中国海洋大学自动化专英复习.docx

1、中国海洋大学自动化专英复习1. There are many situations where several variables are to be controlled simultaneously（同时地） by a number of inputs. Such systems are referred to as multivariable（多变量的） systems.很多情况下，几个变量同时被一系列的输入所控制。这样的系统称为多变量系统。2. In order to obtain more accurate（精确的） control, the controlled signal c(

2、t) must be fed back and compared with the reference input, and an actuating signal（作用信号） proportional to the difference of the output and the input must be sent through the system to correct the error.3. 为了得到更加精确的控制，控制信号c（t）必须被反馈回来并且与参考输入相比较，不同输入输出下作用信号的比例必须通过系统发送去修正误差。4. With the eyes blindfolded（蒙

3、上眼睛）, the feedback path is broken, and the human is operating as an open-loop system.（当一个人的）眼睛被蒙上后，反馈路径就被破坏了，那么这个人就作为开环系统运行了。5. Because all physical systems have electrical and mechanical inertia（惯性）, the position of the rudder（舵，方向舵） cannot respond instantaneously（即刻） to a step input, but will, rat

4、her, move gradually toward the final desired position.由于所有物理的系统都有电力和机械的惯性，所以方向舵的位置不能够及时的响应输入的阶跃信号，但是却更可能会逐步走向最终期望的位置。6. During actual operation, because of external disturbances（外部干扰）, uncertainties and irregularities of the web material, and the decrease of the effective diameter（直径） of the unwind（

5、展开） reel（卷）, the dancer arm will not remain horizontal（水平位置） unless some scheme is employed to properly sense the dancer-arm position and control the restraining（抑制的） braking torque（制动力矩）.实际操作过程中，由于外界干扰，不确定性、不规则的web材料，和展开卷轴有效直径的减少，松紧调节臂不会保持水平，除非运用一些方案去适当的检测到调节臂的位置并且控制受限的制动力矩。7. In reality, the reaso

6、ns for using feedback carry far more meaning than the simple one of comparing the input with the output in order to reduce the error.实际中，为了减少误差而运用反馈方式的原因远比简单的输入输出比较方式更加有意义。8. However, there are numerous situations wherein a physical system that we normally recognize as an inherently nonfeedback syst

7、em may turn out to have feedback when it is observed in a certain manner.然而，很多情况下我们通常认为的本质是非反馈的物理系统在特定的观测方式下可能就是具有反馈的系统。9. Stability is a notion that describes whether the system will be able to follow the input command. In a nonrigorous（非严酷的） manner, a system is said to be unstable if its output is

8、 out of control or increases without bound（限制）.稳定性是一个描述系统是否能跟随输入命令的概念。在非严格的方式下，系统被认为是不稳定的如果系统的输出不受控或者输出无限的增加。9、Since all physical elements have properties that change with environment and age, we can not always consider the parameters of a control system to be completely stationary over the entire o

9、perating life of the system.由于所有的物理元件都有随环境和年代改变的属性，因此我们不能总是认为控制系统的参数在系统的全部运行过程中是完全静止不变的。10、The effect of feedback on noise depends greatly on where the noise is introduced into the system; No general conclusions can be made. However, in many situations, feedback can reduce the effect of noise on sys

10、tem performance.噪声反馈的影响在很大程度上取决于噪声是从何处引入系统的，并不能得出一般的结论。然而，在许多情况下，反馈可以减小噪声对系统性能的影响。11、In general, feedback also has effects on such performance characteristics as bandwidth, impedance, transient response, and frequency response.一般来说，反馈也对像带宽、阻抗、暂态响应、以及频率响应等性能特征有影响。12、for linear systems there exists a

11、wealth of analytical and graphical techniques for design and analysis purposes. However nonlinear systems are very difficult to treat mathematically and there are no general methods that may be used to solve a wide class of nonlinear systems.对于线性系统，有许多分析的图形化的技术来实现设计和分析的目的。然而，非线性系统用数学方法则相当困难，并没有一个普遍的

12、方法可以应用于解决如此多种的非线性系统。13、When the parameters of a control system are stationary with respect to time during the operation of the system, we have a time-invariant system. Most physical systems contain elements that drift or vary time to some extent. If the variation of parameter is significant during t

13、he period of operation, the system is termed a time varying system. For instance, the radius of the unwind reel of the tension control system in Fig 1-7 decreases with time as the material is being transferred to the windup reel. Although a time-varying system without nonlinearity is still a linear

14、system, its analysis is usually much more complex than that of the linear time-invariant system当控制系统的参数在系统运行过程中随时间响应时不变的，我们就称它为是不变系统。大多数系统都包含有随时间的延伸儿漂移或变化的参数。如果在欲行期间参数变化明显，系统就被称作是一个时变系统。例如，图1-7的张力控制系统舒张轮的卷轴的半径随时间由于材料传到收缩轮上而减小。尽管一个时变系统没有非线性的特性，它的分析通常要比线性时不变系统复杂的多。.14、Sampled-data and digital control

15、systems differ from the continuous-data system in that the signals at one or more points of the system are in the form of either a pulse train or a digital code.离散和数字控制系统与连续系统的区别在于系统的信号在一个或做个点既不是脉冲序列的形式也不是数字代码的形式。15、Many airborne systems contain digital controllers that can pack several thousand dis

16、crete elements in a space no larger than the size of this book.许多空降系统包含数字控制器，它们在不大于这本书的空间里集成了几千个分离元件。16、When studying linear continuous-data systems, it is essential that one understands the concept of complex variable and functions of a complex variable when the transfer function method is used.研究线

