Nine european national metrology institutes (NMIs) are collaborating in a new project funded by the european metrology research programme (EMRP) to establish traceable dynamic measurement of the mechanical quantities force, pressure, and torque. The aim of this joint research project (JRP) is to develop appropriate calibration methods, mathematical models, and uncertainty evaluation. The duration of the project is 3 years for a global amount of €3.6 million. It began in September 2011.

Computed tomography has entered the industrial world in 1980’s as a technique for non-destructive testing and has nowadays become a revolutionary tool for dimensional metrology, suitable for actual/nominal comparison and verification of geometrical and dimensional tolerances. This paper evaluates measurement results using different measuring strategies applied in different inspection software packages for volume and surface data analysis. The strategy influence is determined by calculating the measurement uncertainty. This investigation includes measurements of two industrial items, an aluminium pipe connector and a plastic toggle, a hearing aid component. These are measured using a commercial CT scanner. Traceability is transferred using tactile and optical coordinate measuring machines, which are used to produce reference measurements. Results show that measurements of diameter for both parts resulted in smaller systematic errors compared to distance and height measurements. It was found that uncertainties of all measurands evaluated on surface data were generally greater compared to measurements performed on volume data.

There have been substantial improvements in measurement systems in order to meet fluctuating market demands. This rapid change and development in measurement technology has primarily been governed by demands of accuracy and precision from aerospace, automotive and other manufacturing industries. Coordinate measuring machines (CMMs) available with different technologies and configurations has efficiently been fulfilling customer demands for more than a decade. Though, current CMMs can meet needs of rapid and increased demands of customers to a greater extent but still there is lot of scope for improvement and development in CMMs. The globalization of manufacturing has resulted in development of variety of complex products and miniaturization of mechanical components. The technology of micro/nano-scale 3D measurement is still a bottleneck for industries. Therefore, precise and accurate system which is flexible enough to deal with complexities of parts and micro & nano range products has to be investigated. In this paper, comprehensive review concerning CMMs with capabilities to measure micro/nano features has been presented. This work has also discussed different methods to estimate measurement uncertainty, as well as performance evaluation of CMMs. Moreover, novel concepts such as intelligent CMM, multi-sensor CMM, virtual CMM have been presented.

Optical and tactile single scanning probes usually are used in dimensional metrology applications, especially for roughness, form, thickness and surface profile measurements. To perform assessments with nanometre level of accuracy, specific ultra-high precision machines have been developed by the National Metrology Institutes (NMIs) such as the LNE, VSL, METAS, SMD, generally in collaboration with industrials and academics partners. Such developments are not devoted only to NMIs but many industrials develop and commercialize their own ultra-high precision machines as the IBSPE and TNO companies. All these machines provide optical and tactile precise measurements and cover a large domain of application such as the form’s characterization of optical lenses. In this paper the performance and capability of ultra-high precision machines of some National Metrology Institutes (LNE, VSL, SMD and METAS) and industrials companies (TNO and IBSPE), involving together in the IND10 European EMRP project titled “Optical and tactile metrology for absolute form characterization”, will be detailed. Theirs probing systems and accuracies levels will be evoked. Relevant results especially for measuring optical lenses will be also presented and discussed.

This article proposes a combined theoretical and experimental approach to assess and quantify the global uncertainty of a high-speed camera velocity measurement. The study is divided in five sections: firstly, different sources of measurement uncertainties performed by a high-speed camera are identified and quantified. They consist of geometrical uncertainties, pixel discretisation uncertainties or optical uncertainties. Secondly, a global uncertainty factor, taking into account the previously identified sources of uncertainties, is computed. Thirdly, a sensibility study of the camera set-up parameters is performed, allowing the experimenter to optimize these parameters in order to minimize the final uncertainties. Fourthly, the theoretical computed uncertainty is compared with experimental measurements. Good concordance has been found. Finally, the velocity measurement uncertainty study is extended to continuous displacement measurements as a function of time. The purpose of this article is to propose all the mathematical tools necessary to quantify the individual and global uncertainties, to highlight the important aspects of the experimental set-up, and to give recommendations on how to improve a specific set-up in order to minimize the global uncertainty. Taking all these into account, it has been shown that highly dynamic phenomena such as a ballistic phenomenon can be measured using a high-speed camera with a global uncertainty of less than 2%.

The paper gives a brief description of the principles and the uncertainty of the acoustic calibration methods that today are applied by National Metrology Institutes and calibration service centers. Even if some of the calibration principles have been applied over more than half a century, the methods and the instrumentation are still being refined in order to minimize their uncertainty, to extend their frequency ranges, to include extra parameters and to speed up slow processes. In addition to the traditional methods for microphone sensitivity and frequency response calibration, new development areas, like for example wind power, has created needs for low-frequency and infra-sound calibration, down to 0.1 Hz. Other high-tech areas have lead to the development of methods for phase response comparison calibration of microphones for large arrays, for sound intensity measurement and for verification of dynamic linearity of microphones at very high sound pressure levels, up to about 174 dB that corresponds to 10 kPa.

