A Standards-based Pipeline Route Drawing System using a Towed Sensing Unit

Abstract

This paper presents a method of drawing pipeline routes using a sensing unit with a rotary encoder and IMU (Inertial Measurement Unit), which is towed by a self-propelled in-pipe inspection robot. However, the IMU information generally contains integration errors, making it difficult to draw accurate pipeline routes. In this study, we propose a method combining gradient descent using a gyroscopic sensor and an accelerometer, and the correction of the route based on the standard information of the pipe. First, the method of identifying the start point, end point, direction of straight pipes, and bending direction of curved pipes is explained. Then, an experiment is conducted using the developed robot system on a 11.6-meter-long pipeline course that includes nine curved pipes and horizontal and vertical straight pipes. Consequently, the mean absolute error of the route dimension was reduced to 2.74 %.