Stefan Medvecky

University of Žilina · Center for Applied Research (CAV)

Driver fatigue can be manifested by various highly dangerous direct and indirect symptoms, for example, inattention or lack of concentration. The aim of the study was to compare the behavior of young drivers, older drivers and professional drivers, particularly in situations where they feel fatigued. In the online questionnaire, drivers answered va...

This article describes the design of a smart steering wheel intended for use in unobtrusive health and drowsiness monitoring. The aging population, cardiovascular disease, personalized medicine, and driver fatigue were significant motivations for developing a monitoring platform in cars because people spent much time in cars. The purpose was to cre...

The article deals with an optimization procedure of roller elements geometry with regard to durability of spherical roller bearings. The aim of the article is to examine the impact of change of the roller elements inner geometry on durability and reliability of spherical roller bearings; the contact strain along a spherical roller by means of the F...

This conference proceeding presents contributions to the 59th International Conference of Machine Design (ICMD 2018), organized by the University of Žilina, Faculty of Mechanical Engineering, Department of Design and Mechanical Elements. Discussing innovative solutions applied in engineering, the latest research and developments, and guidance on im...

Summary. This article presents the correct adjustment of the mower’s blade movement relative to the forward movement of the mower. Everywhere around us are gardens, parks and meadow, which gives us reason to solve issues with mowing. The first part of this article shows agricultural machines, which are used today and the principle of correct cut of...

Currently, the process of manufacturing the goods and then distributing them to the customer is constantly optimized, accelerated and automated. For these aspects, goods handling and automated storage play a key role. This article focuses on designing and optimizing the mechanisms that are parts of vending machines. Both static and dynamic models o...

This article deals with the kinematic analysis of trapezoidal suspension. Specifically, it focuses on the behaviour of the chassis when obstacle crossing was monitored. Our team is developing an autonomous mountain vehicle that will be equipped with different working adapters such as a cutter bar and a picker. The device was designed for work on sl...

The aim of the article is to show the principle of adjusting the blades movement relative to the forward mower movement. For this Analysis was used software MSC.Adams, which was connected to MATLAB for better data post processing. Finally, the blade's paths were mapped to figure, where we found the optimal speed of blades to mower's movement (with...

The subject of the article is the conceptual design of the automated drug dispenser and the characterization of its basic parts. The dispenser consists of a dispensing and delivery mechanism. The effort of pharmacies to maintain a high quality of services, the ability to keep up with the competition, are some of the main reasons why the pharmacies...

This article describes a method to identify partial sources of noise and their respective effects on the overall noise level of a clothes dryer. The focus is on the major sources of noise and options to control their noise levels so that the resulting declaration program produces as effective as possible acoustic improvement, while maintaining the...

This paper presents the layout of the about-ground weighbridge. There is requirement on the implementation of this device in order to re-measure the weight of the vehicles used for transportation of the steel waste collected to the collecting yard. The weighbridge is used wherever the vehicles must be weighed in order to not exceed the maximum perm...

Verified numerical simulation of heat transfer through the structure is an effective tool that allows to shorten development time and reduce development costs. The thesis describes numerical simulation of heat transfer in a heating unit structure for sapphire single-crystal growth. Heat transfer through radiation and conduction was simulated using...

The application of Theory of Inventive Problem Solving (TRIZ) into sapphire single crystal growth process provided thorough analysis of a problem as well as introduced two conceptually new solutions. The innovation of the Bagdasarov-Horizontally Directed Crystallization (HDC) by resolving the pollution of the observation window improves the control...

In the field of engineering relatively new designs and manufacturing processes are constantly emerging. These changes are often seen in designing and manufacturing of prototypes or in single part production. We decided to analyse an aircraft propeller prototype using modern technologies. Existing aircraft blade design was converted to digital model...

The objective of this paper is to describe the procedure of correct determination of the optimum preload of tapered roller bearings in terms of their fatigue life, using the procedure laid down in ISO 281, and by analysis of contact stress state (analytically and by the FEM) with application of the Lundberg-Palmgren theory. The procedures will be a...

The study is concerned with the basic conditions to create a thermographic atlas of the human body. The main goal of research had been measurement and comparison in temperature distribution of healthy human bodies which were obtained by infrared thermography for one year. It was used Infrared Imager with detector type 320x240 Focal Plane Array. For...

This work proposes a modified procedure, based on analytical integrations, to analyse poroelastic models discretized by time-domain Meshless Local Petrov-Galerkin formulations. In this context, Taylor series expansions of the incognita fields are considered, and the related integrals of the meshless formulations are solved analytically, rendering a...

This paper deals with accurate geometric models of rolling bearing components in the CAD system. This model is then employed to create a static structural analysis used to determine the size of stress between the components of a rolling bearing. Following the stress analysis, we specify the maximum load of a rolling bearing with regards to durabili...

The aim of this paper is to detail the creation of a roller bearing model in the Adams program suite for subsequent dynamic analysis and to obtain information about different parts of the bearing during the simulation. The bearing model was made so as to closely resemble its reallife counterpart, which allows us to estimate load conditions, dynamic...

This article details the design of an apparatus used in service life testing of large-scale rolling bearings on Faculty of Mechanical Engineering at University of Žilina. It describes individual steps in the design process, used parts and methods employed throughout the design process. One chapter is devoted to measurement techniques used in servic...

The paper presents the results of research & development of the Digital Factory solutions in industry. The implementation of this technology in industry is described and discussed. The results of research and development cover design of assembly system, its processes, simulations model, ergonomic analysis etc. In the paper are presented the solutio...

This article discusses steps towards the design, construction and production of a device used for lifetime assessment of large-scale bearings. The machine is reviewed as a mechatronic entity, comprised of three parts - mechanical, electro technical and hydraulic. The mechanical part was designed with the help of modern CAD/CAE/PDM design systems al...

This paper focuses on the Digital Factory technologies, the areas of their application, as well as its benefits for industry. The paper presents the Digital Factory concept built in the framework of co-operation of the University of Zilina and the Central European Institute of Technology (CEIT).

Paper industry deals with procedures for conceptual and final design of a machine Intended for unwinding paper that remains on reels during a certain phase of paper producing. Design procedure of the machine is a subject of this paper. The machine was designed as a mechatronic unit consisting of a mechanical part, an electric part and a pneumatic p...

1. Abstract The goal of the paper is to present the application of the new discrete optimization algorithm to structural mass minimizing,subjected