Hardware Reference
In-Depth Information
4
3
2
1
0
−1
0
0.5
1
1.5
x 10
−3
10
5
0
−5
−10
0
0.5
1
1.5
x 10
−3
Time (s)
Figure 3.104: Microactuator and estimator responses with reduced order mi-
croactuator models for r=4 µin (y
M
: solid line, y
M
: dashed line) and 35 µin
(y
M
: dotted line , y
M
:dash-dotline).
The robustness of the modified DMS scheme can be further investigated
by evaluating the maximum MASSC. Table 3.9 summarizes the maximum
MASSC obtained through simulation for three cases:
• Case 1: use equations 3.182 and 3.183 to control the plant described
by the equations 3.180 - 3.181 according to the scheme presented in the
block diagram of Figure 3.90,
• Case 2: use the proposed modified DMS scheme with a full order model
of the microactuator
P
M
used to estimate the output of the secondary
stage, and
• Case 3: use the modified DMS scheme but P
M
is the DC gain of the
P
M
only.
Figure 3.105 plots the MASSC versus DC gain error expressed as a percent-
age for the linear control scheme. It shows that the MASSC decreases from
28 µin to 7.6 µin as the DC gain error varies from −50% to +50%. For the
modified nonlinear control scheme with full order and reduced order models
