1. EE 475 Automatic Control Systems Fall 2011 MWF 11:00-11:50 am 1252 Howe Hall

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3. Basic Information
Instructor Contact Information
Degang Chen, 2134 Coover Hall
Office Hour: MWF 12:00 – 2:00 pm
Or any other time convenient to you
Please include "EE475" in the subject line in all communications to avoid auto-deleting or junk-filtering TA
No TA support this year
Needs creative way of grading HW

4. Final Grade Weighting Schedule
Homework average: 15%
Midterm exam1: 20%
Midterm exam2: 20%
Final exam: 30%
Quizzes: 15%
Discretionary bonus: 0-5%
Fixed Grading Scale:
A: – 100% A–: 85 – 89.9%
B+: 80 – 84.9% B: – 79.9% B–: – 74.9%
C+: 65 – 69.9% C: – 64.9% C–: – 55.9%
F: < 50%

5. Catalog Description
E E 475. Automatic Control Systems. (3-0) Cr. 3. F.Prereq: 324. Stability and performance analysis of automatic control systems. The state space, root locus, and frequency response methods for control systems design. PID control and lead-lag compensation. Computer tools for control system analysis and design. Nonmajor graduate credit.

6. Prerequisite by topics
Knowledge and proficiency in Matlab
Concept and solution of linear ordinary differential equations
Laplace transform and its applications
Poles, zeros, transfer functions, frequency response, root locus, Bode plots, Nyquist plot
Vectors and matrices
Complex numbers

7. OBJECTIVES
On completion of EE 475, the student will be able to do the following either by hand or with the help of computation tools such as Matlab:
Define the basic terminologies used in controls systems
Explain advantages and drawbacks of open-loop and closed loop control systems
Obtain models of simple dynamic systems in ordinary differential equation, transfer function, state space, or block diagram form
Obtain overall transfer function of a system using either block diagram algebra, or signal flow graphs, or Matlab tools.
Compute and present in graphical form the output response of control systems to typical test input signals
Explain the relationship between system output response and transfer function characteristics or pole/zero locations
Determine the stability of a closed-loop control systems using the Routh-Hurwitz criteria
Analyze the closed loop stability and performance of control systems based on open-loop transfer functions using the Root Locus technique
Design PID or lead-lag compensator to improve the closed loop system stability and performance using the Root Locus technique
Analyze the closed loop stability and performance of control systems based on open-loop transfer functions using the frequency response techniques
Design PID or lead-lag compensator to improve the closed loop system stability and performance using the frequency response techniques

8. Topics Covered
Review of signal systems concepts and techniques as applied to control system
Block diagrams and signal flow graphs
Modeling of control systems using ode, block diagrams, and transfer functions
Modeling and analysis of control systems using state space methods
Analysis of dynamic response of control systems, including transient response, steady state response, and tracking performance.
Closed-loop stability analysis using the Routh-Hurwitz criteria
Stability and performance analysis using the Root Locus techniques
Control system design using the Root Locus techniques
Stability and performance analysis using the frequency response techniques
Control system design using the frequency response techniques
If there is time, Control system design using the state space techniques

9. Student behavior expectations
Full attendance expected, except with prior-notified excuses
On-time arrival
Active participation
Ask questions
Answer questions from instructor or students
Be cordial and considerate to students and TA
Help each other in reviewing notes, HW, Matlab
Promptly report/share problems/issues, including typos on slides, or misspoken words from instructor

10. Prohibited behaviors Any foul language or gestures
Comments to other students that are discriminatory in any form
Any harassments as defined by the university
Academic dishonesty
No alcohol, drugs, or any other illegal / improper substances
Snacks/drinks OK as long as you don’t spill and clean up

11. Accommodation/Assistance
Please let me know if you
Have any special needs
Have disability in any form
Have any medical/mental/emergency conditions
Have field trip / interview
Have special requests
Want me to adjust lecture contents/pace
Can also consult me if you
Would like to seek advice on any professional or personal issues
Would like to have certain confidential discussions

12. Collaboration And Helping Each Other
For tasks intended for group work, you are expected to find a partner and share the tasks among the group members. In a group project, effective teamwork is critical to maximize the productivity of the whole group. In the submitted work, identify components and indicate percentage contribution by each member to each component.
For tasks not intended for group work, individual submission is required. In this case, you are encouraged to discuss among your friends on how to attack problems. However, you should write your own solution. Copying other people’s work is strictly prohibited.

13. Academic dishonesty
Cheating is a very serious offense. It will be dealt with in the most severe manner allowable under University regulations. If caught cheating, you can expect a failing grade and initiation of a cheating case in the University system.
Basically, it’s an insult to the instructor, the department and major program, and most importantly, to the person doing the cheating. Just don't.
If in doubt about what might constitute cheating, send to your instructor describing the situation. If you notice anyone cheating, please report it to the instructor or the TA. Do not deal with it yourself.

