鞋楦数字化加工中高精度放码算法

HIGH PRECISION ZOOM ARITHMETIC OF SHOE LAST

鞋楦放码是鞋楦数字化加工的重要环节,决定了同系列不同尺寸鞋楦之间的相似度,最终关系到鞋楦生产质量。分析了传统机械靠模放码方法和鞋楦测头中心数据放码方法的原理,确定了放码误差的产生原因,由此提出一种高精度的鞋楦表面轮廓放码算法。该算法通过B样条偏置方法计算出鞋楦表面数据,由放码系数求得鞋楦放码后的极径增量,并通过矢量的旋转映射方法获得测点法矢方向的增量值,以得到精确的放码后鞋楦数据。仿真分析和实际应用验证了该方法的准确性。

As a key factor of shoe last numerical machining, zooming is the most important determinant which affects the similarity among the shoe lasts of same series with different size and which will ultimately determine the quality of the products. By analyzing the traditional process of zooming with mechanical explorator and the zooming principle of the data at the center of the measuring head, the major causes of the zooming error are discovered. An zoom arithmetic with high precision for shoe last machining is proposed. The zooming data of shoe last＇s surface are calculated by B-spline offsetting. The increment of polar distance after zooming can be calculated by using the zoom factor and the increment along the normal vector of the measuring point can also be calculated by rotation mapping of the vector. Finally, the accurate data of the shoe last＇s surface after zooming can be obtained. With simulation and experimental results, it is verified that the method discussed has high precision and high efficiency.