In the building domain, components or equipment are often subjected to severe environmental conditions. In order to predict the reliability and the life-time of such equipment, accelerated life testing can be carried out. Severe conditions are applied to accelerate the ageing of the components and the reliability at nominal conditions is then deduced considering that these nominal conditions are not constant but stochastic. In this paper, the accelerated life testing of photovoltaic modules is carried out at severe module temperature levels. The module power losses are monitored and the limit state is determined when a threshold power is reached. The stochastic data and the reliability are simulated during a period of twenty years. Finally, the life time of the component is evaluated.

Evaluation of geometric deviations for the purpose of determining compliance with specified form tolerances requires the acquisition of numerous measured data points and extensive computation to accurately characterize the inspected part’s geometry. If there are not enough data points measured or when the measured points are not distributed properly on the measured surface a high level of uncertainty in characterizing the inspected part’s geometry can be expected. However, increasing the number of data point also significantly increases the computational time and also increases computational uncertainty by adding to instability of the optimization process required to find the minimum deviation zone. Selections of number and location of the measured date points need to be performed by understanding the significance of these two sources of uncertainties. This paper discussed the effect of sampling procedure on uncertainty and precision of flatness inspection.

Measuring the energy efficiency of buildings and its confrontation with the current Building Energy Simulations now faces knowledge of what is commonly called “occupancy”. This work has been made in order to implement a monitoring system on a research demonstrator building at DLRCA in Angers (France). The goals were first to know the occupancy as input data of models but also to build occupancy models. Occupancy can be defined as all the action of occupants that affect building energy efficiency. The chosen monitoring deals with its presence, lightning, windows opening and internal gains. It seems that the use of an Infra- red detector allows a accuracy of 5 min in the detection of presence. The use of dry contact sensors allows the detection of five different rates of slide windows opening that can affect temperature decrease. Light sensors seem to be efficient to detect artificial lighting states when correctly configured.

The Guide to the expression of measurement uncertainty, (GUM, JCGM 100) and its Supplement 1: propagation of distributions by a Monte Carlo method, (GUMS1, JCGM 101) are two of the most widely used documents concerning measurement uncertainty evaluation in metrology. Both documents describe three phases (a) the construction of a measurement model, (b) the assignment of probability distributions to quantities, and (c) a computational phase that specifies the distribution for the quantity of interest, the measurand. The two approaches described in these two documents agree in the first two phases but employ different computational approaches, with the GUM using linearisations to simplify the calculations. Recent years have seen an increasing interest in using Bayesian approaches to evaluating measurement uncertainty. The Bayesian approach in general differs in the assignment of the probability distributions and its computational phase usually requires Markov chain Monte Carlo (MCMC) approaches. In this paper, we summarise the three approaches to evaluating measurement uncertainty and show how we can regard the GUM and GUMS1 as providing approximate solutions to the Bayesian approach. These approximations can be used to design effective MCMC algorithms.

MEMS gyroscopes as a kind of angular rate sensor have been widely used, but their accuracy tends to be low in practical applications, especially under temperature influence, and they generally require error compensation. Based on the analysis of gyroscope operating principle, this paper has shown that the resonant frequency and measuring precision of the gyroscope are dependent on temperature and temperature gradients. The paper has thus proposed a compensation model based on temperature and temperature gradients. The experimental results have demonstrated that the thermal drift of zero bias can be effectively suppressed, and the accuracy can be improved by one order of magnitude after compensation. Compared with compensation methods only based on temperature, the new method gives significantly better performance. The new error compensation model has not only integrated the differences under different temperature conditions, but also reduced the repeatability errors. It provides a theoretical basis for accurate compensation of the gyroscope thermal error in practical applications and is applicable to other MEMS gyroscopes.

Medical measurements are present in the everyday life of people and are fundamental processes in prevention, diagnosis and treatment of disease. Therefore, a growing interest lies in the role of metrological decisions and conformity assessment, namely where measurements are in support of health. This paper focuses on the use of medical devices looking to enhance its metrological traceability, highlighting the specific role of metrology in the field of health care and the impact of legal control in the framework of the medical devices regulation with a measuring function. It is proposed a new regulatory approach for medical devices in use, facing the convergence between European policy enforcement and Metrological regulations.

The accuracy of thermal conductivity measurements is even more requested for materials characterization in energy-efficient buildings field. ENEA-UTTMATF and CertiMaC research group, as national institute and private laboratory respectively, cooperate in development of new measurement and analysis methods applied to buildings materials and their performances. For what concerns this kind of measurements, an Heat Flow-meter Transducer (HFT) is used. In order to give to both customers and other research institutes involved in the same field (e.g. International Comparison or International Round Robin Tests) the most exhaustive evaluation of the tested material thermal conductivity, a complete uncertainty analysis is implemented on the HFT measures. This uncertainty analysis, developed accordingly to the international standards and with the contribution of INRiM Institute, is described in this paper.

