The user requires that after the car clock shown is installed in the hole shown, the dial surface of the clock and the curved surface of the car reach a good fit. The realization method of curved surface fitting 3.1 Measuring feature points form a two-dimensional grid according to the shape of the accessory mounting hole. The intersection of the grid is the feature point to be measured. Measure the height coordinate value of each feature point according to the two-dimensional grid graph shown.
Design research analysis can be expressed by the following formula: x1=(1-t)2×0+2t(1-t)x1+t2x2(1)y1=(1-t)2y0+2t(1-t)y1+t2y2 (2) z1=(1-t)2z0+2t(1-t)z1+t2z2, find the value of t in the Bezier curve equation and substitute the Z coordinates of P0, P1, and P2 into the third equation of the above formula, The value of t can be calculated: t=0.5563. Calculate the Z coordinates of five intermediate points that cannot be measured. Since the Bezier curves of the 7 positions shown have the same properties, and the relative positions of the intermediate points relative to the two ends of the curve on each Bezier curve are the same, so The t-values of the seven Bezier curves are the same. After the t value is determined, the Z coordinates of the end points of each curve are substituted into the third equation of the above formula, and the height coordinates of the five intermediate points can be obtained respectively. The calculation results are shown in Table 1 below.
According to the measured coordinate values of the characteristic points, the Z coordinate values of the five intermediate points are calculated. Upper point 13.813.914.114.214.013.513.3 Middle point 14.915.115.515.715.615.215.0 Lower point 15.615.916.416.616.616.216.1 Note: The table is tilted The bolded data is the calculation result. After the surface is obtained, the height coordinates of the points shown in the table above are obtained, and then the three-dimensional fitting surface of the digital clock face is obtained by the masking method in Pro/E. The curved disc of the car clock is designed and manufactured by this method.
The method introduced in this article has been verified in the design of a car digital clock curved plate in a certain factory, and the method is simple, practical and reliable. If the accessory mounting holes are of other shapes, such as circular, elliptical, etc., this method is also applicable, except that the form of the two-dimensional grid of feature points is different.
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