Pushing 3D Printed Wheels And Transmissions To The Limit

What do you do if you want a robot with great mobility? Walking is hard, and wheels are good enough, especially if you use the ‘wheels within wheels’ Mecanum setup. But you need torque, too. That’s what makes this entry into the Hackaday Prize so fantastic. It’s a Mecanum wheel of sorts, with an integrated gear set that produces a phenomenal amount of torque using a small, cheap stepper motor.

The wheel itself if 3D printed and fully parametric, using nylon weed wacker filament for the treads. This allows the wheel to scoot back and forth like a Mecanum wheel, or at the very least like one of those hyper mobile wheeled robots you see from time to time. It goes backwards, forwards, and side to side, and also has a zero turn radius.

A 3D printed Mecanum wheel is great, but how on earth do you drive it? That problem is solved with this hybrid planetary/strain-wave  3D-printed gear set. [Daren] has created a very compact ‘single’ stage gear set that fits right on top of a stepper motor. It’s thin, flat, and has a gear reduction of about 66:1. That’s a lot of torque in a very small package. Both of these projects are combined, and together they represent a freaky wheel with a lot of torque.

Even though [Daren] doesn’t have a robot in mind for this build, these are most certainly the building blocks of a fantastic robot, and a great entry in the Hackaday Prize.

Continue reading “Pushing 3D Printed Wheels And Transmissions To The Limit”

Watch These Two Robots Cooperate On A 3D Print

Putting a 3D printer on a mobile robotic platform is one thing, but two robots co-cooperatively printing a large object together is even more impressive. AMBOTS posted the video on Twitter and we’ve embedded it below.

The robots sport omnidirectional wheels and SCARA format arms, and appear to interact with some kind of active tabletop to aid positioning. The AMBOTS website suggests that the same ideas could be used for other tasks such as pick and place style assembly work, and the video below of co-operative 3D printing is certainly a neat proof of concept.

As a side note: most omni wheels we see (such as the ones on these robots) are of the Mecanum design but there are other designs out there you may not have heard of, such as the Liddiard omnidirectional wheel.

Continue reading “Watch These Two Robots Cooperate On A 3D Print”

Omni Wheels Move This CNC Plotter

We’ve always had a soft spot for omni wheels and the bots that move around somewhat bumpily on them. Likewise, CNC pen plotters are always a welcome sight in our tip line. But a CNC plotter using omni wheels is new, and the results are surprisingly good.

Built from the bottom of a spring-form baking pan, [lingib]’s plotter is simplicity itself. Four steppers turn the omni wheels while a hobby servo raises and lowers the pen. The controller is an Uno with a Bluetooth module for smartphone control. Translating wheel rotations into X- and Y-axis motions was not exactly trivial, and the video below shows the results. Lines are a bit wobbly, and it’s clear that the plotter isn’t hitting the coordinates very precisely. But given the somewhat compliant nature of the omni wheels, we’re surprised [lingib] got results as good as these, and we applaud the effort.

[lingib] reports the most expensive part of this $100 build was the omni wheels themselves. We suppose laser-cut MDF omni wheels could reduce the price, or even Mecanum wheels from bent metal and wood. We’re not sure either will help with the precision, though.

Continue reading “Omni Wheels Move This CNC Plotter”

Laser-Cut Mecanum Wheel For The Budget Roboticist

For the budding roboticist, omniwheels might be the next step in design patterns from your everyday “getting-started” robot kits. These wheels consist of tiny rollers that sit on the perimeter of the wheel and enable the wheel to freely slide laterally. With independent motor control of each wheel, a platform can freely locomote sideways by sliding on the rollers. You might think: “a wheel made of wheels? That sounds pricey…”–and you’d be right! Fear not, though; the folks at [Incubhacker] in Belgium have you covered with a laser-cut design that’s one-click away from landing on your workbench.

For anyone who’s tried to reliably mate flat laser-cut parts at an angle, we can tell you it’s no easy feat. The design here triumphs as both simple and reliable. Not only do they solve this problem elegantly, they also manage to create a design that will bear the load of a robot chassis that will travel with it. Laser-cut designs also usually suffer from a poor range of material options. Here the actual rollers need a bit more grip than what the plywood can provide. They also solve this problem effectively as well too, relying on heat-shrink tubing to provide the traction expected from a conventional wheel.

