Analysis and Validation of a Teleoperated Surgical Parallel Continuum Manipulator

Abstract

In this letter, we present the design, kinematic analysis, model validation, and teleoperation of a miniature eight-degree-of-freedom (8-DOF) parallel continuum manipulator with a cable-driven grasper. Our motivation is to provide increased dexterity and stability in confined-space surgical applications, particularly for intraluminal endoscopic procedures. The system design uses six superelastic NiTi (Nitinol) tubes in a standard Stewart-Gough configuration and an integrated end effector that provides 180° articulation of two jaws actuated by Kevlar cables that pass through the tube legs. A computationally efficient inverse kinematics model provides real-time, low-level actuator commands to enable teleoperation. We provide a kinematic workspace analysis of this design, which depicts how mechanical strain, dexterity, and the effect of force application vary over the reachable workspace. We also experimentally characterize the open-loop model accuracy and repeatability of our physical prototype, obtaining mean errors of approximately 1.19 mm and 3.81° and a repeatability RMS error of 0.88 mm and 1.96°. Finally, we demonstrate the feasibility of minimally invasive surgical applications by conducting user trials for a pick-and-place task under unilateral model-based teleoperation.