System
Performance Study Guide
(Links
to material about system performance)
System performance is what is it all about. It includes topics like
system accuracy, speed of response, stability and relative stability.
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Why learn about system
performance?
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System performance is
important. You design control systems so that you can obtain good
system performance. 'nuff said.
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What should you know to
learn about system performance?
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What do you need to know
about system performance?
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Time response of a system
is important, and there are several ways of measuring various aspects of
the time response of a system.
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The accuracy of a system
is usually measured using Steady State
Error (SSE).
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The speed of response
is measured in many different ways. It gets complicated because higher
order systems can't be described with a single time-constant.
Higher order systems often use arbitrary measures of speed of response
like rise time and settling
time. You will find that in first order systems rise time and
settling time are related
to the time constant.
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We are usually concerned
with closed loop systems, and you need to be able to relate open loop characteristics
to closed loop characteristics that determine performance. A lot
of that relies on interpreting a root
locus.
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In many cases, design
of a closed loop system is done using frequency response methods, and you
need to do things like relate
closed loop bandwidth to rise time, etc.
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How do you use measures
of system performance?
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When you design a control
system you are manipulating parts of the system in a closed loop in order
to make the overall system - the closed loop system - behave in a way that
you want - which may be a way specified by a purchaser, etc. You're
dealing with measures of system performance, and they will be measured.
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Problems
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Additional Information