Valery A. Granovskiy, Tatiana N. Siraya,
SYSTEMATIC ERRORS: METHODOLOGY OF DETECTION, ELIMINATION, AND EVALUATION

The main objects and methods of systematic error theory are presented. The basic notion of systematic error is analysed, in connection with the main stages of the measurement procedure. The main problems of detection, elimination, evaluation, and estimation of systematic errors are outlined. Interrelation of the systematic and random errors is also considered.

J. A. Sousa, I. M. Smith, A. B. Forbes, A. S. Ribeiro, D. F. Sousa
EVALUATION OF MEASUREMENT UNCERTAINTY IN TESTS REQUIRING NON-LINEAR REGRESSION

This work is concerned with the evaluation of measurement uncertainty arising from the use of non-linear regression in testing. While modern standards require a measured value to be accompanied by a statement of its quality in the form of an associated uncertainty, for many applications existing work procedures make no reference to uncertainty. Such procedures should therefore be updated to take account of the requirement to provide uncertainty information. This paper considers an application that involves the use of non-linear regression and for which uncertainty evaluation does not constitute part of the current work procedure. An updated procedure is proposed and example results are presented.

K. Konkarikoski
ASPECTS OF MEASUREMENT POLICY WITH UNCERTAIN MEASUREMENTS

This paper describes how to use uncertain measurements in decision making. How to verify measurement policy with uncertainty involved. Simulation of process behavior with different uncertainties and cost structures are tackled. An example with four different decision options is shown and process of simulation is explained and visualized.

M. L. C. C. Reis, J. B. P. Falcão Filho, B. Goffert, L. F. G. Moraes
EVALUATION OF MACH NUMBER DISTRIBUTION AT THE TEST SECTION OF THE TTP TRANSONIC WIND TUNNEL

The distribution of the Mach number at the test section of the Brazilian Pilot Transonic Wind Tunnel is under evaluation for the subsonic, transonic and low supersonic ranges. The measured parameters in these investigative tests are static and total pressure of the airflow, which are the input quantities for the isentropic equation used for the Mach number estimation, which is the output quantity. The measurement of static pressures at several stations of the test section is accomplished by positioning a pressure probe at the centreline and by distributing pressure taps along the superior and inferior walls. The total pressure is measured at two locations: at the stilling chamber of the circuit and at the tip of the probe. Data reduction includes the evaluation of the uncertainties associated with the measured quantities, as well as their propagation to the output quantity, employing the Monte Carlo method. Least squares fitting is applied to the experimental data in order to supply Mach number distribution as a function of longitudinal positions of the test section. The distribution at the centreline resulting from the tests is compared to Computational Fluid Dynamics simulation for the supersonic regime.

B. Aschenbrenner, B. G. Zagar
DSP BASED READ OUT SYSTEM FOR CONTACTLESS HIGH-FREQUENCY INDUCTIVE POSITION SENSORS

This paper presents a precise and low cost absolute position inductive measurement system for rough industrial environments. This transducer works on similar principles as contactless resolvers but consists of a rectangular antenna PCB, a passive LC resonance target and a signal processing unit. The read out electronics utilize undersampling to demodulate the transducer in{phase and quadrature output signals. Furthermore, the corresponding position is estimated from a lookup table (LUT) to avoid singularities in the inverse tangent and cotangent calculation. The mechanical transducer arrangement, signal condition electronics design and measured results will be presented.