多电极含金属芯压电纤维仿生气流传感特性研究

Most orthopteroid insects, for crickets, have air flow sensitive hairs at the rear of their abdomen. These mechanoreceptor hairs have proven to be extremely air flow sensitive, and enable crickets to detect complex pattens produced by, for instance, predators. Each hair is attached to a sensory neuron at its base center, which is mechanically induced by stress due to hair deflection. The disturbance in the surrounding air induces vibration in the air receptor hairs, which generates impulse signals in the nerves connected to the brain of insect. Then the velocites and angular of the air flow can be detected, which enabling insect to identify and escape from predators..In this study, multi-electrodes were spurted on the surface of metal core piezoelectric fiber, called multi electrodes metal core piezoelectric fiber (MMPF). An MMPF can be used as biomimetic air flow sensor, to detect the characteration of air flow. At first, the static and dynamic constitutive equations of the cantilever MMPF in matrix forms were established. Based on the constitutive equations, the models for measuring piezoelectric parameters were proposed, and testing methods for measuring the piezoelectric parameters were designed. Then piezoelectric parameters of some MMPF were measured experimentally, to express the characteration of MMPF..The mechanical models of cantilever MMPF sensors were derived based on their established static and dynamic constitutive equations. Using the charges on the electrodes of an MMPF sensor, the characterization of air flow can be detected. Many cantilever MMPFs can be integrated into large snesor arrays, to develop the accuracy of air flow measurement. The mechanical models of this sensor arrays were derived. The sensing properties of MMPF air flow sensors were studied experimentally..This study can obtain the theroretical foundation for future research and usage of MMPF sensor.

蟋蟀等昆虫能够用尾部纤维状的毛发感受器，感知周围环境的气流变化，判断来犯天敌的追捕方向，躲避天敌的追捕。感受器中的纤毛和神经元相连，呈悬臂梁结构，纤毛弯曲时引起神经元产生刺激信号，大脑通过刺激信号判断周围气流的变化。.本课题模仿昆虫的毛发感受器结构，在含金属芯压电纤维的表面喷镀多个电极，制备多电极含金属芯压电纤维（MMPF），将悬臂梁结构的MMPF用作仿生气流传感器，测量周围的气流变化。首先，建立MMPF静态和动态的力、电耦合模型；在此基础上，建立MMPF参数测试模型，通过测量相关参数，表征MMPF的压电、介电和机械性能；建立悬臂梁结构MMPF气流传感模型，根据各表面电极产生的电荷，测量周围气流的变化；把多根MMPF排成阵列，建立传感模型，测量周围气流流场的变化；搭建实验系统，测试MMPF的气流传感性能，并验证传感模型。本课题的研究将为MMPF仿生气流传感器的研究和应用打下理论与技术基础。

基于仿生学的原理，模仿昆虫毛发感受器的结构，设计制备了两类含金属芯压电纤维传感器，并表征了纤维的形貌。分别建立了气流和振动传感模型，并对其进行了实验验证，实验结果与理论分析结果基本吻合。具体内容如下：.（1）利用压电陶瓷粉，采用模具成型方法，设计制备了悬臂梁结构的含金属芯压电陶瓷纤维传感器。其外表面完整、无裂纹，晶粒发育良好，颗粒细小，组织分布均匀，气孔少，致密度好。.（2）利用聚偏氟二乙烯颗粒 (PVDF)，采用熔融挤压法，设计制备了悬臂梁结构的含金属芯PVDF压电纤维传感器。其金属芯的居中性较好、金属芯和PVDF的粘合较好、表面较光滑、内壁平整。实验发现表面越粗糙的金属芯，越容易拉制出这种纤维。拉制使PVDF中的α相转化为β相，提高了压电纤维压电传感能力。.（3）根据涂镀表面电极片数的不同，设计制备了表面部分电极含金属芯压纤维(PMPF)传感器、表面对称电极含金属芯纤维(SMPF)传感器、表面多电极含金属芯纤维（MMPF）传感器。金属芯用做负极，表面电极做正极，设计了极化电路。为实现这种纤维传感器的传感性能，设计了传感电路。.（4）建立了PMPF、SMPF和MMPF这3种悬臂梁结构传感器的气流传感模型，并通过实验进行了验证。得出了这3种纤维传感器可以判断气流的大小和方向（ “8”字图和交叉“8”字图）；气流的大小与这3种纤维传感器输出电荷之间的关系；各自的共振频率。.（5）建立了PMPF、SMPF和MMPF这3种悬臂梁结构传感器的振动传感模型，并通过实验进行了验证。得出这3传感器可以感知基体结构的振动频率；基体结构的不同的振动信号（像正弦、余弦）；基体结构的振动的方向；基体结构振动幅值的变化与他们输出电荷之间的关系。.（6）建立了表面4电极含金属芯压电陶瓷纤维的空间阵列的气流传感模型，并应用于感知空间3维的冲击气流，通过实验验证了传感模型。得出了这种纤维组合对3维冲击气流的速度和方向的具有较好的传感能力。得出纤维在气流速度不变时，纤维输出信号落在一个球面上的结论。