Freakishly Agile Crawler Rocks All-LEGO Mechanum Wheels

Mechanum wheels are great, but you have to have them perfectly alined or they come across a little clunky, giving your robot a herky-jerky movement. Robotics educator and supreme LEGO builder [Yoshihito Isogawa] built a mechanum-wheeled rover that has the angles right: each wheel consists of 12 smaller rubber tires angled at 45 degrees. The key to the project is Part Number 85940, accurately if unsexily named “double Ø4.85 hole w/ Ø3.2 shaft”. It consists of a double technic hole with a shaft projecting in a 45-degree angle.

Unlike his omni-roller project with 3 large wheels and the mechanum tank treads he built for another project, this one features the gold standard of mechanum movement: creepy agility. He also did a version with 9 side rollers per wheel, and it was nearly as stable.

Hackaday loves [Yoshihito]’s great creations, which are as beautiful and elegant as they are functional. His all-LEGO centrifugal pump and his spirograph machine make expert use of parts to make the builds as simple as possible.

9 thoughts on “Freakishly Agile Crawler Rocks All-LEGO Mechanum Wheels

    1. They work best on a grippy floor. In a conventional tire contacting the ground there are 3 degrees of freedom that are constrained = one is fore-aft which has it’s motion controlled by torque (if any) supplied by the axle. The second is side-to-side and the third is twist.

      This eliminates one degree of freedom by adding the no-torque resistance peripheral axles, which is why it can also go sideways, so it has no greater problem with high-traction surfaces than a conventional tire. I think these wheels have lower traction because of that additional degree of freedom.

  1. Heh… last time I tried doing that, I did so by rotating each entire wheel.

    I’ll point out though the vehicle in question was a harvester (about the size of a typical bus) with 20kW motors (@48V… so 400A) in each hub. We would have had it working too if the MOSFETs driving the steering motors didn’t keep blowing up. I might have some video of it going… was looking around for a video of the prototype that was done ~2007-2008. Google Search for “SmartWheel” (the now defunct company that did it) doesn’t give me any joy… seems someone else is using that name for a different product now.

    Not sure if this method would scale to a wheel that stands about 1.5m tall, but I admire the agility of this model.

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