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一种新颖的死区补偿时间测量方法 被引量:57
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作者 孙向东 钟彦儒 +1 位作者 任碧莹 周炳 《中国电机工程学报》 EI CSCD 北大核心 2003年第2期103-107,共5页
该文详细分析了死区效应对逆变器输出性能的影响。同时,针对三相平衡负载,也讨论了基于平均定子电流的定子侧直流等效电路模型,根据在同一个开关周期内,两种不同的有效电压矢量作用时间与相应的定子电流关系,实现了死区补偿时间的离线... 该文详细分析了死区效应对逆变器输出性能的影响。同时,针对三相平衡负载,也讨论了基于平均定子电流的定子侧直流等效电路模型,根据在同一个开关周期内,两种不同的有效电压矢量作用时间与相应的定子电流关系,实现了死区补偿时间的离线动态调整,然后由测量的补偿时间再进行死区效应的在线补偿。另外,根据功率模块相关参数随电流变化导致输出电压损失不同,该文还采用了按照输出电流大小采用不同的死区补偿时间来进行补偿。最后,进行了补偿前和补偿后的实验,结果表明该方法具有较好的补偿效果。 展开更多
关键词 死区补偿 时间测量方法 逆变器 三相平衡负载 功率模块
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基于游标时间测量方法的超声波热量表系统
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作者 郭锐 李虹 +4 位作者 杨宇 牛睿 熊红权 王玉荣 徐殊凝 《太原科技大学学报》 2012年第5期341-345,共5页
为了提高超声波热量表的测量精度及降低功率损耗,设计了一种超声波热量表。在超声波热量表的原理上,选用时间游标测量法、四线制引线方式和C8051F320单片机。实验结果表明,该设计出的超声波热量表功耗低、精度高,可持续工作7年。
关键词 热量表 超声波 游标时间测量方法
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减速器的运转和动态参数的时间测量方法
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作者 王信化 M.,AH 《国外金属加工》 2002年第2期60-63,共4页
  减速器使用中除了保证传动力距之外,保证其传动比是减速器工作能力的指标之一.减速器工作中伴生传动比偏差,其大小一般为百分之几,以啮合传动的运动和动态过程为条件.现在评估减速器传动比的偏差是以相位方法,应用CN-66,KH-7Y和ИК...   减速器使用中除了保证传动力距之外,保证其传动比是减速器工作能力的指标之一.减速器工作中伴生传动比偏差,其大小一般为百分之几,以啮合传动的运动和动态过程为条件.现在评估减速器传动比的偏差是以相位方法,应用CN-66,KH-7Y和ИКТ-2M式的运动测量表来实现.…… 展开更多
关键词 减速器 动态参数 时间测量方法 运动参数 传动式
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一种油品黏度测定过程中时间间隔测量方法研究
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作者 董小丽 曹鹏章 +1 位作者 李安 王天明 《石油工业技术监督》 2020年第4期21-24,共4页
针对目前石油化工产品的运动黏度测量过程中人工计量时间测定误差大、效率低、测定数据无法溯源的问题,根据采用毛细管进行运动黏度测定的方案,研究设计了一种精确的黏度测定过程中时间间隔测量方法。该方法主要通过计算机软件控制摄像... 针对目前石油化工产品的运动黏度测量过程中人工计量时间测定误差大、效率低、测定数据无法溯源的问题,根据采用毛细管进行运动黏度测定的方案,研究设计了一种精确的黏度测定过程中时间间隔测量方法。该方法主要通过计算机软件控制摄像头监视和采集整个运动黏度检测的流程,在检测流程开始前先测定上、下2个刻度的位置,然后在监视过程中自动判断液面位置,当液面与2个刻度位置重合时记录时间信息,利用2个时间的间隔测定油品的运动黏度,同时将整个测定流程视频数据上传至数字化信息中心。由实际的油品运动黏度测定实验发现,所设计的时间间隔测量方法具有操作简单、时间计量准确、测定效率高的特点。 展开更多
关键词 运动黏度 时间间隔测量方法 毛细管 视频处理
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显示器的响应时间和拖尾时间 被引量:4
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作者 徐康兴 《现代显示》 2005年第5期22-26,共5页
本文肯定了响应时间在静止图形切换场合下的应用价值,同时指出它在活动图像显示中的适用性遭到质疑。根据显示亮度与激励信号的时间关系,提出了亮拖尾时间和暗拖尾时间的确切定义。进而讨论了影响拖尾时间的种种因素以及拖尾时间与响应... 本文肯定了响应时间在静止图形切换场合下的应用价值,同时指出它在活动图像显示中的适用性遭到质疑。根据显示亮度与激励信号的时间关系,提出了亮拖尾时间和暗拖尾时间的确切定义。进而讨论了影响拖尾时间的种种因素以及拖尾时间与响应时间之间的区别和联系。最后,介绍一种简单易行的拖尾时间测量方法。 展开更多
关键词 响应时间 拖尾 显示器 时间测量方法 应用价值 图像显示 时间关系 激励信号 显示亮度 适用性 切换
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含参考光路的时间差法动态调焦式光学测头
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作者 樊玉铭 张国雄 +5 位作者 高翔 裘祖荣 郭敬滨 张宏伟 李智 赵树忠 《天津大学学报(自然科学与工程技术版)》 EI CAS CSCD 北大核心 2005年第5期405-410,共6页
为了满足对机械件、光学件和电子件等几何形貌质量控制和产品监测越来越高的要求,在动态主动调焦法测量原理的基础上,提出一种含参考光路的时间差法动态调焦式光学测头的检测方法.论述了该测头通过测量参考光路和测量光路的时间差实现... 为了满足对机械件、光学件和电子件等几何形貌质量控制和产品监测越来越高的要求,在动态主动调焦法测量原理的基础上,提出一种含参考光路的时间差法动态调焦式光学测头的检测方法.论述了该测头通过测量参考光路和测量光路的时间差实现位移测量的测量原理及其结构,并对这种新的测量方法进行了详细的误差分析,对该光学测头及其测量系统进行了各项实验.实验表明,含参考光路的时间差法动态调焦式光学测头及其测量系统的测量范围为±0.1mm,测量分辨力为0.075μm,线性度误差约为0.45μm. 展开更多
关键词 光学测头 动态主动调焦法 调焦式时间测量方法
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基于MTM-TDABC的A公司电脑包装纸箱制造成本核算 被引量:1
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作者 郭春东 谢启博 《现代工业经济和信息化》 2023年第8期324-328,共5页
针对传统基于时间驱动成本核算(TDABC)实际应用中各生产活动有效工时难以获得而导致成本核算不准确的问题,提出将时间测量方法(MTM)与TDABC相结合的成本核算方法,以标准工时计算方法将实际生产活动分解为对应的动作元素,从而获得整个生... 针对传统基于时间驱动成本核算(TDABC)实际应用中各生产活动有效工时难以获得而导致成本核算不准确的问题,提出将时间测量方法(MTM)与TDABC相结合的成本核算方法,以标准工时计算方法将实际生产活动分解为对应的动作元素,从而获得整个生产活动的总生产时间,并以此时间为基础核算生产活动的成本消耗。在理论介绍的基础上,结合A公司电脑包装纸箱产线进行了MTM-TDABC应用分析,核算出一个成本周期内各产品的实际成本情况,并根据成本核算结果从产线整体及单个产品两个层面分析成本结构,给出成本优化的思路和方法。 展开更多
关键词 时间驱动作业成本法 时间测量方法 成本管理 电脑包装箱生产
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蔡茂林教授代表中国赴德国法兰克福参加ISO/TC131年会
