基于压电双晶片的风速辨识系统
Wind Speed Identification System Based on Piezoelectric Bimorphs

为了感知飞行器外部流场，间接获得航速和姿态角等飞行参数，提出了一种基于压电双晶片阵列的风速辨识集成部件。在尽可能减小空气动力学特性影响的情况下，设计了一种双晶片两轴对称的飞行器头部风传感实物模型，由4片双晶片阵列组成。首先，在风洞实验中采集单片双晶片的感应电信号，经过电荷放大器、NI数据采集卡与Labview虚拟仪器分析软件，利用最小二乘法获得各自压电双晶片的感应电压（均方根值）与风速（矢量）之间的函数关系；其次，建立风速辨识集成部件的双变量（风速大小与风向角）传感函数模型，由此反求风速大小和方向。实验结果表明，所设计的风速辨识压电集成部件在风洞内可实现风速的二维测量，采样时间为5s时，其传感精度在3%（风速大小）和3°（风向角）以内，最高分辨率可达0.5%（风速大小）和0.55°（风向角）。此应用于飞行器上的风速辨识集成部件可以快速感知风速大小和方向，其传感函数模型的精度满足外部环境风速辨识的要求，为今后飞行器传感系统集成化与小型化奠定理论与实验基础。
In order to sense external flow field such as the change of wind speed, an integrated system of wind identification components based on piezoelectric bimorphs array is proposed to obtain the flight parameters such as speed and attitude angle. A physical aircraft head model with 4 pieces of wind bimorphs’ sensors is designed as symmetric structure, and the model has little effect on the aerodynamic characteristics. First of all, in the wind tunnel test, the inductive signals of single bimorph are measured by a charge amplifier, NI data acquisition card and Labview virtual instrument analysis software. The least squares algorithm is used to obtain the functional relationship between the inductive voltage (root mean square) of each piezoelectric bimorph and wind speed (vector). Then, the sensing function model of the two variables (the wind velocity and the angle) of wind speed identification system is established to calculate the wind velocity and the angle. The experimental results demonstrate that the design of the wind speed identification of piezoelectric integrated components can realize a twdimensional measurement of wind speed in the wind tunnel. When the sampling time is 5 s, the sensing accuracies of velocity and angle are smaller than 3% and 3° respectively. Further, the highest resolution can reach 0.5% (velocity) and 0.55°(angle). The integrated components of wind speed identification used in aircraft can quickly sense the wind velocity and direction, the accuracy of sensing function model can meet the requirements of the wind speed identification of external environment. All these lay a theoretical and experimental foundation for the future integration and miniaturization design of aircraft sensor system.