Designing Robot Footwear

Durable footwear for humans is just as important for robots.

With this in mind, we went to the experts in footwear-sole technology – Vibram – to help us develop a new footpad for our robot Digit.

“It doesn’t matter how sophisticated the robot is or the controller if the feet are sliding around,” said Andy Abate, a senior hardware engineer here at Agility Robotics.  “The tread design and the rubber compound selection are both fairly technical.”

Vibram has a reputation for crafting footwear soles that can hold up for miles. Their outsoles are often used on the footwear preferred for endurance sports like ultra marathons and mountain climbing. We recognized that just like extreme athletes, robots need footwear that can go the distance, too.

“The first question I had was, What was the gait of the robot? How did it walk?” said Jacob Baldry, a designer at Vibram. “Did it have a heel-strike, or a toe-strike? So figuring out the motions of the robots and seeing how similar they were to human footwear was the first consideration.”

Digit is a bi-pedal robot designed to work in human environments and assist workers with physically demanding, repetitive tasks that are meant for a machine. But the environments that humans work in can be hugely variable, requiring Digit to be able to adapt and continue moving smoothly, no matter the situation.

The designers at Vibram leant their expertise toward creating a tread pattern and rubber composition that would keep Digit stable, even on dusty, polished concrete which can be quite slippery. Digit’s new footwear looks a bit like a hiking boot sole but is rectangular in shape to match Digit’s feet.

“The feet are a really important part of Digit,” Abate said. “Vibram was incredibly helpful in helping us make these decisions.”

The overall result was increased stability and traction on a variety of surfaces and decreased wear, and we couldn't be happier.