I installed the feedforward from HEPI L4C to stage 1 of the ISI. The results are really good for a first try. Isolation at the resonance of the chamber around 8Hz is really improved by the feedforward. However, Isolation is deteriorated around 1Hz. With some tuning, it will be reduced.
I have attached the calibrated spectra of stage 2 motion in the X&Y and Z directions measured this morning. The damping, feedback, feedforward and the sensor correction were engaged in the best case.