磁场式位移传感器误差的数理模型研究

Research on mathematical and physical model of magnetic displacement sensor error

现场自校准技术关系到磁场式位移传感器的生命。由于两个传感器在加工、安装上细微的不一致,导致现有的"多传感器协同修正"的误差自修正方法实效并不明显。通过考察在相同的测量值微小增量情形下,其对应的间距均匀的理想转子和间距不均匀的实际转子不同的微元增量,进而在微单元层面建立起他们的数量映射关系,最终在数量上推导出整周的大范围误差的数学结构;同时,提出了一种可以在复杂工况下,不依赖于外部参考基准,从其自身的整周递增测量值序列中提取出动态误差的方法。此方法及其结论还为各类位移传感器克服刻线偏差提供了一种全新的思路和解决方案。结合实验进行验证,在一般回转精度转台下,单个位移传感器的修正精度达到峰-峰值±5.5″。

On-site self-calibration technique relates to the lifetime of the magnetic displacement sensor.Due to the slight inconsistency of the sensors in machining and installation,the existing error self-correction method based on multiple sensor cooperative correction method can not achieve obvious effect.Through observing different infinitesimal increments corresponding to the idea rotor with uniform pitch and the actual rotor with non-uniform pitch under the condition of the same tiny measurement increment,the quantitative mapping relationship of the increments in infinitesimal level is established.Finally,the mathematical structure for whole circle large scale error is derived quantitatively;meanwhile,a method extracting dynamic error from its whole cycle increment measurement value sequence is proposed under complex condition and independent of external reference standard,and a method for drawing error curve from the measurement value sequence is also given.Moreover,this method and its conclusion also provides a novel ideal and scheme for various kinds of displacement sensors to eliminate groove-width error.Experiments were conducted to verify the proposed method;on general precision rotary table,the correction precision for single displacement sensor reaches the peak-to-peak value of ± 5.5″.