We've been hearing a lot lately about robots that are designed to operate in hazardous environments such as disaster sites. In these types of places, it's entirely possible that their locomotion system could be damaged. Would that just stop them in their tracks? Perhaps not, if they're anything like the brittle star-inspired robot created at Japan's Tohoku and Hokkaido universities.
A close relative of the starfish, the brittle star lacks a central nervous system, and has an interesting defense mechanism – if a predator grabs one of its five flexible arms, the brittle star can simply self-amputate that arm and regrow it later. In the meantime, it's immediately able to move on in whichever direction it wishes, very quickly adapting to the loss of the limb. This is the case even if multiple arms are lost.
After studying brittle star behaviour in the lab, a team led by Tohoku's Prof. Akio Ishiguro designed a five-armed robot that works in much the same way.
It has sensors in each of its arms, which measure reactive force as that arm "kicks" against the ground. As long as that force moves it in the desired direction, that arm continues to kick. Should the arm be damaged/amputated and is no longer able to move the robot correctly, however, it simply stops kicking. The robot then re-coordinates the movements of its remaining arms, to maintain its heading.
What's more, it's able to adapt to the damage within a few seconds, as opposed to the tens of seconds required by some other experimental adaptive robots.
A paper on the research was recently published in the journal Royal Society Open Science. You can see the robot in action, in the following video.
Source: Tohoku University