Consideration of performance assessment criteria required for a self-organising fuzzy logic autopilot

Small vessels are highly non-linear time variant systems. Autopilot control of such vessels requires on-line learning features to ensure optimal performance levels as variations in both environmental conditions and vessel dynamic characteristics occur. A performance assessment criteria is therefore proposed which utilises both heading error and rate of change of heading error as a means of assessing vessel performance and rudder activity in the small vessel application. Results from full scale sea trials are discussed to validate the proposed design.