Codesign of dynamic collision avoidance and trajectory tracking for autonomous surface vessels with nonlinear model predictive control

Abstract

In this paper, a predictive control scheme for dynamic collision avoidance and formation trajectory tracking of autonomous surface vessels (ASVs) was designed. First, a trajectory-tracking nonlinear controller for ASVs was developed in the framework of model predictive control (MPC). Next, to realize leader-follower formation control, a graph topology approach was proposed to maintain a balanced distance between the leader and followers. Then, a set of nonlinear dynamic collision avoidance constraints based on the time to closest point of approach (TCPA) and distance to closest point of approach (DCPA) models was applied as control constraints. Specifically, the ship collision risk index (CRI) was proposed as a collision avoidance constraint for the controller. Simulation studies with various collision avoidance scenarios and predictive horizons were conducted using the dynamic CyberShip II model. The simulation results demonstrate the effectiveness of the proposed codesign scheme for formation tracking control and dynamic collision avoidance. Additionally, the simulation results show that the calculation time of the system was greatly reduced when using a trigger function, with an average calculation time of approximately 0.251 s.