• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2018, Vol. 54 ›› Issue (17): 28-35.doi: 10.3901/JME.2018.17.028

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Deployable Manipulator with Tunable Stiffness for Natural Orifice Transluminal Endoscopic Surgery

ZHANG Guokai1,2, MA Jiayao1,2, SHANG Zufeng1,2, CHEN Yan1,2, YOU Zhong3, YI Bo4, WANG Shuxin1,2   

  1. 1. Key Laboratory of Mechanism Theory and Equipment Design of the Ministry of Education, Tianjin University, Tianjin 300350;
    2. School of Mechanical Engineering, Tianjin University, Tianjin 300350;
    3. Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK;
    4. The Third Xiangya Hospital of Central South University, Changsha 410013
  • Received:2018-01-17 Revised:2018-04-25 Online:2018-09-05 Published:2018-09-05

Abstract: Natural orifice transluminal endoscopic surgery (NOTES) has great potential in clinical applications due to its shorter and better recoveries, less trauma and postoperative pain compared with open surgery. In NOTES, a long manipulator is always placed through a tortuous human orifice to create a channel for surgical instruments and provide support when they are operated. Currently most manipulators have a large profile and low stiffness, and therefore are not able to meet the requirements of NOTES. A new deployable manipulator with tunable stiffness is proposed. The manipulator takes a braided structure to achieve radial deployment/folding, whereas hot melt adhesive is placed at the intersection points of the structure to adjust its stiffness. A mathematical model is built to calculate the stiffness in the rigid and flexible states, respectively. Experimental results demonstrate that by heating and cooling the adhesive, a flexible and a rigid states are achieved, and the ratio of bending stiffness in the rigid state to that in the flexible state reaches around 20. The stiffness switch is complete in less than 30 s. In addition, a deployable over folding ratio of around 2 is also achieved.

Key words: braided structure, deployment/folding ratio, manipulator, natural orifice transluminal endoscopic surgery, tunable stiffness

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