17、性连续系统时，如果应用传递函数法，就又必要理解复杂变量和复杂变量函数的概念。17. Together with block diagram and signal flow graph, transfer function forms the basic of representing the input-output relationships of a linear time-invariant system in classical control theory.在经典控制理论中，传递函数连同结构图和信号流图是描述线性时不变系统输入输出关系的基本方式。18. However, it is

18、apparent that the differential equation method of describing a system, although essential, a rather cumbersome one, and the higher-order differential equation of Eq. (3-1) is of little practical use in design. More important is the fact that although efficient subroutines are available on digital co

19、mputers for the solution of high-order differential equations, the important development in linear control theory relies on analysis and design techniques without actual solutions of the system differential equations.然而，很明显，用微分方程来描述一个系统的方法是一种相当难处理的方法，尽管这种方法是最基本的，而且像方程3-1这样的高阶微分方程在设计中实际应用很少。更重要的是，虽然利

20、用数字计算机，有效的子程序可以使用来解决高阶微分方程，但在线性控制理论上的重要发展在于分析和设计工艺，没有系统微分方程的实际解决方案。cumbersome笨重的，不方便的，累赘的，难处理的。Subroutine子程序。19. Since the principle of superposition is valid for linear systems, the total effect on any output variable due to all the inputs acting simultaneously can be obtained by adding the individ

21、ual effects.既然叠加特性对线性系统是有效的，由于所有输入同时作用，通过添加个别的影响，所有输出变量的全部影响可以被获取。Superposition叠加。Simultaneously同时地。20. The impulse response of a linear system is defined as the output response of the system when the input is a unit impulse function.当输入是单位脉冲函数时，线性系统的脉冲响应被定义为这个系统的输出响应。21. Since the transfer function

22、 is a powerful way of characterizing linear systems, this means that if a linear system has zero initial conditions, theoretically, the system can be described or identified by exciting it with a unit impulse response and measuring the output.既然传递函数是描述线性系统特性的一种有效方式，这就意味着如果一个线性系统有零初始条件，理论上说，这个系统可以通过用

23、单位脉冲响应激发它和测量输出来描述或确认。impulse response脉冲响应。Theoretically理论上。22. In order that the system may have the ability of self-correction or self-adjustment in accordance with varying parameters and environment, it is necessary that the systems transfer characteristics be identified continuously or at appropr

24、iate intervals during the operation of the system.为了使系统能够根据变化的参数和环境而进行自校正和自调整，在系统运行时，连续不断的或在合适的时间间隔内对系统传递特性进行确认是很必要的。Interval时间间隔。Parameters参数。23. If the mathematical and functional relationships of all the system elements are known, the block diagram can be used as a reference for the analytical or

25、 the computer solution of the system. 如果系统的所有元件的数学和功能关系都是已知的，那么这个结构框图可以作为系统分析和计算机解决方案的一种参考。24. In general, a practical control system may contain many feedback loops, and the evaluation of the transfer function from the block diagram by means of the algebraic method described above may be tedious.一般

26、来说，一个实际控制系统可能包含许多反馈回路，并且对结构图中的传递函数的评估通过上述的代数方法来描述可能是冗长的。Algebraic代数的。Tedious冗长的。25. It should be mentioned that although the development of the input-output relationship here is similar to that of the single input-out case, in the present situation it is improper to speak of the ratio C(s)/R(s) sinc

27、e C(s) and R(s) are matrices.应当指出，尽管在这的输入输出关系的发展与单输入输出情况很相似，从现状看，因为C(s)和R(s)是矩阵，所以提及他们的比C(s)/R(s)是不正确的。26. In general, besides the difference in the physical appearances of the signal flow graph and the block diagram, we may regard the signal flow graph to be constrained by more rigid mathematical r

28、elationships, whereas the rules of using the block-diagram notation are far more flexible and less stringent.通常，除了在信号流程图和方框图的物理性质方面的差别外，我们也可以把信号流程图当做是被更多严格的数学关系所驱使，然而使用图标符号的规则更灵活，也不会那么迫切。27. Since the only proper way that a signal flow graph can be drawn is from a set of cause-and-effect equations,

29、that is, with the causes on the right side of the equation and the effects on the left side of the equation, we must transfer y2 to the right side of Eq.(3-60) if it were to be an input.既然唯一适当的可以绘制信号流程图的方法是来自源于一组有因果关系的方程式，也就是说，由于方程右侧的是原因，方程左侧的是结果，如果y2是一个输入的话，我们必须把他转换到方程3-60的右侧。28. In the analysis pr

30、oblem, a reference input signal is applied to a system, and the performance of the system is evaluated by studying the response in the time domain.在分析问题中，一个标准输入信号作用于一个系统，在时域中分析系统的响应，系统的性能就会被评估出来。29. Therefore, a sine wave is considered as a steady-state response because its behavior is fixed for any

31、 time interval, as when time approaches infinity.因此，当时间趋近于无穷大时，正弦波被看做一个稳态响应，因为他的动作存在于任何时间间隔中。30. Since inertia, mass, and inductance cannot be avoided in physical systems, the responses cannot follow sudden changes in the input instantaneously, and transients are usually observed.因为在物理系统中惯性，质量和电感是无法

32、避免的，系统不能响应突如其来的输入变化，这个变化的瞬态通常是可观测的。31.The transient response of the control system is ofimportance, since it is part of the dynamic behavior of the system; and the deviation between the response and the input or the desired response ,before the steady state is reached , must be closely watched. 控制系统的瞬态响应是非常重要的，因为它属于系统动态特性的组成部分；在系统达到稳态之前，系统响应与输入或者说预期响应之间的偏差，必须被紧密的观测。32. By selecting these basic test signals properly, not only the mathematical treatment of the problem is systematized , but the responses due to these inputs allow the prediction of the system