六维动态气动力压电测量原理与技术研究

For the great demands of aerodynamic force measurement for the hypersonic vehicle in the wind tunnel experiments in the aerospace field, it should be carried out that the research on the principle and technology of piezoelectric measurement for six-dimensional aerodynamic forces based on LGS and quartz crystal. The piezoelectric effect of LGS crystal is deducted and the elements values of the piezoelectric coefficient matrix are determined. For the LGS wafer with specific cutting parameters, the constitutive relation of “force - charge” is discussed. Under the multidimensional forces acting, the rules of the stress distribution on the wafer are derived as the variables of the stiffness of crystal and connecting component. The mapping relationship between multidimensional forces and charges of local area on wafer is researched and built up. With analyzing the influence factors of each force and the related design parameters of the piezoelectric sensor, the optimization mathematic model is studied and built about the measurement range and the design parameters. Breaking the traditional design method based on the overall charge of wafer surface with one electrode, the process method of multi electrodes arrangement and position keeping in small region is researched. The piezoelectric sensor with single crystal group is developed that could measure multidimensional, even six dimensional forces. Considering the effect of serious temperature gradient and stress wave in the hypersonic aerodynamic measurement environment, the experiments and simulation research on the piezoelectric measurement is carried out with those factors acting, to improve the measurement accuracy. Through the research of this project, a new way to design the piezoelectric sensor is opened up based on one wafer surface arranged multi electrodes. And a new method is provided for the measurement of hypersonic multidimensional dynamic aerodynamic forces in wind tunnel experiment.

面向航空航天领域高超声速飞行器设计对多维动态气动力精确测试的重大需求，开展基于LGS、石英晶体的六维动态气动力压电测量原理与技术研究。进行LGS晶体的正压电效应研究，确定压电系数矩阵各元素的具体数值，针对特定切型的压电晶片建立 “力-电荷量”本构关系；以晶片刚度与封装构件刚度为变量，揭示六维力作用下晶片与构件间界面应力分布规律，得到六维力与晶片局部区域电荷量之间的映射关系；分析传感器各维量程及维间互扰与相关设计参数的影响因素，建立其优化数学模型；突破以晶片表面整体电荷提取为基础的传感器设计常规，开展晶片面域多电极布置与定位的工艺方法研究，开发单晶组六维力压电传感器；进行大温度梯度、应力波作用下的压电测量影响实验与仿真分析研究，提高压电测量在高超声速气动力实验环境的测试精度。通过本项目研究，开创基于单晶片多电极布置的压电传感器设计新思路，为高超声速多维动态气动力风洞实验提供一种新的测量方法。

压电式传感器以其优异的动态性能，以及日益提高的测量精确度，在高精密加工、高性能部件的力学量性能测试中发挥关键作用。传统的压电传感器设计以压电晶体固有的拉压效应、剪切效应为基础，开发出压电式三分力传感器及六维力测试平台，体积较大，限制了在某些对空间要求较高的领域内的应用，如大缩尺比的风洞试验模型。本项目在压电晶体基本效应研究的基础上，深入探讨六维力作用下晶体各个表面的电荷分布，利用各向异性弹性力学的解算方法，建立六维力与面域内各部分电荷输出的函数关系，进而使用一个核心的压电晶体，实现狭小空间内多维力测量。.本项目研究过程中，针对标准坐标系下的压电晶块及形成的六个表面，建立了六维力与局部区域电荷量输出之间的映射关系，开发出基于面域“分区”布置电极与刚度匹配的六维力单晶组，揭示了晶片局部区域电极间电荷的互影响规律及向间干扰影响机制，研究说明利用压电晶片叠堆或压电晶块在原理层面可实现六维力测量；利用该原理开发出了多维力压电传感器，结合高速飞行器表面气动摩擦阻力测量应用需求，开发了小力值摩擦阻力与大幅值正压力测量传感器，探讨了该传感器测量过程中环境因素、自身向间干扰的影响，并提出了主动支撑、物理隔热等精度保障措施，精度提高60%以上；开发出基于电磁吸力的毫牛级标准小力获取装置，克服了传统砝码加载过程中的损耗，实现了该压电传感器的静态标定，标定结果表明线性度5%以内，利用锤击法获取的传感器固有频率在1kHz以上。.本项目研究成果证明利用多维力与晶面面域电荷输出之间的规律可实现六维力测量，改变了传统上利用压电方法测量六维力仅从利用三分力传感器空间布置的方法，从而大大拓展了压电式六维力测量的应用范围，为某些关键领域的多维力测量急需提供了可行的技术和方法。本项目研究将结合实际应用需求，在环境适应性、精度提高等方面持续开展研究，为我国重点行业发展作出应有的贡献。