[Aritomi, Nakano, Kokeyama]
As Nakano-san reported before (klog 1474), dither alignment sensing control (asc) of IMC is successful.
We dithered the testmass of MCe at 10 Hz and MCi at 15 Hz in yaw direction. (one of coils of MCo wasn't attached,so we didn't dither MCo)
Then we demodulated the transmission from IMC at each dither frequency and fed back to the yaw motion of each dithered testmass.
In the attached file, dark green line is the transmission from IMC, light green and purple lines are the control signals of MCe dither and MCi dither.
MCe dither turned on first (-2.5 Minutes) and then MCi dither turned on (-1.8 Minutes).
Finally, IMC settled down to the optimal alignment point and the transmission from IMC increased.
UGF of this control is around 0.01 Hz. (openloop was not measured precisely)
However, when we increased the filter gain to increase the UGF, IMC lost lock. I'm not sure what the cause is.
We'll also have to see the stability of this control.
