Core technology

Remote Center of Motion

The definition of Remote Center of Motion (RCM) is the center of rotation fixed at a point (patient’s incision) where no mechanical component exists. There are several advantages: 
1. RCM is always above the patient that minimizes the risk of collision between the robot and patient’s body; while in the same time provide sufficient range of motion to operate the instruments. 
2. The control of RCM is decoupled in X, Y and Z-axis and provides simple forward and inverse kinematics to know the position to control robot. 

Different mechanisms to provide RCM

The state of the art MIS Robot uses the RCM derived from parallelogram RCM mechanism. It provides big range of motion and sufficient payload. Another circular-prismatic-joint RCM mechanism exists on the commercial camera holder robots but the application is restricted by its small range of motion and little payload. Different from them, the Adjustable-RCM is derived from the instantaneous RCM mechanism to achieve comparable range of motion, big payload, small device foot print, and small working profile for a MIS Robot. The unique point of ARCM is the embedded function of adjusting the center of rotation to align with the incision of the patient. The ARCM technology is applied on the VESALIUS Robot platform and is currently patent pending (PCT/EP2010/056611) 

RCM type

Robot

Surgical application

Range of motion

Device footprint

Stiffness

Payload

Working envelope

Parallelogram RCM mechanism

daVinci by Intuitive Surgical

MIS

Big

Big

High

High

Big

Instantaneous RCM mechanisms

VESALIUS Robot by Tang

Laser surgery*

Camera holder*

Big

Small

High

High

Small

Circular-prismatic-joint RCM mechanism

ViKY by EndoControl

Freehand by Prosurgics

Camera holder

Small

Small

Low

Low

Small


The definition of different RCM is from:
Guanghua Zong, Xu Pei, Jingjun Yu, Shusheng Bi, Classification and type synthesis of 1-DOF remote center of motion mechanisms, Mechanism and Machine Theory, 43(12), Dec 2008, pp 1585-1595

*VESALIUS Robot is not currently cleared by the CE/FDA and so is limited to Investigational Use.
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