Design of discrete fuzzy controller for norrbin ship steering

A discrete T-S fuzzy model of ship steering is established. Based on the properties of fuzzy systems with two-overlapped fuzzy partition (TFP) inputs, a new sufficient condition to check the stability of closed-loop fuzzy control systems is proposed via piecewise discrete Lyapunov function constructed in maximal overlapped-rule group. This condition only requires finding a common positive-definite matrix in each maximal overlapped-rule group. Compared with former stability analysis approaches, it can not only overcome the defect of finding a common positive-definite matrix but also reduce the number of solving Lyapunov inequalities. In addition, by using the method of parallel distributed compensation (PDC), a controller of discrete T-S fuzzy control systems for ship steering is designed. Simulation example shows the method is effective and advantageous.