Variable-interval self-adaptive measuring point-searching aircraft panel normal vector determination method

Abstract

The invention provides a variable-interval self-adaptive measuring point-searching aircraft panel normal vector determination method, which can utilize the equicurvature integration method to self-adaptively search measuring points and interpolate two cubic B-spline curves on the measuring points according to the theoretical mathematical model of a panel, so as to determine the normal vector of the curved surface. Compared with the conventional method, the method utilizes the beneficial mathematical parameters provided by the theoretical mathematical model of the curved surface of the panel and adopts the equicurvature integration method to search the measuring points, thus ensuring that the density of the measuring points can be increased or decreased as the curvature of the curve is increased or decreased, the precision of solving the normal vector of the curved surface of the panel is increased by optimizing the distribution of the positions of the measuring points, the solution result can be used for guiding automatic drilling and riveting equipment to drill and rivet the panel, can be used in the analysis and estimation of panel deformation, and as a basis for the detection of the shape of the panel, the method is significant for the guarantee of aircraft panel-machining quality.

Description

technical field [0001] The invention relates to the technical field of measurement and detection, in particular to a method for determining the normal vector of an aircraft wall plate by adaptively searching measurement points with variable spacing. Background technique [0002] Automatic drilling and riveting technology is mainly used in the processing of aircraft panel parts. Among them, the normal accuracy of the wall plate drilling directly affects the aerodynamic shape of the aircraft and the safety performance of the component structure. The key technology lies in how to use the limited measurement points on the wall plate to determine the normal vector at the drilling point. The existing normal vector solution method is generally to select some adjacent measurement points around the point to be measured, and then use plane, curve or surface fitting to calculate according to the topological shape of the measured values ​​of these points, such as Ruey-Tsung Lee, etc. T...

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Problems solved by technology

The existing normal vector solution method is generally to select some adjacent measurement points around the point to be measured, and then use plane, curve or surface fitting to calculate according to the topological shape of the measured values ​​of these points, such as Ruey-Tsung Lee, etc. The 9-point 3×3 non-standard quadratic shell proposed in the literature Calculation of the unit normal vector using the cross-curve moving mask method for probe radius compensation of a freeform surface measurement (Measurement, pp469-478, 2010 (43)) Zier surface method and 5-point, 9-point non-standard quadratic Bézier curve interpolation method, Daoshan OuYang et al. in the literature On the normal vector estimation for point cloud data from smooth surface (Computer-Aided Design, pp1071-1079, 2005( 37)), the point cloud estimation method proposed by Yi Chuanyun et al. in the literature "Normal Vector Solution of Digitized Surface" (Journal of Huazhong University of Science and Technology, pp49-51, 2002, 30(8)) The accumulated chord length cubic parameter Spline method, etc. These curve and surface fitting methods can obtain better fitting results, and they can solve the normal vector of any space surface with high precision and strong universality, but the calculation of solving the normal vector of the wall panel surface is more complicated. And the above method to solve the normal vector needs to obtain a large number of measurement points on the actual surface

In terms of solution efficiency, such as the data acquisition of the three-point fast leveling method proposed by Qin Xiansheng et al. The amount is small, the calculation efficiency is high, and it is suitable for solving the normal vector of large-scale and small-curvature surfaces, but the accuracy of solving the normal vector of large-curvature wall panels is low

[0003] In addition, the selection of measurement points in the above method is fixed, and the distance between measurement points does not change with the change of the surface of the wall panel, and the selection rules of measurement points are often based on experience, which is out of touch with the theoretical mathematical model of the surface of the wall panel, so that the theoretical mathematical model guides the measurement. The surface normal vector aspect loses its application

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