环形子孔径拼接检测中机械误差的分离

为减少环形子孔径拼接干涉检测中机械误差对检测结果造成的影响，分析环形子孔径拼接过程中机械误差作用分量的表现形式，提出了分离机械误差的全局优化的环形子孔径拼接方法。分析根据波像差理论建立的机械误差分离数学模型，然后将其应用于避免误差传递和累积的全局优化的拼接方法中，并提出利用光线追迹的方法在拼接之前除去理想非球面波前与参考球面波前的差别。应用分离机械误差的拼接方法对口径为75mm、顶点曲率半径为100 mm的抛物面面形进行检测，得到的面形峰谷值误差为0.05，均方根值误差为0.003，验证了该拼接方法可有效分离环形子孔径拼接中的机械误差。

Separation of mechanical error in annular subaperture stitching interferometry

Due to the relative posture of each subaperture measurement is not known exactly, there is some ambiguity when the individual annular subapertures are combined into a full aperture map. To reduce this ambiguity resulted from mechanical errors, a global optimization algorithm separating mechanical errors was proposed. This algorithm established a mathematical model for separating mechanical errors based on wavefront aberration theory, and used ray tracing to eliminate the difference between ideal aspheric wavefront and reference spherical wavefront in every annular subaperture. Based on the global optimization algorithm which could abstain error transfer and accumulation， and each measured subaperture phase subtracted corresponding calculated difference firstly, and then these subaperture phases were stitched into a full aperture map by this algorithm containning mechanical error separation. A paraboloid with aperture of 75 mm and vertex radius of 100 mm was tested by annular subaperture stitching interferometry, the error of peak-valley was 0.05 λ, and the root-mean-square error was 0.003 λ. Results indicate that the global optimization algorithm can effectively separate and compensate mechanical errors.