pic: MOEnarch Swerve Drive

[Ether]

Originally Posted by nathannfm

it takes ~15% more force to pull/push the robot side to side or front to back

Would you please post your data and test procedure?

[nathannfm]

Originally Posted by Ether

Would you please post your data and test procedure?

Sure, all from memory but it should be good enough.

First I had to build The Bathroom Scale of Science, the "force gauge" we used to test this because the real one we had in the lab maxed out at 50lb. The bars that stick out from the sides are the handles and the X that crosses the face of the scale has 4 ropes that converge at a shackle that was placed around a 1x1 frame member on the robot in the bumper zone. The wheels were then locked by jamming a scrap between the spokes. The robot was pulled with the ropes remaining as horizontal, and the scale remaining as vertical as possible to the ground. A reading of ~120lb was observed on the scale. The wheels were then switched to those with diagonal tread, the same procedure was followed and a reading of ~140lb was observed. A ~15% increase.

We also used a similar procedure to demonstrate how ineffective trying to drive out of a T-bone is. This time the wheels were unlocked and I pulled sideways acting as an opposing robot pushing from the oppisite side as our driver floored it (and the robot started to drive in a circle around me with a radius of the rope (~5ft)) you could see the scale instantly drop from a reading of ~140lb to something like 60lb (I don't remember the exact number but it was something drastic)

We again used the test to determine that 2" wide 4" dia wheels were ~15% better than 1 inch wide wheels. Take 4 1" wide wheels, place them on the four corners of the robot, lock them, drag. Place 4 more 1" wide wheels on the same axles, lock them, drag.

*All tests performed on actual FRC carpet

[Ether]

Originally Posted by nathannfm

The robot was pulled with the ropes remaining as horizontal, and the scale remaining as vertical as possible to the ground. A reading of ~120lb was observed on the scale.

Was this the breakaway force, or the min force to continue motion?

Was the height of the horizontal rope above, below, or at the height of the wheel axes?

[nathannfm]

Originally Posted by Ether

Was this the breakaway force, or the min force to continue motion?

The force to continue motion, but surprisingly the difference was only a few pounds. Nothing like the dramatic example of the spinning wheels.

Originally Posted by Ether

Was the height of the horizontal rope above, below, or at the height of the wheel axes?

It was about 2 inches above, in the middle of our bumper (one bumper removed for test to attach shackle to frame)

[TheLoveGouru]

Hey Everyone!

This is just a quick update on the progress of the MOEnarch drive system.
We have mounted the four modules onto the square chassis and it's working smoothly.

This is the Facebook link to the video:
https://www.facebook.com/video.php?v...type=2&theater

As you will notice, the robot doesn't have any encoders on the modules just yet. We are looking to set those up by the end of next Monday and have a robot-centric swerve drive ready to go before Winter Break.

[Gdeaver]

Sounds like a swerve, kind of moves like a swerve, it must be a swerve. Welcome to the 3 degrees of freedom club.