Method for determining normal vector of wallboard curved surface

Abstract

The invention provides a method for determining a normal vector of a wallboard curved surface. According to the method, a theoretical normal vector of a wallboard curved surface is obtained by a numeral control system of an automatic drilling and riveting machine; and then, four range-finding sensors are used to measure coordinates of four characteristic points; and a secondary curved surface equation of the wallboard is fit based on coordinate optimization of the four characteristic points and a to-be-drilled riveting point, so that an actual normal vector of the to-be-drilled riveting point can be solved. According to the invention, a range-finding sensor mode is employed to carry out measurement and possible problems like interference and the like are eliminated, wherein the problems are caused by contact measurement. Besides, a secondary curved surface optimization fitting is utilized; and the solution efficiency is high and the speed is fast. In practice, it only takes 0.047 seconds to measure and determine a normal vector of single drilled riveting point by using a complied MATLAB program and there is little time consumption; and normal vectors of lots of different drilled riveting points on a same wallboard can be rapidly and accurately measured.

Description

technical field [0001] The invention relates to the field of mechanical processing, in particular to a method for determining a normal vector of a curved surface of a wall plate. Background technique [0002] When performing automatic drilling and riveting on workpieces such as aircraft siding, the CNC system of the automatic drilling and riveting machine is processed according to the theoretical model of the siding. In fact, although the tooling and siding are positioned according to the theoretical position, the bracket will deflect as a whole under the action of gravity, the deformation in each direction will change dynamically when the bracket rotates, and the forming of the rivet pier head will cause the siding These effects will cause the actual panel clamped on the bracket to deviate from its theoretical position, and then the external normal vector of the riveting point will always deviate from the theoretical normal vector. Such deviation will affect the rivet The ...

AI Technical Summary

Problems solved by technology

The triangular patch method is widely used, but this method does not have strict mathematical reasoning or physical background, and more is to calculate the normal vector of each triangular patch by adjusting the weight value, and judge the pros and cons of the algorithm according to the calculation results ;Adopt the cumulative chord length cubic spline parameter curve, first find the tangent vectors in two directions at the discrete points, and then get the normal vectors at the discrete points through the cross product operation, but this requires a large number of coordinate values ​​of the discrete points. low efficiency

Due to the limitations of measurement technology, work efficiency and the mechanical structure of automatic drilling and riveting equipment, in the actual automatic drilling and riveting process, it is impossible to collect a large number of data point coordinates on the surface of the wall panel, which makes this method lose the premise of application

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