Research On Sensing And Rotating Axis Error Separation Technology For Large Curvature Surface Measurement

Various high-precision surface components are widely used in national defense,aerospace,information technology and other fields.A variety of complex surface elements in is also widely used in daily life,many have a large curvature.The manufacturing of these components is inseparable from high-precision measurement,it can be said that the current manufacturing accuracy is limited by the measuring accuracy.In order to construct a large curvature surface profile measuring instrument,the instrument principle,measurement method and some key technologies involved are deeply studied.In order to achieve accurate and efficient Non-contact measurement of curvature surface profile,a single-axis normal-tracking measuring method based on differential confocal principle is proposed,which has high resolution and high signal-noise ratio.The factors that affect the system resolution are analyzed;the influence of tilt on differential confocal detection is studied when the incident light is a Gaussian beam;the optimal size of pinhole offset and pinhole size when beam is tilted is verified by theoretical model and experiment.The sensing system is established,the working principle and constitution of the system are introduced,experiments show that the system can track the measured surface well,the axial resolution of the system is better than 5 nm.The system can be used for large curvature of the surface contour measurement when combined with a high precision laser interferometry system.The method and technique of single-step spatial rotation error separation technique for large-curvature surface profile measurement is studied.The theoretical analysis and simulation experiment of the error separation are carried out according to the mathematical tools such as discrete Fourier transform and harmonic analysis.Based on this error separation technique,the error separation experiment of an air-bearing table is carried out.The axial and radial errors of the rotary shaft are successfully separated by the experiment.It provides a technical basis for real-time separation of errors introduced by the rotary spindle in the measurement of the large curvature surface profile.