Design And Implementation Of High-precision Digital Displacement Measuring Device Based On Grating Sensor

In the fields of machining manufacturing,precision instruments and equipment,aerospace engineering and other fields,the demand for displacement measurement accuracy is becoming higher and higher,and the traditional measurement methods can no longer meet the demand.Grating displacement measurement technology has advantages such as high accuracy,high sensitivity,fast measurement,and large travel.However,high-precision grating sensors are very expensive,and it is difficult for grating measurement systems to simultaneously meet the requirements of high resolution,high accuracy,and high reliability.Therefore,this article designs a low-cost and high-precision grating digital displacement measurement device,and the main research content is as follows:(1)We have determined the combination of sine and cosine of grating signals and amplitude segmentation method,and divided the high-power measurement device into two parts: coarse and fine segmentation and fine segmentation.In terms of coarse and fine segmentation,the entire cycle is divided into 8 intervals,and the absolute value and polarity of each interval are determined to achieve eight times coarse segmentation;In terms of fine segmentation,the method of constructing positive and cotangent functions is used to improve the linearity of the signal,and then the amplitude segmentation method is used to achieve 256 times fine segmentation;(2)In MATLAB,the stability,amplitude uniformity,orthogonality and sine of the grating signal are analyzed by mathematical simulation,so as to calculate the corresponding relationship between the amplitude sampling subdivision multiple and the technical indicators,which lays the foundation for the subsequent design and physical building.(3)Completed the software and hardware design of the grating displacement device.Based on the characteristics of the grating displacement measurement system,the analysis results of grating signal error,and the determination of high magnification subdivision algorithm,a design scheme for a high-precision grating digital displacement measurement device is proposed,which is mainly divided into hardware and software design parts;The hardware design includes three modules: grating preprocessing circuit module,function signal construction circuit module,and FPGA+ARM control circuit design.Experimental debugging was conducted on each module of the hardware,and the processed signal waveforms of each part were provided;The software design includes two modules: FPGA software design and MCU software design,and each module of the software has been simulated and debugged.(4)A grating displacement measurement device with a stroke of 0-25 mm has been built.Comparative experiments were conducted on this device using the XL-80 Renishao laser interferometer,and three sets of forward and reverse data were measured.The grating displacement measurement device was analyzed for indicators such as resolution,linearity,and measurement accuracy;The total subdivision factor of this device is 2048 times,and the measurement resolution is 20 μ Increase m to 0.01 μm.The measurement error is ± 0.98 μm.This article provides a detailed plan for the software and hardware design of a grating displacement measurement device,builds a physical device,and conducts relevant comparative experiments.The experiment proves that the designed grating displacement measurement device has certain application value and promotion significance.Future research can further optimize hardware and software design to achieve higher accuracy and wider applications.