ChE 448 Process Control for Mechanical Engineers

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ChE 448Process Control for Mechanical Engineers

• Winter 2009

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Logistics

• Instructor Dave Shook
• Shook_at_ualberta.ca
• Office CME 268A, office hours TBA
• 492-3301
• Teaching assistants Natalia Mrcos and Xing Jin
• Lectures Tuesday and Thursday 930-1050
• Seminar Tuesday 800-850 CME 342, Thursday
  800-850 CME 340
• Computer lab CME 244, experimental labs CME 274
• Officially T/W/R/F 200-450 PM
• Actually M/T/W/R/F 200-450 PM and 500-750 PM
• Three experimental labs, one computer lab
• Weeks of Jan 12, Feb 2, Mar 2 (computer), Mar 17
• Teams of 3, all reports to be done as teams
• First lab is next week, so get in groups this
  week and sign up on door of CME 274
• Recommended text Seborg, Edgar and Mellichamp,
  2nd Ed.
• Some assignments will be straight out of the text

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Evaluation

• Marks
• Assignments 20
• Labs 20
• Mid-term examination 20
• During regular class time on Thursday, 12
  February
• Final Examination 40
• Total 100
• Assignments are to be done on Engineering paper
  with answers clearly indicated.
• Lab reports are to include an executive summary
  and sample calculations in addition to results
  and discussion. More information will be provided
  in the lab manual.

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Grading

• Raw marks used throughout the course
• Grades (F to A) assigned to final distribution
  of total marks for the course
• Based on absolute achievement and relative
  performance in the class
• Questions regarding assignments should be
  directed to the TA.

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Plagiarism, Cheating, Misrepresentation of Facts,
and Participation in an Offence

• Plagiarism submitting the words, ideas, images
  or data of another person as the Students own
• Cheating No Student shall
• During an exam or similar Obtain (or attempt to
  obtain) information from another Student or
  unauthorized source, give (or attempt to give)
  information to another Student, use (or attempt
  to use or possess for the purposes of use) any
  unauthorized material
• Represent or attempt to represent him or herself
  as another, or have (or attempt to have) himself
  or herself represented by another
• Represent anothers substantial editorial or
  compositional assistance on an assignment as the
  Students own work
• Submit, without the written approval of the
  course instructor anything for which credit has
  previously been obtained, or which has been or is
  being submitted in another course or program of
  study
• Misrepresentation of Facts for the purpose of
  obtaining any advantage
• Participation in an Offence encouraging,
  advising or knowingly aiding (directly or
  indirectly) another person in the commission of
  an offence
• Consequences 0 on an assignment up to expulsion
• Due Process You have the right to appeal
• See the dontcheatsheet at http//www.uofaweb.ualb
  erta.ca/governance/pdf/200820Aug20Don27t20Chea
  tsheet.pdf

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Why are we here?

• Control is one of the topics in engineering. You
  need it for your degree.
• It teaches you useful skills and techniques for
  analyzing systems that change over time
• Your designs will end up moving, or containing
  materials that move that motion must be
  controlled.
• You may want to be a manager some day. You need
  to be able to understand the specialists that
  report to you.
• Not every facility has a control engineer. You
  may need to apply this sooner than you think.

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Course Objectives

• By the end of this term you will be able to
• Understand a control problem
• Specify a control objective
• Design a controller
• Implement the controller
• Assess its performance, and improve it if
  necessary
• You will also be able to
• Understand when a process is sufficiently
  complicated to require a specialist
• Work with and manage control engineers
• But youre going to have to pay attention and
  work in the labs.

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Labs

• Will teach you practical issues in controller
  design, while reinforcing theory
• 1. Introduction to instrumentation, control and
  process models
• 2. Controller tuning (computer lab)
• 3. Controller implementation and performance
  measurement
• 4. Complete control design and implementation on
  a new process
• Choice cover lab material in class before the
  lab, or go through material in the same order as
  the textbook
• We will try to cover lab material in class before
  the lab.

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Expectations You can expect me to

• Try to explain things clearly, in a logical order
  
• Provide relevant examples and assignments
• Structure and deliver lectures to help you pay
  attention
• Finish lectures on time
• Listen to your questions and act on your feedback

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I expect you to

• Respect other people save phoning, texting,
  talking, reading paper for breaks. Avoid
  distracting other people by arriving late or
  leaving early.
• Respect yourself if you dont understand
  something, chances are that you are not the only
  person ask a question.
• Respect your (or your parents) investment in
  your education attend lectures, seminars and
  labs, and do the assignments.
• Respect the Engineering profession give the
  class a chance. If you dont see why its
  relevant, talk to me after class.

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Why Should I Care?

• Moving systems need to be regulated
• Electronic Stability Control
• Static equipment may contain fluids that need to
  be regulated
• Oil Pressure Regulator
• Pressure Regulator Failure
• Mechanical Engineers work in a multidisciplinary
  environment. You need to understand how control
  issues affect the mechanical design
• BP Texas City
• The techniques and skills of process control can
  be applied elsewhere economics, business
  management, stock market

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Process Control

• The primary objective of process control is to
  maintain a process at the desired operating
  conditions, safely and efficiently, while
  satisfying environmental and product quality
  requirements. The subject of process control is
  concerned with how to achieve these goals. -
  Seborg, Edgar and Mellichamp, 2nd Ed, p. 2.
• Oil pressure regulator
• Cruise control
• Home temperature control (thermostat)

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Exercise Cruise Control

• Work in pairs
• What is the objective of cruise control?
• How does cruise control meet that objective? What
  does it manipulate directly? How is that done?
• What else can affect the vehicles speed? Can any
  of them be measured?
• How is the speed measured?
• How quickly, and by how much, does the speed
  change in response to a change in controller
  output?
• How would you measure how well cruise control
  meets its objective?
• You have five minutes.

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Cruise Control Discussion
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Terminology

• Controlled variable (also called Process
  Variable, Process Value or just PV) the value we
  are trying to control room temperature, car
  speed, etc.
• Setpoint the desired value of the controlled
  variable 110 km/h, 22 degrees C, etc.
• Manipulated variable the variable we can change
  directly throttle position, furnace on/off
  switch
• Disturbance anything (other than the manipulated
  variable) that can affect the controlled variable
• Instrumentation the interface between the
  physical world and computer/logic/calculations.
  Both measurement and actuation.

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Examples
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Control Design Steps

• Define the control objective
• Understand how the process responds to control
  action and disturbances
• Make sure the instrumentation is working
  correctly
• Design a controller for the process that will
  meet the objective
• Examine the complete system to ensure it is safe,
  and will not become unsafe if the process changes

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This design process requires

• A mathematical language describing how things
  respond to inputs
• mathematical models, Laplace transforms,
  transfer functions
• A way to build a model of a system out of
  components, where each component is modeled in
  isolation
• Block diagrams and linear system theory
• Knowledge of standard control techniques
• Lectures
• An understanding of practical issues
• Labs
• A way to describe safety factors for systems when
  the inputs are not known
• Frequency response analysis
• Skill, arrived at through practice
• Assignments, labs

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How this class will work

• PowerPoint, lecture notes and in-class exercises
• Reinforced by assignments
• Lecture notes will be posted on course website
• in incomplete form before lecture
• Complete form after lecture
• Copies of (incomplete) lecture notes will be
  provided for first two weeks, or if not available
  one week in advance.