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1、自动化专业英语教程,教学课件,July 28,2007,P2U5A Introduction to Modern Control Theory 第二部分第五单元课文A 现代控制理论简介,A 现代控制理论简介 1.课文内容简介：主要介绍现代控制理论中现代控制理论产生的背景与原因，与传统控制理论之间的差别及其优点，状态的概念等内容。2.温习现代控制理论中绪论的内容。3.生词与短语constraint n.强迫，约束multiply v.加倍，倍增stimulus n.刺激，鼓励optimal control 最优控制dominate v.支配，使服从package n.包very large sc
2、ale integrated circuits(VLSI)超大规模集成电路,P2U5A Introduction to Modern Control Theory 第二部分第五单元课文A 现代控制理论简介,numerical adj.数字的matrix n.矩阵 pl.matriceslinear vector space 线性矢量空间ad hoc 尤其，特定地alleviate v.减轻，缓和arbitrary adj.任意的formulation n.公式化（表达）implementation n.实现，履行attain v.达到，实现constitute v.构造，组织insofar a
3、s 到这样的程度，在范围内continuum n.连续gross national product 国民生产总值trade deficit 贸易赤字scalar adj.数量的，标量的；n.数量，标量,P2U5A Introduction to Modern Control Theory 第二部分第五单元课文A 现代控制理论简介,n-dimensional adj.n维的circumstance n.状况，环境4.难句翻译1 The transition from simple approximate models,which are easy to work with,to more rea
4、listic models produces two effects.从易于处理的简单近似模型到实际一些的模型的转换存在两方面问题。2 It provides an ideal formulation for computer implementation and is responsible for much of the progress in optimization theory.它（现代控制理论）为计算机实现提供了理想的公式化方法，并对最优化理论的发展起了重要作用。,P2U5A Introduction to Modern Control Theory 第二部分第五单元课文A 现代控
5、制理论简介,3 As far as the state at t1 is concerned,it makes no difference how the initial state was attained.就t1时刻的状态而言，它与初始状态是怎样实现的无关。as far asbe concerned：就而言；make no difference：无论都没有区别（没关系）4 Thus the state at t0 constitutes a complete history of the system behavior prior to t0,insofar as that history
6、 affects future behavior.因此，t0时刻的状态构成了t0以前系统活动状态的历史，这个历史状态在一定范围内影响（系统）未来的行为。,A Introduction to Modern Control Theory,Classical control theory is based on inputoutput relationships，principally the transfer function.When differential equations are encountered,they are linearized and subjected to whate
7、ver constraints are necessary to establish useful input-output relationshipModem control theory,on the other hand,is based on direct use of the differential equations themselves.Although its technique are powerful and relatively simple,classical control theory does have limitations and shortcomings
8、that multiply as plants and control systems become more complex-thus the advent of modern control theory.,Several factors provided the stimulus for the development of modem control theory.(1)The necessity of dealing with more realistic models of systems(2)The shift in emphasis towards optimal contro
9、l and optimal system design(3)The continuing developments in digital computer technology(4)The shortcomings of previous approaches，(5)A recognition of the applicability of well-known methods in other fields of knowledge.,The transition from simple approximate models,which are easy to work with,to mo
10、re realistic models produces two effects.First,a larger number of variables must be included in the modelSecond,a more realistic model is more likely to contain nonlinearities and time-varying parameters.Previously ignored aspects of the system，such as interactions with and feedback through the envi
