Lecture 1 ME 176 1 Introduction
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The document provides an introduction to control systems engineering, defining key terms like controlled variable, manipulated variable, and feedback control. It describes the basic components and configurations of control systems, including open-loop and closed-loop designs. The introduction also covers analysis and design objectives for control systems, like transient response, steady-state response, and stability. It outlines the typical design process and gives examples of control system applications in various fields like aerospace, manufacturing, and power generation.
Lecture 1 ME 176 1 Introduction
- 1. ME 176 Control Systems Engineering Department of Mechanical Engineering Introduction
- 2. Introduction: Definition of Terms Control means measuring the value of a 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 level. controlled variable - quantity or condition that is measured and controlled manipulated variable - quantity or condition that is varied by the controller so as to affect the value of the controlled variable Systems consists of subsystems and processes (or plant) assembled for the purpose of obtaining a desired output with desired performance, given a specific input. process - any operation to be controlled plant - physical objects functioning together to perform an operation performance - measured criteria on systems actual against desired output Department of Mechanical Engineering
- 3. Introduction: Definition of Terms Input - stimulus, or external variable applied to the system. Output - actual response from the system. Disturbance - signal that tends to adversely affect value of the output of a system. Feedback Control - an operation that, in presence of disturbance, tends to reduce the difference between the output of a system and some reference input and that does so on the basis of this difference. Department of Mechanical Engineering
- 4. Introduction: Primary Purpose Power Amplification - Tractor arms for road construction. Remote Control - NASA's Mars Rover Opportunity Convenience of Input Form - Temperature control systems. Compensation for Disturbance - Speed control systems. Robot Control Systems Department of Mechanical Engineering
- 5. Introduction: History Liquid Level Control (300 BC) Ktesibios - Water Clock Philon - Oil Lamp Steam Pressure and Temperature Controls (1681) Denis Papin - Safety Valve Cornelis Drebel - Temperature Control Speed Control (1745) Edmund Lee and William Cubitt - Windmilll James Watt - Flyball Speed Governor Department of Mechanical Engineering
- 6. Introduction: History Stability, Stabilization, and Steering (19th Century) Maxwell, Routh, and Lyapunov - Stability of Motion Henry Bessemer - Steering and Stabilization of Ships 20th Century Developments Nicholas Minorsky - Automatic Control Systems Bode, Nyquist and Evans - Linear Control Systems Analysis and Control Theory Contemporary Applications Digital Computer Compound Application Department of Mechanical Engineering
- 7. Introduction: System Configuration Open Loop systems "Do not correct for disturbances and are simply commanded by input." Department of Mechanical Engineering
- 8. Introduction: System Configuration Closed-loop (Feedback Control) systems "Sensitivity, with ability to correct for disturbances by providing feedback" Department of Mechanical Engineering
- 9. Introduction: Analysis & Design Objectives "Analysis is the process by which a system's performance is determined." "Design is the process by which a systems performance is created or changed." Transient Response Steady State Response Stability Department of Mechanical Engineering
- 10. Introduction: Design Process Department of Mechanical Engineering
- 11. Introduction: Design Process Department of Mechanical Engineering
- 12. Introduction: Design Process Department of Mechanical Engineering
- 13. Introduction: Design Process Department of Mechanical Engineering
- 14. Introduction: Design Process Department of Mechanical Engineering
- 15. Introduction: Design Process Department of Mechanical Engineering
- 16. Introduction: Design Process Department of Mechanical Engineering
- 17. Introduction: Design Process Department of Mechanical Engineering 1st Quarter: Introduction, and Modeling of Systems 2nd Quarter: Analysis of Transient Response, and Multiple Subsystem 3rd Quarter: Analysis of Stability and Steady State Error 4th Quarter: Root Locus Techniques and Design Control Systems Engineer : Cross domain experience. Top down approach.
- 18. Introduction: Review Department of Mechanical Engineering 1. Name three applications for feedback control systems. 2. Name three reasons for using feedback control systems. 3. Name one reason for not using feedback control systems. 4. Give three examples of open loop systems. 5. Functionally, how do closed-loop systems differ from open-loop systems? 6. Name the three major design criteria for control systems. 7. Name the two parts of a system response. 8. Physically, what happens to a system that is unstable. 9. Instability is attributed to what part of the total response. 10. Describe a typical control system analysis task. 11. Describe a typical control system design task. 12. Name three approaches to the mathematical modeling of control systems. 13. Briefly describe answers in no. 12.
- 19. Introduction: Functional Block Diagrams Department of Mechanical Engineering 1. A temperature control system operates by sensing the difference between a desired temperature and the actual temperature using a thermostat, which in turn controls the opening of a fuel value an amount proportional to this difference. The fuel in turn powers a heater, which controls the temperature. 2. A university wants to establish a control system model that represent the student population as an output, with the desired student population as an input. The administration determines the rate of admissions by comparing the current and desired student populations. The admissions office then uses this rate to admit students. Draw a functional block diagram showing the administration and the admissions office as blocks of the system. Also show the following signals: the desired student population, the actual student population, the desired student rate as determined the the administration, the actual student rate as generated by the admissions office, dropout rate, and the net rate of influx.
- 20. Introduction: Functional Block Diagrams Department of Mechanical Engineering 3. An aircraft's attitude varies in roll, pitch, and yaw as defined in figure. Draw a functional block diagram for a closed-loop system that stabilizes the roll as follows. Using pilot controls to enter the desired roll information, the system then measures the actual roll angle with a gyro and compares the actual roll angle with the desired roll angle. The airlons respond to the roll angle error by undergoing and angular deflection. The aircraft responds to this angular defletion . producing a roll angle RATE.
- 21. Introduction: Functional Block Diagrams Department of Mechanical Engineering 4. In a nuclear power generating plant, heat from a reactor is used to generate steam for turbines. The rate of the fission reaction determines the amount of heat generated, and this rate is controlled by rods inserted into the radioactive core. The rods regulate the flow of neutrons. If the rods are lowered into the core, the rate of fission will diminish; if the rods are raised, the fission rate will increase.By automatic controlling the position of the rods, the amount of heat generated by the reactor can be regulated. Draw a functional block diagram for the nuclear reactor control system: