Mechanics
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ISSN 1734-8927
e-ISSN: 2300-7060
Issue Date
2006
Volume
Vol. 25
Number
No. 4
Description
Journal Volume
Mechanics
Vol. 25 (2006)
Projects
Pages
Articles
Automation of selected electrodynamic plastic metalworking operations
(Wydawnictwa AGH, 2006) Bednarczyk, Józef
The article presents examples ofautomated seats designed for electrodynamic metalworking, which have been built at the Department of Process Control - the University of Science and Technology (AGH-USC) in Cracow. Electrodynamic technology, which is intensely developed abroad, is one of the methods involving high-power plastic metal forming. It maintains characteristics of other surge-type methods, e.g. explosive or electro-hydrodynamic, regarding working potential, and at the same time it may be fully automated, unlike these methods. Presented materiał contains descriptions concerning electrodynamic execution of three industrial operations: incandescent lamp unit assembly, convexity forming in teapot bowl and metal sheet forming, all fully automated with pneumatic dri-ves and programmable logie controllers.
On statistical parameters characterizing vibrations of oscillators without damping and forced by stochastic impulses
(Wydawnictwa AGH, 2006) Jabłoński, Marian; Ozga, Agnieszka
Our theoretical study aims at finding the statistical parameters characterizing the vibrations of an oscillator wi-thout damping and forced by stochastic impulses magnitude of the different distribution. We will derive the dependence of these parameters on rigidity and mass of the oscillator and on the stochastic distribution of the impulse magnitude. We will also carry out a numerical simulation verifying the derived mathematical model and interpret the differences between the results obtained in simulation and the mathematical calculations. This study is the first stage of research aimed at designing and calibrating a probe that will facilitate measuring of parameters determining the ąuality of a technological process.
Advanced control algorithm for stabilization rotational speed in hydrostatic transmission
(Wydawnictwa AGH, 2006) Nawrocka, Agata; Kwaśniewski, Janusz
This study focuses on the adaptive controller to control hydrostatic transmission. A hydrostatic transmission with a variable efficiency pump and a radial engine with constant working absorptivity was chosen. Pump efficiency was controlled using an electrohydraulic control system, comprising a hydraulic cylinder coupled with a pump rotor via a piston rod and a hydraulic servo-valve. As the object is nonlinear and time variant its control is very difjicult. For that reason the adaptive control strategy was chosen and a follow-up control algorithm was designed. This control strategy enables the fine tuning of the fuzzy logie controller's parameters. It can be done online, in each cycle time. Besides, this algorithm is implemented on a PLC controller. This paper outlines the structure of the controller and provides the results of laboratory tests.
Stress analysis in helical springs with closed end coils machined from cylindrical sleeves
(Wydawnictwa AGH, 2006) Salawiński, Józef; Michalczyk, Krzysztof
The review of stress calculation methods in helical springs with rectangular cross-section wire is introduced in this paper. It is demonstrated that methods described in literaturę have various accuracy. Also, the modern construction of helical spring machined from tubular blanks is presented. It is indicated, using Finited Elements Me-thod, that existing for classical springs with opened ends stress calculating methods, are not suitable for springs with capped ends, because the stresses calculated from them are much smaller than the real ones.
Estimation of the wear in positive-displacement pumps by the time series method
(Wydawnictwa AGH, 2006) Stojek, Jerzy
The article discusses the possibility to assess the wear characteristics in multi-piston positive-displacement pumps operating at constant delivery rate, basing on an analysis of the measured outlet pressure variations. Parameter estimates of the selected parametric models of pressure variations were determined. Comparing the values of parameters, the wear and tear characteristics were determined in the examined pumps.