位移傳感器-(中英對照)

1、位移傳感器位移傳感器又稱為線性傳感器,它分為電感式位移傳感器,電容式位移傳 感器, 光電式位移傳感器, 位移傳感器超聲波式位移傳感器, 霍爾式位移傳感器。 電感式位移傳感器是一種屬于金屬感應(yīng)的線性器件, 接通電源后, 在開關(guān)的感應(yīng) 面將產(chǎn)生一個交變磁場, 當(dāng)金屬物體接近此感應(yīng)面時, 金屬中則產(chǎn)生渦流而吸取 了振蕩器的能量, 使振蕩器輸出幅度線性衰減, 然后根據(jù)衰減量的變化來完成無 接觸檢測物體的目的。簡介電感式位移傳感器具有無滑動觸點(diǎn), 工作時不受灰塵等非金屬因素的影 響,并且低功耗,長壽命,可使用在各種惡劣條件下。位移傳 感器主要應(yīng) 用在自動化裝備生產(chǎn)線對模擬量的智能控制。位移是和物體的位置

2、在運(yùn)動過程中的移動有關(guān)的量,位移的測量方式 所涉及的范圍是相當(dāng)廣泛的。小位移通常用應(yīng)變式、電感式、 差動變壓器 式、渦流式、霍爾傳感器來檢測,大的位移常用感應(yīng)同步器、光柵、容柵、 磁柵等傳感技術(shù)來測量。 其中光柵傳感器因具有易實(shí)現(xiàn)數(shù)字化、 精度高 (目 前分辨率最高的可達(dá)到納米級、抗干擾能力強(qiáng)、沒有人為讀數(shù)誤差、安 裝方便、使用可靠等優(yōu)點(diǎn),在機(jī)床加工、檢測儀表等行業(yè)中得到日益廣泛 的應(yīng)用。原理計量光柵是利用光柵的莫爾條紋現(xiàn)象來測量位移的。 “莫爾”原出于法 文 Moire ,意思是水波紋。幾百年前法國絲綢工人發(fā)現(xiàn),當(dāng)兩層薄絲綢疊在 一起時,將產(chǎn)生水波紋狀花樣;如果薄綢子相對運(yùn)動,則花樣也跟著移

3、動, 這種奇怪的花紋就是莫爾條紋。一般來說,只要是有一定周期的曲線簇重 疊起來,便會產(chǎn)生莫爾條紋。計量光柵在實(shí)際應(yīng)用上有透射光柵和反射光 柵兩種;按其作用原理又可分為輻射光柵和相位光柵;按其用途可分為直 線光柵和圓光柵。下面以透射光柵為例加以討論。透射光柵尺上均勻地刻 有平行的刻線即柵線, a 為刻線寬, b 為兩刻線之間縫寬, W=a+b稱為光柵 柵距。目前國內(nèi)常用的光柵每毫米刻成 10、 25、 50、 100、 250條等線條。 光柵的橫向莫爾條紋測位移,需要兩塊光柵。一塊光柵稱為主光柵,它的 大小與測量范圍相一致;另一塊是很小的一塊,稱為指示光柵。為了測量 位移,必須在主光柵側(cè)加光源,

4、在指示光柵側(cè)加光電接收元件。當(dāng)主光柵 和指示光柵相對移動時,由于光柵的遮光作用而使莫爾條紋移動,固定在 指示光柵側(cè)的光電元件,將光強(qiáng)變化轉(zhuǎn)換成電信號。由于光源的大小有限 及光柵的衍射作用,使得信號為脈動信號。信號處理辨向原理在實(shí)際應(yīng)用中,位移具有兩個方向,即選定一個方向后,位移有正負(fù)之 分,因此用一個光電元件測定莫爾條紋信號確定不了位移方向。為了辨向, 需要有 /2相位差的兩個莫爾條紋信號。細(xì)分技術(shù)隨著對測量精度要求的提高,以柵距為單位已不能滿足要求,需要采取 適當(dāng)?shù)拇胧δ獱枟l紋進(jìn)行細(xì)分。所謂細(xì)分就是在莫爾條紋信號變化一個 周期內(nèi),發(fā)出若干個脈沖,以減少脈沖當(dāng)量。如一個周期內(nèi)發(fā)出 n 個脈沖

5、, 則可使測量精度提高 n 備,而每個脈沖相當(dāng)于原來柵距的 1/n。由于細(xì)分后 計數(shù)脈沖頻率提高了 n 倍,因此也稱 n 倍頻。通常用的有兩種細(xì)分方法:其一、直接細(xì)分。在相差 1/4莫爾條紋間距的位置上安放兩個光電元件,可 得到兩個相位差 90°的電信號,用反相器反相后就得到四個依次相差 90°的交流信號。同樣,在兩莫爾條紋間放置四個依次相距 1/4條紋間距的光電 元件,也可獲得四個相位差 90°的交流信號,實(shí)現(xiàn)四倍頻細(xì)分。其二、電 路細(xì)分。專用集成電路四倍頻專用集成電路 QA740210同時具有辨相和四倍頻細(xì)分的功能, 可將 兩路正交的方波進(jìn)行四倍頻后產(chǎn)生兩路加

