T型光电转台多传感器结构布局及多光轴平行性调校研究

针对当前一些T型光电转台多传感器结构布局不合理、多光轴平行性调校困难等问题,分析了安装多传感器的光具座结构设计对多光轴平行性的影响,提出了T型光电转台多传感器结构布局的原则和多光轴平行性调校方法。并且把该设计思想、布局原则和调校方法应用于某T型光电转台上。结果表明,该T型光电转台具有多传感器结构布局合理,多光轴平行性容易调校,多光轴平行性和稳定性高等优点。

基于多传感器的智能农田多源信息采集系统

为了提高农田信息数据的采集效率与精准性,研究一种基于多传感器的智能农田多源信息采集系统。结合农田的运营特征与基本需求,确定系统所需的硬件设施,搭建智能农田多源信息采集系统的基本架构,应用卡尔曼滤波技术,对采集数据进行预处理,识别农田多源信息的基本特征,实现基于多传感器的农田多源信息智能化采集。实验结果表明,对于随机大小不同的10组农田多源信息数据包,设计系统完成分析处理并成功采集的运行时间,最大值为5.57s,平均值为4.534s,设计系统采集的温度、湿度、CO_(2)浓度以及土壤水分数据的平均相对误差分别为0.87%、1.02%、0.65%、0.71%,均在实际工程的最低要求2%之内。

多传感器管理结构及功能模型探讨

摘要:首先分析多传感器管理的三种结构,根据混合式结构的特点,探讨多传感器管理的混合式结构模型;其次从实际出发,对多传感器管理的功能模型进行了讨论,并简要描述各部分的作用;最后分析多传感器管理的层次。文章对上述问题的探索,对合理设计多传感器管理系统有一定的意义。

基于多传感器融合技术的煤矿安全监控系统研究

单一传感器只能获得煤矿井下部分环境信息,不能够有效和全面地对整个矿井瓦斯环境进行准确检测,从而可造成煤矿井下瓦斯信息的不准确传达以及误报、漏报等问题,针对目前矿井单一传感器的局限性,采用D-S算法的多传感器融合技术,研究提出一种基于D-S算法的多传感器融合技术,此技术应用于矿井瓦斯监控系统中,系统运用了分布式多传感器体系结构和二级融合模型的方法对煤矿井下多传感器数据进行融合,研究得出多传感器融合技术的使用能够提高了整个监控系统的可靠性以及降低了矿井瓦斯事故的发生,基于D-S算法的多传感器融合技术的发挥为矿井瓦斯安全监控提供了技术支撑,在瓦斯监控系统中具有良好的推广应用价值。

多传感器线结构光视觉测量系统全局校准

针对现有多传感器线结构光视觉测量系统全局校准过程中通常需要三维测量设备、校准过程复杂等问题,提出了一种基于一维靶标的多传感器线结构光视觉测量系统全局校准方法。此方法以一维靶标为中介,首先由每个线结构光视觉传感器得到光条与一维靶标相交点在各自测量坐标系下的三维坐标,然后由交比不变性得到相交点在一维靶标坐标系下的坐标,进而得到不同相交点的空间距离,将一维靶标在合适位置摆放多次,以相交点之间的空间距离为约束条件,建立以旋转矩阵和平移矢量为参数的优化目标函数,通过非线性优化算法求解出各线结构光视觉传感器间的旋转矩阵与平移矢量。此方法不需要借助复杂靶标及三维测量设备,校准过程简单,并且能达到较高的校准精度。实验结果表明,全局校准的均方根(RMS)误差优于0.1mm。

多传感器交叉提示技术发展现状与研究

总结了多传感器交叉提示的含义、方法及技术应用研究现状,并给出了传感器交叉提示的内涵;提出了多传感器交叉提示技术的主要研究内容,研究了多传感器交叉提示的条件、在信息融合系统中的交叉提示过程以及具有交叉提示功能的多传感器协作管理结构;指出了多智能体技术是研究交叉提示技术的基本方法和发展趋势。

Integrity assurance of GNSS-based train integrated positioning system

This paper presents a novel Autonomous Integrity Monitoring and Assurance （AIMA） scheme for integrity assurance of the GNSS-based train integrated positioning system. In this scheme, integrity assurance strategies are combined with a three-stage hierarchical architecture, considering the coupling effects among sensor collection, sensor fusion and matching decision level in train integrated positioning. In sensor collecting stage, the AIMA scheme deals with sensor faults and failures with a PCA-based fault detection, diagnosis and isolation approach. In multi-sensor fusion stage, a novel cubature point H0o filter is presented to enhance the fault tolerance capability, and a hybrid approach is applied to indicating and monitoring the protection level of position estimation, concerning both the estimating covariance and measurement slopes. In map matching stage, hypothesis testing with specific test statistic is carried out to determine effectiveness of positioning results. Position calculation will be invalid with an alarm triggered if the specific integrity criterion is not satisfied in any stage. Since independent solutions are applied in AIMA, integrity assurance is closely coupled with information processing in train integrated positioning. Numerical results of the three cases correspond to the hierarchical architecture with field data and simulations are presented to illustrate features and applicability of the proposed AIMA scheme and specific solutions.

