Global Calibration Based on Local Calibration for an Ultrasonic Location Sensor

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基于自然地表的星载光子计数激光雷达在轨标定

第49卷第11期V ol.49N o.ll红外与激光工程Infrared and Laser Engineering2020年11月Nov. 2020基于自然地表的星载光子计数激光雷达在轨标定赵朴凡，马跃，伍煜，余诗哲，李松(武汉大学电子信息学院，湖北武汉430072)摘要：在轨标定技术是影响星载激光雷达光斑定位精度的核心技术之一。

介绍了目前国内外星载激光雷达的在轨标定技术发展现状，分析了各类在轨标定技术的特点。

针对新型的光子计数模式星载激光雷达的特性，提出了一种基于自然地表的星载光子计数激光雷达在轨标定新方法，使用仿真点云对标定算法的正确性进行了验证，并分别使用南极麦克莫多干谷和中国连云港地区的地表数据和美国ICESat-2卫星数据进行了交叉验证实验，实验结果表明：算法标定后的点云相对美国国家航空航天局提供的官方点云坐标平面偏移在3 m左右，高程偏移在厘米量级。

文中还利用地面人工建筑等特征点对比了算法标定后的点云与官方点云之间的差异，最后对基于自然地表的在轨标定方法的精度以及标定场地形的影响进行了讨论。

关键词：光子计数激光雷达；自然地表；在轨标定；卫星激光测高中图分类号：TN958.98 文献标志码：A DOI：10.3788/IRLA20200214Spaceborne photon-counting LiDAR on-orbitcalibration based on natural surfaceZhao Pufan，Ma Yue，Wu Yu，Yu Shizhe，Li Song(School of Electronic Information, Wuhan University, Wuhan 430072, China)Abstract:On-orbit calibration technique is a key factor which affects the photon geolocation accuracy of spaceborne LiDAR. The current status of spaceborne LiDAR on-orbit calibration technique was introduced, and the characteristics of various spaceborne LiDAR on-orbit calibration technique were analyzed. Aiming at the characteristics of the photon counting mode spaceborne LiDAR, a new on-orbit calibration method based on the natural surface was derived, simulated point cloud was used to verify the correctness of the calibration algorithm, and a cross validation experiment was made with the surface data of the Antarctic McMudro Dry Valleys and China Lianyungang areas and ICESat-2 point cloud data, the experimental results show that the plane offset between the point cloud calibrated by proposed algorithm and point cloud provided by National Aeronautics and Space Administration is about 3 m, elevation offset is in centimeter scale. The differences between the point cloud calibrated by the algorithm and the point cloud provided by National Aeronautics and Space Administration were also compared by using the feature points of artificial construction on the ground. Finally, the accuracy of the on- orbit calibration method based on natural surface and the influence of the calibration field topography were discussed.Key words:photon-counting LiDAR; natural surface; on-orbit calibration; spaceborne laser altimetry收稿日期:2020-05-28;修订日期:2020-06-29基金项目:国家自然科学基金(41801261);对地高分国家科技重大专项（11-Y20A12-9001-17/18,42-Y20A11-9001-17/18);中国博士后科学基金(2016M600612, 20170034)作者简介:赵朴凡（1996-)，男，博士生，主要从事激光标定理论与方法方面的研究工作：Email:****************.cn导师简介:李松（1965-)，女，教授，博士生导师，博士，主要从事卫星激光遥感技术与设备方面的研究工作Email:**********.cn20200214-1第11期红外与激光工程第49卷0引言星载激光雷达是一种主动式的激光测量设备，它根据激光脉冲的渡越时间（Time of Flight,ToF)获得卫星与地表目标间的精确距离值，结合卫星平台的精确姿态、位置信息以及激光指向信息后可以获得目标的精确三维坐标。

指南：通过校准提高总设备效果（OEE）说明书

Guide to improvingOverall EquipmentEffectiveness (OEE)through calibrationApplication NoteCalibration is an indispensable tool for makingmeasureable improvements in process perfor-mance. An effective calibration program helpsreduce significant wastes of time spent on:•U nplanned maintenance•S crapped product•R eworkMeasuring the impact of these wastes on pro-cess performance is facilitated using OEE (OverallEquipment Effectiveness).OEE is a “best practice” metric for evaluating the efficiency of a manufacturing process. It is often a key performance indicator in an organiza-tion implementing a lean production system. OEE identifies the most common sources of manufac-turing productivity losses and places them into one of three groups:•A vailability•P erformance•Q ualityOEE is calculated from the formulaTo maximize efficiency, the OEE value should ideally be as close to 100% as possible. Actual values range from 0% to 100%, with a bench-mark value typically around 85% that varies by industry.AvailabilityA plant represents a considerable investment, and stakeholders expect it to be managed effectively and efficiently. The amount of time equipment is available for operation is the Planned Production Time. It includes scheduled maintenance and other factors that might lead to a planned shutdown. For example, most plants schedule downtime for regular maintenance, including cali-bration of sensors and instrumentation. Planned maintenance reduces the impact of a shutdown on a business. However, even with good plan-ning, Planned Production Time can be lost when downtime occurs unexpectedly. The time left after subtracting unplanned downtime from Planned Production Time is the remaining Operating Time. The ratio of Operating Time to Planned Production Time is the OEE metric of Availability.One of the reasons for lost production time is unplanned maintenance. This can occur whena sensor or transmitter drifts out of specifica-tion during a production run. The problem may be detected by a Supervisory Control and Data Acquisition (SCADA) system alarm or further down the line after considerable troubleshooting, whenquality defects are observed during inspection.OEE = (Availability)×(Performance)×(Quality)Critical instruments require special attentionIn a process facility, instruments are used to moni-tor and control processes, and some instruments are more important than others. In many casesa high degree of confidence in an instrument’s performance is required: for example, consider those instruments that have a direct impact on product quality and throughput, or those that help ensure the safety of personnel, customers, the community or the environment. In addition, cer-tain instruments or systems may be critical during emergency response activities. In a well-managed facility, regular maintenance at predetermined intervals ensures these instruments continually conform to their specifications, so that costly or even disastrous surprises are avoided. Calibration intervals need to be monitoredTo avoid unplanned downtime and other surprises, calibrations should occur at regularly scheduled intervals. Calibration verifies the functionality of the instrument and can reset the drift that all mea-surement equipment experiences over time. Longer intervals between calibrations are desir-able to help maximize equipment operating time. However, if an instrument is found out of tolerance at the time of calibration, the calibration interval is usually reduced (for example, a policy may require that the instrument be calibrated twice as often when found out of tolerance to mitigate the risk of future recalls due to an out-of-tolerance condition).To ensure that the period between calibra-tions is as long as possible, while also ensuringthat instruments remain in tolerance between calibrations, wise managers make certain that the equipment used to calibrate their instruments isthe best that they can get. They know that a moreaccurate calibration maximizes Operating Time.Up-timeLower quality calibrationHigher quality calibrationIncreased up-timeAccuracy improvementMaximum allowable errorOut of toleranceFigure 1. Sensors andtransmitters that driftout of specificationduring a production runcan cause unplanneddowntime, safetyissues, and losses inproduct quality.Figure 2. Minimizing error maximizes up-time. Measuring instrument error tends to increase (drift) over time. This error is corrected through calibration. Less error in the calibration means fewer surprises and a longer period of time before the next calibration is required.PerformanceWhen a process is operating, it may run slower than planned. For example, some operators may not be efficient, accidents may happen, or the equipment may be worn or poorly maintained. These factors combine to slow the process down and contribute to a reduced Net Operating Time. The ratio of Net Operating Time to Operating Time is the OEE metric of Performance.The key to maximizing performance is to reduce the many short stops that make less efficient use of Operating Time.Net Operating Time is usually calculated this way: Or equivalentlyIdeal Cycle Time is the ideal amount of time it should take to produce one unit such as a piece or a volume of product. Calculating Net Operating Time this way ensures the amount produced is measured and not just how much time was spent producing.QualityQuality takes into account the products which do not meet quality standards, including pieces that might require rework. Time spent reworking or pro-ducing a rejected product is lost time. Time left after quality-related losses is the Fully Productive Time.Quality is affected when critical measurements are made by instruments that are operating outside of their designed specifications. Calibration helps to keep critical process variables within the param-eters required by the process. When calibrations are not performed properly, occur too infrequently, or if calibration standards lack the required accu-racy, then quality may be impacted. When quality problems are detected an unplanned shutdown may follow, which has an impact on Availability and further reduces OEE.ExampleHere is how we might calculate OEE for a hypo-thetical shift with the following data:AvailabilityTo calculate the Availability we need to know the Planned Production Time and the Operating Time.Operating timePerformanceThe calculation of Performance is based on a standard production cycle time, the number of units produced and the operating time calculated above.Net Operating Time = (Total Units Produced)×(Ideal Cycle Time)QualityThe Quality calculation is the ratio of Fully Pro-ductive Time to Net Operating Time, but you get the same answer if you take the ratio of GoodOEE (Overall Equipment Effectiveness) is calcu-lated by taking the product of the three metrics calculated above:Improving OEEIf the process is not as effective as it should be, then what can be done to make it more effec-tive? For example, if the benchmark metric of 85% mentioned in the beginning is achieved, then the metrics of Availability, Performance, and Quality will each probably be in the mid 90’s. The above example includes room for improvement in each of the metrics. Here are some things to consider to improve OEE through calibration:1. Schedule maintenance at a time when it will be least disruptive and ensure that calibration is part of the maintenance program, especially for critical instruments.2. Follow best practices when calibrating and use the best calibration equipment available to prevent unscheduled troubleshooting and cali-bration due to nonconforming instrumentation.3. Reduce planned downtime by carefully manag-ing calibration intervals. This can be achieved by using high-quality instruments, monitoring their performance, and following best practices to maintain them.4. Strive to maintain a 4:1 test accuracy ratio (TAR) to minimize the risk of incorrectly evaluating the tolerance status of the instru-ments being calibrated. A 4:1 TAR means that the accuracy of the calibration standard is four times better than the accuracy of the instru-ment it is calibrating. Incorrectly identifying a nonconforming instrument as “in tolerance” may lead to quality and other potential prob-lems. Incorrectly identifying the instrument as “out of tolerance” leads to increased downtime, more maintenance costs, and shorter calibra-tion intervals.5. Automate calibration with software to minimize operator time, ensure best practices and speed up the process. In some cases automation can be achieved without software. For example: a) A Fluke Calibration 1586A Super-DAQ Preci-sion Temperature Scanner can automate anddocument a temperature calibration involv-ing a bath, dry-well, or furnace.Fluke Calibration 1586A Super-DAQ Precision Temperature Scanner automates the calibration of thermocouples in a Fluke Calibration 9190A Ultra-Cool Field Metrology Well.OEE = (Availability)×(Performance)×(Quality)= 85.7 % × 83.3 % × 88.0 % = 62.8 %Fluke Calibration PO Box 9090,Everett, WA 98206 U.S.A.Fluke Europe B.V.PO Box 1186, 5602 BD Eindhoven, The NetherlandsFor more information call:In the U.S.A. (877) 355-3225 or Fax (425) 446-5116In Europe/M-East/Africa +31 (0) 40 2675 200 or Fax +31 (0) 40 2675 222 In Canada (800)-36-Fluke or Fax (905) 890-6866From other countries +1 (425) 446-5500 or Fax +1 (425) 446-5116 Web access: ©2015 Fluke Calibration. Specifications subject to change without notice. Printed in U.S.A. 12/2015 6006652a-enModification of this document is not permitted without written permission from Fluke Calibration.Fluke Calibration. Precision, performance, confidence.™b) A Fluke 754 Documenting Process Calibra-tor connected to a Fluke dry-well using the Hart Drywell Cable automates anddocuments the calibration of a temperature sensor and transmitter. DPC/Track software is required with the 754 to download the information to a PC and manage calibra-tion data.6. Reduce planned downtime by carefully manag-ing calibration intervals. This can be achieved by using high-quality instruments, monitoring their performance, and following best practices to maintain them.7. Reduce rework during production with a prop-erly tuned control system that produces product conforming to its design specifications.ConclusionCalibration is an important part of improving the Overall Equipment Effectiveness of processes that use instrumentation to control the quality of both the process and product. An effective calibration program will help reduce three significant wastes of time spent on:•unplanned maintenance •s crap •r eworkSuch a calibration program will use the best calibration equipment available, and follow best calibration practices including automation where possible. This will ensure that critical measure-ment equipment is not the cause of an unplanned shutdown or quality issue.Fluke 754 Documenting Process Calibrator calibrating a temperature sensor and transmitter with the help of a Fluke Calibration 9142 Field Metrology Well.。

兰州大学《卫星气象学》第4章-美国气象卫星观测系统-3-CALIPSO+Cloudsat

《卫星气象学》电子课件（第一版）
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CALIPSO卫星直观图
《卫星气象学》电子课件（第一版）
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WFC
宽视角相机（ WFC ）是 CT-633 星跟踪器相机的改进装置，是一固定的天底单通道成像仪，采用单一谱段，波长范围 270-620nm ，主要目的是为了和 Aqua 卫星中的中分辨率成像光谱仪的一个谱段进行匹配。主要技术指标为：红外视场125m，行宽61km，数据传输率26kb S-1。
相对于全球观测，地基、车载以及机载激光雷达等观测范围都有限，只能
在较小的区域内进行观测。而星载激光雷达则可以实现全球观测，尤其在海洋、南北极、沙漠等传统激光雷达难以观测的地区。
《卫星气象学》电子课件（第一版）
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激光雷达
L2S-SM II
MPL -4B
《卫星气象学》电子课件（第一版）
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CALIPSO卫星白天和晚上的轨道
Volcanic aerosol
Cirrus
Water
《卫星气象学》电子课件（第一版）
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激光雷达Level1 退偏比及颜色比廓线
退偏比：衡量粒子的非球形，值越大，粒子越趋向于非球形
Level 1 数据图像
Volcanic aerosol
颜色比：衡量粒子的相对大小 Cirrus
Water
《卫星气象学》电子课件（第一版）
Mexico
A dust storm occurred on August 17, 2006 over Sahara. Dust particles were lofted into the air up to an altitude of 7 km in the source and transported over the North Atlantic Ocean and finally into Gulf of Mexico over the next days. (Liu et al, JGR 08)

QAlibria QMS-C-AS-051-02 商品说明书

Multi-Touch System Dashboard
• Visual representation of system configuration
• Intuitive control • Quick access to system components
Handy VNA Tools
• S-parameter measurements • QuickView graphical tool for data
verification
Automatic Configuration of Probes, Substrates and Standards
• Easy and error-free operation for beginners
Configuration Monitor
• Tracking of the VNA type, probe configuration and calibration methods
Probe Configuration Tools
• Probe type and orientation • Intuitive VNA port mapping • Recently used models
Quick Access Widgets
• Calibration reference plane • Standards models • re-configuration
Intelligent Hardware Recognition
• Automated reconfiguration of the automated/manual work flow
• No need to configure VNA and probe system

