Design and Evaluation of a Bending Actuator for a Robotic Uterine Manipulator, based on a McKibben Pneumatic Artificial Muscle

Abstract

A bending actuator for a robotic uterine manipulator was designed and evaluated. The actuator is based on a McKibben pneumatic artificial muscle (PAM) and aimed to reduce the surgeon’s operating time and lower the risk of patient injury. To enable the operation to be conducted using a laparoscope, the manipulator had to be able to manipulate the uterus in two degrees of freedom (2-DOF) with a minimum bending angle of ±45° and force of 3 N. Considering these requirements, three PAMs were placed using two disks at 120° intervals to manipulate the uterus in 2-DOF by pressurizing them. A kinematic model of the manipulator was derived and its workspace was computed. Based on this result, the manipulator was fabricated and its bending angle and tip force experimentally evaluated. We successfully demonstrated that the uterus could be controlled with a tip force of 3.31 N at a bending angle of 50°.