压电陶瓷管的微位移测量与非线性校正

Measurement and nonlinear correction for micro-displacement of piezoceramic tube

为了对原子力显微镜(AFM)中压电陶瓷管扫描位移进行非线性校正,提出了一种微位移测量与校正的简易方法。采用涡流位移传感器测量微位移,将其放大100倍以提高检测灵敏度;得到了压电陶瓷管的位移-电压曲线,其最高位移分辨率计算值为0.4 nm。根据AFM中压电陶瓷管的工作特点,确定扫描范围下测量得到的位移-电压关系,通过对等间隔像素点施加对应的非等间隔控制电压序列的方法进行非线性校正,依据像素点精度要求通过插值算法获得控制电压序列。系统采用LabVIEW虚拟仪器技术,校正后压电陶瓷管最大位移滞回偏差从10.1%降为0.4%。实验表明:扫描频率和扫描像素分辨率调节方便,同时校正算法复杂度也有所降低。

A simple way to measure and correct the micro-displacement of a piezoceramic tube used in an Atom Force Microscope（AFM） is proposed. The X/Y micro-displacement is detected by an eddy current meter and it is amplified by 100 times to improve the detection sensitivity. The relationships between the displacements of piezocaramic tube and the control voltages are obtained,and the highest resolution of displacement is calculated to be 0.4 nm. According to the working feature of the tube, the nonlinear correction is realized by applying non-equidistant control voltage sequences to scanning equidistant pixel,in which non-equidistant control voltage sequences with different pixel resolutions are obtained through interpolation based on the measured displacement-voltage relationship. The experimental results show that the maximum hysteresis error of full scale is reduced from 10. 1% to 0.4%. It is concluded that the proposed method can adjust the scan frequency and pixel resolution easily, and can reduce the complexity of correction algorithm greatly.