Feedback & Control Systems I: Introduction

• This is an Introduction to Feedback & Control Systems I, by Cenon D. Lumabad III, MSc, ECE
• This is for DCEE24 Feedback & Control Systems, AY 2024-2025

Topics Covered

• CvSU Vision & Mission
• Class Administration
• Introduction
• Brief History

CvSU Vision

• The premier university in historic Cavite is globally recognized for excellence in character development, academics, research, innovation, and sustainable community engagement.

CvSU Mission

• Cavite State University provides excellent, equitable, and relevant educational opportunities in the arts, sciences, and technology through quality instruction and responsive research and development activities.
• It produces professional, skilled, and morally upright individuals for global competitiveness.

DCEE24A – Feedback & Control Systems

• Deals with time and frequency response of feedback control systems
• Type: Lecture (3-hr) & Laboratory (3-hr)
• Units: 4
• Prerequisite: EENG60 | Electrical Circuits 2
• Upon completion of the course, students will:
  • Familiarize with various systems with control mechanisms
  • Analyze systems and apply control theory to improve systems
  • Understand feedback control
  • Apply system-level thinking
  • Demonstrate knowledge in feedback & control by creating a prototype

Course Requirements

• Class Attendance
• Class Participation
• Quizzes
• Homework, Prob Sets
• Major Exams
• Student Portfolio

Classroom Decorum

• Students are required to:
  • Wear ID at all times.
  • Wear prescribed uniform (except Wed).
  • Clean the classroom before and after classes.
  • Avoid unnecessary noise.
  • Practice good manners and right conduct at all times.
  • Practice gender sensitivity and awareness inside the classroom.
  • Come to class on time.

Examination Policy

• Quizzes may be announced/unannounced
• Midterm and Final Examinations are scheduled.
• Cheating is strictly prohibited:
  • A student who is caught cheating will be given a score of "0" for the first offense.
  • For the second offense, the student will automatically receive a failing grade in the subject.
• Students who will miss a major examination, a laboratory exercise, or a class project may be excused and allowed to take a special exam, conduct a laboratory exercise, or pass a class project for any of the following reasons:
  • Participation in a University/College-approved field trip or activity.
  • Due to illness or death in the family.
  • Due to force majeure or natural calamities.
  • The student must present a written and signed excused letter.

Grading System for Lecture (75%)

• Midterm Exam: 20%
• Final Exam: 20%
• Attendance: 10%
• Outputs/Portfolio: 25%
• Quizzes/Long Exams: 15%
• Class Participation: 10%
• Total: 100%

Grading System for Laboratory (25%)

• Exam (Practical/Written): 50%
• Laboratory Reports: 30%
• Attendance/Participation: 20%
• Total: 100%

Standard Transmutation Table

• 96.7 - 100.0 = 1.00
• 93.4 - 96.6 = 1.25
• 90.1 - 93.30 = 1.50
• 86.7 - 90.0 = 1.75
• 83.4 - 86.6 = 2.00
• 80.1 - 83.3 = 2.25
• 76.7 - 80.0 = 2.50
• 73.4 - 76.6 = 2.75
• 70.00 - 73.3 = 3.00
• 50.0 - 69.9 = 4.00
• Below 50 = 5.00

What is Control Systems Engineering?

• It is an interdisciplinary field that deals with control systems, applying control theory to design systems with desired behavior.
• In practice, sensors are used to measure the output of the process being controlled, providing corrective feedback to achieve desired performance.
• Focuses on implementation of control systems mainly derived by mathematical modeling of a diverse set of systems.

Brief History

• 300 BCE - Ktesibios's water clock was the 1st feedback control device invented by Greek Engineer Ctesibius of Alexandria in Egypt.
• 1620 - Drebbel thermostat, Drebbel invented the thermostat for the incubation of eggs using mercury.
• Industrial Revolution - 1769 was a period of major technological and economic change that began in the 18th century and transformed societies from agrarian to industrial.
• 1788 – Watt's Centrifugal Flyball Governor was used for speed regulation of steam engine.
• 1793 – Breguet's Pendule Sympathique, Breguet – watchmaker invented Pendule Sympathique a closed-loop feedback system to synchronize pocket watches.
• Design of feedback control systems up to the Industrial Revolution was by trial-and-error + great deal of engineering intuition, and was more of an art than a science.

Birth of Mathematical Control Theory

• 1868 – Maxwell's paper "On Governors," James Clark Maxwell explained instabilities of the flyball governor using differential equations on his 1868 paper.
  • Maxwell (Father of Control Theory) work is the first significant work to mathematically analyze a control system
• 1877 - E. J. Routh's Stability Criterion
  • E. J. Routh provides a numerical technique to determine stable roots called Routh Stability Criterion.
• 1895 - A. Hurwitz's stability criterion
  • A. Hurwitz provides his own stability criterion.
  • Both works contributed to the Routh-Hurwitz Criterion.

19th Century

• Euler, Laplace, Heaviside & Fourier also developed different methods for mathematical modeling.

Early 20th Century

• Two important occurrences related to control theory:
  • Development of the telephone and mass communications
  • World Wars

1920 – 1930's

• Frequency domain analysis developed by Fourier, Laplace, Cauchy and others were used in communication systems

The World Wars

• 1910 Sperry invented gyroscope for stabilization and steering of ships
• 1922 N. Minorsky introduced his three-term controller for ship steering - PID Controller
• Aside from ship control, another problem during WWII is accurate pointing of guns aboard moving vehicle
• 1934 Hazen coined Servomechanism - implies a master/relationship in systems
• 1947 N. B. Nichols developed his Nichols Chart for the design of feedback systems
• 1948 W. R. Evans presented his Root Locus technique – providing direct way to locate closed-loop poles in s-plane

1950s

• Much control work was focused on the s-plane and obtaining a desirable closed-loop Step Response.

Space Age

• 1957 Soviet Union launched Sputnik - world's 1st artificial satellite
• 1960 Major development independently occurred in theory of communication & control (time-domain):
  • Navigation - Inertial Navigation System
  • Optimal Control – Kalman Filter
  • Estimation Theory
  • Nonlinear Control Theory (US) extended work of Popov and Lyapunov in nonlinear stability
  • Major development in another area starts digital computer technology
• Control design turned back to time domain techniques.
• Automatic control design rose to activities in USA.
• Design of a control system for advanced nonlinear multivariable systems is impossible in the frequency domain.

Development of Digital Computer

• 1830 - Babbage introduced modern computer principles
• 1948 - Neumann directed construction of IAS stored-program
• 1960 - 2nd Gen. Computers which uses solid-state tech
• 1965 - DEC built PDP-8- beginning of Microcomputer industry
• 1969 - Hoff invented the microprocessor
• Computers two main purposes in Modern Control
  • Matrix Design Equations
  • Implement modern control & filtering schemes on actual systems

1950s

• Theory of sampled data systems
• Computer-controlled oil refinery at Port Arthur
• Development of Nuclear Reactors
• Motivate works in industrial process control & instrumentation

1970 – Present

• Information/Computer Age
  • 1970 Astrom et. Al. established the digital control in process applications
  • 1974 Application of digital filtering theory investigated
  • 1983 Introduction of PC made design of modern control systems possible for individual engineers
• Thereafter, abundance of control system software's was developed.

Supplementary Activity

• Readings: Chapter 1 - Schaum's Outline of Feedback and Control Systems