F. Clara, J. Kissel, R. McCarthy, G. Moreno

After 
    - sorting out confusion with drive electronics (thanks Fil and Richard!)
    - a few iterations of tuning transfer function amplitudes, 
    - realizing that the eddy current damping magnets may be interfering with / over damping the SUS, 
    - a tweak of a rubbing OSEM, and finally 
    - diagonalizing the longitudinal transfer function (i.e. actuating in Yaw to compensate for the SD OSEM's offset from the center of mass)
Gerardo and I have completed the first set of in-air, driven transfer functions with the recently installed OSEMs on the OFIS. 

Attached are the results, and the resonant frequencies are as follows:
    DOF          Freq (Hz)
     L         0.625 +/- 0.01
     T         0.625 +/- 0.01
     Y         1.039 +/- 0.01

This confirms that AOSEMs, driven with standard 16 bit, 20Vpp DAC, through a (LIGO) standard AI chassis, HAM-A coil driver and ISC/US-style satellite amplifier, pushing 3mm DIA x 6 mm LEN magnets is sufficient to drive the suspension. Further, the OSEM sensor has plenty enough signal to read out the position of the platform, so damping loops will be quite straight forward.

Excellent work design and assembly team!

Details
The data collection templates for the best, diagonalized transfer functions live in
    /ligo/svncommon/SusSVN/sus/trunk/OFIS/H1/OFI/SAGM1/Data/
        2017-10-13_2116_H1SUSOFI_M1_WhiteNoise_L_0p01to50Hz.xml
        2017-10-13_2116_H1SUSOFI_M1_WhiteNoise_T_0p01to50Hz.xml
        2017-10-13_2116_H1SUSOFI_M1_WhiteNoise_Y_0p01to50Hz.xml

Because the new SQZ electronics infrastructure is not yet in place, the drive chain is a temporary setup involving the digital drive chain of OM1 (hence the nonsensical denominator in the labels of the transfer functions), and several in-air cables, including a pin-flip ribbon cable (hence the poor coherence above 5 Hz).

Norna is suspicious of the OFIS's dynamical model put together by Mark Barton back in 2014, so hopefully this data can be used to solidify some degrees of freedom of the model.

I've created a new script that populates the new OFI's infrastructure with a diagonal sensor / actuator basis, which now lives in 
    /ligo/svncommon/SusSVN/sus/trunk/OFIS/Common/MatlabTools/
        make_susofis_projections.m
where the conventions are defined as in E1700352, T1200015, and G1701887. Note I'm also sticking with the SUS convention to have the OSEM2EUL and EUL2OSEM matrices be the *transpose* of each other, and not the inverse. Taking into account that the LF and RT OSEMs (for driving T and Y) are equidistant from the suspended center of mass by l_LR_to_COM = 0.111 [m], but the SD OSEM is offset from the center of mass by l_SD_to_COM = 0.056 [mm], means the drive matrix is 
  | L |    [     +r            +r             -1 ] | LF |
  | T |  = [     -0.5          -0.5            0 ] | RT |
  | V |    [    +0.5/l_LR      -0.5/l_LR       0 ] | SD |

where r = l_LR_to_COM / l_SD_to_COM, and I've abbreviated l_LR_to_COM as l_LR. Actually sticking in the numbers, and reporting as they must be in the CDS system, that's

OSEM2EUL = +1.9821   +1.9821   -1.0000         EUL2OSEM = +1.9821   -0.5000   +9.0090
           -0.5000   -0.5000    0.0000                    +1.9821   -0.5000   -9.0090
           +9.0090   -9.0090    0.0000                    -1.0000    0.0000    0.0000