融合激光外差和线性调频技术, 基于磁致伸缩系数测量原理, 将磁致伸缩系数的测量转换成微小长度变化量的精确测量, 并提出一种线性调频多光束激光外差复合检测磁致伸缩系数的新方法, 即通过线性调频技术将待测微小长度变化量信息加载到多光束激光外差信号的频率差中, 经外差信号解调后可以同时得到多个微小长度变化量值, 对这些数值加权平均, 可以精确获得微小长度变化量数值, 最终进一步提高磁致伸缩系数测量精度。利用该方法, 仿真研究了不同电流条件下, 待测样品的磁致伸缩系数, 结果表明: 相对测量误差小于0.09%, 与传统测量方法相比, 测量精度提高了一个数量级以上。

Combining laser heterodyne with linear frequency modulated technology, based on the measurement method of magnetostrictive coefficient, a novel method of linear frequency modulated multi-beam laser heterodyne measurement for magnetostrictive coefficient was proposed, which converted the measurement of magnetostrictive coefficient into the length variation. Based on linear frequency modulated technology, the information of length variation was loaded into the frequency difference of the multi-beam laser heterodyne signal, and many value of length variation could be acquired simultaneously after the multi-beam laser heterodyne signal was demodulated. Processing these values by weighted-average, length variation could be obtained accurately, and eventually the accuracy of magnetostrictive coefficient was improved. The magnetostrictive coefficient of the sample under different currents was simulated by Matlab. The results indicate that compared with traditional technique, the relative measurement error of this method is less than 0.09% and the accuracy is improved more than one order of magnitude.