Time-Delay Control of Cable-Driven Robots With Adaptive Fractional-Order Nonsingular Terminal Sliding Mode

To ensure high control performance of cable-driven robots under complicated lumped uncertainties, we propose a novel time-delay control (TDC) scheme with adaptive fractional-order nonsingular terminal sliding mode (AFONTSM) in this paper. The proposed control scheme utilizes time-delay estimation (TDE) to estimate and compensate the lumped unknown system dynamics and therefore ensures a fascinating model-free feature. A novel AFONTSM manifold is designed by considering the existing uncertainties using an adaptive algorithm. Then, the TDC scheme is designed using TDE technique and AFONTSM manifold and fast-TSM-type reaching law. Thanks to TDE technique, the proposed control scheme is model-free and can be easily applied in complex practical applications. Meanwhile, the high control accuracy and fast dynamical response can still be guaranteed benefitting from the AFONTSM dynamics and fast-TSM-type reaching law. Stability of the closed-loop control system is analyzed using Lyapunov method. Corresponding simulation and experimental results effectively demonstrate the validity and superiorities of our proposed TDC scheme with AFONTSM over the other three existing TDC schemes.