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 fornon-destructive testing and has nowadays become a revolutionary tool for dimensionalmetrology, suitable for actual/nominal comparison and verification of geometrical anddimensional tolerances. This paper evaluates measurement results using different measuringstrategies applied in different inspection software packages for volume and surface dataanalysis. The strategy influence is determined by calculating the measurement uncertainty.This investigation includes measurements of two industrial items, an aluminium pipeconnector and a plastic toggle, a hearing aid component. These are measured using acommercial CT scanner. Traceability is transferred using tactile and optical coordinatemeasuring machines, which are used to produce reference measurements. Results show thatmeasurements of diameter for both parts resulted in smaller systematic errors compared todistance and height measurements. It was found that uncertainties of all measurandsevaluated on surface data were generally greater compared to measurements performed onvolume data.

There have been substantial improvements in measurement systems in order to meetfluctuating market demands. This rapid change and development in measurement technologyhas 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 fulfillingcustomer demands for more than a decade. Though, current CMMs can meet needs of rapid andincreased demands of customers to a greater extent but still there is lot of scope forimprovement and development in CMMs. The globalization of manufacturing has resulted indevelopment 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 complexitiesof parts and micro & nano range products has to be investigated. In this paper,comprehensive review concerning CMMs with capabilities to measure micro/nano features hasbeen presented. This work has also discussed different methods to estimate measurementuncertainty, as well as performance evaluation of CMMs. Moreover, novel concepts such asintelligent CMM, multi-sensor CMM, virtual CMM have been presented.

This article proposes a combined theoretical and experimental approach to assess andquantify the global uncertainty of a high-speed camera velocity measurement. The study isdivided in five sections: firstly, different sources of measurement uncertaintiesperformed by a high-speed camera are identified and quantified. They consist ofgeometrical uncertainties, pixel discretisation uncertainties or optical uncertainties.Secondly, a global uncertainty factor, taking into account the previously identifiedsources of uncertainties, is computed. Thirdly, a sensibility study of the camera set-upparameters is performed, allowing the experimenter to optimize these parameters in orderto minimize the final uncertainties. Fourthly, the theoretical computed uncertainty iscompared with experimental measurements. Good concordance has been found. Finally, thevelocity measurement uncertainty study is extended to continuous displacement measurementsas a function of time. The purpose of this article is to propose all the mathematicaltools necessary to quantify the individual and global uncertainties, to highlight theimportant aspects of the experimental set-up, and to give recommendations on how toimprove a specific set-up in order to minimize the global uncertainty. Taking all theseinto account, it has been shown that highly dynamic phenomena such as a ballisticphenomenon can be measured using a high-speed camera with a global uncertainty of lessthan 2%.

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.

Optical and tactile single scanning probes usually are used in dimensional metrologyapplications, especially for roughness, form, thickness and surface profile measurements.To perform assessments with nanometre level of accuracy, specific ultra-high precisionmachines have been developed by the National Metrology Institutes (NMIs) such as the LNE,VSL, METAS, SMD, generally in collaboration with industrials and academics partners. Suchdevelopments are not devoted only to NMIs but many industrials develop and commercializetheir own ultra-high precision machines as the IBSPE and TNO companies. All these machinesprovide optical and tactile precise measurements and cover a large domain of applicationsuch as the form’s characterization of optical lenses. In this paper the performance andcapability of ultra-high precision machines of some National Metrology Institutes (LNE,VSL, SMD and METAS) and industrials companies (TNO and IBSPE), involving together in theIND10 European EMRP project titled “Optical and tactile metrology for absolute formcharacterization”, will be detailed. Theirs probing systems and accuracies levels will beevoked. Relevant results especially for measuring optical lenses will be also presentedand discussed.

The paper gives a brief description of the principles and the uncertainty of the acousticcalibration methods that today are applied by National Metrology Institutes andcalibration service centers. Even if some of the calibration principles have been appliedover more than half a century, the methods and the instrumentation are still being refinedin order to minimize their uncertainty, to extend their frequency ranges, to include extraparameters and to speed up slow processes. In addition to the traditional methods formicrophone sensitivity and frequency response calibration, new development areas, like forexample wind power, has created needs for low-frequency and infra-sound calibration, downto 0.1 Hz. Other high-tech areas have lead to the development of methods for phaseresponse comparison calibration of microphones for large arrays, for sound intensitymeasurement and for verification of dynamic linearity of microphones at very high soundpressure levels, up to about 174 dB that corresponds to 10 kPa.