11、ronment，are more likely to be included,With an advancing technological society,there is a trend towards more ambitious goalsThis also means dealing with complex systems with a larger number of interacting componentsThe need for greater accuracy and efficiency has changed the emphasis on control syst
12、em performanceThe classical specifications in terms of percent overshoot，settling time，bandwidth，etc，have in many cases given way to optimal criteria such as minimum energy，minimum cost，and minimum time operationOptimization of these criteria makes it even more difficult to avoid dealing with unplea
13、sant nonlinearitiesOptimal control theory often dictates that nonlinear time-varying control laws be used，even if the basic system is linear and time-invariant,The continuing advances in computer technology have had important effects on the controls field.The fast processing ability and large memory
14、 capacity of digital computers make it possible to solve practical problems with complex high-order differential equationsClassical control theory was dominated by graphical methods because at the time that was the only way to solve certain problemsNow every control designer has easy access to power
15、ful computer packages for systems analysis and designAlthough a computer can be used to carry out the classical transform-inverse transform methods,it is usually more efficient to be find(calculate)the numerical solutions of a differential equation directly,Modem control theory is well suited to the
16、 above trends because its time domain techniques and its mathematical language(matrices，linear vector spaces，etc.)are ideal when dealing with a computer.Computers are a major reason for the existence of state variable methods,With the development of very large scale integrated circuits(VLSI)，the cos
17、t，size，and reliability of microcomputers have made it possible to use them routinely in many systemsComputers are now so commonly used as just another component in the control system,Most classical control techniques were developed for linear constant coefficient system with one input and one output
18、(perhaps a few inputs and outputs).The language of classical techniques is the Laplace or z-transform and transfer functionsWhen nonlinearities and time variations are present，the very basis for these classical techniques is removed.Some successful techniques such as phase-plane methods，describing f
19、unctions，and other ad hoc methods,have been developed to alleviate this shortcoming.However，the greatest success has been limited to low-order systems.The state variable approach of modern control theory provides a uniform and powerful method of representing systems of arbitrary order，linear or nonl
20、inear，with time-varying or constant coefficientsIt provides an ideal formulation for computer implementation and is responsible for much of the progress in optimization theory.,The Concept of State,The concept of state occupies a central position in modern control theoryHowever，it appears in many ot
