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Unread 25-02-2016, 02:06
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Re: Diagnosing Belt Skip Under Load

Quote:
Originally Posted by Mike Marandola View Post
Maybe the shafts holding the small pulleys are deflecting. What kind of belts/pulleys are you using?
VexPro HTD. We had considered switching to a different tooth profile, but I am not sure if belts/pulleys are available that wouldn't require us to remount the gearbox at a different location. Remounting should be possible, but is currently a challenge with the holes already in place for this mounting and the clearance holes for shafts/bearings.

Quote:
Originally Posted by Travis Schuh View Post
Some thoughts on solving this problem is you could go to wider belts and larger belts, or switching to something like #35 chain (hopefully combined with larger sprockets). You could also try motion profiling your arm to reduce the loads on the belt when lowering the arm.
Wider belts is an attractive option, we actually have spares of those pulleys (18T & 36T) and I wonder if simply doubling up on belts on either side might help.

As for controls, we tried a trapezoidal ramping function in combination with PID but couldn't get good motion out of it (usually the I term would build up too quickly while the voltage ramped up). PID is critical for us because we need to be able to hold the arm steady for our ball-intake position. Motion profiling might be a better option, though it would be new for us.