A HYDRODYNAMIC MODEL FOR SIMULATING SWATH SHIP MOTIONS WITH FUZZY CONTROL

Article type: Research Article

Authors: Fang, Ming-Chung | Chiou, Shan-Chin

Affiliations: Department of Naval Architecture and Marine Engineering, National Cheng Kung University, Tainan, Taiwan

Abstract: A time simulation technique with fuzzy control algorithm is evaluated to predict the motion response of the SWATH ship with controllable stabilizer fins in longitudinal regular and irregular waves. In the paper, a mathematical model including the effect of surge force, viscous force, and the fin force is developed to simulate the SWATH ship motion. The stabilizer fin control using the fuzzy algorithm is applied to reduce the pitch motion of the SWATH ship. Basically the fuzzy controller consists of five parts: (1) Fuzzifier (2) Rule base (3) Data base (4) Inference engine (5) Defuzzifier. The calculations of the corresponding hydrodynamic coefficients at each time step follow the simplified technique developed before, which needs only one set of initial input data of the ship configuration. After comparing with the previous technique, i.e. "bang-bang" control, we find that the present fuzzy control appears to be more practical for operating stabilizer fins. Therefore, incorporating the fuzzy control algorithm, the hydrodynamic model developed here may offer more valuable contributions to the SWATH ship design with controllable fin effects.

Journal: International Shipbuilding Progress, vol. 48, no. 4, pp. 277-303, 2001