Bilateral comparisons of measurement capabilities for the calibration of low nominal capacity torque measuring devices between NMIJ and PTB in the range from 0.1 N m to 10 N m using different procedures

Bilateral comparisons of the calibration of low nominal capacity torque measuring devices (TMDs) were conducted between NMIJ and PTB for the first time. A 10 N m deadweight torque standard machine (TSM) newly developed at NMIJ was compared with PTB’s two TSMs with nominal capacities of 1 N m and 1 kN m, in the range from 0.1 N m to 10 N m. The transfer measurement devices used had nominal capacities of 1 N m and 10 N m. The comparisons were made using two calibration procedures: one based on the CCM.T-K2 Key Comparison procedure and the other according to the daily calibration procedure adopted at each institute. As a result, the torque realized by the TSM at NMIJ was shown to be equivalent to that realized by the two TSMs at PTB. In addition, it was confirmed that the daily calibration procedures of both institutes yielded consistent results in the calibration of low nominal capacity TMDs.     

Range expansion of the reference torque wrench calibration service to 5 kN m at NMIJ

The reference torque wrench (RTW) calibration service within the range from 5 N m to 1 kN m has been provided to industry by the National Metrology Institute of Japan (NMIJ) in the National Institute of Advanced Industrial Science and Technology (AIST). Reflecting the strong demand from Japanese industry, the calibration range was extended to 5 kN m. First, a high-precision torque transducer in the form of a torque wrench with a rated capacity of 5 kN m was developed in order to establish a calibration method for such a large RTW. Second, the calibration method was investigated using a deadweight type torque standard machine with a rated capacity of 20 kN m as a reference standard. Aimed expanded calibration range is from 200 N m to 5 kN m. As a result of calibration experiment using three transducers having different rated capacities, a relative expanded uncertainty of less than 7.0 × 10⁻⁵ could be obtained at a certain calibration point in the best case.     

Determination of the averaging time for precision calibration of a build-up system in a deadweight force machine

This paper describes the determination of the optimal averaging time for the precision calibration of a build-up system. When a build-up system is calibrated using a deadweight machine, the oscillating signal components of force transducers in the build-up system are strongly related to the motion of the deadweight. We propose a model based on the analysis of oscillating signals of force transducers to measure the deadweight oscillation. In this paper, we have investigated the behavior of deadweight motion for a deadweight force machine of 498 kN using the proposed model, and also determined the optimal averaging time for the output signals of force transducers in a build-up system. It revealed that the deadweight force machine has a periodic oscillation of frequencies of about 0.23 and 0.8-1.5 Hz in which the 0.23 Hz component comes from the pendulum motion of the deadweights and the 0.8-1.5 Hz comes from the bounce-mode oscillations of weights. If the length of the rectangular window can be set equal to the period of the deadweight oscillation in a build-up system, the error due to the deadweight oscillation diminishes, regardless of the initial phase of signal fluctuation and the initial time of measurement.     

基于气浮轴承技术的小扭矩标准机的研制

介绍上海市质量监督检验技术研究院研制的扭矩标准机的研究过程。对该标准机的工作原理、机械结构和关键技术等进行了论述,并对该标准机进行了不确定度分析,表明该机的不确定度小于5×10-4(k=2)。     

汽车轮毂螺母拧紧扭矩分析及质量控制

详细介绍了螺纹连接原理及螺栓拧紧技术,动态、静态扭矩的概念,影响因素及应用场合,阐述了汽车装配过程中不同连接件性质的扭矩衰减后动态扭矩与静态扭矩的关系.通过采集轮毂螺母拧紧扭矩数据进行SPC统计分析,同时结合经验公式验证了计算静态扭矩的控制范围的可行性和正确性,总结出一种动、静态扭矩的相互转化方法,该方法大大提高了生产...     

PMSM直接转矩控制调速系统中转矩增量分析

直接转矩控制技术已经成功应用于异步电动机的控制中,而且越来越多的学者将其应用推广到其他种类的电机,特别是永磁同步电动机。但是目前较少有文献针对永磁同步电动机在直接转矩控制调速系统中电机的转矩增量进行分析,文章着重对此进行了理论分析,从中可以深入分析电机转矩的控制原理,并且从中可以寻求加快转矩响应的方法,对提高系统转矩控制性能有参考意义。     

Improved system for the automatic calibration of standard resistors in the meg-ohm range

An automated measuring system has been developed to improve the calibration of high value standard resistors in the meg-ohm range at the National Institute for Standards (NIS), Egypt. This system is suitable for the calibration of the standard resistors from 100 kΩ to 100 MΩ using the DMM-based method by the substitution technique where the unknown resistor and the standard resistor are indirectly compared in the same position using a dummy resistor as a short-term reference standard. The system operation is automatically controlled by using a Lab VIEW program which is especially developed for this purpose. The uncertainty for the high value standard resistors measurement of this system is estimated. The performance of this system is also evaluated by comparing the measurement results obtained from this technique with those obtained by the direct comparison DMM-based method. It is found that the measurement uncertainty of with this method spans from 4.1 × 10⁻⁶ to 27 × 10⁻⁶, while it spans from 40 × 10⁻⁶ to 110 × 10⁻⁶ for the direct comparison method. The relative differences of the deviation from nominal values of the working standards resistors measured by the two methods are found to be within their expanded uncertainties.     

