基于声电原理触滑觉传感器的研究

滑觉检测是机器人实现软抓取的关键环节,首次提出了一种低成本的基于电声原理的小型滑觉传感器并进行了性能试验研究.该传感器主要由麦克风和一个密封腔组成,结构简单,成本低.通过把物体滑动时造成的微小震动信号转化为声电信号,利用小波分析处理采集到的信号.性能试验表明,该传感器能够提供可靠的触滑动信号.     

3D Surface Reconstruction of Noisy Point Clouds Using Growing Neural Gas: 3D Object/Scene Reconstruction

With the advent of low-cost 3D sensors and 3D printers, scene and object 3D surface reconstruction has become an important research topic in the last years. In this work, we propose an automatic (unsupervised) method for 3D surface reconstruction from raw unorganized point clouds acquired using low-cost 3D sensors. We have modified the growing neural gas network, which is a suitable model because of its flexibility, rapid adaptation and excellent quality of representation, to perform 3D surface reconstruction of different real-world objects and scenes. Some improvements have been made on the original algorithm considering colour and surface normal information of input data during the learning stage and creating complete triangular meshes instead of basic wire-frame representations. The proposed method is able to successfully create 3D faces online, whereas existing 3D reconstruction methods based on self-organizing maps required post-processing steps to close gaps and holes produced during the 3D reconstruction process. A set of quantitative and qualitative experiments were carried out to validate the proposed method. The method has been implemented and tested on real data, and has been found to be effective at reconstructing noisy point clouds obtained using low-cost 3D sensors.     

Pd掺杂对SnO_2气敏性能的影响

在气体传感器中金属Pd被广泛用作的催化剂,利用直流溅射和浆料涂覆的方法制备出SnO2气敏元件,在氧气氛中通过直流溅射对SnO2元件进行Pd掺杂,并对用不同制备方法所得元件的电导、灵敏度等进行比较。结果表明:Pd掺杂降低了元件的电导,并使得电导峰出现的位置从460℃转移到260℃和180℃,这和样品的制备方法有关。Pd掺杂有利于提高SnO2元件的灵敏度,特别在低温区(100~250℃)对不同气体的灵敏度有几十倍提高。     

Optimization of a wafer-level process for the fabrication of highly reproducible thin-film MOX sensors

Thin-film metal oxide semiconductor (MOX) gas sensors are characterized by high sensitivity and fast response. Those characteristics make them very promising among the several existing technologies for the production of solid state gas sensors. Furthermore, by means of silicon micro-machining technology, MOX sensors can be made on micro hotplates, allowing to reach very low-power consumption, and the batch production guaranties a high yield. However, reproducibility and reliability are still major issues preventing the use of thin-film MOX sensors in mass-market applications.

In this work, a wafer-level fabrication process for micro-machined low-power consumption thin-film MOX sensor arrays is reported. Different solutions for the optimization of the fabrication process are investigated, aiming to increase the reproducibility. The critical technological steps related to signal generation and acquisition, like the thin-film definition and positioning and the definition of the sensing layer electrodes, have been optimized. The devices considered are 4-sensor arrays based on thin films of SnO₂ deposited by a modified rheotaxial growth and thermal oxidation (M-RGTO) technique on micro-machined low-power hotplates.

The different fabrication techniques are described in detail. 45 sensors from 3 wafers, made using the different fabrication techniques, are comparatively characterized. The spread of the main sensor functional parameters values shows an evident decrease when the optimized fabrication process is used.     

