Abstract: Ship dynamics is always hard to model, and the statistics of stochastic environment forces (wind, waves, current flow, etc.) are changing all the time in different sea states. Therefore, the authors introduce an adaptive fuzzy logic system in ship dynamic positioning. The dynamic model is obtained by learning the ship's drift dynamic behavior through using fuzzy logic. Furthermore, the desired control force determined by minimizing the error between predicted and desired ship position at the next step. Simulations at different sea states have shown that the scheme is effective.

Key words: fuzzy logic system, ocean engineering, dynamic positioning, adaptive modeling