Development of Visible Manipulator With Multi-Gear Array Mechanism for Laparoscopic Surgery

In recent years, robotic technology has been introduced to medical fields, and many surgical robots have been proposed for minimally invasive surgery (MIS). However, due to the limitations in dexterity imposed by surgical instruments and occlusion area, surgeons experience great difficulties during operations. In this paper, we propose a visible manipulator for laparoscopic surgery. Unlike other multiple degree-of-freedom (DOF) manipulators that utilize compliant parts or tendons and pulleys, our proposed manipulator adopts a multi-gear array mechanism to perform the yaw and pitch motions. The manipulator is integrated with a visualization unit to provide macroscopic images for observation in a constrained cavity. Moreover, flexible surgical tools with different functions can be inserted through the central channel of the manipulator to perform diagnostic or therapeutic procedures. A master-slave system is developed to control the bending motions. Bending characteristics experiments and load capacity experiments are performed. The experimental results demonstrate that the proposed manipulator can perform bending motions with a yaw angle range of -76.8°~76.2° and a pitch angle range of -75.2°~75.6°. The manipulator can lift a workload of 250 g during yaw motion and a workload of 150 g during pitch motion, demonstrating the potential clinical value of the visible manipulator for robot-assisted surgery.