SPEI和植被遥感信息监测西南地区干旱差异分析

农业机械学报第51卷第12期2020年12月doi：10.6041/j.issn.1000-1298.2020.12.020SPEI和植被遥感信息监测西南地区干旱差异分析史晓亮吴梦月丁皓（西安科技大学测绘科学与技术学院，西安710054）摘要：基于西南地区2000—2018年不同时间尺度的标准化降水蒸散指数（SPEI1、SPEI3、SPEI12）,应用线性趋势法和曼肯德尔检验（Mann-Kendall test,M K）法分析了西南地区气象干旱的时间变化特征，评价了日光诱导叶绿素荧光（SIF）、归一化植被指数（NDVI）以及增强型植被指数（EVI）等植被遥感数据对区域植被状况监测的有效性及差异性。

结果表明：2000—2018年西南地区SPEI整体上呈微弱增加趋势，其中,2000—2013年间，SPEI12呈下降趋势（趋势率为-0.05/（10a）,R2=0.295）,2014—2018年间，SPEI12时间序列呈上升趋势（趋势率为0.04/（10a）,R2=0.094），说明在气候变化背景下,近年来西南地区的干旱化趋势有所缓解。

SPEI12的趋势突变点发生在2016年和2017年。

相对于植被绿度指数NDVI和EVI,SIF对植被生长季发生的长期和短期干旱事件均表现岀较大负异常，说明SIF可快速获取水分胁迫下的植被光合作用信息。

森林、农田和草地的SIF与不同时间尺度气象干旱指数的相关性均高于NDVI和EVI,SIF对森林、农田及草地植被生态系统干旱监测的敏感性优于传统的植被绿度指数;草地的SIF与SPEI1的相关性更高（R=0.859,P<0.01）,其光合作用对短期水分胁迫最为敏感。

本研究可为西南地区干旱的综合应对、水资源管理调控及生态治理提供科学依据。

关键词：干旱；标准化降水蒸散指数；日光诱导叶绿素荧光；遥感；西南地区中图分类号：S423；S127文献标识码：A文章编号：1000-1298（2020）12_0184_09OSID：普Difference Analysis of SPEI and Vegetation Remote SensingInformation in Drought Monitoring in Southwest ChinaSHI Xiaoliang WU Mengyue DING Hao(College of Geomatics,Xi'an University of Science and Technology,Xi'an710054,China) Abstract:Since2000,drought has occurred frequently in Southwest China,which has seriously affected social production and ecological environment.Therefore，studying the temporal evolution characteristics of meteorological drought and its impact on vegetation growth can provide theoretical basis for scientific management of regional water resources and ecological control.Based on the monthly precipitation and temperature data of Southwest China from2000to2018,the standardized precipitation evapotranspiration index of different time scales was calculated.The linear trend method and Mann Kendall(M K)test were used to analyze the temporal variation characteristics of meteorological drought in Southwest China.The effectiveness and difference of solar-induced chlorophyll fluorescence(SIF),normalized differential vegetation index(NDVI)and enhanced vegetation index(EVI)in vegetation stress monitoring were evaluated.Furthermore，the response of vegetation to drought was also explored.The results showed that SPEI values showed a weak increasing trend in all time scales from2000to2018.From2000to2013, SPEI12showed a downward trend(the trend rate was-0.05/(10a),R2=0.295),and from2014to 2018,SPEI12time series showed an increasing trend(the trend rate was0.04/(10a),R2=0.094), indicating that the drought trend in Southwest China was alleviated in recent years under the background of climate change.The turning point of SPEI12time series occurred in2016and2017respectively.Compared with NDVI and EVI，SIF showed obvious negative anomalies for both long-term and short-term drought events during vegetation growing season，and it can quickly obtain the information of vegetation photosynthesis under water stress.The correlation between SIF of forest，farmland and grassland and meteorological drought index at different time scales was higher than NDVI and EVI，which meant that 收稿日期：20200822修回日期：20200923基金项目：国家自然科学基金项目(52079103)作者简介：史晓亮(1985—)，男，副教授，博士，主要从事资源环境遥感研究,E-mail：s_xiaoliang@第12期史晓亮等：SPEI和植被遥感信息监测西南地区干旱差异分析185the sensitivity of SIF of forest,farmland and grassland vegetation ecosystem to drought monitoring was better than that of traditional vegetation greenness index.The correlation between SIF of grassland and SPEI—1was higher(R=0.859,P<0.01),which indicated the grassland photosynthesis was more sensitive to short-term water stress.The research results can provide scientific basis for comprehensive drought coping，water resources management and ecological control in Southwest China.Key words:drought;standardized precipitation evapotranspiration index；solar-induced chlorophyll fluorescence；remote sensing；Southwest China0引言干旱是一种由于长期缺乏降水或降水偏少引发供求失衡的水分短缺现象,是全球范围内最复杂、最常见的自然灾害之一⑴。

费森尤斯4008系列血液透析机的质量控制_常玉锋

中国医疗设备 2014年第29卷 03期 V OL.29 No.0366QUALITY CONTROL伴随着慢性肾脏病发病率的上升以及全球人口老龄化的加速，慢性肾脏病已逐渐成为世界性的公共卫生问题，且呈现出流行性的特点。

血液透析作为肾脏替代治疗的主要方式之一，接受该治疗的患者数量也在日益增长[1]。

血液透析机的主要作用是：将患者血液在透析器中进行滤过，清除血液内的毒素、代谢废物及多余电解质，并将透析后的血液返回患者体内[2]。

血液透析机的各项技术参数是否可靠将直接影响病人透析治疗的效果，因此需要定期对血液透析机的各项技术参数进行质量控制以确保血液透析治疗的质量和安全[3]。

我院参照GB 9706.1-2007《医用电气设备第一部分：安全通用要求》、GB 9706.2-2003《医用电气设备第2-16部分：血液透析、血液透析滤过和血液滤过设备的安全专用要求》以及JJF 1353-2012《血液透析装置校准规范》，对在用的费森尤斯4008系列血液透析机的质量控制与技术检测进行了探索。

1 设备简介1.1 费森尤斯4008系列血液透析机4008血液透析机采用了模块化的设计理念，由控制单元、体外血液环路、透析液制备和超滤几大模块组成，可完成血液透析、血液滤过、血液透析滤过等多种透析功能；具有开机自检、安全检测和报警功能，可监测动脉压、静脉压、跨膜压、空气检测、漏血（破膜）、电导度等多种参数[4]。

1.2 ESA 612电气安全分析仪ESA 612电气安全分析仪是一款功能齐全、结构紧凑、携带方便的测试工具，融合有信号模拟器、万用表和电气安全分析等功能，可根据美国（ANSI/AAMI ES1、NFPA费森尤斯4008系列血液透析机的质量控制Quality Control of Fresenius 4008 Series Hemodialysis Machine[摘要] 目的探讨费森尤斯4008血液透析机在使用过程中的质量控制与技术检测方法。

211116242_便携式伽玛射线剂量（率）仪校准方法及应用的研究

科学研究创便携式伽玛射线剂量（率）仪校准方法及应用的研究杨柳（核工业大连应用技术研究所辽宁大连116031）摘　要：当下，关于伽玛射线剂量（率）仪的检定存在诸多不足，体现在周期、距离、效率等方面。

为寻求改善，提出基于小尺度参考辐射并借助样本仪表的机器预测方法，目的是使得遂行校准具备便携式和可移动式。

首先，论证基于小尺度参考辐射开展仪表校准的可行性，提出相应的实施框架和流程；其次，进行实物设计和研制；最后是实证检验。

结果表明，虽然新方式尚未达到最优效果，但仍能实现测量标准不确定度不大于5%。

随着进一步的改进，势必可作为苛刻条件下进行伽玛射线仪表校准的先行选择。

关键词：伽玛空气比释动能小尺度参考辐射校准因子机器学习中图分类号：P11文献标识码：A文章编号：1674-098X(2022)10(b)-0017-04 Research on Calibration Method and Application of PortableGamma Ray DosimeterYANG Liu( Dalian Applied Technology Research Institute of Nuclear Industry, Dalian, Liaoning Province,116031 China )Abstract: At present, there are many deficiencies in the verification of gamma ray dose (rate) instrument, which are reflected in the aspects of cycle, distance, efficiency and so on. In order to seek improvement, a machine predic‐tion method based on small-scale reference radiation and sample instrument is proposed in order to make the cali‐bration portable and mobile. Firstly, the feasibility of instrument calibration based on small-scale reference radiation is demonstrated, and the corresponding implementation framework and process are put forward. Secondly, carry out physical design and development. The last is empirical test. The results show that although the new method has not achieved the optimal effect, it can still achieve the measurement standard uncertainty of no more than 5%. With further improvement, it is bound to be the first choice for gamma ray instrument calibration under harsh conditions.Key Words: Gamma air specific release kinetic energy; Small scale reference radiation; Calibration factor;Machine learning检定伽玛射线剂量（率）仪时，不可避免地会有额外的散射伽玛射线产生，它们将对检点处的空气比释动能约定真值产生影响［1］，一般要求是低于5%。

An Overview of Recent Progress in the Study of Distributed Multi-agent Coordination

