Flexi-footed robot races across uneven ground
Image credit: University of California San Diego
Flexible robot feet have been developed by scientists, which allow robots to walk up to 40 percent faster on uneven terrain such as pebbles and wood chips.
Researchers from the University of California-San Diego envisage the feet being in applications for search-and-rescue missions or even space exploration.
“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 Emily Lathrop, the paper’s first author.
“Usually, robots are only able to control motion at specific joints,” said professor Michael T. Tolley. “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 feet are flexible spheres made from a latex membrane filled with coffee grounds. They allow robots to walk faster and grip better thanks to a mechanism called granular jamming which allows granular media (in this case, coffee grounds) to switch between behaving like a solid and a liquid.
When the feet hit the ground, they firm up, conforming to the ground underneath and providing solid footing, then loosening up when transitioning between steps. The support structures help the flexible feet remain stiff while jammed.
This is the first time that such feet have been tested on uneven terrain, like gravel and wood chips. The feet were installed on a commercially available hexapod robot. Researchers designed and built an on-board system that can generate negative pressure to control the jamming of the feet, as well as positive pressure to unjam the feet between each step.
As a result, the feet can be actively jammed, with a vacuum pump removing air from between the coffee grounds and stiffening the foot. But the feet also can be passively jammed when the weight of the robot pushes the air out from between the coffee grounds, causing them to stiffen.
Researchers tested the robot walking on flat ground, wood chips and pebbles, with and without the feet.
They found that passive jamming feet perform best on flat ground but active jamming feet do better on loose rocks. The feet also helped the robot’s legs grip the ground better, increasing its speed. The improvements were particularly significant when the robot walked up sloped, uneven terrain.
Meanwhile, another team of researchers from the University of Cambridge have trained a robot to prepare an omelette: from cracking the eggs to plating the finished dish.
“An omelette is one of those dishes that is easy to make, but difficult to make well,” said project leader Dr Fumiya Iida from Cambridge's Department of Engineering. “We thought it would be an ideal test to improve the abilities of a robot chef, and optimise for taste, texture, smell and appearance.”
The team used a machine learning technique that made use of a statistical tool, called Bayesian Inference, to squeeze out as much information as possible from the limited amount of data samples, which was necessary to avoid over-stuffing the human tasters with omelettes.
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