Theory-based metrological traceability in education: A reading measurement network

Huge resources are invested in metrology and standards in the natural sciences, engineering, and across a wide range of commercial technologies. Significant positive returns of human, social, environmental, and economic value on these investments have been sustained for decades. Proven methods for calibrating test and survey instruments in linear units are readily available, as are data- and theory-based methods for equating those instruments to a shared unit. Using these methods, metrological traceability is obtained in a variety of commercially available elementary and secondary English and Spanish language reading education programs in the U.S., Canada, Mexico, and Australia. Given established historical patterns, widespread routine reproduction of predicted text-based and instructional effects expressed in a common language and shared frame of reference may lead to significant developments in theory and practice. Opportunities for systematic implementations of teacher-driven lean thinking and continuous quality improvement methods may be of particular interest and value.     

Evaluation of moment arm length and fulcrum sensitivity limit in a 10 N·m dead weight torque standard machine

Many torque tools, such as torque wrenches and torque screwdrivers, as well as torque measuring devices (TMDs) with a rated capacity of less than 5 N·m are being widely used in industry. Thus, a small-rated-capacity torque standard has to be established as soon as possible. A 10 N·m dead weight torque standard machine (10 N·m DWTSM) has been under development since 2006 at the National Metrology Institute of Japan (NMIJ), part of the National Institute of Advanced Industrial Science and Technology (AIST). Characteristically, the main parts of the moment arm are made of low thermal-expansion alloy (Super INVAR), and an aerostatic bearing is employed as the fulcrum supporting the moment arm to minimize rotational friction. The moment arm was evaluated with regard to the coefficient of thermal expansion (CTE), the lengths measured by a 3D coordinate measurement machine (CMM), and temperature correction realized by measuring the moment arm temperature. The sensitivity limit of the fulcrum in the 10 N·m DWTSM was also estimated. As a result, the apparent overall CTE of the moment arm was 1.06 × 10⁻⁶ K⁻¹, and the expanded uncertainty was 2.24 × 10⁻⁹ K⁻¹ (k = 2). The results of the CMM measurement were a right-hand side length of 510.2773 mm and a left-hand side length of 510.2657 mm, with a relative expanded uncertainty of 4.0 × 10⁻⁵ (k = 2). The moment arm temperature increased by approximately 0.6 K during the ordinary calibration process. The corresponding change in the lengths of the moment arm was estimated to be approximately 0.3 μm, which is considered to be sufficiently small compared with the expanded uncertainty of the lengths of the moment arm. The fulcrum of the 10 N·m DWTSM was found to have sufficient sensitivity under three conditions: without the weight loading components, with the weight loading components, and with loaded weights. In particular, the fulcrum had sufficient sensitivity of at least 0.5 mg when weights of 100 g were loaded on both 5th stages in the weight loading components to generate a radial load equivalent to 1 N·m.     

相同转矩电流下的交流电机电磁转矩比较研究

对三相异步电机在不同磁场定向下及六相异步电机在梯形波相电流驱动下的电磁转矩进行了比较分析.比较了两种异步电机在突加相同转矩电流情况下的电磁转矩响应曲线.仿真和实验结果验证了六相异步电机比三相异步电机电磁转矩脉动频率高,幅值小,稳定性强以及相同转矩电流下产生电磁转矩高的特点.     

力矩控制在雷达装配中的应用

通过适当的拧紧力矩来控制螺纹装配预紧力是一项重要的装配技术,也是机械装配中的难点.我国在力矩控制方面虽然开展了一些研究,但现有的大部分拧紧力矩标准主要从螺栓强度等级角度列出了力矩数值表,并没有从应用对象、被连接件角度考虑力矩的控制量.文中梳理了雷达装配过程中力矩控制应用的需求对象,讨论了力矩控制工程应用理论基础和力矩确定原则.     

基于DSP对永磁同步电机直接转矩控制技术的研究

首先讨论了永磁同步电机的结构、3个坐标系下的数学模型及其变换方法,实现交流电机多变量及其相互作用的解耦,将交流电机化简并等效成直流电机来进行分析.然后基于TMS320F2812,对永磁同步电机直接转矩控制系统的软硬件平台进行了设计,最后对控制效果进行了实验验证.     

