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Unread 05-08-2010, 15:13
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Re: Drive train questions

Quote:
Originally Posted by BJC View Post
Actully, I disagree. I think that your robot should be geared to go as fast as the drivers can control it. If you look at teams such as 67, 1114, and 254 (just off the top of my head) they all have extreamly fast drivetrains that they can all control very well. This is generally because their drivers are very experienced from a combination of past seasons and practice robot driving.
Because games in FIRST are unfailingly "who can do more/faster" senerios if you want to win you have to go fast. So if you are really good but not that fast you can never hope to be as good as the robots that are both.

As for low gear make it low enough to push stuff but not low enough that other robots can run away, that aside its all preferance.

my 2 cents
Those teams also understand the tradeoffs of having 14-16fps drive trains.

To go 14fps+, a robot that expects to have all of its drive train motors last the entire season would need all 4 CIM motors on the drive train. The robot better also have a low gear because simply turning the robot would result in extreme torque loss at any gear ratio that gives such a high speed. I suspect that's why the poof's advertised speeds are 7fps / 16fps on a couple of their recent robots rather than 4-5 / 16. I also don't ever notice the poofs trying to push another robot in a defensive manner; usually I see them pushing through a situation and then zooming away, but I've only seen a small percentage of their recent matches.

To go even faster, even more drive train motors are needed. For a 60-lb (or so) robot that tumbled around the track in 2008, 148 used 6 motors on their 3-wheel crab that (iirc, off the top of my head) went somewhere around 18fps.

Additionally, there are some slide decks on AndyMark's website that give insight as to why their SuperShifters have the ratios that they do -- anything lower than 4-5fps for low gear has a tendency to make the wheels slip on carpet.

I do agree with the "who can do more faster" concept, but that really only applies to Einstein-grade teams who are anticipating competition against other teams just like them. I say that because they also need extra practice in controlling the drive train at high speeds (as well as fast manipulators as high speeds), thus they allot time for extra practice & sensor integration before competition. Ergo, versus an average team an Einstein-grade team would (probably) win regardless of what drive train speed it chose so long as the speed was "fast enough".
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