In the past few years, we have seen plenty of robots inspired by nature. iCrawl is an inchworm inspired crawling robot that relies on two legs each with an electromagnetic foot to crawl on metal pipe surfaces.
As the researchers explain:
The robot uses a passive footcap underneath an electromagnetic foot, enabling it to be a versatile pipe-crawler. The foot-cap design is an abstraction of the leg posture in an inchworm adapting to a round surface. The proposed foot-caps give the robot adaptability and stability for crawling on metal pipes of various curvatures.
They also used a state-machine based controller to produce step and sliding gaits.