Comparison of remote center-of-motion generation algorithms

Abstract

Whenever a robotic assistant is designed for minimally invasive surgery (MIS), the trocar point constraint needs to be addressed. The robot assistant should generate a remote center of motion (RCM) that matches the trocar point position throughout surgery. There have been many studies regarding robot designs that handle this constraint on a mechanical level. Alternatively, software-based RCM generation algorithms, being more flexible, allow any robot geometry to be used. In this paper, the most well-known software-based RCM generation techniques that are applicable to any robot geometry are divided into two groups: world-frame-based techniques and trocar-frame-based techniques. Their advantages, disadvantages, and conditions for stability are discussed. All techniques are compared in a unified simulation of an endoscope control task. It is shown that when performing the same simulated trajectory, world-frame-based techniques may have algorithmic singularities, whereas trocar-frame-based techniques do not. Moreover, the need for closed-loop control of the RCM position is emphasized to avoid RCM drift.