US engineers have developed a 3D-printed, four-legged robot that is capable of walking on rough surfaces, such as sand and pebbles, the University of California San Diego (UCSD) stated on Tuesday.

Researchers led by Michael Tolley, a mechanical engineering professor at UCSD, will present the robot at the IEEE International Conference on Robotics and Automation scheduled for May 29-June 3 in Singapore.

The soft-legged robot can climb over obstacles and walk on different terrains. It could also be used to capture sensor readings in dangerous environments or for search and rescue, researchers said.

According to the UCSD, the legs of the robot are made up of three parallel, connected sealed inflatable chambers, or actuators, 3D-printed from a rubber-like material. The chambers are hollow on the inside, so they can be inflated. On the outside, the chambers are bellowed, which allows engineers to better control the legs' movements.

The breakthrough was made thanks to a high-end printer that allows researchers to print both soft and rigid materials within the same components, which according to Tolley can help to make a new generation of robots, which are fast and agile, and more adaptable than their predecessors.

He said the idea came from nature.

"In nature, complexity has a very low cost," Tolley said in a statement. "Using new manufacturing techniques like 3D printing, we're trying to translate this to robotics."

Dylan Drotman, a Ph.D. student at the Jacobs School of Engineering at UCSD, led the effort to design the legs and the robot’s control systems, according to UCSD. He also developed models to predict how the robot would move, and then made a comparison between the prediction and the robot’s actual movements in a real-life environment.

This robot surpasses the current soft robots in that it can actually walk while others have only been able to shuffle or crawl on the ground without lifting their legs.