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关键词： Radio frequency identification (RFID)  

摘要： Traceability of Manufacturing Equipment and Tools in the Production of High-performance X-ray Tubes. Modern technologies are a key enabler for the automatic identification of objects in production to ensure quality-related traceability of components or manufacturing equipment. This article presents a possible solution for the traceability of equipment, tools and measuring devices by applying a RFID system in the production of high-performance X-ray tubes and discusses the results of durability analysis. © 2022 Walter de Gruyter GmbH, Berlin/Boston, Germany.

关键词： AGV   RFID   室内定位   RSSI   定位算法  

摘要： 随着工业4.0的到来,传统的物流分拣系统已经被自动化、智能化的货物分拣系统取代,智能分拣系统不仅可以提高物流分拣效率,还可以降低人工成本,减轻工作量,缩短物流配送时间。AGV(Automated Guided Vehicle)车是智能分拣系统的重要组成部分,而智能导航方式是AGV车的核心技术。本文以AGV的导航方式为研究方向,以RFID通讯原理为基础,对基于RFID(Radio Frequency Identification)的AGV导航系统展开了研究。并通过理论推导以及实验验证,设计了一种基于RSSI测距模型的AGV导航方式,期望在控制成本的条件下,提高RFID的导航精度,从而满足智能物流的需求。本文主要工作内容如下:(1)在全面综述AGV导航方式和RFID研究现状的基础上,设计了一种基于RFID的AGV导航整体方案,分析了该方案的关键技术要求。(2)以基于RSSI信号传播模型为基础,提出了一种基于RSSI的双测距模型,利用MATLAB对信号接收的强度进行最小二乘法拟合,得到模型的参数,通过测距实验,结果显示:本文的双测距模型能提升测距的精度,同时可以减小阴影效应造成的影响。为避免由于电子标签的制造误差而造成测距精度的丢失,对每个标签都进行标定,使得每个电子标签均有符合自身的唯一的测距模型,实验结果表明:标定后的测距模型有着更为准确的精度。(3)通过分析比较基于测距的定位算法,在基于加权质心定位算法的基础上,提出了一种基于四节点的加权质心定位方式,实验结果表明:通过对加权值的优化,以及通过选择最佳的定位参考标签的方式,定位算法的精度得到了明显的提升。(4)搭建了AGV车定姿系统性能测试实验平台,实验表明:蜂窝型的标签排布方式更有利于定位精度的提升;本文采用的基于RFID的AGV导航系统最小的距离误差为0.32m最小角度误差为8.1°,能在一定范围内实时反映AGV车的位置及姿态信息,有效提高了基于RFID导航的导航精度。

关键词： RFID   近场   宽带   圆极化   反射面阵列天线  

摘要： 近场射频识别(Radio Frequency Identification,RFID)技术除具有快捷、高效等优点外,相较于远场RFID技术还具有读写范围可精准控制的优点,因而广泛应用于医疗、仓储、物流和零售等领域。其中各式各样的金属环境是近场RFID系统的重要应用场景。本文主要面向复杂金属环境中近场RFID读写器天线的覆盖问题,以及近场RFID系统在高度超过二分之一波长的半开放式金属货架中遇到的驻波问题展开研究,主要的研究内容和创新点如下:针对近场读写器天线读取面积小而不能覆盖较宽金属文件柜的问题,提出了一款读写区域可扩展的纯近场宽带读写器天线。天线基于平行微带线加载半环形耦合谐振器结构,通过增加谐振器数量实现读取区域可扩展。设计的1×4阵列天线工作频率为870-1600 MHz,100%标签读取范围为360×60×32 mm3。针对近场读写器天线读取距离近而不能覆盖较高金属货架的问题,提出了一款读写距离较远的近场宽带圆极化读写器天线。天线基于弯折偶极子结构实现低增益特性,通过顺序旋转90°相位馈电实现宽带圆极化性能。该天线工作频率为690-1160 MHz,读取范围为500×500×500 mm3,覆盖高度达到1.5倍波长。针对较高金属货架中电场分布的驻波现象导致RFID系统漏读的问题,提出了两款加载PIN二极管的1 bit可重构反射面阵列天线。反射面天线有两种不同的工作状态,对应的两种反射波相位存在180°相位差。反射面天线在金属货架中应用时,可以使空间中的电场波节点完全错开,两种工作状态相互弥补,从而抵消驻波现象造成的读取漏洞,保证近场RFID系统在600×800×680mm3的货架内部空间标签读取率达到100%,实现可靠读取。

