A fixed-time prescribed performance sliding mode control of ship sail three-degree-of-freedom control system under input saturation
SONG Jian
ZHANG Lan-yong
LIU Sheng
Abstract：To address the challenges posed by external wind disturbances,input saturation,angle constraints,and the need for smooth and rapid tracking,this paper proposes a fixed-time prescribed performance sliding mode control strat-egy(FTSMC-PP-IS)for the three-degree-of-freedom control system of ship sail.Firstly,a fixed-time convergent sliding mode surface is developed using the bi-limit homogeneous property(BHP)to ensure rapid fixed-time convergence while avoiding singularities in the control law.Next,a prescribed performance function(PPF)is designed to meet the system's three-degree-of-freedom angle constraints and to optimize tracking overshoot and steady error.Additionally,a fixed-time auxiliary system is introduced to compensate for actuator input saturation deviations.The global fixed-time convergence of the system is assured by constructing the sliding mode reaching law and the equivalent control law.Notably,this approach achieves excellent dynamic and steady-state performance while ensuring rapid fixed-time tracking under input saturation conditions.Finally,the fixed-time convergence of the proposed method is validated through Lyapunov stability theory.Numerical simulations and prototype experiments confirm the feasibility and effectiveness of the proposed method.
Keywords：ship sail three-degree-of-freedom control systemfixed-time sliding mode controlmotion controlinput saturationprescribed performanceangle constraintbi-limit homogeneous property
Publication Date：2025-10-30
Online Publishing Date：2025-11-13(First online date of this platform, not the publication date of the document)
Pages：10( 1936-1945 )