Crawling is a useful method to move in narrow environments such as tubes or tunnels. Many crawling robots have been investigated that mimics peristalsis by inflating/shrinking thin elastic film while extending/contracting connected bodies.
However, elastic film-based actuation is vulnerable under harsh environments. In addition, inflation by air pressure requires a large air pump, which prohibits autonomy of a robot.
We propose a crawling mechanism that uses hard plate spring as inflators, which are driven by only a simultaneous twisting and extending motion performed by adjacent bodies.
Two types of units are proposed that inflate or shrink according to body twisting extension motion. By connecting these units and providing appropriate extension/contraction sequence, it is shown that the connected units perform crawling motion like peristalsis.
Since the robot allows liquid or air flow even if it inflates at maximum, this design would be suitable for inspection or cleaning task inside tube while operating the tube with flowing liquid.