Some issues of traceability in the field of surface topography measurement

This paper highlights some of the reasons that surface topography measurements can have an ill-defined traceability route. Whereas the most common instruments on the shop floor are two-dimensional (2D) or profiling systems, there is a clear industrial trend towards three-dimensional (3D) surface topography instruments. Currently, there is no clear traceability route for three-dimensional measurements, and recent comparisons show alarming discrepancies between the various commercial instruments. This paper reviews these instrumental problems and highlights the need for unambiguous mathematical definitions for surface texture parameters and rigorous uncertainty evaluations. This paper also reviews some of the metrology issues that will be encountered when using three-dimensional surface texture measuring instruments to measure complex features on microsystems.     

复合地层中掘进的盾构机刀盘动态驱动转矩研究

复合地层掘进扭矩载荷突变是造成盾构机掘进过程中堵转停机的直接原因,考虑盾构机刀盘驱动变频调速电机特性、转矩传递过程中齿轮啮合刚度及齿侧间隙等非线性因素,建立冗余驱动的盾构机刀盘切削系统机电耦合动力学模型;针对典型复合地层地质条件,对盾构机在上软下硬地层掘进过程中刀盘驱动转矩动态特性进行仿真分析。结果表明,在软土体积百分比为70%复合地层中,掘进扭矩载荷显著高于50%软土百分比复合地层;盾构机在由50%软土百分比地层掘进进入70%软土百分比地层过程中,刀盘驱动电机负荷瞬间增大,甚至超出其工作极限,电机无法稳定工作,容易导致堵转发生,该结果可以部分解释我国昆明上公山隧道施工中频繁出现堵转事故的原因,为盾构机复杂地质条件下顺应性设计提供指导。     

定扭矩工具在工程机械产品中的选型及应用

对装载机装配生产过程中,需要使用的定扭矩工具进行了分析,总结了根据工程机械的产品的特性及工位需求,选择相适应的定扭矩工具,通过对使用、维护、成本、员工操作便利性等方面进行考虑,选择最合适的定扭矩工具。     

轴承负荷对扭矩激励的敏感度矩阵

针对扭矩激励作用下多轮盘转子系统轴承负荷的复杂变化,采用改进的传递矩阵法,推导了支承负荷的敏感度矩阵。在单位扭矩作用下,推导并分析轴承负荷的变化量。结果表明,与扭矩激励位置相距较近的轴承,负荷受到的影响较大。在任意给定扭矩变化量时,可以准确、方便地计算出相应的轴承负荷变化值,这为扭矩在各跨间的传递耦合特性的理论研究提供了有效的途径。     

无级变速器湿式离合器动态摩擦系数对转矩传递影响的研究

因研究湿式离合器接合特性的需要,通过分析无级变速器湿式离合器的机械结构,建立了湿式离合器机械传动的数学模型,运用建立的数学模型,研究了不同动态摩擦系数斜率对传递转矩的影响。研究结果表明,对于具有正斜率特性的摩擦系数,其传递的转矩是收敛的,而对于具有负斜率特性的摩擦系数,其传递的转矩是发散的。研究结果为进一步研究湿式离合器的传动特性提供了理论基础。     

EPS永磁无刷直流电动机齿槽转矩抑制方法

文章建立了快速分析永磁无刷直流电动机齿槽转矩的数学模型,分析了多种抑制齿槽转矩的方法,并提出了一种有效降低永磁无刷直流电动机齿槽转矩的全新转子结构,给出了齿槽转矩的计算波形,比较了直槽直极和分瓣斜极两种转子结构下齿槽转矩的大小,验证了这种方法的有效性。     

扭矩传感器在步进电机控制系统中的应用

文中介绍了扭矩传感器的结构及其工作原理,详述了扭矩传感器在塑壳式低压断路器智能测控系统中的应用,提出由扭矩传感器、一体化螺丝刀(同心双柔轴机构)、PLC组成的控制系统,实现对一体化螺丝刀的闭环控制,提高了一体化螺丝刀锁紧螺母的控制精度,降低了控制系统的成本,在现场取得了良好的控制效果。     

新型自适应速度观测器在异步电机直接转矩控制系统中的应用

实现高性能直接转矩控制系统的重要环节是准确地观测异步电机的定子磁链，本文将一种新型的速度自适应磁链闭环观测器，应用于直接转矩控制系统中，取代了传统的积分器，理论证明该系统是超稳定系统，仿真与实验表明，该方案对电机磁链的观测精度高，对电机参数的鲁棒性好，同时基于磁链观测器所设计的速度自适应辨识方案准确性好，收敛速度快，使系统在较低转速下仍能保持优良的性能，本系统针对1．1kW异步电机，采用数字信号处理器DSP（TMS320C32）进行了数字化实现，实时控制软件是采用C和汇编语言混合编程实现的。