专业英语第八章.docx

1、专业英语第八章Analog Sensors for Moti0n Measurement8.3.1 Introduction Measurement of plant outputs is essential for feedback control. Output measurements are also useful in performance evaluation of a process. Furthermore, in learning systems (e.g., teach-repeat operation of robotic manipulators), measurem

2、ents are made and stored in the computer for subsequent use in operating the system. Input measurements are needed in feed forward control. It is evident, therefore, that the measurement subsystem is an important part of a control system.8.3 用于运动测量的模拟传感器8.3.1 引言/导论/简介对反馈控制来说，被控对象输出的测量是基本的。输出测量在过程的性能

3、评价中也很有用。而且，在学习系统（例如，机械手的示教-重现操作）中，进行测量并将测量结果存储在计算机中，用于随后的系统运行。在前馈控制中，需要对输入量进行测量。因此，很明显，测量子系统是一个控制系统的重要组成部分。The measurement subsystem in a control system contains sensors and transducers that detect misbrands and convert them into acceptable signals-typically, voltages. These voltage signals are then

4、 appropriately modified using signal-conditioning hardware such as filters, amplifiers, demodulators, and analog-to-digital converters. Impedance matching might be necessary to connect sensors and transducers to signal-conditioning hardware.控制系统的测量子系统包含传感器和变送器，它们检测被测量并将被测量转换成可接受的信号通常是电压信号。接着，这些电压信号被

5、适当的调理，所用的信号调理硬件有滤波器、放大器、解调器和模-数转换器。传感器和变送器与信号调理硬件之间的连接，阻抗匹配是必须的。Accuracy of sensors, transducers, and associated signal-conditioning devices is important in control system applications for two main reasons. The measurement system in a feedback control system is situated in the feedback path of the c

6、ontrol system. Even though measurements are used to compensate for the poor performance in the open-loop system, any errors in measurements themselves will enter directly into the system and cannot be corrected if they are unknown. Furthermore, it can be shown that sensitivity of a control system to

7、 parameter changes in the measurement system is direct. This sensitivity cannot be reduced by increasing the loop gain, unlike in the case of sensitivity to the open-loop components. Accordingly, the design strategy for closed-loop (feedback) control is to make the measurements very accurate and to

8、employ a suitable controller to reduce other types of errors.传感器、变送器和辅助信号调理装置的精度在控制系统应用是重要的，主要有两个原因。反馈控制系统的测量系统位于控制系统的反馈回路，尽管在开环系统中，测量可用于补偿不良特性，但测量本身的误差会直接进入系统，如果误差未知，则无法校正。而且，可以看出，控制系统对参数变化的敏感性在测量系统中是直接的，与开路部件敏感性情形不同，这种敏感性不能通过增大回路增益方法进行减小。因而，对反馈控制系统来说，其设计策略是使测量非常精确，并采用合适的控制器降低其它类型的误差。 Most sensor-t

9、ransducer devices used in feedback control applications are analog components that generate analog output signals. This is the case even in real-time direct digital control systems. When analog transducers are used in digital control applications, however, some type of analog-to-digital conversion (

10、ADC) is needed to obtain a digital representation of the measured signal. The resulting digital signal is subsequently conditioned and processed using digital means.在反馈控制应用中，大多数传感器-变送器装置是产生模拟信号的模拟部件。即使是在实时直接数字控制系统中，也是如此。然而，当模拟变送器应用在数字控制场合时，为了获得被测信号的数字表示，必须采用某种类型的模数转换。所获得的数字信号应用数字方法进行后续调理和处理。In the s

11、ensor stage, the signal being measured is felt as the “response of the sensor element.” This is converted by the transducer into the transmitted (or measured) quantity. In this respect, the output of a measuring device can be interpreted as the “response of the transducer.” In control system applica

12、tions, this output is typically (and preferably) an electrical signal. Note that it is somewhat redundant to consider electrical-to-electrical sensors-transducers as measuring devices, particularly in control system studies, because as measuring devices, particularly in control system studies, becau

13、se electrical signals need conditioning only before they are fed into a controller or to a drive system. In this sense, electrical-to-electrical transduction should be considered a “conditioning” task rather than a “measuring” function. 在传感阶段，被测信号可以看作是“传感单元的响应”。该信号被变送器转换成被传输的信号量。在这一方面，测量装置的输出可以看作是“变

14、送器的响应”。在控制系统应用中，该输出信号通常（更可取地）是一个电气信号。注意，把电气信号到电气信号的传感器-变送器看作是测量装置有些多余，尤其是在控制系统研究中，因为只有在电气信号被送入控制器或驱动系统之前，才需要进行调理。在这种意义上，电气信号到电气信号的变送可以被看作是一个“信号调理”任务而不是“测量”功能。 8.3.2 Motion Transducers By motion, we mean the four kinematic variables: Displacement (including position, distance, proximity, and size or

15、gage) Velocity Acceleration Jerk 8.3.2 运动传感器就运动而言，我们指的是四个运动学变量： 位移（包括位置、距离、接近度和尺寸或厚度）； 速度； 加速度； 冲击；Note that each variable is the time derivative of the preceding one. Motion measurements are extremely useful in controlling mechanical responses and interactions in dynamic systems. Numerous examples

16、can be cited of situations in which motion measurements are used for control purposes. The rotating speed of a work piece and the feed rate of a tool are measured in controlling machining operations. Displacements and speeds (both angular and translator) at joints (revolute and prismatic) of robotic manipulators for kinematic linkages are used in controlling manipulator trajectory. In high-speed ground transit vehicles, acceleratio