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Cutting force calculations for milling
Prášil, Vojtěch ; Polzer, Aleš (referee) ; Klíč, Daniel (advisor)
Milling is nowadays one of the most important machining operations, and therefore it is necessary to deal with the processes involved. The main objective of this work is to compare different methods of calculating cutting forces with the results obtained by direct measurement. The experiment was carried out by direct measurement on a piezoelectric dynamometer where the workpiece was clamped while milling on a CNC milling machine. The first technique designed to determine the cutting forces analytically was their calculation on machining calculators. Two mobile application calculators and one online web application calculator were selected for this purpose. The second technique was to calculate the cutting forces using formulas from the standards. The cutting conditions corresponding to the dynamometer experiment were inserted into all calculations. The comparison shows that for face milling, the calculations from the standards and from the Hoffmann MC calculator achieved acceptable values compared to the measured ones. However, the results calculated for milling the sides differ significantly from those measured.
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Testbend for dynamic loading of electric drives
Valášek, Ondřej ; Pruša, Radomír (referee) ; Huzlík, Rostislav (advisor)
The thesis deals with the development and implementation of a PLC program in a workplace for dynamic loading of electric drives. Initially, an analysis of the dynamics of electric drives is performed, including the principle of operation of permanent magnet synchronous motors. The effects of control and design parameters of the electric motors on the resulting dynamic parameters of the system are then described. The practical part of the work first deals with the recovery of the workstation for operation in manual mode in order to determine the important parameters for the operation of the inverter in the dynamic brake mode. Based on the obtained variable parameters, a control program is developed and soon implemented in the PLC. The designed program is then verified by loading the DC motor in both speed and torque loop with constant and variable parameter change time. The data from the validation tests are evaluated and displayed in graphs that describe the measurement outputs. Finally, recommendations for workplace optimization are given. A manual for operating the workstation and controlling it from the user interface in Connect is included.
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The influence of Red Bull energy drink on speed, power and rebound performance of female volleyball players at the performance level
HARRISOVÁ, Helena Estella
The aim of the bachelor's thesis was to find out the influence of Red Bull energy drink on the speed, strength and rebound performance of female volleyball players at the performance level. Fifteen first-league volleyball players of VK Madeta České Budějovice club from the women's category were tested. The performance of female volleyball players was assessed using a bicycle ergometer, rebound board and hand dynamometer in the middle of the 2023/2024 season at the laboratory of load diagnostics at the department of physical education, University of South Bohemia. Each player underwent testing twice with a one-week break. Participants were given a Red Bull energy drink and a placebo in random order. Drinks were blinded. Anaerobic parameters were examined together with the blood lactate concentration using Wingate test, the average height recorded by the Bosc test and the maximum hand grip strength using the hand dynamometer. We did not confirm any significant effect of Red Bull energy drink on the observed performance. The t-test and Cohen's d were used to assess the statistical and substantive significance of the results. No significant effect of Red Bull energy drink on the observed parameters was found, with the exception of the maximum strength of the right-hand grip (d=0,29), the average height of the jump with a bounce from the left leg (d=0,22), maximum heart rate (d=0,29), maximum relative power (d=0,31), fatigue index (d=0,4) and lactate (d=0,2), for which substantive significant influence was recorded with only a small effect. Based on the evidence obtained from the measurements, it was proved that the Red Bull energy drink in a short period of time (20 min) had no effect on the performance of athletes.
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Performance optimisation of turbocharged engine for Formula Student
Špičák, Milan ; Janoušek, Michal (referee) ; Svída, David (advisor)
Diplomová práce je zaměřena na výběr pohonné jednotky pro Formuli Student, sestavení spolehlivého výpočtového modelu za využití pokročilého testování. Dále se zaměřuje na přípravu vhodných podmínek pro testování, samotné testování a následnou kalibraci řídicí jednotky pro validaci simulací a také pro efektivní a spolehlivé řízení motoru v náročných závodních podmínkách. Je zároveň součástí komplexního projektu, který se zabývá celkovým vývojem přeplňovaného jednoválcového motoru pro tým TU Brno Racing.
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Motor parameter identification for laboratory stand
Lidmila, Petr ; Kadlec, Josef (referee) ; Červinka, Dalibor (advisor)
The goal of introduced thesis is to provide measurement of the engines used as a tutorial laboratory stand in the course “Electric drives”. Due to the absence of appropriate measurement centre, the main emphasis is laid on the modernization of older dynymometer, which is going to be used by the students. Dynymometer has been equipped with the electric speed and torque vbmeasurement, data from these measurements are displayed and evaluated by the digital devices very clearly and precisely. Engines parameters measurements has only marginal importance in this thesis.
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Control circuits of eddy-current brake
Hofmann, Oldřich ; Knobloch, Jan (referee) ; Huták, Petr (advisor)
The thesis deals with the design of control circuits for the eddy-current brake, which will be used as main component of the dynamometer. The thesis focuses on the design of transistor inverter used for driving the eddy current brake and the design of speed regulation. The thesis also describes various types of brakes used in dynamometers and the overall concept of dynamometer electrical systems. An integral part of the thesis is also the test of the current controller and simulation of the control system at MATLAB – SIMULINK.
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Innovation of load test stand for electric drives
Martinek, Jan ; Marada, Tomáš (referee) ; Huzlík, Rostislav (advisor)
The theses presented proposes an innovation of load test stand for electric drives. It begins with a general overview of load test stand types, their manufacturers and measurement methods in load and no-load situations. Next part analyses current circuit diagram of the load test stand and its risks. This is followed by a proposal for innovation of the circuit diagram which is divided into electrical and control part using current load test stand and its mechanical parts. A wiring diagram is created, the control part is processed by the Logosoft program. The design is evaluated from the safety point of view and modified to meet applicable technical standards.
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Measurement of internal combustion engine performance on a chassis dynamometer
Farka, Jan ; Ramík, Pavel (referee) ; Štětina, Josef (advisor)
Since the beginning of the automotive industry, a lot of years have passed and the characteristics of vehicles and all its components, especially the engine, are being given greater and greater emphasis both in terms of safety, performance and ecology. The performance of the internal combustion engine, along with a number of other vehicle features, is measured on chassis dynamometers. The aim of the thesis is to describe and analyse the dynamometers produced, the tests performed on them and also to measure the performance of the internal combustion engine on the chassis dynamometer. In conclusion, the assessment of the impact of tests on the automotive industry is just mentioned.
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Race Car Measurement and Setup Devices
Andrys, Michal ; Blaťák, Ondřej (referee) ; Porteš, Petr (advisor)
This project deals with the systems and instruments used to measure and adjust the performance and effeciency of racing cars. The main goal of the work is to summarise the most widely used instruments for the basic and most important setup of the cars performance and the measurement of the most important components. It is concerned with tyres, wheels, engine and chassis.
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Experimental Identification of Brake System NVH
Drtílek, Juraj ; Blaťák, Ondřej (referee) ; Hejtmánek, Petr (advisor)
This Diploma Thesis is dedicated to solve the source of noise, observed during braking processes on tested vehicle, called Gouki noise and has been worked out in corporation with Federal Mogul company. The aim of this work to create test methology, which allows to experimentally detect the source of undesirable noise and eventually suggest next steps in its prevention.
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