Development of active bending electric endoscope using shape memory alloy wire

A bending mechanism of conventional endoscope bends by traction of wires from outside the human body. A shaft structure of endoscope is relatively complex to avoid buckling by wire traction force. An active bending electric endoscope has been developed using SMA (shape memory alloy) wires. The SMA wires are driven by Joule heat provided electrical current to the wire. The active bending mechanism using SMA wires simplify bending mechanism of endoscope. A commercial CMOS imager and three LEDs at the tip of this device were mounted and a silicon rubber tube was connected the active bending mechanism using SMA wires as the shaft. This device accomplished multidirectional bending and the curvature radius was approximately 40 mm at 300 mA.