Analysis and Optimized Design of Manipulators/Mechanism for Minimally Invasive Robotic Surgery

Abstract

Robotic minimal invasive surgery has proven to increase the quality of sur gical operations and has also made possible new types of surgical procedures which were not previously achievable with conventional minimal invasive surgery. Various mechanical structures/mechanisms have been utilized as minimally invasive surgical manipulators. In particular, spherical mecha nism and the double parallelogram mechanism are the most widely used. In this thesis, we provide a kinematic analysis of the double parallelogram mech anism for its use as the external (arm) manipulator for minimally invasive robotic surgery. Two kinematic models of the said mechanism are developed with varying degrees of freedom. To have a quantitative analysis we provide certain indices of dexterity for the mechanism including mechanism singular ities, isotropy and manipulability. A comparative study of the spherical and double parallelogram mechanisms is performed. It is shown that the latter has certain advantages over its spherical counterpart. It was further noted that the link lengths do not af fect the kinematics of the double parallelogram mechanism. Evaluation of the kinematic properties like isotropy and manipulability ensures complete dex terity necessary for minimally invasive robotic surgery. Moreover, attempts have been made to propose, optimized manipulators designs using different performances indices and validated through simulations.