Flatness error evaluation method based on orthogonal experiment

A flatness error evaluation method based on an orthogonal experiment includes the steps: firstly, measuring and acquiring measured point coordinates on a measured plane; secondly, determining an initial reference plane according to three edge points in a measured point, transforming a coordinate system, enabling the initial reference plane to be parallel to an xoy plane and pass a coordinate origin, creating a two-parameter three-level L9 orthogonal table, calculating nine flatness values under different a and b according to a flatness calculation method, finding out a flatness minimum point, creating a new orthogonal table by taking the point as a center and narrowing the value range of a and b by half, repeating calculation and comparison until the search range of a and b is narrower than a set requirement or repeatedly iteratively calculated minimum flatness is no longer changed, stopping search and outputting flatness errors and corresponding plane parameters. Values of a and b in an ideal reference plane z=ax+by are within [-1, 1], a minimum flatness error value is an optimal value, and the flatness error and the plane parameters meeting a minimum area can be accurately calculated.