A New Adaptive Time-Delay Control Scheme for Cable-Driven Manipulators

Abstract

This paper proposes a new adaptive time-delay control (ATDC) scheme for cable-driven manipulators. The proposed ATDC scheme contains three elements, i.e., time-delay estimation (TDE), injected dynamics, and adaptive laws. The TDE utilizes intentionally time-delayed signals to estimate the unknown system dynamics and brings a fascinating model-free nature. The injected dynamics employ a fractional-order nonsingular terminal sliding mode (FONTSM) manifold and a fast-TSM-type reaching law, thus it can ensure fast dynamical response and high tracking accuracy in both sliding mode and reaching phases. The adaptive laws are utilized to obtain good robustness and effective suppression of the chatters simultaneously. Moreover, the continuous and chatter-free adaptive gains are used to enhance the control performance under time-varying disturbances. The tracking error is proved to be uniformly ultimately bounded (UUB) using Lyapunov approach. Finally, the superiorities of the proposed ATDC scheme are demonstrated by three experiments using a cable-driven manipulator.