Cockroach-inspired robot negotiates obstacles
23 June 2015
Researchers at University of California, Berkeley have taken inspiration from the cockroach to create a robot that can use its body shape to manoeuvre through densely cluttered environments.
Fitted with the characteristic rounded shell of the discoid cockroach, the running robot can perform a roll manoeuvre to slip through gaps between vertical beam obstacles without the need for additional sensors or motors.
It is hoped the robot will inspire the design of future terrestrial robots for use in scenarios from monitoring the environment to search and rescue operations.
Lead author of the study Chen Li, from the University of California, Berkely, said: “The majority of robotics studies have been solving the problem of obstacles by avoiding them, which largely depends on using sensors to map out the environment and algorithms that plan a path to go around obstacles. However, when the terrain becomes densely cluttered, especially as gaps between obstacles become comparable or even smaller than robot size, this approach starts to run into problems as a clear path cannot be mapped.”
To solve this problem the researchers used high-speed cameras to study the movement of discoid cockroaches through an artificial obstacle course of vertical beams with small spacing. The cockroaches were fitted with different artificial shells to see how their movement was affected by body shape when moving through the vertical beams. The shapes of the three shells were an oval cone with a similar shape to the cockroaches’ body; a flat oval; and a flat rectangle.
When the cockroaches were unmodified, the researchers found that, although they sometimes pushed through the beams or climbed over them, they most frequently used a fast and effective roll manoeuvre to slip through the obstacles. In these instances, the cockroaches rolled their body so that their thin sides could fit through the gaps and their legs could push off the beams to help them manoeuvre through the obstacles.
After examining the cockroaches, the researchers then tested a small, rectangular, six-legged robot and observed whether it was able to traverse a similar obstacle course. The researchers found that with a rectangular body the robot could rarely traverse the grass-like beams, and frequently collided with the obstacles and became stuck between them.
However, when fitted with the cockroach-inspired rounded shell, it was much more likely to successfully move through the obstacle course using a similar roll manoeuvre to the cockroaches. This adaptive behaviour came about with no change to the robot programming, showing that the intelligent behaviour came from the shell.
“We showed that our robot can traverse grass-like beam obstacles at high probability, without adding any sensory feedback or changes in motor control, thanks to the thin, rounded shell that allows the robot body to roll to reduce terrain resistance.” Continued Li. “There may be other shapes besides the thin, rounded one that are good for other purposes, such as climbing up and over obstacles of other types. Our next steps will be to study a diversity of terrain and animal shapes to discover more terradynamic shapes, and even morphing shapes.
These new concepts will enable terrestrial robots to go through various cluttered environments with minimal sensors and simple controls.”
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