Active bending electric endoscope usine shape memory alloy coil actuators

Wataru Makishi, Tadao Matsunaga, Masayoshi Esashi, Yoichi Haga

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Bending motions of the tip of a conventional endoscope are controlled from outside the body by wire traction. A shaft of an endoscope should be relatively hard to avoid buckling by wire traction. Therefore, precise operation of the endoscope is difficult in complex shape areas such as the intestine. Furthermore, patients suffer pain during a procedure with an endoscope. An active bending electric endoscope using shape memory alloy (SMA) actuators has been developed. A CCD camera (410,000 pixels) is mounted at the end of the endoscope and the tip has an omni-directional bending mechanism using three SMA coil actuators. The SMA coil actuators contract by supplying electrical current and bend the endoscope. The external diameter of the fabricated endoscope is 5.5 mm. The maximum bending angle of the fabricated endoscope is 90° (Curvature radius: 29 mm). The observation of the inside of a blood vessel model by the CCD imager of a fabricated endoscope was confirmed. The active bending shaft of the fabricated endoscope, which is realized using SMA coil actuators instead of wire traction, is soft. Therefore, using this endoscope, it may be possible to perform precise observations and treatment of deep areas of the human body.

Original languageEnglish
Pages (from-to)75-81+5
JournalIEEJ Transactions on Sensors and Micromachines
Issue number2
Publication statusPublished - 2007


  • Active bending mechanism
  • CCD camera
  • Electric endoscope
  • SMA actuator


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