铁路车轮外形曲线数字测量仪的研究

通过对采用二连杆串联机构的便携式车轮外形数字测量仪的研究,发现该测量仪的2个零位角度安装误差将分别导致测量结果的方位和形状误差。为此,笔者提出了一种借助2种姿态测量同一段曲线,使2个结果重合,以辨识2个活动杆夹角零位误差的标定方法,试验结果证明了其有效性。以二连杆机构外形测量仪研究为基础,笔者进一步提出了基于平面五连杆并联机构的测量仪新方案,并建立了测量模型;对角度分辨率导致的测量误差的对比仿真表明,新方案有较高的精度,同时讨论了用偏置角度和增加采样率提高测量准确度的方法。

Study on the Digital Profilometer of Railway Wheels

The digital portable profilometer of railway wheels is investigated, which uses the two-bar mechanism in series with joints. It is found that two zero angle installation errors of encoders may respectively result in position and form errors of the measured object. So the method to recognize zero angle installation errors between two active bars is proposed, acquiring the data by measuring the same section of the curve with two poses and by making two results overlapping. Calibration validity is proved by experiment results. Based on the study of the two-bar profilometer, a new scheme of the profilometer using the planar five-bar parallel-connected mechanism is proposed and its mathematic model is established. Emulation comparison of measurement errors caused by angle resolutions proves that the new scheme is of better precision. The methods by offsetting angles and increasing sampling frequencies are discussed at the same time for precision improvement.