Design of ship motion controller based on discrete fuzzy multi-model approach
The problems of the discrete fuzzy controller design for the ship motion system and the stability analysis for the closed-loop discrete fuzzy system are studied. Firstly, a discrete T-S fuzzy model of the ship motion system is established; then, by using the method of parallel distributed compensation, a new sufficient condition to check the stability of the closed-loop discrete T-S fuzzy system is proposed based on the definition of the discrete piecewise fuzzy Lyapunov function. This condition only needs satisfying the condition of the fuzzy Lyapunov approach in each maximal overlapped-rule group. Therefore, the proposed condition is less conservative and difficult than the common Lyapunov approach and the fuzzy Lyapunov approach. Finally, a fuzzy controller of a ship motion system is designed, and the simulation results show that the approach proposed is effective.