Ship roll stabilization using an adaptive fractional-order sliding mode controller

Abstract

The current study designs an adaptive fractional-order sliding mode controller (AFOSMC) to diminish the undesirable effects caused by the ship roll motions. The ship roll dynamics combined with the fin actuator are employed for the controller design. The design steps are given as follows. At first, a non-integer sliding surface is utilized to design a fractional-order sliding mode controller (FOSMC). Then, an appropriate Lyapunov-based adaptation mechanism is designed to construct the adaptive version of the FOSMC. A Lyapunov candidate function is adopted to attain the ship roll stabilization through this adaptive control approach. The designed controller is robust to uncertain parameters in the ship roll dynamics and the fin actuator. Moreover, the effect of sea waves is reduced, as well. The robust performance of the AFOSMC is shown through numerical simulations.