Determination of Uncertainties for Correlated Input Quantities by the Monte Carlo Method

This paper presents the calculation of the uncertainty for distribution propagation by the Monte Carlo method for a measurement model with one output quantity. The procedure is shown on the basis of an example of the calculation of a rectangle by direct measurement of length by the same caliper. The measurements are correlated, and the uncertainties are calculated for three values of the correlation coefficients. Another part of the paper presents a validation of the law of propagation of uncertainties for distribution propagation by the Monte Carlo method

Positioner and the procedure for measuring spatial characteristics

The present work focuses on the solution of management of measuring spatial characteristics of security detectors using a positioner, a precision manipulator. It deals with program management software in LabView. Graphical programming with subroutines, which are described as virtual instruments, is used. There are published results of measurements of the spatial characteristics of the PIR detector, where it is preferably used as the measuring station.Ministry of Education, Youth and Sport of the Czech Republic [LO1303 (MSMT-7778/2014)]; European Regional Development Fund under the project CEBIA-Tech [CZ.1.05/2.1.00/03.0089]; Slovak University of Technology in Bratislava; Grant agency APVV [APVV-15-0164]; agency KEGA [KEGA 039STU-4/2017

Meranie vzdialeností za pomoci 3D optického zariadenia pre potreby mobilnej robotiky

This paper presents the collision-free operation of a robotic arm mounted on a mobile robotic unit, using the MS Windows Kinect 3D optical system. The 3D optical system is used for measuring distances and aiding the collision-free manipulation of objects by means of the robotic arm installed on the mobile robotic system (MRS). Attaching of the optical system directly to the robotic arm, essentially, ensures the autonomy of the overall system. The MRS is capable of recognizing the pre-defined objects in the three-dimensional space as well as automatically approaching and manipulating them using the robotic arm. The aim of this article is to present the algorithms used in the MRS to guarantee the collision-free operation of the system. The novelty of our approach lies in the a priori collision avoidance strategy instead of solving collision states as they occur. In addition, the article presents the problem of the localization of the objects in the robot’s surrounding. For this purpose, the balls randomly placed on the floor were localized by the MRS, estimating their real coordinates. Instead of using the standard RGB color space, we propose to utilize the HSV color space in order to enhance the process of objects recognition since the HSV color space provides the more consistent results in the case of varying intensity of the ambient light.Príspevok sa zaoberá bezkolíznou manipuláciou ramena mobilného robota s využitím 3D optického kamerového systému MS Windows Kinect. 3D optický systém slúži pre potreby merania vzdialeností a následnou bezkolíznou manipuláciou s nimi na použitom mobilnom robotickom systéme (MRS), zaujímave je jeho konštrukčné umiestnenie priamo na ramene robota pre zachovanie autómnosti celého systemu. MRS je technologický mobilný robotický demonštrátor, kompletne vyvinutý na našom pracovisku a jeho úlohou je oboznámiť študentov a odbornú verejnosť s možnosťami súčasnej mobilnej robotiky. MRS dokáže rozpoznávať v priestore vopred zadefinované objekty priblížiť sa autonómne k nim a za pomoci robotického ramena bezkolízie aj s nimi manipulovať. V článku budeme riešiť ako boli zadefinované a aplikované konkrétne algoritmy pre garanciu bezkolíznej manipulácie MRS s objektmi, kde na rozdiel od iných prístupov našou snahou je prvotne sa kolízii vyhnuť a nie riešiť stavy ak už kolízia nastane. Riešená bola aj lokalizačná úloha objektov v priestore. Pre potreby riešenia lokalizačných úloh budú v priestore náhodne rozmiestnenené loptičky a úlohou MRS ich bude lokalizovať a stanoviť ich reálne súradnice pre potreby navigačného subsystému MRS. Pre stanovenie pozície nepoužijeme štandardný RGB farebný model, ale HSV farebný model, ktorý dáva lepšie výsledky hlavne pri zmenách intenzity osvetlenia okolného priestoru MRS. Po stanovení reálnych súradníc za pomoci nami zvoleného 3D optického systému, prevedieme záverom štatistický výpočet pre zistenie presnosti nami riešenej lokalizačnej úlohy a výsledných neurčitostí merania v jednotlivých súradných osiach

Matrix Presentation of Uncertainties Propagation in the Realization of ITS-90 Temperature Scale using Standard Platinum Resistance Thermometers

The paper presents a matrix approach to the propagation of uncertainties in the realization of the ITS-90 using Standard Platinum Resistance Thermometers (SPRT) calibrated at Defining Fixed Points (DFPs). The procedure allows correlations to be included between SPRT resistances measured during the calibration at the DFPs (i.e., the realization of the ITS-90) and the resistances measured during the subsequent use of the SPRT to measure temperature T90. The example also shows the possible contribution of these correlations to the overall temperature uncertainty measured by a calibrated SPRT

Application of Metrological Approaches in the Design of Calibration Equipment for Verification of Float Level Gauges

