FAM based controller as Kalman filter alternative applied to ship´s dynamic positioning control

This paper describes an adaptive computer-based dynamic positioning control system for floating vessels. The system is based on a mathematical model of vessel motion in response to external forces from thrusters, wind, water current and waves. The proposed system uses a control algorithm based on polynomial output feedback combined with feedforward compensation of external forces and internal coupling variables. Both subalgorithms, polynomial feedback and feedforward compensation are parameter updated by a gain scheduling method. The polynomial feedback locates dynamically for each wave disturbance characteristic (frequency and wave height), the closed-loop poles of the controlled system on the proper place, according a fuzzy rule-based adjustment procedure, following a reference model which constitute an alternative to the Kalman filter based in the poles shifting by a fuzzy associated memory (FAM) rule system, estimating the output feedback in such a way that avoids reaction of thrusters to high frequency motion of vessel. The graphic results are obtained by computer simulation using the simulation language Simnon