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Unread 15-01-2014, 23:03
F Elliott F Elliott is offline
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FTC #8114
Team Role: Teacher
 
Join Date: Dec 2013
Rookie Year: 2013
Location: Dallas
Posts: 56
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Re: [FTC]: Can I add non-slip material to 4" Tetrix Wheels?

The team spent some time tonight discussing the drive question. It's been very interesting as a teacher listening to and letting these debates play out. Someday I'm going to record a few and let our administrators here them --- these are engaged passionate students!

I think the choice is between two mortors driving four wheels via a gear train or four motors, one on each wheel. The debate was intense. I vetoed chain drives, mechanum, and tank treads since we have none of the parts and no experience with them.

During the discussion the areas we were lacking information and experience were the following:

1. Four wheels driven independently by four motors... This would be the simplest mechanically and lowest cost approach since would just replicate the two drive wheels we have. We were not sure how you synchronize the two wheels on each side if each wheel is driven by its own motor. In the software? Would this mean we would need a total of four motor encoders as well? And PID control? If so we only have one encoder and we were never able to get PID to work with our two current motors.

2. Two wheels on each side driven via a gear train by one motor on each side. Minimal SW impact but this means lots more gears and axles. Will there be enough power now with one motor powering two wheels and all the gears if we gear 1:1? Seems unlikely. Robot weighs 20 lb

3. If we tried to drive a geared side with two motors wouldn't they fight each other if they weren't somehow synched using encoders and PID?

I can we us doing all kinds of cool experiments in the off season!
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