Four-Legged Robot Operates Without Electronics

In one of the latest advancements in the field of robotics, a team of engineers at the University of San Diego has developed a four-legged soft robot that can operate without any electronics. Instead, it relies on pressurized air for all of its controls and locomotion systems. 

Michael T. Tollet, a professor of mechanical engineering at the Jacobs School of Engineering at UC San Diego, led the team and its research. It was published in Science Robotics on Feb. 17.

Tollet was joined by Dylan Drotman, a Ph.D student in the research group and first author of the paper.

“This work represents a fundamental yet significant step towards fully autonomous, electronics-free walking robots,” Drotman said.

The Robot

The major difference between the newly developed robot and existing soft robots is that the later, while also powered by pressurized air, relies on electronic circuits. Because of this, there are many complex components involved like circuit boards, valves, and pumps that are located outside the robot’s body. The electronic components are crucial to the robot, acting as the brain and nervous system, and given their importance, they are often expensive and take up a lot of space. 

The newly developed robot by the UC San Diego team instead relies on a lightweight and inexpensive system of pneumatic circuits. The system consists of tubes and soft valves, which are located on the actual robot. With the system, it can respond to signals from the environment and walk on command. 

“With our approach, you could make a very complex robotic brain,” Tolley said. “Our focus here was to make the simplest air-powered nervous system needed to control walking.”

Four Legs, Three Degrees of Freedom Each

The robot has air-powered muscles in its four limbs, where pressurized air controlled by valves enters. It also consists of mechanical sensors in the form of soft bubbles filled with fluid located on the body. Reverse direction can be achieved in the robot when the bubbles are depressed, which results in the fluid flipping a valve in the robot. 

The robot has four legs, with three degrees of freedom and three muscles. They consist of three parallel, connected pneumatic cylindrical chambers with bellows, and the legs are angled downward at 45 degrees. 

The limbs of the legs can be bent in the opposite direction when a chamber is pressurized, meaning each one has multi-axis bending that enables walking. With a soft valve, the direction of rotation of the limbs can be switched between clockwise and counter-clockwise. 

The researchers will now look towards using the robot on natural terrain and uneven surfaces, which requires a more complex network of sensors and pneumatic system.