Acta Mechanica Slovaca, 2009 (vol. 13), issue 3

Fractal Company

Hans Jürgen Warnecke

Acta Mechanica Slovaca 2009, 13(3):6-13 | DOI: 10.2478/v10147-010-0041-1  

More and more branches are confronted with fast changes of products, technologies and markets and it is hard to manage its position with the traditional methods of reorganization, re-engineering, computer integration or by new more flexible technology. The only chance is to create such adaptable organization which will react adequately to these changes by itself. Living organisms that are strongly adaptable to changed conditions because they are designed with self-organized elements; similarly to them the fractal organization uses suchlike principle. Individual organizational sections are autonomous, they organize and optimize themselves and so create...

An Approach in Development of System for Production Scheduling

Slavica Cvetković

Acta Mechanica Slovaca 2009, 13(3):14-21 | DOI: 10.2478/v10147-010-0042-0  

This paper presents a system for production scheduling which is a part of production planning system. Production scheduling according to delivery time is specially considered and launch plans for parts are determined according to structural components. Using system of different applications and report types, developed program gives support for business decision making which considers production planning and scheduling.

An n-Link Inverted Pendulum Modeling

Alexander Gmiterko, Martin Grossman

Acta Mechanica Slovaca 2009, 13(3):22-29 | DOI: 10.2478/v10147-010-0043-z  

In this article is the automatized procedure for deriving of n-link inverted pendulum motion equations presented. Example of 2 link inverted pendulum is included. The LQR algorithm using Maple input equations is proposed. Also the comparison between SimMechanics and Simulink is included.

Design of the Welding Fixture for the Robotic Stations for Spot Welding Based on the Modular Concept

Mikuláš Hajduk, Ján Semjon, Marek Vagaš

Acta Mechanica Slovaca 2009, 13(3):30-37 | DOI: 10.2478/v10147-010-0044-y  

The article describes the methodological approach to design of welding fixtures for robotic cells based on principles of modularity. In further states the basic preparation components, their functions and possible board types in terms of shape and dimensional characteristics. The proposed methodology was tested for robotic training workstation with robot KUKA for spot welding of car bodies.

Optimal Tuning Method of Ships System by Means of Pneumatic Tuner of Torsional Oscillations

Jaroslav Homišin, Peter Kaššay

Acta Mechanica Slovaca 2009, 13(3):38-47 | DOI: 10.2478/v10147-010-0045-x  

Drives of mechanical systems consist of driving machines and gearing mechanisms connected together by means of shafts and couplings. With regard to the dynamics it is possible to say that every driving mechanism is a system, which is able to oscillate. Especially piston machines are able to create dangerous and harmful torsional oscillations, vibrations, as well as noisiness.Important task of designer is reduction of torsional oscillations in mechanical system. Presently this problem is solved predominately with a suitable adjustment of dynamic properties of flexible shaft couplings with regard to the dynamic properties of given system. It means...

Short and Long Term Sampling of Micro and Macro Displacements in Robotics

Milan Kvasnica

Acta Mechanica Slovaca 2009, 13(3):48-53 | DOI: 10.2478/v10147-010-0046-9  

The paper deals with the analysis of the accuracy of the short and long term measurements in the six degrees-of-freedom (DoF) measurement system used for the sampling of axial shiftings and angular displacements, structural dynamic properties of robotic systems, engineering constructions and for the control operation in space. The analysis of the accuracy is based on algorithms for direct and inverse transformation for the computation of three axial shiftings and three angular displacements values in order to determine the relative location and orientation of a floating 2-D coordinate system against fixed 3-D coordinate system of laser rays.

Influence of Higher Alcohols on the Combustion Pressure of Diesel Engine Operated with Rape Seed Oil

Tamás Laza, Ákos Bereczky

Acta Mechanica Slovaca 2009, 13(3):54-61 | DOI: 10.2478/v10147-010-0047-8  

To replace diesel fuel in IC engines, one of the most used alternatives is rape seed oil. In this research rape seed oil has been blended with higher alcohols as the 1-butanol and 2-propanol in 10 or 20 vol% to reduce viscosity. We present our results investigating the effect of these blends on the combustion process and on the emission. We describe the measurement system and the calculation methods applied for evaluation. Results show that both blends have significant effect on the pollutant emission, but the concrete effect may differ from blend to blend. The smoke emission significantly decreases, but there is an increment in the CO and THC emissions....

Turbojet Engines - Progressive Methods of Modeling

Ladislav Madarász, Rudolf Andoga, Ladislav Főző

Acta Mechanica Slovaca 2009, 13(3):62-73 | DOI: 10.2478/v10147-010-0048-7  

Small turbojet engines represent a special class of turbine driven engines. They are suitable for scientific purposes and research of certain thermodynamic processes ongoing in turbojet engines. Moreover such engines can be used for research in the area of alternative fuels and new methods of digital control and measurement. Our research, which is also presented in this article, is headed toward these aims. We evaluate and propose a system of digital measurement of a particular small turbojet engine - MPM 20. Such engine can be considered as highly non-linear large scale system. According to obtained data and experiments we propose different approaches...

Application of Environment Management Systems in Environmental Security and Risk Prevention

Milan Majerník, Jana Chovancová

Acta Mechanica Slovaca 2009, 13(3):74-83 | DOI: 10.2478/v10147-010-0049-6  

The development of industrial production, implementation of new technologies, using of growing number of dangerous substances brings remarkable risks tightly related to health and environmental threads. In the submitted article authors present an approach of the environmental risk prevention and present the Environmental management system as effective tool of the environmental risk prevention. The identification of the environmental aspects, impacts and risks and their characteristics and assessment in the specific register is the first and key step of the environmental risk prevention. Positive experience of the environmental management system applications...

Properties and Performance of Hard Coatings on Tool Steels under Cyclic Indentation

Alina Sivitski, Andre Gregor, Mart Saarna, Priit Kulu, Fjodor Sergejev

Acta Mechanica Slovaca 2009, 13(3):84-95 | DOI: 10.2478/v10147-010-0050-0  

In this paper cracking resistance and fatigue properties of five hard coatings - TiN, TiCN, TiAlN, AlTiN and nanocomposite nACo® (nc-AlTiN/a-Si3N4) on tool steels - Weartec™ and Vanadis 6 are evaluated by means of the cyclic Vickers indentation method. The analytical part covers an evaluation of damage evolution of the coated system versus the number of cycles. The effect of mechanical response - Young's module/Hardness ratio (E/H ratio) on the crack propagation is described in the form of a diagram with various curves, each one associated with a certain number of indentation cycles. The comparative adhesion testing was conducted with the...