Analysis And Experimental Research On Machining Error Of High-precision Star-sensitive Bracket

Star sensor is a high-precision space attitude measurement device which takes stars as reference frame and stars as working objects.It can provide accurate space position and reference for satellites,intercontinental strategic missiles,spaceships and other aerospace vehicles by detecting and settling stars at different positions in the celestial sphere.It also has autonomous navigation ability like inertial gyroscope and has important application value Value.Star sensor is the “thousand mile eye” of satellite.The support structure of star sensor,star sensor bracket,ensures the stability and normal operation of star sensor.The machining accuracy of star sensor bracket is particularly important.In this paper,the machining errors of high-precision star sensor bracket are analyzed.The main machining errors include machine tool manufacturing error,radial runout error,tool stability error,tool length accuracy error and tool spindle rotation error.In addition to the spindle rotation error needs to be compensated by NC programming,other errors can be reduced by corresponding measures.The compensation strategy of tool rotation error in high-precision star sensitive machining process is modeled and analyzed,and the machining error of five axis machine tool is compensated according to the tool error compensation method of three-axis machine tool.Compared with the three axis machine tool,five axis machine tool not only needs to compensate the tool position,but also needs to compensate the optional angle of the tool.The 125 pnas specimen was designed according to the shape characteristics of the star sensor bracket,and the corresponding error reduction measures were taken according to the corresponding processing error causes.After the basic frequency of the star sensor support is obtained through simulation test,the processing parameters are set to avoid resonance;the cushion block is designed to make up for the process system error caused by the machine itself;the error caused by the sample clamping is reduced by measuring the deformation of the blank after clamping;the error caused by the length and instability of the tool is reduced by the tool setting instrument and the cold tool holder,The 125 pnas specimen was processed,and the machining results were measured and analyzed;the tool spindle bus deflection angle and tool position in the processing process were measured,which laid the foundation for the subsequent high-precision star sensor bracket processing test.Under the above measures to reduce the machining error,the high-precision star sensor bracket is processed,and the NC programming and error compensation are carried out according to the tool deflection angle and tool position measured by the test.The processingresults of the high-precision satellite sensor bracket are measured.The measurement and analysis results show that the machining of the high-precision satellite sensor bracket meets the accuracy requirements.