Path Following Control for Underactuated Marine Robots Based on Direct Dynamic Programming of Desired Yaw Angle

For the problem of straight-line cruise, a control method for the path following of marine robots based on direct dynamic programming of the desired yaw angle is proposed in this paper for underactuated marine robots. Different from the typical path following control method, i.e., the line of sight algorithm (LOS), the desired yaw angle of marine robots is dynamically programmed directly according to the lateral error on the desired path in the Serret-Frenet (SF) frame, Hence, the lateral error of the robot is guaranteed to converge to zero. Meanwhile, the longitudinal error of the robot is reduced by timely adjusting the virtual velocity on the tangent line of the desired path point. Furthermore, the control law is obtained based on the programmed desired yaw angle and prescribed longitudinal velocity, together with RBF neural network estimation. Finally, the control scheme proposed in this paper is used on a marine robot for simulation verification by comparing with an extent improved LOS path following control method. The simulation results demonstrate that the longitudinal and lateral following accuracy and the smoothness of the control signals have better performance when applying the proposed control scheme.