A Three-rhombus Configured Remote Center of Motion Mechanism for Robot-assisted Surgery

Remote center of motion (RCM) mechanisms are widely utilized to achieve minimally invasive surgery (MIS) instead of manual operation. To realize the translation motion in an RCM mechanism, the proximal actuation method is generally adopted, which has the disadvantages of reducing the vision field, offsetting the RCM point, and increasing the moment of inertia. This paper proposes a surgery robot with a novel RCM configuration realized by a three-rhombus mechanism. The great merit of this robot is the actuators are all mounted on the base. The kinematics and singularity of the mechanism are investigated analytically. Parameter optimization is done under the given rotation angle of 90° and feed depth of 47.8 mm, respectively. Preliminary simulations are conducted in SolidWorks environment to validate the effectiveness of the RCM mechanism.