Traceability of torque transducers under rotating and dynamic operating conditions

Torque transducers in industrial applications are usually used under dynamic and rotating operating conditions. The present article provides a survey of state-of-the-art studies which describe methods for providing traceability of torque measurements under such operating conditions.The method of investigating the effects of rotation is a comparison of measurements of torque in a rotating shaft train gained simultaneously with two different methods. The first method is using a rotating torque transducer, the second one is with a cradle-mounted absorption dynamometer. The method for investigating the effects of dynamic torque is based on experiments with periodic torque but only minimal rotational motion. Torque is generated by a rotary exciter which forces a setup with a torque transducer and some auxiliary components into a periodic rotary motion. The torque measurement provided by the torque transducer is compared to a reference torque. The reference torque is gained by accurately measuring the angular acceleration of the rotation in conjunction with a priori knowledge of the mass moment of inertia.The developments on the periodic dynamic torque have been performed by the Physikalisch-Technische Bundesanstalt (PTB), the German National Metrology Institute. The investigations on rotating torque transducers have been performed by Hottinger Baldwin Messtechnik (HBM), Germany, a manufacturer of torque transducers with a wide experience in torque calibration.     

A new approach to test torque transducers under dynamic reference regimes

A system is proposed to test torque transducers under reference dynamic regimes, where the reference torque is provided by the application of angular acceleration to a coupled mass moment of inertia. The dynamic regimes include different angular velocity intervals, angular velocity steps and high torque rates. A basic general assembly is proposed and theoretical and practical analyses are performed to determine the primary parameters and depict components. The results show that the angular velocity and torque curves are repeatable and also that the simultaneous responses of torque and acceleration are linear. The mass moments of inertia involved in the measurement process are evaluated. The results provide a positive direction for future tests with transducers and the objective to fill the gap in the metrological traceability chain for torque measurement with dynamic tests and sensor verification.     

Measuring the torque of rotating shafts

Measurement of the torque of elastic beams on the basis of the beat frequency is considered. The beat frequency is determined by means of broad-band frequency modulation of high-frequency sweep generators.     

旋转圆盘空蚀实验设备电机功率的选择

介绍了两种计算旋转圆盘空蚀实验设备电机功率的方法,分别是通过计算流体冲击压力(方法一)和按搅拌器处理(方法二)的功率计算法,给出了计算实例,分析了转盘转速和尺寸对计算结果的影响。结果表明:在结构尺寸一定的情况下,用两种方法计算所得的功率以相近的指数规律随转速的增加而增加;用计算结果进行电机功率设计都是可行的,方法二具有更高的安全裕度;转盘转速和直径都对计算结果有影响,两参数对方法一的影响程度相近,但直径参数比转速对方法二的影响更大。     

一种新型风电传动轴扭矩测试设备开发研究

针对一种新型风电传动轴扭转性能的测试需求,拟定了滑动扭矩、静态扭矩及滑动扭矩耐久三个试验项目检测该轴扭转性能,给出了试验台总体设计方案;主要对液压动力系统进行了适应性分析与设计,详细设计了基于工控机的软硬件控制系统,制定了测试流程,对传感器信号实时采集、展示,并计算、存储及动态再现。开发的试验台已投入运行,取得了较好的检测效果,为新型风电传动轴的研发提供了可靠的性能指标。     

Standard uncertainty evaluation in image-based measurements

The present paper is devoted to address the use and evaluation of measures coming from digital images in an industrial context. Starting from a discussion about the importance and role of this class of measurements, the authors show the architecture of an image-based measurement system and introduce the important issue of the related uncertainty then coming to investigate models and methods for evaluating it.

After presenting an original method for evaluating the uncertainty of images deriving measurements, some examples of practical interest are introduced and evaluated leading the reader to the understanding of related problems. The paper is also enriched by the presence of an introductive section discussing a bibliography of the state of the art in the field.     

传动轴扭矩测量误差分析

传动轴扭矩测量是研究车辆动力系统性能的重要手段.介绍了传动轴扭矩精确测量的重要性,给出了影响传动轴扭矩测量精度的一些因素,并详细分析了由传动轴扭矩应变式测量方式、传动轴本身产生的弯矩以及传动系统带来的扭振对测试结果所产生的影响,为下一步更精确地测量传动轴的扭矩打下了坚实的基础.     

The influence of temperature and humidity on the sensitivity of torque transducers

This paper presents a study of the effect of temperature and relative humidity on the sensitivity and the characteristics of torque transducers such as residual zero torque, reversibility and creep. Temperature and humidity coefficients of the sensitivity take positive as well as negative values. Linear dependence is found between the influence of temperature/relative humidity and the applied load. For some torque transducers, under temperature change the sensitivity has a transient overshoot reaching up to 3 times the steady amplitude. Also there is a small effect of temperature/relative humidity on the transducer’s parameters such as residual zero torque, reversibility and creep. Equations are presented to predict the effect of temperature/relative humidity changes on the sensitivity of torque transducers.     

A/B双摆角数控万能铣头摆角力矩的计算研究

通过理论推导和计算给出了A/B双摆角数控万能铣头摆角力矩的计算公式,并初步验证了公式的正确性.摆角力矩计算公式的研究对摆角铣头的结构设计具有重要的指导意义.     