An Overview of Recent Progress in the Study of Distributed Multi-agent CoordinationYongcan Cao,Member,IEEE,Wenwu Yu,Member,IEEE,Wei Ren,Member,IEEE,and Guanrong Chen,Fellow,IEEEAbstract—This article reviews some main results and progress in distributed multi-agent coordination,focusing on papers pub-lished in major control systems and robotics journals since 2006.Distributed coordination of multiple vehicles,including unmanned aerial vehicles,unmanned ground vehicles and un-manned underwater vehicles,has been a very active research subject studied extensively by the systems and control community. The recent results in this area are categorized into several directions,such as consensus,formation control,optimization, and estimation.After the review,a short discussion section is included to summarize the existing research and to propose several promising research directions along with some open problems that are deemed important for further investigations.Index Terms—Distributed coordination,formation control,sen-sor networks,multi-agent systemI.I NTRODUCTIONC ONTROL theory and practice may date back to thebeginning of the last century when Wright Brothers attempted theirﬁrst testﬂight in1903.Since then,control theory has gradually gained popularity,receiving more and wider attention especially during the World War II when it was developed and applied toﬁre-control systems,missile nav-igation and guidance,as well as various electronic automation devices.In the past several decades,modern control theory was further advanced due to the booming of aerospace technology based on large-scale engineering systems.During the rapid and sustained development of the modern control theory,technology for controlling a single vehicle, albeit higher-dimensional and complex,has become relatively mature and has produced many effective tools such as PID control,adaptive control,nonlinear control,intelligent control, This work was supported by the National Science Foundation under CAREER Award ECCS-1213291,the National Natural Science Foundation of China under Grant No.61104145and61120106010,the Natural Science Foundation of Jiangsu Province of China under Grant No.BK2011581,the Research Fund for the Doctoral Program of Higher Education of China under Grant No.20110092120024,the Fundamental Research Funds for the Central Universities of China,and the Hong Kong RGC under GRF Grant CityU1114/11E.The work of Yongcan Cao was supported by a National Research Council Research Associateship Award at AFRL.Y.Cao is with the Control Science Center of Excellence,Air Force Research Laboratory,Wright-Patterson AFB,OH45433,USA.W.Yu is with the Department of Mathematics,Southeast University,Nanjing210096,China and also with the School of Electrical and Computer Engineering,RMIT University,Melbourne VIC3001,Australia.W.Ren is with the Department of Electrical Engineering,University of California,Riverside,CA92521,USA.G.Chen is with the Department of Electronic Engineering,City University of Hong Kong,Hong Kong SAR,China.Copyright(c)2009IEEE.Personal use of this material is permitted. However,permission to use this material for any other purposes must be obtained from the IEEE by sending a request to pubs-permissions@.and robust control methodologies.In the past two decades in particular,control of multiple vehicles has received increas-ing demands spurred by the fact that many beneﬁts can be obtained when a single complicated vehicle is equivalently replaced by multiple yet simpler vehicles.In this endeavor, two approaches are commonly adopted for controlling multiple vehicles:a centralized approach and a distributed approach. The centralized approach is based on the assumption that a central station is available and powerful enough to control a whole group of vehicles.Essentially,the centralized ap-proach is a direct extension of the traditional single-vehicle-based control philosophy and strategy.On the contrary,the distributed approach does not require a central station for control,at the cost of becoming far more complex in structure and organization.Although both approaches are considered practical depending on the situations and conditions of the real applications,the distributed approach is believed more promising due to many inevitable physical constraints such as limited resources and energy,short wireless communication ranges,narrow bandwidths,and large sizes of vehicles to manage and control.Therefore,the focus of this overview is placed on the distributed approach.In distributed control of a group of autonomous vehicles,the main objective typically is to have the whole group of vehicles working in a cooperative fashion throughout a distributed pro-tocol.Here,cooperative refers to a close relationship among all vehicles in the group where information sharing plays a central role.The distributed approach has many advantages in achieving cooperative group performances,especially with low operational costs,less system requirements,high robustness, strong adaptivity,andﬂexible scalability,therefore has been widely recognized and appreciated.The study of distributed control of multiple vehicles was perhapsﬁrst motivated by the work in distributed comput-ing[1],management science[2],and statistical physics[3]. In the control systems society,some pioneering works are generally referred to[4],[5],where an asynchronous agree-ment problem was studied for distributed decision-making problems.Thereafter,some consensus algorithms were studied under various information-ﬂow constraints[6]–[10].There are several journal special issues on the related topics published af-ter2006,including the IEEE Transactions on Control Systems Technology(vol.15,no.4,2007),Proceedings of the IEEE (vol.94,no.4,2007),ASME Journal of Dynamic Systems, Measurement,and Control(vol.129,no.5,2007),SIAM Journal of Control and Optimization(vol.48,no.1,2009),and International Journal of Robust and Nonlinear Control(vol.21,no.12,2011).In addition,there are some recent reviewsand progress reports given in the surveys[11]–[15]and thebooks[16]–[23],among others.This article reviews some main results and recent progressin distributed multi-agent coordination,published in majorcontrol systems and robotics journals since2006.Due to space limitations,we refer the readers to[24]for a more completeversion of the same overview.For results before2006,thereaders are referred to[11]–[14].Speciﬁcally,this article reviews the recent research resultsin the following directions,which are not independent but actually may have overlapping to some extent:1.Consensus and the like(synchronization,rendezvous).Consensus refers to the group behavior that all theagents asymptotically reach a certain common agreementthrough a local distributed protocol,with or without predeﬁned common speed and orientation.2.Distributed formation and the like(ﬂocking).Distributedformation refers to the group behavior that all the agents form a pre-designed geometrical conﬁguration throughlocal interactions with or without a common reference.3.Distributed optimization.This refers to algorithmic devel-opments for the analysis and optimization of large-scaledistributed systems.4.Distributed estimation and control.This refers to dis-tributed control design based on local estimation aboutthe needed global information.The rest of this article is organized as follows.In Section II,basic notations of graph theory and stochastic matrices are introduced.Sections III,IV,V,and VI describe the recentresearch results and progress in consensus,formation control, optimization,and estimation.Finally,the article is concludedby a short section of discussions with future perspectives.II.P RELIMINARIESA.Graph TheoryFor a system of n connected agents,its network topology can be modeled as a directed graph denoted by G=(V,W),where V={v1,v2,···,v n}and W⊆V×V are,respectively, the set of agents and the set of edges which directionallyconnect the agents together.Speciﬁcally,the directed edgedenoted by an ordered pair(v i,v j)means that agent j can access the state information of agent i.Accordingly,agent i is a neighbor of agent j.A directed path is a sequence of directed edges in the form of(v1,v2),(v2,v3),···,with all v i∈V.A directed graph has a directed spanning tree if there exists at least one agent that has a directed path to every other agent.The union of a set of directed graphs with the same setof agents,{G i1,···,G im},is a directed graph with the sameset of agents and its set of edges is given by the union of the edge sets of all the directed graphs G ij,j=1,···,m.A complete directed graph is a directed graph in which each pair of distinct agents is bidirectionally connected by an edge,thus there is a directed path from any agent to any other agent in the network.Two matrices are used to represent the network topology: the adjacency matrix A=[a ij]∈R n×n with a ij>0if (v j,v i)∈W and a ij=0otherwise,and the Laplacian matrix L=[ℓij]∈R n×n withℓii= n j=1a ij andℓij=−a ij,i=j, which is generally asymmetric for directed graphs.B.Stochastic MatricesA nonnegative square matrix is called(row)stochastic matrix if its every row is summed up to one.The product of two stochastic matrices is still a stochastic matrix.A row stochastic matrix P∈R n×n is called indecomposable and aperiodic if lim k→∞P k=1y T for some y∈R n[25],where 1is a vector with all elements being1.III.C ONSENSUSConsider a group of n agents,each with single-integrator kinematics described by˙x i(t)=u i(t),i=1,···,n,(1) where x i(t)and u i(t)are,respectively,the state and the control input of the i th agent.A typical consensus control algorithm is designed asu i(t)=nj=1a ij(t)[x j(t)−x i(t)],(2)where a ij(t)is the(i,j)th entry of the corresponding ad-jacency matrix at time t.The main idea behind(2)is that each agent moves towards the weighted average of the states of its neighbors.Given the switching network pattern due to the continuous motions of the dynamic agents,coupling coefﬁcients a ij(t)in(2),hence the graph topologies,are generally time-varying.It is shown in[9],[10]that consensus is achieved if the underlying directed graph has a directed spanning tree in some jointly fashion in terms of a union of its time-varying graph topologies.The idea behind consensus serves as a fundamental principle for the design of distributed multi-agent coordination algo-rithms.Therefore,investigating consensus has been a main research direction in the study of distributed multi-agent co-ordination.To bridge the gap between the study of consensus algorithms and many physical properties inherited in practical systems,it is necessary and meaningful to study consensus by considering many practical factors,such as actuation,control, communication,computation,and vehicle dynamics,which characterize some important features of practical systems.This is the main motivation to study consensus.In the following part of the section,an overview of the research progress in the study of consensus is given,regarding stochastic network topologies and dynamics,complex dynamical systems,delay effects,and quantization,mainly after2006.Several milestone results prior to2006can be found in[2],[4]–[6],[8]–[10], [26].A.Stochastic Network Topologies and DynamicsIn multi-agent systems,the network topology among all vehicles plays a crucial role in determining consensus.The objective here is to explicitly identify necessary and/or sufﬁ-cient conditions on the network topology such that consensus can be achieved under properly designed algorithms.It is often reasonable to consider the case when the network topology is deterministic under ideal communication chan-nels.Accordingly,main research on the consensus problem was conducted under a deterministicﬁxed/switching network topology.That is,the adjacency matrix A(t)is deterministic. Some other times,when considering random communication failures,random packet drops,and communication channel instabilities inherited in physical communication channels,it is necessary and important to study consensus problem in the stochastic setting where a network topology evolves according to some random distributions.That is,the adjacency matrix A(t)is stochastically evolving.In the deterministic setting,consensus is said to be achieved if all agents eventually reach agreement on a common state. In the stochastic setting,consensus is said to be achieved almost surely(respectively,in mean-square or in probability)if all agents reach agreement on a common state almost surely (respectively,in mean-square or with probability one).Note that the problem studied in the stochastic setting is slightly different from that studied in the deterministic setting due to the different assumptions in terms of the network topology. Consensus over a stochastic network topology was perhaps ﬁrst studied in[27],where some sufﬁcient conditions on the network topology were given to guarantee consensus with probability one for systems with single-integrator kinemat-ics(1),where the rate of convergence was also studied.Further results for consensus under a stochastic network topology were reported in[28]–[30],where research effort was conducted for systems with single-integrator kinematics[28],[29]or double-integrator dynamics[30].Consensus for single-integrator kine-matics under stochastic network topology has been exten-sively studied in particular,where some general conditions for almost-surely consensus was derived[29].Loosely speaking, almost-surely consensus for single-integrator kinematics can be achieved,i.e.,x i(t)−x j(t)→0almost surely,if and only if the expectation of the network topology,namely,the network topology associated with expectation E[A(t)],has a directed spanning tree.It is worth noting that the conditions are analogous to that in[9],[10],but in the stochastic setting. In view of the special structure of the closed-loop systems concerning consensus for single-integrator kinematics,basic properties of the stochastic matrices play a crucial role in the convergence analysis of the associated control algorithms. Consensus for double-integrator dynamics was studied in[30], where the switching network topology is assumed to be driven by a Bernoulli process,and it was shown that consensus can be achieved if the union of all the graphs has a directed spanning tree.Apparently,the requirement on the network topology for double-integrator dynamics is a special case of that for single-integrator kinematics due to the difference nature of theﬁnal states(constantﬁnal states for single-integrator kinematics and possible dynamicﬁnal states for double-integrator dynamics) caused by the substantial dynamical difference.It is still an open question as if some general conditions(corresponding to some speciﬁc algorithms)can be found for consensus with double-integrator dynamics.In addition to analyzing the conditions on the network topology such that consensus can be achieved,a special type of consensus algorithm,the so-called gossip algorithm[31],[32], has been used to achieve consensus in the stochastic setting. The gossip algorithm can always guarantee consensus almost surely if the available pairwise communication channels satisfy certain conditions(such as a connected graph).The way of network topology switching does not play any role in the consideration of consensus.The current study on consensus over stochastic network topologies has shown some interesting results regarding:(1) consensus algorithm design for various multi-agent systems,(2)conditions of the network topologies on consensus,and(3)effects of the stochastic network topologies on the con-vergence rate.Future research on this topic includes,but not limited to,the following two directions:(1)when the network topology itself is stochastic,how to determine the probability of reaching consensus almost surely?(2)compared with the deterministic network topology,what are the advantages and disadvantages of the stochastic network topology,regarding such as robustness and convergence rate?As is well known,disturbances and uncertainties often exist in networked systems,for example,channel noise,commu-nication noise,uncertainties in network parameters,etc.In addition to the stochastic network topologies discussed above, the effect of stochastic disturbances[33],[34]and uncertain-ties[35]on the consensus problem also needs investigation. Study has been mainly devoted to analyzing the performance of consensus algorithms subject to disturbances and to present-ing conditions on the uncertainties such that consensus can be achieved.In addition,another interesting direction in dealing with disturbances and uncertainties is to design distributed localﬁltering algorithms so as to save energy and improve computational efﬁciency.Distributed localﬁltering algorithms play an important role and are more effective than traditional centralizedﬁltering algorithms for multi-agent systems.For example,in[36]–[38]some distributed Kalmanﬁlters are designed to implement data fusion.In[39],by analyzing consensus and pinning control in synchronization of complex networks,distributed consensusﬁltering in sensor networks is addressed.Recently,Kalmanﬁltering over a packet-dropping network is designed through a probabilistic approach[40]. Today,it remains a challenging problem to incorporate both dynamics of consensus and probabilistic(Kalman)ﬁltering into a uniﬁed framework.plex Dynamical SystemsSince consensus is concerned with the behavior of a group of vehicles,it is natural to consider the system dynamics for practical vehicles in the study of the consensus problem. Although the study of consensus under various system dynam-ics is due to the existence of complex dynamics in practical systems,it is also interesting to observe that system dynamics play an important role in determining theﬁnal consensus state.For instance,the well-studied consensus of multi-agent systems with single-integrator kinematics often converges to a constantﬁnal value instead.However,consensus for double-integrator dynamics might admit a dynamicﬁnal value(i.e.,a time function).These important issues motivate the study of consensus under various system dynamics.As a direct extension of the study of the consensus prob-lem for systems with simple dynamics,for example,with single-integrator kinematics or double-integrator dynamics, consensus with general linear dynamics was also studied recently[41]–[43],where research is mainly devoted toﬁnding feedback control laws such that consensus(in terms of the output states)can be achieved for general linear systems˙x i=Ax i+Bu i,y i=Cx i,(3) where A,B,and C are constant matrices with compatible sizes.Apparently,the well-studied single-integrator kinematics and double-integrator dynamics are special cases of(3)for properly choosing A,B,and C.As a further extension,consensus for complex systems has also been extensively studied.Here,the term consensus for complex systems is used for the study of consensus problem when the system dynamics are nonlinear[44]–[48]or with nonlinear consensus algorithms[49],[50].Examples of the nonlinear system dynamics include:•Nonlinear oscillators[45].The dynamics are often as-sumed to be governed by the Kuramoto equation˙θi=ωi+Kstability.A well-studied consensus algorithm for(1)is given in(2),where it is now assumed that time delay exists.Two types of time delays,communication delay and input delay, have been considered in the munication delay accounts for the time for transmitting information from origin to destination.More precisely,if it takes time T ij for agent i to receive information from agent j,the closed-loop system of(1)using(2)under aﬁxed network topology becomes˙x i(t)=nj=1a ij(t)[x j(t−T ij)−x i(t)].(7)An interpretation of(7)is that at time t,agent i receives information from agent j and uses data x j(t−T ij)instead of x j(t)due to the time delay.Note that agent i can get its own information instantly,therefore,input delay can be considered as the summation of computation time and execution time. More precisely,if the input delay for agent i is given by T p i, then the closed-loop system of(1)using(2)becomes˙x i(t)=nj=1a ij(t)[x j(t−T p i)−x i(t−T p i)].(8)Clearly,(7)refers to the case when only communication delay is considered while(8)refers to the case when only input delay is considered.It should be emphasized that both communication delay and input delay might be time-varying and they might co-exist at the same time.In addition to time delay,it is also important to consider packet drops in exchanging state information.Fortunately, consensus with packet drops can be considered as a special case of consensus with time delay,because re-sending packets after they were dropped can be easily done but just having time delay in the data transmission channels.Thus,the main problem involved in consensus with time delay is to study the effects of time delay on the convergence and performance of consensus,referred to as consensusabil-ity[52].Because time delay might affect the system stability,it is important to study under what conditions consensus can still be guaranteed even if time delay exists.In other words,can oneﬁnd conditions on the time delay such that consensus can be achieved?For this purpose,the effect of time delay on the consensusability of(1)using(2)was investigated.When there exists only(constant)input delay,a sufﬁcient condition on the time delay to guarantee consensus under aﬁxed undirected interaction graph is presented in[8].Speciﬁcally,an upper bound for the time delay is derived under which consensus can be achieved.This is a well-expected result because time delay normally degrades the system performance gradually but will not destroy the system stability unless the time delay is above a certain threshold.Further studies can be found in, e.g.,[53],[54],which demonstrate that for(1)using(2),the communication delay does not affect the consensusability but the input delay does.In a similar manner,consensus with time delay was studied for systems with different dynamics, where the dynamics(1)are replaced by other more complex ones,such as double-integrator dynamics[55],[56],complex networks[57],[58],rigid bodies[59],[60],and general nonlinear dynamics[61].In summary,the existing study of consensus with time delay mainly focuses on analyzing the stability of consensus algo-rithms with time delay for various types of system dynamics, including linear and nonlinear dynamics.Generally speaking, consensus with time delay for systems with nonlinear dynam-ics is more challenging.For most consensus algorithms with time delays,the main research question is to determine an upper bound of the time delay under which time delay does not affect the consensusability.For communication delay,it is possible to achieve consensus under a relatively large time delay threshold.A notable phenomenon in this case is that theﬁnal consensus state is constant.Considering both linear and nonlinear system dynamics in consensus,the main tools for stability analysis of the closed-loop systems include matrix theory[53],Lyapunov functions[57],frequency-domain ap-proach[54],passivity[58],and the contraction principle[62]. Although consensus with time delay has been studied extensively,it is often assumed that time delay is either constant or random.However,time delay itself might obey its own dynamics,which possibly depend on the communication distance,total computation load and computation capability, etc.Therefore,it is more suitable to represent the time delay as another system variable to be considered in the study of the consensus problem.In addition,it is also important to consider time delay and other physical constraints simultaneously in the study of the consensus problem.D.QuantizationQuantized consensus has been studied recently with motiva-tion from digital signal processing.Here,quantized consensus refers to consensus when the measurements are digital rather than analog therefore the information received by each agent is not continuous and might have been truncated due to digital ﬁnite precision constraints.Roughly speaking,for an analog signal s,a typical quantizer with an accuracy parameterδ, also referred to as quantization step size,is described by Q(s)=q(s,δ),where Q(s)is the quantized signal and q(·,·) is the associated quantization function.For instance[63],a quantizer rounding a signal s to its nearest integer can be expressed as Q(s)=n,if s∈[(n−1/2)δ,(n+1/2)δ],n∈Z, where Z denotes the integer set.Note that the types of quantizers might be different for different systems,hence Q(s) may differ for different systems.Due to the truncation of the signals received,consensus is now considered achieved if the maximal state difference is not larger than the accuracy level associated with the whole system.A notable feature for consensus with quantization is that the time to reach consensus is usuallyﬁnite.That is,it often takes aﬁnite period of time for all agents’states to converge to an accuracy interval.Accordingly,the main research is to investigate the convergence time associated with the proposed consensus algorithm.Quantized consensus was probablyﬁrst studied in[63], where a quantized gossip algorithm was proposed and its convergence was analyzed.In particular,the bound of theconvergence time for a complete graph was shown to be poly-nomial in the network size.In[64],coding/decoding strate-gies were introduced to the quantized consensus algorithms, where it was shown that the convergence rate depends on the accuracy of the quantization but not the coding/decoding schemes.In[65],quantized consensus was studied via the gossip algorithm,with both lower and upper bounds of the expected convergence time in the worst case derived in terms of the principle submatrices of the Laplacian matrix.Further results regarding quantized consensus were reported in[66]–[68],where the main research was also on the convergence time for various proposed quantized consensus algorithms as well as the quantization effects on the convergence time.It is intuitively reasonable that the convergence time depends on both the quantization level and the network topology.It is then natural to ask if and how the quantization methods affect the convergence time.This is an important measure of the robustness of a quantized consensus algorithm(with respect to the quantization method).Note that it is interesting but also more challenging to study consensus for general linear/nonlinear systems with quantiza-tion.Because the difference between the truncated signal and the original signal is bounded,consensus with quantization can be considered as a special case of one without quantization when there exist bounded disturbances.Therefore,if consensus can be achieved for a group of vehicles in the absence of quantization,it might be intuitively correct to say that the differences among the states of all vehicles will be bounded if the quantization precision is small enough.However,it is still an open question to rigorously describe the quantization effects on consensus with general linear/nonlinear systems.E.RemarksIn summary,the existing research on the consensus problem has covered a number of physical properties for practical systems and control performance analysis.However,the study of the consensus problem covering multiple physical properties and/or control performance analysis has been largely ignored. In other words,two or more problems discussed in the above subsections might need to be taken into consideration simul-taneously when studying the consensus problem.In addition, consensus algorithms normally guarantee the agreement of a team of agents on some common states without taking group formation into consideration.To reﬂect many practical applications where a group of agents are normally required to form some preferred geometric structure,it is desirable to consider a task-oriented formation control problem for a group of mobile agents,which motivates the study of formation control presented in the next section.IV.F ORMATION C ONTROLCompared with the consensus problem where theﬁnal states of all agents typically reach a singleton,theﬁnal states of all agents can be more diversiﬁed under the formation control scenario.Indeed,formation control is more desirable in many practical applications such as formationﬂying,co-operative transportation,sensor networks,as well as combat intelligence,surveillance,and reconnaissance.In addition,theperformance of a team of agents working cooperatively oftenexceeds the simple integration of the performances of all individual agents.For its broad applications and advantages,formation control has been a very active research subject inthe control systems community,where a certain geometric pattern is aimed to form with or without a group reference.More precisely,the main objective of formation control is to coordinate a group of agents such that they can achievesome desired formation so that some tasks can beﬁnished bythe collaboration of the agents.Generally speaking,formation control can be categorized according to the group reference.Formation control without a group reference,called formationproducing,refers to the algorithm design for a group of agents to reach some pre-desired geometric pattern in the absenceof a group reference,which can also be considered as the control objective.Formation control with a group reference,called formation tracking,refers to the same task but followingthe predesignated group reference.Due to the existence of the group reference,formation tracking is usually much morechallenging than formation producing and control algorithmsfor the latter might not be useful for the former.As of today, there are still many open questions in solving the formationtracking problem.The following part of the section reviews and discussesrecent research results and progress in formation control, including formation producing and formation tracking,mainlyaccomplished after2006.Several milestone results prior to 2006can be found in[69]–[71].A.Formation ProducingThe existing work in formation control aims at analyzingthe formation behavior under certain control laws,along with stability analysis.1)Matrix Theory Approach:Due to the nature of multi-agent systems,matrix theory has been frequently used in thestability analysis of their distributed coordination.Note that consensus input to each agent(see e.g.,(2))isessentially a weighted average of the differences between the states of the agent’s neighbors and its own.As an extensionof the consensus algorithms,some coupling matrices wereintroduced here to offset the corresponding control inputs by some angles[72],[73].For example,given(1),the controlinput(2)is revised as u i(t)= n j=1a ij(t)C[x j(t)−x i(t)], where C is a coupling matrix with compatible size.If x i∈R3, then C can be viewed as the3-D rotational matrix.The mainidea behind the revised algorithm is that the original controlinput for reaching consensus is now rotated by some angles. The closed-loop system can be expressed in a vector form, whose stability can be determined by studying the distribution of the eigenvalues of a certain transfer matrix.Main research work was conducted in[72],[73]to analyze the collective motions for systems with single-integrator kinematics and double-integrator dynamics,where the network topology,the damping gain,and C were shown to affect the collective motions.Analogously,the collective motions for a team of nonlinear self-propelling agents were shown to be affected by。

