Development of a Practical Articulated Wheeled In-pipe Robot for Both 3-4 in Force Main Inspection of Sewer Pipes

TL;DR

This paper introduces AIRo-7.1, a practical, adaptable in-pipe inspection robot capable of navigating 3-4 inch sewer pipes, with a focus on its design, control system, and successful field testing.

Contribution

The paper presents a novel, compact articulated wheel robot with adjustable joint torque and a simple control system, enabling effective sewer pipe inspection across various diameters.

Findings

High adaptability to different pipe diameters confirmed

Successful navigation in vertical, bend, and diameter change sections

Field tests demonstrated practical inspection capabilities

Abstract

This paper reports a practical articulated wheeled in-pipe inspection robot "AIRo-7.1" which is waterproof and dustproof, and can adapt to 3 to 4 in inner diameters. The joint torque can be adjusted by a PWM open-loop control. The middle joint angle can be controlled by a position feedback control system while the other two joints are bent by torsional springs. Thanks to this simple and high-density design, not only downsizing of the robot but also wide range of the adaptive inner diameter were achieved. However, the relationship between the actual middle joint torque value and the PWM duty ratio should be pre-known because the reducer used in AIRo-7.1 was designed by ourselves. Therefore, preliminary experiments were conducted to clarify the relationship between them. To examine the adaptive movement, experiments in both 3 in and 4 in pipes with vertical, bend, and diameter change sections. Finally, field experiment was also conducted. From the results, high adaptability to different inner diameters of pipes and slippery environments were confirmed although waterproof and dustproof were not perfectly working.