Mechanical Design and Modeling of a Manipulator Tool for a Compact Multiple-Tool Single Port Laparoscopic Robot Platform

Abstract

Laparoendoscopic single-site surgery (LESS) has been shown to reduce the invasiveness of surgery by requiring only one incision to access the abdominal cavity. However, single-site surgery integrating with a compact robotic surgical platform remains as a unique challenge. To address this challenge, we have designed a comprehensive robotic surgery platform that consists of three 6-DOF manipulators and a laparoscope camera can all be inserted into the operation field through a single 18 mm cannula holding by one 4 degrees of freedom light-weight supporting frame. Each dexterous manipulator is 5+1 degree-of-freedom (DOF), serially inserted and removable, and remotely driven by 12 actuation tendons and is composed of rigid links joined by hybrid flexure hinges. This paper introduces the compact multiple-tool single port laparoscopic robot platform for the first time. Details of the mechanical design of the trocar and manipulator including joint design and tendon routing are presented. The forward and inverse kinematics of the manipulator are also discussed along with an analysis and simulation of the cooperative workspace of two manipulators. A preliminary dynamic model of the manipulator was also constructed to study the effect of tendon-sheath friction forces at various joint configurations. Future work will illustrate the existing supporting frame mechanism for posing tools and trocar.