Hardware Reference
In-Depth Information
y
ref
=21
µ
in
50
40
30
20
10
0
−10
−20
−30
−40
0
0.5
1
1.5
2
2.5
x 10
−3
time is sec
Figure 3.95: Response to 21 µin step input. Solid line: combined output,
dashed line: microactuator output, dash-dot line: microactuator input.
Table 3.8: VCM Loop Gain Margin vs. MASSC
GM Estimated MASSC Actual MASSC
in dB
in µin
in µin
14.6
42.9
40
12.9
31.7
33.5
11.6
27.1
27
10.4
23.6
23.5
9.5
21.3
21
8.6
19.2
19
7.8
18
18.1
NonlinearObserverbasedDMSControl
In the previous designs, saturation in actuators was ignored and the controllers
were designed and their performances were evaluated assuming non-saturating
actuator. However, it is an usual practice to limit the magnitude of the input
voltage applied to the microactuator to protect it from being damaged. That
is,
⎨
u
M
if
u
M
≥ u
M
u
M
= sat(u
M
)=
u
M
if
u
M
<u
M
< u
M
(3.171)
⎩
u
M
if
u
M
≤
u
M
where
u
M
and u
M
represent the minimum and maximum allowable control
input to the microactuator.
