自动化专业外文文献

1、Development of Sensor New TechnologySensor is one kind component which can transform the physical quantity, chemistry quantity and the biomass into electrical signal. The output signal has the different forms like the voltage, the electric current, the frequency, the pulse and so on, which can satis

2、fy the signal transmission, processing, recording, and demonstration and control demands. So it is the automatic detection system and in the automatic control industry .If automatic Technology is used wider, then sensor is more important.Several key words of the sensor：1 Sensor ElementsAlthough ther

3、e are exception ,most sensor consist of a sensing element and a conversion or control element. For example, diaphragms,bellows,strain tubes and rings, bourdon tubes, and cantilevers are sensing elements which respond to changes in pressure or force and convert these physical quantities into a displa

4、cement. This displacement may then be used to change an electrical parameter such as voltage, resistance, capacitance, or inductance. Such combination of mechanical and electrical elements form electromechanical transducing devices or sensor. Similar combination can be made for other energy input su

5、ch as thermal. Photo, magnetic and chemical,giving thermoelectric, photoelectric,electromaanetic, and electrochemical sensor respectively.2 Sensor SensitivityThe relationship between the measured and the sensor output signal is usually obtained by calibration tests and is referred to as the sensor s

6、ensitivity K1= output-signal increment / measured increment . In practice, the sensor sensitivity is usually known, and, by measuring the output signal, the input quantity is determined from input= output-signal increment / K1.3 Characteristics of an Ideal SensorThe high sensor should exhibit the fo

7、llowing characteristics.(a)high fidelity-the sensor output waveform shape be a faithful reproduction of the measured; there should be minimum distortion.(b)There should be minimum interference with the quantity being measured; the presence of the sensor should not alter the measured in any way.(c)Si

8、ze. The sensor must be capable of being placed exactly where it is needed.(d)There should be a linear relationship between the measured and the sensor signal.(e)The sensor should have minimum sensitivity to external effects, pressure sensor,for example,are often subjected to external effects such vi

9、bration and temperature.(f)The natural frequency of the sensor should be well separated from the frequency and harmonics of the measurand.Sensors can be divided into the following categories：1 Electrical SensorElectrical sensor exhibit many of the ideal characteristics. In addition they offer high s

10、ensitivity as well as promoting the possible of remote indication or mesdurement.Electrical sensor can be divided into two distinct groups:(a)variable-control-parameter types,which include:(i)resistance(ii)capacitance(iii)inductance(iv)mutual-inductance typesThese sensor all rely on external excitat

11、ion voltage for their operation.(b)self-generating types,which include(i)electromagnetic(ii)thermoelectric(iii)photoemissive(iv)piezo-electric typesThese all themselves produce an output voltage in response to the measurand input and their effects are reversible. For example, a piezo-electric sensor

12、 normally produces an output voltage in response to the deformation of a crystalline material; however, if an alternating voltage is applied across the material, the sensor exhibits the reversible effect by deforming or vibrating at the frequency of the alternating voltage.2 Resistance SensorResista

13、nce sensor may be divided into two groups, as follows:(i)Those which experience a large resistance change, measured by using potential-divider methods. Potentiometers are in this group.(ii)Those which experience a small resistance change, measured by bridge-circuit methods. Examples of this group in

14、clude strain gauges and resistance thermometers.3 Capacitive SensorThe capacitance can thus made to vary by changing either the relative permittivity, the effective area, or the distance separating the plates. The characteristic curves indicate that variations of area and relative permittivity give

15、a linear relationship only over a small range of spacings. Thus the sensitivity is high for small values of d.  Unlike the potentionmeter, the variable-distance capacitive sensor has an infinite resolution making it most suitable for measuring small increments of displacement or quantities

16、 which may be changed to produce a displacement.4 Inductive SensorThe inductance can thus be made to vary by changing the reluctance of the inductive circuit.Measuring techniques used with capacitive and inductive sensor:(a)A.C. excited bridges using differential capacitors inductors.(b)A.C. potenti

