I tried to compute a rough calibration for the cavity mirrors actuation in DC.

I injected an offest of 10.000 counts in pitch and yaw, in INPUT and END mirrors, one at a time, and record the change seen by OPLEV.

Then I used the calibration reported in entry #1874 to convert it in urad:

Pitch is stiffer than yaw. There is a difference of 15/20% beetween INPUT and END that can come from both errors in OPLEV calibration and actuation unbalance. Also It is a bit strange to me that for the same amout of injected counts pitch motion is larger for INPUT and yaw motion is larger for END.