Omni Directional movement for tank drive.

[Hawiian Cadder]

the main goal of this is not to make the robot faster, it is to remove traction and torque from the factors that influence how difficult a robot is to push, thus allowing a team with single speed gearboxes to effectively block a team with 2 speed gearboxes.

[Ether]

Originally Posted by SamM

Though your numbers are off by an order of magnitude or two

He forgot to divide 120 rpm by 60 to get 2 rev/sec

[Jeffy]

Originally Posted by Hawiian Cadder

the main goal of this is not to make the robot faster, it is to remove traction and torque from the factors that influence how difficult a robot is to push, thus allowing a team with single speed gearboxes to effectively block a team with 2 speed gearboxes.

Curiosity:
How does this eliminate traction and torque as factors?

On traction:
A single speed robot CAN block a 2 speed robot.
Assume:
1. The single speed robot is oriented so that the motors do not backdrive when being pushed.
2. The tractive force between the robot and the surface is larger for the single speed robot than the two speed robot.
3. The two speed robot has enough torque to provide more force than the frictional force provided by the wheels and "spin" the wheels/tires.

The frictional force between the robots contact surface (ussualy wheels/treads) is what keeps it from being pushed. For the most part, in FRC, any robot with AM tread can be an effective "blocker".

[Hawiian Cadder]

in my experience teams that attempt to block sideways are easily "spun" also AM tread is not even close to the grippiest material used, the blue mcmaster tread is much gripper.

[SamM]

If you watch videos of meltys (google: spinning tortoise), you'll note as soon as they contact something they bounce away in the opposite direction. All the offensive robot would have to do is bump into the melty, and the reaction force would move it back and to the side. The offensive robot would move back a little but much less because it has much better traction.

I admit it would be cool to see, but i don't see it being a viable design for FIRST.

[Doug G]

This reminds me of Kingman's (FRC# 60) 2002 robot. It could pick up two 180 lb goals and spin them around a center turret. While they never used it during competition, I saw them demo it for a TV crew at SVR that year. It is one of the most impressive and scariest things I've seen a robot do.

[stundt1]

Originally Posted by Grim Tuesday

Our team has a running joke of inventing "mecanum treads".

Hehe we made some last summer a prototype.