R&D (FilterCavity)
YuhangZhao - 23:43, Wednesday 17 March 2021 (2405)
Auto-alignment driving matrix improvement

Marc and Yuhang

Marc provided us a code written by Julia Casanueva Diaz, which was used by Marc to do FIS auto alignment for Virgo.

After reading this code together, I found out what can be improved for the construction of driving matrix. Especially, I finally understand what is the meaning of matrix of inversion. The idea is the change of basis after inversion. With this in mind, we checked again the sensing matrix and inverted it. We got following driving matrix

 

Pitch

Yaw

 

WFS1

WFS2

WFS1

WFS2

Input mirror

7.37

-4.98

-1.71

1.65

End mirror

6.64

9.69

-1.65

-4.41

With this driving matrix, we did preliminary check of Input and End mirror pitch/yaw reconstructed spectrum. Compared with the old measurement (elog2263elog2245), it seems the reconstruction is more reasonable (attached figure).

More investigation and optimization will be done soon.

Images attached to this report
2405_20210318132052_05.png