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Unread 17-01-2017, 11:36
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Re: Robust way to rotate an 18 inch square plate 90 degrees.

Quote:
Originally Posted by paul.dornfeld View Post
Weight with its load ~ 3 lbs (I estimate the CG arc will be about 12 inches from center )
The measurements are the overall volume, the actual plate is more like an "L" shape probably made out of 1/8 to 1/4 inch thick material. (don't know yet, but I think the weight is correct either way).

Would like it to complete its 90 degree rotation in < 3 seconds (more like a slamming up action)

As an aside, who makes FRC compliant actuators, please? The one company I found last night https://www.servocity.com said his motor wasn't compliant.

Thank you.
This sounds like a good job for a light pneumatics. If you need intermediate positions, look into a heavy duty servo or light motor (e.g. some flavor of PG) with sensor feedback.

The FIRST servo rules have relaxed significantly in 2017 (after a significant relaxation in 2016), so you may want to re evaluate the compliance yourself. IIRC, the only servo specific requirements this year apart from how you power and control it (R36) are that it have a retail value under $75 (R32).

Edit: When setting up pneumatics, you should make sure that your mounting gives you good leverage at your angles of greatest load. For lifting a plate/box around a horizontal hinge, the cylinder should be pushing (or, less optimally pulling) just about straight up at the bottom of the stroke, but can be at a relatively shallow angle (e.g. 30 degrees) at the top of the stroke, because the CoG isn't rising very much there. Going the other way will require a much larger cylinder that will slam the plate to the top of the travel because it is overpowered there.
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Last edited by GeeTwo : 17-01-2017 at 11:41.
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