Slow speed jerking

[jrcf...@icloud.com]

I’m running a small gantry router with pic-servo SC’s and PSCNC which is similar (identical?) to Lobocnc. Aside from range of motion and scaling parameters, everything in pscnc.ini is set to default.
When I run at low feedrates, I get a steady jerky or cogging motion. It is pronounced enough to show in the work.
Anything I might try?

[Jeff]

My first guess would be that maybe you need to adjust your servo gains.  If the gains are too low, you may be getting some stick-slip behavior not noticeable at higher speeds.  Try increasing Kp (and maybe Kd if necessary for stability).

-Jeff

[jrcf...@icloud.com]

Thanks, Jeff. That helped quite a bit