<R06>

[hdanak]

I don't quite understand the big deal about making the robot heavier... while an increased normal force may improve traction, it won't help accelerating and braking-- if your robot is heavier, it is that much harder to accelerate. I suppose the only advantage is if another robot were to push you, then it would take a larger force to break static friction. I think that the only reason it seems to improve acceleration is that it slows down the motor speed, bringing it below the threshold of breaking static friction (g*u_s). On the other hand, using idler wheels for the purpose of getting robot motion data may waste the weight that it would have driven otherwise... the other wheels must still pull that load.

Hike Danakian, Reseda Regents Robotics (2584)

[Jared Russell]

Originally Posted by hdanak

I don't quite understand the big deal about making the robot heavier... while an increased normal force may improve traction, it won't help accelerating and braking-- if your robot is heavier, it is that much harder to accelerate. I suppose the only advantage is if another robot were to push you, then it would take a larger force to break static friction. I think that the only reason it seems to improve acceleration is that it slows down the motor speed, bringing it below the threshold of breaking static friction (g*u_s). On the other hand, using idler wheels for the purpose of getting robot motion data may waste the weight that it would have driven otherwise... the other wheels must still pull that load.

Hike Danakian, Reseda Regents Robotics (2584)

Increasing robot mass increases the percentage of the robot/trailer system that is applying power to the floor, thereby increasing maximum acceleration and deceleration.

In other words:

F = u*N = u*m*g
F = m*a

The "m" in the top line does not include the mass of the trailer.
The "m" in the second line does

[MrForbes]

The big deal about making the robot heavier, is that you have to accelerate the mass of the robot AND trailer, but you only have the tractive force of the robot wheels to do it. The higher the percentage of total weight that's on the robot wheels, the higher your acceleration can be.

[EricH]

Incidentally, the GDC has clarified that "normal" actions such as handling the orbit balls are perfectly legal even though they increase the normal force slightly, while actions intended purely to increase the normal force are illegal.
http://forums.usfirst.org/showthread.php?t=11275

[Gazelleman]

I think all that FIRST is saying is they don't want people intentionally trying to gain force or traction. The point of the game is to score points in trailers without much traction, not to figure out how to get more traction so you can score more points.