Development of a Novel Tendon Sheath-Driven Upper Limb Exoskeleton with Elastic Joints for Assisting Surgeon Performing Microlaryngoscopic Surgery

When performing microlaryngoscope surgery, surgeons must maintain their arm positions for a long time, which can cause arm soreness and affect the success rate of surgery. In this study, a novel tendon-sheath-driven upper limb exoskeleton with elastic joints (TULEE) is proposed and developed to support the arms of doctors wearing the TULEE. The functional requirements of the TULEE were proposed according to the needs of microlaryngoscopic surgery, and the overall structure of the TULEE was designed. Then, the positive kinematics of the TULEE were derived based on the D-H transformation matrices, and the accuracy of the positive kinematic control was verified experimentally. The reachable workspace of the wrist joint of the TULEE was analyzed, and the dexterous workspace of the wrist was analyzed by using the condition number of the Jacobian matrix. The control strategy of the TULEE was proposed based on the principle of admittance control. Finally, an experimental prototype of the TULEE was built, and the feasibility of the control strategy was verified by a servo control experiment testing a single joint and a combined control experiment testing multiple joints. Through simulated surgical experiments, it was verified that TULEE can follow the wearer's arm movement, provide assistance for the wearer's arm movement in the following control mode, and lock the joint rotation angle in the steady-state control mode to reduce external disturbances and reduce the risk of unsuccessful surgery.