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Re: Let's Talk About The Bridge:
Based on the calcs that I have done (from the info the video provides plus the other data from the rules, etc.),
- at level, it takes about 15lbs at the edge to tip to an empty bridge
- the bridge must weigh about 200lbs and it's CG must below 9" above the barrier top or else their would be zero restoration torque when down - I estimate it is at 7" FWIW
- If two robots with their combined CG on the centerline of the bridge (and they weigh 143 lbs each), it takes 35lbs to push the edge of the bridge down and their combined CG can move +/-5” without tipping the bridge. If one robot is stationary, the other robot can move +/-10”!
- Further, assuming each has a CG 20” above the plane of the top of the bridge and they are in their nominal balance position, if the bridge is tipped to the ground, it will take 39lbs at the edge of the ramp to lift them back up.
- Continuing… if they move from their together from their nominal position, they will have to move more than 6” up the ramp to make the bridge neutrally balanced (+ a bit more to get it to move). Note that this is beyond the 5" they have from nominal (see above) and they then have to stop the bridge so they will have to move maybe 3" back once they start tipping.
- If only one robot does the rebalancing, they will have to move 12" up the ramp ...
I could go on, but this is all physics guys…
There's a lot to think about... ...fun fun fun...
Joe J.
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Joseph M. Johnson, Ph.D., P.E.
Mentor
Team #88, TJ2
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