自动化专业外文文献(共13页).doc

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1、精选优质文档-倾情为你奉上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, wh

2、ich can satisfy 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 Elements

3、Although there 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

4、into a displacement. 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 en

5、ergy input such 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

6、 the sensor sensitivity 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 e

7、xhibit the following 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

8、any way.(c)Size. 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 ef

9、fects such vibration 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

10、 offer high sensitivity 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 ext

11、ernal excitation 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-el

12、ectric sensor 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

13、SensorResistance 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

14、this group include 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 permi

15、ttivity give 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 quantitie

16、s 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. potent

17、iometer 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)res

18、olution infinite(ii)accuracy0.1% 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 Electromagneti

19、c 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 inte

20、grated 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 traditional

21、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 develo

22、pment 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 devel

23、oped 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 superconductivi

24、ty 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 electr

25、ode 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 the h

26、epatitis 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 each k

27、ind 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 can b

28、ecome 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 dielectric m

29、edium, 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, may re

30、ach -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 trans

31、mitter. 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. The surve

32、y 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 use discover

33、ed 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 causes the

34、se 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: Sensitivity hi

35、gh, 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 optical fibe

36、r 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 band width, t

37、he 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 so on, the

38、se 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 film craft

39、 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 by the fee

40、ling which above the silicon diaphragm and the silicon diaphragm manufactures to form, two resonant Liangs frequency difference correspondence different pressure, measures the pressure with the frequency difference method, may eliminate the error which factor and so on ambient temperature brings. Wh

41、en 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 company develops a

42、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 bridge many tim

43、es 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 the front techno

44、logy 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 reduce the airp

45、lane 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 thanks the membrane

46、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, but also overcame

47、 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 service.Integrates th

48、e 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 and the network

49、 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 achievement which the microcomputer and the sensor unifies, it has at the same time the examination, the judgment and the information processing function, comp