[BBray_T1296]

Here is the main problem with anything more than a single or 2 speed gearbox:
Time

The field is 54 feet long, and (this year) 25 feet wide. The furthest distance you could possibly need to travel, straight line, is ~60 feet.

The question is not whether you get more top speed out of 4 gears, but whether or not you can do such a thing in 60 feet, including stopping. If you have a straight line top speed of 30fps (or 1116.437fps for that matter), if you cannot reach said speed by the time you cover the length of the court, you have an improperly designed gearbox.

We ran a 5.5fps and a 15.5fps drivetrain this year, with 6 CIMS in ballshifters. The actual, tested, realistic acceleration time we got from starting in first gear, reaching 5.5fps, then shifting up "on-the-fly", only gained us hardly measurable time. We, like most if not all teams who use shifting gearboxes do not use them for decreased acceleration time, but for torque vs speed selection-low gear for plowing, high-gear at all other times. Integrating some smart code to decide which gear to use based on wheel speed is definitely a good thing, but not why the shifters were chosen for the design.

Is such a challenge to build a compact 4speed transmission a great off-season project? sure- but consider this before using it on next years game: the field is everything.
If you save 0.1 seconds crossing the field with your new system, but you only do it 2-3 times a match, is it worth all that effort just for the extra 0.3 seconds you gain? Also, if we have another game like 2010 or 2010, having more speeds is useless because the field is even smaller.


Also, will you ever get a straight-line path? more often than not, no. There will be some field element, or one of the other 5 robots in you way, that you will have to steer around. Steering slows you down, in all cases of tank drive, as you must slow one side to turn that direction. That will further hinder your capability.


Sorry for being the Debbie-Downer, but that is my $0.02