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Unread 08-01-2015, 16:38
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Re: toughbox mini mecanum

Quote:
Originally Posted by asid61 View Post
I would assume that shifting would get you finer control over the position in low gear, but a very fast high gear, which may or may not be necessary depending on your strategy.
Fast is good if you are trying to get the cans in the middle quickly, for example.
Fast is good, yes, but that doesn't always mean a higher top speed. If you're starting in between the auto and landfill zone, going for the center of the step, you're driving five feet. At distances this short, you can easily gear your robot so quickly that you actually lose the race to a slower top speed robot factoring in acceleration. Even if it's just a few milliseconds slower, you're giving up low speed precision to have a high top speed you'll almost never actually reach. Acceleration models are available on CD to help verify this sort of thing, just keep in mind that the constants people use in these models vary.

What I'm trying to say is that you can't really spout out old "rules of thumb" as fact this year, in a game that isn't open field and for a different drivetrain configuration. Especially when you have never built a mecanum drivetrain. If you give advice without qualifying your lack of experience, teams may be led to make decisions they otherwise wouldn't that could end up hurting them. I've made this mistake before and i'm sure teams have made missteps as a result, hopefully minor.

This might be totally made up, but I've also heard that strafing performance decreases at higher speed gearing. This is probably a function of roller efficiency, if this is the case. I lack experience in this specific aspect of mecanum drives, though.
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