异源、同源传感器影像融合的比较研究

遥感影像的融合是遥感界的一个研究热点。根据数据源的不同,影像融合可分为异源传感器影像融合和同源传感器影像融合。以TM与SPOT作为异源影像融合的例子,以IKONOS的MS与Pan作为同源影像融合的例子,用5种算法对两种融合类型进行实验与比较。结果表明,同源传感器影像的融合效果好于异源传感器影像的融合效果;不同的融合算法在异源和同源传感器影像融合中的表现不尽相同。SVR变换可同时应用于异源及同源传感器影像的融合,且在提高影像空间分辨率、信息量和清晰度的同时能很好地保持原始多光谱影像的光谱特征。SFIM虽然也可以在两种数据源的融合实验中获得较好的融合效果,但其高频信息融入度最差。MB虽然提高了融合影像的高频信息融入程度,但光谱保真度、信息量和清晰度却不理想。Ehlers适用于异源传感器影像间的融合,而WT则适用于同源传感器影像的融合。     

基于SAW表面气液相效应和GC分离柱的气敏传感器

限于传统涂敷敏感膜的声表面波（SAW）气敏传感器存在成膜困难和选择性差、重复性差以及再生性差等问题,本研究提出一种基于压电基底表面气体气液相转换效应机理的瑞利波传感器。在此基础上开发了一种基于瑞利声表面波传感器和气相色谱（GC）分离柱的便携式气体检测系统。最后实验论证了方案的可行性,初步的实验结果表明该系统具有分析时间短、选择性好、灵敏度高,可检测ppb（10^-9）浓度的混合VOCs以及成本低等优势,显示其在痕量挥发性有机气体检测和分析应用上有良好的潜力和前景。     

用于室内有毒气体快速检测的便携式CC/SAW电子鼻

开发了一种用于室内空气质量快速检测的便携式电子鼻气体分析仪.该仪器利用毛细管分离柱(CC)将混合气体选择性分离,实现对气体的分类识别,然后借助声表面波(SAW)传感器频率响应测量每种组分对应的浓度,实现对气体的量化.实验针对17种有毒有害气体进行测试,结果表明该系统能对低浓度复杂混合气体进行快速检测,且具有较高的灵敏度,良好的选择性和重复性.这为不同应用场合下的痕量气体检测提供了一种可行的技术.     

热催化气体传感器的特性分析及其设计原则

热催化气体传感器的输出受诸多因素的影响,从理论上分析其输出特性有助于传感器的优化设计和性能评估。从一个热催化气体传感器的典型结构和热催化气体敏感机理出发,应用热平衡方程和热敏电阻的电阻温度关系推导了传感器输出与被测气体浓度、催化反应速度、工作温度以及传感器结构尺寸等之间的定量关系。从推导过程中的诸多假设,得出了热催化气体传感器设计时应遵循的一般原则。     

气体传感器阵列温度漂移抑制的研究

半导体气体传感器存在漂移问题,温度变化对漂移的影响尤为明显.在气体传感器阵列中,可以加入温度、湿度等传感器,监测其工作环境.实验系统采用恒温箱设定一组温度,制备气体样本20例(两种浓度样本各10例),采集传感器对样本的响应;通过人工神经网络来识别样本;当有误判发生时,在原网络中引入温度传感器的响应值,消除了误判,在一定程度上抑制了漂移,改善了网络性能,验证了该温度漂移抑制方法的可行性.     

面向目标侦测的非配合式无线传感器网络研究

针对战场目标侦测需求,在满足无线传感器网络低成本、低功耗约束条件的前提下,选择了传感器组合,设计实现了非配合式无线传感器网络硬件平台,采用红外传感器作为"唤醒传感器"实现节点休眠唤醒功能,同时检测人员与车辆,磁阻传感器负责铁磁物质检测,声音传感器实现车辆与人员的声音信号特征检测,利用简单实用的数据处理方法对各传感器信号...     

Humidity sensor based on LiCl-doped ZnO electrospun nanofibers

The humidity sensitive characteristics of sensors fabricated from pure ZnO nanofibers and LiCl-doped ZnO composite fibers by screen-printing on ceramic substrates with carbon interdigital electrodes have been investigated. The best result is obtained for 1.2 wt% LiCl-doped sample, which exhibits high humidity sensitivity, rapid response and recovery, small hysteresis, excellent linearity, and good reproducibility. The impedance of the sensor varies more than four orders of magnitude during the whole relative humidity (RH) from 11 to 95%. The response time and recovery time of the sensor is about 3 and 6 s, respectively. These results make our product a good candidate in fabricating high performance humidity sensors.     

