[Andrew Schreiber]

Originally Posted by Andrew Schreiber

I won't tar and feather you, I'll disagree though.

Just as an example I will use a Joe Johnson's NBD and show what percentage of a mobility system it is compared to the percentage for these mechanisms.

First I have to define what a mobility system is. For the sake of definition I will call it the bare minimum necessary for a robot to move. This means 2 driven wheels and 2 omni wheels, a chassis, associated electronics etc.

TEAM 221 LLC (note that Team 221 is not actually an FRC team, it came out of a FIRST team that Anthony was involved with in the past and is no longer associated with FIRST other than selling parts designed for use in the competition)

2 x CIM motors
2 x swerve modules
2 x omni wheels
Kitbot frame from AndyMark (or IFI depending on preference)
CRio
PD board
Digital breakout board
2 x Victor or Jaguar
Wire
2 x Potentiometer
Programming to control the swerve drive
2 x KOP Wheels


NBD

2 x CIM motors
2 x Dewalt drill transmissions
2 x omni wheels
Kitbot frame from AndyMark (or IFI depending on preference)
CRio
PD board
Digital breakout board
2 x Victor or Jaguar
Wire
Default Programming
2 x KOP Wheels


Seems to me that the Swerve modules are not a significant portion of the drive system. You still have to wire them, still have to assemble them, still have to mount them. Not only that but you have to program them which everyone who does swerve says is the difficult part. Now, in my opinion this is a pretty crappy use of the swerve modules but it DOES show what is needed in a basic mobility system. I could probably assign weights to all of this but they would be highly subjective. Instead I will bring attention to the fact that the Team 221 Swerve actually requires MORE parts than a bare bones set up using Dewalts.

NBD does require you to make some modifications to the Dewalt gearbox but these are all detailed in the white paper so I count this as roughly the same as assembling something based on instructions from an educational experience, I feel this will be the sticking point for many people. Which drive train do people learn more from? To put it bluntly, Team 221 has the distinct advantage here. Programming a swerve drive to work reliably and simply is challenging from a programming point of view. NBD has the benefit of pulling the default code down from FIRST and you are up and running with minor if any changes. Mechanically speaking both teams would learn roughly the same amount assuming neither opened up their parts and toyed with them to figure out how they worked. Electronically the advantage goes to Team 221 again, they get to learn to wire up a potentiometer (or encoder). For these reasons I have to say that the NBD white paper constitutes a higher percentage of a complete mobility system than the Team 221 swerve modules. Furthermore, NBD actually causes students to learn less when assembling it.

Originally Posted by jspatz1

I am not an expert on past FRC rules, don't have them in front of me, and don't have the greatest memory....but, isn't there a rule that says you may not use pre-engineered mechanisms expressly designed to fulfill a primary function of the robot? I don't remember the exact language, but it sure seems to me that systems such as this have crossed that line, wherever it is. As a 4th year team, we have finally gotten ourselves to the point in experience and expertise that we are in the process of developing our own swerve drive. It is a bit discouraging to realize that if you are a team with enough money, you can skip all the engineering and learning, and just buy the major subsystems of your robot.

Out of curiosity, did you even READ this thread? How about the rules?

Originally Posted by Alan Anderson

Stronger competition.

Just to be clear, that's a good thing.

Amen.