pic: Too much power?

[AllenGregoryIV]

Originally Posted by Chris is me

Just out of curiosity, what are each of your wheels geared for? I'm curious as to what kinds of current you're drawing when the wheels slip in each orientation, and I can estimate that from the drive free speed. I've been trying to figure out of the old 4 CIM rule of thumb for low gears ("traction limited at 40 amps") isn't conservative enough for 6+ motor drives, and I could use some data.

There are some more circumstances that play into this as well. Namely each wheel is independent so we lose some power in pushing matches when wheels lift off the ground.

The complete drive train is setup like this.

2 CIMs on each rear wheel module. 1 CIM and 1 MiniCIM on each front wheel module.

Each module is geared 12:72 for the omni wheel using VexPRO gears and then there is a 2nd reduction to the traction wheel that is 18:42 with VexPRO pulleys and 9mm wide belt. So overall we are 6:1 and 14:1 in the two different ratios. 4 in wheels in both omni and traction. I would like to be 5:1 in high gear but at that point I think we would could stall the main breaker but it's something we will probably try.

Our current setup has the traction wheels on the inside of the modules and the omni wheels towards the front and back of the robot and we pivot the traction wheels up and down. This provides us with less scrub when we are on the traction wheels but hurts us in pushing matches because we can easily be lifted off our front wheels and engage the omni wheels and traction wheels on the back side which is clearly not ideal. The next iteration will attempt to use smaller traction wheels that are at the front and back of the robot. We will likely continue to fix the omni wheel and pivot the traction wheels so we don't have to float our motors on the module.