6、、減計數(shù)信號,可送雙時鐘可逆 計數(shù)器進(jìn)行加、減計數(shù),也可直接送微型計算機(jī)(包括單片機(jī)進(jìn)行數(shù)據(jù) 處理。1、特點(diǎn):、數(shù)字化微分電路:4路微分信號脈寬由主頻周期決定,因此,是一 致的,而且可在很大范圍里方便地選擇。、臨界報警與過速報警兩檔速度提示:可在光柵運(yùn)動速度接近極限 值時給出臨界報警信息,以便操作者及時控制光柵運(yùn)動快慢。在速度超過 極限值時本電路將給出出錯信息。、絕對零位控制:絕對零位的設(shè)置將給操作者帶來許多方便,如故 障斷電后的重新定位等。本電路有“到絕對零位開始計數(shù)”和“到絕對零 位停止計數(shù)”,以及“與絕對零位無關(guān)”三種工作模式。、片選:本電路設(shè)有片選端,可以構(gòu)成多標(biāo)數(shù)顯系統(tǒng)。、 COMS

7、 工藝:輸入輸出的電壓電流與 4000系列 CMOS 及 LSTTL 電路 兼容。分類根據(jù)運(yùn)動方式分類直線位移傳感器原理:直線位移傳感器的功能在于把直線機(jī)械位移量轉(zhuǎn)換成電信號。為了達(dá) 到這一效果,通常將可變電阻滑軌定置在傳感器的固定部位,通過滑片在 滑軌上的位移來測量不同的阻值。傳感器滑軌連接穩(wěn)態(tài)直流電壓,允許流 過微安培的小電流,滑片和始端之間的電壓,與滑片移動的長度成正比。將傳感器用作分壓器可最大限度降低對滑軌總阻值精確性的要求,因為由 溫度變化引起的阻值變化不會影響到測量結(jié)果。LT 直線位移傳感器: 廣泛應(yīng)用于注塑、機(jī)床及機(jī)械加工等行業(yè) 無限分辨率 行程:50至 900mm 獨(dú)立線性度:

8、±0.05% 位移速度達(dá)到:5m/s、 10 m/s可選 工作溫度:-30至+100 多種電氣連接方式 保護(hù)等級:IP60(IP65可選角度位移傳感器根據(jù)材質(zhì)分類金屬膜傳感器、導(dǎo)電塑料傳感器、光電式傳感器、磁敏式傳感器、金 屬玻璃鈾傳感器、繞線傳感器。電位器式位移傳感器 它通過電位器元件將機(jī)械位移轉(zhuǎn)換成與之成線 性或任意函數(shù)關(guān)系的電阻或電壓輸出。普通直線電位器和圓形電位器都可 分別用作直線位移和角位移傳感器。但是,為實(shí)現(xiàn)測量位移目的而設(shè)計的 電位器,要求在位移變化和電阻變化之間有一個確定關(guān)系。電位器式位移 傳感器的可動電刷與被測物體相連。物體的位移引起電位器移動端的電阻 變化。阻值的

9、變化量反映了位移的量值,阻值的增加還是減小則表明了位 移的方向。通常在電位器上通以電源電壓,以把電阻變化轉(zhuǎn)換為電壓輸出。 線繞式電位器由于其電刷移動時電阻以匝電阻為階梯而變化,其輸出特性 亦呈階梯形。如果這種位移傳感器在伺服系統(tǒng)中用作位移反饋元件,則過 大的階躍電壓會引起系統(tǒng)振蕩。因此在電位器的制作中應(yīng)盡量減小每匝的 電阻值。電位器式傳感器的另一個主要缺點(diǎn)是易磨損。它的優(yōu)點(diǎn)是:結(jié)構(gòu) 簡單,輸出信號大,使用方便,價格低廉。霍耳式位移傳感器 它的測量原理是保持霍耳元件(見半導(dǎo)體磁敏元 件的激勵電流不變,并使其在一個梯度均勻的磁場中移動,則所移動的 位移正比于輸出的霍耳電勢。磁場梯度越大,靈敏度越高