The paper deals with a scientific approach for an increase of accuracy of measurement and possibilities for automation of the standard equipment for calibration and verification of float level gauges. They are applied in high-capacity fuel storage tanks, and they are intended to measure the level of stored liquid hydrocarbons. In the submitted paper, we describe original approaches towards metrological control of float level gauges. Firstly, we present and describe the current ways of control by means of the standard equipment of the first generation with a precision caliper and manual measuring wire with the application of modern scientific and developing processes. A new system, whose design is based on research and development, represents a fully automated measuring system which utilizes the incremental optical encoder with a precision graduated ring and a rewind pulley. The paper deals with the issue of a design of the standard equipment and its measurement system from the standpoint of metrology and construction. Based on scientific procedures, we solve reasons of errors in measurement and their reduction on concrete components of the measurement system. The result is that, following the scientific approach and mathematical description of the determination of measurement uncertainties, constructors are able to design suitable tolerances for the production of components of measuring devices and related materials and technologies

COMPUTATION OF TYPE A UNCERTAINTY FROM THE NORMALLY DISTRIBUTED ORDER STATISTICS

Abstract Metrological characteristics of a measurement instrument to be used in any statistical process control (more about SPC see i

How Can the Check Standard Influence Measurement Process Capability

Purpose: The main objective of the paper is an analysis of the behaviour of capability indices under different conditions. It is assumed that the metrological properties of a check standard are correct, however, the uncertainty of the check standard affects the evaluation of the measurement process capability. The paper analyses individual cases of the influence of the check standard bias and its influence on the measurement process capability. Methodology/Approach: Statistical analysis of both the measurement process and the check standard is provided at the beginning. Development and analysis of possible cases, when the bias of a check standard affects the calculated capability index of a measurement process follows. Findings: The paper confirmed the theoretical assumption that a bias of a check standard can affect the calculated capability index of a measurement process, thus shifting the judgment on the measurement process capability. Research Limitation/Implication: The paper is based on the theoretical assumptions of the measurement process capability as well as on the analysis of the possible behaviour of a respective check standard. Originality/Value of paper: The paper clarifies that several particular and specifically selected cases of bias of a check standard may affect the resulting capability index negatively/positively, which may lead to inaccurate decisions on measurement process capability. This is confirmed by simulations of a biased check standard, clearly visualizing the shifts in capability indices

Application of Monte Carlo Method for Evaluation of Uncertainties of ITS-90 by Standard Platinum Resistance Thermometer

Evaluation of uncertainties of the temperature measurement by standard platinum resistance thermometer calibrated at the defining fixed points according to ITS-90 is a problem that can be solved in different ways. The paper presents a procedure based on the propagation of distributions using the Monte Carlo method. The procedure employs generation of pseudo-random numbers for the input variables of resistances at the defining fixed points, supposing the multivariate Gaussian distribution for input quantities. This allows taking into account the correlations among resistances at the defining fixed points. Assumption of Gaussian probability density function is acceptable, with respect to the several sources of uncertainties of resistances. In the case of uncorrelated resistances at the defining fixed points, the method is applicable to any probability density function. Validation of the law of propagation of uncertainty using the Monte Carlo method is presented on the example of specific data for 25 Ω standard platinum resistance thermometer in the temperature range from 0 to 660 °C. Using this example, we demonstrate suitability of the method by validation of its results

Presnosť polohovania v dvoch osiach

The positional deviation (difference between the actual and target position) belongs to the important criteria that describe the performance of numerically controlled axes. The procedure for determination of such deviation is described in the international standard ISO 230-2:1997. This standard provides calculation of the positional deviation only in several discrete (measuring) points. Moreover it does not consider effects of the measuring instrument on the obtained results. The new methodology is adopted and it is enables estimation of the positional deviation in any point of the axis travel, together with the uncertainty of such estimate. Obtained results can be incorporated into a control system in the form of corrections enhancing positioning possibilities of individual axes. The paper introduces procedures that were verified by measurements for one linear axis. The more complicated situation occurs for testing the positioning accuracy in a plane or in a space respectively. Therefore possible solutions for determination the repeated positioning accuracy in any point of the plane are presented at the end of the paper, together with expression of the respective uncertainty.Odchýlka polohovania (rozdiel medzi skutočnou a požadovanou polohou) patria medzi významné kritéria opisujúce činnosť počítačovo riadených osí strojov. Postup na určenie takejto odchýlky sa uvádza v medzinárodnej norme ISO 230-2:1997. Táto norma poskytuje návod na výpočet odchýlky polohovania iba v niekoľkých diskrétnych bodoch (bodoch merania). Okrem toho neuvažuje vplyv meracieho zariadenia na získané výsledky. Preto sa navrhuje nová metodika, ktorá umožňuje odhad odchýlky polohovania v ľubovoľnom bode na osi, spolu s neistotou takéhoto odhadu. Získané výsledky sa dajú zahrnúť do riadiaceho systému vo forme korekcií umožňujúcich zlepšenie schopnosti polohovania jednotlivých osí. V článku sa uvádzajú postupy, ktoré boli meraniami overené pre jednu lineárnu os. Zložitejšia situácia platí pri testovaní presnosti polohovania v rovine, resp. v priestore. Preto sú na záver uvedené úvahy o možných postupoch pri vyjadrení opakovanej polohovateľnosti aj s neistotami v ľubovoľnom bode roviny