Design and optimization of a 2-degree-of-freedom planar remote center of motion mechanism for surgical manipulators with smaller footprint

This paper presents a new remote center of motion (RCM) mechanism design for Minimally Invasive Surgery (MIS) robotic manipulators, capable of providing two important degrees of freedom (DoFs) — pitch and translation — purely through its mechanism design. Novelty of the proposed design is that it offers a significantly smaller footprint compared to the existing state-of-the-art 2-DoF planar RCM mechanisms. We describe the design, perform kinematic analysis, and use simulation to validate its RCM capability. The design is also optimized using manipulability and tool translation to achieve maximum kinematic performance with smallest size of the proposed mechanism. A comparison between the mechanism workspace and the required workspace shows that the proposed design meets the MIS workspace requirements. Optimization results demonstrate that the proposed design offers same kinematic performance as of an exiting design, but with a significantly smaller footprint. Compact distal-end and smaller footprint make the proposed design ideal for applications requiring multiple manipulators to operate in close proximity.