Hi Josh,
First, I would check that your amplifier is compatible with
your motor..
Once this is verified, it
looks like this could be a tuning issue.
I would then suggest manually tuning your
motor to hopefully eliminate this unsteady behavior.
You can take a look at the
Understanding Servo
Tune document , in particular
the
Manually Tuning a System From Scratch
Tutorial section.
This will help you
achieve a critically damped system for your application.
Please let us know if you would like further
clarification or assistance regarding this issue.
Best Regards,
Vu D