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Megnetorheological shockabsorber
Lazar, Jaroslav ; Růžička, Bronislav (referee) ; Mazůrek, Ivan (advisor)
This master's thesis deals with an engineering design of an external reservoir for hydraulic shock absorbers with combined filling of oil and magnetorheological fluid. The first part describes existing designes of magnetorheological shock absorbers and characteristics of magnetorheological fluid. Next part describes a design of an experimental external reservoir and a test of its functionality on a prototype. This is followed by an optimalized engineering design of the experimental external reservoir.
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Magnetorheological Suspension Damper for Space Application
Kubík, Michal ; Porteš, Petr (referee) ; dr hab. inż. Janusz Gołdasz, prof. PK (referee) ; Mazůrek, Ivan (advisor)
Disertační se práce se zabývala vývojem magnetoreologického (MR) tlumiče odpružení pro kosmonautiku. Dle současného stavu poznání jsou důležitými parametry pro semi-aktivně řízený tlumič pro kosmonautiku hermetické oddělení pracovní kapaliny od zbytku nosiče a krátká časová odezva tlumícího elementu. Těmto požadavkům vyhovuje magnetoreologický tlumič s vlnovcovou jednotkou. Magnetický obvod MR tlumiče pro kosmonautiku byl vyroben z feritového materiálu, který umožnil výrazně snížit časovou odezvu. Hermetičnost byla zajištěna použitím vlnovcové jednotky. Konstrukce takového typu tlumiče ovšem přináší celou řadu problémů. Vyvinutý MR tlumič s feritovým magnetickým obvodem dosahoval časové odezvy 4.1 ms a dynamického rozsahu 8. Během konstrukčních prací na MR tlumiči pro kosmonautiku byly hledány nové metody pro konstrukci semi-aktivně řízeného MR tlumiče s krátkou časovou odezvou. Konkrétně se jednalo o metodu eliminace vířivých proudů v magnetickém obvodu MR tlumiče, magnetostatický a transietní magnetický model, CFD model obtokové štěrbiny, hydraulický model MR tlumiče a jejich experimentální verifikace. Tyto nové metody umožní konstrukci MR tlumiče pro kosmonautiku lehčí, s nižší časovou odezvou a vyšším dynamickým rozsahem.
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Design of magnetorheological damper with asymmetric velocity characteristic
Válek, Josef ; Macháček, Ondřej (referee) ; Kubík, Michal (advisor)
This thesis aims to find optimal solution for magnetorheological damper with asymmetric force-velocity behaviour. Magnetorheological dampers represent a promising direction in the development of vibration dampers, mainly due to their adjustable damping, that depends on electric current. The asymmetric force-velocity behaviour (characteristic) then means difference while compressing or expanding damper and can be achieved by valves. Valves can be solved in mechanical, hydraulic, magnetic, electric way. This bachelor´s thesis evaluates these four ways of solution and develops conceptual solutions for their possible application. One conceptual solution is then elaborated in detail. Chosen mechanical solution with movable plate was verified by calculations and experiment. Experiments confirmed the applicability of a mechanical valve in magnetorheological systems.
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Integration of stroke sensor into the front bike fork
Pešout, Richard ; Jeniš, Filip (referee) ; Strecker, Zbyněk (advisor)
This bachelor's thesis deals with the design of the installation of the iC-MHL200 sensor in the front suspension fork of a bike, where it will measure the stroke in order to control a magnetorological damper. The thesis first describes selected suspension systems, currently available systems enabling the measurement of bike fork lift and the iC-MHL200 sensor itself. Furthermore, the thesis deals with the design and production of a test holder, the sensor test and its results. Using the results, the installation design itself was subsequently created. During the design, it was necessary to overcome several obstacles, which was achieved with certain compromises and the goal of the thesis was fulfilled. This installation will allow further, more accurate testing of the sensor and later also the control of MR dampers with an affordable but accurate sensor.
