Optimal Nonsingular Terminal Sliding Mode Control of Cable-Driven Manipulators Using Super-Twisting Algorithm and Time-Delay Estimation

To ensure high-performance tracking control of cable-driven manipulators under complex uncertainties, we propose a novel optimal nonsingular terminal sliding mode (ONTSM) control scheme using super-twisting algorithm (STA) and time-delay estimation (TDE) technique. The TDE technique is applied as framework to take advantage of its model-free nature. Meanwhile, by introducing a quadratic performance index, we design an ONTSM manifold to achieve high dynamical performance in the sliding mode phase. Afterward, the modified STA is utilized to provide good performance in the reaching phase. Thanks to above three elements, the proposed ONTSM control with STA and TDE schemes is model-free and easy to apply in complicated practical applications. The stability of the closed-loop control system is analyzed considering the ONTSM and STA dynamics. Finally, comparative experiments were performed to demonstrate the effectiveness and superiorities of our newly proposed control scheme over two existing control schemes.