Re: Resonance in steppers

Hey-
I believe I finally have discovered the problem. It is resonance. At
about 20 - 22 rpm of the stepper (approx . 1.8 ipm table speed) a
resonance occurs that causes the motor to behave very eratically.
Both Xand Y behave this way.
My motor shafts do not have enough length to add mechanical damping.
Where can I find a treatise on adding electrical damping to squelch
this menace?

Jack Ensor

> rosnekcaj wrote:
> > I am losing and gaining position error as my system goes through the
> > gcode I feed it. I suspect it may be due to stepper reonance. Is
> > there any gcode that would pinpoint that this is the problem. In
> > other words how can I find the sensitve velocity that triggers the
> > resonance.
> You don't mention your software, but assuming it has a feedrate
> override, run the same program with different feddrate
> percentages. This should scale all speeds in the program.
> If the position shift is the same for multiple runs at one
> speed, but varies at different speeds, that would indicate a
> resonance problem. If the error seems to be really random, or
> is not affected much by the feedrate override, then it may be a
> step pulse to direction timing problem.
>
> With properly tuned Gecko drives, there is so little stepper hum
> that you aren't sure it is even a stepper system. With some
> other drives, especially of the non micro-stepping variety, the
> stepper whine is quite audible at almost any speed, and becomes
> REALLY loud right near the resonance. If you hear a rising
> whine followed by a loud GRRRONK noise (best I can do spelling
> it out) that is resonance. If there is little whine and no
> grinding noises, you probably do NOT have a resonance problem,
> but either a problem with noise on the step line or a timing
> problem between step and direction.
>
> Jon
>