机械控制理论Chap1

1、School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 1Fundamentals of Control TheorySchool of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 2Bilingual CourseCourse: Fundamentals of Mechanical Con

2、trol Theory机械机械控制理论基础控制理论基础Teaching Material: Linear Control System Analysis and Design Fourth Edition 线性控制系统分析与设计线性控制系统分析与设计 第第4版版School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 3References 1. 杨叔子，杨叔子，机械工程控制基础机械工程控制基础，第四版，第四版， 华中理工大学出版社华中理工

3、大学出版社 2. 绪方盛彦绪方盛彦, 现代控制理论现代控制理论, 科学出版社科学出版社 3. 李友善李友善, 自动控制原理自动控制原理(上册上册) , 国防工业出版社国防工业出版社 4. 张伯鹏张伯鹏, 控制工程基础控制工程基础, 机械工业出版社机械工业出版社 5. 阳含和阳含和, 机械控制工程机械控制工程(上册上册) , 机械工业出版社机械工业出版社 6. 姚伯威姚伯威, 控制工程基础控制工程基础, 电子科技大学出版社电子科技大学出版社 7. 薛定宇薛定宇, 控制系统计算机辅助设计控制系统计算机辅助设计MATLAB语言及语言及 应用应用, 清华大学出版社清华大学出版社 School of M

4、echanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 4Learning requirement 1. All exercises and experiment reports must be done in English, and all questions must be answered in English. 2. must be present (must not be absent) 3. taking notes：Dont merely co

5、py the blackboard, trying to write down what you consider is important. 4. preview 5. reviewSchool of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 5Learning requirement 6. do exercises and experiments independently 7. summarizing, concluding 8. Don

6、t read the book word by word, the emphases should be put on the understanding the concepts, terminologies as well as their logic relations 9. Daring to put forward questions 10. If you have any question, Please contact me.School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Contro

7、l Theory Chap 1 INTRODUCTION 6Final examination result 1. Daily behaves: 30%. Including: present, exercises, experiments. 2. Final examination: 70%. School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 7 Chap 1 INTRODUCTION 1.1 INTRODUCTION 1.2 I

8、NTRODUCTION TO CONTROL SYSTEMS 1.3 DEFINITIONS 1.4 HISTORICAL BACKGROUND 1.5 DIGITAL CONTROL DEVELOPMENT 1.6 MATHEMATICAL BACKGROUND1.7 GENERAL NATURE OF THE ENGINEERING CONTROL PROBLEM1.8 COMPUTER LITERACY1.9 OUTLINE OF TEXT School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Co

9、ntrol Theory Chap 1 INTRODUCTION 81.1 Introduction With the rapidly development of the modern science and technologies, man created many miracles. One of them is the invention of automatic control equipments. Today, we cant live on without the help of these auto-machines. Automatic control systems p

10、ermeate (渗透) life in all advanced societies today. produce goods required by an increasing world population travel to the moon and explore outer space space vehicles, the space shuttle, space stations reconfigurable flight control systems School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Funda

11、mentals of Control Theory Chap 1 INTRODUCTION 91.2 Introduction to control systems There are many equipments with control systems in our daily lives, such as:refrigeratorsrobotsair-conditionerauto-washerselevatorspilotless aircraftmen School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundament

12、als of Control Theory Chap 1 INTRODUCTION 10Example: toaster input: timeroutput: degree of darkness and crispness The output quantity has no influence on the input quantity, there is no feedback in this system School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Cha

13、p 1 INTRODUCTION 11Example: DC shunt motor input: armature voltage output: speed of the shaft Voltage source for field Voltage source for armature DC: Direct CurrentAC: Alternating CurrentSchool of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 12ope

14、n-loop control systems: Systems in which the output quantity has no effect upon the input quantity command input: desired darkness of the toast or the desired speed of the motor functional block diagram: reference-selector block : selection of the value of time on the toaster timer or the value of v

15、oltage applied to the motor armature reference input : output of the reference-selector block dynamic unit : the unit which the reference input is applied to desired output : output of the dynamic unit School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTR

16、ODUCTION 13closed-loop control systems: Systems in which the output has a direct effect upon the input quantity functional block diagram of a single-input single-output (SISO): characteristic : the output is fed back and is compared with the input comparison unit : performs comparison between the re

17、ference input and the feedback signal and results in an actuating signal School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 14Example: home heating control system A bimetallic coil in the thermostat is affected by both the actual room temperatu

18、re (output) and the reference-selector setting. Another example: Refer to Ch. material P1-14 School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 151.3 Definitions From the preceding discussion the following definitions are evolved, based in part

19、 on the standards of the IEEE, and are used in this text. IEEE: Institute for Electrical and Electronic Engineers 电气和电子工程师学会美 System. A combination of components that act together to perform a function not possible with any of the individual parts. Command input. The motivating input signal to the s

20、ystem, which is independent of the output of the system and exercises complete control over it (if the system is completely controllable). School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 161.3 Definitions Reference selector(reference input e

21、lement). The unit that establishes the value of the reference input. The reference selector is calibrated in terms of the desired value of the system output. Reference input. The reference signal produced by the reference selector, i.e., the command expressed in a form directly usable by the system.