Integrated On-Line Localization,Mapping and Coverage Algorithm of Unknown Environments for Robotic Vacuum Cleaners Based on Minimal Sensing

This paper presents a new complete coverage algorithm of a robotic vacuum cleaner (RVC) with a low-cost sensor in an unknown environment. To achieve complete coverage, the RVC must have navigation systems for precise position estimation with localization and a prior map or a map using information that has been continuously collected from the environment. To do this, two-dimensional laser range finders and vision sensors are becoming increasingly popular in mobile robotics, and various methods using sensors like these have been introduced by many researchers. However, it is difficult to apply the methods to sensors used in most RVCs due to their constraints. In this paper, we present a new method applied to most RVCs. For developing the method, we considered the two main problems of maintaining low computational load, and coping with low-cost sensor systems with limited range, detection uncertainty and measurement error. To solve the problems, we propose an assumption that major structures of an indoor environment are rectilinear, and can be represented by sets of parallel and perpendicular lines. Then we derive an algorithm that uses this assumption to map the environment, localize the robot and plan the coverage path with a new cellular decomposition approach. Simulation and experiments verify that the proposed method guarantees complete coverage.     

High-precision low-power quartz tuning fork temperature sensor with optimized resonance excitation

This paper presents the design, fabrication, and characterization of a quartz tuning fork temperature sensor based on a new ZY-cut quartz crystal bulk acoustic wave resonator vibrating in a flexural mode. Design and performance analysis of the quartz tuning fork temperature sensor were conducted and the thermal sensing characteristics were examined by measuring the resonance frequency shift of this sensor caused by an external temperature. Finite element method is used to analyze the vibratory modes and optimize the structure of the sensor. The sensor prototype was successfully fabricated and calibrated in operation from 0 to 100 °C with the thermo-sensitivity of 70×10^?6/°C. Experimental results show that the sensor has high thermo-sensitivity, good stability, and good reproducibility. This work presents a high-precision low-power temperature sensor using the comprehensive thermal characterization of the ZY-cut quartz tuning fork resonator.     

Soft analyzers for a sulfur recovery unit

This work deals with the design and implementation of soft sensors for a Sulfur Recovery Unit (SRU) in a refinery. Soft sensors are mathematical models able to emulate the behavior of existing sensors on the basis of available measurements. In this application, they are used when sensors are taken off for maintenance. The measurements considered in this work are very important for the environmental impact of the refinery, as they regard pollutant acid gas emissions. Four strategies have been implemented and compared: Multi-Layer Perceptrons (MLP) and Radial Basis Function neural networks, Neuro-Fuzzy networks and nonlinear Least-Squares (LSQ) fitting. The best performance is given by MLP neural networks and nonlinear LSQ, all of them implementing Nonlinear Moving Average models. The best soft sensors have been installed on the on-line distributed control systems of the refinery and on-line performance is highly satisfactory.     

Development of a resistive compact slip sensor using dielectric elastomer

Tactile sensor for detecting slip is essential to safely grasp an object for a robot hand with a complicated structure and various functions. In this paper, sensors with three patterns in different forms are designed to sense slip moment through a resistance change. The slip sensors of novel design have flexible and stretchable to be used on the robot hand surface. For realizing these characteristics, acrylonitrile-butadiene rubber (NBR) is used as a substrate of the sensor. Graphene material is employed because of suitability for flexible substrate as an electrode. An imprint process to produce a micro-unit structure to sensor surface is newly developed. As a result, sensors have an extremely small structure that can operate suggested working principle perfectly. Parameters of the micro structure is confirmed by FEM simulation earlier. Experiments for performance of the developed sensors are conducted. Through results of experiments, the pattern that has the best performance to know slip moment was checked.

