Analysis And Measurement Of Rotation Angle Error And Rotation Accuracy Of Rotary Axis

As a key part of precision machinery and instruments,the rotary axis has a very important role in positioning and transmission of power in the entire mechanical equipment.The rotation error of the rotary axis has a directly impact on the accuracy level of precision machinery and measurement equipment.In the study of improving the rotation error of the rotary axis,the error compensation technology is a relatively simple implementation method proposed in recent years,and it can improve the accuracy of the rotary error at a lower cost.Therefore,the measurement of the key error in the rotation error of the axis and the establishment of the error compensation model are important ideas for improving the overall system accuracy.There is a six-degree-of-freedom error in the rotary motion of the rotary axis: three displacements and three angles.At present,most studies of the rotary error measurement are performed on a rotary spindle and a rotary table.However,it is rare to study the rotary error of a rotating shaft such as a mandrel driven by clamping device or a center structure.This paper analyzed the error of the rotation angle of the rotating mandrel in the gear measuring machines and established the corresponding error model.By using the gear measurement center,the influences of the coaxial concentricity errors of the upper and lower tips,rotation state of the lower tip and rotation angle error of the spindle on the rotation angle error of the rotating mandrel were analyzed.Furthermore,the corresponding measurement experiment was carried out on the laboratory Mahr891 E gear measurement center.The experimental results show that,when the coaxial deviation between upper and lower tips is 10 μm and the radial runout of the lower tip is 1.6 μm,the angular error between mandrel and spindle is within ±5 arcsec.When the error compensation model is used,the error is reduced to within ±2 arcsec,and this error model have good compensation effects which was experimentally verified on the gear measurement center.In addition,this paper analyzed the influence of the rotary error of the rotary axis on the measurement angle error of the encoder.A method of calculating the radial runout error of the rotating shaft was proposed by measuring the rotation angle error using a double read head circle grating.An experimental devices was built using Renishaw’s round gratings,small turntables.The eccentric error of the installation of the circular encoder disc generated during the experiment was measured and separated.Finally,the experimental results were compared with the traditional measurement method.It was found that the method of measuring the spindle rotation error using the double-reading head circle grating was practical and feasible.The measurement method proposed in this paper can not only achieve long-term and high-precision measurement accuracy,but also realize real-time measurement.