基于随机共振增强的仿生纤毛微剪应力传感器研究

High sensitivity, high reliability, and vector detection capability is the development trend of the MEMS shear stress sensor. Inspired by the creature’s perception mechanism of hair cell, we propose the MEMS bionic vector shear stress hair sensor with stochastic resonance in this project. Firstly, by using the fluid-solid-electrostatic coupled analysis, we will discover the interaction mechanism among the fluid, hair, flexible membrane and capacitance, and subsequently deduce the change rules of shear stress-hair motion-capacitance change. The nonlinear system with a bistable potential well is realized by using periodic finger capacitive structures and gap change capacitive structures，thereafter we try to study the mechanism of controllable stochastic resonance about the weak shear stress under the effect of the noise and the nonlinear system. Based on UV-LIGA and DRIE, three dimensional heterogeneous process is designed, which is used to fabricate the bionic hair micro sensor. Then, combining the stochastic resonance drive circuits with dynamic measurement of the sensor in air or water, the proper drive voltage of realizing stochastic resonance will be obtained, together with its enhanced effect. Finally, the test of bionic hair MEMS shear stress sensor will be proceeded. The research achievement of this project may establish important foundation for realizing precise measurement of shear stress and active flow control and offer new method of detection of subthreshold signals, thus, has important scientific and practical significance.

实现高灵敏度、高可靠性的矢量测试是微剪应力传感器的发展方向。本项目模仿生物纤毛感知系统的结构和机理，提出一种新型的基于随机共振工作原理的仿生纤毛矢量微剪应力传感器。首先，建立流体-固体-静电的耦合分析模型，揭示流体、纤毛、柔性膜、电容之间相互作用机理，获得剪应力-纤毛运动-电容变化的基本规律；构建基于梳齿电容和变间隙轴向电容的双稳态势阱非线性系统，并完成微弱剪应力信号输入经该非线性系统、输入噪声作用的随机共振可控实现机理研究；基于紫外深刻电铸模造和深反应离子刻蚀组合工艺的三维异质微加工集成制造方法，实现仿生纤毛微传感器的加工；再通过随机共振测控电路，并结合传感器的动态响应测试，探索确定随机共振实现的控制电压参数及随机共振增强效应；最后进行实验测试研究。本项目的研究成果将为剪应力精细化测试和主动流动控制的发展奠定研究基础，为亚阈值传感信号提取提供新思路，具有重要的科学意义和工程实用价值。

实现高灵敏度、高可靠性的矢量测试是微剪应力传感器的发展方向。本项目模仿生物纤毛感知系统的结构和机理，提出了仿生纤毛矢量微剪应力传感器。首先运用解析法和有限元软件相结合的方法，对仿生纤毛微传感器进行了流体-固体-静电仿真分析，获得了剪应力（流速）-纤毛运动-检测电容变化的基本规律，完成了仿生纤毛微传感器感知机理分析。然后，根据微纤毛传感器技术指标要求和微加工工艺能力，完成了柔性膜仿生纤毛微传感器和折叠梁仿生纤毛微传感器的整体结构方案和结构参数的设计。根据随机共振所需双稳态势能构建需求，得到了相应梳齿排布、尺寸和激励电压的参数。结合整体结构设计方案，开发了基于紫外深刻电铸模造和深反应离子刻蚀组合工艺的三维异质微加工工艺流程，完成了包含全工艺流程的掩模版的设计和制备。使用制备的全工艺流程掩模版，开展了仿生纤毛微传感器的工艺研究，完成包含pyrex刻蚀和底部电极的下定子加工工艺，SOI硅基片上的中间层一次DRIE刻硅、RIE刻二氧化硅、类Through Silicon Vias（TSV）结构的跨硅和二氧化硅的盲孔镀铜以及二次DRIE刻蚀组合工艺流程，pyrex下定子和SOI硅片键合，DRIE刻蚀上定子制备了硅轴向电极、硅连接柱及氧化硅刻蚀孔，基于ADEX干膜的柔性膜和基于SU-8光刻胶的纤毛制备。制备了线运动折叠梁仿生纤毛传感器表头。研制了基于电容检测集成芯片、STM32芯片、无线模块的传感器无线开环测控电路系统。研制了可实现闭环检测和控制的传感器测控电路系统。确定了随机共振实现的控制电压参数及随机共振增强效应。基于电路系统，进行了仿生纤毛微传感器测试。本项目可为流场精细化测试提供新的技术手段，并为主动流动控制技术的发展提供重要的研究基础。