Our current limiting sounds similar to 930's, though maybe not as sophisticated as you describe. I've already described our system in
this thread, but i'll summarize it here too:
We didn't do any integration in an attempt to predict and preempt a circuit breaker tripping. We simply sense the current being drawn by our drive motors, and programmatically limit the power requested of the drive system.
Each time through the control loop, if the current being drawn by any one of the drive motors is above a certain threshold, the program scales back the power being requested of all the drive motors. The scaling factor starts at 100%, and every time through the control loop that the current is above the threshold, the factor is cut back by 5 percentage points (but not below 10%.) Once the current gets back below the threshold, each time through the control loop the scaling factor is increased by 1 percentage point until it gets back up to 100%.
I was able to experimentally determine a threshold which would prevent the breakers from tripping even with the wheels stalled when pushing against an immovable object.
Quote:
Originally posted by kmcclary
Has anyone implemented any of the following?
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- How to throttle back multimotor drives CORRECTLY to prevent backdriving any of the motors
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As I was tuning our system, it appeared to me that the only thing required to keep our drive from being back-driven was to not allow the scaled back pwm value to fall into the "dead zone" between 117 and 137.