High conductive graphene assembled films with porous micro-structure for freestanding and ultra-low power strain sensors

Graphene emerges as an ideal material for constructing high-performance strain sensors,due to its superior mechanical property and high conductivity.However,in the process of assembling graphene into macroscopic materials,its conductivity decreases significantly.Also,tedious fabrication process hinders the application of graphene-based strain sensors.In this work,we report a freestanding graphene assembled film(GAF)with high conductivity((2.32±0.08)×105 S m-1).For the sensitive materials of strain sensors,it is higher than most of reported carbon nanotube and graphene materials.These advantages enable the GAF to be an ultra-low power consumption strain sensor for detecting airflow and vocal vibrations.The resistance of the GAF remains unchanged with increasing temperature(20-100℃),exhibiting a good thermal stability.Also,the GAF can be used as a strain sensor directly without any flexible substrates,which greatly simplifies the fabrication process in comparison with most reported strain sensors.Additionally,the GAF used as a pressure sensor with only^4.7μW power is investigated.This work provides a new direction for the preparation of advanced sensors with ultra-low power consumption,and the development of flexible and energy-saving electronic devices.

Magnetic field sensor based on peanut-shape structure and multimode fiber

An all fiber magnetic field sensor with peanut-shape structure based on multimode fiber(MMF) is proposed and experimentally demonstrated. The sensing structure and magnetic fluid(MF) are both encapsulated in capillary, and the effective refractive index of MF is affected by surrounding magnetic field strength. The measurement of magnetic field is realized by observing the wavelength drift of interference peak. The transmission spectrum generated by Mach-Zehnder interferometer(MZI) includes core-core mode interference and core-cladding mode interference. Experimental results demonstrate that the core-cladding mode interference is sensitive to magnetic field, and the magnetic field sensitivity is 0.047 8 nm/mT. In addition, two kinds of interference dips are sensitive to temperature, and the sensitivities are 0.060 0 nm/°C and 0.052 6 nm/°C, respectively. So the simultaneous measurement of magnetic field strength and temperature can be achieved based on sensitivity matrix.

Multimode Interference Refractive Index Sensor Based on Coreless Fiber

A multimode interference refractive index （KI） sensor based on the coreless fiber was numerically and experimentally demonstrated. Two identical single mode fibers （SMF） are spliced at both ends of a section of the coreless fiber which can he considered as the equivalent weakly guiding multimode fiber （MMF） with a step-index profile when the surrounding refractive index （SKI） is lower than that of the coreless fiber. Thus, it becomes the conventional single-mode multimode single-mode （SMS） fiber structure but with a larger core size. The output spectra will shift along with the changes in the SKI owing to the direct exposure of the coreless fiber. The output spectra under different SKIs were numerically studied, as well as the sensitivities with different lengths and diameters of the coreless fiber. The predication and calculation showed the good agreement with the experimental results. The proposed RI sensor proved to be feasible by verification experiments, and the relative error was merely 0.1% which occupied preferable sensing performance and practicability.

Multi-type sensor placement and response reconstruction for structural health monitoring of long-span suspension bridges

This study is devoted to the experimental validation of the multi-type sensor placement and response reconstruction method for structural health monitoring of long-span suspension bridges. The method for multi-type sensor placement and response reconstruction is briefly described. A test bed, comprising of a physical model and an updated finite element （P-E） model of a long-span suspension bridge is also concisely introduced. The proposed method is then applied to the test bed; the equation of motion of the test bed subject to ground motion, the objective function for sensor location optimization, the principles for mode selection and multi-type response reconstruction are established. A numerical study using the updated FE model is performed to select the sensor types, numbers, and locations. Subsequently, with the identified sensor locations and some practical considerations, fiber Bragg grating （FBG） sensors, laser displacement transducers, and accelerometers are installed on the physical bridge model. Finally, experimental investigations are conducted to validate the proposed method. The experimental results show that the reconstructed responses using the measured responses from the limited number of multitype sensors agree well with the actual bridge responses. The proposed method is validated to be feasible and effective for the monitoring of structural behavior of longspan suspension bridges.