Wyniki wyszukiwania - BazTech

1

Evolutionary and Sparse Regression Approach for Data-Driven Modelling of an Overhead Crane Dynamics

Kusznir Tom, Smoczek Jarosław, Karwat Bolesław

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 4

282--295

EN

Identification of an accurate and simple model of a complex underactuated crane dynamics for varying operational conditions is a crucial step towards designing and implementation of real-time monitoring and control systems to enhance crane safety and operational efficiency. This paper considers a non-parametric data-driven identification of an overhead crane dynamics using symbolic regression techniques to find compromise between model complexity and predicted output accuracy. A grammar-guided genetic programming (G3P) combined with l0 sparse regression is applied with two different variants of grammar to automatically construct a nonlinear autoregressive exogenous (NARX) model of different forms, termed extended and polynomial models. The proposed method is compared with a linear parameter-varying ARX (LPV-ARX) model. Identification is performed on experimental data obtained from a laboratory-scale overhead crane. The identified models are compared in terms of prediction accuracy, model’s complexity measured using number of model terms, and execution time. The regularized G3P method outperformed the LPV-ARX model in terms of model predictive output accuracy. The G3P with the extended grammar resulted in more accurate crane velocity prediction models than the models with the polynomial grammar. The payload sway prediction model with the polynomial grammar was less complex in all measured metrics while there was no statistical significance in the accuracy when compared to the models with extended grammar.

2

The Use of 3D Imaging in Surface Flatness Control Operations

Sioma Andrzej, Karwat Bolesław

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 6

335--344

EN

The paper presents a surface flatness control system designed for installation on a production line. Such a system allows the control of all blanks leaving the production line in terms of measuring flatness made in the conditions prevailing on the production line. The article discusses 3D imaging methods enabling the construction of a surface image. An analysis of imaging parameters for each method is presented. For the selected imaging method, an analysis of the imaging resolution is presented. An example of flatness measurement for a selected element after a welding operation is shown. The flatness measurement algorithm is discussed, and the results of measurements are presented. The results of measurements for selected two product groups are presented.

3

Numerical simulations of the exploitation parameters of the rotary feeder

Karwat Bolesław, Rubacha Piotr, Stańczyk Emil

Management Systems in Production Engineering

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2022

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nr 4 (30)

Bibliogr. 33 poz., rys., tab.

EN

The article presents the problems of determining the mass efficiency of a rotary feeder depending on the selection of design parameters of the device, such as outer diameter, number of blades and rotational speed of the rotor. The hitherto theoretical methods of calculating the feeder efficiency were presented, as well as a new method of determining the device operation parameters was proposed. For this purpose, the numerical Discrete Element Method was used, which allowed simulating the transport of limestone powder in a cell feeder with various design variants. The results of the tests showed that the above design parameters affect the instantaneous efficiency of the feeder and thus impact the distribution of the dosed material during the operation of the device. Depending on the design solution, the simulation results gave information on the fill factor of the feeders. The study showed a significant potential of DEM simulation in the design of circular feeders intended for dosing bulk materials.

4

Optimization of a screw conveyor's exploitation parameters

Karwat Bolesław, Rubacha Piotr, Stańczyk Emil

Eksploatacja i Niezawodność

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2021

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Vol. 23, no. 2

285--293

EN

The paper describes the problem of designing screw conveyors in terms of determining their exploitation characteristics. Based on the actual values of mass efficiency and power demand obtained in a laboratory experiment, the theoretical design methods and the numerical discrete element method model results were verified. The obtained results have shown that the currently used theoretical methods underestimate the mass efficiency and power demand compared to experiments when typical values of filling rate coefficient and progress resistance coefficient are used. It was also shown that the results of DEM simulations are in good agreement with the experiments in terms of mass efficiency and power demand. Based on the exploitation characteristics determined in DEM simulations for different constructions of the screw and different rotational speeds, multi-objective optimization of the exploitation parameters of the screw was performed in order to minimize the power demand of a screw conveyor and simultaneously maximize its mass efficiency. The optimization results showed that it is possible to find such construction and the rotational speed that will maximize the mass efficiency of the conveyor and keep the power demand low, reducing the exploitation costs of the device.

5

Simulational and experimental determination of the exploitation parameters of a screw conveyor

Karwat Bolesław, Rubacha Piotr, Stańczyk Emil

Eksploatacja i Niezawodność

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2020

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Vol. 22, no. 4

741--747

EN

The paper discusses the designing process of screw conveyors, with regard to the determination of the exploitation parameters of such devices with the use of the Discrete Element Method (DEM). The influence of the chosen model input parameters on the results of the simulations was examined. The key parameters which determine the exploitation characteristics of a screw conveyor were identified as follows: the size of a DEM particle, coefficients of internal and external friction. Experimental measurements of the laboratory screw conveyor provided the actual exploitation characteristics of a device used for the transportation of a limestone powder. The comparison of the results of the simulations and experiments gave satisfactory results. For this reason, DEM simulations were identified as an effective tool for determining and optimization of the construction and exploitation parameters of the screw conveyors.

