接触式弯管测量机研究

A Study on the Bent Tube Measuring Machine with a Contact V-Shaped Groove Probe

论述厂接触式弯管测量机的测量原理，并给出其具体方案．通过移动末端装有V型测量叉的铰接五轴测量臂，使V型测量叉与弯管外表面接触，完成弯管的接触测量；利用增量式光电角位移编码器的输出角和测量机各连杆的长度来计算弯管轴线的方位；基于坐标转换原理推导了测量机的数学模型．采用最小二乘法拟合弯管的轴线，减少了测量误差．测量机仅需一次与弯管外表面接触即可确定弯管某直管段的轴线．研究工作有助于国内弯管测量机的研究与开发．

The measuring principle of the bent tube measuring machine is described. The constructional design scheme of the machine is given. The measurement is accomplished by the V-shaped measuring probes fitted to the free end of an articulated five axis arm. The probe can be moved by the armto a number of positions to make contact with the bent tube for the measurements. The directional angles of the centerline of the straight portions of the bent tube are then calculated with the output angles read from an incremental photo-electric displacement encoder and the lengths of various links ofthe machine. Based on the principle of coordinate transformation, a mathematical model for the machine is developed. By the least square method, the best fitting line of the centerline of the bent tubeis determined in order to reduce the measuring errors. Only one contact between the V-shaped probeand the bent tube is needed to determine the centerline.