Research On Error Analysis And Compensation Technology Of Non-contact Spherical Coordinate Precision Sphericity Measurement

Spherical parts are widely used in precision machinery,apparatus and instruments,aerospace equipment and other fields,and their precision is becoming higher and higher.For example,in gyroscope and precision bearings,the precision of spherical components directly affects the working quality of the whole instrument.The sphericity of high precision spherical parts is an important standard for evaluating parts.The existing sphericity detection techniques are mainly contact measurement,and there are many difficulties for the measurement of more than half of the sphere,and it is difficult to realize high precision and high efficiency three-dimensional detection of the over hemispherical surface,which restricts the wide application of the sphere parts and the development of the technical field.Therefore,the in-depth study of high precision sphericity measurement technology has important theoretical significance and engineering application value.A non-contact spherical coordinate measurement method is proposed for the problem of high precision sphericity measurement.The error factors that affect the measurement precision of the sphericity are analyzed theoretically.The error compensation method is established for the main geometric error factors,and the related experimental tests are carried out.A precise measurement model of spherical coordinate measuring system is established.According to the measuring principle and structure of spherical coordinate measuring system,twenty geometric errors that affect the measurement precision of the system are analyzed.Based on the quasi-rigid body hypothesis,the accurate measurement model of the system with twenty geometric error factors is established by the homogeneous coordinate transformation.Then the law of each geometric error to the measurement precision of the system is quantitatively analyzed.The results show that the six displacement geometric errors of the rotating axis and the system assembly errors are the main factors that affect the measurement precision of the system.At the same time,the reduction of the eccentric error of the measured ball is beneficial to the improvement of the measurement precision of the system.The geometric error compensation method of spherical coordinate measuring system is proposed.The rotary error separation technology is studied.The rotary error measurement scheme and phase by phase error compensation method based on the reverse method are designed.The rotation error of the spindle is accurately obtained through the data processing method of the elimination of average and primary harmonics from the standard ball measurement data,and the influence of the standard ball eccentricity error on the measurement precision of the rotation error is analyzed.The result shows that the data processing method can separate the spindle rotation error well in the case of small eccentricity error.For the seven assembly errors compensation problem,a calibration method based on high precision spherical target is proposed,the calibration model is established and the calibration principle is analyzed,and the nonlinear optimization is used to identify the error parameters in the calibration model.The influence law of the target ball eccentricity on the calibration precision is analyzed.The seven error parameters solving problems are transformed into five error parameters solving problem by combining the calibration model and the system assembly and sensor characteristics.The influence of the random error amplitude and calibration data measurement times on assembly errors calibration precision is analyzed.The result shows that the calibration method can accurately identify the assembly error of the spherical coordinate measuring system and the eccentric error of the ball,which lays a foundation for the further realization of the high precision sphericity measurement.The experiment of sphericity error compensation is carried out,and the high-precision non-contact three-dimensional coordinate measurement is realized.Based on the experimental platform of the spherical coordinate measurement system,the error measurement experiment and the assembly error calibration experiment are carried out.Then the sphericity measurement experiment is completed.By comparing the sphericity measurement results before and after the error compensation,the correctness of the mathematical modeling and error compensation method is verified.At the same time,the measurement precision of the sphericity is better than that of 0.639?m.It shows that the non-contact spherical coordinate measurement method proposed in this paper can realize the high precision measurement of the sphericity after error compensation.