给出了一种高效实用的超声自动检测路径校验方法：将探头在声束方向上延长合适的距离得到一个虚拟的圆柱体,路径校验转化为构件表面与虚拟圆柱体的干涉检测。在干涉检测中首先将构件曲面分解成若干曲面片并利用包围盒表示,然后采用投影法将圆柱体和包围盒的空间干涉问题转化为平面干涉问题,只需计算投影图是否有重叠就可判断是否干涉,如果存在干涉便将包围盒中的曲面片进行细分并用若干四边形表示,继续采用投影法进行精确检测。最后通过实验验证了该方法的有效性,并讨论了包围盒的选取对算法性能的影响。
An efficient and practical methodology was proposed to realize the path checking: a virtual cylinder was obtained when the transducer was prolonged in the direction of ultrasonic beam, then the path checking was replaced by interference detection between the virtual cylinder and the surface of component. In the interference detection, firstly the surface of component was discretized into many patches presented by bounding box. Secondly the algorithm of orthographic projections was used to detect the collision between the virtual cylinder and bounding box. After that, the patches of the component which interfere with bounding box were subdivided into many quadrangles, finally interference detection between cylinder and quadrangles was conducted so that the accurate results of path checking can be obtained. The influence on algorithm’s performance of choosing bounding boxes was discussed. The results of many experiments show the validity of this method.
