Design and Optimization for a Cardiac Active Stabilizer Based on Planar Parallel Compliant Mechanisms

Abstract

Giving assistance to surgeons during beating heart procedures is currently a great challenge in medical robotics: a high level of safety is required while the beating heart yields high forces and dynamics. In this article, we investigate the design of an active cardiac stabilizer that will provide a motionless area of interest during the surgery. A device architecture is introduced that is based on planar parallel mechanisms. Such mechanisms are particularly interesting for their manufacturing simplicity and compactness. With the considered architecture, spherical compliant joints based on a planar structure need to be designed. Here we present the use of a 3-RRR spherical parallel mechanism. Its kinematic and stiffness analysis are performed using pseudo-rigid body modeling. An optimization of the mechanism is then achieved, using a modified ant colony optimization technique. The achievable performance of this type of compliant spherical joint is then discussed before concluding on the device adequacy with respect to the surgical requirements.