Title: A local hybrid actuator for robotic surgery instruments

Authors: Soheil Saedi; Alireza Mirbagheri; Ali Jafari; Farzam Farahmand

Addresses: Department of Mechanical Engineering, Sharif University of Technology - International Campus, Kish Island, Iran ' Robotic Surgery Lab., Research Centre of Biomedical Technology and Robotics, Tehran University of Medical Sciences, Keshavarz Blvd., Tehran, Iran ' Robotic Surgery Lab., Research Centre of Biomedical Technology and Robotics, Tehran University of Medical Sciences, Keshavarz Blvd., Tehran, Iran ' Department of Mechanical Engineering, Sharif University of Technology, Azadi st, Tehran, Iran

Abstract: A major problem in the design of miniature scale motorised endoscopic instruments is the actuation mechanism at the instrument's tip, especially when a high level of functionality and multi degrees of freedom (DOF) are concerned. In the present study, a new design for hybrid local-actuation of endoscopic instruments is proposed which includes a micro DC motor and a piezoelectric (PZT) actuator. A compact serial configuration was considered for the actuators. The DC motor provides the long movement course required for opening-closing function of the gripper while the PZT guaranteed the high gripping force needed for holding the needle. The efficacy of the design was evaluated in a simulation study using FEM, and it was shown that the needle holder is capable of applying a sufficiently high gripping force, up to 22 N. The feasibility of the design was further approved in experimental examination of a 4× scaled prototype of the instrument.

Keywords: biomechatronics; robotic surgery; hybrid actuation; local actuation; motorised instruments; piezoelectric actuators; surgical instruments; endoscopic instruments; endoscopy; medical instruments; micro motors; DC motors; surgical robots; robot grippers; PZT actuators; gripping force; simulation; FEM; finite element method; needle holders.

DOI: 10.1504/IJBBR.2014.064892

International Journal of Biomechatronics and Biomedical Robotics, 2014 Vol.3 No.2, pp.100 - 105

Available online: 20 Sep 2014 *

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