Research On Motor Speed And Vibration Measurement Based On Fabry-Perot Interferometry

With the development of various industrial applications,the demand for motors is increasing.The motor test and measurement have gradually attracted the attention.We need to obtain speed and vibration signal by detecting motor.So we judge the quality of the motor.And it finally give the further improvement target and direction of the motor to be detected.Finally we give the tested motor further improvement goals and direction though testing motors.So the motor test is very important in the development of a new motor and on the mass production and repair of the motor.This subject mainly studies the simultaneous measurement of speed of the double motors though the all-fiber measurement structure based on Fabry-Perot interference.Meanwhile speed and vibration of the motor can be monitoring though the Fabry-Perot interference.This paper solves the problems that single light source cannot be used to measure multi-motor speed.And this paper solves the problems that single light source cannot be used to measure motor vibration and speed parameters at the same time.We propose an all-optical fiber measurement structure based on Fabry-Perot interferometry principle to realize simultaneous measurement of the speed or velocity and vibration of the double motors.The all-fiber structure has many advantages which can better cope with the harsh environment when applied to the motor measurement.The method can be extended to the new motor velocity measurement and vibration survey meter.First,I study the development trend of motor vibration detection.Though analyzing and comparing non-contact optical measurement at home and abroad,I fully prove the advantages of the all-fiber measurement structure based on Fabry-Perot interference.Secondly,I’m going to analyze the theory of Fabry-Perot interference.I determined that the interference theory can be applied to the measurement of motor speed and vibration by deducing the theoretical formula for processing the autocorrelation algorithm method of speed signal and the multiple Hilbert transform of vibration signal.This provides the basic theoretical support for the measurement of motor speed and vibration based on Fabry-Perot interference.At the same time,analyze and compare the processing methods of interference signals.The advantages of using autocorrelation algorithm for processing motor speed signal and using multiple Hilbert transform for vibration signal of motor bearing housing are obtained.Then,based on the analysis of the above methods,the speed measurement of double motors based on the Fabry-Perot interference is proposed for multi-motor application systems such as the vibration fault simulation test bed of double-rotor aeroengine,the stepless speed coupling transmission test bed of double motors.The measurement method uses a distributed feedback laser.The laser via the single-mode fiber coupler,and then respectively through the circulator.Two beams of light directly on the surface of the motor shaft,respectively.When the motor shaft moves for a period,the velocity signal is carried out though autocorrelation calculation.And the running speed of the two motors is obtained in the meantime.It solves the problem that multiple light sources are needed when the speed of multiple motors is measured simultaneously,and realizes the simultaneous measurement of multiple motors by a single light source.Finally,in view of the motor vibration detection at the same time,the speed of the motor must meet the requirements of the corresponding values.I put forward the method based on the Fabry-Perot interference to test motor vibration and speed at the same time.We establish a theoretical model to preliminary estimate of the experiment,then achieve the simulated experiment.This method can be verified by the measurement experiments.The light can be divided into two beams of light.A light vertically irradiate on the surface of motor shaft.The other the light immediate illuminate is on vibration motor bearing surface.It will be treated as mixed signal decomposition,decomposition speed signal is obtained by autocorrelation algorithm processing speed information of the object.The vibration signal accomplish reconstruction of vibration displacement through multiple Hilbert transform algorithm processing.It solves the problem of measuring the motor speed with the instrument when detecting the vibration of the motor.