Adaptive stochastic sliding mode ship autopilot for way-point tracking

In This paper, way-point tracking control of a container ship based on LOS method using adaptive stochastic sliding mode control is investigated. Effective Control of ships in a designed trajectory is always an important task for ship maneuvering. The design is based on a low and high frequency model of the vessel motion adequate to ship steering. The low frequency model describes the vessel response to rudder control and slowly varying environmental forces. The high frequency model represents the wave induced oscillatory part of the yaw motion. For suppression of high frequency wave disturbances, the nonlinear recursive filter is considered. The uncertainty of model parameters in the presence of disturbances such as waves, wind and currents, dictate the application of techniques that take into account the nonlinear equations of ship´s motion and the presence of unknown parameters. In this sense, the adaptive stochastic sliding mode design is used for solving this problem. The simulation results show the suitability of this technique to compensate the time-varying disturbances effects in way-point tracking control.