【豆丁-精品】-一种基于多灭点标定数码相机内外参数的方法

第41卷第5期四川大学学报(工程科学版)Vol.41No.5 2009年9月JOURNAL OF SI CHUAN UN I V ERSI TY(ENGI N EER I N G SC I ENCE ED I TI O N)Sep t.2009 文章编号:100923087(2009)0520193204一种基于多灭点标定数码相机内外参数的方法王德麾,樊庆文3,袁中凡(四川大学制造科学与工程学院,四川成都610065)摘　要:提高相机定标精度,简化定标过程,是计算机视觉研究的重要内容。

利用包含至少4组平行线和两个定标点的模板,对模板一次拍照即可标定相机内外参数。

先利用Hough变换,检测出模板图像中的各直线,确定对应的灭点;再把灭点坐标及已知的各组平行线的方向向量代入隐参数矩阵计算方程,得到相机的隐参数矩阵;最后对隐参数矩阵进行分解,依次得到相机的内部参数矩阵和旋转矩阵,然后利用模板中两个已知空间坐标的定标点计算相机的位移矩阵。

该方法的求解过程仅涉及到线性方程组的求解,定标精度高、稳定性好,与基于主灭点的定标法相比,不需要相机做任何运动,定标过程简单,具有一定的理论意义和实用价值。

关键词:相机定标;灭点;Hough变换;直线检测中图分类号:X703文献标识码:ACa li bra ti on of Cam era’s A ll Param eters w ith Van ish i n g Po i n tsWAN G D e2hui,FAN Q ing2w en,YUAN Zhong2fan(School of Manufacturing Sci.and Eng.,Sichuan Univ.,Chengdu610065,China)Abstract:The most i m portant m issi on in the field of the computer visi on is how t o i m p r ove the p recisi on of the ca m2 era’s scaling and si m p lify the scaling p r ocess.For this pur pose,a ne w method t o calibrate the ca mera’s all interi or and exteri or para meters using at least4directi ons vanishing points and2calibratinon points is br ought f or ward.It only needs one i m age of the te mp late.Then the Hough transfor m is used t o detect lines in the i m age and the vanis2 hing points in each directi ons are l ocated.The ca mera2calibrating equati ons and the positi ons of the vanishing points are app lied t o res olve the ca mera’s i m p licit para meters matrix.Finally,the matrix are divded int o the ca mera’s in2 teri or and exteri or para meters according t o the matrix’s characteristic and accomp lish the calibrati pared with other calibrating ways,this method is more facility and p recise.Key words:ca mera calibrati on;vanishing point;hough transfor m;line detecti on 通过二维序列图像恢复三维景物的欧氏(Eu2 clidean)信息,标定线性相机的内部参数矩阵,旋转矩阵和平移向量,是计算机视觉的主要研究问题之一[1]。

FastSLAM A factored solution to the simultaneous localization and mapping problem

