GIỚI THIỆU về hệ THỐNG điều KHIỂN tự ĐỘNG (cơ sở tự ĐỘNG SLIDE)

• The output is the actual response obtained from a control system.. Open-loop controlAn open-loop control system utilizes an actuating device to control the process directly without us

GIỚI THIỆU VỀ HỆ THỐNG

ĐIỀU KHIỂN TỰ ĐỘNG

CHƯƠNG 1

Control Systems 2

1769

• James Watt’s steam engine and governor developed

The Watt steam engine is often used to mark the

beginning of the Industrial Revolution in Great

Britain During the Industrial Revolution, great

strides were made in the development of

mechanization, a technology preceding automation.

• Control is a sequence of decisions aimed at the

attainment of specified objectives in an

environment of uncertainty and presence of

disturbances.

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.

• 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.

• 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.

History of Automatic Control

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.

Prior to World War II

The Russian theory tended to utilize a domain formulation using differential

time-equations

World War II

Design and construct:

• automatic airplane pilots,

• gun-positioning systems,

• radar antenna 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.

Recent 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.

Terms and Concepts

Two Types of Control Systems

– Must have feedback

– Must have sensor on

output

– Almost always negative

feedback

Open-loop and closed-loop 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.

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.

A person steering an automobile by looking at

the auto’s location on the road and making the appropriate adjustments.

Control Systems

Manual control system

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).

25

The level of fluid in a tank control

26

Multivariable control system

A robot is a computer-controlled machine.

Industrial robotics is a particular field of automation in which the robot is designed to substitute for human labor

The Honda P3 humanoid robot.

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

Engineering design

Trade-off The result of making a judgment about how to compromise between conflicting criteria.

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.

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

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

Disk drive read system

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 speed from track to track 50 ms

Control Systems

Step 4 Preliminary system configuration

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

P1.8 Student-teacher learning process

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

Inverted pendulum control