17、ometer circuits for dynamic measurements.(c)D.C. circuits to give a voltage proportional to velocity for a capacitor.(d)Frequency-modulation methods, where the change of C or L varies the frequency of an oscillation circuit.Important features of capacitive and inductive sensor are as follows:(i)reso

18、lution infinite(ii)accuracy±0.1% of full scale is quoted(iii)displacement ranges 25*10-6 m to 10-3m(iv)rise time less than 50us possibleTypical measurands are displacement, pressure, vibration, sound, and liquid level.5 Linear Variable-differential Ttransformer6 Piezo-electric Sensor7 Electroma

19、gnetic Sensor8 Thermoelectric Sensor9 Photoelectric Cells10 Mechanical Sensor and Sensing ElementsIn information age, the information industry includes information gathering, transmission, process three parts, namely sensor technology, communication, computer technology. Because of ultra large scale

20、 integrated circuits rapid development after having been developed Modern computer technology and communication, not only requests sensor precision reliability, speed of response and gain information content request more and more high but also requests its cost to be inexpensive. The obvious traditi

21、onal sensor is eliminated gradually because of the function, the characteristic, the volume, the cost and so on. As world develop many countries are speeding up to the sensor new technologys research and the development, and all has obtained the enormous breakthrough. Now the sensor new technology d

22、evelopment mainly has following several aspects:Using the physical phenomenon, the chemical reaction, the biological effect as the sensor principle therefore the researches which discovered the new phenomenon and the new effect are the sensor technological improving ways .it is important studies to

23、developed new sensors the foundation. Japanese Sharp Corporation uses the superconductivity technology to develop successfully the high temperature superconductivity magnetic sensor and get the sensor technology significant breakthrough. Its sensitivity is so high and only inferior in the supercondu

24、ctivity quantum interference component. Its manufacture craft is far simpler than the superconductivity quantum interference component. May use in magnetism image formation technology. So it has the widespread promoted value.Using the immune body and the antigen meets one another compound when the e

25、lectrode surface. It can cause the electrode potential change and use this phenomenon to be possible to generate the immunity sensor. The immunity sensor makes with this kind of immune body may to some organism in whether has this kind of ant original work inspection. Like may inspect somebody with

26、the hepatitis virus immune body whether contracts the hepatitis, plays to is fast, the accurate role. The US UC sixth branch has developed this kind of sensor.The sensor material is the important foundation for sensor technology, because the materials science is progressive and the people may make e

27、ach kind of new sensor For example making the temperature sensor with the high polymer thin film; The optical fiber can make the pressure, the current capacity, the temperature, the displacement and so on the many kinds of sensors; Making the pressure transmitter with the ceramics. The high polymer

28、can become the proportion adsorption and the release hydrogen along with the environment relative humidity size. The high polymer electricity lies between the constant to be small, the hydrogen can enhance the polymer the coefficient of dialectical loss. Making the capacitor the high polymer dielect

29、ric medium, determines the electric capacity cape city the change, then obtains the relative humidity. Making the plasma using this principle to gather the legitimate polystyrene film temperature sensor below, it has the characteristic.Measured the wet scope is wide; The temperature range is wide, m

30、ay reach -400 +1,500 ; The speed of response is quick, is smaller than 1S; The size is small, may use in the small space measuring wet; The temperature coefficient is small.The ceramic electric capacity type pressure transmitter is one kind does not have the intermediary fluid the dry type pressure

31、transmitter. Uses the advanced ceramic technology, the heavy film electronic technology, its technical performance is stable, the year drifting quantity is smaller than 0.1%F.S, warm floats is smaller than ±0.15%/10K, anti- overloads strongly, may reach the measuring range several hundred times

32、. The survey scope may from 0 to 60mpa.German E+H Corporation and the American Kahlo Corporation product is at the leading position.The optical fiber application is send the material significant breakthrough, its uses in most early the optical communication techniques. In the optical communication u

