微悬臂梁动态特性表征用真空系统的仿真研究

Construction and simulation of a vacuum system for characterizing the resonant properties of dynamic microcantilevers

本文研究了用于表征微悬臂梁动态特性的高真空系统,研究了用于夹持微悬臂器件的样品台和用于调节真空室内压力的精密可调漏气阀。该阀在不同压力区间下采取机械机构和压电陶瓷驱动器改变阀门开度,具有精度高、适用范围广等优点,利于实验研究和工程测试。模拟分析结果表明该阀能精确调节10-6Pa^103Pa内压力。系统设置了减振支架和底座,用波纹管连接真空室和抽气系统,对系统振动信号的模拟计算表明所用减振支架和底座能够减小杂质振动信号对微悬臂梁动态特性测定的干扰。采用一般商用漏气阀控压,对微悬臂梁品质因数的测定实验结果表明了表征系统及精密阀的实用前景。

A high vacuum system was developed to characterize the resonant properties of microcantilevers. A sample holder and a precision leak valve were devised to fix the microcantilever and to adjust pressures of the vacuum chamber, respectively. Theoretical model of the pressure regulation process was built. The simulation results indicate that the valve can accurately adjust the chamber pressure from 10-6pa up to 10-1Pa through a piezoelectric ceramic spool and from 10-1pa to 10^3pa via a conventional mechanical component. To protect the cantilever from external vibrations, a bracket with multilevel damping rubber was adopted and bellows were used to connect the chamber and the vacuum pumps. Their efficacy is revealed in the virtual calculation of the vibration strength. The practical application prospect of the valve is demonstrated by measuring the dependence of a microcantilever quality factor on the pressure as detected in a homemade vacuum system with a commercial precision leak valve.