Design and Sensing Theory for Flexible Multi-Layer Equal Strength Beam Force/Displacement Sensors With High Sensitivity
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摘要:
针对目前柔性传感器大多数结构为薄膜形式,不利于法向集中力与位移同时测量的问题,设计并制备了一种基于多层离子皮肤(柔性电容传感片)的等强度梁式传感器. 该触觉传感器由多层离子皮肤和等强度梁构成. 当梁的自由端接触被测物时,传感器可以将力或位移转化为输出的电容信号来进行法向接触力或位移的测量. 建立了传感器电容变化量与梁自由端力/位移关系的传感理论模型,并通过力/位移加载试验对传感理论模型进行验证. 试验结果表明,传感器的传感理论模型与试验结果吻合较好,当传感器具有四层结构时,对力/位移测量的灵敏度分别为1.855 mN/pF和0.694 mm/pF. 所能测得最小力为0.02 mN,最小位移为0.01 mm,同时该传感器表现出良好线性度(R2=0.994). 该传感理论模型可为此类传感器的设计提供理论依据,在柔性机器和医疗健康检测等领域具有良好的应用前景.
Abstract:An equal-strength cantilever beam sensor based on the multi-layer ionic skin (flexible capacitance sensor chips) was designed and prepared, to solve the problem that most existing thin-film-structure flexible sensors cannot simultaneously measure concentrated normal forces and displacements. The proposed sensor is comprised of the multi-layer ionic skin and the equal-strength cantilever beam. The normal contact forces or displacements can be acquired through measurement of the capacitance change of the sensor, with the free end of the beam contacting the measured object. A theoretical sensing model of the relationship between capacitance change and force/displacement was established and then verified through displacement/force loading tests. The test results show that, the sensing model is in good agreement with the test data. For the measurement of force and displacement, the sensitivity of the sensor with a 4-layer structure is 1.855 mN/pF and 0.694 mm/pF, respectively. The minimum measurable force is 0.02 mN and the minimum measurable displacement is 0.01 mm. At the same time, the sensor shows good linearity (R2=0.994). This sensing model provides a theoretical basis for the design of such sensors with good application prospects in the fields of flexible machines and medical health detection.
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Key words:
- flexible sensor /
- equal strength cantilever beam /
- displacement /
- force
edited-byedited-by1) (我刊编委刘少宝推荐) -
表 1 不同传感器可测量的最小力对比
Table 1. Minimum detectable forces with different sensor types
source type minimum detectable force ref. [27] capacitance sensor 0.07 N ref. [28] capacitance sensor 0.01 N ref. [29] capacitance sensor 0.009 N ref. [30] capacitance sensor 0.05 mN ref. [20] fiber Bragg grating sensor 0.011 N ref. [31] piezoresistive sensor 0.08 N ref. [32] piezoelectric sensor 0.05 N ref. [33] optical sensor 0.52 mN this work capacitance sensor 0.02 mN 表 2 不同传感器所探测到的最小位移对比
Table 2. Minimum detectable displacements with different sensor types
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