A whispering gallery mode strain sensor based on microtube resonator

A novel whispering gallery mode (WGM) strain sensor based on microtube has been proposed, where perceiving strain variations are reported via the dynamical regulation of a whispering gallery mode. The WGMs in the microtube resonator were evanescently excited by a micro-nano fiber fabricated by the fusion taper technique. The structural changes of microtubes under axial strain were simulated with finite element software, and the effect of microtube wall thickness on strain sensitivity was systematically studied through experiments. The experimental results show that the strain sensitivity of thin-walled microtube is found to be 1.18 pm/με and the Q-factor in the order of 4.4×104. Due to its simple fabrication and easy manipulation as well as good sensing performance, the microtube strain sensor has potential applications in high-sensitivity optical sensing.     

MEMS加速度计混合误差标定补偿方案

针对微机电系统(MEMS)加速度计在实际使用过程中存在非正交零偏误差和温度漂移误差的问题,提出了一种混合误差标定补偿算法。算法通过分析加速度计温度与误差的关系,在不同温度区间下建立加速度计输出的误差模型,在每个温度区间采用十二位置校准法对加速度计的非正交零偏误差进行标定补偿,得到精确的零偏和刻度因子,同时采用最小二乘法拟合零偏和刻度因子与温度的一维关系函数,最终实现不同温度区间下的动态误差补偿。实验结果表明,本算法可使加速度计输出的精度提高1个数量级,补偿效果明显。     

A temperature-insensitive polarization filter and a neotype sensor based on a hybrid-circular-hole microstructured optical fiber

A temperature-insensitive polarization filter and a neotype sensor based on a hybrid-circular-hole microstructured optical fiber (MOF) are proposed. Numerical investigations demonstrate that the x polarized component of silica core mode can couple to the cladding mode in the researched wavelength, while the y polarized component would not. Furthermore, the resonant region can be controlled by changing the diameters or coordinates of the air holes, and the MOF has good performance on stability of temperature. Moreover, the hybrid-circular-hole structure is propitious to selectively integrate different functional materials. Two different materials are integrated into this proposed MOF, the application of the Sagnac interferometer in temperature sensing is studied, and two groups of dips would be observed in the transmission spectra, which have different temperature sensitivities. Therefore, the proposed MOF can be used as a flexible temperature-insensitive polarization filter or potentially applied to a two-parameter sensor.     

Design and characteristic research on side-polished fiber fluid sensing system

A novel fluid sensing system based on side-polished optical fiber (SPOF) is proposed, which realizes the fluid replaceability and effective refractive index (RI) sensing characteristics. Numerical investigations demonstrate that the photonic bandgap effect can be obtained if the RI of liquid is higher than that of substrate material in the wavelength range studied. The relationship between bandgap edge wavelength and RI is studied theoretically. The SPOF with a depth of 57 μm is used in the experiment to realize the construction of the fluid channel. After filling three different liquids, the result shows that the wavelength of the bandgap edge has a red shift with RI increased, which is nearly linear in the RI range of 1.56—1.6 with a sensitivity about 5 543.64 nm/RIU. The proposed sensing system can be flexibly applied to the field of fluid characteristic sensing such as biochemical solution characteristic detections.     

基于PSO优化RBF神经网络的MEMS陀螺温度补偿

针对微电子机械系统(MEMS)陀螺温度变化影响其零偏误差的问题,提出了一种基于粒子群优化(PSO)和径向基函数(RBF)神经网络的陀螺零偏补偿方法.通过RBF神经网络对预处理后的陀螺零偏的温度误差建立模型,用PSO 搜索RBF神经网络的最优参数来提高其泛化能力后,将PSO-RBF神经网络最优参数用于补偿陀螺零偏.实验结果证明了该算法的有效性,经PSO-RBF神经网络算法补偿后,MEMS陀螺零偏的最大误差从0.046(°)/s减小到0.003 4(°)/s,标准差从0.042 7(°)/s减小到0.001 3(°)/s,有效提升了陀螺的零偏稳定性.     

基于MEMS传感器组合的行人室内高度定位算法

针对气压计易受环境温度影响的问题,该文提出了一种基于微机电系统(MEMS)加速度计和气压计融合的行人室内高度定位算法。该算法分别利用x轴加速度计的峰值特征和z轴加速度计的四分位距特征进行上、下楼判定;然后利用滤除掉气压突跳点的气压计数据进行高度解算;最后行人平走时,将解算高度修正到半层楼高的整数倍,减少高度误差。实验结果表明,该文提出的行人室内高度定位算法不易受环境温度的影响,解算高度与实际楼层高度的误差小于2 m,可将人员定位到正确楼层。     

功能梯度界面层模型断裂问题研究进展

对功能梯度界面层模型的由来以及模型断裂问题的研究现状和方法进行了综述,介绍了采用何种函数形式以表征界面层内材料力学属性,并且对该模型的应用前景和发展趋势进行了展望。     

Numerical simulation of a neotype fluidic sensing system based on side-polished optical fiber

Theoretical design of a neotype fluidic controlling sensor system based on side-polished optical fiber is proposed. Numerical investigations demonstrate that the higher birefringence and resonance coupling can be achieved by flexible design of the polishing shape and depth in the research wavelength. The fluidic system is beneficial to selective integration of functional materials. The material is integrated into the fluidic system, which can achieve a birefringence up to 6.98×10-5, and the application of Sagnac thermometer in temperature sensing is studied, and a group of dips with different temperature sensitivities would be observed in the transmission spectra, which is about 1.6 nm/°C by calculating. furthermore, by introducing resonant coupling, single mode single polarization at 1 310 nm is realized. The refractive index (RI) response of the sensing system for a low RI range of 1.39—1.37 is approximately linear, and exhibits a sensitivity of 6 338 nm/RIU. The results show that the proposed neotype fluidic controlling system can be used as a flexible polarization filter or as a potential two-parameter sensor.     

基于MEMS惯性传感器时域特征的人体行为识别

提出了一种基于微机电系统(MEMS)惯性传感器组合系统的高精度实时人体行为识别算法。算法选取一个2 s的滑动时间窗作为特征提取窗口,提取惯性传感器组合系统输出的时域特征作为特征参量,采用基于平衡决策树的支持向量机对人体不同行为模式进行分类识别。在实验室自主研发的可穿戴智能终端平台上进行测试,结果表明,在识别时间缩短到2 s/次的条件下,对5种行走类行为模式和5种非行走类行为模式的识别率均可达88%。与现有算法相比,该算法的实时性和精度得到明显提高,且拓展了模式识别的种类。     

基于MEMS加速度计的优化九位置校准算法

针对传统的加速度计标定法对高精度转台依赖高的问题,提出一种基于微机电系统(MEMS)加速度计的优化九位置标定算法。该算法考虑加速度计的非线性因子和电子串扰效应,通过采集9个位置的静态加速度计输出数据,即可对加速度计零偏、刻度因子和安装误差等系数进行高精度快速校准,摆脱了对传统转台的依赖。实验结果表明,基于MEMS加速度计的九位置标定算法有效解决了加速度计非线性问题,减低了电子串扰效应对加速度计的影响,加速度计的误差精度由8.48×10-3g(g=9.8 m/s2) 减少到5.1×10-4g,证明该九位置标定算法的可行性和有效性。