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。     

自适应卡尔曼滤波在磁干扰姿态测量中的应用

针对姿态测量系统陀螺仪漂移、周围局部磁场干扰制约姿态测量精度的问题,提出一种基于四元数的自适应卡尔曼滤波(q-AKF)的方法。该方法利用陀螺输出建立姿态解算误差角的状态方程,以磁强计输出构造自适应测量噪声协方差矩阵。仿真结果表明,相比无损卡尔曼滤波(UKF)算法和扩展卡尔曼滤波(EKF)算法,采用q-AKF算法补偿得到的姿态角误差不大于0.5°。q-AKF算法对磁强计进行补偿,能够有效抑制陀螺的漂移误差,提高磁干扰环境下姿态解算精度,具有较高的工程应用价值。     

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.     

基于固态振动陀螺的短期偏置稳定性研究

该文研究了固态振动陀螺的短期稳定性.从固态振动陀螺的动力学方程入手,讨论了影响固态振动陀螺短期偏置稳定性的因素,计算结果显示,暂态解误差是影响陀螺短期偏置稳定性的主要因素,针对暂态解的特点采用低通滤波器进行滤波.仿真结果表明,低通滤波器能有效抑制输出值中的误差信号,并对压电振动陀螺进行滤波实验,实验结果同仿真结果吻合很好,由此可得出该模型的正确性和滤波方案的可行性.     

微航姿仪的磁力计标定算法及误差补偿研究

针对目前磁力计标定算法中存在磁干扰或噪声导致航向角测量误差等问题,提出了一种改进的磁力计标定算法。该算法考虑磁力计安装误差和外界磁干扰,提出改进的磁力计误差模型;同时运用BP神经网络训练软磁干扰下的磁航向与真实航向之间的非线性关系,降低了非线性误差。通过仿真和实验验证,算法有效地解决了磁力计误差补偿问题,降低了软硬磁干扰对航向角的影响,得到较精确的航向角,误差范围在±1°内,证明了改进误差补偿算法的可行性和有效性。     

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。     

基于小波包-神经网络的MEMS加速度计零漂补偿

针对微机电系统(MEMS)加速度计零位漂移大的问题,研究了一种基于Birgé-Massert(BM)阈值小波包降噪的广义回归神经网络对MEMS加速度计零位漂移进行非线性抑制的新方法。该方法首先利用BM阈值小波包滤除零位漂移中的噪声,然后利用广义回归网络对非线性数据的无限逼近原理,来建立MEMS加速度计的零漂模型。将实测数据代入模型,计算结果表明,经过该模型补偿后的零漂输出结果同未经补偿、最小二乘拟合补偿、未经滤波建模补偿相比,均值分别减小97.4%、67.8%、67.8%,均方差分别减小87.4%、87.5%、90.9%;利用训练后的模型进行实时补偿延迟时间为10-5 s。分析结果证明了基于BM阈值小波包降噪滤波技术的广义回归网络组合模型的有效性和合理性。