A Virtual Instrument for SEM Uncertainty Analysis

2014 ◽  
Vol 613 ◽  
pp. 101-107
Author(s):  
Dominic Gnieser ◽  
Carl Georg Frase ◽  
Harald Bosse ◽  
Rainer Tutsch
Keyword(s):  
Measurement Uncertainty ◽  
Virtual Instrument ◽  
Metrological Traceability ◽  
Measuring Instrument ◽  
Measurement Instruments ◽  
External Disturbances ◽  
Optical Lens ◽  
Parameters Uncertainty ◽  
Essential Components ◽  
Virtual Measuring Instrument

To assure the metrological traceability of a measurement, it is required to perform an analysis of the measurement uncertainty specific to the measurement task. An approach to estimate the measurement uncertainty for complex systems is the so-called virtual measuring instrument: The measuring process is simulated taking into account its influencing parameters and a statistical analysis is performed by means of Monte-Carlo calculations. We present the development of such a virtual measuring instrument for scanning electron microscopy (SEM) which allows to estimate the measurement uncertainty in compliance with GUM for dimensional measuring tasks in nano- and microsystems technology. By application of this virtual instrument, model based corrections of systematic errors are made possible and the cognition of the strength of different perturbing influences can lead to recommendations to optimize measurement instruments and methods. The virtual model programmed in MATLAB is called ‘vREM’, it includes all essential components of the measuring chain of an SEM as modules: The electron source, the electron-optical lens-system, the scan-generator, the interaction of the electrons within the object, electron detectors, simple analysis procedures and consideration of external disturbances. By adjusting parameters uncertainty contributions can be assigned to the virtual probe, the virtual specimen and the virtual detector signals.

scholarly journals Measuring Pressure Drop Under Non Ideal Conditions

2006 ◽  
Vol 22 (1) ◽  
pp. 6-12
Author(s):  
M Austin
Keyword(s):  
Pressure Drop ◽  
Environmental Effects ◽  
Task Force ◽  
Measurement Procedure ◽  
Measuring Instrument ◽  
Atmospheric Conditions ◽  
Measurement Instruments ◽  
Cigarette Filter ◽  
Calibration Methods ◽  
Method Of Measurement

AbstractThe method of measurement of the pressure drop (PD) of cigarette filter rods and the draw resistance of cigarettes is defined in ISO 6565-2002 (1). This standard defines the calibration and use of a transfer standard to calibrate the measuring instrument and also defines the measurement procedure for cigarette and filter samples. The procedure described in the standard assumes that the measurement conditions are constant and that the sample is in equilibrium with the measurement environment.In 2001, the Cooperation Center for Scientific Research Relative to Tobacco (CORESTA) formed a Task Force to investigate the problems associated with the calibration of PD transfer standards that are caused, primarily, by environmental effects. The work of this task force has lead to the harmonisation of the calibration methods between supplier laboratories and to a method for compensation for the effects of atmospheric conditions. These together have considerably reduced the inter-laboratory differences and will eventually lead to a revision of the CORESTA Recommended Method and ISO 6565 Standard.During the work of this Task Force, it has become evident that further work will be necessary to deal with similar errors encountered during the calibration of PD measurement instruments and during the PD measurement of cigarette and filter rod samples. These errors occur in real measurement situations due to the problems in meeting the ISO 6565 conditions and other necessary requirements. This can give rise to errors in the indicated PD and can considerably degrade the confidence that can be placed in the results.This paper examines many of the practical problems in the measurement of PD and attempts to estimate the type and magnitude of the errors that might be experienced.

scholarly journals Design of Adaptive Sliding Mode Controller for Uncertain Pendulum System

2021 ◽  
Vol 39 (3A) ◽  
pp. 355-369
Author(s):  
Dina H. Tohma ◽  
Ahmed K. Hamoudi
Keyword(s):  
Control Method ◽  
Sliding Mode ◽  
Sliding Mode Controller ◽  
External Disturbances ◽  
Control Effort ◽  
Pendulum System ◽  
Adaptive Sliding Mode ◽  
Adaptive Sliding Mode Controller ◽  
Parameters Uncertainty ◽  
Better Than

This work aims to study and apply the adaptive sliding mode controller (ASMC) for the pendulum system with the existence of the parameters uncertainty, external disturbances, and coulomb friction. The adaptive sliding mode controller has several features over the conventional sliding mode control method. Firstly, the magnitude of the control signal is reduced to the minimally acceptable level defined by special conditions concerned with ASMC algorithm. Secondly, the upper bounds of uncertainties are not necessary to be defined before starting the work. For this reason, the ASMC can be used successfully to control the pendulum system with minimum control effort. These properties of the ASMC are confirming graphically by the simulation results using MATLAB 2019. The ASMC achieves an asymptotically stable system better than the Classical Sliding Mode Controller (CSMC). The unwanted phenomenon is called “chattering", which is appearing in the control action signal. These drawback properties are suppressed by employing a saturation function. Finally, the comparison between the results of the ASMC and CSMC showed that ASMC is the better one.

