Quote:
Originally Posted by Tom Line
The difference between an 18 fps drivetrain (no shifting) and a 6 fps drivetrain over 10 feet is about .4 seconds. Shifting introduces another variable, but you can see where I'm going with this. Erring for a higher gear ratio will rarely leave you disappointed. Due to acceleration timing, a top speed of 10.6 fps is only .02 seconds slower than an 18 fps over 10 feet without shifting.
In fact, over 10 feet a robot geared for 18 fps will only hit about 15 fps.
This segways into a very interesting argument about when you should design for shifters.
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There's another question implicit here: are teams interested in long-distance sprints? Ever since we went to the rectangular field (the short 48 ft field in 2000, and the long 54 ft field in 2003), most games have had common, reasonable strategies that involve a sprint of 30 ft or more, with modest arc and elevation changes. (2001, 2007, 2010 and 2012 are the biggest exceptions.)
2008 is the canonical example, since cycle time was the only critical factor for the lap-bots. 2011 was another game where cycle time was critical, and speed in the open was available.
Another valuable aspect of speed in the open is building momentum for defence. Sometimes a pushing match isn't necessary—hitting the opponent out of position at the right moment is frequently a good strategy. It's a minimal demand on your gameplay time, with a large effect on the opposition. (2003 was the canonical example of this, but it was handy in all of the games that didn't have safe zones for scoring robots, 2004 in particular.)
Also, position denial is an effective form of defence. In 2010, being a fraction of a second faster than your opponent side-to-side between the goals would have been enough to stop them from kicking a ball past you (even given drivers' reaction times).
More generally, FRC robots have a hard time pushing while twisting—so get parallel to your opponent, and hold them against the wall by keeping pace with them. That requires you to be as fast as the expected opponent, but not much else. For that reason, it's a good, simple way for the robots lacking manipulators to operate effectively—and might be a good reason for them to err a little higher on the speed spectrum. In this case, the fact that the acceleration from rest is so closely matched actually favours the defender, because he can easily keep alongside a robot geared lower, while still being able to execute the same maneoeuvre against faster opponents.