It’s usually the simple ideas that sprout bigger ones, and this was the case when we saw [gzumwalt]’s single-motor walking robot crawling up a fridge door with magnets on its feet. (Video, embedded below.)
The walking mechanism consists of an inner foot and two outer feet, connected by three sets of rotating linkages, driven by a single geared motor. The feet move in a leapfrog motion, in small enough steps that the center of mass always stays inside the foot area, which keeps it from tipping over. Besides the previously mentioned ability to crawl around on a vertical magnetic surface, it’s also able to crawl over almost any obstacle shorter than its step length. A larger version should also be able to climb stairs.
As shown, this robot can only travel in a straight line, but this could be solved by adding a disc on the bottom of the inner foot to turn the robot when the outer feet are off the surface. Add some microswitch feelers and an Arduino, and it can autonomously explore your fridge without falling off. Maybe we’ll get around to building it ourselves, but be sure to drop us a tip if you beat us to it!
[gzumwalt] is a master of 3D printed devices like a rigid chain and a domino laying robot. The mechanism for this robot was inspired by one design from [thang010146]’s marvelous video library of mechanisms.
Looks like fun.
The freecad version is of course much better than that contraption in that mist based software.
Next step up is a rotating platform for the center piece so it can change direction.
A bit parallel to those big draglines from open pit mines.
Makes you wonder just what a stainless steel fridge is actually made from.
Put it outside under rain for a few days all you will know!
There is magnetic stainless steel, like the common 304 type. Its used a lot in kitchen and marine environment. 316 is less magnetic but for harsher environments.
Google Ferritic stainless steels and austenitic stainless steel.
Common misconception is “the less magnetic the more stainless”. I have ultra sonic tanks at work that are not magnetic at all and are rusting on outer side. And I have magnet bar for holding knives in my kitchen and non of them is rusty. For example Victorinox uses stainless for their blades and I havent seen a single one that is rusty (also havent seen them is salt water for 3 days so maybe should give them a chance?) but they are atracted by magnets.
I like the determination with which it climb.
This guy has made so many great motorized creations.