     

A flexible encapsulated MEMS pressure sensor system for biomechanical applications

 The use of pressure sensors made of conductive polymers is common in biomechanical applications. Unfortunately, hysteresis, nonlinearity, non-repeatability and creep have a significant effect on the pressure readings when such conductive polymers are used. The objective of this paper is to explore the potential of a new flexible encapsulated micro electromechanical system (MEMS) pressure sensor system as an alternative for human interface pressure measurement. A prototype has been designed, fabricated, and characterized. Testing has shown that the proposed packaging approach shows very little degradation in the performance characteristics of the original MEMS pressure sensor. The much-needed characteristics of repeatability, linearity, low hysteresis, temperature independency are preserved. Thus the flexible encapsulated MEMS pressure sensor system is very promising and shows superiority over the commercially available conductive polymer film sensors for pressure measurement in biomechanical applications. Received: 1 December 1999/Accepted: 17 August 2000     

Combining Intelligent Techniques for Sensor Fusion

Mobile robots rely on sensor data to build a representation of their environment. However, sensors usually provide incomplete, inconsistent or inaccurate information. Sensor fusion has been successfully employed to enhance the accuracy of sensor measures. This work proposes and investigates the use of Artificial Intelligence techniques for sensor fusion. Its main goal is to improve the accuracy and reliability of the distance measure between a robot and an object in its work environment, based on measures obtained from different sensors. Several Machine Learning algorithms are investigated to fuse the sensors data. The best model generated by each algorithm is called estimator. It is shown that the employment of estimators based on Artificial Intelligence can improve significantly the performance achieved by each sensor alone. The Machine Learning algorithms employed have different characteristics, causing the estimators to have different behaviors in different situations. Aiming to achieve an even more accurate and reliable behavior, the estimators are combined in committees. The results obtained suggest that this combination can further improve the reliability and accuracy of the distances measured by the individual sensors and estimators used for sensor fusion.     

Performance of glucose biosensor based on oxygen electrode in physiological fluids and at body temperature

A potentially implantable glucose biosensor for continuous monitoring of glucose levels in diabetic patients has been developed. The glucose biosensor is based on an amperometric oxygen electrode and glucose oxidase immobilized on carbon powder held in the form of a liquid suspension. The enzyme material can be replaced (the sensor recharged) without sensor disassembly. Diffusion membranes made of silastic coatings over a microporous polycarbonate membrane are used. Calibration curves of the sensors in phosphate buffer solution and in undiluted blood plasma at body temperature have been obtained. The reproducibility of the sensor response in serum at body temperature is demonstrated. The sensors have a stable signal during storage and continuous operation at body temperature for a period of at least one month.     

基于SAW表面气液相效应和GC分离柱的气敏传感器的研究

限于传统涂敷敏感膜的声表面波（SAW）气敏传感器存在成膜困难和选择性差、重复性差以及再生性差等问题，本研究提出一种基于压电基底表面气体气液相转换效应机理的瑞利波传感器。首先建立了挥发性有机气体(VOCs)液相凝聚体薄层负载下的SAW波传模型，并仿真计算了其波传频散和波传衰减。然后在此基础上开发了一种基于瑞利声表面波传感器和气相色谱（GC）分离柱的便携式气体检测系统。最后实验论证了方案的可行性，初步的实验结果表明该系统具有分析时间短、选择性好、灵敏度高（可检测ppb浓度的混合VOCs）以及成本低等优势，因此其在痕量挥发性有机气体检测和分析应用上有良好的潜力和前景。     

光纤传感技术在物联网中的应用

现如今,物联网已经发展成为了一个研究热点,而光纤传感技术在物联网的发展中也得到了广泛的应用,并引起了广泛的关注。物联网的核心部件为传感器,特别是光纤传感器,它和其它的类型的传感器所不具有的优势,而物联网主要有四个技术构层,它们是应用接口、数据处理技术、数据传输网络和传输网络,在物联网中我们将会看到有大量的各种各样的传感器的存在,这些传感器可以用来感知不同的环境参数,比如温度、重力、光电、声音、震动和位移,这些传感器为物联网提供最原始的数据信息。当前,光纤传感技术在物联网中的应用引起社会各界的高度关注。本文主要对物联网的界定、构成以及光纤传感器的原理和发展现状进行了深入的探讨和分析,并且重点是对光纤传感技术在物联网中的应用加以详细阐述。希望可以通过本文的论述,能够对今后光纤传感技术在物联网中的应用产生一些积极影响。