High-speed response of the pneumatic actuator used in a peristaltic crawling robot inspecting long-distance gas pipes

Abstract

At present, city infrastructures are supported by buried gas pipes. Recently, to prevent gas leakage from old gas pipes (which can lead to accidents), routine inspections are required. However, current inspection methods require enormous cost and time. To solve this problem, researchers have developed various pipe inspection robots; however, these robots have difficulty climbing or maneuvering through narrow pipes. Therefore, we focused on the peristaltic crawling of an earthworm. This motion provides a large contact surface area in small spaces, enabling movement through narrow pipes. Therefore we developed a peristaltic crawling robot. It is installed with a straight-fiber-type artificial muscle and is driven by a fire-safe pneumatic system. However, delaying air transmission reduces the velocity of the robot. Considering the costs of hiring workers and the problems created by incidents such as roadblocks, a short inspection time is desired. Installing a solenoid to increase the robot's velocity is impractical in gas pipes because it increases the fire risk. Therefore, we propose an air discharge hole on-off mechanism and instant-supply high pressure and confirm their efficacy in the present study.