基于泽尼克多项式系数的大相对孔径表面超精密车削误差的补偿方法

超精密车削误差补偿是提高超精密车削工艺水平的关键技术。首先对超精密车削中的各种误差进行了简单的分析与归纳,指出刀具刃口几何形状误差与机床导轨非线性误差具有相同的表现形式,可以通过车削零件的面形检测结果进行综合补偿。然后,提出了一种根据干涉仪检测结果对上述误差进行高精度补偿的方法,并进行了理论推导。最后的实验结果证明:基于面形误差泽尼克多项式球差及高级球差系数(最高到36项系数)对国产刀具刃口(波纹度误差大于0.2μm)与机床(Nanotech UPL250)系统误差进行综合补偿的方法正确而高效,仅3次补偿循环,即可使一大相对口径实验球面件的面形误差收敛到PV=0.24λ,rms=0.021λ,符合理论推导及计算机模拟的分析。

Compensation method for ultra precision turning error of high relative aperture surface based on coefficients of Zernike polynomial

Compensation of ultra precision turning error is the key technology for development of ultra precision turning process.Firstly,normal diamond turning errors were analyzed and generalized,which showed the geometrical form errors from diamond tool and nonlinear form errors from machine kinematics axis′s had the same format,and both of them could be compensated according to the measurement result of surface shape after diamond turning.Then,a precise compensation method according to measurement result from digital interferometer was proposed,and theoretical calculation related with this compensation method was deduced.The correction of such turning errors was done based on coefficients which represented spherical error and high order spherical error(up to thirty six terms) of Zernike polynomial.In the end,results from turning experiment by home made diamond tool(waviness of more than 0.2 μm)and Nanotech 250 UPL prove the new compensation method′s effectiveness,with high accuracy(PV=0.24 λ,rms=0.021 λ) and fast speed of error convergence(three compensation cycles),which is agreed with predictive analysis.