关键词： Antenna   chipless tag   frequency-coded   RFID   multi-resonator   depolarization  

摘要： Chipless radio frequency identification (RFID) is a low-cost RFID solution that has the potential to replace traditional barcodes in short-range applications. In this paper, a novel frequency-coded chipless RFID tag is designed at Ku-band (12.4-18 GHz). Compared to previous designs, the proposed tag has a more compact design by multiplexing one tag antenna for both transmitting and receiving purposes. In addition, the tag is designed on a substrate with ground plane, which reduces the undesired effect of the background detuning. To demonstrate the performance of the proposed chipless RFID tag, four 3-bit tags are designed in simulation, with having two of them manufactured and tested. Simulations and measurements are performed for codes of 000 and 111, and the results verify the validity of the proposed design. Finally, the sensitivity of the tag response to fabrication errors and orientation are discussed and demonstrated with simulations.

关键词： RFID   neural network   Elman   YOLOv3   performance optimization  

摘要： As a non-contact automatic identification technology, Radio Frequency Identification (RFID) is of great significance to improve the simultaneous identification of multi-target. This paper designs a more efficient and accurate multi-tag reading performance measurement system based on the fusion of YOLOv3 and Elman neural network. In the machine vision subsystem, multi-tag images are collected by dual CCD and detected by neural network algorithm. The reading distance of 3D distributed multi-tag is measured by laser ranging to evaluate the reading performance of RFID system. Firstly, the multi-tag are detected by YOLOv3, which realizes the measurement of 3D coordinates, improves the prediction accuracy, enhances the recognition ability of small targets, and improves the accuracy of 3D coordinate detection. Secondly, the relationship between the 3D coordinates and the corresponding reading distance of RFID multi-tag are modelled by Elman recurrent neural network. Finally, the reading performance of RFID multi-tag is optimized Compared with the state-of-the-arts, the multi-tag detection rate of YOLOv3 is 17.4% higher and the time is 3.27 times higher than that of the previous template matching algorithm. In terms of reading performance, the MAPE of Elman neural network is 1.46 %, which is at least 21.43 % higher than other methods. In running time, Elman only needs 1.69s, which is at least 28.40% higher than others. Thus, the system not only improves the accuracy, but also improves the speed, which provides a new insight for the measurement and optimization of RFID performance.

关键词： Discrete cosine transforms   Phase measurement   Noise measurement   Feature extraction   Estimation   Location awareness   Adaptation models   Discrete cosine transform (DCT)   inventory management   machine learning   multipath   radio frequency identification (RFID)   synthetic aperture radar (SAR)  

摘要： Indoor radio frequency identification (RFID) tag positioning in strong multipath environments is critical in numerous industrial application scenarios, especially in production-related item monitoring. Among others, synthetic aperture radar (SAR)-based schemes have been developed, reconstructing tag positions from different angles. However, they usually compute entire holograms, containing lots of noncandidate grids and nonrelevant information to the tag position. This causes not only unnecessary overhead in position estimation, but also low generalization ability for a learning-based model. In this article, we propose a simple yet effective SAR-based tag localization model for fast and robust performance in strongly affected scenarios. In this model, we designed a two-step position estimation module based on a discrete cosine transform (DCT) for dimensionality reduction and an extra-trees model for position regression. Our model first preprocesses a mask to filter out noncandidate grids from holograms. This mask information is subsequently exploited in the regressor to further increase the positioning accuracy. Our experimental results showed that the proposed model surpasses existing holographic methods in both performance accuracy and inference time and can achieve 2 cm mean lateral accuracy in a strongly affected scenarios, with about a minute over training and testing phases.