33、se discovered works as environmental condition change and so on the temperature, pres-sure, electric field, magnetic field, causes the fiber optic transmission light wave intensity, the phase, the frequency, change and so on the polarization condition, the survey light wave quantity change, may know

34、 causes these light wave physical quantity the and so on quantitative change temperature, pressure ,electric field, magnetic field size, uses these principles to be possible to develop the optical fiber sensor. The optical fiber sensor and the traditional sensor compare has many characteristics: Sen

35、sitivity high, the structure simple, the volume small, anti-corrosive, the electric insulation good, the path of rays may be curving, be advantageous for the realization telemeter and so on. Optical fiber sensor Japan is in the advanced level. Like Idec Izumi Corporation and Sun x Corporation. The o

36、ptical fiber send receiver and the integrated path of rays technology unify, accelerates the optical fiber sensor technology development. Will integrate the path of rays component to replace the original optics part and the passive light component; enable the optical fiber sensor to have the high ba

37、nd width, the low signal processing voltage, the reliability high, the cost will be low.In semiconductor technology processing method oxygenation, the photo etc hang, the proliferation, the deposition, the plane electron craft, various guides corrosion and steams plates, the sputtering thin film and

38、 so on, these have all introduced to the sensor manufacture. Thus has produced each kind of new sensor, like makes the silicon micro sensor using the semiconductor technology, makes the fast response using the thin film craft the gas to be sensitive, the wet sensitive sensor, the use sputtering thin

39、 film craft system pressure transmitter and so on.The Japanese horizontal river company uses various guides corrosion technology to carry on the high accuracy three dimensional processing; the system helps the silicon resonance type pressure transmitter. The core partially presses two resonant Liang

40、 by the feeling which above the silicon diaphragm and the silicon diaphragm manufactures to form, two resonant Liang's frequency difference correspondence different pressure, measures the pressure with the frequency difference method, may eliminate the error which factor and so on ambient temper

41、ature brings. When ambient temperature change, two resonant Liang frequencies and the amplitude variation are same, after two frequency differences, its same change quantity can counterbalance mutually. Its survey most high accuracy may reach 0.01%FS.American Silicon Microstructure Inc.(SMI) the com

42、pany develops a series of low ends, linear in 0.1% to 0.In 65% scope silicon micro pressure transmitter, the lowest full measuring range is 0.15psi (1KPa), it makes take the silicon as the material, has the unique three dimensional structure, the light slight machine-finishing, makes the wheat stone

43、 bridge many times with the etching on the silicon diaphragm, when above silicon chip stress, it has the distortion, the resistance produces presses the anti- effect but to lose the bridge balance, the output and the pressure becomes the proportion the electrical signal.Such silicon micro sensor is

44、the front technology which now the sensor develops, Its essential feature is the sensitive unit volume is a micron magnitude, Is the traditional sensor several dozens, several 1%. In aspect and so on industry control, aerospace domain, biomedicine has the vital role, like on the airplane the use may

45、 reduce the airplane weight, reduces the energy. Another characteristic is can be sensitive is small surveyed, may make the blood pressure pressure transmitter.The Chinese aviation main corporation Beijing observation and control technical research institute, the development CYJ series splashes than

46、ks the membrane pressure transmitter is uses the ion sputtering craft to process the metal strain gauge, it has over come the nonmetallic strain gauge easily the temperature influence insufficiency, has the high stability, is suitable in each kind of situation, is measured the medium scope widely, b

47、ut also overcame the tradition lowly to glue the precision which the type brought, sluggish big, shortcoming and so on slow change, had the precision high, the re-liability is high, the volume small characteristic, widely used in domain and so on aviation, petroleum, chemical industry, medical servi

48、ce.Integrates the sensor the superiority is the traditional sensor is unable to achieve, it is a simple sensor not merely, it in at the same time the auxiliary circuit part and send the part will integrate on together the chip, will cause it to have the calibration, to compensate, from the diagnosis

