Research On The Measuring Technology In Machine Of Large Gear Rotary Center

In general,gears larger than 500 mm in diameter are called big gears.As the significant part of the large machinery equipments,big gears are widely used in mining machinery,drilling,large engineering machinery and large ships,whose quality,performance and longevity have a direct effect on the entire economic and technical index.Nowadays,the world's big gear manufacturing technology are constantly improving and the varieties and specifications is constantly expanding,demanding higher requirements for testing technology and measurement instruments and promoting the development of this technology at the same time.At present,the measurement of large gears mainly depends on the measuring system of gear measurement center,three-coordinate measuring machine and laser tracking gear.The precondition of these measurements is the measurement of the large gear turning center.With the application of sensors and advanced manufacturing technology in the field of gear measurement,machine vision in gear measurement systems has a good prospect.The noncontact measurement based on machine vision technology has some advantages: CCD camera for image acquisition gear Easy data storage,management and more intelligent;at the same time cannot be achieved in contact or measurement conditions harsh conditions,you can achieve high-precision measurements.In this paper,the measurement method of the rotation center of large gear based on machine vision is studied.The main work includes the following aspects:(1)Based on the understanding of existing on-machine measurement technology of large gears,a measurement method based on machine vision for the rotation center of large gears is proposed.Two round measurable circular patches in the radial direction of the upper end face of the bull gear is fixed.Due to the limited field of view of the CCD camera,In the process of the rotation of the circular patch by the large gear,two cameras to perform image acquisition on the circular patch are used.(2)Gaussian filtering to denoise the image of the patch point is used.Then the sub-pixel edge extraction algorithm based on Gaussian integral curve is used to obtain the edge curve of the patch,and then the center coordinates of all the patches are obtained.(3)A least squares fitting method based on the constraint of constant radius difference was proposed.The theoretical model of the least square fitting method based on the fixed radius difference constraint was established,and the corresponding error analysis was performed.The feasibility and reliability of the method were verified by simulation experiments.Then this method to deal with the coordinates of all patch center points to get the center of rotation of the large gear is used.