Rolling Out A New Robot Arm

A lot of great scientific breakthroughs come through imitating nature, but technology often runs up against limits in certain areas. This is particularly evident in robotics, where it takes a lot of effort (and cost) to build a robot which can effectively manipulate heavy objects but not crush others which are more delicate. For that, a research group has looked outside of nature, developing a robotic grasper which uses omnidirectional wheels to grab various objects.

The robot hand is composed of three articulating fingers with fingertips which are able to actively manipulate the object that the hand is holding. With static fingertips, it is difficult to manipulate an object in the hand itself, but with the active surfaces at the fingertips it becomes easier to rotate the object without setting it down first or dropping it.

The project is much more than designing the robot hand itself, too. The robot uses calculated kinematics to manipulate the objects as well, but a second mode was also tried where the robot was able to “learn” how to handle the object it was given. The video linked below shows both modes in operation, with interesting results. If you prefer more biologically-inspired robot arms, though, there are always novel designs based on non-humans.

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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.

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Step The Halbach From My Magnets

[Klaus Halbach] gets his name attached to these clever arrangements of permanent magnets but the effect was discovered by [John C. Mallinson]. Mallinson array sounds good too, but what’s in a name? A Halbach array consists of permanent magnets with their poles rotated relative to each other. Depending on how they’re rotated, you can create some useful patterns in the overall magnetic field.

Over at the K&J Magnetics blog, they dig into the effects and power of these arrays in the linear form and the circular form. The Halbach effect may not be a common topic over dinner, but the arrays are appearing in some of the best tech including maglev trains, hoverboards (that don’t ride on rubber wheels), and the particle accelerators they were designed for.

Once aligned, these arrays sculpt a magnetic field. The field can be one-sided, neutralized at one point, and metal filings are used to demonstrate the shape of these fields in a quick video. In the video after the break, a powerful magnetic field is built but when a rare earth magnet is placed in the center, rather than blasting into one of the nearby magnets, it wobbles lazily.

Be careful when working with powerful magnets, they can pinch and crush, but go ahead and build your own levitating flyer or if you came for hoverboards, check out this hoverboard built with gardening tools.


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Harrier-like Tilt Thrust In Multirotor Aircraft

A traditional quadcopter is designed to achieve 6 degrees of freedom — three translational and three rotational — and piloting these manually can prove to be a challenge for beginners. Hexacopters offer better stability and flight speed at a higher price but the flight controller gets a bit more complex.

Taking this to a whole new level, the teams at the Swiss Federal Institute of Technology (ETH Zürich) and Zurich University of the Arts (ZHDK) have come together to present a hexacopter with 6 individually tiltable axes. The 360-degree tilt in rotors allows for a whopping 12-degrees of freedom in flight and allows the UAV to fly in essentially any direction including parallel to walls.

In addition to the acrobatic capabilities of the design, the team has done some testing with autonomous control using external cameras. Their blog contains videos of their testing at various stages and it interesting to see the project evolve over a short span of nine months. Check out the video below of the prototype in action.

With Amazon delivering packages via drone and getting patents for parachute labels, UAV design is evolving faster now than ever. We can’t wait to see where this 12 DOF takes the state of the art. Continue reading “Harrier-like Tilt Thrust In Multirotor Aircraft”

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.

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Robomintoner Badminton Bot To Defeat Amateur Humans

Watching robots doing sports is pretty impressive from a technical viewpoint, although we secretly smile when we compare these robots’ humble attempts to our own motoric skills. Now, a new robot named Robomintoner seeks to challenge human players, and it’s already darn good at badminton.

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Homemade Omnidirectional Speakers In A Unique Enclosure

While studying acoustics in college (university for non-Americans), [Nick] had a great idea for an omnidirectional speaker. Some models available for purchase have a single speaker with a channel to route the sound in all directions, but [Nick] decided that a dodecahedron enclosure with 12 speakers would be a much more impressive route.

To accommodate the array of speakers, the enclosure needs twelve pentagons with a 58.3 degree bevel so that they fit together in a ball shape. After thinking about all of the complicated ways he could get this angle cut into the wood pentagons, he ended up using a simple circular saw!

Once the enclosure was painted [Nick] started wiring up the speakers. The equivalent impedance of the array of 8-ohm speakers works out to just around 10 ohms, which is easily driven by most amplifiers. The whole thing was hung from a custom-made galvanized pipe (all the weight adds up to about 15 kilograms, or 33 pounds for Americans, so the rig needed to be sturdy). We’ve featured other unique speaker builds, but this is the first 12-speaker omnidirectional speaker we’ve seen. [Nick] is happy to report that the speakers sound great, too!