In order to seek a patient friendly and low-cost intestinal examination method, a structurally simple pneumatic soft intestinal robot inspired by inchworms is designed and manufactured. The intestinal robot was consisted of two radially expanding cylindrical rubber film airbags for anchoring and one low density polyethylene film airbag for axial elongation, which achieved movement in the intestine by mimicking the crawling of inchworms. Theoretical derivation was conducted on the relationship between the internal air pressure of the anchored airbag and the free deformation size after expansion, and it pointed out that the uneven deformation of the airbag was a phenomenon of expansion instability caused by large deformation of the rubber material. The motion performance of the intestinal robot was validated in different sizes of hard tubes and ex vivo pig small intestine. The running speed in the ex vivo pig small intestine was 4.87 mm/s, with an anchoring force of 2.33 N when stationary, and could smoothly pass through a 90 ° bend. This work expects to provide patients with a new method of low pain and low-cost intestinal examination.
