Multirotor aircraft enjoy many intrinsic advantages, but as machines that fight gravity with brute force, energy efficiency is not considered among them. In the interest of stretching range, several air-ground hybrid designs have been explored. Flying cars, basically, to run on the ground when it isn’t strictly necessary to be airborne. But they all share the same challenge: components that make a car work well on the ground are range-sapping dead weight while in the air. [Youming Qin et al.] explored cutting that dead weight as much as possible and came up with Hybrid Aerial-Ground Locomotion with a Single Passive Wheel.
As the paper’s title made clear, they went full minimalist with this design. Gone are the driveshaft, brakes, steering, even other wheels. All that remained is a single unpowered wheel bolted to the bottom of their dual-rotor flying machine. Minimizing the impact on flight characteristics is great, but how would that work on the ground? As a tradeoff, these rotors have to keep spinning even while in “ground mode”. They are responsible for keeping the machine upright, and they also have to handle tasks like steering. These and other control algorithm problems had to be sorted out before evaluating whether such a compromised ground vehicle is worth the trouble.
Happily, the result is a resounding “yes”. Even though the rotors have to continue running to do different jobs while on the ground, that was still far less effort than hovering in the air. Power consumption measurements indicate savings of up to 77%, and there are a lot of potential venues for tuning still awaiting future exploration. Among them is to better understand interaction with ground effect, which is something we’ve seen enable novel designs. This isn’t exactly the flying car we were promised, but its development will still be interesting to watch among all the other neat ideas under development to keep multirotors in the air longer.
[IROS 2020 Presentation video (duration 10:49) requires no-cost registration, available until at least Nov. 25th 2020. Forty-two second summary embedded below]
Continue reading “One Wheel Is All We Need To Roll Into Better Multirotor Efficiency”
[XenonJohn] wrote in to let us know about updates and a recent test drive of an Electric Self-Balancing One-wheeled Motorcycle, fresh from the beach where he says it proved to be great fun to ride. The design and build have been updated since we last saw it as a semifinalist entry in the 2014 Hackaday Prize. The original, he says, “looked cool but was slow, cumbersome and really dangerous to ride.”
Since then it has been completely redesigned and now has a super fat kite-surfer wheel, a front crash skid with damper, and a variable geometry which allows it to steer properly despite just having one wheel. It does this by allowing the rider to shift their position relative to the wheel, instead of the seat always being rigidly locked directly above the axle.
That steering is a pretty clever upgrade, but we do wonder if the new crash skid will have an atlatl effect and really launch the rider in a crash. Our gut feeling aside, it is designed not to plant itself in the pavement, but to slide along (without ejecting the rider) until the vehicle loses all momentum.
There is something about self-balancing unicycles that attracts experimenters, each of whom takes a different approach. We see everything from this device constructed mainly from a Razor Scooter to this more polished-looking unit based on an earlier Segway clone design. [XenonJohn] reminds us that “there is still much to learn in this area and you can genuinely innovate even as a hobbyist. Also, you can only do so much on a computer, you then have to actually build something and see how well it works. [This recent test] shows what you can do if you just keep on experimenting.” Video of the test drive is below.
Continue reading “Self-Balancing One-Wheel Motorcycle Tears Up The Beach”
Throughout time it’s just been plain cool to genie around from point A to B on some form of personal portable hardware. Understandably so, it was the goal of [Dane Kouttron] to modify and improve the common standard in such a way that anyone could hop on his board and ride without a period of flailing to keep balance. In his Flying Nimbus project, the rider floats aloft a single power-driven wheel that will even do the balancing bit for you.
Inspired by some interesting aluminum scraps and an old 3 phase DC servo driver, [Dane] starting conjuring ideas of combining the two in order to produce his own self balancing form of transportation. A chunky reused tire from a local go-kart track turned out to serve as his wheel of choice which would mount between the feet of the rider. After ordering a 48v hub motor and waiting for it to make its way over from China, [Dane] took the time to model all of the individual parts, motor, and wheel in CAD to figure out the needed measurements for the custom pieces he’d later fabricate to fit around them. The aluminum frame that the rider stands upon not only houses and conceals the power cells and electronics running the central wheel, it also illuminates white light from the sides to stand out at night. Along the road of troubleshooting, [Dane] eventually scored a complementary top-notch servo drive from AMC, who ultimately wanted to see his project rolling as badly as he did. There is a load of detailed documentation on the layers of problem solving that went into the project on his blog, as well as more on the hardware used by [Dane] to get the board actively balancing. Seeing the final product should further enforce that there is no better way to get around then on the likes of something you made yourself:
Continue reading “Surfing Around On A Self-Balancing Cloud”