IMEKO Event Proceedings Search

   

Page 656 of 977 Results 6551 - 6560 of 9762

P. Rattanangkul, C. Hirunyapruk, B.Thummawut, V. Plangsangmas
THE BILATERAL COMPARISON FOR CHARGE SENSITIVITY OF STANDARD ACCELEROMETER BETWEEN OLD SYSTEM AND NEW SYSTEM AT NIMT

National Institute of Metrology (Thailand), NIMT has two primary accelerometer calibration systems, old and new systems, using methods according to ISO16063-11. The differences between both systems are the calibration methods and the moving direction of exciter. This paper presents the comparison for charge sensitivity of standard accelerometer between two systems in order to investigate the effects of calibration methods and moving direction of exciter on the calibration results, to confirm the capability of the new system and to provide a link between two systems. Also the comparison results at the frequency range of 40 to 5,000 Hz are illustrated.

C. Hirunyapruk, P. Rattanangkul, B. Thummawut, V. Plangsangmas
A CALIBRATION SYSTEM FOR LASER VIBROMETERS AT NIMT

Laser Vibrometers have been used in many applications such as automotive and hard disk drive industries. In metrological field, laser vibrometers are employed as reference standards for the calibration of accelerometers. To have the traceability chain to the International System of Units (SI), several National metrological institutes (NMIs) and companies have developed calibration systems for laser vibrometers. National Institute of Metrology (Thailand), NIMT, is one of those NMIs. This paper describes the set-up for the primary vibrometer calibration system used at NIMT and presents the methods used according to methods 1 and 2 shown in the international standard ISO16063-41. The calibration results are also discussed.

Alistair B. Forbes, Hoang D. Minh
OPTIMAL DESIGN FOR LINEAR CALIBRATION PROBLEMS

This paper considers the design of instrument calibration experiments with the focus of minimising the uncertainties associated with the use of the instrument. For this problem, the optimal design depends on the actual response of the system and so cannot be implemented without prior information about the actual response. We consider a number of approaches.

E. Garcia, T. Hausotte, A. Amthor
BAYES FILTER FOR IMPROVING AND FUSING DYNAMIC COORDINATE MEASUREMENTS

This paper presents a novel methodology to improve the measurement accuracy of dynamic measurements. This is achieved by deducing an online Bayes optimal estimate of the true measurand given uncertain, noisy or incomplete measurements within the framework of sequential Monte Carlo methods. The estimation problem is formulated as a general Bayesian inference problem for nonlinear dynamic systems. The optimal estimate is represented by probability density functions, which enable an online, probabilistic data fusion as well as measurement uncertainty evaluation completely conform to the "Guide to the expression of uncertainty in measurement". The efficiency and performance of the proposed methodology is verified and shown by dynamic coordinate measurements.

Tran Trung Nguyen, Christian Tolks, Arvid Amthor, Christoph Ament
SIMULATION OF VARIOUS ARRANGEMENTS FOR THE MULTI LASER TRACKER SYSTEM

This paper presents a Monte Carlo simulation of the self-calibration for the multi laser tracker system (MLTS) which can track a retro-reflector mounted on the kinematical system (e.g. positioning stage, robot manipulator etc.). Four laser trackers build up the MLTS. In the first part of the study the required algorithms enabling the MLTS to measure the position of the retro-reflector are presented. The algorithms include the localization of the retro-reflector, the communication between the laser trackers, the tracking controller and the calculation of the Tool Centre Point (TCP) position. In the second part of this study a deeper analysis of the self-calibration algorithm is carried out. A Monte Carlo simulation shows that the quality of the parameter estimation highly depends on the optimal arrangement of the MTLS.

E. Reetz, A. Schlegel, P. Werner, G. Linß
STRAIGHT LINE DETECTION FOR AUTOMATED MEASUREMENT IN IMAGE SCENES

When dealing with point cloud data retrieved from optical coordinate measurement machines, a spline filter scale space method as proposed in [1] is applied to contour decomposition problems for automated measurement of geometric primitives/features. The object contour will be split into a more simple structure, using the spline filter scale space to detect corner regions along the contour. This article explains an approach to increase the segmentation results for straight line segments, based on point cloud data only.

F. Härtig, K. Kniel
VALUABLE ADVICES ON COMPARISON RULES FOR UNAMBIGUOUS EVALUATION OF MEASUREMENT RESULTS

International comparison measurements are the backbone for validating the competence of metrology institutes among one another. An informative interpretation of the results requires, however, intensive studies of the individual reports and great expertise of the readers. This is due to the lack of a clear procedure for the assessment of such comparison measurements which leads to different values which are difficult to compare. The selection of the reference value formation is, for example, open. Likewise, an equivalence value, the normalized error value (En value) – which is usual for comparisons – can be calculated on the basis of the standard measurement uncertainty or on the basis of the expanded measurement uncertainty. The third degree of freedom relates to the elimination of outliers which is handled in different ways. A decision of how a participant contributes to the reference value, or whether his measurement results are regarded as comparable, may – depending on the calculation carried out – one time turn out in his favour and another time to his disadvantage. Studies of international comparison measurements from the field of length show – as examples – that the different procedures applied in comparison measurements are commonplace. In addition to the usual assessment possibilities, examples are shown which clearly show the problems. With the example of gear measurement, a proposal is presented of how comparison measurements should in future be carried out clearly and transparently.

R. Hamaguchi, Y. Tsutsumi, H. Kawamura, T. Suzuki
A NOTE ON APPLICATION OF MEASUREMENT PRECISION FOR BINARY DATA

This paper describes the previous works about the precision for binary data, and clarifies about a view of those methods and what kind of feature. Furthermore, propose that the method of estimating precision from ANOVA using the normal approximation by logit transformation. We compare each method, and consider the relation between methods from the result.

Tomomichi Suzuki, Yusuke Tsutsumi, Ryosuke Hamaguchi, Hironobu Kawamura
RECENT DEVELOPMENTS IN PRECISION EVALUATION IN NON-QUANTITATIVE MEASUREMENTS

This paper describes the recent developments in precision evaluation in non-quantitative measurements. Precision evaluation in quantitative measurements is a thoroughly discussed topic and the established methods are in use. Many methods are proposed for qualitative data, but their effectiveness and statistical properties are not so clear. This paper introduces, compares and discusses the methods to evaluate precision for qualitative data.

Raghu Kacker, D. Richard Kuhn, Yu Lei, James Lawrence
COMBINATORIAL TESTING FOR SOFTWARE USED IN METROLOGY

Most modern instruments of measurement for science, engineering, and commerce have embedded software. Also, software is required for mathematical computations. Therefore testing, verification, and validation of software used in metrology is important. Combinatorial testing is a versatile methodology which could be useful for many testing situations. It is based on the insight that while the behaviour of a software system may be affected by a large number of factors, only a few factors are involved in a failure inducing fault. This paper is an introduction to combinatorial testing as an adaptation of design of experiment methods for testing software.

Page 656 of 977 Results 6551 - 6560 of 9762