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Originally Posted by Pratik341
During the 2014 season, our robot had a 6 cim, 2 speed drivetrain with a low gear ~4 fps and high gear ~17 fps. The only real times we used high gear was if we needed to travel the length of the field very quickly, or to maneuver around defenders and not push through them. Realistically, your driver will learn to control the high speed and will learn when to shift into high gear. Its mostly a "feel" thing and if your robot needs to go 20 fps, then he will learn to drive it well.
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This is similar to what we did: we stayed in low gear (~8-9 fps) for the majority of the match, mostly using high gear (~19 fps) to make full field runs. Many teams greatly overestimate how much time is spent traversing the field (suitable for high speed), and underestimate how much time is spent lining up passes and shots (suitable for low speed). ~4 fps seems
really slow, even to me though. What shifter did you guys use that has a 4.25:1 spread?
A really fast high gear is sometimes just what you need, though. For example, in
Galileo Match 100 (no video) our alliance partner missed a would-be match winning shot with less than 20 seconds left, and the ball bounced all the way back to our defensive zone. We were able to race back, get the ball, and score it just before time expired.
Some years full field runs happen all the time (2013, 2011 come to mind), others they almost never happen (2012). Whether the ability to save a couple of seconds on each run is worth it depends a lot on your team and the year. It's worth maybe one more cycle, but only if your team can score effectively and quickly.
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The High might sound uncontrollable but what I was thinking is that we could use a button so that when it is pressed, the motors use 100% power but when it isnt it uses 50%. This would essentially give us 4 speeds with a 2 speed gearbox.
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I question why you want to have a secondary "software shifter" when you are planning to have a real shifter on your robot. Why not just use low gear when you want to go slow? In our experience (if I have time I might add the math to back it up) it should give superior acceleration, control, and power consumption. The only drawback I can think of is shifting time, but the COTS shifter options are so good now its not really a big deal.