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Design, Fabrication and Control of a Force-Feedback-Enabled Robotic Instrument for Minimally Invasive Surgeries

Khadem, Mohsen | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44174 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Farahmand, Farzam; Behzadipour, Saeed
  7. Abstract:
  8. Aside from many advantages of minimally invasive surgery, it has some drawbacks. Surgeons` loss of dexterity dexterity, lack of force feedback and the consequent reduced sensation of forces are some of these drawbacks. Also, surgeons` ergonomically inappropriate posture gets him fatigued, causing hand tremor which is furthermore magnified by the long instruments. Robotic surgery systems have overcome some of minimally invasive surgeries limitations. But still some drawbacks such as high cost of maintenance or lack of haptic force feedback have impeded their widespread application. The high cost of maintenance is mostly caused by instrument changing and sterilization.The main goal of this project is to develop a sensor integrated modular and sterilizable laparoscopic instrument for minimally invasive surgeries. This instrument is used as the end-effector of a robot that is used as slave in a haptic master-slave robotic surgery system. This tele-surgery system is designed and fabricated in research center of science and technology in medicine at Imam Khomeini Hospital.Demands for lower cost of manufacture and maintenance can be met by developing a modular and sterilizable instrument. In this project, a sterilizable laparoscopic instrument is developed by incorporating commercial laparoscopic tools. The instrument consists of two detachable interfaces, one towards a surgery tool and the other towards the last arm of a surgical robot. Also the instrument includes a proximal force sensor and provides the crucial force feedback required for the haptic robotic surgery system. Other features of this instrument are: Tissue auto-grasp, control of angular position of instrument`s jaws, implementation of cautery. Cautery is a device used for destroying tissue using heat conduction from instrument tips heated by electric current.
    Furthermore, concept of auto grasp is introduced and used to control instrument/tissue contact forces. Main idea of auto grasp is to maintain a balance between pull and pinch forces exerted to soft tissue. This feature assists the surgeon by safely holding soft tissue while dissecting or stitching it. Besides by optimizing magnitude of instrument/tissue contact forces, auto grasp would significantly reduce robotic surgery trauma. Two different controllers based on two different method of force sensing (distal and proximal force sensing). Finally experiments were conducted to verify performance of controllers in achieving a safe, slip/damage free auto grasp. Also empirical results were used to ensure the instrument has met its design expectations
  9. Keywords:
  10. Robotic Surgery ; Force Control ; Robotic Laparascopic Instrument ; Emotional Controller ; Laparoscopic Surgery ; Soft Tissue Auto-Grasp

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