Active bending electric endoscope using shape memory alloy wires

Abstract

The bending mechanism of a conventional endoscope operates by drawing wires from outside the human body. The shaft structure of endoscopes is relatively complex to avoid buckling by the tensile force of the wire. Therefore, it is difficult to make a conventional endoscope. In this study, an active bending electric endoscope was developed using SMA (shape memory alloy) wires. The SMA wires are driven by Joule heat generated by electric current. As a result, the shaft structure of the active bending mechanism is simplified compared to the conventional endoscope. The active bending mechanism using SMA wires simplifies inspection inside the human body. This device consists of a commercial CMOS imager, three LEDs and a shaft structure. It is capable of multidirectional bending with a curvature radius of approximately 40 mm at 300 mA. The active bending mechanism using SMA wires would be suitable for construction of a disposable endoscope.