For all its ability to advance modern society in basically every appreciable way, science still has yet to explain some seemingly basic concepts. One thing that still has a few holes in our understanding is the method by which a bicycle works. Surely, we know enough to build functional bicycles, but like gravity’s inclusion into the standard model we have yet to figure out a set of equations that govern all bicycles in the universe. To push our understanding of bicycles further, however, some are performing experiments like this self-balancing omniwheel bicycle robot.
Functional steering is important to get the bicycle going in the right direction, but it’s also critical for keeping the bike upright. This is where [James Bruton] is putting the omniwheel to the test. By placing it at the front of the bike, oriented perpendicularly to the direction of travel, he can both steer the bicycle robot and keep it balanced. This does take the computational efforts of an Arduino Mega paired with an inertial measurement unit but at the end [James] has a functional bicycle robot that he can use to experiment with the effects of different steering methods on bicycles.
While he doesn’t have a working omniwheel bicycle for a human yet, we at least hope that the build is an important step on the way to [James] or anyone else building a real bike with an omniwheel at the front. Hopefully this becomes a reality soon, but in the meantime we’ll have to be content with bicycles with normal wheels that can balance and drive themselves.
Sure, there are smart canes out there, commercial and otherwise. We’ve seen more than a few over the years. But a group of students at Stanford University have managed to bring something novel to the augmented cane.
Another day, another Kickstarter. While we aren’t often keen on touting products, we are keen on seeing robotics and unusual mechanisms put to use. The Goliath CNC has long since surpassed its $90,000 goal in an effort to put routing robots in workshops everywhere.
Due to their cost and complexity, you often only find omni-wheels on robots scurrying around universities or the benches of robotics hobbyists, but the Goliath makes use of nine wheels configured as three sets in a triangular pattern. This is important as any CNC needs to make compound paths, and for wheeled robots an omni-wheel base is often the best bet for compound 2D translation.
What really caught our eye is the Goliath’s unique positioning system. While most CNC machines have the luxury of end-stops or servomotors capable of precise positional control, the Goliath has two “base sensors” that are tethered to the top of the machine and mounted to the edge of the workpiece. Each sensor connects to the host computer via USB and uses vaguely termed “Radio Frequency technology” that provides a 100Hz update for the machine’s coordinate system. This setup is sure to beat out dead-reckoning for positional awareness, but details are scant on how it precisely operates. We’d love to know more if you’ve used a similar setup for local positioning as this is still a daunting task for indoor robots.
A re-skinned DeWalt 611 router makes for the core of the robot, which is a common option for many a desktop milling machine and other bizarre, mobile CNCs like the Shaper Origin. While we’re certain that traditional computer controlled routers and proper machining centers are here to stay, we certainly wouldn’t mind if the future of digital manufacturing had a few more compact options like these.
[Jochen Alt]’s Paul is one of the coolest robots of its type, and maybe one of the coolest robots period. Personality? Check. Omniwheels? Check. Gratuitous feats of derring-do? Check. Paul is a ball balancing robot.
Under the hood, Paul isn’t all that strange. He’s got two microcontrollers, one for taking care of the balancing and kinematics, and another that handles the LEDs, speech processor, loudspeaker, remote-control, and other frilly bits. But the mathematics! Paul is a cylinder standing up on top of a bowling ball, so the only way it can roll forwards is to lean forwards. But of course, it can’t lean too much, because it has also got to balance. It’s absolutely the least reasonable means of locomotion. We love it.
[Jochen] was nice enough to put everything up on GitHub, so you can see how it was done, even though it looks like magic. And we dare you to watch the video, embedded below, and not feel at least a pang of sympathy pain when (spoiler alert!) he falls flat on his face. Does he recover? We’d love to know!
Omnidirectional wheels are one of the hardy perennials of the world of invention. There seems to be something about the prospect of effortless parallel parking that sets the creative juices of backyard inventors flowing, and the result over the years have been a succession of impressively engineered ways to move a car sideways.
The latest one to come our way is courtesy of Canadian inventor [William Liddiard], and it is worthy of a second look because it does not come with some of the mechanical complexity associated with other omnidirectional wheel designs. [Liddiard]’s design uses a one-piece tyre in the form of a flexible torus with a set of rollers inside it which sits on a wheel fitted with a set of motorised rollers around its circumference. The entire tyre can be rotated round its toroidal axis, resulting in a tread which can move sideways with respect to the wheel.
The entire process is demonstrated in a video which is shown below the break, and the small Toyota used as a demonstration vehicle can move sideways and spin with ease. We would be wary of using these wheels on a road car until they can be demonstrated to match a traditional tyre in terms of sideways stability when they are not in their omnidirectional mode, but we can instantly see that they would be a significant help to operators of industrial machines such as forklifts in confined spaces.
What’s better than a caster? An omniwheel. These wheels are like a big wheel with little wheels at different angles that can roll in any direction. [Sonodera] built an omniwheel out of laser cut MDF. MDF–or Medium Density Fiberboard–makes up all the parts of the wheel. There’s no plastic or metal at all.
[Sonodera’s] wheel is more of a passive design like a caster. It would be possible to drive the wheel through the center in two directions, but the right-angle rollers are passive.
We’ve seen several robots with omniwheels before. In fact, this tripod-inspired robot also has passive rollers and the three-legged design takes advantage of them (the so-called Kiwi drive). Some schemes combine multi-directional wheels with conventional wheels (usually the standard wheels are in the center). There are other multi-directional wheel designs out there, including the Mecanum wheel. You can see a video of the MDF wheel in action, below.
The omniwheels work in this tripod orientation because they include rollers which turn perpendicular to the wheel’s axis. This avoids the differential issue cause by fixed-position wheels. When the three motors are driven correctly, as shown in the video below, this design makes for the most maneuverable of wheeled robots.
An aluminum plate serves as the chassis. [Malte] milled the plate, cutting out slots for the motor with threaded holes to receive the mounting screws. A few stand-offs hold the hunk of protoboard which makes up the electronic side of the build. The large DIP chip is an ATmega168. It drives the motors via the trio of red stepper motor driver boards which he picked up on eBay.
So far the vehicle is tethered, using a knock-off of a SixAxis style controller. But as we said before, driving the motors correctly is the hard part and he’s definitely solved that problem.