The development of evaluation methods for precision measurement and inter-verification interval measurement for measurement devices based on the concept of the uncertainty of measurement is needed in order to establish the timing of the next scheduled or unscheduled verification of the correspondence of metrological characteristics to their standardised values. The definition of the timing (periodicity) of the metrological verification of measurement devices as used in business or health care, while monitoring environmental conditions and proving health and safety at work, is an urgent issue in scientific research, upon which depends the quality of goods and services. A method of evaluating the accuracy of measurements and the inter-verification interval for measurement devices is proposed, based on using international standards guidelines for quality measurement. The calibration method for evaluating the inter-verification interval of measurement devices was tested during the metrological certification of the measurement device for the moment of inertia of electric motors.

The Guide to the Expression of Uncertainty in Measurement describes a method of evaluating measurement uncertainty that involves attributing an underlying variance to each component of the total measurement error. Assessment of such a variance by statistical methods is known as Type A evaluation of uncertainty, while assessment by any other means is known as Type B evaluation. The involvement of degrees of freedom with Type A evaluation is in accordance with statistical theory. However, the use of “degrees of freedom” with Type B evaluation is an idea primarily developed for practicality, and might be improved upon. That idea ignores the fact that the underlying distribution of the corresponding error will often be assumed to be blunter than normal, as with a uniform distribution, and it can lead to underestimation of the total error variance. Consequently, an alternative concept for Type B evaluation is presented. The resulting analysis fits easily with the use of degrees of freedom in Type A evaluation and leads to an overall method of evaluation that often permits the proper quotation of shorter uncertainty intervals.

Manufactured parts are affected by size and form errors, which need to be assessed against geometrical and dimensional tolerances in order to meet the functional requirements they have been conceived for. The compliance assessment of workpieces with specifications depends on measurements and is unavoidably affected by several uncertainty contributions. According to the geometrical product specifications and verification (GPS), measurement uncertainty consists of method and implementation uncertainty. Literature proposes different approaches for the evaluation of implementation uncertainty, however a standardized method has not been yet achieved. This paper makes an analysis of the various elements to be considered when choosing a specific approach: in the implementation uncertainty of circular features. The most common manufacturing signatures affecting circular profiles were considered, together with the number of points necessary for a reliable estimation of implementation uncertainty.

This paper presents and compares different approaches currently used to assess surface anomalies identified on a product. The common point between these methods is that they are based on a document presented in the form of a table, which is to help the inspector to assess the anomaly detected in a repeatable and reproducible way. We will present three types of table: criteria/level table, tree-like presentation table and an indexed table. As each of these tables presents certain limits when applied to the inspection of a product surface, we will describe the table proposed in order to help the inspector determine the intensity to attribute to the identified anomaly.

Laser trackers are becoming the tool of choice for large volume dimensional metrology applications such as the measurement of aerospace assemblies, power plant structures, civil engineering structures and terrestrial transportation vehicles. A laser tracker is a portable coordinate measuring system that tracks a moving target reflector and measures the position of the target in spherical coordinates (r, θ, φ). The metrological performance of a laser tracker is influenced by many factors including: compensation for atmospheric effects, thermal expansion of the instrument and its mount, thermal distortion of the workpiece or artefact being measured, the wavelength of the laser radiation, the internal alignment of the gimbal axes and the linearity and alignment of the internal angular measuring scales. The most important of these potential error sources, which fundamentally limit the achievable uncertainty, are the internal mechanical and optical alignments and the quality and alignment of the angular scales. Several national and international standards exist or are in the process of being developed for performance verification of laser trackers. ASME B89.4.19-2006 is one of the established standards used to verify the performance of laser trackers. The main test relies on measuring a known reference length in a variety of configurations and ranges and comparison of the observed error (laser tracker measured length minus reference length) with the specified maximum permissible error (MPE) defined by the manufacturer. The establishment of an ASME B89.4.19 laser tracker verification facility at NPL is introduced. We highlight the importance of tracker verification and discuss the error sources, which contribute to the tracker measurement uncertainty. Some initial results obtained using this new facility are presented.

The phase error in a high quality accelerometer was investigated on the basis of systematic experiments on a prototype platform permitting controlled vertical harmonic oscillations. The recordings of an accelerometer and of an ultra-high frequency GPS fixed on this platform were compared with those of a LVDT transducer, controlling the platform movement. All sensors were supported by independent GPS timing. The output of this study is that the recordings of accelerometers are characterized by a random phase error, which, however, decreases with the increase of the oscillation frequency, as dictated from the laws of mechanics. Such errors are important given the increasing use of combinations of accelerometers with various sensors for a wide range of applications. A simple method for the correction of such errors is proposed.

In this paper, we describe techniques for evaluating the uncertainties associated with the assessment of form error, i.e., the departure from ideal geometry of a manufactured part, in coordinate metrology. The techniques take into account measurement uncertainty, sampling effects due to the fact that the form error is determined from a finite set of coordinate data points, and the spatial correlation of the form errors. The techniques are designed to be practical, without the need for complex computation.