The new PRM ASC design
Pitch
FM1: zero at 0Hz, pole at 2000Hz, gain at 2000Hz = 2000
FM5: (boost)
zero: f: 0.5Hz q: 1 / 4Hz, q: 2 / f: 1Hz, q: 3
pole: f: 2Hz q: 3 / f: 2.7Hz, q: 2 / f: 1Hz, q: 15
FM9: (HF Roll-off)
pole: f: 40Hz q: 1/Sqrt(2) (2nd order butterworth)
Servo gain: -0.023
Yaw
FM1: zero at 0Hz, pole at 2000Hz, gain at 2000Hz = 2000
FM5: (boost)
zero: f: 0.5Hz q: 1 / 4Hz, q: 2 / f: 1.5Hz, q: 10
pole: f: 1.02Hz q: 10 / f: 3Hz, q: 5 / f: 2Hz, q: 6
FM9: (HF Roll-off)
pole: f: 40Hz q: 1/sqrt(2)
Servo gain: -0.027
The loop gains were adjusted to have the UGFs of 10Hz. The measured openloop transfer functions were compared with the model.
The transfer functions for yaw are well matched. However, the pitch ones don't. It seems that the pitch loop has extra low pass
which I can't locate. The possibility is the analog electronics of the pitch loop.
The effect of the control between 0.3Hz to 3Hz are well represented by the model. The attachment 2 shows the free running
angle fluctuation, the ones with the control engaged, and the estimated spectra. Indeed, the estimated spectra well represent
the measured angular spectra. |