Design and Validation of a Passive Motion Scaling Mechanism Prototype for Microsurgery

Since the advent of the commercial da Vinci surgical system, microsurgical robotic systems have been increasingly investigated. These systems improve the accuracy and dexterity of surgeries using a computerized motion scaling function between a surgeon’s hand and surgical instrument. However, the manufacturing process of these systems is expensive owing to the use of multiple sensors, actuators, and controllers. Additionally, certain limitations exist, such as an increase in the size of the operating room to accommodate the robotic system and the absence of tactile force feedback. To address these problems, we propose a passive motion scaling mechanism for microsurgery. Based on the pantograph mechanism, we downscale the linear displacement of the surgeon’s hand and transfer it to the surgical instrument. Furthermore, the rotational displacement of the surgeon’s hand in an actual surgery is transmitted to the surgical instrument on a 1:1 scale by applying a parallelogram mechanism. We designed and fabricated a prototype capable of transmitting linear and rotational displacements (pitch and yaw) of the surgeon’s hand with three degrees of freedom (DOFs) and two DOFs, respectively, by combining the two mechanisms. The obtained experimental results verify the motion scaling function of the developed prototype.