On the ship path-following control system design by using robust feedback linearization

The paper considers the problem of ship path-following system design based on input-output feedback linearization method combined with the robust control approach. At first, the nonlinear process model is linearized by means of partial coordinate transform and a simple system nonlinearity cancellation. Since the exact values of the model parameters are not known, the ensuing inaccuracies are taken as disturbances acting on the system. Thereby we obtain a linear system with an extra term representing the uncertainty which can be treated by using robust, H_∞ optimal control techniques. The performed simulations of ship path-following process confirmed a high performance of the proposed controller despite the assumed significant errors of its parameters.