基于PVDF的三维纳米谐振触发测头及定位系统

微纳米三坐标测量机(Coordinate measuring machining,CMM)是目前微纳米三维测量领域的一个研究热点,针对微纳米CMM中三维纳米测头的研究瓶颈,提出一种与现有机械接触式测头和光学非接触式测头工作原理完全不同的、可达到纳米/亚纳米量级触发分辨力的新型谐振测头。利用聚偏氟乙烯(Poly vinylidene fluoride,PVDF)薄膜的压电特性和其谐振参数对微小作用力的高敏感性,PVDF薄膜与一体式光纤微测杆测球相结合构建成了基于PVDF薄膜的三维纳米谐振触发测头。该测头在z向以轻敲模式接触,在x、y向以摩擦模式接触。经过试验验证,由该测头与三维纳米定位平台、数据处理及反馈控制系统相结合构建成的三维谐振纳米触发定位系统在x、y、z三个方向的触发分辨力都达到了亚纳米量级,分别为0.12 nm、0.10 nm、0.12 nm;三维重复性误差分别为26 nm、36 nm、10 nm。试验结果证实了新型三维谐振测头及其系统的有效性。

石英音叉三维谐振触发定位系统

为实现对微器件等三维测量时在三维方向上任意单点的高精度触发定位,提出一种新型三维谐振触发定位系统。以石英音叉作为微力传感器,与一体式光纤微测杆测球相结合,利用其谐振参数(谐振振幅、谐振频率/谐振相位)对微力的高敏感性构建三维谐振触发测头。将该测头与三维纳米定位台、反馈控制模块、信号处理电路结合,分别构成完整的振幅反馈和相位反馈三维谐振触发定位系统。工作时驱动石英音叉测头处于谐振状态,检测顶端测球与试样表面接触微力引起的振幅变化或频率变化。测头顶端测球与试样表面在Z向以轻敲模式接触,在X、Y向以摩擦模式接触。实验结果显示:系统在X、Y、Z 3个方向的触发分辨力分别达到0.17 nm、0.20 nm、0.18 nm;三维重复性误差分别达到37.0 nm、70.6 nm、41.0 nm。实验结果验证了提出的三维谐振触发定位系统纳米量级精确定位的可行性和有效性。

基于石英音叉谐振测头的喷油嘴微锥孔测量

柴油发动机喷油嘴喷油孔具有孔径小和深宽比高等特征,其几何参数对于保证燃油雾化质量、发动机燃烧效率以及降低污染物排放极其重要。基于石英音叉光纤一体式三维谐振测头,提出了喷油嘴微锥孔测量方法。通过测头在谐振状态下受到微力后谐振参数的改变来实现高精度触发定位,从而对具有设计指标的喷油嘴微锥孔进行测量,得出微锥孔的锥角参数。试验结果验证了该测头在微小元器件精密测量方面的有效性。

Magnetic field strength and temperature-dependent calibration system of Hall probe for the HEPS-TF cryogenic permanent magnet undulator

Purpose High energy photon source test facility(HEPS-TF)has manufactured a three-dimensional Hall probe to measure the cryogenic permanent magnet undulator(CPMU).Since the operating environment of the CPMU is the subcooled liquid nitrogen(85K),the temperature of the Hall probe will have a decrease of several degrees while carrying out the local magnetic measurement.We established a magnetic field strength and temperature-dependent calibration system to calibrate the Hall probe.Methods The magnetic field strength of the Hall probe was calibrated by a standard dipole electromagnet and a nuclear magnetic resonance Tesla meter(NMR).The temperature of Hall probe was controlled by a control system which can modulate temperature from 0℃ to 30℃.Results A new homemade Hall probe has finished the temperature-dependent(0℃ to 30℃),magnetic field strength(-1.2 to 1.2 T)and angle error calibration at this new calibration system.The temperature correction error is less than 0.045%.The calibration error of magnetic field strength is less than 1.5 Gs.The RMS calibration error of Hall sensors angle matrix is less than 5.1E-5.Conclusion The magnetic field strength and temperature-dependent calibration system including a standard dipole electromagnet,a temperature regulation system,an NMR and a five-dimensional Hall bench was established.The detailed magnetic field strength and temperature-dependent calibration system is introduced and the results of the calibrations are presented.