FastSLAM:A Factored Solution to the Simultaneous Localization and Mapping ProblemMichael Montemerlo and Sebastian Thrun School of Computer ScienceCarnegie Mellon UniversityPittsburgh,PA15213mmde@,thrun@ Daphne Koller and Ben Wegbreit Computer Science DepartmentStanford UniversityStanford,CA94305-9010koller@,ben@AbstractThe ability to simultaneously localize a robot and ac-curately map its surroundings is considered by many tobe a key prerequisite of truly autonomous robots.How-ever,few approaches to this problem scale up to handlethe very large number of landmarks present in real envi-ronments.Kalmanﬁlter-based algorithms,for example,require time quadratic in the number of landmarks to in-corporate each sensor observation.This paper presentsFastSLAM,an algorithm that recursively estimates thefull posterior distribution over robot pose and landmarklocations,yet scales logarithmically with the number oflandmarks in the map.This algorithm is based on an ex-act factorization of the posterior into a product of con-ditional landmark distributions and a distribution overrobot paths.The algorithm has been run successfullyon as many as50,000landmarks,environments far be-yond the reach of previous approaches.Experimentalresults demonstrate the advantages and limitations ofthe FastSLAM algorithm on both simulated and real-world data.IntroductionThe problem of simultaneous localization and mapping,also known as SLAM,has attracted immense attention in the mo-bile robotics literature.SLAM addresses the problem of building a map of an environment from a sequence of land-mark measurements obtained from a moving robot.Since robot motion is subject to error,the mapping problem neces-sarily induces a robot localization problem—hence the name SLAM.The ability to simultaneously localize a robot and accurately map its environment is considered by many to be a key prerequisite of truly autonomous robots[3,7,16]. The dominant approach to the SLAM problem was in-troduced in a seminal paper by Smith,Self,and Cheese-man[15].This paper proposed the use of the extended Kalmanﬁlter(EKF)for incrementally estimating the poste-rior distribution over robot pose along with the positions of the landmarks.In the last decade,this approach has found widespread acceptance inﬁeld robotics,as a recent tutorial paper[2]documents.Recent research has focused on scal-ing this approach to larger environments with more than aFigure1:The SLAM problem:The robot moves from pose through a sequence of controls,.As it moves,it observes nearby landmarks.At time,it observes landmark out of two landmarks,.The measurement is denoted (range and bearing).At time,it observes the other landmark, ,and at time,it observes again.The SLAM problem is concerned with estimating the locations of the landmarks and the robot’s path from the controls and the measurements.The gray shading illustrates a conditional independence relation.plementation of this idea leads to an algorithm that requires time,where is the number of particles in the particleﬁlter and is the number of landmarks.We de-velop a tree-based data structure that reduces the running time of FastSLAM to,making it signiﬁcantly faster than existing EKF-based SLAM algorithms.We also extend the FastSLAM algorithm to situations with unknown data association and unknown number of landmarks,show-ing that our approach can be extended to the full range of SLAM problems discussed in the literature. Experimental results using a physical robot and a robot simulator illustrate that the FastSLAM algorithm can han-dle orders of magnitude more landmarks than present day approaches.We alsoﬁnd that in certain situations,an in-creased number of landmarks leads to a mild reduction of the number of particles needed to generate accurate maps—whereas in others the number of particles required for accurate mapping may be prohibitively large.SLAM Problem DeﬁnitionThe SLAM problem,as deﬁned in the rich body of litera-ture on SLAM,is best described as a probabilistic Markov chain.The robot’s pose at time will be denoted.For robots operating in the plane—which is the case in all of our experiments—poses are comprised of a robot’s-coordi-nate in the plane and its heading direction.Poses evolve according to a probabilistic law,often re-ferred to as the motion model:(1) Thus,is a probabilistic function of the robot control and the previous pose.In mobile robotics,the motion model is usually a time-invariant probabilistic generalization of robot kinematics[1].The robot’s environment possesses immobile land-marks.Each landmark is characterized by its location in space,denoted for.Without loss of gen-erality,we will think of landmarks as points in the plane,so that locations are speciﬁed by two numerical values.To map its environment,the robot can sense landmarks. For example,it may be able to measure range and bearing to a landmark,relative to its local coordinate frame.The mea-surement at time will be denoted.While robots can often sense more than one landmark at a time,we follow com-monplace notation by assuming that sensor measurements correspond to exactly one landmark[2].This convention is adopted solely for mathematical convenience.It poses no restriction,as multiple landmark sightings at a single time step can be processed sequentially.Sensor measurements are governed by a probabilistic law, often referred to as the measurement model:(2) Here is the set of all landmarks,andis the index of the landmark perceived at time.For example,in Figure1,we have, and,since the robotﬁrst observes landmark, then landmark,andﬁnally landmark for a second time. Many measurement models in the literature assume that the robot can measure range and bearing to landmarks,con-founded by measurement noise.The variable is often referred to as correspondence.Most theoretical work in the literature assumes knowledge of the correspondence or,put differently,that landmarks are uniquely identiﬁable.Practi-cal implementations use maximum likelihood estimators for estimating the correspondence on-the-ﬂy,which work well if landmarks are spaced sufﬁciently far apart.In large parts of this paper we will simply assume that landmarks are iden-tiﬁable,but we will also discuss an extension that estimates the correspondences from data.We are now ready to formulate the SLAM problem.Most generally,SLAM is the problem of determining the location of all landmarks and robot poses from measurementsand controls.In probabilis-tic terms,this is expressed by the posterior, where we use the superscript to refer to a set of variables from time1to time.If the correspondences are known,the SLAM problem is simpler:(3) As discussed in the introduction,all individual landmark es-timation problems are independent if one knew the robot’s path and the correspondence variables.This condi-tional independence is the basis of the FastSLAM algorithm described in the next section.FastSLAM with Known Correspondences We begin our consideration with the important case where the correspondences are known,and so is the number of landmarks observed thus far.Factored RepresentationThe conditional independence property of the SLAM prob-lem implies that the posterior(3)can be factored as follows:(4)Put verbally,the problem can be decomposed into esti-mation problems,one problem of estimating a posterior over robot paths,and problems of estimating the locationsof the landmarks conditioned on the path estimate.This factorization is exact and always applicable in the SLAM problem,as previously argued in[12].The FastSLAM algorithm implements the path estimatorusing a modiﬁed particleﬁlter[4].As we argue further below,thisﬁlter can sample efﬁciently from this space,providing a good approximation of the poste-rior even under non-linear motion kinematics.The land-mark pose estimators are realized by Kalmanﬁlters,using separateﬁlters for different landmarks. Because the landmark estimates are conditioned on the path estimate,each particle in the particleﬁlter has its own,lo-cal landmark estimates.Thus,for particles and land-marks,there will be a total of Kalmanﬁlters,each of dimension2(for the two landmark coordinates).This repre-sentation will now be discussed in detail.Particle Filter Path EstimationFastSLAM employs a particleﬁlter for estimating the path posterior in(4),using aﬁlter that is similar (but not identical)to the Monte Carlo localization(MCL) algorithm[1].MCL is an application of particleﬁlter tothe problem of robot pose estimation(localization).At each point in time,both algorithms maintain a set of particles rep-resenting the posterior,denoted.Each particle represents a“guess”of the robot’s path:(5) We use the superscript notation to refer to the-th par-ticle in the set.The particle set is calculated incrementally,from theset at time,a robot control,and a measurement.First,each particle in is used to generate a probabilistic guess of the robot’s pose at time:(6) obtained by sampling from the probabilistic motion model. This estimate is then added to a temporary set of parti-cles,along with the path.Under the assumption that the set of particles in is distributed according to(which is an asymptotically cor-rect approximation),the new particle is distributed accord-ing to.This distribution is commonly referred to as the proposal distribution of particleﬁltering. After generating particles in this way,the new set is obtained by sampling from the temporary particle set.Each particle is drawn(with replacement)with a probability proportional to a so-called importance factor,which is calculated as follows[10]:target distribution(7) The exact calculation of(7)will be discussed further below. The resulting sample set is distributed according to an ap-proximation to the desired pose posterior,an approximation which is correct as the number of particlesgoes to inﬁnity.We also notice that only the most recent robot pose estimate is used when generating the parti-cle set.This will allows us to silently“forget”all other pose estimates,rendering the size of each particle indepen-dent of the time index.Landmark Location EstimationFastSLAM represents the conditional landmark estimatesin(4)by Kalmanﬁlters.Since this estimate is conditioned on the robot pose,the Kalmanﬁlters are attached to individual pose particles in.More speciﬁ-cally,the full posterior over paths and landmark positions in the FastSLAM algorithm is represented by the sample set(8) Here and are mean and covariance of the Gaus-sian representing the-th landmark,attached to the-th particle.In the planar robot navigation scenario,each mean is a two-element vector,and is a2by2matrix. The posterior over the-th landmark pose is easily ob-tained.Its computation depends on whether or not, that is,whether or not was observed at time.For, we obtain(9)For,we simply leave the Gaussian unchanged:(10) The FastSLAM algorithm implements the update equation (9)using the extended Kalmanﬁlter(EKF).As in existing EKF approaches to SLAM,thisﬁlter uses a linearized ver-sion of the perceptual model[2].Thus, FastSLAM’s EKF is similar to the traditional EKF for SLAM[15]in that it approximates the measurement model using a linear Gaussian function.We note that,with a lin-ear Gaussian observation model,the resulting distributionis exactly a Gaussian,even if the mo-tion model is not linear.This is a consequence of the use of sampling to approximate the distribution over the robot’s pose.One signiﬁcant difference between the FastSLAM algo-rithm’s use of Kalmanﬁlters and that of the traditional SLAM algorithm is that the updates in the FastSLAM algo-rithm involve only a Gaussian of dimension two(for the two landmark location parameters),whereas in the EKF-based SLAM approach a Gaussian of size has to be updated (with landmarks and3robot pose parameters).This cal-culation can be done in constant time in FastSLAM,whereas it requires time quadratic in in standard SLAM. Calculating the Importance WeightsLet us now return to the problem of calculating the impor-tance weights needed for particleﬁlter resampling,as deﬁned in(7):µµµµµµµµ8,Σ87,Σ76,Σ65,Σ54,Σ43,Σ32,Σ21,Σ1[m][m][m][m][m][m][m][m][m][m][m][m][m][m][m][m]Figure 2:A tree representinglandmark estimates within asingle particle.(a)(b)(c)Figure4:(a)Physical robot mapping rocks,in a testbed developed for Mars Rover research.(b)Raw range and path data.(c)Map generated using FastSLAM(dots),and locations of rocks determined manually(circles).in the map.It also has to determine if a measurement cor-responds to a new,previously unseen landmark,in whichcase the map should be augmented accordingly.In most existing SLAM solutions based on EKFs,theseproblems are solved via maximum likelihood.More specif-ically,the probability of a data association is given by(12)The step labeled“PF”uses the particleﬁlter approxima-tion to the posterior.Theﬁnal step assumesa uniform prior,which is commonly used[2].The maximum likelihood data association is simply the in-dex that maximizes(12).If the maximum value of—with careful consideration of all constantsin(12)—is below a threshold,the landmark is consideredpreviously unseen and the map is augmented accordingly.In FastSLAM,the data association is estimated on a per-particle basis:.As a result,different particles may rely on different values of.Theymight even possess different numbers of landmarks in theirrespective maps.This constitutes a primary difference toEKF approaches,which determine the data association onlyonce for each sensor measurement.It has been observedfrequently that false data association will make the conven-tional EKF approach fail catastrophically[2].FastSLAM ismore likely to recover,thanks to its ability to pursue multi-ple data associations simultaneously.Particles with wrongdata association are(in expectation)more likely to disap-pear in the resampling process than those that guess the dataassociation correctly.We believe that,under mild assumptions(e.g.,minimumspacing between landmarks and bounded sensor error),thedata association search can be implemented in time loga-rithmic in.One possibility is the use of kd-trees as anindexing scheme in the tree structures above,instead of thelandmark number,as proposed in[11].Experimental ResultsThe FastSLAM algorithm was tested extensively under vari-ous conditions.Real-world experiments were complimentedby systematic simulation experiments,to investigate thescaling abilities of the approach.Overall,the results indicatefavorably scaling to large number of landmarks and smallparticle sets.Aﬁxed number of particles(e.g.,)appears to work well across a large number of situations.Figure4a shows the physical robot testbed,which consistsof a small arena set up under NASA funding for Mars Roverresearch.A Pioneer robot equipped with a SICK laser rangeﬁnder was driven along an approximate straight line,gener-ating the raw data shown in Figure4b.The resulting mapgenerated with samples is depicted in Figure4c,with manually determined landmark locations marked bycircles.The robot’s estimates are indicated by x’s,illustrat-ing the high accuracy of the resulting maps.FastSLAM re-sulted in an average residual map error of8.3centimeters,when compared to the manually generated map.Unfortunately,the physical testbed does not allow for sys-tematic experiments regarding the scaling properties of theapproach.In extensive simulations,the number of land-marks was increased up to a total of50,000,which Fast-SLAM successfully mapped with as few as100particles.Here,the number of parameters in FastSLAM is approx-imately0.3%of that in the conventional EKF.Maps with50,000landmarks are entirely out of range for conventionalSLAM techniques,due to their enormous computationalcomplexity.Figure5shows example maps with smallernumbers of landmarks,for different maximum sensor rangesas indicated.The ellipses in Figure5visualize the residualuncertainty when integrated over all particles and Gaussians.In a set of experiments speciﬁcally aimed to elucidate thescaling properties of the approach,we evaluated the map androbot pose errors as a function of the number of landmarks,and the number of particles,respectively.The resultsare graphically depicted in Figure6.Figure6a illustratesthat an increase in the number of landmarks mildly re-duces the error in the map and the robot pose.This is be-cause the larger the number of landmarks,the smaller therobot pose error at any point in time.Increasing the numberof particles also bears a positive effect on the map andpose errors,as illustrated in Figure6b.In both diagrams,thebars correspond to95%conﬁdence intervals.Figure5:Maps and estimated robot path,generated using sensors with(a)large and(b)small perceptualﬁelds.The correct landmark locations are shown as dots,and the estimates as ellipses,whose sizes correspond to the residual uncertainty.ConclusionWe presented the FastSLAM algorithm,an efﬁcient new so-lution to the concurrent mapping and localization problem. This algorithm utilizes a Rao-Blackwellized representation of the posterior,integrating particleﬁlter and Kalmanﬁlter representations.Similar to Murphy’s work[12],FastSLAM is based on an inherent conditional independence property of the SLAM problem.However,Murphy’s approach main-tains maps using grid positions with discrete values,and therefore scales poorly with the size of the map.His ap-proach also did not deal with the data association problem, which does not arise in the grid-based setting.In FastSLAM,landmark estimates are efﬁciently repre-sented using tree structures.Updating the posterior requires time,where is the number of particles and the number of landmarks.This is in contrast to the complexity of the common Kalman-ﬁlter based ap-proach to SLAM.Experimental results illustrate that Fast-SLAM can build maps with orders of magnitude more land-marks than previous methods.They also demonstrate that under certain conditions,a small number of particles works well regardless of the number of landmarks. Acknowledgments We thank Kevin Murphy and Nando de Freitas for insightful discussions on this topic.This research was sponsored by DARPA’s MARS Program(Contract number N66001-01-C-6018)and the National Science Foundation(CA-REER grant number IIS-9876136and regular grant number IIS-9877033).We thank the Hertz Foundation for their support of Michael Montemerlo’s graduate research.Daphne Koller was supported by the Ofﬁce of Naval Research,Young Investigator (PECASE)grant N00014-99-1-0464.This work was done while Sebastian Thrun was visiting Stanford University.References[1] F.Dellaert,D.Fox,W.Burgard,and S.Thrun.Monte Carlolocalization for mobile robots.ICRA-99.[2]G.Dissanayake,P.Newman,S.Clark,H.F.Durrant-Whyte,and M.Csorba.An experimental and theoretical investigation into simultaneous localisation and map building(SLAM).Lecture Notes in Control and Information Sciences:Exper-imental Robotics VI,Springer,2000.[3]G.Dissanayake,P.Newman,S.Clark,H.F.Durrant-Whyte,and M.Csorba.A solution to the simultaneous localisation and map building(SLAM)problem.IEEE Transactions of Robotics and Automation,2001.[4] A.Doucet,J.F.G.de Freitas,and N.J.Gordon,editors.Se-quential Monte Carlo Methods In Practice.Springer,2001.(a)(b)Figure6:Accuracy of the FastSLAM algorithm as a function of (a)the number of landmarks,and(b)the number of particles .Large number of landmarks reduce the robot localization error, with little effect on the map error.Good results can be achieved with as few as100particles.[5]A Doucet,N.de Freitas,K.Murphy,and S.Russell.Rao-Blackwellised particleﬁltering for dynamic Bayesian net-works.UAI-2000.[6]J.Guivant and E.Nebot.Optimization of the simultaneouslocalization and map building algorithm for real time imple-mentation.IEEE Transaction of Robotic and Automation, May2001.[7] D.Kortenkamp,R.P.Bonasso,and R.Murphy,editors.AI-based Mobile Robots:Case studies of successful robot sys-tems,MIT Press,1998.[8]J.J.Leonard and H.J.S.Feder.A computationally efﬁcientmethod for large-scale concurrent mapping and localization.ISRR-99.[9] F.Lu and ios.Globally consistent range scan alignmentfor environment mapping.Autonomous Robots,4,1997. [10]N.Metropolis, A.W.Rosenbluth,M.N.Rosenbluth, A.H.Teller,and E.Teller.Equations of state calculations by fast computing machine.Journal of Chemical Physics,21,1953.[11] A.W.Moore.Very fast EM-based mixture model clusteringusing multiresolution kd-trees.NIPS-98.[12]K.Murphy.Bayesian map learning in dynamic environments.NIPS-99.[13]K.Murphy and S.Russell.Rao-blackwellized particleﬁl-tering for dynamic bayesian networks.In Sequential Monte Carlo Methods in Practice,Springer,2001.[14]P.Newman.On the Structure and Solution of the Simulta-neous Localisation and Map Building Problem.PhD thesis, Univ.of Sydney,2000.[15]R.Smith,M.Self,and P.Cheeseman.Estimating uncertainspatial relationships in robotics.In Autonomous Robot Vehni-cles,Springer,1990.[16] C.Thorpe and H.Durrant-Whyte.Field robots.ISRR-2001.[17]S.Thrun,D.Fox,and W.Burgard.A probabilistic approachto concurrent mapping and localization for mobile robots.Machine Learning,31,1998.。

