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Tytuł:
Assessment of Free-Form Surfaces’ Reconstruction Accuracy
Autorzy:
Wójcik, A.
Niemczewska-Wójcik, M.
Sładek, J.
Powiązania:
https://bibliotekanauki.pl/articles/220773.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
reverse engineering
accuracy assessment
free-form surface
coordinate measuring machine
radius correction
Opis:
The paper presents the problem of assessing the accuracy of reconstructing free-form surfaces in the CMM/CAD/CAM/CNC systems. The system structure comprises a coordinate measuring machine (CMM) PMM 12106 equipped with a contact scanning probe, a 3-axis Arrow 500 Vertical Machining Center, QUINDOS software and Catia software. For the purpose of surface digitalization, a radius correction algorithm was developed. The surface reconstructing errors for the presented system were assessed and analysed with respect to offset points. The accuracy assessment exhibit error values in the reconstruction of a free-form surface in a range of ± 0.02 mm, which, as it is shown by the analysis, result from a systematic error.
Źródło:
Metrology and Measurement Systems; 2017, 24, 2; 303-312
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiscale assessment of additively manufactured free-form surfaces
Autorzy:
Gogolewski, Damian
Powiązania:
https://bibliotekanauki.pl/articles/2203371.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
free-form
wavelet transform
multiscale analysis
surface texture
additive manufacturing
Opis:
The article reviews the results of experimental tests assessing the impact of process parameters of additive manufacturing technologies on the geometric structure of free-form surfaces. The tests covered surfaces manufactured with the Selective Laser Melting additive technology, using titanium-powder-based material (Ti6Al4V) and Selective Laser Sintering from polyamide PA2200. The evaluation of the resulting surfaces was conducted employing modern multiscale analysis, i.e., wavelet transformation. Comparative studies using selected forms of the mother wavelet enabled determining the character of irregularities, size of morphological features and the indications of manufacturing process errors. The tests provide guidelines and allow to better understand the potential in manufacturing elements with complex, irregular shapes.
Źródło:
Metrology and Measurement Systems; 2023, 30, 1; 157--168
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parameters for CMM contact measurements of free-form surfaces
Autorzy:
Poniatowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/220454.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
coordinate measurements
free-form surface
geometric deviations
measurement parameters
Opis:
Obtaining discrete data is inseparably connected with losing information on surface properties. In contact measurements, the ball tip functions as a mechanical-geometrical filter. In coordinate measurements the coordinates of the measurement points of a discrete distribution on the measured surface are obtained. Surface geometric deviations are represented by a set of local deviations, i.e. deviations of measurement points from the nominal surface (the CAD model), determined in a direction normal to this surface. The results of measurements depend both on the ball tip diameter and the grid size of measurement points. This article presents findings on the influence of the ball tip diameter and the grid size on coordinate measurement results along with the experimental results of measurement of a free-form milled surface, in order to determine its local geometric deviations. One section of the surface under research was measured using different measurement parameters. The whole surface was also scanned with different parameters, observing the rule of selecting the tip diameter d and the sampling interval T in the ratio of 2:1.
Źródło:
Metrology and Measurement Systems; 2011, 18, 2; 199-207
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-rigid registration using hardware-accelerated free-form deformation
Autorzy:
Soza, G.
Bauer, M.
Hastreiter, P.
Nimsky, C.
Greiner, G.
Powiązania:
https://bibliotekanauki.pl/articles/332958.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
przesunięcie mózgu
rejestracja
sprzęt graficzny
brain shift
registration
free-form deformation
graphics hardware
Opis:
In this paper we introduce a new method for non-rigid voxel-based registration of medical images. There exist many applications where an alignment between two image datasets has to be established. Often a registration of a time-shifted medical image sequence with appearing deformation of soft tissue (e.g. pre- and intraoperative data) has to be conducted. Soft tissue deformations are usually highly non-linear. In our approach, for the handling of this phenomenon and for obtaining an optimal non-linear alignment of respective datasets we transform one of them using 3D Bézier functions, which provides some inherent smoothness as well as elasticity. In order to find the optimal transformation, many evaluations of this Bézier function are necessary. In order to make the method more efficient, graphics hardware is extensively used. We applied our non-rigid algorithm successfully to MR brain images in several clinical cases and showed its value.
Źródło:
Journal of Medical Informatics & Technologies; 2002, 3; MI181-188
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coordinate measurements of free-form surfaces in reverse engineering process
Autorzy:
Werner, A.
