This paper proposes a new adaptive time- delay control (ATDC) scheme for cable-driven manipulat- ors. 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 dyna- mics 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 performan- ce under time-varying disturbances. The tracking error is proved to be uniformly ultimately bounded (UUB) using Lyapunov approach. Finally, the superiorities of the propo- sed ATDC scheme are demonstrated by three experiments using a cable-driven manipulator.

A new adaptive time delay estimation technique with sliding mode control method is proposed and investigated in this passage for cable-driven manipulators. Time delay estimation technique is an effective tool to compensate for unmodeled dynamics and unknown disturbance, and adaptive time delay estimation performs better due to its adaptive control gain. The proposed adaptive method is based on the fuzzy logic algorithm which has a great advantage in input–output mapping thank to its flexibility. Tuning procedure is addressed to reveal the implementation of the newly proposed algorithm. Moreover, the desired trajectory is taken as an input of adaptive algorithm and better control performance is obtained through this attempt. The proposed controller is ultimately uniformly bounded and proof using the Lyapunov method is provided. Finally, comparative experiments show the validity and effectiveness of the proposed controller.

This paper proposes a new adaptive fractional-order nonsingular terminal sliding mode control scheme integrated with time delay estimation (AFONTSMC–TDE) for cable-driven manipulators. The proposed AFONTSMC–TDE scheme consists of three key elements: time-delay estimation (TDE), a fractional-order nonsingular terminal sliding mode (FONTSM) manifold, and an adaptive variable-gain reaching law. The TDE utilizes intentionally delayed signals to estimate unknown system dynamics, thereby providing a model-free control framework. The FONTSM manifold ensures fast finite-time convergence while inherently avoiding singularity, and the adaptive reaching law dynamically adjusts control gains to achieve rapid response and effective chattering suppression simultaneously. The tracking error is proved to be uniformly ultimately bounded (UUB) via Lyapunov stability analysis. Finally, the superiorities of the proposed AFONTSMC–TDE scheme are validated through experiments on a cable-driven manipulator, demonstrating significant improvements in tracking accuracy over existing fractional-order sliding mode control methods.

Tendon-driven manipulators possess obvious advantages compared to rigid-link manipulators, such as lighter weight, greater flexibility, and adaptability to confined spaces. To solve the problems of backlash and improve the accuracy of motion in specific application environments, this paper proposes a novel single-tendon-driven design for each joint of the manipulator. Kinematic modeling of the manipulator is systematically derived. Then, a decoupling algorithm is designed to mitigate motion coupling effects and enable accurate mapping between motor inputs and joint motions. Moreover, to improve the accuracy of trajectory tracking control for the tendon-driven manipulator, this paper proposes a nonsingular terminal sliding mode (NTSM) control scheme based on time-delay estimation (TDE). TDE is used to estimate unknown disturbances. An adjustable parameter was introduced based on TDE technology, which can enhance the system’s robustness against uncertainties and external disturbances. The stability of the closed-loop control system is verified through Lyapunov stability theory. Finally, decoupling experiments are conducted to validate the kinematic model and the feasibility of the proposed design. And comparative experiments are performed to prove the advantages of the proposed control scheme.