Remarks to Calibration in Chemistry

2012 ◽  
Vol 2 (1) ◽  
pp. 67-76
Author(s):  
Viliam Patoprsty ◽  
Miroslava Valkova
Keyword(s):  
Reference Material ◽  
Measurement Method ◽  
Certified Reference Materials ◽  
Metrological Traceability ◽  
Indirect Measurement ◽  
Measuring Instrument ◽  
Real Situation ◽  
Stated Reference ◽  
The Relationship ◽  
Crm Certification

Calibration is the operation establishing metrological traceability of values of calibrated measuring instrument scale (or reference material) to stated reference. In the case of indirect measurement it is necessary to know the relationship between determined quantity values and corresponding measurand values. If mathematic form of this relationship is unknown, it is substituted by its approximation. In this process a real situation is simplified by neglecting of influence quantities to a relation of two variables- independent versus dependent. Metrological traceability of certified reference materials (CRM) values intended for calibration purposes and characterised by means of a method working on the base of approximative function could be questionable. If a measurement method based on original relationship already exists, it should be strongly preferred in the process of CRM certification to methods based on approximation of original relationship.

scholarly journals Non-adaptive velocity tracking controller for a class of vehicles

2017 ◽  
Vol 65 (4) ◽  
pp. 459-468 ◽  
Author(s):  
P. Herman ◽  
W. Adamski
Keyword(s):  
Control Algorithm ◽  
Equations Of Motion ◽  
Adaptive Controller ◽  
Underwater Vehicles ◽  
Low Velocity ◽  
External Disturbances ◽  
Parameters Uncertainty ◽  
Tracking Controller ◽  
The Stability ◽  
Velocity Tracking

AbstractA non-adaptive controller for a class of vehicles is proposed in this paper. The velocity tracking controller is expressed in terms of the transformed equations of motion in which the obtained inertia matrix is diagonal. The control algorithm takes into account the dynamics of the system, which is included into the velocity gain matrix, and it can be applied for fully actuated vehicles. The considered class of systems includes underwater vehicles, fully actuated hovercrafts, and indoor airship moving with low velocity (below 3 m/s) and under assumption that the external disturbances are weak. The stability of the system under the designed controller is demonstrated by means of a Lyapunov-based argument. Some advantages arising from the use of the controller as well as the robustness to parameters uncertainty are also considered. The performance of the proposed controller is validated via simulation on a 6 DOF robotic indoor airship as well as for underwater vehicle model.

scholarly journals Precise linear measurements using a calibrated reference workpiece without temperature measurements

2018 ◽  
Vol 7 (2) ◽  
pp. 609-620 ◽  
Author(s):  
Dmytro Sumin ◽  
Rainer Tutsch
Keyword(s):  
Thermal Expansion ◽  
Measurement Uncertainty ◽  
Temperature Measurements ◽  
Coordinate Measuring Machines ◽  
Measuring Instrument ◽  
Linear Measurements ◽  
Linear Measuring ◽  
Require Temperature ◽  
Linear Measuring Instrument

Abstract. We suggest a procedure for the correction of the errors caused by thermal expansion of a workpiece and the scale of a linear measuring instrument (coordinate measuring machines, length measuring machines, etc.) when linear measurements are performed at nonstandard temperature. We use a calibrated reference workpiece but do not require temperature measurements. An estimation of the measurement uncertainty and application examples are given.

scholarly journals AC/DC transfer standards calibration in Central Military Calibration Laboratory

2017 ◽  
Vol 66 (4) ◽  
pp. 217-228
Author(s):  
Przemysław Piróg ◽  
Mariusz Górecki
Keyword(s):  
Measurement Uncertainty ◽  
Metrological Traceability ◽  
Uncertainty Budget ◽  
Voltage Measurement ◽  
Measurement Equation ◽  
Calibration Laboratory ◽  
Transfer Standard ◽  
Thermal Voltage

The article discusses the method used in the Central Military Calibration Laboratory to calibrate Fluke 5790 AC/DC transfer standard with reference transfer standard Fluke 792A. It presents the measurement equation and the uncertainty budget. The contribution of uncertainty components in the measurement uncertainty has been presented. The metrological traceability has been evaluated by comparing calibration results with the results in the last Fluke certificate of calibration. Keywords: AC/DC converters, AC/DC difference, thermal voltage converters (TVCs), AC voltage measurement.

scholarly journals Evaluation and Optimization of Task-oriented Measurement Uncertainty for Coordinate Measuring Machines Based on Geometrical Product Specifications

2018 ◽  
Vol 9 (1) ◽  
pp. 6 ◽  
Author(s):  
Yinbao Cheng ◽  
Zhongyu Wang ◽  
Xiaohuai Chen ◽  
Yaru Li ◽  
Hongyang Li ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Evaluation Model ◽  
Optimization Method ◽  
Practical Significance ◽  
Measuring Instruments ◽  
Coordinate Measuring Machines ◽  
Measurement Instruments ◽  
Practical Applications ◽  
Geometric Product ◽  
Task Oriented

Measuring instruments are intended to be intelligent, precise, multi-functional and developing multidirectionally, scientific, and reasonable; the reliable evaluation of measurement uncertainty of precision instruments is also becoming more and more difficult, and the evaluation of the Coordinate Measuring Machines (CMM) measurement uncertainty is among the typical problems. Based on Geometric Product Specification (GPS), this paper has systematically studied the CMM uncertainty for evaluating the size and geometrical errors oriented toward measurement tasks, and thus has realized the rapid and reliable evaluation of the CMM uncertainty for task-oriented measurement. For overestimation of the CMM uncertainty for task-oriented measurements in the initial evaluation, a systematic optimization solution has been proposed. Finally, the feasibility and validity of the evaluation model and the optimization method have been verified by three different types of measurement examples of diameter, flatness and perpendicularity. It is typical and representative to systematically solve the problem of the CMM uncertainty for evaluating the measurement tasks targeted at dimensions and geometric errors, and the research contents can be effectively applied to solve the uncertainty evaluation problems of other precision instruments, which are of great practical significance not only for promoting the combination of modern uncertainty theory and practical applications but also for improving the application values of precision measurement instruments.

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