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1

A New Laser-Registered View of the Shrinkage Kinetics of Foundry Alloys

Zych J., Snopkiewicz T.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 3

41--46

EN

This paper presents a new stand for studying the linear shrinkage kinetics of foundry alloys. The stand is equipped with a laser displacement sensor. Thanks to this arrangement, the measurement is of a contactless nature. This solution allows for the elimination of errors which occur in measurements made using intermediary elements (steel rods). The supposition of the expansion (shrinkage) of the sample and the expansion of the heated rod lead to the distortion of the image of the actual dimensional changes of the studied sample. A series of studies of foundry alloys conducted using the new stand allowed a new image of shrinkage kinetics to be obtained, in particular regarding cast iron. The authors introduce in the study methodology a real-time measurement of two linked quantities; shrinkage (the displacement of the free end of the sample) and temperature in the surface layer of the sample casting. This generates not only a classic image of shrinkage (S) understood as S = f (t), but also the view S = f (T). The latter correlation, developed based on results obtained using the contactless method, provide a new, so far poorly known image of the course of shrinkage in foundry alloys, especially cast iron with graphite in the structure. The study made use of hypo- and hypereutectic cast iron in order to generate an image of the differences which occur in the kinetics of shrinkage (as well as in pre-shrinkage expansion - expansion occurs during solidification).

2

3D Modelling of Cylindrical-Shaped Objects From Lidar Data - an Assessment Based on Theoretical Modelling and Experimental Data

Janowski A., Bobkowska K., Szulwic J.

Metrology and Measurement Systems

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2018

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Vol. 25, nr 1

47--56

EN

Despite the increasing availability of measured laser scanning data and their widespread use, there is still the problem of rapid and correct numerical interpretation of results. This is due to the large number of observations that carry similar information. Therefore, it is necessary to extract from the results only the essential features of the modelled objects. Usually, it is based on a process using filtration, followed by simplification and generalization of redundant contents of datasets. This process must ensure the collection of new data without loss of information contained therein, the description accuracy of the key features of a measured object, as well as the uniqueness and comparability of results. In this paper, the authors extend the already extensive range of algorithms for the automatic or semiautomatic modelling of cylindrical objects, which have been measured using the laser scanning technology, with the one employing a concave hull or - in general - the alpha-shape (α-shape). The applicability of the proposed method was analysed using simulated data - generated analytically with the introduced and established systematic error with normal distribution - and using real results of the measurement of cylindrical-shaped objects. For real data, the obtained results were compared with the reference data. This made it possible to determine the validity of the proposed new method.

3

The analysis of signal disruptions from an optical triangulation measurement sensor

Stryczek R., Dutka P.

Measurement Automation Monitoring

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2016

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Vol. 62, No. 2

62--65

EN

The paper presents the analysis of a measurement signal from a measurement triangulation sensor (laser) obtained during the positioning of an industrial robot. The signal is characterised by the range of disruptions. Their character is complex, because it involves the influence of robot position correction signals generated by the drive, free vibrations of the mechanical system caused by its movement and instability of reading the optical measurement sensor. There are presented the components of a test stand as well as the interactions between the robot control system, PLC, the laser controller and the user's HMI. The results of the analysis of the obtained data indicate that the reliable reading in the time shorter than the time of the system relaxation is possible. The presented issue is an element of a wider research program, the aim of which is to determine the correlations between the measurement capability of the method realised with the active use of an industrial robot and the measurement realisation time.

4

Application Of Kalman Filter In Navigation Process Of Automated Guided Vehicles

Śmieszek M., Dobrzańska M.

Metrology and Measurement Systems

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2015

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Vol. 22, nr 3

443--454

EN

In the paper an example of application of the Kalman filtering in the navigation process of automatically guided vehicles was presented. The basis for determining the position of automatically guided vehicles is odometry – the navigation calculation. This method of determining the position of a vehicle is affected by many errors. In order to eliminate these errors, in modern vehicles additional systems to increase accuracy in determining the position of a vehicle are used. In the latest navigation systems during route and position adjustments the probabilistic methods are used. The most frequently applied are Kalman filters.

5

Laserowe metody oceny struktury geometrycznej powierzchni

Łukianowicz C., Kapłonek W.

Stal, Metale & Nowe Technologie

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2014

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nr 7-8

26--27

PL

W artykule przedstawiono podstawy oceny struktury geometrycznej powierzchni z zastosowaniem metod laserowych. Przedstawiono ogólną charakterystykę tych metod, a nieco szerzej opisano wybrane metody oparte na zastosowaniu zjawiska rozpraszania promieniowania laserowego. Metody te pozwalają w sposób szybki i bezstykowy dokonywać oceny nierówności powierzchni i z powodzeniem mogą być zastosowane w warunkach produkcyjnych.

EN

In the paper the principles of the surface texture assessment by laser methods have been presented. The general characteristics of these methods have been presented, and selected methods based onlight scattering phenomenon have been expanded. These methods allow for arapid and non-contact assessment of the surface roughness and can be successfully used in production conditions.

6

Badania drgań silników wrzecionowych pamięci masowych

Kołton W., Trawiński T.

Przegląd Elektrotechniczny

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2011

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R. 87, nr 12b

188--191

PL

W niniejszym artykule przedstawiono konstrukcję prototypowego stanowiska badawczego przeznaczonego dla badań drgań silników wrzecionowych stosowanych we współczesnych pamięciach masowych (dyskach twardych). Przedstawiono wyniki badań drgań silnika wrzecionowego wyposażonego w łożyska hydrodynamiczne oraz łożyska kulkowe.

EN

In this article the prototype of laboratory test bench devoted to research of vibration of spindle motor used in modern mass storage devices (hard disk drives) is presented. Exemplary results of vibration investigation of spindle motor equipped with hydrodynamic and ball bearings are shown.

7

Propagation of laser light in the moving air

Pieszyński K., Rożniakowski K., Klemm K., Klemm P.

Scientific Bulletin. Physics / Lodz University of Technology

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2005

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Vol. 25

47-52

EN

The paper presents theoretical analysis and experimental results which show the possibility of the application of laser beam in examination of the changes of physical parameters of the air flow disturbed by the presence of solid objects.

PL

W pracy przedstawiono analizę teoretyczną i wyniki eksperymentalne pokazujące możliwości wykorzystania wiązki lasera do analizy zmian parametrów fizycznych przepływającego powietrza, spowodowanych obecnością obiektów wprowadzających zaburzenia tego przepływu.

8

Detection of Early Stages of Pinion Tooth Chipping in Transmission Gear

Łazarz B., Wojnar G.

Machine Dynamics Problems

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2003

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Vol. 27, No. 3

23-34

EN

This paper presents carried out laboratory tests, which were aimed at detecting early stages of chipping of the pinion tooth crest by measurement and analysis of transverse vibration speed of transmission gear shafts. During co-operation of defected gear wheels, a local unsteadiness appeared in the generated vibration signal, and therefore a continuous wavelet transform was employed to its processing. A group of wavelets useful in diagnostics of pinion tooth chipping was selected as well as the measure for tooth chipping proportional to the size of chipping was proposed.