光桥平衡补偿型光纤双向应变位移传感器

在光桥平衡补偿型光纤双向应变位移传感器中,光源发出的光被3dB耦合器分束到拉敏光纤和参考光纤或压敏光纤和参考光纤中,而这些调制光和参考光由两光探测器分别进行测量。通过自相关损耗,可有效消除光纤应变位移传感器中光源功率波动、光纤传输损耗的变化以及光探测器灵敏度的漂移所引起的误差。微位移架上的位移实验表明:误差为0.01mm。     

测试光纤光功率损耗标准的发展

在1998年8月,电信行业协会（TIA）发布了T1A526—14-A标准,即安装的多模光纤线路的光纤光功率损耗测试标准,该标准介绍了采用以发光二极管或激光作为光源的功率计来测试多模光纤光功率损耗（衰减）的各项规格。     

基于金属热膨胀式光纤温度传感器的设计

介绍了金属热膨胀式光纤温度传感器的设计,利用金属件的热膨胀的原理,通过绕制在金属件上的光纤损耗产生变化,当光源输出光功率稳定的情况下,探测器接收光功率受温度调制,通过光电转换,信号处理,完成温度的换算.传感器以光纤为传输手段,以光作为信号载体,抗干扰能力强,测量结果稳定、可靠,灵敏度高.     

光纤传输设计中的距离计算

光纤通信系统性能受光纤带宽及其传输损耗的影响,而光纤的传输损耗特性是决定光纤网络传输距离、传输稳定性和可靠性的最重要因素之一。针对上述问题,文章在对光：纤链路损耗进行分析的的基础上,给出了光纤传输距离计算的方法。     

微弯光纤传感器位移灵敏度研究

根据光纤模式耦合理论,光纤微弯时光纤中的传输光有光功率损耗,对微弯光纤传感器出射光强进行分析、测量,实验得出了位移灵敏度与微弯周期的关系,对应用微弯光纤组成分布式光纤测试系统的传感器具有重要意义。     

基于光纤微弯原理的应变式传感器技术研究

光纤作为近代高科技的产物,在国民经济的诸多领域（尤其在通信领域）得到了广泛的应用．。在绝大多数的应用场合,总是力求最大限度地降低光纤的传输损耗,而微弯传感器技术恰恰利用了外界扰动与光纤的传输损耗关系来实现传感器功能。本文阐述了光纤微弯损耗机理和光纤微弯传感器的工作机理,在此基础上提出了光纤微弯应变传感器系统设计模型,并据此设计了光纤微弯应变传感器系统设计模型,并据此设计了实验系统,长期的实验结果表     

光纤智能复合材料纤维自动铺放制造工艺研究

光纤智能复合材料能对复合材料内部应力和微小损伤实时在线监测,具有良好的稳定性和可靠性.目前,光纤智能复合材料制造过程中光纤大多采用手工方法植入,其效率低、一致性差,针对此问题提出并研究了基于纤维铺放技术的光纤智能复合材料自动化制造工艺,将光纤的植入过程与纤维丝束铺放过程相结合,实现光纤智能复合材料的自动制造.通过实验确定了光纤植入过程中输送压辊材料与输送压紧力、铺放压紧力和加热温度等工艺参数,研究表明:当光纤平行于碳纤维预浸带方向植入时,选取硅橡胶输送辊,输送压紧力为15N,铺放压紧力为300N,加热温度为80℃时,植入到复合材料的光纤损耗较小,且光纤光栅反射谱形状保持稳定,能够保证植入后光纤光栅的传感特性.     

基于波长选择型可重构光分插复用设备的IP网络的传输长度设计

针对高速大容量波分复用(WDM)网络在多点故障、变更的情况下,运行效率低、维护成本高的问题,提出使用可重构光分插复用设备(ROADM)元件来构建灵活网络.首先,给出了所用的5节点网络配置模型;然后,研究了在动态网络条件下使用ROADM的光网络损耗与传输长度间关系,提出网络传输长度设计流程;其次,基于ROADM搭建一个5节点双向光纤环路实验网络,测量了光损失特性;最后,分析实验结果,得出损耗计算值与光纤实装损耗测量值近似相等(相差0.8 dB),验证了设计的可行性,保证了节点间的可靠传输.     

超低损耗光纤助力400G传输网与5G移动网快速发展

5G网为了能够实现智能化,其与3G、4G网的核心技术支持不同,5G网的核心技术位光纤传送下的移动通信前传技术.现阶段,我国的光传输网络技术得到了进一步发展,为了促进5G移动网的快速发展需要部署400G光传输系统,其中超低损耗光纤以及大有效面积光纤能够为400G光传输系统的大规模部署起到推动作用,而5G移动网的发展也对光纤性能提出新要求.     

