After talks with Gabriele today about CHARD, and his interesting find about ETMY, I checked the full actuation model for the quad suspensions.

This model takes into account the various cross-couplings we have in our DRIVEALIGN matrices:  If Gabriele was driving pitch at ISCINF, these signals get fed to length for some actuation stages.  Then we have to worry about the length-to-pitch coupling of the suspensions.

The code reads in every relevant SUS filter module at a given gpstime (ISCINF, LOCK, DRIVEALIGN), the on/off switch values for the lower stages, and txts of the MATLAB quad suspension model.

I plotted below the pitch-to-pitch and yaw-to-yaw couplings mirroring Gabriele's first two plots from alog 43797.  The model matches very well with non-ETMY test mass responses, and there is no cross-coupling term which explains ETMY's phase lag.

I also get all other DOF_to_DOF couplings, plotted here for the interested.