Limiting Drivetrain Motors

[Jon Stratis]

Part of me likes the idea, part of me doesn't.

In once sense, it would be nice to limit power to help preserve the robots all these teams build. This was definitely the hardest hitting year I've seen... and I know my team's robot took more damage from impacts this year than we did from falling off the tower multiple times last year!

In another... going up against stronger robots with more powerful drive trains does present an engineering challenge. It's a challenge to build robust robots. It's a challenge to design a strong drive train that avoids tripping the main breaker. It's a challenge to play any FRC game well.

Rather than setting a more-or-less arbitrary limit on "drive train power", I'd rather see the rules limit overall motors to a number reasonable for the game being played. Look at this year, for example:

6 CIM - 337W each
4 Banebots - max of 273W each
4 AndyMark 9015 - 45W each
4 Denso - 18W each
4 Bag/Mini-CIM - max 229W each
2 Window - 23W each
2 Vex 2-wire - 4W each
1 snow blower - 30W each

(Per 2014 rules and 2014 motor data sheet)

That's a lot of power - 4366W, if my math is correct. When I look back over previous years, our robots have never been anywhere close to that:
2014: 5 CIM, 1 RS-550 - total of 1939W
2013: 4 CIM, 2 mini-CIM, 3 AndyMark, 1 Window - total of 1964W
2012: 4 CIM, 2 RS-550, 2 FP, 1 AndyMark - total of about 2300W (I *think* the FP's were around 200W each... hard to remember)
2011: 4 CIM, 2 RS-550, 1 FP, 1 Window - total of about 2300W

I would contend that we're getting a lot more power in the rules than robots really need to be successful.

Another side of this, of course, is in the design of the game. Having game aspects that require a lot of power from the motors means you need to have more motors available. This year, we had a game where all game piece manipulation and scoring could fairly easily be done with a relatively small amount of motor power (in a large part thanks to stored energy devices like catapults that use springs or hammers that use gravity). I know we got ours for about 400W this year. Compared to previous years (600W+ in 2013 to climb the tower, 800W+ in 2012 to shoot the basketballs, 600W+ in 2011 to manipulate the tubes), this required fewer motors to accomplish, which would leave more for the drive train.

So for me, I would vote for fewer motors allowed overall, with game play designed to offer a tradeoff between power in the drive train and power for accomplishing other game tasks.