Introduction to Control Systems Prof. Marian S. Stachowicz Laboratory for Intelligent Systems ECE Department, University of Minnesota Duluth January 19 - 21, 2010 ECE 3151 - Spring 2010
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Introduction to Control Systems
Prof. Marian S. Stachowicz
Laboratory for Intelligent Systems
ECE Department, University of Minnesota Duluth
January 19 - 21, 2010
ECE 3151 - Spring 2010
Outline
1.1 Introduction 1.2 References for Reading1.3 History of Automatic Control 1.4 Terms and Concepts1.5 The Control System Design Process1.6 Applications1.7 Three Examples of the Use of Feedback
Control Systems
Introduction
Control
• The word control is usually taken to mean :
- regulate,
- direct,
- command.
•
Control Systems
Control and politicians
• Control is a sequence of decisions aimed at the attainment of specified objectives in an environment of uncertainty and presence of disturbances.
Control Systems
Control system
• A control system is an arrangement of physical components connected or related in such a manner as to command, direct, or regulate itself or another system.
Control Systems
Control Systems
Input
• The input is the stimulus, excitation or command applied to a control system.
• Typically from external energy source, usually in order to produce a specified response from the control system.
Control Systems
Output
• The output is the actual response obtained from a control system.
• It may or may not be equal to specified response implied by the input.
Control Systems
References for reading
1. R.C. Dorf and R.H. Bishop, Modern Control Systems,10th Edition, Prentice Hall, 2008,Chapter 1.1 - 1.10
2. J.J. DiStefano, A. R. Stubberud, I. J. Williams, Feeedback and Control Systems, Schaum's Outline Series, McGraw-Hill, Inc., 1990Chapters 1, 2
Control Systems
History of Automatic Control
Control Systems
Prior to World War II
A main impetus for the use of feedback in the United States was the development of the telephone system and electronic feedback amplifiers by Bode, Nyquist, and Black at Bell Telephone Laboratories.
Control Systems
Prior to World War II
The Russian theory tended to utilize a time-domain formulation using differential equations.
Control Systems
World War II
Design and construct:
• automatic airplane pilots,
• gun-positioning systems,
• radar antenna control systems.
Control Systems
Sputnik and space age
The time-domain methods developed by Liapunov, Minorsky, and others have met with great interest in the last two decades.
Control Systems
Resent time
Recent theories of optimal control developed by L.S. Pontryagin in the former Soviet Union and R. Bellman in the United States, and studies of robust systems, have contributed to the interest in time-domain methods.
Control Systems
Terms and Concepts
Control Systems
Control system
• A control system is an interconnection of components forming a system configuration that will provide a desired system response.
Control Systems
Two Types of Control Systems
• Open Loop– No feedback– Difficult to control
output with accuracy
• Closed Loop– Must have feedback– Must have sensor on
output– Almost always negative
feedback
Control Systems
Open-loop control
An open-loop control system utilizes an actuating device to control the process directly without using feedback.
A common example of an open-loop control system is an electric toaster in the kitchen.
Control Systems
Control Systems
Closed-loop control
A closed-loop control system uses a measurement of the output and feedback of this signal to compare it with the desired output.
Control Systems
Control Systems
A person steering an automobile by looking at the auto’s location on the road and making the appropriate adjustments.
Control Systems
Control Systems
Manual control system
Intelligent Control
Goal: Regulate the level of fluid by adjusting the output valve.
The input is a reference level of fluid and is memorized by operator.The power amplifier is the operator.The sensor is visual.Operator compares the actual level with the desired level and opens or closes the valve ( actuator).
26
The level of fluid in a tank control.
27Intelligent Control
Multivariable control system
Control Systems
Control Systems
Control Systems
Control system of the national income.
Control Systems
A robot is a computer-controlledmachine.
Industrial robotics is a particular field of automation in which the robot is designed to substitute for human labor.
The Honda P3 humanoid robot.
Control Systems
• Automation - The control of a process by automatic means.
• Closed-loop feedback control system - A system that uses a measurement of the output and compares it with the desired output.
Control Systems
Design-The process of conceiving or inventing the forms, parts, and details of a system to achieve a specified purpose.
Feedback signal - A measure of the output of the system used for feedback to control the system.
Multivariable control system - A system with more than one input variable or more than one output variable.
Control Systems
Negative feedback -The output signal is fed back so that it subtracts from the input signal.
Open-loop control system - A system that utilizes a device to control the process without using feedback.
Optimization -The adjustment of the parameters to achieve the most favorable or advantageous design.
Control Systems
Positive feedback -The output signal is fed back so that it adds to the input signal.
Process -The device, plant, or system under control.
Productivity -The ratio of physical output to physical input of an industrial process.
Control Systems
Robot - Programmable computers integrated with a manipulator.
Synthesis - The combining of separate elements or devices to form a coherent whole.
System - An interconnection of elements and devices for a desired purpose.
