An Improved Super-twisting Non-singular Fast Terminal Sliding Mode Control for 5-DOF Cable-driven Booms with Unknown Friction and Payload Mass

Purpose: 5-DOF cable-driven booms are widely utilized in large-scale construction, material handling, and related fields. However, inherent underactuated characteristics, unknown friction, and varying payloads hinder high-precision positioning and effective swing suppression. This study aims to address these challenges by developing a robust and collaborative control strategy. Methods: A nonlinear dynamic model is initially established to accurately characterize system behavior. An improved super-twisting non-singular fast terminal sliding mode control (ISNFTSMC) architecture is then proposed, integrating an adaptive mechanism. This scheme achieves collaborative control of position tracking and swing suppression through the construction of a coupled sliding manifold. Simultaneously, an enhanced reaching law is introduced to effectively attenuate sliding mode chattering. The stability of the closed-loop system is rigorously verified via Lyapunov criteria. Results: The proposed strategy is comprehensively validated through virtual prototype simulations and physical experiments. The findings demonstrate that, compared with conventional methods, the proposed ISNFTSMC algorithm increases positioning response speed by 11.1%–27.3% and enhances swing suppression performance by 44.8%–57.4%. Conclusion: The proposed control strategy successfully achieves precise payload mass estimation and superior disturbance robustness. It provides a highly effective and stable solution for overcoming the positioning and swing suppression limitations inherent in 5-DOF cable-driven booms.