AN APPLICATION OF FUZZY CONTROL AUTOPILOT TO FREE RUNNING MODEL EXPERIMENT IN STILL WATER AND DIRECTIONAL SPECTRUM WAVES

An autopilot system is necessary in order to perform a self- propulsion free running test. An autopilot based on PID control theory is generally used. However, there has recently been a tendency to apply fuzzy theory to process control in various industrial fields. In this report, fuzzy sets are applied to design the autopilot system to perform the free running model experiment in a towing tank with a radio controlled manoeuvring system. The experiment was carried out in the course-keeping and course-changing mode in both still water and directional spectrum waves with fuzzy and PD control. Here three scale factors are used, which have a relation to heading angle, turning rate and rudder angle respectively. A computer simulation using the M.M.G. model is compared with the experimental results, and a performance index is investigated to appraise the autopilot system and to determine the optimum scale factors.