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Robotics

Soft robot movement speed inspired by cheetahs

North Carolina State University researchers have developed a type of soft robot capable of moving more quickly on solid surfaces or in the water, which was inspired by how cheetahs move.

By Matt Shipman May 17, 2020
Courtesy: North Carolina State University

Inspired by the biomechanics of cheetahs, North Carolina State University researchers have developed a type of soft robot capable of moving more quickly on solid surfaces or in the water. They’re also capable of grabbing objects delicately – or with sufficient strength to lift heavy objects.

“Cheetahs are the fastest creatures on land, and they derive their speed and power from the flexing of their spines,” said Jie Yin, an assistant professor of mechanical and aerospace engineering at North Carolina State University.

“We were inspired by the cheetah to create a type of soft robot that has a spring-powered, ‘bistable’ spine, meaning that the robot has two stable states,” Yin said. “We can switch between these stable states rapidly by pumping air into channels that line the soft, silicone robot. Switching between the two states releases a significant amount of energy, allowing the robot to quickly exert force against the ground. This enables the robot to gallop across the surface, meaning that its feet leave the ground. Previous soft robots were crawlers, remaining in contact with the ground at all times. This limits their speed.”

The fastest soft robots until now could move at speeds of up to 0.8 body lengths per second on flat, solid surfaces. The new class of soft robots, which are called “Leveraging Elastic instabilities for Amplified Performance” (LEAP), are able to reach speeds of up to 2.7 body lengths per second – more than three times faster – at a low actuation frequency of about 3Hz. These new robots are also capable of running up steep inclines, which can be challenging or impossible for soft robots that exert less force against the ground.

These LEAP robots are 7 cm long and weigh about 45 g.

The researchers also demonstrated that the LEAP design could improve swimming speeds for soft robots. Attaching a fin, rather than feet, a LEAP robot was able to swim at a speed of 0.78 body lengths per second, as compared to 0.7 body lengths per second for the previous fastest swimming soft robot.

“We also demonstrated the use of several soft robots working together, like pincers, to grab objects,” Yin said. “By tuning the force exerted by the robots, we were able to lift objects as delicate as an egg, as well as objects weighing 10 kilograms or more.”

The researchers note that this work serves as a proof of concept, and are optimistic that they can modify the design to make LEAP robots that are even faster and more powerful.

“Potential applications include search and rescue technologies, where speed is essential, and industrial manufacturing robotics,” Yin said. “For example, imagine production line robotics that are faster, but still capable of handling fragile objects. We’re open to collaborating with the private sector to fine-tune ways they can incorporate this technology into their operations.”

North Carolina State University

www.ncsu.edu

– Edited by Chris Vavra, associate editor, Control Engineering, CFE Media and Technology, cvavra@cfemedia.com.


Matt Shipman
Author Bio: Matt Shipman, research communications lead, North Carolina State University