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《液压与气动》 北大核心 2015年第12期38-38,共1页
2015年10月19-24日,北京航空航天大学蔡茂林教授,应全国液压气动标准化技术委员会的委托,以SAC/TC3国际专家的身份代表中国赴德国法兰克福参加ISO/TC131年会。其中,ISO/TC131/SC5/WG3会议针对ISO6358《气压传动使用可压缩流体... 2015年10月19-24日,北京航空航天大学蔡茂林教授,应全国液压气动标准化技术委员会的委托,以SAC/TC3国际专家的身份代表中国赴德国法兰克福参加ISO/TC131年会。其中,ISO/TC131/SC5/WG3会议针对ISO6358《气压传动使用可压缩流体的元件的流量特性测定》部分条款的修订和iSO12238(气压传动方向控制阀切换时间的测量》关于电磁阀开关时间测量方法的确定进行了讨论,关于控制阀能量损失的计算,工作组组长Berninger先生提出了基于Enthalpy的方法,与蔡茂林教授提出的基于AvailableEnergy的方法存在较大差异,经过充分沟通,Berninger先生基本理解并认可后者的合理性。 展开更多
关键词 德国法兰克福 ISO 年会 中国 北京航空航天大学 标准化技术委员会 时间测量方法 方向控制阀
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A new process monitoring method based on noisy time structure independent component analysis 被引量:2
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作者 蔡连芳 田学民 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第1期162-172,共11页
Conventional process monitoring method based on fast independent component analysis(Fast ICA) cannot take the ubiquitous measurement noises into account and may exhibit degraded monitoring performance under the advers... Conventional process monitoring method based on fast independent component analysis(Fast ICA) cannot take the ubiquitous measurement noises into account and may exhibit degraded monitoring performance under the adverse effects of the measurement noises. In this paper, a new process monitoring approach based on noisy time structure ICA(Noisy TSICA) is proposed to solve such problem. A Noisy TSICA algorithm which can consider the measurement noises explicitly is firstly developed to estimate the mixing matrix and extract the independent components(ICs). Subsequently, a monitoring statistic is built to detect process faults on the basis of the recursive kurtosis estimations of the dominant ICs. Lastly, a contribution plot for the monitoring statistic is constructed to identify the fault variables based on the sensitivity analysis. Simulation studies on the continuous stirred tank reactor system demonstrate that the proposed Noisy TSICA-based monitoring method outperforms the conventional Fast ICA-based monitoring method. 展开更多
关键词 Process monitoring Independent component analysis Measurement noises KURTOSIS Mixing matrix Contribution plot Sensitivity analysis
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Direct fitting measurement of gas content in coalbed and selection of reasonable sampling time 被引量:1
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作者 Yan Guoqiang Wang Gang +2 位作者 Xin Lin Du Wenzhou Huang Qiming 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2017年第2期299-305,共7页
In this study, we selected 9 typical coal samples with different metamorphic grades as the study subjects,measured their initial 30-min gas desorption at 30℃ and different pressure using a self-developed gas adsorpti... In this study, we selected 9 typical coal samples with different metamorphic grades as the study subjects,measured their initial 30-min gas desorption at 30℃ and different pressure using a self-developed gas adsorption/desorption device. Based on the characteristics of gas desorption from coal samples, we proposed a direct fitting method for measurement of gas content in coalbed, analyzed the effects of sampling time on the measurement results and determined the reasonable sampling time of coal samples with different metamorphic grades at different gas adsorption pressure at equilibrium. The results show that (1)the error of gas contents obtained using the direct fitting method relative to that obtained using indirect method is less than 10%, which meets the actual on-site requirements and verifies the feasibility of the direct fitting method;(2) when