21、her technical and nontechnical contexts as well.In thermodynamics the equations of state are prominently used.Binary sequential networks are normally analyzed in terms of their states.In everyday 1ife，monthly financial statements are commonplace.The Presidents State of the Union message is another f
22、amiliar example,In all of these examples the concept of state is essentially the same.It is a complete summary of the status of the system at a particular point in timeKnowledge of the state at some initial time t0,plus knowledge of the system inputs after t0，allows the determination of the state at
23、 a later time tl.As far as the state at tl is concerned，it makes no difference how the initial state was attained.Thus the state at t0 constitutes a complete history of the system behavior prior to t0，insofar as that history affects future behavior.Knowledge of the present state allows a sharp separ
24、ation between the past and the future.,At any fixed time the state of a system can be described by the values of a set of variables xi,called state variables.One of the state variables of a thermodynamic system is temperature and its value can range over the continuum of real numbers RIn a binary ne
25、twork state variables can take on only two discrete values，0 or 1Note that the state of your checking account at the end of the month can be represented by a single number,the balanceThe state of the Union can be represented by such things as gross national product，percent unemployment，the balance o
26、f trade deficit,ect.For the systems considered in this article the state variables may take on any scalar value，real or complex.That is,xi C.Although some systems require an infinite number of state variables,only systems which can be described by a finite number n of state variables will be conside
27、red here.Then the state can be represented by an n component state vector x=xl x2XnT.It belongs to an n-dimensional vector space defined over the field C,For Continuous-time systems，the state is defined for all times in some interval.For example,a continually varying temperature or voltageDiscrete-t
28、ime systems have their state defined only at discrete times，as with the monthly financial statement or the annual State of the Union message.Continuous-time and discrete-time systems can be discussed simultaneously by defining the times of interest as TFor continuous-time systems T consists of the s
29、et of all real numbers tt0,t1.For discrete-time systems T consists of a discrete set of timest0，t1,tk.In either case the initial time could be-and the final time could be in some circumstances.,The state vector X(t)is defined only for those tTAt any given t，it is simply an ordered set of n numbersHo
30、wever，the character of a system could change with time，causing the number of required state variables(and not just the values)to changeIf the dimension of the state space varies with time,the notation t could be usedIt is assumed here that is the same n-dimensional state space at all tT.,P2U5A Intro