22、 It is the actual signal input to the control system. Disturbance input. A disturbance input signal to the system that has an unwanted effect on the system output. School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 171.3 Definitions Forward ele

23、ment (system dynamics). The unit that reacts to an actuating signal to produce a desired output. This unit does the work of controlling the output and thus may be a power amplifier. Output (controlled variable). The quantity that must be maintained at a prescribed value, i.e., it must follow the com

24、mand input without responding to disturbance inputs. Open-loop control system. A system in which the output has no effect upon the input signal.School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 181.3 Definitions Feedback element. The unit that

25、 provides the means for feeding back the output quantity, or a function of the output, in order to compare it with the reference input. Actuating signal. The signal that is the difference between the reference input and the feedback signal. It is the input to the control unit that causes the output

26、to have the desired value. Closed-loop control system . A system in which the output has an effect upon the input quantity in such a manner as to maintain the desired output value. School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 191.3 Defini

27、tions The fundamental difference between the open- and closed-loop systems is the feedback action. School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 201.3 Definitions Servomechanism (often abbreviated as servo). The term is often used to refer

28、 to a mechanical system in which the steady-state error is zero for a constant input signal. Sometimes, by generalization, it is used to refer to any feedback control system. Regulator. This term is used to refer to systems in which there is a constant steady-state output for a constant signal. The

29、name is derived from the early speed and voltage controls, called speed and voltage regulators. School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 211.4 Historical background A pictorial demonstration of an automobile as a feedback control syst

30、em School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 221.4 Historical background Heroes device for opening temple doors School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 231.4 Historical

31、 background James Watts flyball governor load disturbance M rotated speed n centrifugal framework expansion sliding cover of comparing framework valve (through the level of the transition framework) steam quantity Q n (Ch1-9)School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Con

32、trol Theory Chap 1 INTRODUCTION 241.4 Historical backgroundAntiaircraft radar-tracking control system (Ch1-16)School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 251.4 Historical background1868: J C Maxwell, On speed regulating machine, Proceedi

33、ng of the Royal Society of Landon, Vol. 161884: E J Routh, Stability criterion of linear system1923: Heaviside, arithmetic operators method1930s: H Nyquist, Nyquist Stability criterion H W Bode, negative feedback amplifiers 1945: publication of servomechanism1948: publication of Theory of controls 1

34、950: W R Evans, Root-Locus methodSchool of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 261.4 Historical background conventional control theory: developed through the late 1950s. Which is effectively applied to many control-design problems, especia

35、lly to SISO systems. modem control theory: developed for the design of more complicated systems and for multiple-input multiple-output (MIMO) systems. The development of control concepts in the engineering field has been extended to the realm of human and biomedical engineering. School of Mechanical

36、 Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 271.5 Digital control development aerospace vehicles: 宇航飞行器 control surfaces: 操纵面 stability augmentation system: 增稳系统, SAS control stick: 驾驶杆 airborne digital processors: 机载数字处理器 School of Mechanical Engineering湖南

37、工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 281.6 Mathematical Background differential equations: a classical means, used in the solution of control systems in the early studies. The approach is tedious and does not readily indicate what changes should be made to improve

38、 system performance. Laplace transform: transforms differential equations to algebraic equations in order to simplify the above method. Nyquists method: deals with the application of steady-state frequency-response techniques to feedback amplifier design, extended by Black, Bode, Hall, Harris, etc.

39、root-locus theory: presented by Evans, permits the graphical evaluation of both the time and the frequency response.School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 291.6 Mathematical Background Mathematical models: a set of mathematical equa

40、tions describing a physical system. Once the Mathematical models are set up, the subsequent method of analysis is independent of the nature of the physical system; i.e., it does not matter whether the system is electrical, mechanical, or something else. This technique helps the designer to spot simi

41、larities based upon previous experience. School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 301.6 Mathematical Background No single design method is intended to be used to the exclusion of the others. Depending upon the known factors and the si

42、mplicity or complexity of a control-system problem, a designer may use one method exclusively or a combination of methods. With experience in the design of feedback control systems comes the ability to use the advantages of each method. School of Mechanical Engineering湖南工业大学机械工程学院湖南工业大学机械工程学院Fundamentals of Control Theory Chap 1 INTRODUCTION 311.7 General nature of the engineering control problem In general, a control problem can be divided into the following steps: 1.