the relative error is controlled within ±10%, the reasonable sampling time of coal samples is linearly related to the gas adsorption pressure at equilibrium;(3) the reasonable sampling time of coal samples with the same metamorphic grade exhibits a shortening trend with increasing gas adsorption pressure at equilibrium;(4) for coal samples with similar gas adsorption pressure at equilibrium, the reasonable sampling time of coal samples displays a shortening trend with increasing metamorphic grade. Overall, the study provides a basis for improving the measurement accuracy of gas content in coalbed. 展开更多
关键词 Gas content Fitting Desorption Metamorphic grade Sampling time
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Damage detection of frames using the increment of lateral displacement change
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作者 王建民 陈龙珠 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第3期202-212,共11页
The method proposed in this paper is based on the fact that the damage in different types of structural members has distinctive influence on the structural stiffness. The intrinsic mechanical property of the structure... The method proposed in this paper is based on the fact that the damage in different types of structural members has distinctive influence on the structural stiffness. The intrinsic mechanical property of the structure is tapped and fully utilized for damage detection. The simplified model of the flexibility of frames treats the individual storeys as springs in series and the frame as an equivalent column. It fully considers the main deformation of all beams and columns in the frame. The deformation property of the simplified model accorded well with that of the actual frame model. The obtained increment of lateral displacement change (IOLDC) at the storey level was found to be very sensitive to the local damage in the frame. A damage detection method is pro- posed using the IOLDCs as the damage identification parameters. Numerical examples demonstrate the potential applicability of this method. 展开更多
关键词 Damage detection Increment of lateral displacement change Static test FRAME Equivalent column
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Estimation of the Gauging and the Calibration Time Interval for the Modern Total Stations
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作者 Evangelia Lambrou Antonios Antonakakis 《Journal of Civil Engineering and Architecture》 2015年第10期1210-1216,共7页
The modern TSs (total stations) have reached a very high level in the provided reading and reliability (accuracy and precision) of their measurements. The evolution of the digital technology has helped in this dir... The modern TSs (total stations) have reached a very high level in the provided reading and reliability (accuracy and precision) of their measurements. The evolution of the digital technology has helped in this direction. Thus, the TSs can support all requirements for the stake out and monitoring of modern survey engineering and constructions projects. Their complicated manufacturing process and the sensitivity of their components require gauging, adjusting and calibration at certain time intervals. This appears to be the only way in order to assure the precision of measurements provided by the manufacturer and the reliability of the works they are used for. The goal of this paper is to propose a method for the estimation of the gauging time interval for modern YSs. which could be used by any user. More specifically, the indispensable need for the TSs gauging is elevated and documented. All the parameters that influence their operation are registered. A model expressed by a scale of grades is defined, leading thus to an equation for the calculation of the time interval for the next needed gauging and calibration. 展开更多