化工单词大词典

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voltage withstand test; pressure test breakdown voltagebreakerbreakerbreaking strengthbrick layerbricking upbricklayerbridge, cranebrittle fracturebrittle materialbroken stone; crushed stone; macadam bronzebroombroom finishbrushing; applicationBS: British Standardbucket type strainerbucklebucklebuffer gasbuild up sequencebuilderbuildingbuildingbuilding general foremanbuilding linebuilding linebulbbulk cementbulk concretebulk modulusbulkhead barbulkhead,bulkhead, bank, embankment, bund bulkhead, partition plate bulkhead, retaining wall bulkhead, sealed partition wallbull gearbulldozerbulldozerbullgearbumpbumper postbundbundle, bunch, sheaf, refrain, constrain bundle, tie,buoyancy level transmitterburied serviceburied/back -filled on sitebursting discsbus couple circuit breakerbus ductbus ductbusbarbus-barbush hammerbushingbushingbushingbushingbutt jointbutt weldbutterfly valvebutyl rubberbypassby-pass lineby-productcabinetcable bundlecable clamp or strapcable glandcable glandcable trenchhigh tension power cable cable jointcable locatorcable lugcable pulling compound cable reelcable shoecable terminatorcable traycage laddercage of reinforcement caissoncaissoncalcareous claycalcareous sparcalcined limecalcined plastercalcium chloridecalcium-acrylate treatmentcalibrationcalibration runcaliductcambercanistercanopycanteencanteencantilevercanvascapacitor motorcapblockcappingCapping; blocking course capsule chambercar seal closedcar seal opencarbon arc weldingcarbon brushcarbon -dioxide arc welding carbon equivalentcarbon steelcarbon-zinc battery carborundum carborundum carborundumcardancarpentercarpet stripcarpet stripcarrier platecartridgecartridgecartridge heatercartridge operating fixing tools casingcasing assemblycast ironcast steelcast-in-place concrete catalyst tubecatalyst tubecatch potcatfacecatfacecathode dropcathode regioncathode spotcathodic protectioncatwalkcatwalkcatwalkcaulkcause & effect diagramcavitationcavitationcavity brick; hollow brick; tileceilingceilingcellulose type electrodecementcement linecement motarcenter linecenter pedestalcenter punch; drift pincentre to centrecentre to endcentre to surfacecentrifugal pumpceramic insulatorceramic nozzleceramic tilecertificatechainchain blockchain blockchain blockchain blockchain intermittent fillet weld chamferCheckered steel plateschamferchange order; modification notificationchannel（bar）charge engineerchargerCharpy impactcharred pilecheck valvecheck valvecheckingchemical admixturecherry pickerchief field engineerchill timechillerchin strapchipping hammerchipping hammerchiselCHIYODAchockchock logchokerchopperchopper circuitchopper controlchord platechroma I/OChro-molly; chrome nickle steel chutechutecindercindercindercindercircuit boardcircular electrodecircular filecircular saw circumference; perimeter circumferential lapcity layoutcivilcivil engineeringcivil general foremancladdingcladdingClamp; clipclamshell crane; grab craneclawbarclaycleaning agent; cleanser(solvent); detergen cleanlinesscleanoutclear glassclear spaceclearanceclearance; pitch; spacingcleatcleat; rungclerkclerkclevisclevisclipcloth masking tapecluttered work areaCMAA: Crane Manufacturers Association of America coal-tar epoxy paintcoarse aggregatecoatingcoating mixturecobblecobblecodecoefficientcold boxCold Boxcold drawn steel wirecold formedcold preservationcold springcolletcollet bodycolor codingcolumn packagecolumn platecolumn skirtcolumn， postcolumn; towercombination pliers; nippercombustible materialcombustible scrap and rubbish commissioningcommon labourcommutatorCompaction; tampingcompandercompandercompensating cable; extension wirecomplete penetrationcompletioncompolecomponentcomponentcompressed asbestos fibrecompressed gascompressed gas cylindercompression connectorcompression lugcompressive strengthcompressorcompressorcompressor buildingcompressor housecompressor traincomputer interface equipment & loopconcave fillet weldconcave root surface（suck-up）; root concavity concavityconcentricconcentric reducerconcreteconcreteconcrete aggregateconcrete batch/mix plantconcrete buggiesconcrete curingconcrete cylinder testconcrete finisherconcrete formworkconcrete placing/pouring concrete workercondensate potcondensate return piping condensate trapcondensercondenser discharge spot welding conductance level switch conductivityconductivity probeconductorconduitconduitconduit stub-upconduit; tremieconduletconduletcone type strainer configurationconfiguration parameter confined spaceconfined spaceconnect ; bondconnecting bridge;liason box connection kit; terminal connection; jointconnective weldconsecutiveconsistencyconsoleconsoleconsolidation of concrete constant temperature generator constructionconstruction devices construction equipment construction manager construction rubble construction schedule construction stake construction superintendent construction utilities consumableconsumable electrodecontacts of gaugecontaminationcontinuitycontinuous weldcontinuous weldingcontract awardcontraction jointcontractorcontracts managercontrol blockcontrol buildingcontrol building utility panel control roomcontrol valveconvectionconversational machine; walkie talkie convex fillet weldconvexitycooking facilitiescooling ratecooling tower basincooling water pipingcoordinatecoordinatecoordinatorcoped jointcopper shoecopper tubecore wirecore wirecorn ironcorner jointcorrectioncorrectionanticorrosioncorrosioncorrosion allowancecorrugated boardcorrugated steel pipecost & estimation engineercost allocationcost for man-hours being idledcost supervisorcountersunk boltcounter-sunk tapping screwcounterweightcounterweight supportcouplercouplingcouplingcouplingcouplingcoupling guardcovered electrodecovered projecting jointCPH(close pack hexagonal)CPU: central process unitCPVC= chlorinated polyvinyl chloridecrackcracking testcradle /lifting cagecraft supervisorcranecrane banksmancrane operatorcrane operators daily check-listcrane rail; crane girder;crane beam;overhead crane beam crane safety load indicator ,crank shaftcrankshaft bearingcratercratingcrawler cranecrawlingcrawling, creepcreepcreepagecreepagecreosotecrevice, crackcrimp type lugCrimp;compression connectioncrimping toolcritical flowcritical path methodcritical path methodcritical path methodcrocodile clipcross bracingcross bracing; cross stay; transverse strut cross ledgercross sectioncross shaped jointcrossheadcrossovercross-tiecross-tie, sleepercrosswalkCRSI= concrete reinforcing steel institute CRT: cathode ray tubecryogenic pumpcube testculvertculvert pipecurbcurb anglecurb stonecuringcuring compoundcurrent collectorcurrent limiting fusecurrent transformercurrent-limiting air-break circuit-breaker cursor keyscurvaturecushion course; matcushion headcushion pilecushion pilecustomizedcut backcut-in setcutoffcutoffcut-off wheelcutoutcutoutcutting disccutting ringcutting torch gogglescylindercylinderDALS（double-acting limited-switch）damagedamage to the coatingdampening &linearity adjustment damper platedanger tagDAR(dielectric absorption ratio) test dark glassdata packagedavitDCENDCEPDCS: distributed control systemdead loaddeadweight testerdeaeratordebrisdebrisdeburdecibeldecorationdeep penetration weldingdefault valuesdefectdeflectiondeformed bardeformed; distorteddegreasedehumidifierdeleterious substancedelivered as bulk materialsdeliverydemisterdemolish; demolition; move off deoxidiserdeposited metaldeposition ratederrickderrickderrickderrickdesiccantdesign mixdestructive test desuperheater detachabilitydetaildetectordetector background noise detergent solution developerdeviationdeviation indictordewdew pointdew pointdew pointDFT= dry film thickness dial gagediameter inchdiameter of electrode diaphragm seal diaphragm valve diaphragm valvedie grinderdielectric heaterdielectric resistancediesel fueldif primary elements differential manometer differential pressure gauge diffusible hydrogen diffusion weldingdigital I/Odip switchdip switchdirect labordirection of induced voltage direction of welding directional signsdisc like crack dispatcherdisplacementdisplacement(with air)displacer; float drumdistance between wiredistinguishable color difference distribution drumdistributordistributordomestic sewage; sanitory sewagedoor stopdoor stopDOT= Department of Transportation DOT= Department of Treasurydouble barrel type lugdouble beading jointdouble corner beadingdouble glazed windowdouble groovedouble sleevedouble strong; extra strongdowel; pindownspout（down pipe)downspoutdownstreamdownward welding in the inclined position DP transmitterdraftsmandraindrain funnel ; floor draindrain pocketdrain; sewer; culvertdrawingdrierdriftdrift pindrilldrill bitdrilling machinedrip legdrive shaftdriverdrop-indicator relaydropping pointdrumdrumdry coating thicknessdry film gaugedry gas sealdrying equipmentdrying equipmentdrying timedual element fusedummy bearingdummy endboxdummy flangedummy headerdummy supportdummy welddump truckdump truckdumped in unauthorized area dumperdust maskdust pandusttightDWSI(double wall single image) dye penetrantdye-penetrant examination dynamic characteristic of arc ear muffear plugear plugearthearth clampearth leakage circuit breaker earth workerearthingearthworkeccentriceccentric reducereccentricityedge distanceedge jointedge weldeffective powereffective throatEIA: electronic instrument association ejector/educterelastomericelastomericelbowelbow capelectric buildingelectric drillelectric fusion weldedelectric fusion weldedelectric hammerelectric roomelectric shockelectric tracingelectricalelectrical wiringelectrical work permitelectricianelectrodeelectrode contact surfaceelectrode dryer/quiverelectrode for vertical down welding electrode holderelectrode holderelectrode pick-upelectrode pressureelectrode skidelectrode travelelectro-gas weldingelectron beam weldingelectronic recorder electropneumatic positionerelectro-slag weldingelementary errorelevated zero setting ; span suppression elevationellelongated indicationelongationembedded itemembrittlementemergency access-routeemergency evacuation drillemergency exitemergency procedureemergency shutoff devicesemulsifieremulsion paintenamelled cable（wire）end coronaend to endendwallenergizationenergize/isolate electrical suppliesenergy inputengineerengineerengineeringentry permit for confined spaceentry road, access roadepoxy resinEPROM: electrically programmable read only memory equal percentage flow characteristicsequipmentequivalent line sizeerection openingerosionescape route to designated assembly pointESD: emergency shutdownessential balmevacuation planevaluationevaporatoreveryday penlightexaminationexcavationexcess penetrationexcessive penetrationexcessive thinningexchangerexchangerexciterexecutive officerexhaust gasexhaust headexisting barexisting plant areasexothermic connection expansion joint, tissue compensator explosion weldingexposed slagextension leadextension to scheduleextensive repairexternal steam tracingeye bolteye bolteye nuteye wash kiteye-holefabricated pipe bendsfabricationfabrication tolerance fabrication; manufacture fabricatorface of weldface shieldfacilityfail-safefall protectionfall protectionfall-of-potentialfalse ceilingfalse floor; access floorfanfanfastenerfaucetfaucetfaying surfaceFCAW= flux-cored arc welding FCC(face center cubicle)feed panelfeeler（=feeler gage)felt ringfemale adapterfemale connectorfemale rotorfenced offfencingferriteferruleferrule type fuseFF（flow fraction）FFD:Focalspot to Film Distance fibre ropefibre ropeFID: flame ionization detector field discharge resistorfield engineerfield paintingfield paintingfield resident managerfield weldfield weldfield weldingfield(=stator) coilsfield; jobsitefill passfillerfiller metalfiller panelfiller; putty; stopping; surfacer fillet weldfillet weld in normal shearfillet weld in parallel shearfillet weld sizefillet weldingfillet welding in the flat position film markfilm type inclusionfilter housingfilter maskfilter pressure reducing regulator Filter; strainerfin; flash; burrfinal accountingfinal alignmentfinenessfinishfinish gradefinish paintfinishing workfinned heaterfire alarmfire armsfire brigadefire clothfire drillfire extinguisherfire hazards/scrap pilefire hydrantfire protection and prevention fire resistance clothingfire wardensfire waterfired corner tube boilerfire-water mainsfirst aid (and rescue) kits first aid stationfish eyefit upfitters' glovesfittingsfixed carbon resistorfixed fire equipmentfixed fire systemflame arresterflame cuttingflammable and toxic flammable liquid flammable materialflangeflange adapterflange capflange plateflange weldingflare stackflare tube fittingflared endflared fittingflash butt weldingflash pointflash timeflashingflashoverflatflat barflat faceflat metallic gasketflat position weldingflexi tubeflexible bush manchet flexible hoseflexible hosefloatfloated finishfloatingflogging spannerflood lightfloorfloorfloor slabflue duct; stack ductfluidity of the slag fluorescentflush valveflush-finished overlapfluxflux-cored wirefly ashfly ashFNSH: finishingfoam glassfog sprayfooting; skidforehand weldingforemanforemanforeman (all crafts)forge timeforged steelfork liftfork wrenchesfork-indent-type lugform factorform removal/stripping/releaseForm; formwork; shuttering; templateform-fit transformerfoundation; plinthframefree of dirtfreon (CCL2F2)freon (ccl2f2)friction weldingfringe benefitfront line supervisorFTC（field termination cabinet）fuel skidfuel skidfull back pressure; reseating pressure; tight reset pressure full couplingfull fusionfull key couplingfull scalefullgraphic annunciatorfull-wave bridge rectifierfurnacefurnacefurnace boxfurnace boxfusefused fluxfusion line; bond linefusion weldingGA （general arrangement）gain factorgalvanizedgalvanized steelgalvanized surface repairgas chromatographgas cuttinggas cylindergas detectorgas heated swivel burnersgas manometergas poregas shielded arc weldinggas torchgaseous impurities; worm holes; blowhole gasketgate valveGCGCCgear boxgelatingelatingeneratorgeotechnical engineer, civil engineer girdergirtgirtgirth weldgirth weldinggive-way pointsgland packingglass fiberglass panel heaterglass woolglazed tileglobe valveglobular transferglobuleglueGMAW= Gas metal arc weldinggo cartGO-HDS: gas oil hydrogen desulphurisation gooseneck faucetgradation; gradinggradegraded paper insulationgraingrain diametergratinggratingsgravelgravity coefficient of coatinggravity weldinggreasegreeninggreenbelt; landscaping areagrinder switch contactgrinding discgroove facegross discontinuities gross weightground busground cableground fault interrupter ground girdground guideground penetration ground rodgrounding grid grounding; earthing groutingguardguard houseguard railguest houseguide pileguide supportguide vanegully drain; sewerguttergypsum boardH.F. resistance welding hack sawhack saw blade hacksawhair/line crackhalf couplinghalf key couplinghalf round filehammer drillhammer with a loose head hand gloveshand holehand over to piping hand railhand sawhand spikehand toolhand toolshand vicehand wheelhand wire brushinghandlinghandlinghandoverhandshake i/o controlhangerhard hat; safety helmethard materialhard pumphardenerhat-stickershauling ropehazardous wasteH-beamHDPE: high-density polyethylene head counting; roll callheaderheaderheaderheaderheaderheat boiler/electric heaterheat exchange packageheat No.heat tracingheat treatmentheat-affected zoneheaterheavy dutyheld waterhelium arc weldinghelperhex head bolthex meshhexagonhidden work; embeddingshigh windhigh work/ elevated work highlighterhighwayhighway isolation boxhinge pipe vicehoist, trolleyhoist; winchhoisting winchholdholding tankholidayholiday testholiday testhook-up （diagram）horizontalhorizontal deviationhorizontal position welding horizontal pumphorseplayhose connectionhose connection; hose splicerhose stationhost linkhot and neutral wirehot wellhot workhot work permithot work permithot-cathode fluorescent lamphot-dip galvanizedhot-extruded shape( angle, tee, channel) hot-formedhot-rolledhousehold bleachHVAC:heating，ventilating and aircon hydraulic cementhydraulic compression toolhydraulic oil linehydraulic oil pumphydraulic pumphydrotestinghysteresishysteresis coefficientHigh strength hex head boltI beamI.D.card。

calibration

标准件的追溯性
Standard Traceability
Metrology Equipment & tools
Standard wafer
Calibration Lab
Vendor
VLSI(USA)
校准之标准件
Calibration Standards
Alpha step height Dektak250 Standard wafer Filmmetrics F50 SiO2 on Si Standard wafer 4PPsurface resistance RT-70V standard BST DAGE4000 standard weight Spectrometer S-3100T Standard wafer polished both sides
测量设备标准件的管理程序
Metrology Equipment Standard Management Procedure
*****Copyright and Business Secret belong to Elec-Tech Photoelectric Technology（Dalian). Don’t Copy Without Permission.*****
校准定义：
在规定条件下，为确定测量仪器仪表或者测量系统所指示的量值，或实物量具或参考物质所代表的量值与对应的标准件所复现的量值之间关系的一组操作。通常人们是按照明确的，由文件规定的步骤来进行的一组操作，用以把一台仪器的已知值，通过比它更为精确的仪器或者标准进行测量后，并加以比较，从而探测和报告被测量仪器的误差，或者通过调节来消除被测量仪器误差的一组过程。标准件（Standard)：可追溯到国家标准，国际标准或者厂商的测量标准件，用来对测量设备&仪器等进行周期测量的量具。