基于OptiSystem的WDM系统的设计与仿真

利用光波分复用（WDM）系统,将五组不同波长的光信号组合复用并耦合到光缆信号的同一根光纤中进行传输,采用光学仿真软件OptiSystem进行光发送机,光传输链路,光接收机模块的搭建和分析。本文通过改变输出光功率,光纤传输长度和光纤的损耗系数的参数,验证系统可行性,探究其对于光纤通信系统性能的影响,得出本系统最佳输出光功率,最远传输距离,和最佳光纤损耗系数参数,建立了一个可靠性良好的光纤通信系统。该系统相对于传统的光纤通信,具有更高的灵敏度和更低的误码率,对未来光纤通信技术的发展具有深远的影响。     

基于滑动时间窗的支持向量机软测量建模研究

提出了一种基于滑动时间窗的最小二乘支持向量机软测量建模方法，并针对某一工业共沸精馏塔成分估计问题，建立了合适的工业软测量模型。介绍了最小二乘支持向量机计算法和滑动时间窗的建立。并利用滑动时间窗内的数据进行系统的在线优化和周期性模型更新，提高了工业软测量模型的在线估计精度。研究结果表明，LS—SVM是一种有效的软测量建模方法。     

基于遥感GIS信息融合的测绘机器人滑动模跟踪控制系统

测绘机器人是实现测绘自动化的执行设备,测绘机器人的工作空间更为复杂,给机器人的跟踪控制工作带来较大挑战。为提高测绘机器人跟踪控制效果,设计了基于遥感GIS信息融合的测绘机器人滑动模跟踪控制系统。加设遥感信息采集器和GIS信息采集器,改装遥感GIS信息处理器以及滑动模跟踪控制器,完成硬件系统的优化设计。考虑信息结构以及信息之间的逻辑关系,构建系统数据库,为遥感GIS信息提供充足的存储空间。根据测绘任务生成机器人滑动模移动轨迹,作为机器人的控制目标。采集测绘机器人实时遥感与GIS信息,利用遥感GIS信息融合技术跟踪机器人实时位姿,比对位姿跟踪结果与生成的控制目标,计算滑动模跟踪控制量,完成系统的测绘机器人滑动模跟踪控制软件功能优化。系统测试结果表明:设计系统的控制误差平均值为1.9 m,抖振幅值为0.8 dB,具有较好的控制效果。     

Computational model for tactile sensing system with wrinkle’s morphological change

ABSTRACT

We previously developed Wrin’Tac, a tactile sensing system that can select sensing modalities by changing its morphology. In this paper, we present a computational model to estimate a wrinkle’s morphology and predict the output of embedded sensing elements in both static indentation and sliding action cases. We evaluated the wrinkle shape and the posture of the sensing element by calculating its height. The wrinkle’s mechanical change is assessed by ascertaining its stiffness under vertical indentation by a spherical indenter. The output voltages of the sensor under static indentation are calculated by the proposed model, and the experimental values have error less than 10%, which validates the accuracy of our proposed model. For dynamic sliding action, this proposed model clarified the capability of wrinkle morphology in an evaluation of such sliding action’s characteristics as the sliding direction and velocity. We also identified the role of the wrinkle’s morphology in the sensor’s sensitivity under different conditions of dynamic sliding motion, implying that this sensing system may select suitable sensitivity for specific sensation tasks. We expect this work to pave the way for assessing the role of morphological changes to tactile sensation and developing soft active tactile sensing systems.     

Chattering-Free Sliding Mode Altitude Control for a Quad-Rotor Aircraft: Real-Time Application

Nowadays, the chattering problem in sliding mode control is one of the most important points to consider in real-time applications. To address this problem, a real-time robust altitude control scheme is proposed for the efficient performance of a Quad-rotor aircraft system using a continuous sliding mode control. The sensing of altitude measurement sensing is performed by a pressure sensor in order to obtain a robust altitude control of the vehicle in hovering mode both indoor and outdoor. The altitude measurement has the advantage of introducing this state information directly in the closed loop control which should be very useful for achieving robust stabilization of the altitude control. Accordingly, we propose a sliding mode control strategy without chattering. The sliding mode control proposed removes the chattering phenomenon by replacing a sign function with a high-slope saturation function. The control algorithm is derived from the Lyapunov stability theorem. Moreover, we have assumed that the actuators are able to respond quickly and accurately and we have not enforced limits on the control signals for a real-time application. Finally, to verify the satisfactory performance of proposed nonlinear control law, several simulations and experimental results of the Chattering-free sliding mode control for the Quad-rotor aircraft in the presence of bounded disturbances are presented.     