14. Discrimination
State and Federal laws as well as Iowa State University policies prohibit any form of discrimination on the basis of race, color, age, religion, national origin, sexual orientation, gender identity, sex, marital status, disability, or status as a U.S. veteran. Language or gestures of discriminatory nature will not be tolerated. Severe cases will be reported to appropriate offices. See ISU policies at
Let us make every effort to work together and create a positive, collegial, caring, and all-supportive learning environment in our classroom, laboratory, TA office, and instructor office.

15. Disability accommodation
Individuals with physical or mental impairments who are otherwise qualified to perform their work or pursue their studies may request reasonable accommodations to enable them to work or continue their studies.
If you believe you have learning disability, you must contact Student Disability Resources at the Academic Success Center to initiate the accommodation process.

16. Accommodation for religion based conflicts
Iowa State University welcomes diversity of religious beliefs and practices, recognizing the contributions differing experiences and viewpoints can bring to the community. Students with religion based conflict should talk to the instructor and appropriate university offices to request accommodations at the earliest possible time.

17. Control Systems History
Watt, steam engine speed control governor
Black, feedback amplifiers
Minorsky, ship steering stability
Nyquist, closed-loop stability from open-loop
Hazen, Servomechanisms
Bode, Bode plot, and BP based control design
Evans, root locus plot, RL based design
Kalman, state space, controllability, Kalman filter
Anderson…, linear optimal control

18. Figure 1-1 Speed control system.

19. Control Systems History
Bellman, dynamic programming
Pontryagin, maximum principle
Lyapunov, nonlinear systems
Sastry…, adaptive control
Arimoto, learning control
Doyle…, robust control
Byrnes/Isidori, nonlinear regulation
Devasia/Chen/Paden, stable inversion
Kokotovic, backstepping

20. Control System Terminology
Input - Excitation applied to a control system from an external source.
Output - The response obtained from a system
Feedback - The output of a system that is returned to modify the input.
Error - The difference between the reference input and the output.
Discuss Slide

21. Negative Feedback Control System+ + +
CONTROLLED
DEVICE
CONTROLLER -
1. All weapons system must have some form of control system. Normally a negative feedback control system.
2. Input: Stimulus or excitation to a control system from an external source usually in order to produce a specific response from the system.
Example: signal sent from a radar dish to the weapons control computer.
3. Output: The response from the system such as a gun turning toward target.
4. Feedback: That portion the output of a system that is returned to modify the input and thus serve as a performance monitor.
Example: The gun needs to tell the weapons computer where it is pointing so that the computer can compare that to where it should be pointing.
5. Error: The difference between the input stimulus and the output response.
Specifically the difference between the input and feedback.
Discuss the + and - signs on the Comparater and the error is reference signal minus the feedback signal.
FEEDBACK
ELEMENT

22. Negative Feedback Control System+ + +
CONTROLLED
DEVICE
CONTROLLER -
1. All weapons system must have some form of control system. Normally a negative feedback control system.
2. Input: Stimulus or excitation to a control system from an external source usually in order to produce a specific response from the system.
Example: signal sent from a radar dish to the weapons control computer.
3. Output: The response from the system such as a gun turning toward target.
4. Feedback: That portion the output of a system that is returned to modify the input and thus serve as a performance monitor.
Example: The gun needs to tell the weapons computer where it is pointing so that the computer can compare that to where it should be pointing.
5. Error: The difference between the input stimulus and the output response.
Specifically the difference between the input and feedback.
Discuss the + and - signs on the Comparater and the error is reference signal minus the feedback signal.
FEEDBACK
ELEMENT

23. Types of Control Systems
Open-Loop
Simple control system which performs its function with-out concerns for initial conditions or external inputs.
Must be closely monitored.
Closed-Loop (feedback)
Uses the output of the process to modify the process to produce the desired result.
Continually adjusts the process.
1. Introduction:
a. Most equipment have some form of a controller to make it function.
b. Most have something more than just an on/off switch as a controller.
c. Two major types of controllers in use:
2. Open-Loop.
a. Performs its action without regard to the output or any external input.
Example: The controller on a washing machine.
a. It will run the washer through the cycle without regard for the cleanliness of the clothes in the machine, if there is soap in the machine, temperature of the water, how much clothes are in the machine, etc.
3. Closed-Loop (Feedback)
a. Senses the output of the controller or process.
b. Uses this output to change the process to meet the desired result.
c. Controller can determine how accurate the output is or if it producing the
desired result.
d. Control action depends on the output of the system.
Example: Aircraft auto Pilot set to keep plane at altitude.

25. Advantages of a Closed-Loop Feedback System
Increased Accuracy
Increased ability to reproduce output with varied input.
Reduced Sensitivity to Disturbance
By self correcting it minimizes effects of system changes.
Smoothing and Filtering
System induced noise and distortion are reduced.
Increased Bandwidth
Produces sat. response to increased range of input changes.
1. Increased Accuracy
a. Ability to faithfully reproduce the output.
2. Reduced Sensitivity to Disturbances
a. Ability of the system to produce the same output repeatedly in spite of variations and fluctuations within the control system (worn gears, sticky components etc.)
b. Changes within the system are reduced and the effects of the changes can be minimized.
3. Smoothing and filtering. Undesirable effects of noise and distortion within the system are reduced.
4. Increased Bandwidth. Can operate satisfactorily over a wide range of frequencies or variations in the input.

