Much progress has been made in the robotics of soft robots, because they are more similar to human beings when it comes, for example, to pick up objects, but also to move.
And now researchers at North Carolina State University have presented a caterpillar-like robot, a soft robot that can move forwards, backwards and even enter very narrow spaces.
For this they were inspired by caterpillars and the different ways in which they move their bodies: “A caterpillar’s movement is controlled by the local curvature of its body. We have been inspired by the biomechanics of the caterpillar to mimic that local curvature and use nanowire heaters to control a similar curvature and movements in the robotic caterpillar.“, Explain zhuwho wrote the article with Andrew A. Adams, a professor of mechanical and aerospace engineering at NC State.
Thanks to the movement of this robot caterpillar, it can slide under very small gaps, such as under a door.
The caterpillar robot’s movement is powered by heating a system of small silver wires to control how the robot eventually bends.
“We show that the caterpillar robot is capable of pushing itself forwards and backwards. In general, the more current we applied, the faster it would move in either direction. However, we found that there was an optimal cycle, which gave the polymer time to cool down, allowing the muscle to relax before contracting again.“, says Shuang Wufirst author of the article and a postdoctoral researcher at NC State.
“If we tried to move the caterpillar robot too fast, the body didn’t have time to ‘relax’ before contracting again, impairing its movement. Engineering soft robots that can move in two different directions is a major challenge in the robotics soft”, he adds zhu.
How does this caterpillar robot work?
This robot has two layers of polymer that respond differently when exposed to heat.
The bottom layer shrinks or contracts when exposed to heat while the top layer expands when exposed to heat.
Then we have the silver nanowires that are embedded in the polymer layer, and where the pattern includes multiple main points where an electrical current can be applied.
In this way, the researchers can control the sections of the pattern of nanowires that end up being heated by applying an electric current at different connection points, and thereby control the amount of heat applied.
In this way they can control the forward and backward movement and also the height at which the robot slides and tilts.
“This approach to powering motion in a soft robot is highly energy efficient, and we are interested in exploring ways in which we could make this process even more efficient.Zhu says.
“Additional next steps include integrating this approach for locomotion of robots with sensors or other technologies for use in various applications, such as search and rescue devices”, he concludes.