一种基于深度学习的遥感图像目标检测算法

遥感图像分析在国土资源管理、海洋监测等领域有着极为广阔的应用前景。深度学习技术已在图像处理领域取得突破性进展,然而,遥感图像固有的尺寸大、目标小而密集等特点,使得将面向普通图像的深度学习方法用于遥感目标检测普遍存在定位不准确、小目标检测难、大图检测精度差等问题。针对上述难题, 提出了一种新型遥感图像目标检测算法DFS。与传统机器学习方法相比,DFS 设计了新的维度聚类模块、定制损失函数和滑动窗口分割检测机制。其中,维度聚类模块通过设计聚类机制优化定制先验框,提高定位精度;定制损失函数提高对船只等小目标的检测精度;滑动窗口分割检测解决大图检测精度低的问题。在经典遥感数据集上开展的实验对比表明,与YOLOv2相比,DFS算法的mAP提高了256%,小目标检测效率及大图检测效能大幅提高。     

基于触滑觉感知的智能假肢抓握控制方法研究

【】触觉和滑觉感知功能是仿生假手不可或缺的感知功能。本文在原有智能假肢的基础上,通过对触滑觉感知方法的研究,包括触滑觉传感器的选型、后续测量电路的设计和测点布局分析等,开发了一种可以同时实现触觉和滑觉感知的智能假肢。进而,通过模糊逻辑控制方法的引入,实现了假肢的可靠抓握功能及抓握保持过程中的自适应响应控制。实验结果表明,该智能假肢可以实现假肢抓握的稳定控制,并在被抓握物体产生滑动时进行精准快速的自适应响应控制。     

Sampled-data H8 state-feedback control of systems with state delays

Sliding mode based feedback control has long been recognized as a powerful, yet easy-to-implement, control method to counteract non-vanishing external disturbances and unmodelled dynamics. Recently, research attention has focused on the development of sliding mode feedback control methods for various classes of infinite-dimensional systems. However, the existing methods are based on the assumption that distributed sensing and actuation is available, which significantly restricts their applicability to distributed process control applications. In this work, a sliding mode output feedback control method is developed for a class of linear infinite-dimensional systems with finite-dimensional unstable part using finite-dimensional sensing and actuation. Modal decomposition is initially used to decompose the original infinite-dimensional system into an interconnection of a finite-dimensional (possibly unstable) system and an infinite-dimensional stable system. Then, a sliding mode-based stabilizing state feedback controller is constructed on the basis of the finite-dimensional system. Subsequently, an infinite-dimensional Luenberger state observer, which utilizes a finite number of measurements, is constructed to provide estimates of the state of the infinite-dimensional system. Finally, an output feedback controller design is completed by coupling the infinite-dimensional Luenberger state observer and the sliding mode-based state feedback controller. Implementation, performance and robustness issues of the sliding-mode output feedback controller are illustrated in a simulation study of a distributed parameter system governed by the linearization around the spatially-uniform steady-state solution of the Kuramoto–Sivashinsky partial differential equation with periodic boundary conditions.     

表面碳化的硅纳米孔柱阵列的H2S室温电容传感特性

通过将硅纳米孔柱阵列(Si-NPA)进行高温碳化处理,制备出一种SiC/Si-NPA复合纳米体系。对SiC/Si-NPA的表面形貌和结构表征揭示,生长于Si-NPA上的SiC薄膜由具有立方结构的SiC纳米颗粒组成,厚度为～200 nm。SiC/Si-NPA整体上保持了Si-NPA原有的柱状阵列结构特征。对浓度介于0～1 200×10-6的H2S气体的室温传感性能测试表明,SiC/Si-NPA对H2S气体的电容响应灵敏度可高达790%,而其对400×10-6浓度H2S气体的响应和恢复时间则分别为170 s和200 s,元件具有较好的测量重复性和稳定性。SiC/Si-NPA可能是一种室温条件下较为理想的H2S气体传感材料。     

有机改性溶胶-凝胶传感膜检测亚硝酸根

以二甲基二乙氧基硅烷与四乙氧基硅烷为有机一无机复合前驱体,番红花红为敏感指示剂,利用溶胶-凝胶法研制出有机改性传感膜.实验结果表明:在酸性条件下传感膜与亚硝酸根作用,导致吸光度降低,且在一定范围内与亚硝酸根浓度呈良好的线性关系(R=0.9929),线性范围为0.001-0.1 mg·L-1,检出限为3×10-4mg·L...     

Landslide monitoring by ground-based radar interferometry: A field test in Valdarno (Italy)

A ground-based Interferometric Synthetic Aperture Radar (InSAR) was installed to monitor a landslide in Valdarno (Italy). The aim was to field-test an innovative remote sensing instrument able to provide distributed information over sliding slopes with a rate of several images a day. Radar images and interferometric displacement maps projected on the Digital Elevation Model (DEM) of the test site are reported.