1、 试题纸 课程名称： Specified English 适用专业年级： 考生学号： 考生姓名： 1. Words and Terms(1) Please give the complete expression of the abbreviated words, and give the Chinese meaning. (210)1) TF2) D/A 3) IC 4) I/O5) ALU6) CPU 7) PID8) MIMO9) GNP10) VLSI(2) Please translate the English words or terms into Chinese. (120)1
2、) discrete system2) setting time3) state variable4) inverse transform5) Laplace domain6) dynamic response7) automatic process control8) complex domain9) initial value10) classical control11) gate circuit12) transient response13) percent overshoot14) performance criteria15) differential equation16) d
3、evelopment system17) final control system18) optimal control19) open loop20) linear vector space2. Please translate the following sentences into Chinese. (56)(1) Designing a control system is not a precise or well-defined process; rather, it is a sequence of interrelated events. A typical sequence m
4、ight be1) modeling of the plant; 2) linearization of the plant model;2) dynamic analysis of the plant; 4) nonlinear simulation of the plant;5) establishment of the control philosophy & strategy; 6) selection of the performance criteria and indices;7) design of the controller; 8) dynamic analysis of
5、the complete system;9) nonlinear simulation of the complete system; 10) selection of the hardware to be used;11) construction and test of the development system; 12) design of the production model;13) test of the production model (2) open-loop and closed loop control systems. An open-loop system is
6、one in which the control action is independent of the output. A closed-loop system, however, the input of the plant is somehow dependent on the actual output. Since the output is fed back in a functional form determined by the nature of the feedback elements and then subtracted from the input，a clos
7、e-loop system is often referred to as a negative feedback system or simply as a feedback system.(3) With an advancing technological society, there is a trend towards more ambitious goals. This also means dealing with complex systems with a larger number of interacting components. The need for greate
8、r accuracy and efficiency has changed the emphasis on control system performance. The classical specifications in terms of percent overshoot, setting time, bandwidth, etc., have in many cases given way to optimal criteria such as minimum energy, minimum cost, and minimum time operation.(4) The Lapla
9、ce transformation comes from the area of operational mathematics and is extremely useful in the analysis and design of linear systems. Ordinary differential equations with constant coefficients transform into algebraic equations that can be used to implement the transfer function concept. Furthermor
10、e, the Laplace domain is a nice place in which to work, and transfer functions may be easily manipulated, modified, and analyzed. (5) In NAND and NOR gates ( as well as an AND and OR gates), when it serves our purpose to do so, we can arbitrarily select one input terminal and view it as an enable-di
11、sable input. Thus, consider a NOR or an OR gate. If the one selected input is at logic 1, the output of the gate is independent of all other inputs. this one selected input takes control of the gate and the gate is disabled with respect to any other input.(6) The importance of these components is th
12、at they perform the three basic operations that must be present in every control system. these operations are:1) measurement(M): measuring the variable to be controlled is usually done by the combination of sensor and transmitter.2) Decision(D):based on the measurement, the controller must then deci
13、de what to do to maintain the variable at its desired value.3) Action(A): as a result of the controllers decision, the system must then take an action. This is usually accomplished by the final control element.3. Please translate the following sentences into English. (10)PID控制是将比例、积分、微分三种控制规律结合一起。比例
14、环节的作用是，当偏差一旦产生时，比例调节立即发挥作用，以减少偏差；积分的作用是消除余差；微分的作用是反映偏差的变化，并能在偏差信号变大前，在系统中引入一个有效的修正，从而加快系统的动作速度，减少调节时间。4. Please give Abstract and Key words about the following paper. (15+5)At this time it is necessary to define some terms used in the field of automatic process control. The first term is controlled
15、variable. This is the variable that must be maintained or controlled at some desired value. In the preceding example, the process outlet temperature, , is the controlled variable. The second term is set point, the desired value of controlled variable. The manipulated variable is the variable used to
16、 maintain the controlled variable at its set pint. In the example, the flow of steam is the manipulated variable. Finally, any variable that can cause the controller variable to deviate away from set point is defined as a disturbance or upset. In most process there are s number of different disturba
17、nces.What is important here is to understand that in the process industries, most often it is because of this disturbance that automatic process control is needed. If there were no disturbances, design-operating conditions would prevail and there would be no necessity of continuously “policing” the
18、process.The following additional terms are also important. Open loop refers to the condition in which the controller is disconnected from the process. That is , the controller is not making the decision of how to maintain the controlled variable at set point. Another instance in which open-loop cont
19、rol exists is when the action(A) taken by controller does not affect the measurement(M). This is indeed a major flaw in the control system design. Close-loop control refers to the condition in which the controller is connected to the process, comparing the set point to the controlled variable and de
20、termining corrective action.With these terms defined, the objective of an automatic process control system can be stated as follows; the objective of an automatic process control system is to use the manipulated variable to maintain the controlled variable at its point in spite of disturbance.注：1、教师命题时题目之间不留空白； 2、考生不得在试题纸上答题，教师只批阅答题册正面部分。（第 4 页）
