[Rana, Gabriele, Jenne, Jamie, Lisa, Rana]
We have tuned the oplev servos for PRM, BS, ITMX, ITMY. For each, we measured the servo transfer function. Most had a UGF ~ 3Hz. For those, we increased the gain by a factor of 2, and engaged the 3.3Hz resonant gains. The other case, such as PRM yaw, the gain was already okay, we just needed to engage the resonant gain. We also checked the new phase margin, and for some of them switched the elliptic lowpass to 50Hz rather than 30 or 35.
Before and afters:








We need to, as a last check, look at the spectra before and after to ensure that no modes (like bounce or roll) are newly excited. |