamics. We design control laws that guarantee cooperation as well as collision-free maneuvers. We show, using a two-step proof, that the avoidance part of the control laws guarantees safety of the agents independently of the coordinating part. Then, we establish an ultimate bound on the avoidance term. The obtained theoretical results are illustrated through numerical examples.