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Merezhany A., Antonyuk V. Genetic Algorithms Application For The Computer-Aided Design Engineering Of Mechanical Treatment Of Details

Saturday, 12 November 2011 15:06 administrator
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Merezhany A., Antonyuk V. Genetic Algorithms Application For The Computer-Aided Design Engineering Of Mechanical Treatment Of Details. - Научно-теоретический и практический журнал "ОРАЛДЫН FЫЛЫМ ЖАРШЫСЫ" - № 1 (28) 2011.

This research examines the questions of genetic algorithms implementation for CAD EP of mechanical treatment in instrument and machine engineering. The advantages of genetic algorithms over existing tecniques of the computer-aided design are adduced. Analysis and choice of an optimization criterion of engineering processes are given.

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Last Updated on Saturday, 12 November 2011 15:08
 

Molebny V., Chyzh I., Sokurenko V., Molebny S, Pallikaris I., Naoumidis L. Phase-transparency model of an eye optical system

Friday, 22 July 2011 18:24 administrator
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Measurement of refraction distribution in the human eye opens new opportunities to make photorefractive surgery more accurate due to accounting imperfections not only of the cornea, but of the eye as an optical system. To calculate the to-be-ablated cornea layers, mathematical relations must be found between measured coordinates of retina ray tracings and transfer function of an eye. A new concept for modelling eye optical system is proposed using four phase transparencies, each of them exercising its own function: accommodation (equivalent to varifocal system), image focusing on the retina (optical system with constant optical power), regular aberrations (spherical and chromatic, astigmatism), and irregular phase distribution. It is shown, how the parameters, necessary for phase transparencies description, can be derived from direct and indirect measurements. Results of modelling experiment with simplified set of test points showed good sight correction. Investigated methodology proved to be fruitful even with limited number of test points and restricted length of polynomial approximation. In our refraction mapping system, transfer function reconstruction will use initial information from 65 points.
Keywords: eye model, phase transparency, retina ray tracing technique.

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Molebny V., Chyzh I., Sokurenko V., Pallikaris I., Naoumidis L. Eye aberrations analysis with Zernike polynomials

Friday, 22 July 2011 18:27 administrator
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New horizons for accurate photorefractive sight correction, afforded by novel flying spot technologies, require adequate measurements of photorefractive properties of an eye. Proposed techniques of eye refraction mapping present results of measurements for finite number of points of eye aperture, requiring to approximate these data by 3D surface. A technique of wave front approximation with Zernike polynomials is described, using optimization of the number of polynomial coefficients. Criterion of optimization is the nearest proximity of the resulted continuous surface to the values calculated for given discrete points. Methodology includes statistical evaluation of minimal root mean square deviation (RMSD) of transverse aberrations, in particular, varying consecutively the values of maximal coefficient indices of Zernike polynomials, recalculating the coefficients, and computing the value of RMSD. Optimization is finished at minimal value of RMSD. Formulas are given for computing ametropia, size of the spot of light on retina, caused by spherical aberration, coma, and astigmatism. Results are illustrated by experimental data, that could be of interest for other applications, where detailed evaluation of eye parameters is needed.
Keywords: eye aberrations, sight correction, photorefractive operations, eye refraction map, refraction non-homogeneity, Zernike polynomials, eye refraction measurement.

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Molebny V., Pallikaris I., Naoumidis L., Chyzh I., Molebny S., Sokurenko V. Retina ray-tracing technique for eye-refraction mapping

Friday, 22 July 2011 20:24 administrator
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In photorefractive sight correction, pre-operational computations of to-be-ablated layers are usually based on information about cornea shape that is one of the causes of aberrations. To obtain high-quality results of operation, contributions to aberrations of other origins are to be taken into account. Technique of eye-aberration mapping has been investigated, we called retina ray-tracing. It consists in directing into the eye a narrow beam, scanned (translated) in parallel to itself. Computer controls trajectory of scanning. Beam projection (spot of light) is formed on the retina. Aberrations result in varying position of the spot on retina in the course of scanning. Deviations from initial position are measured and reconstructed into wave aberration function. Mathematical relations, using Zernike polynomial expansions, were found to transform these data into necessary cornea shape correction with ablation technologies. In our experimental setup, we used the technique of acousto-optic scanning with frame time less than 10 ms for 65 sensed points. Eye-aberration mapping is realized with optical power resolution 0.1 diopter.
Key words: photorefractive sight correction, retina ray-tracing, acousto-optic scanning, Zernike polynomials, ablation technology, eye-aberration mapping, wave aberration function.

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Ostafiev V.A., Noshchenko A. N. Thermostrength of Carbide Tools

Sunday, 13 November 2011 20:26 administrator
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V. A. Ostafiev , A. N. Noshchenko. Thermostrength of Carbide Tools. – Annals of the CIRP Vol. 38/1/1989.

The tool volume thermal-stressed state has been investigated.Due attention is paid to estimating the role of thermal and mechanical loads and adequately selecting the criteria of sizing-up the tool's strength. The data obtained as a. result of the performed investigations are used so as to explain the experimentally established characteristics of the tool's wear and fracturing in ths process of continuous and interrupted machining.

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Ostafiev V.A., Tymchik G.S. Laser Measuring Systems for Precision CNC Machine Tools

Sunday, 13 November 2011 20:29 administrator
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V.A. Ostafiev, G.S. Tymchik. Laser Measuring Systems for Precision CNC Machine Tools. – North-Holland. Computers in Industry 11 (1989) 229-234

The paper deals with developing of laser optoelectronic measuring instruments ЛИР-1, ЛИР-350 for the coordinates' determining of the cutting tool edge and subsequent compensating its dimensional wear directly on machine tools. The laser instruments' application permits noncontact measuring geometric dimensions of both the cutting tools and the workpieces to within 0.05 to 1 \im with reducing set-up time.

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Ostafiev V.A., Venuvinod Patri K. A New Electromagnetic Contact Sensing Technique For Enhancing Machining Accuracy

Sunday, 13 November 2011 20:19 administrator
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V.A. Ostafiev, Patri K. Venuvinod. A New Electromagnetic Contact Sensing Technique For Enhancing Machining Accuracy. – MED-Vol. 6-1, Manufacturing Science and Technology Volume 1 ASME 1997

This paper describes a new electromagnetic contact sensing technique called the "Fine Touch" method which enables the cutting tool itself i be used as a probe during on-machine measurement of parts. The simple sensor design of the probe (the cutting tool) has resulted in a low co system for workpiece set-up and inspection. Tests have shown that the sensor precision is of the order of 0.01 mm and, hence, could be used < coordinate measuring machines (CMM) as well. The sensor is effective irrespective of variations in cutting tool geometry, cutting insert coatnj insert geometry and size, cutting fluids, and workpiece material.

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Ostafjew V., Timtschik G. et al. Modern Quality Control In Manufacturing Processes With Universal Personal Computer Instruments And CCD Sensors

Sunday, 13 November 2011 20:23 administrator
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Wladimir Ostafjew, Grigorij Timtschik et al. Modern  Quality  Control  In  Manufacturing  Processes  With Universal Personal Computer Instruments And CCD Sensors. – International   Conference  on Manufacturing Systems  and Environment - Looking Towards the 21st Century-Tokyo, May 29 - June 1, 1990

Quality assurance in manufacturing processes over many years has been accomplished by manual acquisition and processing of measuring data in comparison with nominal values in technological working sheets.

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