摘要
为补偿激光外差干涉位移测量中因激光频率混叠引入的一阶非线性误差,提出了一种基于微分运算的非线性误差补偿算法。首先对外差干涉信号进行正交下混频,得到一对包含待测相位信息的正交信号;然后对正交信号进行微分运算,以消除频率混叠引入的直流偏移误差;最后通过反正切运算求得待测相位。设计了基于现场可编程门阵列(field programmable gate array,FPGA)的全硬件补偿算法,开展了模拟干涉信号和激光外差干涉位移测量实验。实验结果表明:采用该补偿算法后,位移测量结果的信纳比从38.59dB提高至54.65dB,各阶谐波失真减小约一个数量级,验证了所提算法的可行性和有效性。该算法可减小激光外差干涉位移测量中的非线性误差,提高测量精度。
In order to compensate for the first-order nonlinear error caused by laser frequency mixing in laser heterodyne interference displacement measurement,a nonlinear error compensation algorithm based on differential operation was proposed.First,the heterodyne interference signal was subjected to quadrature down-mixing to obtain a pair of quadrature signals containing the phase information to be measured.Subsequently,the differential operation was performed to eliminate the DC offset caused by laser frequency mixing in the quadrature signal.Finally,the phase to be measured was obtained through the arctangent operation.The all-hardware compensation algorithm based on field programmable gate array(FPGA)that can perform full hardware calculation was designed,the experiments for simulated interference signal and the measurement of the laser heterodyne interference displacement were carried out.The experimental results have shown that by using the compensation algorithm,the signal to noise and distortion of the displacement measurement results was improved from 38.59dB to 54.65dB,and the harmonic distortion of each order was reduced by about an order of magnitude,verifying the feasibility and effectiveness of the proposed algorithm.The algorithm can reduce the nonlinear error in the laser heterodyne interference displacement measurement and improve the measurement accuracy.
作者
陈洪强
谢建东
严利平
CHEN Hongqiang;XIE Jiandong;YAN Liping(Precision Measurement Laboratory,Zhejiang Sci-Tech University,Hangzhou 310018,China)
出处
《浙江理工大学学报（自然科学版）》
2022年第5期783-790,共8页
Journal of Zhejiang Sci-Tech University(Natural Sciences)
基金
国家自然科学基金项目(51875530)。
关键词
激光外差干涉
非线性误差补偿
频率混叠
微分运算
位移测量
laser heterodyne interference
nonlinear error compensation
frequency mixing
differential operation
displacement measurement
