Research On Measurement And Standard Transfer Of Micro-nano Force Based On Electrostatic Field

Accurate metering of micro-nano force is urgently needed in the field of new materials, new technologies. Meanwhile, the calibration of various sensors for micro-nano force measurement is still lagging because of there is no uniform standard for micro force measuring and tracing around the world. The project aimed to establish a standard apparatus to provide a traceability link to the SI for force measurement and testing instruments in the range of 10-4~10-8N. In this paper, the principle of force measurement with electrostatic field and transfer of force standard is explored and verified with the construction of experimental platform. The main work can be summarized as follows:1. Analyzed the development of micro-nano force measurement at home and abroad systematically. Determined the research content and direction in view of the current faultiness.2. The principle of electrostatic force generation with cylindrical capacitive sensor was studied. Analyzed and calculated the capacitance gradient of the sensor with offset and tilt based on the theoretical model. Proposed a reasonable method to measure the electrode offset and capacitance gradient with high-precision image sensors and machine vision algorithms.3. According to the system requirement, proposed the differential parallelogram flexible hinge mechanism to be used as elastic element to transfer force.Analyzed the static and dynamic stiffness with the mathematical model. Besides, made some optimization design for the flexible hinge.4. Completed the construction of the system and introduce the function of main module. Did the selection and Implementation of hardware and algorithm optimization and man-machine interface development in software.5. Uncertainty analysis for the micro-nano force measurement system, which include the type A uncertainty source such as the ground vibration and air turbulence and type B uncertainty caused by capacitance gradient, voltage source, laser ruler etc.. The relative uncertainty is 2.5% in the measurement of micro-nano force about 20?N, better than expected target of 5%.6. Researched the force standard transfer technology based on the micro-nano force measuring system. Considering the advantage of atomic force microscope cantilever in the mechanical properties, determined to transfer force standard through calibrating the cantilever spring constant. Test with three types of AFM cantilever showed that the repeatability error is less than 0.2N/m and the method is feasible.