Research On Measuring Method Of Gear Parameters Based On Machine Vision

Gear is an important part of mechanical transmission.Because of the inevitable errors in processing,the accuracy detection of gear is of great significance.Because of the low efficiency of traditional gear measuring instruments,they can only sample gears.Because of the advantages of non-contact,high precision and high efficiency,machine vision-based measuring methods have become the development trend of gear measuring technology.In this paper,a gear measuring system based on machine vision is studied,and the measuring method of gear parameters is designed.The research work includes:1.Design the gear measuring system.According to the detection requirements of gear parameters,a high-precision visual detection platform is built,and the light source system is designed.The imaging models of linear array camera 1 and linear array camera 2 are established respectively to complete the calibration of the visual system.2.The circle fitting algorithm for gear measuring system is studied.The Huber circle fitting algorithm studied in this paper divides the fitting points into confidence region and outlier region by threshold K,which resists the interference of outliers.The best fitting effect is obtained by iterative calculation using the step-size calculation strategy of dichotomy.The rule of threshold K value in Huber circle fitting algorithm is analyzed by simulation experiment.The Huber circle fitting algorithm is used to measure the top circle,root circle and inner circle of gear teeth,and the rationality of setting threshold K empirical value in application is verified by theoretical analysis.3.Design the measuring method of gear parameters.According to the geometric relationship,the runout of the top circle,the true roundness of the inner circle and the concentricity of the top circle and the inner circle are calculated.According to the geometric characteristics of common normal,the length of common normal is measured by polar coordinate transformation.Gear image after morphological processing can measure the value of surface measurement.Taking the measuring method of coordinate measuring instrument as reference,the measuring method of gear thickness is designed.4.The feasibility of the system is verified by experiments.Taking the eccentricity between the gear center and the rotary center of the rotary platform as independent variables,the conclusion that the eccentricity within 1 mm has little effect on the measurement results is verified.In addition,the repeatability of the measurement results of the gear measuring system is verified,and the reliability of the measurement system is further proved by comparing with the Three-coordinate Measurement values.