Design and optimization of a compliant parallel robotic surgical instrument with multifunctional forceps for minimally invasive surgery

Abstract

Minimally Invasive Surgery (MIS) technique has seen its great success in the last few decades due to its significant advantages compared to the traditional open surgeries. This technique requires only a few 10 mm incisions through which the surgical instruments can be inserted to perform operations inside the human body. The benefits it brings to surgeons and patients are so obvious that recent advances in MIS continue to demand the development of surgical tools for different types of MIS. This thesis presents a surgical instrument based on compliant parallel mechanism with multifunctional forceps attempting to overcome the problems arise from the advances in MIS. Due to the inherent properties of compliant mechanism, the surgical tool can be designed very compact to meet the strict requirements of MIS with very restricted operation area. With parallel mechanism, this tool has multiple degrees of freedom and the stiffness to transmit motions dexterously and accurately. By integrating the PCB motor, the end-effector is able to rotate 360 degrees. The parallel mechanism was analyzed in terms of kinematics, workspace and stiffness modeling. Workspace and stiffness were optimized using Genetic Algorithm to get the optimal performance out of this parallel mechanism. The multifunctional forceps with the functions of scissor-cutting, grasping and Cautery was also designed. The CAD model was constructed and Finite Element Analysis was conducted to make sure that the design meets the requirements.