Workspace analysis of robotic manipulators for a teleoperated suturing task

An important missing piece in the medical robotics literature is the lack of systematic methods to quantitatively compare different manipulator designs, and to evaluate kinematic configurations chosen for telesurgical manipulators in application-critical tasks. Such a quantitative method is especially important during design stage to make an informed decision between various design alternatives. In this paper, a quantitative method to evaluate the kinematic ability of surgical manipulators to perform the critical tasks of suturing and knot tying is presented. The proposed method does not require a physical prototype. This is achieved by running typical tool motions during these tasks through the inverse kinematics of the manipulators and checking if the system can accommodate the desired motions. The system can perform a given motion if the whole trajectory lies continuously within the workspace of the manipulator. Open surgical suturing motion data collected from experiments done with expert surgeons is used as the set of desired tool motions used in the analysis. The method is applied to compare two different wrist configurations of telesurgical slave manipulators, intended for use in minimally invasive surgery, by looking at the requirements on joint ranges and wrist manipulability during these motions.