Output feedback adaptive control for autopilot design of an unmanned surface vehicle

This paper presents a study on autopilot design for an unmanned surface vehicle subject to dynamical uncertainty, time-varying ocean disturbances and unmeasured yaw rate. An output feedback adaptive steering law is developed based on a state observer and a neural network using iterative updating law. As a result, this approach is able to achieve automatic yaw control in presence of dynamical uncertainty and time-varying ocean disturbances without yaw rate measurement. Using a Lyapunov-Krasovskii functional, it is proven that the error signals are uniformly ultimately bounded. Simulation result is given to show the effectiveness of the proposed method.