Study On The Measurement Method And Sensor Of Absolute Linear Displacement By Bilateral Sensing Units

With the development of automation and intelligentization in various fields,as a position feedback device,linear displacement sensors play an important role in many fields such as machinery manufacturing,aerospace,and petrochemicals.Inductive linear displacement sensor is widely used because of its high reliability,high stability and strong anti-interference ability.Since the movers of current inductive linear displacement sensors such as linear inductosyn,linear inductosyn,AMO,Zettlex LinTran and POSIC are generally installed only on one side of the stator,the measurement performance of the sensor is inevitably affected by assembly problems such as gap change and parallelism between the mover and the stator.In order to achieve high measurement performance,the installation and running track of the sensor often need to meet the demanding requirements.In view of this situation,this paper has carried out research on inductive linear displacement measurement methods with bilateral sensing units,and combined the absolute principle of linear displacement sensors with the principle of online self-calibration to develop an inductive linear displacement sensor with bilateral sensing units.It can perform absolute measurement and has online self-calibration function.The work presented in this paper are summarized as follows:(1)Based on the measurement principle of induction linear displacement sensor,linear displacement measurement method with bilateral sensing units was presented.This method can restrain the measurement error caused by the gap and parallelism between the movers and stator.(2)The linear displacement measurement method with bilateral sensing units and the influence of the gap and parallelism between the movers and stator on the measurement error of the method were verified by simulation.Then the structure of inductive linear displacement sensor with bilateral sensing units was designed.(3)The design of the electrical system in the experiment,the sensor prototype,and the experimental platform was carried out.The sensor prototype with the best measuring performance is obtained by comparison experiment,and the error source of the prototype was analyzed.It mainly has second-order error and fourth-order error.(4)According to the analysis of the error source,the structure of the sensor was improved,and the phase shifting circuit was designed to reduce the measurement error.Then,the measurement error of the sensor in a period is less than 13?m,and within the range of 0mm~288mm is less than 20?m.