Adaptive recursive sliding mode based trajectory tracking control for cable-driven continuum robots.

To improve the transient response, accuracy and robustness of trajectory tracking control for cable-driven continuum robots (CDCRs), a recursive integral terminal sliding mode control combined with an adaptive disturbance observer (ADO-RITSMC) is proposed. The recursive integral terminal sliding mode control (RITSMC) guarantees fast transient response and high tracking accuracy with a fast zero convergence of the tracking error without chattering. To attenuate the effect of uncertain dynamics, an adaptive disturbance observer (ADO) is constructed to derive uncertain dynamics. Particularly, an improved grey wolf optimizer (IGWO) is merged into the ADO to enhance the estimating accuracy of uncertain dynamic factors. Simulation and experiment results demonstrate the superiority of the ADO-RITSMC in enabling fast transient response, high accuracy and strong robustness of trajectory tracking control. • The RITSMC achieves a fast zero convergence and high-precision trajectory tracking control without chattering. • Assigning a starting value for the integral term of the RISMC function to improve the transient response of the controller. • An ADO is designed to estimate uncertain dynamic factors and compensate for the control input. • An improved grey wolf optimizer (IGWO) is introduced into ADO for more accurate estimation of uncertain dynamic factors. [ABSTRACT FROM AUTHOR]