26. Major Types of Feedback Used
Position Feedback
Used when the output is a linear distance or angular measurement.
Rate & Acceleration Feedback
Feeds back rate of motion or rate of change of motion (acceleration)
Motion smoothing
Uses a electrical/mechanical device call an accelerometer
1. Discuss slide.
2. A you can see from the example of the gun turret, these types of feedback provide additional information that is used to improve the response time of the system.
- The light on when the proper position was reached. But...
- The additional information modifies the system response and improve the response time.
3. This additional information when add to the feedback loop is call DAMPING.

27. Fire Control Problem Present Future Position Ship’s Bearing Heading
Present Range
Future Range
Range Change
Bearing
Change
Go over diagram to show the geometry of the problem. Show
a. Development of Bearing Change
b. Development of Range Error
Goal is to determine the target’s course and speed so we can predict where the target will be at the time it takes the weapon to reach the target.
We are trying to solve a solution with respect to time:
ie. We want to adjust the aim point such that the target and the weapon arrive at the same point at the same time.
We then convert the Bearing change to a time reference by calling it a bearing rate. ie. how much the bearing changes with time. We do the same thing with range.
Getting this solution is just a little better than a trial and error process. It is a multiple step process when one solution is tried and the errors fed back to improve the next solution trial. This is called an iteration process.

28. A German anti-aircraft 88 mm gun with its fire-control computer from World War II.
Displayed in the Canadian War Museum.

29. Fire Control Problem Input Target data Own ship data Computations
Relative motion procedure
Exterior ballistics procedure

30. Fire Control Problem Solutions Weapons time of flight Bearing rate
Line of Sight(LOS): The line between the target and the firing platform
Speed across LOS
Future target position
Launch angles
Launch azimuth
Launch elevation
Weapon positioning orders
The above determines weapon trajectory: The line the weapon must travel on to intercept the target.

31. The Iterative Process to the Fire Control Solution
Step 1
Step 2
The iterative process starts with an initial guess of the solution. The aiming point is put into the computer and the position of the target is computed at the time the weapon reaches the aim point. The error is fed back to refine the aim point. For example:
Step 1
a. The aim point is where the target is at the time of fire. At impact the target will move down its track.
Step 2
a. The bearing error is used to change the bearing of the aim point.
b. Note: If only used bearing error, the weapon would always fall short so
the range error is also used
The iterative process continues until the the weapon and the target’s solution intersect at the flight time of the weapon.
As a review:
What Information does the computer need to solve this problem?
1. Target position
2. Target data over a period of time to determine target course speed and range.
3. Weapons speed to compute time of flight
Step 3
Last Step

32. A 3-Dimensional Problem
Line of Sight
Present Range
1. In the previous examples we were concerned with two dimensions. The actual problem could be 3-dimensional.
2. The problem is essentially the same but have different names.
Target
Elevation
Gun
Elevation
Horizontal Reference Plane

33. Solving the Fire Control Problem
Continuously Measure
Present Target Position
Stabilize Measured
Quantities
Compute Relative
Target Velocity
Ballistic
Calculations
Relative
Motion
Time of
Flight
Future
Target
Position
Prediction Procedure
Unstabilized
Launch
Angles
Environmental Inputs
Launch Angles
(Stabilized)
Weapons Positioning orders
1. Continuously measure target Position.
2. Stabilize Measured Quantities
a. Remove the effects of own ship roll pitch and yaw
b. Standardize points of reference (difference between location of sensors
and weapons.
3. Compute Relative Velocity of the Target
4. Prediction Procedures
a. Does the trial and error flight calculation to weapon and target interception at the flight time of the weapon.
b The output is the launch angles as if the launch platform is stabilized.
(i.e. not rock, roll, pitch and yaw)
5. Motion of the launch platform is added to the launch angle to give the weapons position order.
6. Sequence is repeated.

34. Temperature control system.

35. Block diagram of an engineering organizational system.

36. Idle-speed control system.

37. Conceptual method of efficient water extraction using solar power.

38. Important components of the sun-tracking control system.

39. Antenna azimuth position control system:
a. system concept;
b. detailed layout;
c. schematic;
d. functional block diagram

40. a. Video laser disc player; b
a. Video laser disc player; b. objective lens reading pits on a laser disc; c. optical path for playback showing tracking mirror rotated by a control system to keep the laser beam positioned on the pits.
(a)
(b)
(c)
© Pioneer Electronics, Inc.

41. Computer hard disk drive, showing disks and read/write head
Courtesy of Quantum Corp.

42. Response of a position control system showing effect of high and low controller gain on the output response
High gain; fast but oscillating
Control goal; fast reaction, lower overshoot, less settling time