The Research Of Compensation Technique For Data Age Error In Dynamic Angle Measurement By Rotary Grating

In geometric measurement,angle measurement has always been one of its important branches.As the most commonly used precision sensor in angle measurement,rotary grating has already had a very high measurement level in the field of static angle measurement,but it is underqualified for dynamic angle measurement in real-time measurement.It can not take into account the two requirements of angle measurement accuracy and measurement speed.The inaccuracy of measurement time introduces large error and reduces dynamic angle measurement accuracy for dynamic angle measurement results.Therefore,eliminating this error and using it as an important technical means to improve the dynamic angle measurement accuracy of the rotary grating has important research value.This paper studies the development status of dynamic angle measurement technology at home and abroad,studies the compensation method of dynamic angle measurement error,proposes the concept of data age error,establishes the quantitative model of data age error based on algebraic derivative estimation method,and studies the dynamic angle measurement error compensation technology of rotary grating.The following is a brief summary of the content of this paper:(1)According to the phenomenon that the output angle of the rotary grating dynamic angle measurement is not real-time,resulting in low measurement accuracy,so as to analyze the correspondence between the time and the measurement error,clarify the definition of the data age error;the data age error is classified into the time-delay error and phase-shift error according to different sources.Select the appropriate quantization method for different types of data age error sources;propose the compensation model of data age error,and elaborate the compensation process.(2)Aiming at the defect that the traditional finite difference method amplify high frequency noise while calculating the angular rate and angular acceleration rate while,introduced the algebraic derivative estimation method,which will obtain stable and reliable grating motion state information with low-pass filtering characteristics.Aiming at the two major imperfections of the fitting error in the derivation model of the algebraic derivative estimation method and the existence of the zero point in the denominator of the formula,a solution for periodic initialization and dual-thread synthesis is proposed.(3)The value of Taylor's fitting polynomial expansion order is discussed,and the appropriate order is measured between the fitting precision and the on-chip resources when the time-delay error quantization model based on Taylor formula and the algebraic derivative estimation model based on Taylor formula are proposed.(4)In view of the high real-time requirements of dynamic angle measurement,the FPGA-based hardware circuit platform is built as the grating Moiré signal processing system;aiming at the problem that the actual working effect of the FPGA circuit cannot be verified on the pure simulation platform,the hardware-in-the-loop simulation of the data age error compensation accuracy verification platform to verify the effectiveness of the data age error compensation technique is established.