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Design, Analysis, and Experimental Study of a Slave Robot for Minimally Invasive Beating Heart Surgery

Alamdar, Alireza | 2020

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 52666 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Farahmand, Farzam
  7. Abstract:
  8. In this study, a practical approach for robotic beating heart surgery was proposed. This approach eliminates lateral movements of the heart and compensates for normal heart movement by using 1 DOF heart stabilizer and 1 DOF heart compensator simultaneously. It is a compromise between complete fixation of the heart, which damages the heart tissue, on one hand and complex and impractical compensation of the free heart movement on the other. One of the core components of the proposed system is the slave robot, which includes a 1 DOF compensator and a 4 DOF tool holder robot. Based on the selected laparoscopic tool, a modified agile-eye mechanism for activating the wrist was introduced, analyzed, and implemented. Also, a new geometrical method was proposed to analyze the kinematics and singularities of this mechanism. Finally, the dimensional optimization of the asymmetric agile-eye mechanism, including determination of the mechanism link lengths and its base positioning, was performed, the prototype of the tool was fabricated and its performance was evaluated. The results of the functional tests on the tool holder robot indicate high robot repeatability as well as maximum and RMS tracking error of 0.52 ± 0.02 and RMS 0.27 ± 0.01 degrees, respectively. The error is expected to be greatly reduced by kinematic calibration. Furthermore, a dynamic model for the slave robot is presented and its parameters are identified and validated. The results of the dynamic model validation test showed that this model exhibits good behavior, up to the first natural frequency of the system which is satisfactory since the vibration model between the compensator and the tool holder is 1 DOF. Finally, the performance of the compensator-stabilizer set was evaluated. During this test, the position of the surface of the silicon heart (connected to the simulator) and the tip of the instrument were recorded, the error and delay rates evaluated, and the delay and error factors were identified. The delay and RMS error between the displacement signal of the heart surface and the instrument tip was 62ms and 0.77mm, respectively, which can be reduced to 0.17mm assuming that the delay can be removed using a perfect prediction algorithm
  9. Keywords:
  10. Wristed Laparoscopic Instraments ; Coronary Artery Bypass ; Coronary Arteries Disease (CAD) ; Robotic Surgery ; Heart Motion Compensation ; Robotic Beating Heart Surgery

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