Tracking control with external force self-sensing ability based on position/force estimators and non-linear hysteresis compensation for a backdrivable cable-pulley-driven surgical robotic manipulator

Cable-pulley-driven (CPD) manipulators are widely used in minimally-invasive surgical robots and systems. However, the cable-pulley systems also bring with significant nonlinear character-istics such as the hysteresis effect and elastic creep. Moreover, it is difficult to integrate the po-sition and force detection elements at the end of the surgical instrument. This study proposes a method of high-performance tracking control involving a self-sensing ability of external force based on the position/force estimators and non-linear hysteresis compensation (NLHC) algorithm for a CPD surgical robotic manipulator. The experiment results demonstrate that the proposed method can significantly reduce the tracking error of the joint angle and improve the position control accuracy to approximately 99% under a varying load. Additionally, the estimation res-olution of the self-sensing ability of external force was approximately 0.05 N. The method pro-posed in this study has potential applications in the motion control and force sensing of CPD manipulators, particularly for backdrivable CPD surgical robots.