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Unread 17-01-2016, 13:31
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Joe Johnson Joe Johnson is offline
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AKA: Dr. Joe
FRC #0088 (TJ2)
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Re: ⁶ CIM drive-train brown out

Quote:
Originally Posted by MaGiC_PiKaChU View Post
This robot is currently running on a Roborio. and still no Brownouts

Edit: I should add that we had each wheel independently powered by it's own CIM through Versa planetaries
I really don't like this topology.

First, VPs are awesome but... ...they are not as efficient as straight up spur gears - not usually a problem but the drivetrain is almost always the most power hungry system on the robot, a few % of efficiency on this system matters.

Second, with 6WD you have at most 4 wheels on the ground at any one time. The CIMs on the wheel in the air is doing nothing. WORSE, when you get in a pushing match, you will have most of your weight on the rear wheels as you push against the other robot. In this case, nearly all the power to the ground will be coming from those back 2 CIMs, the front 4 will be providing next to nothing.

In cases like what you have described, I believe it is much better to have the wheels driven by a common drive system (chain, gears, belts, ...). In this type of system, all the CIMs have the opportunity to drive whatever wheels are on the ground. If you have a good reason not to do this, fine, but if you can, then you do.

Dr. Joe J.
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