Quote:
Originally Posted by RobotsThatWork
You mean the strafing module, right?
We took inspiration from 148's strafing module (from their 2014 robot, Vader). The module itself spins on the axle that's powered by the CIM. So when the CIM is powered, the module spins down until a wheel contacts the wheel. The CIM will exert enough force to push down the module enough to have the ground exert a normal force on the wheel (which is what traction is dependent on) before the torque of the CIM spins the omniwheel.
At least that's how I understood it while designing this. We haven't actually done more serious math outside of a simple free body diagram. If someone from 148 or anyone with experience with this type of strafing module could explain more/clarify/prove me wrong, that would be awesome.
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Yep. That's what I'm talking about. The diameter of the wheel, clearance from the ground when horizontal, and gearing all play a role in how much normal force the wheel can exert on the ground.
We struggled with tuning the amount of force our strafing modules needed in 2015, but that was going over the bump + with and without totes, so it had to move more weight / accelerate more mass than just a robot and that weight varied quite a bit.
I looked at 148's design when thinking about ours, but we had one shot at getting it right (we swapped our drive from mechanum to this at state champs) so I ended up going with 2 strafe modules, held down with gas shocks counter balanced by surgical tubing so we could adjust the downward force.
The 148 solution is lighter and more elegant, but more difficult to get right.