Research On Spindle Radial Rotation Error Measurement Based On Rotating Target Trajectory

With the progress of manufacturing,the machining accuracy of machine tools is required to be improved gradually.As the core part of the machine tool,the spindle greatly affects the machining accuracy of the machine tool.The existing research results show that the higher the machining accuracy of the machine tool,the greater the spindle rotation error accounts for the total error of the machine tool.By accurately measuring the rotation error of the spindle,the machining accuracy of the machine tool can be evaluated,the health of the spindle can be evaluated,and the error motion of the spindle can be compensated to improve the machining accuracy.With the development of machining accuracy to micro-nano field,higher requirements are put forward for spindle rotation error measurement technology.Nowadays,although the rotation error measurement method based on error separation technology is widely studied and applied,this method has its shortcomings.During measuring,the artifact must be installed on the spindle,and the roundness error must be separated in the subsequent data processing.Therefore,it has great significance to study the spindle rotation error measurement method without roundness error separation.In this paper,based on the vision measurement system composed of industrial camera and telecentric lens,the measurement method of radial rotation error of high-precision spindle is studied.This method not only has the characteristics of low cost and high measurement efficiency,but also does not require roundness error separation.The main research contents of the paper are:(1)Target trajectory measurement modelBased on existing research,the measurement model of target trajectory method is established.The kinematics of the target point on the spindle end face is analyzed,and the formation mechanism of the target motion track is described.The target trajectory method is simulated and analyzed.The simulation results show that the target trajectory method is applicable to the detection of spindle rotating sensitive direction error specified in ISO 230-7:2015.The reasons and advantages of the target trajectory method without separation of roundness error are analyzed.(2)The construction of rotation error measurement systemThe visual measurement system is analyzed and established.The optical target is designed based on the measurement principle of target trajectory method.The Hessian Steger method is used to extract the centerline of the spot track formed by the rotation of the target.The experiment shows that this method can effectively calculate the centerline of the spot track,and the radial rotation error of the spindle can be calculated from the centerline of the spot track.(3)Spindle rotation error measurement experimentTaking the aerostatic spindle developed by the laboratory as the measuring target,and the industrial camera and telecentric lens as the measuring equipment,an experimental platform for measuring the rotation error is built.The spindle rotation errors at five different speeds are repeatedly measured.By analyzing the repeatability of the experimental data,the feasibility of the measurement method and the measurement system is verified.Finally,the synchronous error motion of the spindle is analyzed.