Continuum manipulators can conform to curvilinear paths and manipulate objects in complex environments,which makes it emerging to be applied in minimally invasive surgery(MIS).However,different and controllable operat...Continuum manipulators can conform to curvilinear paths and manipulate objects in complex environments,which makes it emerging to be applied in minimally invasive surgery(MIS).However,different and controllable operating stiffness of the continuum manipulator is required during different stages of surgery to achieve safe access or stable and precise operation.This work proposes an operating stiffness controller(OSC)for the typical tendon-driven continuum manipulator based on the variable impedance control method with Lagrangian dynamic modeling.This controller can adjust the operating stiffness by modifying the driving forces along the driving tendons of the continuum manipulator without changing its material or structure.The proposed OSC converts the damping and stiffness matrices of the impedance control into variable parameters.This merit allows it to dynamically adjust the operating stiffness of the continuum manipulator according to the desired constant or time-varying stiffness.Furthermore,the OSC stability can be proven based on a Lyapunov function,and its stiffness control performances have been analyzed and evaluated in both simulations and experiments.The OSC controller generated average relevant error values of 7.82%and 3.09%for the operating stiffness control experiments with constant and time-varying desired stiffness,respectively.These experimental results indicate that the OSC has high accuracy,stability,and strong robustness in the operating stiffness control tasks.展开更多
基金supported in part by Technology Program Project of Shaoxing City under grant 2023A14016the National Natural Science Foundation of China under grants 62211530111 and 92148201+1 种基金Science and Royal Society under IEC\NSFC\211360Graduate Research Innovation Project by Tianjin Education Commission under grant 2022BKY075.
文摘Continuum manipulators can conform to curvilinear paths and manipulate objects in complex environments,which makes it emerging to be applied in minimally invasive surgery(MIS).However,different and controllable operating stiffness of the continuum manipulator is required during different stages of surgery to achieve safe access or stable and precise operation.This work proposes an operating stiffness controller(OSC)for the typical tendon-driven continuum manipulator based on the variable impedance control method with Lagrangian dynamic modeling.This controller can adjust the operating stiffness by modifying the driving forces along the driving tendons of the continuum manipulator without changing its material or structure.The proposed OSC converts the damping and stiffness matrices of the impedance control into variable parameters.This merit allows it to dynamically adjust the operating stiffness of the continuum manipulator according to the desired constant or time-varying stiffness.Furthermore,the OSC stability can be proven based on a Lyapunov function,and its stiffness control performances have been analyzed and evaluated in both simulations and experiments.The OSC controller generated average relevant error values of 7.82%and 3.09%for the operating stiffness control experiments with constant and time-varying desired stiffness,respectively.These experimental results indicate that the OSC has high accuracy,stability,and strong robustness in the operating stiffness control tasks.
