User`s guide

A Servomechanism Example
8-5
Aclosed-l oopmodelfortheelectrohydraul i cvalvepositioncontrolcan besetup
as follows.
Figure 8-1: Feedback Control for an Electrohydraulic
Servomechanism
K(s) represents the compensator for you to design. This compensator can be
either a gain or a more general LTI system.
Alinearized plant model fortheelectrohydraul ic position control mechanism is
given by
For this example, you want to design a controller so that the step response of
the closed-loop system meets the following specifications:
• The two-percent settling time is les s t han 0.05 seco n d s.
• The m ax imum overshoot is less than 5 percent.
For deta ils on ho w these specifica tio ns are def ined, see [2] .
In the remainder of this chapter you learn how to use the R oot Locus Design
GUI. In the process, you design a controller to meet these specifications.
+
–
G
servo
s()
K(s)
Compensator
Servomechanism
Ram Position
Desired Ram
Position
Linearized
G
servo
s()
410
7
×
ss 250+()s
2
40s 910
4
×++()
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