Error Modeling,Identification And Compensation For RV Cycloidal Gear Based On Machining Test

RV reducers are increasingly used in industrial robots,and their core component cycloidal gears require precision grinding machines for finishing.In order to ensure its geometric accuracy,how to reduce the contour error of the cycloidal gear has always been a hot and difficult point.In order to improve the machining accuracy,error compensation based on machine geometry error is a commonly used technical method.However,most of the measurement of geometrical errors of machine tools is based on direct measurement.This type of method is complicated in operation and takes a long time in the whole measurement process,which is difficult to meet the requirements of simple and fast in actual production.In this paper,an error compensation method and experimental study of RV cycloidal gear contour error modeling and identification based on machining test and contour machining are presented.The main research work of this paper is as follows:1)The establishment of a geometric error model for a four-axis cycloidal gear grinding machine.By analyzing the geometric error characteristics of the linear axis and the rotating shaft of the four-axis cycloidal gear grinding machine,the relevant geometric error terms are summarized.According to the positional relationship between the axis and the axis,the characteristic transformation matrix between adjacent bodies is described according to the rigid body kinematics and multi-body system theory,and the geometric error model of the four-axis cycloidal gear grinding machine is established.2)Error modeling,separation and tooth shape compensation method for cycloidal gear profile based on machining test.The cycloid gear is processed by the grinding machine according to the actual machining process,and the geometric tooth profile is measured offline by a precision coordinate measuring machine.The error point modeling and separation of the cycloidal gear profile are realized by analyzing the measured point cloud data.According to the characteristics of the machining process,the contour error model of the cycloidal gear is established.A three-step error separation method is proposed: separation of workpiece clamping positioning error based on least squares fitting circle method;separation of geometric error of machine tool Y direction based on extracting the contour center line equation of each tooth contour;based on the contour between teeth and teeth Separation of the angular error of the machine shaft A extracted from the angle of the center line.A tooth shape compensation method for cycloidal gear based on grinding dynamics model is proposed.The tooth profile error is extracted based on the tooth profile error extracted by the cycloid gear tooth profile error separation method.According to the comparison of the tooth profile error before and after compensation,the effectiveness of the proposed machining test method for tooth profile compensation is verified.3)Experimental study on the separation and compensation method of the profile error of cycloidal gear based on the proposed machining test method.The machine geometry based on the machining test was verified by the identification of the geometric error of the three moving axes of the machine based on the multi-station measurement method of the laser tracker and the geometric error of the machine shaft based on the laser interferometer and its rotary axis calibration device.The feasibility of the error identification method.The effectiveness of the proposed tooth profile compensation method is verified by the separation of the actual processing of the cycloidal gear and the tooth shape compensation experiment.