Tuesday, October 28, 2014

Omniwheel Prototype 2

I made a second prototype for the omniwheel. The point was to test out a few things:
The knurled shaft on these smaller set of motors is pretty long, so I made the gear the full length of that. That helps keep the fit straight. I will be increasing the channel length of the other press fit gears I print from now on, so that getting them straight isn't a matter of skill with the mallet or arbor press.

The 'tires' are made from inside-outed waterproof heat shrink. The inside is tackier, but you can only inside-out small pieces at a time. The adherence isn't great unless you get the plastic just melty enough to conform to the tire without collapsing/deforming. You have to hand carve away the excess. Not a good method. I've ordered some 'silicone heat shrink' on eBay that will arrive in November; hopefully that product is different than this one. This could work great for beads with larger surface area if it came with the tacky side out.

Previously I had tried Rustoleum Flexible Rubber, but the droplets were far too big and the whole thing ended up being a globby mess. FlexiDip sprayed on nicer with a fine droplet mist but it wasn't all that rubbery. Plastidip seemed similar but a little thinner (more solvent per less payload) but this needs more testing.

Here's a picture of my second desk. HobbyKing batteries arrived today and actually seem like a good fit and weight for my cart robot design. I've already redesigned the cart gearing system, so all that remains to be done for the cart live demo is to figure out a the small gear press fit going on sideways problem, and to resize and refine the motor mounts.

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