A Hybrid Robust Time-Delay Control Framework With Integrated Disturbance Observer and Adaptive Sliding Mode Control for Robot Manipulators

This article proposes a hybrid robust time-delay control (HRTDC) framework that incorporates a disturbance observer (DOB) and adaptive sliding mode control (ASMC) within a time-delay control scheme. The DOB mitigates time-delay estimation (TDE) errors and effectively suppresses continuous low-frequency disturbances, while the ASMC rapidly compensates for abrupt high-frequency disturbances by adaptively tuning switching gains based on error dynamics. By leveraging the complementary strengths, the proposed HRTDC achieves robust compensation for both persistent and sudden nonlinear effects, including Coulomb friction, stiction, and discrete external disturbances. To the best of the authors’ knowledge, this work presents the first integrated HRTDC framework addressing both long-term and short-term TDE error compensation. The effectiveness and robustness of the proposed approach are validated through simulations and experiments conducted on robotic manipulators, demonstrating reduced overshoot, suppressed chattering, and significantly improved tracking accuracy compared to existing methods.