The modeling and experiments of a PVDF mirco-force sensor

This paper aims at designing a kind of advanced micro-force sensor that can measure force in the range of sub- micro-Newton (muN). To accurately measure the micro interactive force (for example, adhesion, surface tension, friction, and assembly force) acting on micro devices during micromanipulation, the polyvinylidene fluoride (PVDF) is fabricated highly sensitive force sensors. This paper illustrates the modeling method of a PVDF sensor. The transformation between the micro interactive force and the output of the sensor is described. To calibrate the transformation, the model of the PVDF cantilever beam that shows the relationship between the interactive force and the deflection of the sensor probe tip is built first. Then, by given deflection, the interactive force can be calculated with the model. Finally, the transformation can be calibrated. Experiment results verify the effectiveness and accuracy of the transformation model, and the sub-muN sensitivity of the sensor. This micro force sensing technology will solve an important problem that restricts the development of micromanipulation and batch assembly of micro devices.