I should write down what I didn't include for completeness:
1. AA filters
2. AS55 input 60Hz comb filter
3. Violin filters
After discussing with Paco, we agreed that the discrepancy in the MICH calibration might come from the IQ mixing angle which for the IFO is not optimized, while in Finesse is set such that all the amplitude is in one quadrature.
I made some progress in modeling MICH loop.
Putting all the LSC and SUS filters together with the MICH Finesse model I constructed an OLTF model and plot it with the measurement done by Paco and Yuta in this elog (attachment 1).
There are 2 unknown numbers that I had to adjust in order to fit the model with the measurement:
1. The SUS damping loop gain (found to be ~ 2.22), which seems to vary wildly from SUS to SUS.
2. The coil driver gain (found to be 45), which I should measure.
I find coil_driver_gain*SUS_damping_filter_gain by increasing it until the SUS damping loop becomes unstable.
The coil driver gain I find by making the measurement and model overlap.
However, there is one outstanding discrepancy between the measurement and the model: Paco and Yuta measure the MICH calibration to be 1.3e9 cts/m while my model shows it to be 1.3e10 cts/m, an order of magnitude larger.