Page 359 - Modern Control Systems
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Section 5.7 Performance Indices 333
FIGURE 5.27
Three performance
criteria for a 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
second-order
system.
EXAMPLE 5.7 Space telescope control system
The signal-flow graph and block diagram of a space telescope pointing control
system are shown in Figure 5.28 [9]. We desire to select the magnitude of the
gain, K 3, to minimize the effect of the disturbance, T d(s). In this case, the distur-
bance is equivalent to an initial attitude error. The closed-loop transfer function
Disturbance
TJs)
X(s) +
K 2 Y(s)
* ( . Y ) • Attitude
*- A" s -^
Damping
v.
1V 3
Position feedback
(a)
/?(*•) O O Attitude
FIGURE 5.28
A space telescope
pointing control
system, (a) Block Position feedback
diagram, (b) Signal-
flow graph. (b)
