Taking inspiration from snakes and worms, which can easily traverse both flat and obstacle-filled surfaces, researchers from the University of Southern Denmark (SDU) have built a bioinspired soft robot that mimics the movements of these limbless animals.
The robot is capable of moving in a straight line up to 0.03 mph while navigating complex environments, such as those featuring relatively tight turning circles.
Source: SDU
To move, the robot uses its body to gain traction with the ground. Specifically, the team relies on inflatable soft actuators that are arranged in an antagonistic manner, so that they work against each other.
This arrangement reportedly enables the robot to mimic the earthworm’s ability to move using a phenomenon called anisotropic anchoring wherein tiny appendages on the earthworm’s skin — called setae — enable it to gain purchase on a surface and thus achieve movement.
As such, the robot’s body is encased in a kirigami skin, which is a patterned, flexible material that produces asymmetric friction that functions like an earthworm’s setae, enabling the robot to apply different resistance in various directions.
Altogether, these features allow the robot to achieve rectilinear motion — or straight crawling. This is accomplished, according to the researchers, by inflating chambers in sequence while steering is achieved via asymmetric gaits that allow for rotation or turning.
Further, the robot features a network of onboard proximity sensors for detecting and analyzing its surroundings. A human machine-interface (HMI) issues actual commands, which allows a human to guide or modify movement in real-time.
In addition to its potential use in autonomous exploration in unpredictable settings, the team suggests the robot might also be capable of navigating collapsed buildings or pipes, or of conducting search-and-rescue operations in rubble, exploring confined areas, monitoring environments or inspecting hard-to-reach industrial spaces.
An article detailing the robot, “Multimodal Limbless Crawling Soft Robot with a Kirigami Skin,” appears in the journal Cyborg and Bionic Systems.
For more on the robot, watch the accompanying video that appears courtesy of SDU.
