Development of Distance Measurement System Using Ar Laser under Water

摘要

For positioning measurement of an underwater vehicle robot in a reactor pressure vessel for ultrasonic inspection of the vessel, we developed distance measurement system using pan/tilt mechanisms to control directions of an argon gas laser and outgoing/incoming lights. This can automatically measure three-dimensional position and follow of the underwater vehicle robot up to 0.5 ppm water turbidity, this is the first of its kind in the world. This system can measure up to maximum length measuring distance of 8.5 m underwater, within a +-3.6 mm error. We adopted the power 75 mW output for argon gas laser modulated at 80MHz, and a detector with resolution of 0.004 degree for the pan/tilt mechanisms.