In the building domain, components or equipment are often subjected to severeenvironmental conditions. In order to predict the reliability and the life-time of suchequipment, accelerated life testing can be carried out. Severe conditions are applied toaccelerate the ageing of the components and the reliability at nominal conditions is thendeduced considering that these nominal conditions are not constant but stochastic. In thispaper, the accelerated life testing of photovoltaic modules is carried out at severemodule temperature levels. The module power losses are monitored and the limit state isdetermined when a threshold power is reached. The stochastic data and the reliability aresimulated during a period of twenty years. Finally, the life time of the component isevaluated.

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

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.

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

Manufactured parts are affected by size and form errors, which need to be assessedagainst geometrical and dimensional tolerances in order to meet the functionalrequirements they have been conceived for. The compliance assessment of workpieces withspecifications depends on measurements and is unavoidably affected by several uncertaintycontributions. According to the geometrical product specifications and verification (GPS),measurement uncertainty consists of method and implementation uncertainty. Literatureproposes different approaches for the evaluation of implementation uncertainty, however astandardized method has not been yet achieved. This paper makes an analysis of the variouselements to be considered when choosing a specific approach: in the implementationuncertainty of circular features. The most common manufacturing signatures affectingcircular profiles were considered, together with the number of points necessary for areliable estimation of implementation uncertainty.

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

The accuracy of thermal conductivity measurements is even more requested for materialscharacterization in energy-efficient buildings field. ENEA-UTTMATF and CertiMaC researchgroup, as national institute and private laboratory respectively, cooperate in developmentof new measurement and analysis methods applied to buildings materials and theirperformances. 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 involvedin the same field (e.g. International Comparison or International Round Robin Tests) themost exhaustive evaluation of the tested material thermal conductivity, a completeuncertainty analysis is implemented on the HFT measures. This uncertainty analysis,developed accordingly to the international standards and with the contribution of INRiMInstitute, is described in this paper.

Laser trackers are becoming the tool of choice for large volume dimensional metrologyapplications such as the measurement of aerospace assemblies, power plant structures,civil engineering structures and terrestrial transportation vehicles. A laser tracker is aportable coordinate measuring system that tracks a moving target reflector and measuresthe position of the target in spherical coordinates (r,θ, φ). The metrological performance of a laser trackeris influenced by many factors including: compensation for atmospheric effects, thermalexpansion of the instrument and its mount, thermal distortion of the workpiece or artefactbeing measured, the wavelength of the laser radiation, the internal alignment of thegimbal axes and the linearity and alignment of the internal angular measuring scales. Themost important of these potential error sources, which fundamentally limit the achievableuncertainty, are the internal mechanical and optical alignments and the quality andalignment of the angular scales. Several national and international standards exist or arein the process of being developed for performance verification of laser trackers. ASMEB89.4.19-2006 is one of the established standards used to verify the performance of lasertrackers. The main test relies on measuring a known reference length in a variety ofconfigurations and ranges and comparison of the observed error (laser tracker measuredlength minus reference length) with the specified maximum permissible error (MPE) definedby the manufacturer. The establishment of an ASME B89.4.19 laser tracker verificationfacility at NPL is introduced. We highlight the importance of tracker verification anddiscuss the error sources, which contribute to the tracker measurement uncertainty. Someinitial results obtained using this new facility are presented.

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.

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.

This paper reports work carried out to determine the influence of the Pyramidal indenter geometrical errors and tolerances on the accuracy of Vickers hardness measurements. The angle between the opposite faces and line of conjunction of nine indenters were measured by the optical comparator. The influence of the indenter geometry on the hardness accuracy is investigated. Three calibrated reference hardness test blocks were used to check the Vickers hardness test using the nine selected indenters. The results show that the geometrical error of the indenters (specially the angles) considerably affects the accuracy of the hardness measurement. Finite element analysis of the indentation process into metallic test pieces was conducted. Comparison of the experimental results with the numerical findings was discussed. Errors in the experimental values are correlated with measured tolerances in the angles between faces.

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.