微小力值测量及溯源理论与方法研究

发布时间：2019-03-30 09:10

【摘要】：在微纳计量领域,微小力值的测试技术广泛应用于生物医药、新材料、微电子等多个领域。建立高准确度的微纳计量基标准可以保证微纳技术领域快速可持续发展。本文的研究目标是通过建立高准确度计量标准、采用适当的量值传递途径和方法,实现微纳力值的SI(International System of Units)溯源。微小力值装置可以采用电学方法复现,通过电学量、几何量的精确测量实现微小力值的传递。由于微小力值易受到环境干扰,因此本文重点研究了微小力值测量过程中抗干扰技术,并探索了基于悬臂梁刚度的力值标准传递方案,完成了理论分析和实验验证。本文的主要工作如下:1.系统分析了国内外在微纳力值计量领域的研究现状,搭建了力值测量与溯源标准装置,搭建了dC/dz测量模块、内电极平衡位置监测模块和误差校正、滤波算法。2.讨论了微小力值测量过程中抗干扰技术。分别研究了地面振动、空气扰动、电磁干扰、弹性支撑的热噪声对微纳力值的影响。采用空气阻尼方案减小了地面振动的影响,系统的阻尼比由0.0005增加至0.1,从而增大了系统的稳定裕度及抗振性能,使得位移输出的均方差由原来的1μm降低到0.1μm。电磁屏蔽减小了电磁干扰对电容值的影响。提出采用牛顿差商法来减小弹性支撑热噪声对微小力值测量的影响。3.完成了电容梯度测试,测量结果的均值为0.9269 pF/mm,方差为0.0006pF/mm,相对方差为0.067%;分析了导致电容梯度不确定的来源以及相应的解决方案。将静电力与标准质量比对,通过对实验结果进行分析,得出导致测量分散性的固定误差来源以及与质量大小相关的误差。并对实验结果进行不确定度分析,包括地面振动、空气扰动等A类不确定度和电容梯度、电压源、激光尺等引起的B类不确定度。实验结果表明,测量结果的合成误差小于2%。4.探索了基于微力标准装置的力值标准传递技术。分析原子力显微镜悬臂梁作为微力传感器在力学特性上的优势,采用标定悬臂梁刚度的方法进行力值标准传递。提出一种基于振动的快速、可靠的方法,准确地确定悬臂梁刚度。在这种方法中,悬臂梁刚度可以通过测量接触已知柔性铰链平行四边形前后的共振频率的变化来确定。5.提出了多点法测量悬臂梁刚度,并通过不确定度分析,计算出使得总体不确定度最小的测量点位置,通过改装现有的装置完成了相关实验,将悬臂梁刚度的不确定度ukc作为测量点的函数进行讨论,并通过优化多点测量点的位置选取使得ukc最小。结果表明:对于刚度为0.1 N/m的悬臂梁,测量的不确定度小于8%。
[Abstract]:In the field of micro / nano measurement, the measurement technology of micro force value is widely used in many fields such as biomedicine, new materials, microelectronics and so on. The rapid and sustainable development of micro / nano technology can be ensured by establishing a high accuracy standard for micro / nano metrology. The research goal of this paper is to realize the SI (International System of Units) tracing of micro-and nano-force by establishing high-accuracy measurement standard and adopting appropriate way and method of value transfer. The micro force value device can be reproduced by electrical method, and the transmission of micro force value can be realized by precise measurement of electrical quantity and geometric quantity. Because the small force value is easy to be disturbed by the environment, this paper focuses on the anti-interference technology in the process of measuring the micro force value, and explores the standard transfer scheme of the force value based on the stiffness of the cantilever beam, and completes the theoretical analysis and experimental verification. The main work of this paper is as follows: 1. The research status in the field of micro-nano force measurement at home and abroad is systematically analyzed. The standard equipment for force value measurement and traceability is set up, and the dC/dz measurement module, internal electrode balance position monitoring module and error correction, filtering algorithm. 2. The anti-interference technique in the process of measuring micro force is discussed. The effects of ground vibration, air disturbance, electromagnetic interference and thermal noise of elastic support on the micro-nano-force are studied. The air damping scheme is used to reduce the influence of ground vibration, and the damping ratio of the system is increased from 0.0005 to 0.1, which increases the stability margin and anti-vibration performance of the system, and reduces the mean square error of displacement output from 1 渭 m to 0.1 渭 m. Electromagnetic shielding reduces the influence of electromagnetic interference on capacitance. Newton difference quotient method is proposed to reduce the influence of thermal noise of elastic support on the measurement of micro force. 3. The capacitance gradient test is completed, the average value of the measurement results is 0.9269 pF/mm, variance is 0.0006 PF / mm, the phase difference is 0.067%, and the source of uncertainty of capacitance gradient and the corresponding solutions are analyzed. By comparing the electrostatic force with the standard quality and analyzing the experimental results, the source of the fixed error and the error related to the mass of the measurement dispersion are obtained. The uncertainty analysis of the experimental results, including ground vibration, air disturbance, class A uncertainty and class B uncertainty caused by capacitance gradient, voltage source and laser ruler, is carried out. The experimental results show that the synthetic error of the measured results is less than 2%. The transfer technology of force value standard based on micro-force standard device is explored. The advantages of atomic force microscope (AFM) cantilever beam as a micro force sensor in mechanical properties are analyzed, and the standard transfer of force value is carried out by the method of calibrating the stiffness of cantilever beam. A fast and reliable method based on vibration is proposed to determine the stiffness of cantilever beam accurately. In this method, the stiffness of cantilever beam can be determined by measuring the change of resonance frequency before and after contact with known flexure hinges parallelogram. The multi-point method is put forward to measure the stiffness of cantilever beam. Through the analysis of uncertainty, the position of the measuring point which makes the overall uncertainty minimum is calculated, and the related experiments are completed by modifying the existing device. The uncertainty of stiffness of cantilever beam ukc is discussed as the function of measurement point and the ukc is minimized by optimizing the location of multi-point measurement point. The results show that the uncertainty of measurement is less than 8% for the cantilever beam with a stiffness of 0.1 N / m.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB93

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