Powiązania:
https://bibliotekanauki.pl/articles/386544.pdf
Data publikacji:
2010
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
CAD
powłoka
pomiar
model 3D
surface
measurement
3D modeling
Opis:
This paper presents the issues of coordinate measurements of three-dimensional objects whose shape is defined with the use of parametric surface description methods applied in CAD systems. The paper also describes a mathematical as well as a geometrical presentation of surfaces used CAD systems, and discusses coordinate measurement techniques applied in measuring objects of this class. Further in the article, a practical implementation of the methodology of reconstruct- ing objects described with the use of free-form surface patches has been presented. The methodology includes subsequent object measurements and reconstructing the object’s geometric model, and concentrates on the possibly most accurate reconstruction of the shapes and dimensions of the researched object.
Źródło:
Acta Mechanica et Automatica; 2010, 4, 4; 102-105
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Osobiste doświadczenia z architekturą strukturalną: od poszukiwania formy do projektowania „free form”
Personal experiences in Structural Architecture: from form finding to free form design
Autorzy:
Majowiecki, M
Powiązania:
https://bibliotekanauki.pl/articles/293813.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
structural architecture
wide span structures
reliability
experimental analysis
monitoring
architektura strukturalna
konstrukcje o dużej rozpiętości
niezawodność
analiza eksperymentalna
monitorowanie
Opis:
Artykuł prezentuje doświadczenie autora i jego osobiste poglądy na wyzwania, które wynikają z nowych trendów w projektowaniu – Free Form Design (FFD). W oparciu o uzyskane doświadczenie można było zidentyfikować zagrożenia dla systemu konstrukcyjnego, jakie niesie ze sobą nieskrępowane tworzenie formy architektonicznej. Implikuje to potrzebę rozszerzenia zakresu i zmiany standardowego podejścia w analizie konstrukcyjnej.
The paper presents the author’s experience and his personal views on the challenges that arise from the new trend in design – Free Form Design (FFD). Based on the experience gained it was possible to identify the hazards that unfettered creation of architectural form poses for the structural system. This implies the need for extension of range and change of the standard approach in the structural analysis.
Źródło:
Architectus; 2014, 4(40); 79-92
1429-7507
2084-5227
Pojawia się w:
Architectus
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hand gesture recognition based on free-form contours and probabilistic inference
Autorzy:
Kasprzak, W.
Wilkowski, A.
Czapnik, K.
Powiązania:
https://bibliotekanauki.pl/articles/331308.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
śledzenie dłoni
analiza sekwencji obrazów
wnioskowanie stochastyczne
active contours
hand pose detection
hand tracking
image sequence analysis
stochastic inference
Opis:
A computer vision system is described that captures color image sequences, detects and recognizes static hand poses (i.e., 'letters') and interprets pose sequences in terms of gestures (i.e., 'words'). The hand object is detected with a double-active contour-based method. A tracking of the hand pose in a short sequence allows detecting 'modified poses', like diacritic letters in national alphabets. The static hand pose set corresponds to hand signs of a thumb alphabet. Finally, by tracking hand poses in a longer image sequence, the pose sequence is interpreted in terms of gestures. Dynamic Bayesian models and their inference methods (particle filter and Viterbi search) are applied at this stage, allowing a bi-driven control of the entire system.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 2; 437-448
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of coordinate measurement parameters on a free-form surface inspection results
Autorzy:
Poniatowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/386532.pdf
Data publikacji:
2010
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
pomiar
powierzchnia
badania
measurement
surface
researches
Opis:
Coordinate measurements are the source of digital data in the form of coordinates of the measurement points of a discrete distribution on the measured surface. The local geometric deviations of free-form surfaces are determined (at each point) as normal deviations of these points from the nominal surface (the CAD model). Obtaining discrete data is inseparably connected with losing information on the surface properties. In contact measurements, the ball tip functions as a mechanical-geometric filter. The results of coordinate measurements of geometric deviations depend not only on the grid size but also on the ball tip diameter. This article presents foundations of the influence of the ball tip diameter and the grid size on coordinate measurement results along with the experimental results of measurement of a free-form milled surface in order to determine its local geometric deviations.
Źródło:
Acta Mechanica et Automatica; 2010, 4, 4; 91-94
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method for enhanced accuracy in machining free-form surfaces on CNC milling machines
Autorzy:
Werner, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2105992.pdf
Data publikacji:
2022
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
free-form surface
milling
coordinate measurements
CAD model
data filtration
accuracy improvement
Opis:
The present article describes a method for enhanced accuracy in machining free-form surfaces produced on CNC milling machines. In this method, surface patch machining programs are generated based on their nominal CAD model. After the pretreatment, coordinate control measurements are carried out. The obtained results of the measurements contain information on the values and distribution of observed machining deviations. These data, after appropriate processing, are used to build a corrected CAD model of the surface produced. This model, made using reverse engineering techniques, compensates for the observed machining deviations. After regeneration of machining programs, the object processing and control measurements are repeated. As a result of the conducted procedure, the accuracy of the manufacture of the surface object is increased. This article also proposes the introduction of a simple procedure for the filtration of measurement data. Its purpose is to minimise the effect of random phenomena on the final machining error correction. The final part of the article presents the effects of the proposed method of increasing the accuracy of manufacturing on ‘raw’ and filtered measurement data. In both cases, a significant improvement in the accuracy of the machining process was achieved, with better final results obtained from the filtered measurement data. The method proposed in the article has been verified for three-axis machining with a ball-end cutter.
