TIME-VARYING VECTOR FIELD GUIDANCE LAW FOR PATH FOLLOWING AND OBSTACLE AVOIDANCE FOR UNDERACTUATED AUTONOMOUS VEHICLES

This paper presents a time-varying vectorfield guidance law for path-following control of underactuated autonomous vehicles. The proposed guidance law employs a time-varying equation to calculate the desired heading angle. A sliding mode controller is designed to track the desired heading angle, and it is proved to be globally exponentially stable (GES). With this controller, the stability proof for guidance system is presented and the equilibrium point of the guidance system is Uniform Global Asymptotic Stable (UGAS). In order to avoid the obstacle when ship approaching the predefined path, a combined Path following and repelling field based obstacle avoidance system is proposed in this paper. Simulations are carried out to validate the performance of the combined path-following and collision avoidance system.