LIGO Document T1800301-v1
- We plan to use feedforward control to improve DARM around 0.1-0,3 Hz. The idea is to use the suspension point motion measured by the GS13 on ST2 and feed it to the top mass of the Quadruple suspensions. In order to do this properly we need to consider the cross coupling to the angular degrees of freedom. Additionally we observe non reciprocity on the top mass Length-Pitch transfer functions. All this means we need to study the control scheme in the real system to be able to inform our decision to implement it.
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