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Unread 02-03-2015, 17:58
Jefferson Jefferson is offline
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AKA: Jeff Clements
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Re: Elevator Motion Profiling / PID Ramping

Quote:
Originally Posted by Aero View Post
Our elevator is way too fast.

We're currently using a standard PID loop, but it accelerates ridiculously quickly and throws totes.

I've looked into motion profiling, but can't see an easy way to (quickly) dynamically generate profiles between two arbitrary points on our elevator.

Is motion profiling the best solution here, or is there a simpler way to stop our elevator from accelerating too fast?
We used a pretty simplistic approach to ramping/position control this year:

First, capture the time the new setpoint was set (rampStartTime)

ramp = rGain*(GetClock() - rampStartTime)
output = error*ramp
constrain output in a reasonable range for the current load

Adjust the rGain to get the ramp up you want and the constraints to limit the top end.