Scientists at the University of California San Diego have invented new coffee-filled robot feet that can help the machines walk up to 40% faster even on uneven terrain. This, it seems, is a very useful skill for robots.
"Robots need to be able to walk fast and efficiently on natural, uneven terrain so they can go everywhere humans can go, but maybe shouldn't," said in a statement Emily Lathrop, the paper's first author and a Ph.D. student at the Jacobs School of Engineering at UC San Diego.
"Usually, robots are only able to control motion at specific joints," added Michael T. Tolley, a professor in the Department of Mechanical and Aerospace Engineering at UC San Diego and senior author of the paper. "In this work, we showed that a robot that can control the stiffness, and hence the shape, of its feet outperforms traditional designs and is able to adapt to a wide variety of terrains."
The novel feet are made from a latex membrane filled with coffee grounds that allows robots to walk faster and grip better. This is all due to something called "granular jamming," a mechanism that allows granular media, i.e. the coffee grounds, to alternate between a solid and a liquid state.
When these feet hit a solid foundation, like the ground, they firm up. When they are lifted back in the air then unjam and loosen up.
If that's not impressive enough, the roboticists invented an on-board system that can control the feets' jamming level using a vacuum pump that removes air from between the coffee grounds.
Researchers installed the feet on a commercially available hexapod robot and tested them on flat ground, wood chips and pebbles. They found that the coffee-filled feet helped the robot's legs grip the ground better, particularly when it walked up sloped, uneven terrain. This significantly increased the machine's speed.
"The natural world is filled with challenging grounds for walking robots -- slippery, rocky, and squishy substrates all make walking complicated," said Nick Gravish, a professor in the UC San Diego Department of Mechanical and Aerospace Engineering and study coauthor. "Feet that can adapt to these different types of ground can help robots improve mobility."