Operational performance of an initial design of self-organising fuzzy logic autopilot

Given that the dynamic characteristics of small marine vessels are both non-linear and time variant, novel designs of autopilots must be able to cope with alterations in environmental conditions and/or operating conditions. Therefore, for a course-keeping autopilot to maintain the required near optimum level of performance it is a pre-requisite that a form of online learning capability is designed into the controller to enable the determination of any necessary internal adjustments. Considering a foundation autopilot design employing fuzzy logic, the formulation of a performance index is proposed to assess the level of vessel performance achieved, and to suggest suitable rulebase modifications as appropriate.