Źródło:
Acta Mechanica et Automatica; 2022, 16, 2; 103--110
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neural network based selection of optimal tool - path in free form surface machining
Autorzy:
Korosec, M.
Kopaz, J.
Powiązania:
https://bibliotekanauki.pl/articles/384505.pdf
Data publikacji:
2007
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
(NN) Neural Network
CAD/CAM system
CAPP
Intelligent CAM (ICAM)
milling strategy
Opis:
The purpose of the presented paper is to show how with the help of artificial Neural Network (NN) the prediction of milling tool-path strategies could be performed in order to determine which milling tool - path strategies or their sequences will yield the best results (i.e. the most appropriate ones) of free form surface machining, in accordance with a selected technological aim. Usually, the machining task could be completed successfully using different tool-path strategies or their sequences. They can all perform the machining task according to the demands but always only one of the all possible applied strategies is optimal in terms of the desired technological goal (surface quality in most cases). In the presented paper, the best possible surface quality of a machined surface was taken as the primary technological aim. Configuration of the applied Neural Network is presented and the whole procedure of determining the optimal tool-path sequence is shown through an example of a light switch mould. Verification of the machined surface quality, in relation to the average mean roughness Ra is also being performed and compared with the NN predicted results.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2007, 1, 4; 41-50
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Współczesna architektura drewniana w poszukiwaniu formy swobodnej
Contemporary wooden architecture in search of free form
Autorzy:
Golański, M.
Powiązania:
https://bibliotekanauki.pl/articles/970345.pdf
Data publikacji:
2017
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
architektura non-standard
architektura drewniana
free-form design
non-standard architecture
wooden architecture
Opis:
Kształtowanie nowoczesnej architektury zgodnej z założeniami zrównoważonego rozwoju wymaga zintegrowanego i synergicznego projektowania zarówno w przypadku noworealizowanych budynków jak i w modernizacji istniejących. Obiekty budowlane powinny wykazywać się nie tylko estetyką, funkcjonalnością i trwałością, lecz również w sposób nieszkodliwy oddziaływać na środowisko, być ekonomicznymi w zużyciu materiałów i energii oraz uwzględniać wszelkie ryzyka z punktu widzenia życia i zdrowia ludzkiego. Drewno, które należy do najstarszych materiałów budowlanych używanych przez człowieka obecne jest w środowisku zabudowanym od początku historii architektury. Modernizm charakteryzował się stopniowym wypieraniem drewna przez inne materiały budowlane: ceramikę, beton i stal. Fizyczne właściwości, łatwość kształtowania i nieskomplikowany proces produkcji w połączeniu z wyjątkowym potencjałem ekologicznym drewna sprawiają, że po okresie względnego regresu konstrukcje drewniane znów stosowane są na dużą skalę. Kreowanie form złożonych w architekturze współczesnej oraz rozwój cyfrowych narzędzi projektowania sprzęgniętych z komputerową technologią obróbki drewna sprawiają, że projektanci uzyskali nowe możliwości kształtowania obiektów architektonicznych. Architektura krzywoliniowa o swobodnej geometrii (free form design) odrzuca kartezjańską geometrię i konwencjonalny język brył euklidesowych. Niniejszy artykuł analizuje obiekty architektoniczne charakteryzujące się formami krzywoliniowymi oraz zastosowaniem drewna jako budowlanego materiału konstrukcyjnego.
Creation of modern architecture in accordance with the precepts of sustainable development requires an integrated and synergistic design for both new-built and refurbished buildings. The buildings should demonstrate not only the aesthetics, functionality and durability but also have harmless impact on the environment, be effective in material and energy consumption and take into account any risk factors from the point of view of human life and health. Wood, one of the oldest construction materials used by man is present in the built environment from the beginning of the history of architecture. Modernism was characterized by the gradual displacement of wood by other building materials: ceramics, concrete and steel. Physical properties, ease of shaping and effortless process of production, combined with the exceptional ecological potential of wood make wooden structures are widespread again after a period of relative contraction. Creating complex forms in the contemporary architecture and the development of digital design tools coupled with computer technology and CNC woodworking give designers new possibilities for shaping architectural forms. Curvilinear architecture (free form design) rejects Cartesian geometry and conventional language of Euclidean shapes. This article analyzes architectural structures characterized by curvilinear forms and the use of wood as a building material of construction.
