Research Of High-steep Aspheric Based On Contact Coordinate Stitching On-machine Measurement

The conformal optical components are emerged to adapt to the development of high-speed aircraft and balance the aerodynamic requirements and stealth/optical performances of the aircrafts.The conformal optical components can improve the optical performance as well as the aerodynamic performance of the aircrafts greatly compared with the traditional optical components.Therefore,the conformal optical components has been widely used in the supersonic/hypersonic aircraft windows,thermal imager lens and optoelectronic systems of advanced weapons etc.The dome in front of missile is a typical conformal optical component,which plays an important role in military fields.The improvement of the machining accuracy of the conformal infrared optical dome that with steep geometry is closely related to the detection accuracy.Therefore,the research about on-machine measurements of aspheric surface form accuracy makes a very important significance in the stages of the rough/fine grinding and polishing.On-machine contact coordinate stitching measurement of high-steep aspheric surface is systematically discussed from the aspect of application background,domestic/international research status and development trend.Then,the accuracy of the data acquisition is improved by the computer MFC programming to synchronize the motion position of the machine and the output of the sensor,and an automatic control program as well as the host computer control software based on PMAC are established.In addition,the various measurement errors are analyzed to confirm the effect of pose error on the measurement data,such as the error of centralization and the rotation error of the sensor.Simulation was also conducted to investigated the influence of the measurement errors on the measured surface-shape.Besides,the radius of the sensor probe is the calibrated,and the influence of random errors such as repeated measurement accuracy and zero drift are analyzed.The principle of splicing measurement is developed,including the coordinate system transformation,error separation and data processing of the measurement system.Finally,a new splicing measurement method is proposed and its correctness and practicality are confirmed by the measurement experiments.This study validated the rationality of error separation theory and proposed the splicing theory by combining the theoretical analysis and experiments,and provided theoretical basis and practical experiences for on-machine measurement of high-steep aspheric in machining process.