Hardware Reference
In-Depth Information
Table 3.4: The relationship between the corresponding modes of disk flutter
and the PES
Frequency in Hz Phase in degree Amplitude in dB
504
65.0
-78.5
598
53.6
-74.1
648
44.2
-75.0
694
37.1
-72.3
882
10.7
-81.6
932
-2.2
-80.6
1018
-19.9
-68.0
1248
-45.8
-84.1
servo control block diagram Figure 3.31 to Figure 3.60 where the effect of the
vertical motion of disk is shown as disk's motion entering the VCM output
through a scaling factor K = constant.
−60
−80
−100
−120
10
1
10
2
10
3
100
0
−100
−200
10
1
10
2
10
3
Frequency [Hz]
Figure 3.59: The frequency response from disk flutter measured (velocity out-
put of LDV) to PES.
Feedforward Control Design
Although it is appealing to determine the feedforward compensator via adap-
tive control or self tuning control ([161] [2]), the method based on manipulating
