A study on dynamics analysis of a small ship and pitch motion stabilization by engine speed control

This paper describes dynamics analysis of a small training ship and a possibility of ship pitching stabilization by adjusting engine speed. First, statistical analysis through multi-variate auto regressive(MAR) model is carried out. After upgrading the navigational system of an actual small training ship, in order to identify the model of the ship, the real data collected by sea trials on the ship were used. This analysis has shown that the pitching motion is influenced by the engine speed and it is suggested that there exists a possibility of reducing the pitching motion by controlling the engine throttle properly. Based on this observation, a new type of ship controller, which takes the pitching motion into account, is designed using the muti-variate modern control theory. Last, in order to evaluate the proposed controller, digital simulations by white noise are carried out. As results of simulations, the proposed system has good performance compared with the original data.