中文摘要：

为增大检测信号的输出幅值和降低反射波对测量精度的影响,在传统磁致伸缩位移传感器结构基础上,提出一种基于无阻尼扭转波干涉的位移测量方法.制作了Fe-Ga磁致伸缩位移传感器样机,检测线圈输出的电压幅值由42 mV提高到65 mV,信噪比由11.6 dB提高到22.5 dB,位移分辨力提高1倍.对扭转波的两种时间定位方法进行分析,提出了一种动态双侧阈值法的时间定位方法,给出了此方法使用的范围及阈值选取的方法,推导了此方法所能提高的测量精度,并通过实验证明了此方法的测量精度约提高了1倍.

英文摘要：

To increase the output amplitude of detecting signal and to reduce the influence of reflection wave on measurement accuracy, a displacement measurement method based on undamped torsional wave interference is proposed. The Fe-Ga magnetostrictive displacement sensor （MDS） is manufactured. The output voltage amplitude of the detecting coil is increased from 42 mV to 65 mV, the signal to noise ratio （SNR） is improved from 11. 6 dB to 22. 5 dB, and the displacement resolution is enhanced by 1 time. Based on the analysis of two time positioning methods for torsional wave, a time positioning method of dy-namic double bilateral threshold is proposed. The using range and selecting threshold of this method are given. The measurement accuracy the proposed method improves is derived. Experimental results show that the measurement accuracy of this method is doubled.