10、;梯度變化越均 勻 , 霍耳電勢與位移的關(guān)系越接近于線性。霍耳式位移傳感器的慣性小、頻 響高、工作可靠、壽命長,因此常用于將各種非電量轉(zhuǎn)換成位移后再進(jìn)行 測量的場合。光電式位移傳感器 它根據(jù)被測對象阻擋光通量的多少來測量對 象的位移或幾何尺寸。特點(diǎn)是屬于非接觸式測量,并可進(jìn)行連續(xù)測量。光 電式位移傳感器常用于連續(xù)測量線材直徑或在帶材邊緣位置控制系統(tǒng)中用 作邊緣位置傳感器。傳感器市場發(fā)展前景咨詢公司 INTECHNOCONSULTING 的傳感器市場報告顯示, 2008年 全球傳感器市場容量為 506億美元,預(yù)計 2010年全球傳感器市場可達(dá) 600億美元以上。調(diào)查顯示,東歐、亞太區(qū)和加拿大成為

11、傳感器市場增長最快 的地區(qū),而美國、德國、日本依舊是傳感器市場分布最大的地區(qū)。就世界 范圍而言,傳感器市場上增長最快的依舊是汽車市場,占第二位的是過程 控制市場,看好通訊市場前景。目前,全球的傳感器市場在不斷變化的創(chuàng)新之中呈現(xiàn)出快速增長的趨 勢。有關(guān)專家指出,傳感器領(lǐng)域的主要技術(shù)將在現(xiàn)有基礎(chǔ)上予以延伸和提 高,各國將競相加速新一代傳感器的開發(fā)和產(chǎn)業(yè)化,競爭也將日益激烈。 新技術(shù)的發(fā)展將重新定義未來的傳感器市場,比如無線傳感器、光纖傳感 器、智能傳感器和金屬氧化傳感器等新型傳感器的出現(xiàn)與市場份額的擴(kuò)大。Linear displacement transducer, also known as t

12、he sensor, which is divided into inductive displacement sensor, capacitive displacement sensors, optical displacement sensor, displacement sensor ultrasonic displacement sensors, Hall-type displacement sensor. Inductive displacement sensor is a metal sensor is a linear device, powered on, the switch

13、 sensor surface will result in an alternating magnetic field, when the metal object close to the sensor surface, the metal in the vortex and absorb the energy of the oscillator, the oscillator output amplitude of linear attenuation, attenuation changes and then to complete the purpose of non-contact

14、 detection of objects.IntroductionInductive displacement sensor with no moving contacts from dust and other non-metallic work factors, and low power consumption, long life, can be used in a variety of harsh conditions. Displacement sensors are used in automated production line equipment, analog inte

15、lligent control.Displacement and position of objects in motion on the amount of movement and displacement of the scope of measurement is quite extensive. Usually small displacement strain, inductive, differential transformer, eddy current, Hall sensors to detect the displacement of a large common in

16、ductosyn, grating, capacitive, magnetic and other sensor technology to measure the gate. Grating sensors which are easy to achieve because of digital, high accuracy (currently the highest resolution up to nano-scale, anti-interference ability, no one reading error, easy to install, use and reliable,

17、 in machining, instrumentation and other industries Been increasingly widely used.PrincipleMetrological grating is the use of grating moire fringe phenomenon to measure the displacement. "Moore" For the original French Moire, which means the water ripple. French silk workers found when the

18、 two layers of thinsilk, stacked together, will have a ripple-like pattern hundreds of years ago; if the relative motion of thin silk, the pattern will move with it, this strange is the moire fringe pattern. Generally, as long as there is a certain cycle curve clusters overlap, they will produce Moi

19、re fringe. Grating in the practical application of measurement has two transmission gratings and reflection gratings; action principle can be classified according to their radiation grating and phase grating; according to their use can be divided into linear and circular gratings. The following exam

20、ple to be discussed transmission grating. Transmission grating engraved on a uniform that is parallel to the gate line engraved line, a line width for the moment, b is fracture width between the two groove, W = a + b as grating pitch. Currently used carved 10,25,50,100,250 per mm grating strips line

21、s. Moire fringe grating measured horizontal displacement, need two gratings. A grating as the main grating, its size is consistent with the measurement range; the other one is a very small, as instructed grating. To measure the displacement must be added in the main grating side of the light source,

22、 grating side of the instruction plus photoelectric receiving elements. When the primary grating and grating relative movement direction, the shading effect of leaving the grating Moiréfringe mobile, fixed grating in the direction side of the optical components, the light intensity changes into

23、 electrical signals. Since the limited size of the light source and diffraction grating effect, making the signal for the pulse signal.Signal ProcessingTo the principles identifiedIn practice, the displacement has two directions, that is, choose a direction, the displacement of the positive and nega

24、tive points, so with a determination of Moire fringe optoelectronic devices can not determine the direction of displacement. In order to distinguish the need to have / 2 phase difference of the two moiré fringe signals.SubdivisionWith the improvement of measurement accuracy, to pitch as a unit

