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!
Paul is just one of the stellar robots in the 2017 Hackaday Sci-Fi contest, so head on over there if you still don’t have your fill.
Continue reading “Paul: A Robot and its Ball”
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.
Continue reading “Liddiard Omnidirectional Wheels”
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.
Machinist, electronics engineer, programmer, and factory worker are all skills you can wield if you take on a project like building this omniwheel robot (translated).
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.
Continue reading “Omniwheel robot build uses a bit of everything”
For a number of children born of geek parents, the WowWee Tribot is sure to make an appearance underneath a Christmas tree this year. By New Year’s, though, this toy will surely make its way to the back of a closet to sit unused until spring cleaning. It’s a shame to let such an interesting robotics platform go to waste, so [haltux] sent in a nice guide to unlocking the motor controller of this talking robot.
The ‘legs’ of the WowWee Tribot have three omnidirectional wheels mounted 120 degrees apart. We’ve seen this drive system before, so getting a pre-built platform out of the toy box is pretty interesting.
[haltux] found three H-bridges inside the Tribot and connected the direction and enable pins for each motor directly to an Arduino. The build was a success, and the new robot platform scurried along the floor. There are also rotary encoders on the Tribot, but these run at 12 Volts. [haltux] said he’ll cover these in a future post, and we’re waiting to see it.
Like all of us, [Jonathan Guberman] has a list of projects and builds that ‘will get done when I have time.’ His Kiwi drive robot is no exception. It’s intended to be one piece of a much larger project, but he decided to document it anyway (we think in the hope of getting is rear in gear).
The robot uses a holonomic drive to get around. A holonomic drive uses three fixed wheels placed 120 degrees apart. The wheels can be independently controlled and with some vector addition the robot can move in any direction and rotate 360º inside its own wheelbase. Of course the wheels will have to be able to roll in two dimensions, so an omniwheel is used. Everything is controlled with a Wiimote nunchuck, and the movement is very smooth.
[Jonathan] has had a few projects featured on Hack A Day before, like his Mechanical Pac-Man and his adorable Portal turret plushie. [Jonathan] really demonstrates his artistry and skill in his project, so we’re really wondering what his ‘larger project’ actually is. Take a guess in the comments section, that might get [Jonathan]’s rear in gear.
Check out the video of the omnidirectional robot after the break.
Continue reading “Omniwheel robot”