Research On Grating Signal Subdivision Algorithm And Grid Distance Measurement Error

The rapid development of electronics and computer technology has promoted the development of the manufacturing industry.As the vanguard of the development of the manufacturing industry,precision measurement must inevitably take the lead in promoting precision,intelligence,and integration in the manufacturing industry.Grating sensors are widely used in mechanical precision measurement due to their non-contact nature,high measurement accuracy,and strong anti-interference ability.China lags behind foreign countries in research on grating displacement sensors.At present,low precision grating displacement sensors in China meet the domestic market demand,but high-precision grating displacement sensors still cannot meet the domestic market demand.Comprehensive research on the current status of subdivision methods and signal compensation methods for the output Moir é fringe signal of grating sensors both domestically and internationally.This article applies research on the compensation and software subdivision methods of Moire fringe signals.Firstly,a new software subdivision method is proposed based on the arcwise subdivision method and the triangular wave subdivision method.Based on the characteristics of the waveform generated by using the subdivision method for Moir é fringe signals,this paper names it the quadratic triangular wave subdivision method.Compared with the arctangent subdivision method and the triangular wave subdivision method,the quadratic triangular wave subdivision method has a linearity of 95.78%,which is 4.8% higher than the arctangent subdivision method;The frequency is twice that of the arcwise subdivision method and the triangular wave subdivision method.This method divides the coarse and fine grid spacing by 16 times,and in conjunction with the analog-to-digital acquisition module ADC for fine segmentation,the combination of the two can achieve high magnification subdivision.Secondly,the signal compensation scheme is studied based on the quadratic triangular wave subdivision method.A study was conducted on the control variables of DC voltage error,amplitude inequality error,and non orthogonal phase error that affect the subdivision error of two Moire fringe signals.The maximum voltage error values of the above three types of errors after the quadratic triangular wave subdivision method were obtained through MATLAB simulation.Based on the simulation data,linear fitting was performed to obtain the linear relationship between the three types of errors and the maximum voltage error value of the ideal quadratic triangular wave subdivision method,Provide the technical indicators that should be achieved for each error after signal compensation.A scheme is proposed based on peak detection method and coordinate rotation method(CORDIC)algorithm to sequentially compensate for DC voltage error,amplitude inequality error,and non orthogonal phase error.Once again,write an FPGA program,and based on FPGA,write a software subdivision algorithm program for grating pitch subdivision 1024 times.Simulate its digital filtering(FIR),shaping,counting,and direction discrimination modules to verify the feasibility of the signal compensation scheme and the quadratic triangular wave subdivision method proposed in this paper.Finally,an experimental platform was established to validate the proposed quadratic triangular wave subdivision method and compensation method in this paper.The experimental data was obtained through the upper computer and processed and analyzed.Under the condition of meeting the signal frequency requirements,achieve 1024 times subdivision of the subdivision system,with a subdivision error of less than 1.17%.Verify the feasibility of the software subdivision method and signal quality compensation method proposed in this article.