A Radius Surface Compensation Method of Probe Radius Surface of Blade Curved Surface Contact Scanning Measurement

Abstract

The invention discloses a method for compensating the radial surface of a curved surface of a blade by contact scanning and measuring a probe, which belongs to the field of detection of complex curved surfaces of engine blades. The three-dimensional dense scanning data of blade-like curved surface parts is obtained through a multi-axis linkage coordinate measuring machine, and the original linear array scanning point set is topologically segmented to establish a regular area array data structure; the method of constructing a tensor product surface is used to establish a NURBS interpolation fitting surface, The unit normal vector at the interpolation point of the surface is obtained by solving; for the surface with gentle curvature changes of the leaf basin and the back of the leaf, the surface scanning point set is offset inward along the direction of the normal vector by the radius distance of the probe to obtain the three-dimensional compensation result of the surface; For surfaces with sharp curvature changes at the leading and trailing edges, the offset-compensated data set is constructed as a polygonal grid, and the smooth data point set obtained by intersecting the grid data model with multiple blade profiles represents the final compensation for the sharply changing surface result. The invention fully combines the curvature change characteristics of the curved surfaces of blades, and takes into account the balance of compensation accuracy and efficiency.

Description

technical field [0001] The invention belongs to the field of digital detection of complex curved surfaces of engine blades, and in particular relates to a compensation method for the radius surface of a measuring head in contact scanning measurement of curved surfaces of engine blades. Background technique [0002] The blade is a representative of the key precision parts of the engine, and its processing quality directly affects the aerodynamic performance of the engine. Therefore, the detection of its processing quality has become an important means to ensure the design compliance and reliability. At present, the final inspection and acceptance of the blades of domestic engine OEMs is mainly completed by high-precision coordinate measuring machines. However, for contact measurement, it inevitably brings about the compensation of the probe radius. At present, the mainstream blade detection mode mainly adopts the contour section method to measure, and then performs radius c...

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Problems solved by technology

[0004] In view of the deficiencies of the above-mentioned existing methods, the purpose of the present invention is to provide a method for compensating the radius surface of a probe for contact scanning measurement of complex curved surfaces of engine blades, which is used to solve the problem of measuring probes for contact scanning point cloud data of multi-axis coordinate machines with complex curved surfaces. The problem of three-dimensional accurate compensation of the radius is to realize the accurate acquisition of the surface profile data at the contact point of the measuring ball, thereby improving the accuracy of the measurement and evaluation of the blade surface profile parameters

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