PL

W artykule przedstawiono problematykę projektowania przenośników ślimakowych w aspekcie wyznaczenia parametrów eksploatacyjnych urządzenia z użyciem Metody Elementów Dyskretnych (DEM). Badania symulacyjne wpływu wybranych parametrów modelu materiałowego DEM pozwoliły określić kluczowe czynniki, takie jak: rozmiar cząstki DEM, wartość współczynnika tarcia wewnętrznego oraz zewnętrznego, czynniki które determinują wyniki charakterystyk pracy przenośnika ślimakowego. Badania eksperymentalne przeprowadzone przy użyciu laboratoryjnego przenośnika ślimakowego dostarczyły rzeczywiste charakterystyki eksploatacyjne urządzenia transportującego mączkę wapienną. W metodzie DEM zamodelowano stanowisko badawcze celem wyznaczenia analogicznych charakterystyk pracy. Porównanie wyników symulacji oraz badań eksperymentalnych określających parametry eksploatacyjne przenośnika dało satysfakcjonujące rezultaty. Dlatego symulacje DEM mogą być skutecznie wykorzystywane do wyznaczania i optymalizacji parametrów konstrukcyjnych i eksploatacyjnych przenośników ślimakowych.

6

Możliwości recyklingu popiołów lotnych powstających ze spalania biomasy w zakładach przetwórstwa drewna

Karwat Bolesław, Machnik Ryszard, Nogaj Magdalena, Niedźwiedzki Jerzy

Przemysł Chemiczny

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2019

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T. 98, nr 9

1411--1413

PL

Pyły ze spalania odpadów drzewnych mają właściwości fizykochemiczne oraz elektryczne kwalifikujące je do grupy zanieczyszczeń pyłowych łatwych do separacji metodami elektrostatycznymi. Ze względu na małą zawartość części palnych oraz niską aktywność promieniotwórczą, pyły te mogą być z powodzeniem użyte do produkcji materiałów budowlanych stosowanych w budynkach mieszkalnych. Ze względu na skład chemiczny tego typu pyły mogą stanowić komponent nawozów.

EN

Three fly ashes from wood biomass combustion were studied for d., unburned C content, particle size distribution, chem. compn. (as oxides), concn. of natural radionuclides (40K, 226Ra and 228Th) and heavy metals as well as changes in temp. relationship of resistivity. No heavy metals (Hg, Pb, Cd, Cr, Ni and Bi) were found in the fly ashes. The compn. of ashes and low concn. of radionuclides indicated the possibility of using them in construction and agriculture.

7

Calibration of bulk material model in Discrete Element Method on example of perlite D18-DN

Karwat Bolesław, Machnik Ryszard, Niedźwiedzki Jerzy, Nogaj Magdalena, Rubacha Piotr, Stańczyk Emil

Eksploatacja i Niezawodność

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2019

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Vol. 21, no. 2

351--357

EN

Analytical methods for calculations of the transport machinery are often insufficient especially when untypical granular materials are considered. Discrete Element Method (DEM) is a very useful numerical tool supporting designing and optimization of the transport equipment. However, to obtain reliable DEM simulation results an accurate set of input parameters values is needed. The most common calibration approach is to make use of a procedure where laboratory tests are performed and then the same experiments are numerically replicated in DEM. The article presents calibration of the DEM input parameters on the example of perlite D18-DN Based on the performed calibration, the model of perlite transport in a screw conveyor has been shown.

PL

Analityczne metody obliczeniowe parametrów konstrukcyjnych maszyn i urządzeń transportowych są często niewystarczające, zawłaszcza w przypadku transportu nietypowych materiałów sypkich. Pomocnym narzędziem numerycznym wspierającym proces projektowania i optymalizacji urządzeń do transportu materiałów sypkich jest Metoda Elementów Dyskretnych (DEM). Uzyskanie wiarygodnych wyników symulacji wymaga kalibracji parametrów wejściowych modelowanego materiału wykorzystując wyniki badań laboratoryjnych właściwości fizykochemicznych rzeczywistych materiałów. W artykule przedstawiono metodologię kalibracji modelu DEM na przykładzie perlitu D18-DN. W oparciu o przeprowadzoną kalibrację zaprezentowano możliwości zastosowania metody DEM do symulowania transportu materiału przenośnikiem ślimakowym.