Fast Terminal Sliding Mode Control for the Ship Steering Problem

In this paper we propose the application of a robust terminal sliding mode control with fast sliding surface to the ship control problem, which consists of leading the ship along the desired course via automatic changes in the rudder blade deflections. In spite of its robustness to system parameter variations and external disturbances, normal terminal sliding mode control (NTSMC) has a limitation of shattering the input rudder angle command particularly when the ship steering mechanism has a big time constant. Through comparative simulations, we show that the proposed controller with fast sliding surface outperforms NTSMC controller in reducing the chattering in the input signal and the initial swing of the rudder angle in the presence of external disturbances and model uncertainties.