Elli, Thomas, Stefan

After Jeff redid the PR3 M3 P2P and Y2Y transfer function measurements, we designed actuation filters for high bandwidth feed-back to PR3.
We decided to use M3 on PR3, offloaded to M1 (top).

The filters we used are:
PIT PR3^-1: zpk([0.1+i*0.82;0.1-i*0.82;0.5+i*3.4;0.5-i*3.4],[0.5+i*3.02;0.5-i*3.02;11.1111+i*38.4258;11.1111-i*38.4258],1,"n")
YAW PR3^-1: zpk([0.2+i*1.23;0.2-i*1.23;0.3+i*2.95;0.3-i*2.95],[0.3+i*2.5;0.3-i*2.5;11.1111+i*38.4258;11.1111-i*38.4258],1,"n")

In both filters the design philosophy was to compensate the mechanical poles with a slightly lower Q digital zero,but such that we never run out of phase for unconditional stability. The resulting transfer function works as resonant gain, suppressing the motion on resonance.

Attached are loop transfer functions, both measured (red) and calculated based on Jeff's measurement times the applied filter.