An innovative locomotion principle for minirobots moving in the gastrointestinal tract

This paper illustrates a mechanism specifically designed for locomotion in the wet, collapsible and tortuous human gastrointestinal (GI) tract (the colon in particular). Previous works performed in the authors\´ laboratory were devoted to the fabrication of semi-autonomous inchworm locomotion devices for navigation in the colon; in this paper a further analysis of limitations and problems of these devices has been performed. The main limitation consists of the poor efficiency of these devices to negotiate acute bends (due to what the authors termed as the "accordion effect") and, in general, to advance in the scarcely supported colon tissue. Thus a different approach to locomotion has been developed based on "sliding clampers". This locomotion principle has been implemented in a minirobot system and has demonstrated (both theoretically and experimentally) to be effective in reducing the "accordion effect"