Design of the robust PID course-keeping control system for ships

Abstract

The paper presents the design of PID ship course-keeping autopilot of high steering performance and which is robust against ship dynamic motion variations. The basis for the design was a simple linear model of ship dynamic motion, but model's variations due to velocity were also considered. The PID controller coefficients were selected by using the performance indices: the settling time and ITAE integral performance index. The designed PID controller was tested by means of computer simulations. For that aim a nonlinear, directionally unstable ship model was used.