Research And Design Of Automatic Test System For Synchro

In the field of aerospace and military industry,Synchro is a kind of high precision instrument,which is widely used in servo system and used to transfer angular displacement information.Its normal use can not be separated from high-precision performance testing.However,at present,the research on the testing system of synchronous machine is not perfect.Based on the practical requirements of aerospace enterprises,this paper aims at improving the test efficiency and precision,and makes a deep research on the high precision automatic test system and related theory of synchronous machine.The main work of this paper is as follows:Firstly,a set of automatic test system of synchro is designed.In order to realize the real-time detection of angle signal and the real-time processing,statistics and analysis of angle value,this paper presents a hardware and software architecture,including the testing platform of the lower computer and the user interaction software of the upper computer.In the lower computer part,because the angle signal of synchronous self-rectifying machine exists in the form of three-phase analog voltage,this paper designs an axis angle conversion and calculation circuit based on electronic ? servo control loop,and realizes the real-time conversion and calculation of digital angle.Since the synchro needs high precision and high stable excitation voltage,this paper designs the excitation power module based on DDS digital synthesis frequency technology,reaching the index of accuracy less than ±0.1% and stability less than 0.1%.In the upper computer part,in order to realize the collection,processing,display of test information and the automation of test process,this paper USES Labview virtual instrument technology to design the user interaction software system based on the producer/consumer architecture.This system by the defense department workers first measurement test center certification,measuring Angle error is less than or equal to ± 0.08 °,meet the demand.Secondly,the source of the system Angle error is analyzed,and the error is reduced from the hardware aspect.Based on the analysis of measurement principle and experimental data,it is determined that the error of Angle measurement mainly comes from sines and cosines signal amplitude mismatch,non-orthogonal phase,existence of harmonics and phase shift of relative excitation.In view of the above factors,this paper designs the voltage adjustment circuit,active second-order butterworth low-pass filter,phase shift circuit and phase lead/lag correction circuit,so as to further optimize the test system and improve the test accuracy.Finally,according to the characteristics of the system Angle error,the error is further reduced from the Angle of error compensation.In view of the high complexity of Angle measurement error in the test system,this paper further improves the test accuracy from the Angle of error compensation.After analyzing the least square fitting,table lookup error correction method,BP neural network algorithm and random forest algorithm,it is determined that the compensation algorithm based on random forest is the most suitable for the error compensation problem in this paper.In the end,this paper implements the system Angle measuring error control within the ± 0.01 °,effectively improve the system test accuracy.