Last updated February 20, 2018 at 2:46 pm
US researchers have been inspired by snakes to develop a new type of robot movement
In the Venn diagram of science, the overlap between robots and snakes is probably pretty small. Yet scientists have used the slithery stuff of nightmares as inspiration, creating flexible scaly skins that allow immobile soft robots to crawl.
Combining inspiration from the reptiles and the ancient Japanese paper cutting art of kirigami, they came up with cost-effective textured skins capable of manoeuvring through even rough surfaces such as asphalt and concrete.
It is thought the new method of locomotion can open new avenues for robots working in search-and-rescue, exploration, environmental monitoring and medical fields.
The “anatomy” of the robotic crawler, inspired by the motion of snake scales. Click to enlarge. Credit: Carla Schaffer / AAAS
Soft robots – advantages, but fatally flawed
Soft robots are easy and inexpensive to fabricate, and able to achieve complex motions.
However, in order to move most require multiple connected parts that are each independently controlled.
What’s more, they are typically smooth on the outside and as a result can’t generate enough friction on surfaces to push forward on their own.
Researchers from Harvard University looked to kirigami as way of developing stretchable and morphable structures which they could use as a skin to provide that friction and push.
Related: The 10 biggest challenges facing robotics
The researchers were inspired by the scaly skin of snakes, which grips onto surfaces to provide the friction needed to move its body forward.
Using kirigami techniques, they developed skins covered in scales which they could wrap around tube like robots containing air-powered actuators.
Inflating the actuator caused the laser-cut scales to pop up away from the front of the robot and grip it to the ground, enabling forward movement.
Deflation flattened the scales, except at the head, where they stayed anchored to prevent backward sliding.
The end result was a snake-like slither forwards by rhythmic inflation and deflation of the actuator causing gripping and sliding of the scales.
Trapezoidal scales on the robotic crawler. Credit: Ahmad Rafsanjani/ Bertoldi Group/ Harvard University
Robots that slither like a snake
The researchers found that altering the shape of the scales – either triangular, circular, trapezoidal or linear – allowed them to change the speed and efficiency of crawling.
For example, trapezoidal cuts were more flexible than other shaped cuts, enabling the crawler to achieve a longer stride.
After proving the concept using robots connected to an air pump system, the researchers then built prototype robots which were not connected to external equipment.
These prototypes were truly independent, containing on-board motor control, power supplies and sensing devices.
Rather than just being used to terrorise friends and family, the researchers think the small robots capable of moving over most surfaces will be especially useful for search and rescue, medical uses, and, most encouragingly, environmental monitoring.
Their size and streamlined nature means they would be able to reach locations denied to other robots relying on wheels, legs or more dramatic changes in shape.
The research has been published in Science Robotics
