提高无源声表面波扭矩敏感单元温度稳定性和传感系统响应速度的关键理论和技术研究

针对目前声表面波(SAW)扭矩传感系统中因敏感单元温度特性和阅读器工作方式导致的测试精度低、动态特性差的现实问题，结合申请者前期研究基础，本项目着力研究提高扭矩敏感单元温度稳定性和系统响应速度的关键理论和方法。拟采用ZnO/电极/石英层状结构，通过格林函数、摄动理论和有限元仿真建立层状结构的扭矩敏感理论模型，分析多层结构参数对温度、扭矩敏感特性的影响，优化设计结构参数实现温度敏感的自补偿；从SAW谐振器响应信号着手，建立信号熵能量与谐振器Q值之间的函数关系模型，揭示响应信号随激励信号的变化规律，为SAW有效激励检测算法和快速查询算法设计提供理论基础和技术路线；研究基于多频复合激励技术的多谐振器同步阅读技术方案和分析算法，以适应差分式SAW扭矩传感器的快速解调。基于上述技术使设计的传感系统测量不确定度优于1%FS(k=2，温度范围-20℃～85℃)，响应速度达到100Hz，满足扭矩测量要求。

Due to the fact that the temperature characteristics of the surface acoustic wave (SAW) sensing element is unstable and the interrogation cycle is long, the performance of existing SAW dynamic torque sensor is poor and the sensing system can’t be used to measure the dynamic torque under different temperature fields. With the accumulated research experience during the SAW torque sensor study, the temperature stability of SAW sensor is improved and the technical problems of SAW resonant (SAWR) frequency fast scanning and multi-SAWRs interrogation, which have a great impact on the response of SAW torque sensor, are mostly solved. The laminated composite structure of ZnO/electrode/quartz was adopted. The theoretical model of torque sensing was established according to the Green function, FEM and perturbation theory. The impact of the structure parameters of the composite on the temperature and torque sensitivity was analyzed. The effect of temperature self-compensation was realized via optimizing the structure parameters. By analyzing the SAWR response, the relationship between the SAW energy entropy and the quality factor of SAWR was constructed and the response of the SAWR to an exciting signal was derived. A SAWR response detection method was proposed and a fast searching algorithm was designed. Based on the multi-frequency composite exciting technique, the technology solution of multi-resonators synchronous exciting and the corresponding analysis algorithm were studied. The reliability of the system was improved by doing all above. The SAW torque sensing prototype was developed with a uncertainty of 1%FS (k=2, temperature varying in the range: -20℃～85℃) and a response speed 100Hz which meets most of the requirements of the torque measurement.