Surface acoustic wave(SAW)gas sensing technology has the characteristics of high sensitivity,fast response,miniaturization and lightweight because of its unique acoustic sensing structure and force-acoustic-electric physical field coupling sensing mechanism,which makes it gradually become one of the emerging gas sensing tech-nologies that people pay close attention to.Based on the SAW propagation and sensing theory,this paper introduces in detail the research progress of SAW gas sensing effect and mechanism,sensor device design and preparation,sen-sor signal acquisition and processing,etc.Besides,the potential application of SAW gas sensors in many fields such as new energy,aerospace,national defense,industrial control and intelligent manufacturing and its development trend are discussed.
A method based on ferroelectric dipole to enhance surface charge density of triboelectric generator was proposed. By using the ferroelectric properties of polyvinylidene fluoride (PVDF), a positive charge trap was formed in the triboelectric layer to enhance the electric generating performance of the triboelectric material, so as to improve the surface charge density of the triboelectric nanogenerator. The PVDF film was fabricated by casting and uniaxial tensile process, and integrated into the triboelectric nanogenerator with vertical separation structure. The influences of the embedding direction, thickness and polarization intensity of the PVDF film on the output of the triboelectric nanogenerator were systematically studied. The results showed that the embedded PVDF piezoelectric film with a thickness of 100 µm and a maximum polarization electric field of 90 MV/m increased the peak power of the triboelectric nanogenerator by 2.6 times. This work has provided a new insight into regulating the properties of the triboelectric nanogenerator.
Abstract In the article, the design of a piezoelectric stick-slip rotary motor is proposed that can be used as the rotary drive part of a micro-nano operation. First, a force-coupled stator based on a flexible mechanism with a diameter of 23 mm was designed. Based on the designed stator, the structure of the rotary motor is constructed and its motion steps are analyzed. Then, finite element analysis is performed. Finally, the performance of the motor is tested and conclusions are drawn. The simulation and experimental results show that the developed motor performs well.
针对惯性约束激光核聚变（ICF）靶零件夹持和装配过程中存在的重载荷与高检测分辨率之间的装配难题，该文提出了一种基于双轴旋转结构的微装配方法。首先通过分析装配目标器件（铝套筒，金腔和半腔）的特点，制定了精密装配总体结构方案。然后介绍双轴旋转装置并对相应的传感器进行标定，并进一步对集成传感器的双轴旋转装置进行角度偏转测试，可检测最小0.01°的偏转。实验表明，该双轴旋转装置能灵敏地检测到微小的偏转，并且传感器对双轴旋转具有“置零”的能力，通过该装置可在无视觉引导的情况下完成目标件的装配。
传统的系统级标定方法是将温箱压缩机、转台电机等环境引起的随机噪声视为白噪声,而实际过程中输出信号具有非平稳和非线性特征.最小二乘拟合法是一种线性回归方法,利用该方法求解的误差系数成为制约光纤捷联惯导系统实现高精度的关键因素之一.针对上述问题,该文提出了一种基于希尔伯特-黄变换的捷联惯导系统级标定改进算法.通过希尔伯特-黄变换去除惯性仪表原始输出信号中的高频随机噪声,再利用系统级标定法计算惯性测量单元(IMU)误差参数.经多组试验证明,该方法能够有效提高IMU误差参数辨识的准确性,1 h的动态导航位置误差相对减少约 10%.
