Transcript The Principle of Automatic Control 自动控制原理

Significance
（课程意义）
 Control engineering is an exciting and challenging field.
 It is a multidisciplinary subject, and a core course in the
engineering curriculum.
 It is widely applied to the field of industry and
agriculture ,even to the sociological, biological,
ecological and economic systems.
 It is especially used in high-technology areas such as
spacecraft control system.
Bilingual Course
（双语课程）
 Language: Both English and Chinese
 Emphasis :Content,such as basic concept
and basic principle of automatic control
 Grasp or enrich major terminology
 Improve the ability to read speciality
references or materials
The Excitement of Control Engineering
 Control Engineering is present in virtually
all modern engineering systems
 Control is a key technology with respect to:
• increased productivity
• improved performance or product quality
• waste and emission minimization
• environmental protection
• higher safety
Control is a multidisciplinary subject
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sensors
actuators
communications
computing
architectures and interfacing
algorithms
Control design aims to achieve a desired level
of performance in the face of disturbances and
uncertainty
Ch1 Introduction to Control system
 Basic Concept of Control System
 History and Development of Automatic Control
 The Principle of Feedback Control
 Basic Forms of Control System
 Basic Components of Closed-loop system
 Basic Requirements (Performance)
 Classification of Control System
 Examples of Modern Control System
 Simulation with MATLAB(CSCAD)
1.1 Basic Concept of Control System
 A Control System is an interconnection of
components forming a system configuration
that will provide a desired system response.
 The basis for system analysis and design is
linear system theory.
 Process or plant to be controlled can be
represented by cause-effect relationship.
input
process
output
• Open-loop Control System
An open-loop Control System utilizes an actuating
device to control the process directly without using
feedback. as shown in Fig.1.2(page 2)
• Closed-loop Control System
A closed-loop control system uses a measurement of
the output and feedback of this signal to compare it
with the desired output(reference or command). as
shown in Fig.1.3(page 3)
1.2 History and Development
of Automatic Control
 fascinating history date back to 300 B.C,
such as float regulator mechanism and
water clock
 James Watt’s flyball governor in1769
 J.C. Maxwell formulates a mathematical
model for a governor control
 Henry Ford’ s assembly line for automobile
production in 1913
 H.W.Bode analyzes feedback amplifiers at
Bell Telephone Lab in 1927
 auto-pilots, gun-positioning systems,radar
antenna control system and other military
systems in World War II
 State-variable models and optimal control
developed in 1960’s-1970’s (space age)
 Robust control widely studied in 1980’s
 Intelligent control etc.
Development of Control Theory
Cybernetics (1948)
control
classic control
large-scale system control
modern
robust
and intelligent control
•see some other materials:control_history
1.3 The Principle of Feedback Control
 Feedback concept is the foundation for
control system analysis and design
 Feedback control system is to control the
process by using the difference between the
output and reference input
 Negative feedback (refer to P7)
 Positive feedback
1.4 Basic Forms of Control System
 open-loop control system
 closed-loop control system
 composite control system
Feedback control+ feedforward control
1.5 Basic Components of Closed-loop system
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Signal generator
measurement elements or sensors
comparison elements
amplifier elements
actuator
controller or compensator
1.6 Basic Requirements (Performance)
 Stability
 quickness or rapidness
 Accuracy
1.7 Classification of Control System
 Open-loop and closed-loop system
 Linear and nonlinear system
 Time-variant and time-invariant system
 continuous-time and discrete-time system
1.8 Examples of Modern Control System
 Speed control system
 auto-pilot system of aircraft
 gun-positioning serve system
 process control system
 other examples:(refer to P9-15)
1.9 Simulation with MATLAB(CSCAD)
控制系统计算机辅助设计（ComputerAided Control System Design, 简称为
CACSD）。随着控制理论的迅速发展，控制性
能的要求越来越高，控制对象和算法越复杂，
对其进行分析和设计就越困难。传统的计算
方法和运算工具难以达到预期的效果，加之
近30年计算机技术的飞速发展，就产生了
CACSD技术。
系统仿真：广义上讲，为了系统的分析和设计，
首先建立系统的模型，然后在模型上进行实验这
一过程就称为系统仿真。根据模型的种类不同，
系统仿真可分为三种：
物理仿真（实物，如飞机风洞实验）真实直
观；投资大、周期长，试验受限制
数字仿真（基于系统数学模型的仿真）经济
、方便、灵活；真实性要依赖模型
物理---数学仿真（半实物仿真，如飞机、导
弹等运动体的转台实验）
本课程涉及的是数字仿真（或称计算机仿真），仿真应包含
两个过程：建立模型及模型试验。计算机仿真包含三要素：系
统、模型与计算机；与之相联系的三个基本活动：模型建立、
仿真模型建立及仿真试验。它们之间的关系可由图表示：
系 统
模型建立
仿真实验
仿真模型建立
模 型
计算机
图1 计算机仿真的基本要素与基本活动
•系统仿真语言MATLAB
MATLAB软件环境是美国New Mexico大学
的Cleve Moler博士首创的，全名为: MATrix
LABoratory（矩阵实验室）。它是由20世纪
七八十年代流行的LINPACK（线性代数计算）
和ESPACK（特征值计算）软件包基础上发展
而来。最早的MATLAB版本在DOS环境下运行，
使用不够方便。现在的MATLAB6.0在Windows
环境下运行，充分利用了Windows环境的交互
性、多任务和图形功能，建立了用C语言编写
的一种专用语言。
MATLAB语言不仅使矩阵运算、数值运算变得极
为简单，而且还配备了各种功能强大的专用工具箱，
如控制系统工具箱(Control systems toolbox)，
此外还有：
系统辨识工具箱(System identification
toolbox)，
信号处理工具箱(Signal processing toolbox )，
鲁棒控制工具箱(Robust control toolbox) ，
模糊控制工具箱(Fuzzy control toolbox) ，
神经网络工具箱(Neural networks toolbox) 、
小波分析工具箱(Wavelet toolbox)等。
Summary
 Open-loop and closed-loop control system
 feedback mechanism
 control system design process
Two tasks: analysis and design
Assignment
(课后作业）
 Review Ch1 (P1-24)
 P1.2
 P1.11