25、can not meet the requirements, the need to take appropriate measures to be broken down on the Moire fringe. Subdivision is the so-called changes in the moiréfringe of a cycle, issued a number of pulses to reduce the pulse equivalent. If given within a period of n pulses, the accuracy can improv

26、e n equipment, and each pulse is equivalent to the original pitch of 1 / n. After the count of the sub-pulse frequency increased n times, so also called n multiplier. There are two commonly used subdivision method: First, the direct segment. The difference between the 1 / 4 position on the Moire fri

27、nge spacing placed the two optical components, get the two 90 ° phase difference signal, the use of four inverter followed by a difference of RP after 90 ° of the AC signal. Similarly, in the two moire fringe order of distance between the place four 1 / 4 fringe spacing of the optoelectron

28、ic components, are available to the exchange of thefour 90 ° phase difference signal, to achieve four interpolated. Second, the circuit is broken down. ASIC ASIC QA740210 quadrature phase and also has identified four segments of the function of frequency can be two orthogonal frequency square w

29、ave generated after four two-Luke, by counting the signal, can send even the clock reversible counter Add, subtract, count, can also be sent directly to micro-computer (including MCU for data processing. 1, features: , digital differential circuit: 4 Differential pulse width determined by the freque

30、ncy of cycles, therefore, is consistent, and can be easily in a wide range of choices. , criticality alarm and over-speed warning two speed Tip: You can limit the grating velocity when approaching the critical alarm information is given to the operator speed control in a timely grating movement. Fas

31、ter than the time limit in the circuit will give an error message. , absolutely zero control: absolute zero setting will bring much convenience operators, such as power failure after the re-positioning. This circuit has "absolutely zero to start counting"and"stop the count to the abso

32、lute zero"and"has nothing to do with the absolute zero" three modes. , Chip Select: This circuit has a chip select terminal, it can be multi-standard digital display system. , COMS process: input and output voltage and current with the 4000 series CMOS and LSTTL circuits compatible. C

33、ategories Classified according to the motion method Linear displacement sensor Principle: Function of linear displacement sensor is the linear mechanical displacement into electrical signals. To this effect, usually slide-set variable resistor the fixed part of the sensor, through the slider on the

34、rail to measure the displacement of different resistance. Steady-state DC voltage rails connecting the sensor to allow a small flow through the micro-ampere current, slip between the film and the beginning of the voltage terminal, and the length of vane movement. The sensor can be used as a divider

35、rails to minimize the total resistance of the requirements of accuracy, because the resistance caused by the change of temperature change will not affect the measurement results. LT linear displacement sensor: widely used in injection molding, machine tool and machining industry infinite resolution

36、Duration: 50 to 900mm Independent Linearity: ± 0.05% displacement speed: 5m / s, 10 m / s optional Operating temperature: -30 to +100 a variety of electrical connections Protection class: IP60 (IP65 optional Angular displacement sensor According to classified material Metal film sensors, conduc

37、tive plastic sensors, photoelectric sensors, magnetic sensors, metal glass uranium sensor, the sensor winding. Potentiometer displacement sensors which components will be through the potentiometer associated mechanical displacement into a linear or any function of the resistance or voltage output. G

38、eneral linear and circular potentiometer potentiometer can be used as a linear displacement, respectively, and the angular displacement sensor. However, to achieve the purpose of measuring the displacement potentiometer designed to require change and resistance change in the displacement of a defini

39、te relationship between. Potentiometer displacement sensors and the measured object can be linked to dynamic brush. Potentiometer caused the displacement of objects moving side of the resistance change. Reflect the change in resistance value of displacement, the increase or decrease the resistance t

40、hat the displacement direction. Usually pass on the potentiometer to supply voltage to the resistance change is converted to voltage output. Wirewound potentiometer wiper is moved due to its resistance to change turn resistance ladder, the ladder-shaped output characteristic was also found .If this

41、displacement sensor used in the servo system position feedback device, the excessive voltage can cause system oscillation step. Therefore, the production of the potentiometer should be to minimize the resistance of each turn. Potentiometer sensor is another major drawback is easy to wear. Its advant

42、ages are: simple structure, large output, convenient, low prices. Hall displacement sensor measuring principle is to maintain its Hall component (see semiconductor magnetic components of the excitation current constant, and make it in a uniform magnetic field gradient to move, then move the displace

43、ment is proportional to the output of the Hall Potential. The greater the magnetic field gradient, the higher the sensitivity; gradient more uniform, Hall electric potential and the closer relationship between the linear displacement. Hall of inertia displacement sensors, high frequency response, reliable, long life, so commonly used in all kinds of non-electricity and then converted into the displacement measurement occasions. Optical displacement sensor is based on the number of the measured object to bloc