pic: Drivetrain Prototype

[Chris is me]

Originally Posted by Mop Iii Top

Hold the phone here. Why are you using 4 CIMs? I can see using 4 CIMs for Mecanum wheel, besides you have to use 1 CIM per mecanum wheel. This years limit on CIM Motors was only 5. You are using up most of them and not leaving yourself more for other things. If you used only 2 CIM Motors, one for each side, you would give yourself 3 CIM Motors to play around with on the rest of the robot.

Using a drivetrain with less than 4 CIMs in FRC is something that should be approached carefully (I'm trying to get as close to saying "never" as possible without saying it). If you don't shift, I would only use it in the extremely rare case that your drivetrain is only used for a short while in a match, like 125's robot this year which cannot function on the ground basically. Traction limited driving with 1 CIM is a painfully slow speed, acceleration will take a hit, and you basically just lag behind. Using KOP wheels to lower traction in order to rectify this makes you lose in pushing. Adding a shifter can help then, but you're still getting up to 7-8fps rather slowly and with a high current draw. 4 motors can give you a nice 6.5 fps or so with a good balance of current draw, acceleration, and traction-limited-ness. Your drivetrain is the absolute most important mechanical system on the robot. Before you shortchange it, make sure you fully understand the tradeoffs and do the math.