Method Of Testing Frequency Characteristics Research On Displacement Transducer

With the continuous development of electro-hydraulic proportional technology，Hydraulic valve has.higher and higher demand for performance requirements of itssensor,Especially the dynamical characteristics,which directly affects the dynamicalperformance of hydraulic valve, so it is very important to study the dynamicalcharacteristics of the valve with sensor.This paper use three-section-type LVDT in the high-frequency response proportionalservo as the research object, studied the test method of LVDT dynamical characteristics.Firstly, based on the work principle of LVDT, establish the equivalent circuit ofLVDT, and obtained the mathematical expression of output voltage of its the secondarycoil. Meanwhile,through analyse the total signal transfer process of LVDT, dynamicaltesting system of LVDT can be approximated as a linear time invariant system.Afterwards based on the control theory, The statical and dynamical performanceindex of LVDT is come up with, Select these method, such as the single sinusoidal testmethod, the frequency characteristic of FFT method and the frequency characteristics ofthe power spectrum method, the testing method of LVDT dynamical characteristics, andprove the feasibility of them using mathematical theory. Based on three kinds ofmathematical theory of method and based on the LabVIEW2009software platform,Prepared by testing program about the LVDT frequency characteristic.Finally, the LVDT hardware test platform of the static and dynamical characteristicsis constructed, tested the statical characteristics and frequency characteristic of LVDT,obtained its statical characteristics indicators--sensitivity and linear range, andfrequency characteristics--amplitude and phase frequency bandwidth. By comparingmathematical theory and test results of the three kinds of test methods of LVDTdynamical characteristic obtain that Three testing methods are basically consistentresults,and show The test results of LVDT frequency characteristic is correct, the systemdesign is reasonable, testing method are reliable.