Backstepping adaptive tracking fuzzy control for ship course based on compensated tracking errors

Ship motion is featured by nonlinearity, uncertainty and etc. This study addresses a adaptive fuzzy controller design for ship steering in the framework of uncertain strict-feedback nonlinear system. Lyapunov candidate function is formulated based on compensated tracking errors. Therefore, iterative differential manipulations are circumvented in conventional ship course adaptive backstepping controller. Takagi-Sugeno (T-S) fuzzy system is utilized to approximate ship motion's uncertain nonlinear part. And the proposed controller needs no a priori knowledge about ship's system dynamics. Only two adaptive laws learn the system's unknown parameters online. The design can guarantee the ultimate uniform boundedness of the signals in closed-loop system. Simulation researches take ship Yulong as an example. Its aim is to make ship course track the reference model's output. The results demonstrate the controller's effectiveness.