Bài giảng Cơ sở tự động - Chương 1: Giới thiệu về hệ thống điều khiển tự động - Nguyễn Đức Hoàng

CƠ SỞ TỰ ĐỘNG 
Giảng viên: Nguyễn Đức Hoàng 
Bộ môn Điều Khiển Tự Động 
Khoa Điện – Điện Tử 
Đại Học Bách Khoa Tp.HCM 
Email: ndhoang@hcmut.edu.vn 
MÔN HỌC 
Nội dung môn học (10 chương) (14 tuần = 42 tiết LT + 14 tiết BT) 
Chương 1: Giới thiệu về hệ thống điều khiển tự động 
Chương 2: Mô hình toán học hệ thống liên tục 
Chương 3: Đặc tính động học 
Chương 4: Khảo sát tính ổn định của hệ thống 
Chương 5: Chất lượng hệ thống điều khiển 
Chương 6: Thiết kế hệ thống tuyến tính liên tục 
Chương 7: Mô hình toán học hệ rời rạc 
Chương 8: Phân tích hệ rời rạc 
Chương 9: Thiết kế hệ rời rạc 
Chương 10: Ứng dụng 
Tài liệu tham khảo 
Giáo trình: Lý thuyết điều khiển tự động 
Nguyễn Thị Phương Hà – Huỳnh Thái Hoàng 
NXB Đại Học Quốc Gia TpHCM 
Bài tập: Bài tập điểu khiển tự động 
Nguyễn Thị Phương Hà 
Tài liệu: 
Automatic Control System 
Modern Control System Theory and Design 
Đánh giá 
Thi giữa kỳ 	: 20 % 
Thi cuối kỳ 	: 60% 
Bài tập	: 20% bao gồm: 
	 + về nhà có kết hợp mô phỏng Matlab 
	 + trên lớp : gọi lên bảng làm ( mỗi lần không làm được -1đ vào điểm thi GK, -0.5đ vào điểm thi CK ) 
GIỚI THIỆU VỀ HỆ THỐNG 
ĐIỀU KHIỂN TỰ ĐỘNG 
CHƯƠNG 1 
Control Systems 
6 
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 
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. 
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. 
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. 
	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 time-domain formulation using differential 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 
Open Loop 
No feedback 
Difficult to control output with accuracy 
Closed Loop 
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). 
29 
The level of fluid in a tank control. 
30 
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 
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 
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 
Control Systems 
Inverted pendulum control