Transmission Error Measurement And Analysis For Cylindrical Gears Based On Digital Image Correlation

Transmission error is one of the main causes of vibration and noise in gear transmission.Transmission error can not only directly reflect the working state of gear transmission,but also can be used to extract the geometrical errors of gear.Therefore,the measurement of transmission error is of great significance to optimize the gear design,reduce vibration and noise,and eventually improve the transmission performance of gear.Digital image correlation is a non-contact,full field,highprecision optical measurement method,which is widely used in the measurement of displacement and strain in various engineering fields.This thesis gives exploits the advantages of the digital image correlation technique,regards it as a high-precision angular displacement sensor.By combining with the rigid body motion theory,this work develops a transmission error measurement method based on digital image correlation,and verifies the effectiveness of this method through simulations and experiments.The main findings of this present work are as follows:(1)The optical measurement method is developed for the motion dynamics of gear pair.According to the theory of rigid body motion,the coordinate change of the mark points on the rigid body is transformed into the translation matrix and rotation matrix of the gear pair,and then the direction vector and rotation angle of the rotation axis are calculated.The digital image correlation is successfully applied to measure the motion of the gear pair,as justified by the simulated experiment.(2)A schematic procedure is established for processing and analyzing the transmission error signal.Firstly,Butterworth filter is used to process the original mixed transmission error signal with low-pass filter to remove the high-frequency noise;secondly,the blind separation algorithm is applied to separate the transmission errors of large and small gears from the mixed transmission error signal.Finally,according to the principle of overall error of gear,a kind of filtering methods is used to extract the gear geometrical errors from the transmission error signal.(3)The transmission error measurement method is verified by an experimental setup.According to the proposed measurement method,the dynamic motion of the gear pair is measured by the digital image correlation.The transmission error and also axis parallelism error of gear pair are calculated.Then the transmission error signal is processed and analyzed,and the eccentricity and runout,pitch deviation and tooth profile deviation of the gear are extracted.Besides,the influence of working conditions(e.g.,rotational velocity,torque)on the transmission error is analyzed.The obtained results in this work are valuable as it provides a new way for noncontact error measurement of the gear transmission,even when the gearbox is in the operating conditions.