In the video below, [Incubhacker] takes you through the step-by process of making your own come to life. We’ve certainly seen some impressive laser-cut omniwheels in the past, but we like the simplicity of design combined with the composition of parts that probably already live on our workbenches.

Continue reading “Laser-Cut Mecanum Wheel For The Budget Roboticist”

Scrap Wood And Metal Combined For DIY Mecanum Wheels

Some scrap wood, a few pieces of sheet metal, a quartet of old gear motors, and a few basic hand tools. That’s all it takes to build an omni-bot with Mecanum wheels, if you’ve got a little know-how too.

For the uninitiated, Mecanum wheels can rotate in any direction thanks to a series of tapered rollers around the circumference that are canted 45° relative to the main axle.  [Navin Khambhala]’s approach to Mecanum wheel construction is decidedly low tech and very labor intensive, but results in working wheels and a pretty agile bot. The supports for the rollers are cut from sheet steel and bent manually to hold the wooden rollers, each cut with a hole saw and tapered to a barrel shape on a makeshift lathe. Each wheel is connected directly to a gear motor shaft, and everything is mounted to a sheet steel chassis. The controls are as rudimentary as the construction methods, but the video below shows what a Mecanum-wheeled bot can do.

There’s a lot of room here for improvement, but mainly in the manufacturing methods. The entire wheel could be 3D printed, for instance, or even laser cut from MDF with a few design changes. But [Navin] scores a win for making a working wheel and a working bot from almost nothing.

Continue reading “Scrap Wood And Metal Combined For DIY Mecanum Wheels”

The Auto Parking Mecanum Robot

mecanum

A while back, Hackaday visited the Clark Magnet School in Glendale, California to sneak a peek on their STEM-focused curriculum, FIRST robotics club, awesome A/V classroom, and a shop that puts most hackerspaces to shame. We saw a few builds while we were there, but [Jack]’s auto parking mecanum robot was in a class by itself. It deserves its own Hackaday post, and now that [Jack] is on Hackaday Projects, he’s sharing all the details.

The most impressive aspect of [Jack]’s build is the mecanum wheels; the side plates for the wheels were designed by [Jack] himself and machined on his school’s Haas mill. When the plates came out of the mill they were flat, and each of the fifteen little tabs on the plates needed to be bent at a 45 degree angle. With a CNC jig and a lot of time on his hands, [Jack] bent the tabs for all eight plates.

In addition to the plates, the rollers were custom made from non-expandable polyurethane poured into a CNC milled mold. That’s a one-part mold; [Jack] needed to make sixty of these little parts, one at a time.

The electronics are built around an Arduino Mega communicating with a joystick via an XBee. [Jack] found the relays in the off-the-shelf motor board couldn’t handle the current, so he replaced them with much, much larger ones in a hack job we’d be proud to call our own handiwork. There’s also a little bit of code that allows this motorized cart to pull off the best parallel parking job anyone could ever wish for. You can see that and a few videos of the construction below.

Continue reading “The Auto Parking Mecanum Robot”

Robot Bicep Curl Accompanied By Too Much Fanfare

So this is the world’s strongest robot arm. Great… no really, that’s wonderful. We think lifting a 1000 kilogram dumbbell is a good way to show it off to the public. But with great power came the world’s most over-the top marketing. Well, maybe not as bad as the shake weight but it’s getting there. In the video after the break you’ll see that there is plenty of adrenaline-pumping music and they’ve hired an acrobat to pull a sheet off of the thing. We’ve pointed her out in the image above. [Caleb] noticed that they seem to have programmed in human kinetic to make it bounce and strain as a human lifting a heavy load would. And then there’s the fog machine. Classic. We also enjoy the use of a tap light (which we’ve seen around here before) to activate the demo.

But now we’re getting carried away. The article linked at the top covers a new development for the arm; a motorized base that can move it around. Looks like the base, which uses mecanum wheels, just slips under a stationary frame for the robot and lifts enough to truck it around.

Continue reading “Robot Bicep Curl Accompanied By Too Much Fanfare”