Mettler Toledo 产品说明书.pdf_1701918296.77462

零陵渔鼓的发展历程与传承现状研究零陵渔鼓是湖南省衡阳市零陵区的一种民间传统音乐表演形式，也是中国非物质文化遗产之一。

它以其独特的表演形式和浓郁的地方特色，成为零陵地区乃至湖南省乃至全国的一张文化名片。

以下是关于零陵渔鼓的发展历程与传承现状的研究。

零陵渔鼓起源于中国南方的乡村，其历史可以追溯到明代末年。

据传，明朝嘉靖年间，衡阳城东九洲渡口的渔民在打渔之余，用鼓琴演奏民间音乐，吸引了不少群众观看。

渐渐地，渔民们开始在自家门口演奏，形成了一种独特的音乐文化形式，即零陵渔鼓。

在清代，零陵渔鼓开始流传至广大的乡村地区，并逐渐成为乡村民众的娱乐活动。

当时，零陵渔鼓主要是由鼓手和琴师组成的，他们通过鼓、琴等乐器演奏各式各样的民间曲目，如《渔家傲》、《大刀进行曲》等，吸引了很多观众。

在20世纪50年代后，随着中国南方经济的发展和社会的变革，零陵渔鼓逐渐衰落。

社会对零陵渔鼓的传承和发展缺乏重视，许多年轻人也对这种传统艺术形式失去了兴趣。

由于一些艺术家和文化爱好者的努力，零陵渔鼓得以保留下来，并在近年来得到了一定的发展。

目前，零陵渔鼓的传承现状较为艰难，面临着许多困难和挑战。

由于现代城市化的发展，农村地区人口的减少和乡村文化的衰退，零陵渔鼓的传承环境变得十分不利。

年轻人对零陵渔鼓的兴趣不高，很少有人愿意学习和传承这一传统文化艺术形式。

零陵渔鼓面临的另一个挑战是缺乏专业人才。

由于这一艺术形式的特殊性和学习难度，需要长期的专业培训和丰富的舞台经验。

目前专门从事零陵渔鼓的艺术家寥寥无几，传统的技艺和经验也很难得到有效传承。

为了解决这些问题，一些相关机构和爱好者采取了一系列的措施来推动零陵渔鼓的传承与发展。

他们积极组织零陵渔鼓的演出和表演活动，通过精彩的演出吸引观众，提高大众对零陵渔鼓的认知和兴趣。

他们加强了对青少年的培训和教育工作，引导他们对零陵渔鼓等民间艺术形式的兴趣，同时提供培训课程和教材，以提高学习的效果。

他们还积极寻找和录制零陵渔鼓的音乐和视频资料，建立了相应的档案和数据库，为研究和保护零陵渔鼓提供了重要的参考。

基于关节耦合补偿提高机器人绝对定位精度

《装备制造技术）2020年第10期方法与技术基于关节耦合补偿提高机器人绝对定位精度陈琳,刘华辉，马忠睿,梁旭斌，林志,潘海鸿（广西大学机械工程学院/实训中心，南宁530004）摘要:针对六自由度工业机器人设计中所产生的耦合运动，将会对机器人末端绝对定位精度产生影响。

为减少甚至消除关节耦合对机器人末端精度的影响，提出通过激光跟踪仪实现机器人关节耦合补偿的方法。

该方法使用激光跟踪仪确定耦合的关节，并测量出关节耦合的角度，然后计算出耦合比，最后将耦合比补偿到对应关节。

通过实验测试关节耦合比补偿后关节耦合角度比补偿前明显下降，且机器人的X,Y,Z方向位置误差和PE误差明显减小，平均绝对定位精度和动态精度（TCP测试）均有提升。

实验结果表明，提出的方法能够解决实际工程中机器人关节耦合问题。

关键词：工业机器人；关节耦合；绝对定位精度;激光跟踪仪中图分类号:TG156文献标识码：A文章编号:1672-545X（2020）10-0001-030引言目前,大多数六自由度工业机器人的重复定位精度在0.1mm以上［1-2］，可以满足电子产品制造、汽车生产、焊接等工业应用的基本要求。

然而，随着技术的发展，特别是在航空航天和精密制造领域，机器人的生产需求要求机器人具有较高的绝对定位精度［3-5］o六自由度工业机器人的结构设计中，为增加末端执行器的灵活性和快速响应性，需减轻大小臂和手腕部分的重量，一般是将臂关节和腕关节的驱动电机向腰部（基座）方向移动。

这导致部分关节的运动传递线路加长，各关节的运动不可避免地相互影响，即产生耦合运动（称为单向耦合）机器人关节耦合会导致关节角运动不到位，是影响机器人末端绝对定位精度误差因素［6-7］之一。

目前国内外关于机器人关节耦合运动对机器人绝对定位精度影响的研究较少。

韩建达冈等分析机器人关节加速度反馈解耦控制的开环模型，提出闭环控制策略的设计准则o林义忠［9］等分析耦合运动产生的原因，探讨耦合运动造成的驱动电机的功率冗余现象。

利用实测重力垂直梯度反演长白山地区一剖面的深部构造郇恒飞

第31卷第4期2012年12月世界地质GLOBAL GEOLOGYVol.31No.4Dec.2012文章编号：1004—5589（2012）04—0791—06利用实测重力垂直梯度反演长白山地区一剖面的深部构造郇恒飞，吴燕冈，管彦武，杨长保吉林大学地球探测科学与技术学院，长春130026摘要:针对重力梯度高分辨率的特点，利用在长白山地区实测的重力垂直梯度数据，采用梯度空间参量图反演其深部构造。

台阶模型试验表明:重力梯度空间参量图能给出构造倾角和倾面的信息，结合重力梯度剖面和梯度空间参量图可以构建出地下构造的几何模型，进而对一些复杂构造进行解释。

通过对比实测布格重力异常和实测重力梯度异常，重力梯度比重力异常的分辨率更高;将梯度法应用到实测重力梯度数据的处理中，结果表明:该方法对确定密度变化界面的水平位置和深度具有非常好的效果。

关键词:重力梯度;梯度空间参量图;长白山;实测梯度中图分类号:P 631.1.23文献标识码:Adoi :10.3969/j.issn.1004-5589.2012.04.021收稿日期：2012-06-21；改回日期：2012-08-08基金项目：国家自然科学基金重点项目（40930314）与吉林大学基本科研业务费（450060445194）联合资助．通讯作者：吴燕冈（1954--），女，教授，主要从事应用地球物理方法技术研究．E-mail ：yangang_wu341@ Deep structure iversion by measurement of verhical gradient of gravityfor a profile of Changbai Mountain areaHUAN Heng-fei ，WU Yan-gang ，GUAN Yan-wu ，YANG Chang-baoCollege of Geo-exploration Science and Technology ，Jilin University ，Changchun 130026，ChinaAbstract ：In connection with the characteristics of high-resolution in gravity gradient ，we used the data of measured vertical gravity gradient in Changbai Mountain area to inverse its deep structure by using gradient space plot．The step models prove that the gradient space plots can give the information of the structural dip and pour sur-face．Combined with gravity gradient profile ，we can build a geometric model of the subsurface structure ，and then explaine some of the complex structure．Based on the measured Bouguer gravity anomaly and the measured gravity gradient anomaly contrast ，the gravity gradient has higher resolution than gravity anomaly．When the gradient meth-od is applied in the measured gravity gradient data processing ，the results show that the method to determine the density changes in the level of the interface position and depth has good effect．Key words ：gravity gradient ；gradient space plot ；Changbai Mountain ；measured gradient0引言重力梯度是重力的变化率，具有比重力异常更高的分辨率［1］。

【经典外文翻译】--底土的土壤结构和饱和导水率—-毕业论文设计

英文原文：Low-cost programmable pulse generator for particle telescopecalibrationAbstractIn this paper we present a new calibration system for particle telescopes including multi pulse generator and digital controller. The calibration system generates synchronized pulses of variable height for every detector channel on the telescope. The control system is based on a commercial microcontroller linked to a personal computer through an RS-232 bidirectional line. The aim of the device is to perform laboratory calibration of multi-detector telescopes prior to calibration at accelerator. This task includes evaluation of linearity and resolution of each detector channel, as well as coincidence logic. The heights of the pulses sent to the detectors are obtained by Monte Carlo simulation of telescope response to a particle flux of any desired geometry and composition. Elsevier Science B.V. All rights reserved.To assure a correct interpretation of data obtained with scientific instruments onboard satellites, as well as to compare these data with those of similar instruments, a thorough pre-flight calibration is required. For solar and cosmic ray particle telescopes, this calibration is usually carried out in two steps: first, a calibration of each individual detector using radioactive sources and standard nuclear instrumentation (NIM or CAMAC modules),following by a final test of the whole telescope performed in a particle accelerator site. The success of calibration on accelerator requires that, prior to the experiences, all detectors and electronics parameter (polarization voltages, amplifier gains and shaping times, thresholds, etc.) have nearly definitive values. Here we propose a cheap and simple pre-calibration procedure based on a new system that we have called Programmable Pulse Generator (PPG). The PPG developed in our laboratory has been designed for a specific instrument, a four-detector cosmic ray telescope, but it can easily be modified for similar experiments.The standard calibration procedure for individual detectors and their electronic chains consists of introducing pulses of known amplitudes coming from a pulse generator, together with the pulses released in the detector by particles coming from a radioactive source. However, these standard pulse generators do present severallimitations: The pulse amplitude must be set manually. Thus, to generate the pulses that different particles with different energies would release on the detectors, it is necessary to change the pulse heights every time.Standard pulse generators only provide one output signal, so either several modules are needed to calibrate a complete telescope, or it is necessary to split the single output in order to get several signals. It is difficult to check the coincidence logic because the four signals are not independent.To overcome these difficulties, pulse generators of programmable amplitude and rate have been proposed. Abdel-Aal [1]presented a programmable random pulse generator where the height and separation of individual pulses are controlled by software.But in his scheme the pulses are released directly from a digital-to-analog converter(DAC),thus having the temporal characteristics of the DAC output. Our purpose is to generate variable height analog pulses with similar shape to that released by nuclear detectors.The low-cost PPG presented here is intended to introduce every detector channel ，the pulses released by any particle flux supposed to be encountered by the instrument on real experiments (in our case, on outer space environment). The proposed pre-calibration scheme is sketched in the diagram of Fig 1. For a big number of simulated events, the energy signals released at the different detectors of the telescope are stored on a personal computer (PC). For each individual event, the energy signal data are sent through a bidirectional RS-232-C line to the PPG, which transforms the results of the simulation into real pulses and sends them to the real instrument.Fig 12 PPG descriptionThe design of the PPG is divided into two functional modules: digital electronics and analog electronics, whose block diagrams are enclosed in dashed boxes shown inFig2. The data arriving at the digital module from the PC are sent to 12 bit DAC. The DAC output voltages are transformed in the analog module into suitable pulses, ready to be introduced into the test input of the related detector channel of the telescope.Analog and digital modules are described with some detail in Sections 2.1 and2.2. In Section 2.3 we describe some noise problems related with the microcontroller,and the way we found to solve them.2.1 Analog moduleThis module must be capable of producing signal pulses similar to those generated in the detectors by the passage of energetic charged particles, whose shape can be described by the following function:()V t exp exp .1/R F R F A t t ττττ⎡⎤⎛⎫⎛⎫=---⎢⎥ ⎪ ⎪-⎝⎭⎝⎭⎣⎦(1) The relevant signal parameters are the pulse height or amplitude A, the rise time R τ and the fall time F τ (here expressed as 1/e times rather than 10-90% times).Using semiconductor detectors, typical values for R τ and F τ are approximately 5ns and 10 us, respectively.Our particular telescope has four detectors, therefore four almost simultaneous pulses with different amplitudes 14A A -have to be generated for each simulated event. These amplitudes are sent by the digital module to the analog module, together with a start pulse (see Fig 2). The communication is performed through a coupler circuit for isolation purposes. The start signal is sent to a reference pulse generator, which generates a pulse of constant amplitude, rise and fall times. One of the inputs of each multiplier is this reference pulse, and the other is one of the DAC amplitude signals. Thus, every multiplier acts as a modulator: when the reference pulse arrives,the multiplier generates a similar pulse whose amplitude is the respective voltage given by the digital module.The reference pulse generator is the most critical element in the system, because any noise in the reference pulse will be present (and not independently) in each of the output signals. The core of this element is the circuit shown in Fig 3. Before a start pulse arrives to the reference pulse generator, the capacitor 1C is charged atvoltage 15ref CV A V +, ultra-precision, guaranteed long-term drift voltage reference has been used for this purpose (MAX677BCPP). Once the capacitor 1C present stablevoltage and a start pulse is generated, this capacitor is connected to 1R switching therelay 1K . In order to avoid the characteristic glitches of the mechanic relays, amercury relay has been used. Mikhailov [2]has pointed out recently the limited pulse rate (~100 pps) achievable with mercury relays, but we focuses on modulating the pulse amplitude rather than reaching a high pulse rate. When 1C is connected to 1R , the equations describing the evolution of the circuit of Fig3 are the following:()112121110R i R i i i dt C +++=⎰ ()2122210.R i i i dt C ++=⎰ (2) The solution of this linear system with the conditions ()10ref v V = and ()200v = gives an output pulse ()2v t with the functional form (1) and amplitude ref V . Thoughthe rise and fall times depend on resistor and capacitor values through a complicated algebraic expression, for 12C C (condition fulfilled here) the following approximate expressions hold:12212R R R C R R τ≅+ ()121F R R C τ≅+ (3)The values and characteristics of capacitors, resistors and reference voltage are given in Table 1; for these values 5R τ≅ns and 10F τ≅ s μ. The shape, rise and falltime of the reference pulse are shown in Fig 4 .Fig 4. Oscilloscope images of the reference pulse rise (left) and fall (right) flanges. The quoted values of rise and fall time refer to 10-90%of the amplitude. The values of R τ and R τ in the text refer to 1/e of the amplitude.The reference pulse generator must present very good time stability against temperature and power supply variations, as well as noise immunity. In order to meet these restrictions, special components have been used, and the reference pulse generator has been placed inside a Faraday cup with the aim of isolating it from the rest of the system.In order to respond to the high-frequency components of the reference pulse (rise time~5 ns), the multiplier AD834, which presents 4 ns transition time, has been chosen.The output range provided by the multipliers 0-1000 mV, and the output signals of every detector channel are digitized by 0-4096 bit ADC. Thus, every multiplier output must be adjusted to cover the corresponding ADC range. This requirement is fulfilled by suitable pi attenuators, that match the PPG output and test input characteristic impedances, while adapting the output and input ranges. These attenuators can be easily changed to match any detector channel.中文翻译：底土的土壤结构和饱和导水率摘要饱和导水率sat K ，是在从耕作层和底土中采集来的土壤样品上衡量的。

