There has been a lot of development on Robots in recent times. This time we have engineers at the University of California San Diego creating a four-legged soft robot that doesn’t need any electronics to work. All the new robot needs is a constant source of pressurized air for its functions, including controls and locomotion systems.
Led by Michael T. Tolley, a professor of mechanical engineering at the Jacobs School of Engineering at UC San Diego, published the work in the issue of the journal Science Robotics.
Dylan Drotman, a PhD student in Tolley’s research group and the paper’s first author, said this research is an important step towards fully autonomous, electronics-free walking robots.
We can use these robots in low-cost robotics like toys and in cases where electronics cannot function like MRI machines or mine shafts. Soft robots adapt easily to their environment and operate safely near humans.
Most of them are powered by pressurized air and controlled by electronic circuits. Such an approach of using the air requires complex components often outside the robot’s body. The components are also bulky and costly.
However, the newly developed robot is controlled by a light-weight, low-cost system of pneumatic circuits, made up of tubes and soft valves, onboard the robot itself. It can also walk on command and respond to signals from its senses.
The team said that their focus was to make the simplest air-powered nervous system needed to control walking.
The team also added that the inspiration for this was from neural circuits found in animals, called central pattern generators, made of very simple elements that can generate rhythmic patterns to control motions like walking and running.
To mimic the generator’s functions, engineers built a system of valves that act as oscillators, controlling the order in which pressurized air enters air-powered muscles in the robot’s four limbs. They built a component that coordinated the robot’s gait by delaying the injection of air into the robot’s legs.
The Science Robotics paper builds on previous work by other research groups that developed oscillators and sensors based on pneumatic valves, and adds the components necessary to achieve high-level functions like walking.
While coming to its working, as we see the robot is equipped with three valves acting as inverters causing a high pressure state to spread around the air-powered circuit, with a delay at each inverter.
Each of the robot’s four legs has three degrees of freedom powered by three muscles. The legs, angled downward at 45 degrees, are composed of three parallel, connected pneumatic cylindrical chambers with bellows. When a chamber is pressurized, the limb bends in an opposite direction. The result, the three chambers provide the multi-axis bending required for walking.
A soft valve switches the direction of rotation of the limbs between counterclockwise and clockwise.
Researches want to improve the robot’s gait so that it can walk on natural terrains and uneven surfaces.
The team will also look at how the technology could create robots, which are in part controlled by pneumatic circuits for some functions, such as walking, while traditional electronic circuits handle higher functions.
Dylan Drotman, Saurabh Jadhav, David Sharp, Christian Chan, Michael T. Tolley. Electronics-free pneumatic circuits for controlling soft-legged robots. Science Robotics, 2021; 6 (51): eaay2627 DOI: 10.1126/scirobotics.aay2627