Fin stabilizer control strategy based on adaptive sliding mode

• Systematic Dynamics Analysis: This research provides an in-depth analysis of the ship's rolling dynamics under irregular wave conditions, laying a theoretical foundation for subsequent control strategies. • Mathematical Model Establishment: Successfully developed a mathematical model for ships under nonlinear wave disturbances, providing a scientific basis for precise control. • FNAFTSMC Control Strategy: Innovatively introduced the Fractional-order Nonsingular Adaptive Fast Terminal Sliding Mode Control strategy to effectively manage fin stabilizers and reduce rolling motion. This control strategy takes into full consideration the impact of uncertain system parameters and unknown disturbances, and has strong robustness. • Significant Performance Enhancement: By incorporating fractional-order derivatives and terminal sliding mode, anti-rolling performance is significantly improved, and the chattering effect is effectively reduced. Compared to the classical PID control method and other Sliding Mode Control methods, the designed controller achieves over 90 % reduction in rolling motion across various sea states. • Broad Application Prospects: The control approach proposed in this study is not only suitable for ship rolling control but also extendable to path tracking and attitude control applications. Ships are typically equipped with fin stabilizers to effectively weaken ship’s roll and enhance the voyage's safety. To achieve better anti-roll performance, this study proposes an adaptive sliding mode control (SMC) method for a roll reduction controller. We combine fractional calculus with terminal sliding mode control and consider the sliding surface s 1 as the control target, forming a novel second-order terminal system. At first, we establish a mathematical model of irregular ocean waves and constructed a roll motion model for a ship subjected to nonlinear wave disturbances. Subsequently, we propose a novel control strategy named Fractional-order Nonsingular Adaptive Fast Terminal Sliding Mode Control (FNAFTSMC). By incorporating fractional-order derivatives, high-order terminal sliding mode and uncertainties, the proposed method significantly improves anti-roll performance, and effectively reduces the chattering effect. The superiority of the strategy is demonstrated through simulation experiments compared with the classical PID controller method and other three types of Sliding Mode Control (SMC) methods. Results indicate that the proposed controller achieves over a 90 % reduction in rolling motion across various sea states and exhibits superior anti-rolling retention capabilities.