目标红外辐射特性测量定标方法研究

目标红外辐射特性测量定标方法研究樊宏杰;刘艳芳;刘连伟;姚梅;许振领;杨淼淼【摘要】阐述了定标工作在目标红外辐射特性测量中的重要作用。

分别就调焦类成像设备和非调焦类成像设备的定标方法进行了理论分析，针对不同定标方法的优缺点进行了说明，定标时通常采用0米定标，方便且可同时进行所有像元定标。

对目标特性测量时定标温度的选择作了分析，得出结论：定标间隔不变时，定标误差随定标温度呈“W”型规律变化，当定标温度分布于测量温度两侧时，误差有限，因此定标温度通常选择在目标等效黑体温度两侧，且定标温度间隔越小辐射特性测量精度越高。

%Calibration plays an important role in infrared characteristic measurement.Calibration method of fixed-focus imaging sensor and adjustable focus imaging sensor are theoretically analyzed.Merits and demerits of different calibra-tion methods are introduced.Zero meter calibration method is usually selected,it is convenient and can calibrate all pixels.The selection of calibration temperature is analyzed in target IR characteristic measurement,analysis results show that:when calibration temperature interval is constant,the calibration error changes along"W"shape with cali-bration temperature;The calibration error is limited when calibration temperature distributes both sides of measurement temperature,so calibration temperature is selected on both sides of equivalent blackbody temperature,and calibration error is smaller when calibration temperature interval is smaller.【期刊名称】《激光与红外》【年(卷),期】2014(000)005【总页数】6页(P516-521)【关键词】红外辐射特性;辐射特性测量;定标【作者】樊宏杰;刘艳芳;刘连伟;姚梅;许振领;杨淼淼【作者单位】解放军63892部队，河南洛阳471003;解放军63892部队，河南洛阳471003;解放军63892部队，河南洛阳471003;解放军63892部队，河南洛阳471003;解放军63892部队，河南洛阳471003;解放军63892部队，河南洛阳471003【正文语种】中文【中图分类】TN21要研究目标/背景的辐射特性，需要进行大量的测量工作，通过测量可实现以下2个方面的目的: (1)可研究目标和背景的辐射分布、检验理论模型的计算精度，促进模型改进，提高模型的可信度; (2)可以研究目标与背景辐射特征之间的关系，考查目标背景的对比度。

全球及局部海洋扰动重力反演的快速解析方法

全球及局部海洋扰动重力反演的快速解析方法佚名【摘要】In order to solve the problem of deriving the disturbing gravity from satellite altimetry data,the analytical formula of disturbing gravity computed from geoid and vertical deflection are derived.The analytical formula can be used to get global ocean disturbing gravity by using altimetry data.Considering the existing achievements,the two improved quick computation methods which are respectively according to the global and local area are also get based on the one dimensional FFT algorithm.The quick computa-tion methods can get the same results asthe analytical computation and improve the computation speed of 20 times.The precise,quick computation methods can avoid the problem of aliasing and edge effects and have the flexible application.The2.5′resolution of geoid and vertical deflection derived from EGM2008 model are used to compute the global and local ocean disturbing gravity.The results show that the difference between two method is about 0.8×10-5 m/s2,so the disturbing gravity respectively derived from geoid and vertical deflection are consistent.Considering the actual situation,the disturbing gravity derived from vertical deflection sti l l has some advantages.%从经典边值问题理论及球谐函数理论出发，在空域推导获得了由大地水准面高以及垂线偏差计算扰动重力的解析计算公式，为利用卫星测高数据反演海洋扰动重力提供了理论基础.针对全球海洋区域和局部海洋区域的扰动重力反演，在前人已有工作基础上，提出了改进的基于一维 FFT 的精确快速算法，保证了计算结果与原解析方法完全一致，且计算速度提高约20倍.该算法在提高计算效率的同时避免了由于引入 FFT而产生的混叠、边缘效应问题，而且对观测数据的序列长度没有硬性要求，使得应用更加灵活.利用 EGM2008地球重力场模型分别生成了2．5′分辨率大地水准面高数据和垂线偏差数据，按照本文提出的改进方法(采用全球积分计算)分别反演获得了全球及局部海洋区域的扰动重力.经比较分析，由大地水准面和垂线偏差分别反演获得的扰动重力其差异在0．8×10－5 m/s2以内，这说明两种反演方法是基本一致的，但在数据包含系统误差的情况下，由垂线偏差反演扰动重力具有一定优势.【期刊名称】《测绘学报》【年(卷),期】2015(000)008【总页数】6页(P827-832)【关键词】大地测量;扰动重力;大地水准面;垂线偏差;快速算法【正文语种】中文【中图分类】P2231 引言传统的海洋重力场一般是指由各种观测手段获得的重力异常，随着空间大地测量学及物理大地测量学的发展，扰动重力较重力异常表现出更多优势。

Pipette Calibration Solutions ISO8655 Compliant 制品

Calibrating Pipettes P i p e t t e C a l i b r a t i o n2P i p e t t e C a l i b r a t i o nEfficient Calibration of Pipettes for Fast & Traceable ResultsWhether you’re an accredited in-house lab or service provider, pipettecalibrations must be performed accurately, efficiently and must fulfill regu-latory guidelines such as ISO8655.METTLER TOLEDO offers comprehensive solutions for pipette calibration.Our reputation for weighing, pipettes and process-oriented software, combined with our expertise of over 20 METTLER TOLDEO calibration labs worldwide results in a user-oriented, efficient and compliant calibration portfolio like no other manufacturer.of the pipette after calibration and adjustment .Calibration Cert iﬁc ateIssue a calibration cert iﬁcate as proof that the pipette has been tested and adjusted.The Calibration ProcessMETTLER TOLEDO's weighing reputation combined with process oriented software, results in an efficient, reliable and compliant pipette calibration process according to ISO8655.3/pipcalISO 8655 compliantISO 17025 accredited labs cali-brate according to ISO8655 for volumetric devices. Our solutions are fully compliant from the balance for measurements to software, with reports for a fast and secure process.4Fast Micro Pipette Calibration Down to 1 μl VolumesCalibration of smallest volumes down to 1 μl are a challenge to do accu -rately and efficiently. The XPE26PC was designed by specialists and is the benchmark in many calibration laboratories world-wide.The micro balance weighing cell, combined with the motion sensor lid and large evaporation trap enable a focused workflow with accurate results right first time. Additional functions such as the StatusLight, the large waste container and optional sensors support an efficient calib-ration process with trusted results.P i p e t t e C a l i b r a t i o nFast & efficient Continuous calibration Unique durable designThe motion sensor lid and large 80 ml evaporation trap of the XPE26PC ensure fewer handling steps and fast, stable results even when calibrating micro pipettes down to 1 μl according to ISO 8655.The large 10 ml container allows many calibrations in a largerange from 1 μl or higher without interruption. A suction pump is included to easily empty the waste water container.Thanks to the unique hanging weighing pan design, the bottom plate is completely sealed and prevents water or fluids dripping into the balance mechanics and weighing cell, for a durable andconsistent lifetime performance.5/pipcalValid results Improve ergonomics Stability increases speedThe built-in StatusLight™ uses color to indicate intuitively the status of the balance. The green light indicates clearly that the balance is ready for you to begin your next calibration, so you can be sure your results will be valid.Optimize your process with an optional motion sensor which can be placed freely on the bench for touchless and conta-mination-free operation of the balance.An optional dual framed weig-hing table reduces to a minimum any user or environmental vibra-tions, substantially speeding up measurement times. With this complete solution, pipette calib-ration is faster than ever.6Calibrate from 20 μl to 10 ml on One BalanceThe XPE analytical balances with professional evaporation traps make it possible to calibrate volumes from 20 μl to 10 ml with just one balance, according to ISO8655 quickly and efficiently.In addition, the unique design with hanging pan and detachable draft shield facilitate optimal working ergonomics and easy cleaning, without the risk of fluids or dirt entering the weighing cell.P i p e t t e C a l i b r a t i o nFrom 2 μl to 2000 μl From 2 ml to 10 ml Simply adapt to your needsGlass evaporation traps enable fast calibrations from 20 microli-ters to 2 milliliters, thanks to the stable setup, good visibility and independent waste container.Simply switch the trap to cali-brate volumes from 2 to 10milliliters. The metal 100 milliliter evaporation container is easily exchanged on the XPE analytical balance.The terminal, motion sensor doors and draft shield can simply be detached anytime to improve access and ergonomicsor just to make cleaning easier.7/pipcalUnique construction Easy Leveling Training DayThanks to the unique hanging waste container, the base is completely sealed which pre-vents dust, fluids and powder from entering the weighing cell ensuring a lasting performance of your balance.The LevelGuide™ provides you with a warning when the XPE balance is not leveled. Full inst-ructions and a graphical leveling bubble are shown on the touch-screen so you can proceed your calibration within e the built-in training module and Pipette Check to train users or check pipettes independently of the system. Users are guided through the process and their individual performance can betracked.8Efficient and Compliant Calibrations with Calibry SoftwareCalibration task planning, guided calibration processes, collecting data, generating reports and being compliant at the same time, these are the benefits of using Calibry Software – effiency personified.Calibry was developed with calibration professionals, who know what is important and necessary in accredited calibration laboratories. With over decades of experience and continuous improvements, Calibry is an established benchmark for many calibration laboratories all over the world.P i p e t t e C a l i b r a t i o nGuided process Complaint and traceable Clever SolutionsCalibry software supports all steps of the calibration process. The large cockpit screen during calibration ensures an easy and secure calibration process of all pipettes.Calibry software saves all calib-ration data in a secure SQL data-base, and ensures compliance with ISO8655 regulations and reports.RFID Pipettes from Rainin need only to be scanned to initiate a task overview or to start a calib-ration directly.9Customized reports 21CFR Part 11 supportive Software validationISO8655 compliant and compre-hensive reports can be generated and adapted to specific needs. If required all data can be exported and used to generate custom specific reports as well.For regulated areas Calibry contains many FDA 21 CFR Part 11supportive features, such as user management, report release, method change history and audit trail.The software validation binder saves valueable time for prepa-ration and validation process. Due to the prefilled information and templates, software releases are completed quickly and more accurately./pipcal10Pipette Calibration Systems Technical InformationCalibration SystemXPE26PCCalibration SystemXPE205Calibration range according ISO8655≥ 1µL – 1'000µL > 10 µL – 10'000 µLBalance type XPE26PC XPE205Evaporation trapBuilt-in 80 mlOptional: 20 ml - 11140043Optional:100 ml - 11138440Motion Sensor Lid opening •-Motion Sensor Draft Shield doors-•Hanging Pan design with closed bottom plate for safe cleaning ••Detachable draft shield -•Detachable terminal ••LevelControl ••StatusLight••ProFact internal Temp. & Time adjustment ••Extra Motion Sensor and/or Footswitch Light Barrier - 11140029ErgoSens - 11132601Footswitch - 11106741Footswitch - 11106741Waste water suction pump •Optional 11138268CarePac Test Weight Set Optional - 11123006Optional - 11123008Calibry Software compatability ••Weighing tableOptional - 11138041Optional - 11138042• included / - not applicableBuilt your own Calibration System that suits your needs.A Calibration System is based on an XPE balance with optional accessories to improve your calibration process. Every balance can be connected to Calibry Software for secure data capture.T e c h n i c a l S p e c i f i c a t i o ns11Model XPE26PC XPE205Order no.3010590130087653Typical Pipette Calibration Range* 1 - 200 µl 20 - 10'000 µl Weighing range 0 - 22 g 0 - 220 g Readability 0.001 mg 0.01 mg Repeatability 0.0015 mg 0.015 mg*) according ISO8655Balance AccessoriesItem Order no.Item Order No.RFID Reader for Calibry Software 30215407Motion Sensor typ "Light Barrier"11140029USB-RS232 Cable 30091827FootSwitch 11106741Ethernet Interface 11132515Weighing Table XPE26PC 11138041RS232 Interface 11132500Weighing Table XPE20511138042Suction pump with tubes 11138268CarePac S Testweight set 1g / 20g 11123006Motion Sensor typ ErgoSens 11132601CarePac S Testweight set 10g / 200g 11123001Pipette Data Management Software functionalities Calibry Single Station Calibry NetworkSoftware package, 1 balance license included 1113841911138420Windows 7 (SP1), 8 and 10 compatible ••Number of max.balances supported 520Databases to manage Pipettes, Methods and Customers ••Calibration Task Planning with reminder ••Calibration report with customization ••ISO8655 compliant and free definable Methods ••Calibration Methods with split, As Found, Maintenance, As Return data••Pipette History data and trending of performance ••Z-factor according to ISO8655, TR or custom with formula editor••Advanced settings for additional uncertainty calculations ••RFID Calibration & Service tracking with MethodCards, SmartTags and Rainin pipettes••System Testing with balance internal & test weights ••Calibry License OptionsInstrument License 1 - to connect 1 additional balance 3041576830415768Instrument License 3 - to connect 3 additional balance 3041732630417326Instrument License 5 - to connect 5 additional balances -30417327Instrument License 1 - to connect 1 other brand balance 3042138230421382User Management License - to manage user rights 30415770included Audit Trail License - to document all system changes 3041577130415771Export File license - - to export in XML and MS Office 30417468included Capture Tool License - to automatically integrate allenviromental data 3041576930415769Evaporation trapsModel Evaporation Trap 10ml Evaporation Trap 20 ml Evaporation Trap 100 ml Order no.111400411114004311138440Compatible with XPE 26 / 56 Micro balance XS / XPE Analytical balance XS /XPE Analytical balance Typical Calibration Range 1 - 200 µl 20 - 1'000 µl 100 - 10'000 ul Volume container 10 ml 6 ml & 20 ml 100 ml Material Aluminium / POM-esd Aluminium / GlassAluminium / POM-esdMETTLER TOLEDO GroupLaboratory DivisionLocal contact: /contactsSubject to technical changes© 10/2017 METTLER-TOLEDO. All rights reserved30393683Global MarCom 2280 LK/PH /pipcalExpect more from usWith decades of experience in pipetting & weighing METTLER TOLEDO can offer you a wide range of online learning resources. Take advantage of our expertise to enhance your know-how and make the most out of your equipment. Check out the services on our internet for a wide range of relevant services and professional solutions we offer.Installation and QualificationTake the stress-free route to meet your producti-vity, quality and regulatory requirements imme-diately. Your specific needs can be addressedby choosing the most suitable option from our comprehensive service offering./serviceSmartStand – Never miss a calibrationAvoid costly efforts and retry's with out-of-specification pipettes or those are beyond cali-bration date. Rainin XLS+ with RFID tags showtheir status every time you put them on the stand.Combined with the EasyDirect Software you can monitor and manage all pipettes in your lab./smartstandRainin pipettes – performance you can trustIts comfortable handle, light springs and “Magne-tic Assist™” technology, ensure light and smoothoperation, while significantly reducing the risk ofrepetitive strain injuries. Tip shaft options includedlow-force LTS™ for improved ergonomics and universal fit./rainin。