设计了一种基于平晶扫描的轴类零件直径测量系统.激光透射旋转的平晶产生扫描平行光,扫描光偏移光轴的距离是入射角及平晶自身参数的非线性函数,光电检测及计时电路获得测量周期和对应被测工件边缘的信号跳变时间,根据时间与转动角度的比例关系将所得时间量换算成入射角度,最终实现直径测量.利用刀口法进行标定实验,分别采用参数拟合法和RBF神经网络法确定实际非线性测量方程,完成了各测头的标定,进一步实现多测头系统标定,在100 mm的测量范围内,3σ重复性误差为0.006 mm,测量误差为±0.010 mm.%A system used for diameter measurement of shaft parts based on flat-crystal scanning is designed. The parallel scanning beam is generated by laser transmission through rotary flat-crystal. The offset betweeen scanning beam and optical axis is a non-linear function of the incident angle and parameters of the flat-crystal. The time of signal jumping which is corresponding to the edge of the workpiece can be obtained by the photoelectric detection ciucuit and the timing circuit. The diameter is determined by the incident angles calculated according to the scale relation between the time and the rotation angle. Using the knife-edge method, the actual non-linear measuring equation of each sensor is aquired by means of parameter fitting and RBF neural network training and then the multi-sensor syetem is calibrated. Within the mearuement range of 100 mm,the 3σ repeatability error is 0.006 mm and the measurement error is ±0.010 mm.
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