关键词： Strain   Radiofrequency identification   Sensors   Patch antennas   Capacitive sensors   Antenna measurements   Wireless communication   Direction detection   magnitude detection   radio frequency identification (RFID) antenna   resonant frequency shift (RFS)   sensor array   strain sensing  

摘要： Radio frequency identification (RFID) antenna sensors have become one of the most interesting areas of passive strain sensing owing to the advantages of battery-less and wireless interrogation. However, existing RFID methods could mainly detect strain magnitude with its direction along the length or width of the radiant element. To meet the practical purpose of strain detection, a magnitude and direction detection method based on an RFID sensor array is proposed. First, a single strain sensor, i.e., a short stub feed patch antenna, is designed. Specifically, taking resonant frequency shift (RFS) as the feature of strain amplitude, the sensor has different sensitivities in the electrical length direction and width direction. Then, based on this characteristic, a sensor array consisting of four sensors with a mutual angle of 45 & x00B0;is proposed to achieve the quantitative detection of strain magnitude and direction. Finally, the feasibility of the proposed method is validated by simulations and experiments. Experimental results show that the sensitivities of the single strain sensor in the longitude direction and transverse direction are & x2212;873.91 and 57.28 Hz/, respectively. The strain magnitude detection accuracy of the proposed sensor array is within 10 & x0025;except for individual abnormal values, and the direction detection error of the sensor array is within 3 & x00B0;.

关键词： 智能门锁   BLE通信   NB-IoT通信   RFID技术   二代身份证   低功耗模式  

摘要： 随着居民生活水平的提高和嵌入式技术的不断发展,智能门锁因其便捷、安全和高效渐渐走入了大众的生活。在酒店公寓管理这种人员流动较为频繁的应用场景,以生物特征认证的方式因具有泄露隐私的风险,显然是不太适宜的。又因酒店公寓管理本身就需要身份登记,而二代身份证所采用的加密技术也远高于酒店自制IC卡,选择使用身份证作为识别方式显然是一种便捷的认证方式。当今生活智能手机已变成出门携带的必备之物,因此通过手机APP解锁也是一种便捷的解锁方式。同时作为酒店公寓这种拥有大量房间的地方,仅仅让单个门锁闭环工作是不够的,门锁管理者需要知道每一个设备的运行状况,因此就有了设备联网的需求。物联网技术因其广范围、低功耗的特点使得门锁的运行信息在低功耗状态下上传网络成为了可能。在对系统需求分析的基础上,本文设计并实现了一套基于BLE和NB-IoT技术的身份证门锁系统。该门锁系统既可以使用基于ISO14443B标准的二代身份证刷卡识别,也可以使用BLE蓝牙技术解锁。为实现解锁功能,本文选择了具有蓝牙射频功能的国产芯片SYD8811作为主控芯片。手机APP端通过BLE向门锁终端发出解锁指令,验证成功后就可以解锁。在RFID识别方面,本文设计了射频识别模块,该模块支持Tybe B型卡片的识别,可用来验证身份ID解锁。为防止身份数据泄露,本文融合SHA1加密算法和AES128加密算法实现了将身份证数据加密为密文来解锁的功能。除了实现门锁的基本功能外,本系统还实现了设备信息、用户数据、电量数据和开锁记录的上传。上传的方式有两种:一种是基于BLE的近距离APP端上传,在BLE的数据上传中设计了数据压缩算法,实现了数据高效准确传递。另一种是基于NB-IoT物联网模块远距离云端定时上传。两种上传方式使门锁的信息能被门锁管理者及时获取。本文的门锁需要在四节干电池的供电下保持长达数月的使用,基于门锁功耗考虑,本文为门锁系统设计了低功耗控制电路,并根据各个芯片的特性设计运行机制,使得系统功耗大大降低,最终设计的系统可以在4节干电池下使用达5个月以上。在硬件方面,本文完成了门锁终端硬件电路的理论设计和原理图的绘制,并根据原理图绘制了与之相适应的PCB板,最后经过投板焊接电路完成了终端电子模组的制作。在软件方面,本文设计了门锁终端与APP端的蓝牙通信,NB-IoT物联网模块与门锁终端的通信,RFID模块的识别流程,解锁过程中产生密文的加密算法的设计,门锁相关数据的存储方法,门锁终端各外围功能的程序等进行了设计。最后对系统整体进行了各项性能的测试,测试结果表明系统响应速度和各项功能的实现等指标均符合设计预期。

