Imagine you are at the movies and you see a Roomba-like robot climbing a wall or clinging to a ceiling. How would that work? If you are like us, you might think of suction cups or something mechanical or magnetic in the wall. Then again, it is a movie, so maybe it is just a camera trick. The robots from the Bioinsipired Robotics and Design Lab at UCSD are no camera trick, though. As [Evan Ackerman] mentions in a post on IEEE Spectrum, “It’s either some obscure fluid effect or black magic.” You can watch a video about the bots, below.
It turns out, the answer is closer to a suction cup than you might think. According to the paper from the lab, a small flexible disk vibrates at 200 Hz. This generates a thin (less than 1 mm) layer of low pressure air in between the disk and the underlying surface. The robot can resist a force of up to 5 newtons from the suction from the disk.
The disk is only 14 cm in diameter, so somewhere around the size of a common saucer. This seems like something that would be simple to replicate with your own robots. The biggest problem is noise. At 200 Hz, you will hear this robot coming. It also looks like scaling up or down could be a problem. Too small, and the motor that drives the eccentric weight eats up too much space. Larger, you have more to support. We wondered if a piezoelectric disk would work.
We are looking forward to seeing a homebrew robot based on this technique. We have seen other wall climbing robots, of course. Some can even fly.
Maybe it could be scaled up by using many saucer sized disks connected in a lattice of some sort. With enough disks to have redundancy, a robot could transition across different height and angle surfaces, maybe even going from vertical to horizontal surfaces. Or like a lizard or even a snake configuration.
Now instead of just 1 disc:
– make it multiple discs per leg for redudancy
– add 8 legs in a spider configuration
– scale it up to truck size
– add AI for good measure
– reduce the frequency to 80 for better scare factor
This would be a good recipe for a doomsday robot in a movie :D
Thanks, ordering the parts from china right now)
Half a ton, vibrating at 200Hz, hanging off your wall.
Apart from the racket, that would make for a very efficient plaster removing machine!
Send in the video when you have one :)
That is really fun, and potentially very useful effect.
But I don’t want one anywhere near me, annoying buzzing in audible range just isn’t for me when it comes to robots. Wonder what frequencies work, and how changing frequencies interacts with disk material and size, and ambient pressure for that matter. Would rather suck if your robot climibing machine fell off once the atmospheric pressure dropped through temperature swings or just climbing high enough…
cool if you live in a glass house i guess.
Seems like it’s usage would be limited to smooth polished surfaces. Wonder if you could use harmonic freq. to get around the sound problem.