Observer-Based Adaptive Fuzzy Control for Intelligent Ship Autopilot with State Constraint*

This paper studies the problem of autopilot heading control of intelligent ship with unknown yaw rate and state constraint. For the cases of adaptive fuzzy control, fuzzy logic system (FLS) is adopted to establish the unknown nonlinear function, a fuzzy state observer is constructed to obtain the unknown yaw rate, barrier Lyapunov function ensures that the tracking error is restricted. In the process of designing rudder controller, fuzzy state observer, state constraint are taken into account. Compared with traditional output feedback scheme, the observer-based state constraint control strategy can save more resource effectively. Based on Lyapunov stability theory, adaptive fuzzy approach is proposed to guarantee the desired control objective. Meanwhile, autopilot constrained requirement are also ensured. Finally, the simulation results are provided to illustrate the effectiveness of the proposed methods.