Development of an in-pipe inspection robot for narrow pipes and elbows using pneumatic artificial muscles

Pipe failures resulting from corrosion or other forms of deterioration are a common occurrence. To combat this problem, in-pipe inspections are required Fiberscopes are currently used as industrial endoscopes to inspect pipes for defects. However, because of friction, fiberscopes cannot be inserted into pipes that are more than 15 m long or have complex shapes such as elbows. Therefore, in-pipe inspection robots need to be self-propelling. In this study, we developed two robots that mimic the peristaltic crawling motion of earthworms as a locomotion mechanism. These robots consist of several units. Each unit has an artificial muscle that is driven by pneumatics. Each of the robots has an internal space to hold inspection apparatus. We conducted several experiments with a robot inside a 25A acrylic pipe (diameter: 27 mm). These experiments were conducted to examine the relationship between the locomotion speed and motion patterns. The robot was able to pass through the elbows that were positioned in both horizontal and vertical planes. In addition, we developed a smaller robot for a 15A pipe (diameter: 16 mm) to examine the relationship between the locomotion speed and motion patterns. Our findings exhibited good performance by the robots.