Robotic 'cheetah' might not look like the animal but borrows its mechanics

Though best known for their speed, cheetahs are also remarkably efficient runners, making them animals of interest for roboticists who want to replicate that energy efficiency in their machines. Five years ago, engineers in Massachusetts Institute of Technology’s Biomimetic Robotics Lab created a 70-pound robot that rivaled the energy-efficiency of the real thing.

Now, an engineer from the University of Twente in the Netherlands has created a robot prototype that doesn’t quite look like a cheetah but exploits the animal’s running mechanics for increased efficiency.

“I noticed that [the MIT roboticists], like BostonDynamics, took inspiration from the cheetah by copying its shape and then trying to make it run,” Geert Folkertsma, the robot’s creator, told Digital Trends. “They made two awesome robots but still I thought, ‘We’re actually trying to copy the way it runs — the speed, the energy-efficiency — and not the way it looks.

To create his prototype, Folkertsma studied video footage and used software to pin down the nuances of cheetah movement.

“I think the efficient, graceful motion of the cheetah is very inspirational,” he said. “Robots cannot yet come close to matching it. My goal was to study the dynamics of the cheetah locomotion, to understand how it runs so fast and efficiently, and then to transfer those dynamic principles to a robot.”

Folkertsma confirmed that much of a cheetah’s efficiency comes from the flexibility of its spine, and he thinks he’s determined the properties that make its movement so seemingly effortless.

“The effect of the spine turned out to be very important,” he said. “It can be modeled like a spring, which was already known to some researchers, but I found out that the specific geometric properties of the spring — where is it located, what is its stiffness — can in fact lead to locomotion, without doing any sort of complicated control on the motors.

University of Twente / Geert Folkertsma

“The result is a robot that does not look like a cheetah very much, other than having four legs and a spine, but the way it runs, the dynamics, are in fact very similar,” he added.

Folkertsma’s five-and-a-half-pound cheetah is still very much a work in progress. It’s current stop speed is less than one mile per hour and it still uses about 15 percent more energy than its living counterpart. However, the engineer thinks that his research presents a path forward for more energy-efficient robots.

“There are more quadrupedal robots, some even with a spine, but it is usually placed quite arbitrarily somewhere between the front and rear part,” he said. “My study shows that, by placing it a bit more carefully, the control of the robot becomes much easier, and its efficiency and speed are likely increased as well.

“As for robots without a spine,” he added, “well, they stand to gain a lot by adding one.”