Who Needs Mecanum Wheels?

April 3, 2012 by Mike Szczys 36 Comments

Skills are all that’s needed to solve a problem. Take this four-wheeled robot as an example. [Michal Zalewski] wanted it to be omnidirectional but wasn’t very satisfied with the concept of mecanum wheels and the like. So he designed a chassis with wheels at each corner that can pivot as one to change orientation. The image may look like a rendering at first glance, but this is actually the physical prototype. See what we mean about skills?

Okay, so the robot design is pretty cool. But we’re more excited about the build process. We’ve looked at [Michal’s] work before. He wrote a thorough guide about CNC mold making. These parts are all cast from epoxy. This starts with a rough milled mold, which is given a second pass for the fine details before being painted with a release agent and used to make a silicone mold. From this the parts are produced. Check out the Flickr set showing the casting process for the planetary gear box on each motor. If only these results were as easy to achieve as he makes it look.

[via Reddit]

Working Tachikoma Brings The Manga To Life

April 3, 2012 by Mike Szczys 19 Comments

This Lego Tachikoma drives and walks just like in the TV program. You simply must take a peek at the video after the break. We’ve watched it several times and don’t think there’s any editing magic going on. But the movements are so intriguing part of us thinks there’s something fishy about it.

Each leg has a wheel that is connected to a motor via chain drive. But the little guy isn’t constrained to smooth hard surfaces. When the going gets rough, he struts his stuff like an eight-year-old crossing the lawn in roller skates.

This is not just for show and you can build it yourself if you like. The link at the top has assembly instructions. You will need several specialized parts though, not the lest of which is the cement mixer drum halves that make up the rounded blue chassis pieces.

Not sure what the heck this thing is? Don’t feel bad, you’d need to be a fan of Ghost in the Shell to recognize it.

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Sphere Morphing Hexabot Now Rolls Around

April 2, 2012 by Brian Benchoff 43 Comments

[Zenta] has been building his MorpHex rolling hexapod for nearly a year now, and good things come to those who wait. After a ton of development and fabrication, [Zenta] finally has his mechanical jellyfish robot rolling and walking around.

This isn’t the first time we’ve seen [Zenta]‘s MorpHex robot in action. A year ago, we saw the beginnings of the project with that included 25 servos mounted on a custom chassis. Last winter, the top hemisphere of the MorpHex was added, but rolling locomotion was still on the drawing board. A lot has changed since then, and now [Zenta]’s robot can roll or walk across the floor.

From the video (available after the break), we see that [Zenta] kept the one degree of freedom for the panels on the upper cylinder. He’s thinking about making the MorpHex more symmetrical; just copying the plans for the bottom hemisphere onto the top, for instance. This plan would allow the MorpHex to roll in a straight line, so we can’t wait to see what [Zenta] cooks up next.

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Powering A Robot With A Macbook Battery

April 1, 2012 by Brian Benchoff 5 Comments

When [Soo-Hyun]’s friend had an Apple Macbook Pro battery that began to swell, his friend did the reasonable thing and donated it to be used in a robot. Now [Soo-Hyun]’s kiwi drive robot is powered by a gigantic LiPo battery, giving it a huge range and a very fast top speed.

The defunct laptop battery that formerly powered a 15″ macbook pro is three battery packs of two cells in parallel, delivering 12.6 Volts. To get the power to the robot, [Soo-Hyun] etched a simple PCB that fit into the slot in the battery. A little bit of soldering later, and mounting the battery as a shark fin because of the 8×8 inch limitation of maze-solving robots, the power plant was complete.

Using a bulging LiPo battery probably isn’t the smartest idea (listen for the great line, “it got the camera and my face” at 4:08), but as long as [Soo-Hyun] keeps an eye on the battery as it’s charging, it should be alright.

Check out the video of the robot zipping around on 12.6 Volts after the break.

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Sand Flea Literally Leaps Tall Buildings In A Single Bound

March 31, 2012 by Mike Szczys 38 Comments

The hidden abilities of this robot that is no larger than a dinner plate are quite impressive. It doesn’t let an obstacle like a building get in its way. The Sand Flea, like its namesake, posses a remarkable jumping ability. When it encounters a tall obstruction two levers incline the front of the robot and it launches itself up to thirty feet in the air. In the case of a one-story build this means it will end up on the roof, and it’ll do so much quicker and more reliably than any wall climber we’ve seen.

It’s being developed for the US Army by Boston Dynamics, and this isn’t the first time we’ve seen the concept. But the video after the break gives a much better look than the grainy twenty-second clip from last year. Of course they’re not giving up too many details so we have to guess a bit. We’d wager the launching mechanism is a solenoid, but at about eleven pounds you need a lot of juice to get that much of a jump. We suppose it’s also possible that there’s an explosive system like the butane combustion used in a framing nailer. The video summary mentions that there’s a stabilization system to keep the body oriented during flight. That’s got to be a gyroscope. Let us know what you think in the comments. Continue reading “Sand Flea Literally Leaps Tall Buildings In A Single Bound” →

Loudest Telepresence Robot Ever

March 30, 2012 by Mike Szczys 9 Comments

This telepresence robot will never let your Skype callers sneak up on you. [Priit] built the project, which he calls Skype Got Legs, so that his distant friends could follow him around the house during chats. But as you can hear after the break, the electric drills used to motorize the base are extremely loud.

Noise pollution aside, we like the roughness of the hack. It’s utilitarian but seems to work quite well. Commands are sent via the web using a combination of Ajax and PHP function calls. The two drills are controlled by an Arduino via a couple of automotive relays. The drills are powered by their original rechargeable battery packs. So as not to alter those batteries, [Priit] figured out a way to use synthetic wine bottle corks as a connector. They’ve been cut to size, and had tinned wires pushed through holes in them. Now, when he inserts the altered corks they press the wires against the battery contacts. Continue reading “Loudest Telepresence Robot Ever” →

Self-stabilizing Autonomous Bicycle

March 25, 2012 by Brian Benchoff 52 Comments

For [Gunnar]’s diploma thesis, he wanted to build an autonomous bicycle. There’s an obvious problem with this idea, though: how, exactly does a robotic bicycle stand upright? His solution to balancing the bicycle was a reaction wheel that keeps the bicycle upright at all times.

A bicycle is basically an inverted pendulum; something we’ve seen controlled in a number of projects. To balance his driver-less bike, [Gunnar] used a stabilizing wheel and an IMU to make sure the bicycle is always in the upright position. The bike measure the tilt and angular velocity of itself, along with the speed of the stabilizing wheel. To correct a tilt to the left, the stabilizing wheel spins clockwise, and corrects a rightward tilt by spinning counterclockwise.

While [Gunnar]’s solution of a bike wheel used as a gyroscope is clever – it uses common bicycle wheel, hugely reducing costs if someone wants to replicate this project – there’s not a whole lot of ground clearance. The size of the stabilizing wheel could probably be reduced by replacing the 7.4 kg steel wheel with a Tungsten, Osmium, or Lead disk, possibly becoming so small it could fit inside the frame. Still, though, a very nice build that is sure to turn a few heads.

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