Thesis deals with the analysis of the sliding contact in the ring mill. It focuses on the assessment of the effect of the current load on the sliding contact, the assessment of the signal transmission quality from the static to the rotara part of the ring contact slide contact.

This thesis deals with computational modeling of curve squeal noise phenomena which occurs during cornering tight curves by trams. Lateral creep between rail and wheel and slip-stick phenomena leads to self-excited vibrations of the wheel which, therefore, emits unpleasant high-pitched noise. Two FEM models in frequency domain are carried out. First model is based on prestressed modal analysis. Due to unsymmetric stiffness matrix, unstable eigenvalues can occur. It is assumed that self-excited vibrations occurs on frequencies corresponding to that eigenvalues. Second model uses harmonic response analysis. It examines vibrations of the wheel excited by lateral creep force acting in contact region. This force is obtained externally by simple time-domain model. Results from harmonic response are used consequently for noise radiation computation.

This diploma thesis “Analysis of powertrain impact on pull power capacity of a tractor” is focused on evaluation of measured data gained from performance testing of tractors Claas Arion 640 for two different types of transmission. There are also discussed the measuring methods and there is detailed described the function of measured transmissions.

The master’s thesis deals with ways of controlling starting clutches of cars, especially of DQ200 gearbox, which contains dry disc clutches. The introduction describes basic principles of torque transfer and amount of clutch force. Then the description of construction of starting clutches and ways of controlling clutch types mentioned beforehand is given. In the next part of the thesis, wide spectrum of control methods is measured, from which a certain part is selected. This is followed by driving tests and based on driving data, one method of the clutch control is chosen. Then those control methods from narrow selection are tested for acoustic impact in the cabin of the car. In the end the best way of clutch control is selected. The selection based on driving data and acoustic measurement.

Byl studován kontakt mezi koulí a deskou pod tangenciálním zatížením ve vodě. Jako zdroj střižných kmitů byl použit akustický rezonátor (křemíkové mikrováhy – QCM). Kontakt koule s povrchem resonátoru indukuje změnu resonanční frekvence a šířky pásma. Byla měřena změna frekvence f a změna šířky pásma v závislosti na amplitudě oscilací. S rostoucí amplitudou docházelo k poklesu f a růstem , což je chování typické pro parciální skluz. Díky aplikaci Cattaneo-Mindlinova modelu byl vypočítán kontaktní poloměr a třecí koeficient. Kontaktní poloměr při nízké amplitudě stoupal při zvětšujícím se normálovým zatížením. Tato závislost se dobře shodovala s JKR modelem. Třecí koeficient se nacházel v odpovídajícím rozsahu. Při zvyšování externí normálové síly, docházelo k nepatrnému snižování hodnoty třecího koeficientu. Toto chování je vysvětleno příspěvkem adhezivních sil k totální normálové síle. Výpočtem byly získány dva typy třecích koeficientů, první ze změny frekvence f a druhý ze změny šířky pásma . Tyto dvě hodnoty se spolu shodovaly z ± 20 % pro měření prováděná ve vodě, zatímco pro dvě měření prováděných na hydrofilním povrchu ve vzduchu se lišila. Tento nesoulad poukazuje na nedostatek Cattaneo Mindlinovy teorie a mohl by být vysvětlen přítomností kapilárních sil.

This thesis deals with the asynchronous engines, describes their structure, principles, properties, use, and briefly describes the design of three-phase asynchronous motor. The first section describes the most common three-phase induction motor, the emergence of the rotating magnetic field and the basic relationships. The second part deals with asynchronous motors for specific applications, their design and features. The next section is an analysis engine borrowed from the electric company ATAS Náchod, and The last section lists ways to improve the basic parameters of induction motors designed and optimized engine.

This thesis is focused on a firmware for robotic vehicle based on the ARM Cortex-M3 architecture that is running a real-time operating system (RTOS). Theoretical part describes available solutions of embedded RTOS and concrete HW implementation of the robotic vehicle. There is also comparison of the three selected RTOS with their measurements. Result of this thesis is base firmware compounded by a program modules that controls HW parts. There is also a sample PC and firmware application that extends base firmware. This sample application is able to communicate with robotic vehicle, control wheel motion and measure process data.

This master’s thesis focuses on the minimisation of losses by calculation of optimum slip frequency of induction motor. The next point of this master‘s thesis is supersaturation. Supersaturation must be solved for the size of losses, because of the effect that is cause of the losses, when current increases with saturation. However current is not increase proportionally with increasing saturation, but increases several times more. This problem is included in the calculation of the slip frequency. Optimum of slip frequency is solve for modified gamma model of induction machine. In the main point of this thesis is outlined the process, how the optimum can be found. With same process were already were found the equations, but they were too extensit. In the end is solved the optimum of slip frequency be minimum of the flux density.

Multiple step tests under cyclic strain control have been performed using cylindrical specimens of cast polycrystalline Inconel 738LC superalloy at 23, 700, 500, 800 and 900 °C in laboratory atmosphere to obtain cyclic stress-strain curves. During cyclic straining of specimen were obtained cyclic hardening-softening curves. Their progress changed with temperature and strain amplitude. Evaluated cyclic stress-strain curves are shifted to lower stresses with increasing temperature. Surface relief was observed in fatigued specimens under SEM and metalography under optic microscopy. Slip markings were studied on specimen surface fatigued at 700 °C .Stress-strain response is compared and discussed in relation to the surface observations - persistent slip markings.

Work tackles the general design systems of automatic control of engine power and braking effects so that avoid any unnecessary dangerous situations and to improve the driving characteristics and suppression causes of accident due to bad decisions of driver. Is required to propose a general system based on the draft sensors and control circuits, their relationships, design control processor, which will be without the knowledge of the driver intervene in driving motorcycle.