Hi! Our team has been working on our drivetrain and we decided to use 6 wheels, 2 omni-wheels in the front, 2 normal wheels in the middle, and 2 omni-wheels in the back.
But, we noticed that the normal wheels in the middle aren’t touching the ground. We realized that the normal wheels are slightly smaller than the omni-wheels.
So we were wondering if you guys had any ideas bout how we could increase the size of the normal wheels or other troubleshooting ideas. Thanks!
Any teams have had this problem due to omni wheels being slightly larger than traction wheels. A popular soulation is to make a custom traction wheel using a cut out flex wheels. Alternatively and more simply wrap a bunch of rubberbands until it is the right size. You can also look up “locked omnis” or “custom traction wheels” in the search bar.
If you install a high traction tire on a wheel with a rubber band between the wheel an tire, the assembly is large enough to have them contact the foam tiles.
Also note that omni wheels do sink into the foam a bit, more so with a full robot than just a drive base. Keep that in mind as you assess solutions to your center wheel issue.
In addition to this, you could also look at buying the new anti static Omni wheels as they are actually 4 inches instead of 4.125 inches.
As @EcstaticPilot said, you can lock omni-wheels and put them in the middle. This is done by using 3/8-inch screws and pushing them into each individual roller on the omni-wheel.
Omni-wheels provide extra traction, but the numerous screws involved in this process (48, I think for 2 wheels) can add a lot of unnecessary weight. Of course, you could also use rubber bands.
As has been previously stated, Locked Omnis are a good alternative to a 3rd traction wheel. However, when I first came across this idea, I did not quite understand. This video helped a lot explaining it, if it helps you, good to hear, otherwise someone might find it useful a couple years down the line.
Locked Omni Video