Enhancement of High-Fidelity Haptic Feedback Through Multimodal Adaptive Robust Control for Teleoperated Systems

Achieving high-fidelity haptic feedback in teleoperated robotic systems is crucial, particularly in applications, such as medical, industrial, military, space, and underwater explorations. The quality of haptic feedback depends to a great extent on the controller design objectives, such as stability and transparency. In addition to the time delay, the most challenging issues that affect haptic feedback are model uncertainties, parametric variations, and external disturbances. In this article, such issues have been addressed by developing a novel multimodal adaptive robust control algorithm for teleoperated systems with time-varying delay. Here, parametric convergence is achieved swiftly with a milder condition than a stronger persistent excitation condition on the regressor signal, resulting in the enhancement of transient performance. The proposed method ensures the robustness of the system against bounded perturbations and high-frequency unmodeled dynamics using a modified terminal sliding-mode controller alongside the adaptive scheme. The proposed method promises high-fidelity haptic feedback to the operator by ensuring improved robust global asymptotic stability, synchronization, and transparency, addressing parametric variations and disturbances. The validity of the proposed adaptive robust control law is substantiated through simulations and comparisons with the existing methods for a 2-R teleoperation system. The experimental results for a 1-R teleoperation system are also presented.