[GeeTwo]

Originally Posted by IKE

You could have them all hooked together and at a higher weight than robot can pull (say 300 lbs), then record initial weight and weight at stall and the difference would be the pull weight.

Originally Posted by alecmuller

I like that - like some of the teams used with their hooks to lift totes & hold them a fixed distance apart this past year. It would also provide a "stair-stepped" resistance instead of suddenly hitting the full load all at once. Unfortunately I'd need to get lighter weights (because my ~20lb weights are very low resolution).

Not quite what I think Ike had in mind - something more like:

• Place a single load on the back end of the cord that is greater than the maximum pull your robot can lift, but less than the top limit of your scale.
• Put the scale under the load, in the configuration ready to be lifted.
• Record the reading on the scale.
• With someone watching the scale, turn the robot on, and gradually increase the pull until a wheel slips.
• Record the lowest weight on the scale just before spin-out.
• Subtract the pre-spin-out weight from the full weight to get tension in the cord at the point of maximum traction.
• Add/multiply whatever fudge factor is needed to account for the friction in the pulleys to get the maximum traction force.