The design of ship autopilot via observer based adaptive feedback linearization

The paper considers the problem of ship autopilot design based on Bech´s model of the vessel. Since the model is highly nonlinear and some of the state vector coordinates are unavailable, the control system synthesis is performed by means of output feedback linearization method combined with a nonlinear observer. Due to considerable parameter variations typical here, an adaptive version of the method has been applied. The asymptotic stability of the overall system has been analyzed. The performed simulations of the ship course-changing process have confirmed a good performance of the proposed controller.