[magnets]

Neat idea. However, I am fairly certain that your worm wheel will loose teeth when you have the weight of the robot behind it. If your robot is going fast, and suddenly you stop applying power, the worm wheel won't be to turn the worm gear, so you'll just snap a tooth off. It will be different than just testing it on a table.

In the video you talked about having to use a smaller worm wheel in order to get the same reduction. These are pretty fragile, so you could switch to a bigger worm wheel with a two-start worm.

A few other recommendations. Be sure to lubricate your gears! Make sure there isn't any play sliding the worm or worm wheel up and down on their shafts and that the unsupported drive axle doesn't wiggle around, but a little play in rotating the gears (like you showed in the video) is really important. That backlash makes the transmission operate more smoothly, and helps with lubrication, especially when you're using gear like this, than "slide" instead of "roll" on each other.