PID

Did you follow one of the servo tuning tutorials, to tune your PID settings?
Such as this one:
gnipsel.com/linuxcnc/tuning/servo.html

You also need to view your f-error with a bit of perspective, the movement you are seeing there in that photo is only +/- a few encoder counts, with the largest peak only -7 counts. What is your encoder scale? Do you have a value for the dead band setting? Sometimes setting that to 1.5-2x the encoder scale can help to quiet a nervous joint at rest.

Bahaa_Asem wrote:

No movement, change in axis values, or halscope vibrations take place when drive is disabled...., I already tried a lot of values for pid..

 

Did you try the open loop test in pncconf?
It is used to confirm the analog setting actually moves the motors and that the encoders count in the right direction.

Why set the deadband to 1.5-2X the encoder scale? And how to know the encoder scale or check them if I calculated it wrong?

The encoder scale is the distance your machine moves for one encoder count. It is a setting in your ini config file. If the scale is set wrong the machine won't move the correct distance.

Having a small dead and setting can help to quiet servo dithering by telling the pid "your close enough.