DC servo vibrates at rest

[Karl_T]

I have a CNC mill with DC brushed servos controlled by an 1880 Galil card...

It is an old machine that has worked well for a great many years. I recently moved it 2000 miles. Just powered it up today. The Y axis will vibrate at the stop position. Move it and it may be fine or it may vibrate again. Put your hand on the servo and its rotating back and forth rapidly just a half degree or so.

What should i do to correct this?

Karl

Similar Threads:

• Need Help!- DC Servo Vibrates on Fanuc 6M
• Need Help!- torch vibrates when moving slow
• BOB has DIR,STP,GND,ENA driver has CP+,CP-,CW+,CW-,Rest-, Rest+.
• Problem- Okuma LB300-M. X axis servo vibrates whit peaks at every 3 mm increment, any idea?
• Need Help!- Motor just stalls and vibrates!

[Al_The_Man]

Usually with Galil that has torque mode drives, it is in the PID tuning parameters.
i.e. too much gain.

[Karl_T]

These ran fine for more than a decade. Just re tune???

I was guessing the move shook something loose or broke?

[Jim Dawson]

Retuning is what I would do also. Try bumping up the KD parameter, makes it react just a bit slower without affecting the stiffness much. I guess the other possibility could be encoder noise, loose connection? Maybe look at the raw encoder data to see how stable it is..