The uncertainty of torque primary standards: a comprehensive analysis

The development of high-accuracy torque primary standards constitutes the first step towards the harmonisation of the unit of measurement and the realisation of a reliable traceability chain for torque transducers, torque wrenches and screwdrivers. In this paper, a detailed analysis of the uncertainty budget of torque primary standards is proposed. On the basis of the characteristics of the realisations set up by some of the European National Metrological Institutes, as they are available in the literature, the order of magnitude of the uncertainty such systems can achieve is derived. To this extent, attention has been focused on the main questions in the design and in carrying out the measurement of the quantities that determine the main contributions to the uncertainty. Particularly, from the latter point of view, an investigation on the measurement of the friction torque, which is responsible for the degradation of the metrological performances in the lower part of the working range, has been performed.     

Reducing the uncertainty in real-time impedance measurements

This paper arises from the exigency of enhancing the performance of a VXI-based digital meter designed for real-time tracking of impedance. Specifically, the metrological characterization of the meter has put into evidence that the experienced measurement uncertainty is mostly due to wide-band noise corrupting the acquired signals. With the aim of reducing its noise susceptibility without compromising the measurement rate, two digital signal-processing solutions are proposed. The first one pre-processes the acquired signals by means of predictive digital filtering for improving zero-crossing detection and, consequently, granting more reliable phase displacement measurements. The second solution evaluates the inner product of the signals of interest in order to average noise during the course of measurement, thus limiting its effect on the overall uncertainty. Many impedance measurements are carried out to draw a proper comparison between the proposed solutions.     

Traceability and uncertainty analysis in volume measurements

Laboratories must ensure that obtained results are reliable, for that it is necessary to calibrate glassware and proving tanks using the correct method and estimate of uncertainties. The aim of this work is to present the gravimetric method as a suitable and traceable method to calibrate glassware according to laboratory requirements. Moreover, the model for the calculation of the measurement uncertainty is described and it is proved to be completely suitable for the calibration by gravimetric method through a numerical example drawn from the INRIM uncertainty budget in the CCM.FF-K4 key comparison.     

Expression of uncertainty in fuzzy scales based measurements

Fuzzy scales were introduced as a transition between weak scales and strong scales. Preceding studies on fuzzy scales considered only ideal exact measurement without any consideration of uncertainty. The goal of this paper is to present a general approach for the management of uncertainty within the context of fuzzy scale based measurements. After a short reminder on fuzzy scales, a method to define a probability density function or a possibility function on indications given by a fuzzy scale based measurement is exposed. Finally, a method based on the evidence theory is applied to build simultaneously a probability density function and an associated possibility function.     

液力变矩器性能实验台的研究

从提高试验精度，加快试验周期出发，结合性能试验的要求，依靠现代信号采集、传输、处理技术，搭建了一个新型液力变矩器性能实验台。分析了实验台的扩展试验，为液力变矩器的进一步开发提供了可靠的实验平台。     

Measurement uncertainty evaluation of optical multi-sensor-measurements

Optical coordinate metrology facilitates the set-up of in-line applications for quality inspection in shop floor for a variety of products. Yet, for situations with high requirements it is not possible to fulfill all demands by devices based on a single measurement principle. To enable high measurement rates and as well as precise and contact-less data acquisition, a combination of subsystems with different principles and properties has to be implemented. To assure the fitness of an optical multi-sensor-measurement system combining a shadow system and a light-section system for the in-line inspection of concave extruding profiles, an experimental measurement uncertainty analysis has been performed. To this aim, a prototype is set-up and the effect of typical environmental influences like dust, object’s vibrations, the illuminations’ pitch error or extraneous light, is examined. Subsequently, the measurement system is evaluated under shop floor conditions and the results are analyzed.     

Measurement uncertainty of adaptive Chirp-z transform

In this paper analysis of measurement uncertainty of Adaptive Chirp-z transform (ACT) algorithm for power frequency measurement is presented. ACT is a new algorithm developed for real time monitoring of power frequency. Every element (hardware and software) of measurement chain is contributing to the total measurement uncertainty. The analysis of passive voltage dividers, analog-to-digital converters, numeric algorithms and processors (word length and type of arithmetic) are also presented. Estimated values of each contributing part of measurement chain are calculated to the final expression of measurement uncertainty.     

回转件机加工中的同步检测

提出了一种将回转件的机加工与其检测同时进行的方法，并对其重要意义、监测装置、工件原理、数据采集与处理、计算机显示内容及方法进行了详细论述。     

Evaluation of uncertainty in measurements based on digitized data

The paper deals with the uncertainty in measurement based on digital signal processing algorithms, like those achievable with the virtual instruments. The correct estimation of bias and uncertainty is discussed with reference to a simple case study. Three possible approaches to this question are examined and compared. It is shown how a Monte Carlo method, based on numerical simulations and implemented with commercial software packages, can allow virtual instruments to perform an auto-evaluation of both bias and uncertainty affecting their results. Some theoretical considerations, computer simulations and experimental tests are shown to support the proposed technique.     

Research of contactless power transmission in rotating EDM system

Journal of Mechanical Science and Technology - In order to solve the problems of electrode radial run-out, brush wear, and low electrode speed in traditional electric discharge machining (EDM),...