According to the suggestion of Raffaele, I checked the diagonalized sensing signal (driving signal). I found there are quite a lot of coupling between each DOF. Therefore, I optimized the invertion matrix. After that, I also increase the gain of each loop.
New driving matrix:
| WFS1 | WFS2 | |
| input_p | 1 | -0.6 |
| end_p | 1 | 1.65 |
| input_y |
-1 |
0.8 |
| end_y | -1 | -2 |
New gain:
input yaw: 10
input pitch: 8
end yaw: 10
end pitch: 12
The comparison of new spectrum and old one is shown in the attached figure. We could see:
1. The coupling is bascially not visible in the spectrum.
2. The control bandwidth is increased.
3. The AA helps to reduce input mirror pitch motion to 2urad. Reduce input mirror yaw motion to 1urad.
4. The AA helps to reduce end mirror pitch motion to 1.2urad. Reduce input mirror yaw motion to 0.8urad.
As we concived that the mirror angular motion results in the difficulty of mode matching, this situation maybe improved by the AA control.
