Continuous Nonsingular Fast Terminal Sliding Mode Control of Cable-Driven Manipulators With Super-Twisting Algorithm

For the high-accuracy tracking control purpose of cable-driven manipulators under complex lumped uncertainties, a novel continuous nonsingular fast terminal sliding mode (CNFTSM) control scheme using a modified super-twisting algorithm (STA) is proposed and investigated in this paper. The proposed method applies the time-delay estimation (TDE) technique to estimate and compensate the unknown lumped system dynamics leading to an attractive model-free nature. Then, the NFTSM manifold and the modified STA scheme are used to ensure finite-time convergence performance in both the reaching and sliding mode phases. Thanks to the TDE technique, the proposed method is model-free and suitable to use in complicated practical applications; meanwhile, fast convergence, high tracking accuracy, and good robustness against lumped uncertainties can be ensured befitting from the CNFTSM control with NFTSM error dynamics and STA schemes. Stability of the closed-loop control system is proved. Finally, 2 degrees of freedom comparative simulations and experiments were performed to demonstrate the effectiveness and superiorities of our proposed method over the existing TDE-based robust control schemes.