基于位置传感器(PSD)的特性,提出了一种长距离曲线型微细管道内表面形貌无损检测技术,开发了相应的管道内表面形貌检测器.激光束经过2次反射后,在管道内壁上形成细小的光斑.该光斑被二维PSD接收,产生4路电流信号.根据这些信号和检测器的结构参数,可以计算出对应光斑在局部三维坐标中的位置.反射镜在微型马达带动下旋转1周,使激光束完成1个管道截面环的扫描,从而得到该截面上所有采样点的相对坐标.最后对测量数据进行分割、拟合等处理,重构出截面环的形状,得到该截面处的管道半径以及缺陷情况.在微型管道机器人的带动下,可以对整条管道进行检测和三维重构.根据该技术开发的检测系统,可以实现内径在9.5～10.5 mm、曲率半径大于100 mm的曲线型长距离微细管道内表面的检测,对管道内壁缺陷的测量精度达到±0.1 mm.
The presented system consists of field devices, a control system and a host computer system. The field devices, which are composed of an in-pipe micro-robot, a displacement sensor, a curvature sensor, and an inner surface measurement unit, can go into the pipe to get the data of displace- ment and axis curvature, and the shape data of the inner surface. With the conic-shape laser beam shot by the inner surface measurement unit, the intersectional curve between the laser beam and the inner-surface of the tested pipe can be calculated in the local coordination system （LCS） of the inner surface measurement unit. The relation between the LCS and the global coordination system （GCS） can be deduced, too. After the robot reaches the end of the pipe, all measured intersectional curves can be translated into the same coordination system to become a point cloud of the inner surface of the pipe according to the relations between LCS and GCS. Depending on this points cloud, the CAD model of the inner surface of the pipe can be reconstructed easily with reverse engineering tools, and the feature of flaw of the pipe can be obtained with flaw analysis tools.
Li Jiangxiong Ke Yinglin Guo Tong Wu Enqi Jin Chengzhu
