MIT student unicycles, Segway-style
Homebrew ‘leccy single-wheeler
A student at MIT has created a nearly self-balancing electric unicycle, imitating the kind of stability control seen in the Segway.
Demonstrated in a YouTube video, the “Bullet” unicycle, created by MIT student Stephan Boyer, can’t manage to be self-balancing sideways, but does protect the rider from falling over in the forwards or backwards direction.
Boyer claims a five-mile (eight kilometer) range for his little ‘leccy luggable transport, and says it can reach speeds up to 15 miles per hour (about 24 km/h).
He also says that his design and choice of components meant that the Bullet only cost him “several hundred dollars” to build, rather than thousands. If other enthusiasts want to make a similar attempt, Boyer has published the kit-list http://www.stephanboyer.com/p/self-balancing-electric-unicycle.html here. He’s also published the software for the unicycle.
While cool, El Reg can’t imagine that even a production version of the Bullet would ever replace some Segway applications. Even riders of the original two-wheel version can come a cropper if they’re not paying attention: just ask the Segway-riding cameraman whose exploits at an Australia-India cricket test are shown below. ®
A robot that balances on a ball wont work you say, I guess i just imagined this http://www.ted.com/talks/peter_fankhauser_meet_rezero_the_dancing_ballbot.html
..and go crab-style
The way a uni balances sideways is via torso twist, which changes wheel rolling direction, allowing the contact patch to be translated side to side (while the wheel is turning, anyway). Actual turning is difficult because total angular momentum must be added in one direction and then removed, using only a tiny friction patch in contact with the ground. The turn is achieved via a combination of friction and "carving." It's a bit hard to describe, but the rubber tread must do some scraping during each turn, which is actually audible if you listen closely.
A ball-wheel that can be driven in any direction is great, the payolad can stay balanced, but true turning becomes nearly impossibe due to the large friction patch preventing any actual angular change. Making the ball low-friction doesn't help because the turn-carving action depends on the wheel's shape to work, which won't be present on a radially symetric ball.
The result is that you can easily go any direction, but you can only face one way. Hmmm, sounds kinda cool, actually...
Well! If you insist on
running over helmets and sundry other road hazards, nothing will protect you.