Control Systems
The Control System Design Process
• Design is the process of conceiving or inventing the forms, parts, and details of a system to achieve a specified purpose.
Engineering design
Control Systems
Engineering design
Trade-off
The result of making a judgment about how to compromise between conflicting criteria.
Control Systems
Control system engineers are concerned with understanding and controlling segments of their environment, often called systems, to provide useful economic products.
Control Systems
Goals
Twin goals of understanding and controlling are complementary because effective systems control requires that the systems be understood and modeled.
Control Systems
Control engineering
Control engineering is based on the foundations of feedback theory and linear system analysis, and it integrates the concepts of network theory and communication theory.
Control Systems
Given a process, how to design a feedback control system?
Three steps:
• Modeling. Obtain mathematical description of the systems.
• Analysis. Analyze the properties of the system.
• Design. Given a plant, design a controller based on performance specifications.
The course spans each of these steps in that sequence.
Control Systems
The basis for analysis of a system is the foundation provided by linear system theory, which assumes a cause-effect relationship for the components of a system.
Control Systems
Control Systems
Design examples
Rotating disk speed control
Control Systems
Step 1. Control goal
• Design a system that will held a rotating disk at a constant speed. Ensure that
the actual speed of rotation is within a specified percentage of desired speed.
Control Systems
Step 2. Variable to be controlled
• Speed of rotation disc
Control Systems
Step 3. Control design specification
• Design a system that will ensure that
the actual speed of rotation is within a specified percentage of desired speed.
Control Systems
Step 4 Preliminary system configuration
Control Systems
Step 4 Preliminary system configuration
Control Systems
With precision components, we could expect
to reduce the error of the feedback system to
one-hundredth of error of the open-loop system.
Control Systems
Insulin delivery system
The blood glucose and insulin concentrations for a healthy person.
Control Systems
Step 1. Control goal
• Design a system to regulate the blood sugar concentration of a diabetic by controlled dispensing of insulin.
Control Systems
Step 2. Variable to be controlled
• Blood glucose concentration
Control Systems
Step 3. Control design specification
• Provide a blood glucose level for the diabetic that closely approximates the glucose level of a healthy person.
Control Systems
Step 4 Preliminary system configurations
Control Systems
A drug-delivery system implanted in the body
uses an open-loop system, since miniaturized
glucose sensors are not yet available.
Control Systems
Disk drive read system
Control Systems
Control Systems
Step 1. Control goal
• Design a system that will held the position the reader head to read the data stored on a track on the disk.
Control Systems
Step 2. Variable to be controlled
• Position of the reader head
Control Systems
Step 3. Control design specification
• Design a system that will ensure that the head :
- “flies” above the disk at a distance of less than 100 nm,
- with the position accuracy is 1 m,
- with speed from track to track 50 ms
Control Systems
Step 4 Preliminary system configuration
Control Systems
E 1: Controlling the position of a missile launcher from a remote location
The input is the desired angular position of the missile launcher, The control system consists:of potentiometer, power amplifier, motor, gearing between the motor and the missile launcher,missile launcher.
Control Systems
A position open loop control
The input is the desired angular position of the missile launcher, and the control system consists of potentiometer, power amplifier, motor, gearing between the motor and missile launcher, and missile launcher.
Control Systems
A position closed loop control
Should an error exists, it is amplified and applied to a motor drive which adjusts the output-shaft position until it agrees with the input-shaft position, and the error is zero.
Control Systems
P1.2 Manual control system
Control Systems
Fluid-flow control
• P1.2 In the past, control systems used a human operator as part of a closed-loop control system. Sketch the block diagram of the valve control system shown in Fig. P1.2
Control Systems
P1.3 Chemical composition control
• Complete the control feedback loop, and sketch a block diagram describing the operation of the control loop.
Control Systems
Control Systems
P1.8 Student-teacher learning process
• Construct a feedback model of the learning process and identify each block of the system.
Control Systems
Inverted pendulum control
• E1.11 Sketch the block diagram of a feedback control system. Identify the process, sensor, actuator, and controller.
The objective is keep the pendulum in the upright position ( = 0), in the presence of disturbances.
Control Systems
Control Systems
Applications
Control engineering is not limited to any engineering discipline but is equally applicable to:
aeronautical,
chemical,
mechanical,
computer science and engineering ,
civil engineering,
electrical engineering.
Control Systems
Mechatronic systems
Control Systems
Questions ?
Control Systems
Control Systems
Control Systems
Control Systems
Control Systems
The design of control systems is a specific example of engineering design. The goal of control engineering design is to obtain the configuration, specifications, and identification of the key parameters of a proposed system to meet an actual need.
Control Systems
The design process consists of seven main building blocks, which are arrange into three groups:1.Establishment of goals and variables to be controlled, and definition of specifications against which to measure performance2.System definition and modeling3.Control system design and integrated system simulation and analysis
Control Systems
Design 1
Control Systems
Design 2
Control Systems
Design 3
Control Systems
Open-loop and closed-loop systems
Related Documents