关键词 Total station metrological check gauging CALIBRATION time interval.
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Investigations of 3D Surface Roughness Characteristic's Accuracy
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作者 Maris Kumermanis Janis Rudzitis Anita Avisane 《Journal of Mechanics Engineering and Automation》 2013年第10期632-640,共9页
The existing surface roughness standards comprise only two dimensions. However, the real roughness of the surface is 3D (three-dimensional). Roughness parameters of the 3D surface are also important in analyzing the... The existing surface roughness standards comprise only two dimensions. However, the real roughness of the surface is 3D (three-dimensional). Roughness parameters of the 3D surface are also important in analyzing the mechanics of contact surfaces. Problems of mechanics of contact surfaces are related to accuracy of 3D surface roughness characteristic. One of the most important factors for 3D characteristics determination is the number of data points per x and y axes. With number of data points we understand its number in cut-off length. Number of data points have substantial influence on the accuracy of measurement results, measuring time and size of output data file (especially along the y-axis direction, where number of data points are number of parallel profiles). Number of data points must be optimal. Small number of data points lead to incorrect results and increase distribution amplitude, but too large number of data points do not enlarge range of fundamental information, but substantially increase measuring time. Therefore, we must find optimal number of data points per each surface processing method. 展开更多
关键词 Surface topography roughness assessment accuracy measurement instruction.
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High-precision time and frequency measurement method combining time-space conversion and different frequency phase detection 被引量:4
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作者 DU BaoQiang WANG YanFeng +3 位作者 CUI GuangZhao GUO ShuTing DONG ShaoFeng LIU Dan 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第11期2110-2115,共6页
According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and st... According to the time&space conversion relations and different frequency phase detection principle,an ultra-high precision time&frequency measurement method is proposed in this paper.The higher accuracy and stability of the speed of light and electromagnetic signals during the transmission in space or a specific medium enable the measurement of short time interval which uses the coincidence detection of signal’s transmission delay in length.The measurement precision better than 10 picoseconds can be easily obtained.The method develops the length vernier utilizing the stability of signal’s transmission delay,minimizes the fuzzy region of phase coincidence between the standard frequency signal and the measured signal,approaches the best phase coincidences and therefore improves the measurement precision which is higher than the precision provided by the traditional methods based on frequency processing.Besides,the method costs less than the traditional methods and can also solve the problem of the measurement of super-high frequency.Experimental results show the method can improve the measurement precision to 10 12/s in the time&frequency domain. 展开更多
关键词 time and space conversion delay-time phase shift different phase coincidence detection group phase difference
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