Output feedback adaptive robust control algorithm applied to ship steering autopilot with uncertain nonlinear system

A state feedback adaptive robust control algorithm is first presented for a ship steering autopilot with uncertain nonlinear system based on known parameter bound of the system and known bound of input disturbance by use of the theory of Lyapunov stability. Owing to not all states of ship motion being achieved and only ship course able to be measured on board, a high-gain observer is proposed to estimate the states of ship motion and then an output feedback adaptive robust control algorithm is developed. An example illustrating the method described is included for an ocean going training ship which belongs to our university. It is shown that the controller can make the designed system guarantee the satisfied performance by simulation based on the Matlab Simulink package.