Źródło:
Budownictwo i Architektura; 2017, 16, 4; 159-168
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determining the uncertainty of the object coordinate system position coordinate measurements of free-form surfaces
Autorzy:
Poniatowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/387272.pdf
Data publikacji:
2009
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
CAD
powłoka
badanie materiałów
surface inspection
Opis:
Coordinate measurements are a source of digital data in the form of coordinates of measurement points with a discrete distribution on the measured surface. Geometric deviations of free-form surfaces are determined at each point as nor- mal deviations of these points from the nominal surface (a CAD model). The calculations are preceded by fitting the measurement data to the CAD model. The relations between the object coordinate system and the coordinate system of the machine are described by the transformation parameters. This paper presents the idea of the process of data fitting with the use of the least square algorithm method as well as the way of determining the uncertainty on the assumption that transformation para- meters are subject to a multivariate normal probability distribution. The theoretical issues were verified by experiments carried out on a free-form surface obtained in the milling process and characterised by random geometric deviations.
Źródło:
Acta Mechanica et Automatica; 2009, 3, 4; 56-61
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free-form surface data registration and fusion. The case of roughness measurements of a convex surface
Autorzy:
Zawada-Tomkiewicz, Anna
Powiązania:
https://bibliotekanauki.pl/articles/221231.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stitching data
surface measurement
free-form surface
Opis:
Combining surface measurement data from individual measurements of surface fragments is an issue that has been recognized for flat surfaces. The connection takes place on the principle of making ‘overlap’ measurements according to a specific measurement strategy, and then the algorithm synthesizes the measurement data for the common part (data fusion). This paper presents a method of combining partial data into one larger set using image processing methods. The purpose of the analysis is to combine surface data of a more complex shape in terms of surface roughness and waviness. A successful attempt was made to combine surface measurement data located on a cylindrical surface - convex surface. A rotated table was designed and used for surface data acquisition. The datasets were acquired with the use of CCI 6000 (366μm - 366μm) with the assumed overlapping of at least 20%. The measurement datasets were first pre-processed: filling in non-measured points, levelling and form removing were applied. For such processed datasets, the common part was identified (data registration) and then the data fusion was performed. An example of stitching the surface datasets shows usefulness of the presented methodology.
Źródło:
Metrology and Measurement Systems; 2019, 26, 2; 323-333
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation tests of the method for determining a CAD model of free-form surface deterministic deviations
Autorzy:
Poniatowska, M.
Werner, A.
Powiązania:
https://bibliotekanauki.pl/articles/221700.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
coordinate measurement
geometric deviation
free-form surface
regression analysis
CAD model
Opis:
Geometric deviations of free-form surfaces are attributed to many phenomena that occur during machining, both systematic (deterministic) and random in character. Measurements of free-form surfaces are performed with the use of numerically controlled CMMs on the basis of a CAD model, which results in obtaining coordinates of discrete measurement points. The spatial coordinates assigned at each measurement point include both a deterministic component and a random component at different proportions. The deterministic component of deviations is in fact the systematic component of processing errors, which is repetitive in nature. A CAD representation of deterministic geometric deviations might constitute the basis for completing a number of tasks connected with measurement and processing of free-form surfaces. The paper presents the results of testing a methodology of determining CAD models by estimating deterministic geometric deviations. The research was performed on simulated deviations superimposed on the CAD model of a nominal surface. Regression analysis, an iterative procedure, spatial statistics methods, and NURBS modelling were used for establishing the model.
Źródło:
Metrology and Measurement Systems; 2012, 19, 1; 151-158
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measuring the accuracy of producing free-form surfaces with the use of the coordinate measuring method
Autorzy:
Werner, A.
Powiązania:
https://bibliotekanauki.pl/articles/386542.pdf
Data publikacji:
2010
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
produkcja
CAD
CNC
powłoka
model 3D
production
surface
3D modeling
Opis:
The present paper presents a method of determining errors in processing complex-shape surfaces produced with the use of a CNC machine tool. In order to achieve this, the whole process of making a three-dimensional object was performed, from creating a CAD model to generating a processing programme for a CNC machine tool and producing the actual object. The obtained surface was measured with a Brown & Sharpe Mistral coordinate measuring machine with the use of a Renishaw TP200 measuring probe.
Źródło:
Acta Mechanica et Automatica; 2010, 4, 4; 99-101
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 47

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