基于磁敏角度技術(shù)的拉線式位移傳感器的設(shè)計(jì)與應(yīng)用

摘 要:介紹MLX90316的結(jié)構(gòu)和特性，設(shè)計(jì)以LPC2136為CPU，MLX90316為位置反饋的拉線式位移傳感器，給出了基于MLX90316的位移檢測策略，并詳細(xì)分析了接口電路原理圖和編程原理。該傳感器具備一路RS 485通信鏈路和一路基于PWM可調(diào)電流輸出。試驗(yàn)證明，該傳感器克服傳統(tǒng)拉線式位移傳感器的易磨損、分辨力差、阻值偏低、高頻特性差等缺點(diǎn)，提高了測量精度。

關(guān)鍵詞:MLX90316; 磁敏角度技術(shù); 位移傳感器; LPC2136

中圖分類號:TN919; TP29文獻(xiàn)標(biāo)識碼:A

文章編號:1004-373X(2010)15-0136-03

Design and Application of Guyed Displacement Sensor

Based on Magnetosensitive Angular Technology

SU Yu，LU Yin-ju

(School of Information Engineering， Zhongzhou University， Zhengzhou 450044， China)

Abstract: The structure and characteristics of MLX90316 are introduced. A guyed displacement sensor which takes LPC2136 as CPU and MLX90316 as position feedback component is designed. The displacement detection method based on MLX90316 is presented. The schematic diagram of interface circuit and programmming principle are analyzed in detail. This sensor has a RS485 communication link and adjustable current output based on PWM. The experiment demonstrates that the shortcomings of traditional guyed displacement sensor such as rapidly wearing， weak resolution， lower resistance and bad high-frequency characteristics are overcome， and the measurement accuracy is improved.

Keywords: MLX90316; magnetosensitive angular technology; displacement sensor; LPC2136

0 引 言

傳統(tǒng)的拉線式位移傳感器采用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[1]。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[2]。但是，為實(shí)現(xiàn)測量位移目的而設(shè)計(jì)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，把電阻變化轉(zhuǎn)換為電壓輸出。傳統(tǒng)的拉線式位移傳感器由于其電刷移動時(shí)電阻以匝電阻為階梯變化，其輸出特性亦呈階梯形[3]。如果這種位移傳感器在伺服系統(tǒng)中用作位移反饋元件的時(shí)，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。同時(shí)，電位器式傳感器的另一個主要缺點(diǎn)是易磨損、分辨力差、阻值偏低、高頻特性差，從而導(dǎo)致測量精度的下降。……