多击痕轮廓最小外接圆法测量击针偏心度

针对两个以上的击痕会有重叠不利于单个击痕轮廓圆拟合的问题,提出了一种通过测量多个击痕整体轮廓的最小外接圆来实现火炮击针偏心度检测的方法。首先,对药筒进行单次击发,获得底火上单个击痕的图像,并拟合出单个击痕的圆半径;然后,再对药筒进行不少于3次的击发,任意两次击发之间药筒的旋转角大致相同;最后,对底火上多个击痕的图像进行处理得到其整体轮廓,并解算出该轮廓的最小外接圆半径。轮廓最小外接圆半径与单个击痕圆半径之差即为火炮击针偏心度。采用蒙特卡洛方法仿真结果表明:新方法不受药筒旋转的转角误差和击针偏心度大小的影响,测量均方差数值稳定。仿真结果验证了该方法的可行性和有效性。

Eccentricity Measurement of Firing Pin Based on Minimum Circumscribed Circle of Multiple Firing-indentations

Aimed at the problem that more than two firing-indentations will have overlapping against a single firing-indentation contour circle fitting,a method to achieve eccentricity detection of the gun firing pin by measuring the minimum circumscribed circle of multiple firing-indentations overall outline was presented. Firstly,the cartridge primer hole filling ductile metal was fired only one times,to obtain the image of the single firing-indentation,and fit out the circle radius of the firing-indentation contour. Then,the ductile metal was fired again,total no less than three times,and the cartridge rotation angle is much the same between any two firing. Finally,the image of multiple firing-indentations on primer was processed to get the whole contour,and the minimum circumscribed circle radius of the outline was calculated. The difference of fitting circle radius between the multiple firing-indentations and the single firing-indentations was used as the firing pin eccentricity. The simulation results come from Monte Carlo method show that the new method is not affected by the influence of angle error of rotation of the cartridge and the firing pin eccentricity size,the mean square deviation of measure result stability. The results show that the new method is feasible and available.