关键词： RFID   丢失标签识别   Bloom过滤器   已知标签  

摘要： 射频识别(RFID)技术是物联网的一种核心技术,被广泛应用于物流管理、仓库管理和物品定位等多个领域。在仓库管理中,利用RFID技术替代原有的条形码来管理货物,每年可以节约大量金额的成本和人力开销。在实际应用场景中,商品会由于偷窃、管理不善等问题造成丢失,这无疑会给商家带来巨大的经济损失,所以就需要使用丢失标签识别协议来识别具体丢失了哪些商品。通过丢失标签识别协议可以快速地识别出有哪些标签发生了丢失,以便于商家能够及时地采取补救措施。 RFID系统内的未知标签会对丢失标签识别的精度产生影响,而目前存在的大部分丢失标签识别协议没有考虑RFID系统内存在未知标签的情况。为了减少未知标签对丢失标签识别的影响,提高丢失标签识别的精度,本文提出了基于分类的丢失标签识别协议(MIBC)。MIBC可以在含有未知标签的RFID系统当中完成对丢失标签的识别,MIBC含有过滤阶段、分类阶段和丢失标签识别阶段三个阶段。过滤阶段是利用Bloom过滤器过滤掉未知标签,从而防止未知标签干扰对丢失标签的识别,并将被过滤掉的未知标签停用。分类阶段中阅读器随机地把系统中已知标签分类。每一类标签将在丢失标签识别阶段的同一个轮次中响应阅读器。丢失标签识别阶段将分为多轮执行,在每一轮的执行中停用未知标签、识别丢失标签并且确认系统内存在的已知标签。进一步,我们以Bloom过滤器的停用率为目标函数来优化过滤阶段中的哈希函数数量k和Bloom向量的长度B,并近似估计了每个阶段的执行轮数,又确定了丢失标签识别阶段的帧长以及分类阶段的分类数量。 为了评估MIBC的性能,本文将执行时间和实际可靠性作为评价指标进行试验,并与现有的丢失标签识别协议进行对比。实验结果表明,MIBC在可靠性相当的情况下,所需的时间成本上要低于其它协议。

关键词： Sensors   Antenna measurements   Antennas   Radiofrequency identification   Radio frequency   Ice   Resonators   Antennas   antenna gain   antenna sensors   ice sensing   impedance matching   RF ice sensing   RFID   materials   relative permittivity measurement   wireless sensing  

摘要： Remote ice detection has emerged as an application of Radio Frequency (RF) sensors. While antenna-based "RFID" sensing can detect various measurands, antenna-based sensors are not currently designed based on a systematic methodology, and in most cases may have a low sensitivity requiring specialist hardware or broadband interrogation signals, incompatible with spectrum regulations. Here, we develop a systematic methodology for designing an antenna-based sensor, applicable to measurands inducing a dielectric change in the near-field of the antenna. The proposed methodology is applied to designing printable antennas as highly-sensitive sensors for detecting and measuring the thickness of ice, demonstrating best-in-class sensory response compared to more complex antenna designs. Antenna design is investigated systematically for wireless interrogation in the 2.4 GHz band, where it is found that a loop antenna outperforms a dipole owing to its more distributed capacitance. The antenna's realized gain was identified as the optimum parameter-under-test, with "positive" sensing proposed as a method of improving linearity and immunity to interference. The developed loop antenna sensor exhibits resilience to interference and applicability to different real-world deployment environments, demonstrated through over 80% average ice thickness measurement accuracy and at least 5 dB real-time sensitivity to ice deposition.