为了摆脱对高精度基准器具的依赖实现对嵌入式角位移传感器的现场标定,结合传感器的结构特点提出了一种利用单个读数头测量值差商的方法实现自我标定.该方法利用傅里叶逼近模型将读数头的误差分离为多次谐波的叠加,采用测量值向前差商的方法获取标定模型的中间变量,运用泰勒展开对差商方法进行了误差估计,并通过提高差商阶数降低模型误差,为了保证标定精度,结合最小二乘算法对标定参数进行了寻优.运用自标定方法对两台不同对极数的嵌入式角位移传感器进行了标定实验,并与传感器常用的比较标定方法进行了对比实验.实验结果表明,两台传感器的误差分别从标定前的±30″和±25″,降低至±2.6″和±2.2″,精度得到了大幅度提高,最终的标定参数与传感器实际的误差成分相吻合,标定精度与比较标定的精度基本相同,能够满足嵌入式角位移传感器的高精度、高效率标定要求.%In order to get rid of the dependence on high precision reference and realize field calibration of an embedded type angle displacement sensor, a self-calibration method was proposed using difference quotients of measured values obtained with a discrete probe.With the proposed method, the error function of the probe was separated into multiple harmonics with Fourier approaching model.The forward difference quotient of measured values was used to get intermediate variable of the calibration model.Taylor expansion was applied to estimate errors of difference quotients, the calibration model errors were reduced through increasing the order of difference quotient.To ensure the calibration precision, the least squares algorithm was used to optimize calibration parameters.Two embedded type angle displacement sensors with different pairs of poles were calibrated using the proposed method.The results were compared with those using the traditional comparative calibration method.The actual calibration tests showed that the errors of the two sensors are reduced from ±30″ and ±25″, respectively to ±2.6″ and ±2.2″, respectively;the final calibration parameters are consistent with the actual sensors' error components;the self-calibration precision is almost the same as the accuracy of the comparative calibration, the former can meet embedded type angle displacement sensors' calibration requirements.
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