49、 and the network correspondence function, it might reduce the cost, the gain in yield, this kind of blood pressure sensor which American LUCAS, NOVASENSOR Corporation will develop, each week will be able to produce 10,000.The intellectualized sensor is one kind of belt microprocessor sensor, is achi

50、evement which the microcomputer and the sensor unifies, it has at the same time the examination, the judgment and the information processing function, compares with the traditional sensor has very many characteristics:Has the judgment and the information processing function, can carry on the revisio

51、n, the error to the observed value compensates, thus enhancement measuring accuracy; May realize the multi-sensor multi parameters survey; Has from the diagnosis and from the calibration function, enhances the reliability; The survey data may deposit and withdraw, easy to operate; Has the data commu

52、nication interface, can and the microcomputer direct communication.The sensor, the signal adjustment electric circuit, the monolithic integrated circuit integration forms ultra large-scale integrated on a chip the senior intelligence sensor. American HONY WELL Corporation ST-3000 intelligence sensor

53、, the chip size only then has 3×4×2mm3, uses the semiconductor craft, makes CPU, EPROM, the static pressure, the differential pressure, the temperature on the identical chip and so on three kind of sensitive units.The intellectualized sensor research and the development, US is at the leadi

54、ng position. American Space Agency when development spaceship called this kind of sensor for the clever sensor (Smart Sensor), on the spaceship this kind of sensor is extremely important. Our country in this aspect research and development also very backward mainly is because our country semiconduct

55、or integrated circuit technological level is limited.The sensors development is changing day after day since especially the 80's humanities have entered into the high industrialization the information age, sensor techno-logy to renewal, higher technological development. US, Japan and so on devel

56、oped country sensor technological development quickest, our country because the foundation is weak, the sensor technology compares with these developed countries has the big disparity. Therefore, we should enlarge to the sensor engineering research, the development investment, causes our country sen

57、sor technology and the foreign disparity reduces, promotes our country instrument measuring appliance industry and from the technical development.FromSensor Technology Handbook,Jon Wilson,Newnes传感器新技术的发展传感器是一种能将物理量、化学量、生物量等转换成电信号的器件。输出信号有不同形式，如电压、电流、频率、脉冲等，能满足信息传输、处理、记录、显示、控制要求，是自动检测系统和自动控制系统中不可缺少的元

58、件。如果把计算机比作大脑，那么传感器则相当于五官，传感器能正确感受被测量并转换成相应输出量，对系统的质量起决定性作用。自动化程度越高，系统对传感器要求越高。传感器的几个关键词：1传感器元件除特例外，大多数的传感器都由敏感元件、转换元件或控制元件组成。如振动膜、波纹管、应力管和应力环、低音管和悬臂都是敏感元件，它们对压力和力作出响应把物理量转变成位移。然后位移可以改变电参数，如电压、电阻、电容或者感应系数。机械式和电子式元件合并形成机电式传感设备或传感器。这样的组合可用来输入能量信号。热的，光的，磁的和化学的相互结合产生的热电式、光电式、电磁式和电化学式传感器。2 传感器灵敏度通过校正测量系统获

59、得的被测物理量和传感器输出信号的关系叫做传感器灵敏度K1，也就是K1=输出信号增量/测量增量。实际中，传感器的灵敏度是已知的，并且通过测量输出信号，输入量由下式决定，输入量=输出信号增量/K1。3 理想传感器的特性（a）高保真性：传感器输出波形应该真实可靠地再现被测量，并且失真很小。（b）可测量最小的干扰，任何时候传感器的出现不能改变被测量。（c）尺寸：传感器必须能正确地放在所需的地方。（d）被测量和传感器信号之间应该有一个线性关系。（e）传感器对外部影响的灵敏度应该小，例如压力传感器经常受到外部振动和温度的影响。（f）传感器的固有频率应该避开被测量的频率和谐波。传感器可分为以下几类：1 电传感器电传感器具有许多理想特性。它们不仅实现远程测量和显示，还能提供高灵敏度。电传感器可分为两大类。（a）变参