31、duction to Modern Control Theory 第二部分第五单元课文A 现代控制理论简介,5.参考译文A 现代控制理论简介引言 经典控制理论以输入输出关系主要是传递函数为基础。当遇到微分方程时，它们必须是线性的、包含（服从）所有约束,P2U5A Introduction to Modern Control Theory 第二部分第五单元课文A 现代控制理论简介,条件，才能建立有用的输入输出关系。然而，现代控制理论是基于微分方程本身的直接使用。尽管经典控制理论的技术是强有力的，而且相对简单，但它的确存在一些局限和缺点，这些缺点会随着被控对象和控制系统的复杂化而加剧，这正是现代控
32、制理论出现的原因。几种因素为现代控制理论的发展提供了动力：1.处理更为实际的系统模型的需要。2.侧重点移向最优控制和最优系统设计。3.计算机技术的持续发展。4.先前方法的缺陷。5.对其他知识领域已知方法的应用能力的认识。从易于处理的简单近似模型到实际一些的模型的转换产生了两种作用（存在着两个方面的问题）。第一，大量的变量必须包含在模型中。第二，更实际的模型更容易包含非线性和时变参数。以前系统被忽视的方面，如与周围环境的相互作用和通过环境的反馈往往被包含进来。,P2U5A Introduction to Modern Control Theory 第二部分第五单元课文A 现代控制理论简介,技术社
33、会的发展正朝向更加雄必勃勃的目标前进。这也意味着要处理有着大量相互作用部件的复杂系统。对更高精度和效率的要求已经改变了控制系统性能的重点。以超调量、调节时间、带宽等词来描述的经典的技术要求，在很多情况中已让位于最优判据如最小能量、最小代价、最小时间。最优化这些判据难以避开所不希望的非线性。最优控制理论常常要求使用非线性、时变的控制规律，即使基本系统是线性和时不变的。计算机技术的不断发展在控制领域产生了重要的影响，数字计算机快速的处理能力和巨大的存储容量，使得求解带有复杂高阶微分方程的实际问题成为可能。经典控制理论主要是（由.支配）图形方式，因为在那个时代这是解决特定问题的唯一方法。现在每一位控
34、制设计者都可以轻松地使用功能强大的计算机（软件）包进行系统分析和设计。尽管计算机可以用于实现经典的变换反变换方法，但用它来直接求解（计算）,P2U5A Introduction to Modern Control Theory 第二部分第五单元课文A 现代控制理论简介,微分方程的数值解往往效率高。随着超大规模集成电路的发展，微型计算机的价格、尺寸和可靠性使它们能够常规地用于许多系统中。计算机现在就像控制系统的一个部件一样被很平常地使用。现代控制理论正好适合上述的趋势，因为它的时域技术和它的数学语言（矩阵、线性矢量空间等等）用计算机处理时非常理想。计算机是状态变量方法存在的一个主要原因。大多数经
35、典控制技术是面向单输入单输出（也许有几个输入输出）的线性常系数系统。经典技术的语言是拉普拉斯或变换和传递函数，当存在非线性时变的时候，经典技术就失去了正确的基础。一些成功的技术如相平面法、描述函数和其他特定方法被开发出来以缓解这个缺点。然而，最大的成功被限制在低阶系统中。现代控制理论的状态变量方法提供了一个统一的、强有力的、表达任意阶的线性或非线性的、时变或常系数的系统的方法。它为计算机实现提供了理想的公式化表达，也导致了在最优化理论方面的一些进步。,P2U5A Introduction to Modern Control Theory 第二部分第五单元课文A 现代控制理论简介,状态的概念 在
36、现代控制理论中状态的概念占据了中心地位，然而，它也出现在一些其他的技术或非技术的文章上下文中。在热力学中，“状态（state)”方程被突出地使用，二进制时序电路一般根据它们的“状态（state)”来分析，在日常生活中每月的财政“报告（statement)”是很平常的，联邦总统报告的消息是另一个例子。在所有这些例子中，“状态（state)”的概念从本质上是相似的，它是系统状况在特定时刻完整的总结。在某一初始时刻t0的状态（情况）加上t0时刻以后的系统输入情况，可以确定在后来的t1时刻的状态。就t1时刻的状态而言，它与初始状态是怎样实现的无关。因此，t0时刻的状态构成了t0以前系统活动状态的完整历
37、史，它在一定范围内影响（系统）未来的行为。当前状态使得（系统）的过去和未来可以有很大的差别。,P2U5A Introduction to Modern Control Theory 第二部分第五单元课文A 现代控制理论简介,在任何固定的时刻，系统状态可以由一组变量xi的值来描述，xi称作状态变量。热力学系统的一个状态变量是温度，它的取值范围是连续实数域R。在二进制电路中，状态变量只能取两个离散的值或。注意，你在月末检查帐目的状态可以只用一个数来表示，平衡（指收支数）。联邦状况可以由国民生产总值、失业率、贸易赤字等表示。对于本文所考虑的系统，状态变量可以取任意实数或复数的标量值，即 xiC。尽管
38、一些系统需要无限多个状态变量，这里只考虑能够用有限的n个状态变量描述的系统。那么系统可以由一个n个元素的状态矢量x=x1 x2.xn T表示，它属于一个定义在域C上有n维矢量空间。对于连续时间系统，状态可以对某段时间内的所有时刻定义，例如一个连续变化的温度或电压。离散时间系统的状态只能定义在离散的时刻，如每月一次的财政报告或一个一度的联,P2U5A Introduction to Modern Control Theory 第二部分第五单元课文A 现代控制理论简介,邦状态消息。连续时间和离散时间系统可以通过定义要考察的时间为T来同时讨论。对于连续系统T由所有t t0,tf的实数组成，对于离散系
39、统，T由一组离散时间t0,t1,t2,tk构成。在许多情况下，每种系统初始时间都可以是-，最终时间可以是。状态矢量x(t)只在tT时定义。在任一给定t，很简单，它是一组n个有序的数。然而，系统特性会随着时间而改变，从而引起了所需状态变量数目的变化（不仅是值）。如果状态空间的维数随时间改变，就要使用符号t，这里假设在所有tT时有相同维数的n维状态空间。,补充：摘要的写作（一）,摘要(abstract)是位于正文之前的一段概括性文字，篇幅较短，层次清楚，字数一般在200300 字之间，便于译者翻译，读者查找信息。摘要具有独立性(可独立于论文全文)、概括性(简要概括论文的主要内容)和完整性，好的摘要
40、能让读者不阅读论文的全文就能获得必要的信息，因此常被科技工作者利用。,8.3 摘要的写作,摘要的特点,摘要包括能使读者理解全文的基本要素，能脱离原文独立存在；摘要是对原文高度的概括，信息量大；摘要要具有客观性和准确性。,8.3 摘要的写作,The direct torque control schemes of the permanent magnet synchronous motor(DTC-PMSM)are simply introduced in the paper.And the popular scheme is analyzed detailedly.Also,most impr
