Development of a New Compliant Remote Center of Motion (RCM) Mechanism for Vitreoretinal Surgery

Minimally invasive surgery, especially vitreoretinal surgery, requires high precision micromanipulation for sensitive tissues. Robot-assisted surgery helps to reduce the imperfections of safety, stiffness, and ergonomics. Using Remote Center of Motion mechanism (RCM) in such surgeries ensures rigidity and stability for the manipulation and the safety for the patient. In this paper, a new planer compliant RCM mechanism is proposed. The performance of the proposed compliant mechanism is determined using finite element analysis by ANSYS software. Compliant mechanism with flexure joints achieves the required motion with acceptable rigidity and reduces the demerits of mechanical joints such as friction, backlash, and lubricant. Also, the pseudo-rigid-body method is utilized to model the compliant mechanism as a rigid body. Then, MS-ADAMS software is exploited for the dynamic modelling of the proposed mechanism. The co-simulation between MS-ADAMS and MATLAB is carried out to validate the motion of the mechanism using a PID controller. The results show improvements for the proposed design in terms of parasitic motions, RCM point drift and joint stiffening.