Luck: When preparation meets opportunity.

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• Luck When preparation meets opportunity.
• Life is what happens while you are busy making
  other plans. (John Lennon)

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Engineering Systems Analysis

• EGR 386
• Fall 2003

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Introduction

• Assignment Read Chapter 1

Introduction history basic terminology More
terminology point of view Examples Closed-loop
vs Open-loop Assignments
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History

• 17?? James Watt centrifugal governor, speed
  control of steam engines
• 1922 Minorsky steering ships, stability from
  DEs
• 1932 Nyquist stability of closed-loop systems
  based on closed-loop response to steady-state
  sinusoidal inputs
• 1934 Hazen introduced term servomechanism for
  position control systems, servomechanism capable
  of closely following a changing input
• 1940s frequency-response methods, Bode diagram,
  based design methods
• Late 1940s to 1950s root locus methods due to
  Evans
• Late 1950s 60s 70s state space modeling and
  design, optimal control
• 1980spresent H? robust control

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Basic Terminology
The controlled variable is the quantity or
condition that is measured and controlled. The
manipulated variable is the quantity or condition
that is varied by the controller so as to affect
the value of the controlled variable. Control
means measuring the value of the controlled
variable of the system and applying the
manipulated variable to the system to correct or
limit deviation of the measured value from a
desired value.
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More Terminology
A plant performs a particular operation. It is
the physical object to be controlled A process
is any operation to be controlled. Processes can
be chemical, economic, biological, etc. A system
is a combination of components that act together
and perform a certain objective. A disturbance
is a signal that adversely affects the value of
the output of a system. May be internal or
external. Feedback control refers to an
operation that, in the presence of disturbances,
tends to reduce the difference between the output
of a system and some reference input and does so
on the basis of the difference.
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Point of View

• Control systems are made up of components each of
  which
• Have input and output signal(s) (Examples of
  signals position, velocity, acceleration,
  temperature, voltage, current, concentration,
  etc.)
• Process their inputs to produce their outputs
  (outputs are caused by the interaction of the
  input and the component)
• Are described by differential equations
• Engineers produce mathematical models of the
  components so they can design controllers.

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Examples
Speed Control Temperature Control Light-level
control voltage-level control pH control etc
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Closed-loop vs Open-loop Control
A system that maintains a prescribed relationship
between the output and the reference input by
comparing them and using the difference as a
means of control is called a feedback control
system. Closed-loop control system feedback
control system. Block diagrams have
loops. Those systems in which the output has no
effect on the control action are called open-loop
control systems. Block diagrams do not have
loops.
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Assignments

1. Be able to define the following controlled
   variable, manipulated variable, plant, process,
   system, disturbance, feedback control,
   closed-loop control, open-loop control.
2. Know the Point-of-view of this course.

Quiz Containing one of the questions above.
In class Question One or both above.