41、oved and researched techniques,including motor speed identification and advanced control algorithm used in DTC-PMSM,are introduced and analyzed recently.The future trend of the DTC-PMSM is also given at last.,本文简要介绍了永磁同步电机的直接控制方法，并详细分析了目前通用的控制策略。除此以外，还分析了改进研究技术，这些技术包括用于永磁同步电机中的电机速度检测方法与先进的控制策略。最后给出了
42、永磁同步电机的未来发展趋势。,8.3 摘要的写作,摘要的语言特征,1)时态和语态,当介绍具有普遍事实的背景资料时，多用一般现在时；当概述具有某种研究动向的背景资料时，多用现在完成时。在描述实验目的时，当以the paper 作主语或出现In this paper等类似的句式时，常用一般现在时态；当以The objective of或In this study,等类似的句式出现时，多用一般过去时。,现在科技文摘中为了生动、有力、直接，常使用主动语态。为了客观、强调、简洁也多使用被动语态。具体用什么时态应根据行文的需要，不能过于死板。,8.3 摘要的写作,This paper presents a
43、 new algorithm called both matched algorithm which is suitable to independent job scheduling on heterogeneous processor platforms.,本文提出了一种新的适于异构环境独立任务调度的双匹配算法。,Using digital signal processor(DSP),TMS320F240,we develop one frequency conversion adjustable-speed system based on FOC principle.,以电机控制专用的D
44、SP芯片TMS320F240为核心，设计开发了一套基于矢量控制的变频调速系统。,8.3 摘要的写作,A low-power low-cost highly efficient maximum power point tracker(MPPT)is proposed.,本文提出了一种小功率、价廉、高效的最大功率点跟踪器。,8.3 摘要的写作,2)名词化结构,摘要的语言特征,The basic method for the improvement of soil is the application of organic fertilizer.,科技文体摘要要求叙述重点突出，简练客观，信息丰富，逻
45、辑性强，而带有多个修饰语的名词化结构恰好能担此重任，因此科技论文摘要多用名词化结构。,The substitution of the new equipment for the old would result in a considerable increase in production.,新设备替代老设备将会使产量大大增加。,改良土壤的基本方法是使用有机肥。,3)长句,摘要的语言特征,科技论文摘要信息集中，逻辑结构分明，因此大量运用状语和其他修饰成分。如：,Basic functions as those of a grid-connected PV inverter,such as t
46、he maximum-power-point tracking and the anti-islanding protection,have been confirmed in the experiments using a distribution network simulator located in a laboratory.,运用实验室中的分布式网络模拟器对并网光伏逆变器的基本功能进行验证，这些基本功能如最大功率点跟踪和反孤岛保护。,8.3 摘要的写作,A zero-voltage-switched,full-bridge,phase-shifted DC-DC converter
47、for use in a DC power supply or battery charger includes a power transformer,four switching transistors connected to form a full bridge,and a decoupling capacitor and resonant inductor connected in series to the primary winding of the power transformer.,3)长句,8.3 摘要的写作,作业12：一、请将英文翻译成中文。1、part2:unit5:
48、B:第1段翻译；2、part2:unit5:B:第2段翻译；,P2U5B State Equations 第二部分第五单元课文B 状态方程,B 状态方程1.课文内容简介：主要介绍现代控制理论中状态空间模型、传递函数矩阵和稳定性等内容。2.温习现代控制理论中有关状态空间、特征方程等概念。3.生词与短语derivation n.起源，得来eliminate v.消除inherent adj.固有的equivalent adj.同等的，等效的；n.同等，等效dictate v.命令，要求uniform adj.一致的theme n.题目，主题，论文generalize v.概括，一般化，普及coor
49、dinate n.坐标，同等的人或物,P2U5B State Equations 第二部分第五单元课文B 状态方程,momenta n.动量，冲量Hamiltonian 哈密尔顿的Lagrangian 拉格朗日的superposition n.叠加inverse n.反，逆，倒数adjoint n.,adj.伴随（的），共轭（的）determinant n.行列式eigenvalue n.特征值（eigen-特征）exploit v.开发routines n.程序4.难句翻译1 In transfer function models these equations are transforme
50、d and variables are eliminated between them to find the relation between selected input and output variables.在传递函数模型中，这些方程经过（拉氏）变换，并消去中间变量，以求得选定的输入输出变量间的关系。,P2U5B State Equations 第二部分第五单元课文B 状态方程,2 The generalized coordinates and momenta of Hamiltonian and Lagrangian mechanics are,in fact,a set of s