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Magnetorheological shock absorber with short response time for train bogie
Šebesta, Karel ; Špalek, Petr (referee) ; Kubík, Michal (advisor)
The diploma thesis deals with the design of a magnetorheological damper with a short response time of the damping force for the bogie of a rail vehicle. The largest component, which slows down the response, is the eddy currents generated in the piston group of the MR damper. A rapid onset of damping force is achieved by using a shape approach in magnetic circuit design. The shape approach increases the distance that the eddy currents must travel, and therefore it helps to reduce them. The shape approach is realized by grooving the core and the shell of the MR damper. The proposed fast version of the MR damper is measured on a hydraulic pulsator and its results show a sufficient time response of the damping force. This response does not exceed 8 ms for the primary onset of the damping force. The new fast design of the MR damper combines the greatest advantages of the technology and enables to meet new requirements for damping elements in the rolling stock chassis.
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Design of semiactive seat suspension for agricultural machines
Zindulka, Martin ; Čížek, Petr (referee) ; Strecker, Zbyněk (advisor)
The thesis deals with design of a semiactive seat suspension system for an agriculture machines and design of dynamic model of the system, which includes real parameters of a magnetorheological (MR) damper. The dynamic model is a single degree of freedom model and it is made in program Matlab. In the model, response time of the MR damper and three control algorithms are implemented (two-state Skyhook, Skyhook linear approximation damper control and Acceleration Driven Damper control). Based on the results of the simulations, the damping characteristics are defined, and the MR damper is modified to achieve fast response time. A test seat is designed to test transmission of vibrations to the driver. The simulation results provide a comparison of efficiency of the seat suspension depending on the response time and control algorithm, as well as a comparison with a passive suspension system. On the designed test seat with MR damper with a fast response time, the vibration transmission is reduced up to 25 % compared with the best passive seat suspension setup.
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Adaptive control of magnetorheological dampers
Míša, Jiří ; Porteš, Petr (referee) ; Zháňal, Lubor (advisor)
The topic of this master´s thesis is the design of adaptive damping algorithm for the prototype magnetorheological dampers, which are used for Formula Student vehicle. The prime output is the development and optimization of the control algorithm which included usage of the MBS software and real data from race track. Temperature compensation to supress the effect of dynamic viscosity of magnetorheological fluid due to the increase in operating temperature and testing of the vertical dynamic of the car on 4 - post test rig was realized as well. The main goal was to obtain better control of the car in transient situations and increase usability of tires via changes in damping based on actual conditions and status of the vehicle.
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Design of magnetorheological damper with asymmetric velocity characteristic
Válek, Josef ; Macháček, Ondřej (referee) ; Kubík, Michal (advisor)
This thesis aims to find optimal solution for magnetorheological damper with asymmetric force-velocity behaviour. Magnetorheological dampers represent a promising direction in the development of vibration dampers, mainly due to their adjustable damping, that depends on electric current. The asymmetric force-velocity behaviour (characteristic) then means difference while compressing or expanding damper and can be achieved by valves. Valves can be solved in mechanical, hydraulic, magnetic, electric way. This bachelor´s thesis evaluates these four ways of solution and develops conceptual solutions for their possible application. One conceptual solution is then elaborated in detail. Chosen mechanical solution with movable plate was verified by calculations and experiment. Experiments confirmed the applicability of a mechanical valve in magnetorheological systems.
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Reconstruction of undetachable LORD MR damper
Lochman, Vít ; Macháček, Ondřej (referee) ; Mazůrek, Ivan (advisor)
The bachelor´s thesis deals with the design and the realization of the modification of the non-demountable magnetorheological damper LORD, which has gained an atypical Fv characteristic in the course of time. The first part of the thesis deals with the operation of the magnetorheological liquid and the various design variants of the magnetorheological dampers. The practical part is devoted to the reverse engineering and the design of the damper modification itself. The complete drawing documentation of the original and the modified damper is included in this work.
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