Design and prototyping of a soft earthworm-like robot targeted for GI tract inspection

In this paper we present a pneumatic driven soft earthworm robot targeted for gastrointestinal (GI) tract inspection. The robot contains two expanding sections and one extending section with bending function. This allows the robot crawling through tubular environment such as the colon. Pressure inside the actuators are monitored as well, which enables to regulate the PWM delivered to the robot. Three different versions of our robots are prototyped and tested using PVC tube and ex vivo pig colon. Results show that all the robots could crawl effectively in PVC tube with the speed of 1.34 mm/s, 0.7 mm/s and 1.5mm/s respectively. The robot could also crawl through steep slopes without slowing down. The maximum drag force of the soft robot in PVC tube is 4.7 N.