3 ms·
There's a video of it on the linked media piece https://www.nature.com/articles/d41586-022-01196-y https://www.nature.com/articles/d41586-022-01196-y It's got
by carapace 5y ago
There's a video of it on the linked media piece https://www.nature.com/articles/d41586-022-01196-y https://www.nature.com/articles/d41586-022-01196-y It's got four legs bowed like archery bows with radial tendons attached to the bellies of the curved legs and joined in the center, where a line goes vertically from the "feet" of the legs (which are bound together) to the main body of the device (acting as the string of all four bows.) It looks like a four-legged spider doing something kinky with ropes, or perhaps like it's trying to sit on an invisible beach ball (but the line and tendons are in the interior space.) Anyway, when the center line releases the legs straighten out and the whole thing launches into the air like a spring-powered model rocket.
It seems that the tendons are the bit that's adding extra stored energy to the jump, as the abstract mentions, "...the jump height of an engineered device can be far greater because its ratcheted or rotary motor can ‘multiply work’ during repeated strokes or rotations." I'm guessing that the "ratchet" is tightening the tendons, winding up the "oomph" before letting it go all at once. (On second thought, the ratchet mechanism must be in the body of the robot, so it's when its reeling in the line that the work of a small motor gets "multiplied" and stored in the legs/tendons/line.)
This reminds me of the toy pneumatic rockets that you pump up with a little hand pump and launch. Very similar principle, eh?
- smegsicle 5y agopneumatic rockets that eject water? those are very cool, in case anyone is looking for a summer gift for a kid who likes rockets
- carapace 5y agoYeah, they're a lot of fun! (And relatively safe: you might get hit in the eye but you won't get burned or start a fire.) You need the water for reaction mass, but water isn't compressible so you need air too to have something to pressurize to store energy. https://en.wikipedia.org/wiki/Water_rocket https://en.wikipedia.org/wiki/Water_rocket My favorite toy rocket is the venerable Matchstick Rocket. You lay a pin alongside a match with the tip of the pin against the head of the match, and then wrap the top half of both in a scrap of aluminum foil. Remove the pin, leaving a hollow nozzle for the gasses to escape. Perch the rocket on a bent-paperclip launch cradle and hold another lit match under the foil-wrapped head to ignite the solid fuel and initiate liftoff. They'll fly a meter or two, once you get the kinks out of the manufacturing process. Ooo! NASA has a page on making them: https://www.grc.nasa.gov/WWW/k-12/TRC/Rockets/match_rocket.html https://www.grc.nasa.gov/WWW/k-12/TRC/Rockets/match_rocket.h...
- TheJoeMan 5y agoAs a child my dad and I made a PVC launcher with a quick-release string. Turns out 100% launch success is a little less exciting.
- trhway 5y agoIt seems that there may be some way to improve [cross]bows here.