Making pipe-undulation shape measurement highly accurate by a pipe inner-wall shape sensor

Abstract

We have investigated reconstruction of the pipe-undulation shape throughout the length of a pipe from the measured data of the interior profiles by using a laser-beam scanning sensor. This sensor has been studied for detailed noncontact mapping of the interior geometry of pipes. The sensor, which is based on the optical triangulation, employs a laser-beam scanner placed between a laser diode and a position sensor. In this article, we study on three error factors to make pipe-undulation shape measurement highly accurate. First, we considered errors (a) caused when there is no gravitational sensor (when there is difference between the measuring direction and the perpendicular (starting) direction ). Next, we study errors (b) caused by vibration while running. In the last, we checked errors (c) caused by trip-meter outputs. We find that errors (a) and (b) are comparable, and large enough to influence the pipe-undulation shape measuring results. And the errors (c) are small compared to the errors (a) and (b).

Keywords

• curvature measurement
• curved pipe
• pipe interior geometry mapping
• laser-beam scanning sensor
• optical triangulation