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Design of DH bike fork with magnetorheological damper
Salva, Matúš ; Robenek, Dětřich (oponent) ; Strecker, Zbyněk (vedoucí práce)
When mountain biking over rough terrain, comfort and sufficient wheel pressure are often the limiting factors. That's why there is an effort to innovate suspension and develop dampers that provide better damping characteristics. The usage of semi-active suspension is one way to achieve the desired improvement over the currently used passive systems. In this work, the aim was to develop a magnetorheological damper that is suitable for implementation in commonly available mountain bike forks and whose damping characteristics allow the use of the Skyhook algorithm. A functional model of an MR damper with a stroke of 240 mm and an outer diameter of 29.5 mm, whose dynamic range is 9.5 at a piston velocity of 0.25 ms-1 and a time response of 17 ms, was developed. The magnetic circuit of the manufactured functional pattern is of 11SMn30. The damper served to verify the functionality of the concept and at the same time its damping characteristics were experimentally verified and compared with the predicted values. Due to the combination of numerical and analytical model, a very good agreement between prediction and experiment was achieved. Hence, an MR damper with a magnetic circuit made of Hiperco/Vacoflux 50 material was subsequently designed with a predicted dynamic range of 9.5 and a time response of less than 10 ms. The resulting total weight of the design is 0.68 kg. This design fully satisfies all requirements. When used in combination with semi-active control using the Skyhook algorithm, it is predicted to improve ride comfort by 28 %. The potential to use the proposed MR damper is with the increasingly widespread electric bicycles mainly due to the higher weight in conjunction. At the same time, however, the possibility of using it on a regular bicycle is not excluded. Semi-active suspension is a new and not yet widely used technology in cycling and has the potential to reach a new range of consumers. Considering all the advantages and disadvantages, it can be concluded that the proposed MR shock absorber allows to improve the rideability of mountain bikes both in terms of ride comfort, wheel traction or in the form of reduced energy expenditure during pedalling due to energy absorption by the suspension.
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Návrh konstrukce MR tlumiče do odpružené vidlice kola
Salva, Matúš ; Macháček, Ondřej (oponent) ; Strecker, Zbyněk (vedoucí práce)
V horskej cyklistike je predné odpruženie dôležitý komponent, ktorý zaisťuje komfort a bezpečnosť jazdy. Táto bakalárska práca sa zaoberá návrhom semiaktívneho odpruženia, ktoré zvláda tieto úlohy lepšie ako v cyklistike bežne používané adaptívne odpruženie. Za týmto účelom boli vytvorené simulačné modely odpruženia s adaptívnym odpružením a so semiaktívnym odpružením obsahujúcim MR tlmič s riadiacim algoritmom Skyhook. Na základe simulácie bol vytvorený optimálny silový rozsah MR tlmiča pre použitie v horskej cyklistike. Výsledky simulácie MR tlmiča boli ďalej porovnané s výsledkami simulácie odpruženia obsahujúceho experimentálne zistené F-v charakteristiky adaptívneho tlmiča, použitého v zjazdovom bicykli. MR tlmič v kombinácii s algoritmom Skyhook dosiahol lepšie výsledky v oblasti jazdného komfortu a zachoval adhéziu predného kolesa rovnakú ako v prípade použitia adaptívneho tlmiča. Výsledný silový rozsah je možné použiť k ďalšiemu testovaniu, prípadne ku konštrukcii MR tlmiča vhodného do vidlice horského bicykla.
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Design of DH bike fork with magnetorheological damper
Salva, Matúš ; Robenek, Dětřich (oponent) ; Strecker, Zbyněk (vedoucí práce)
When mountain biking over rough terrain, comfort and sufficient wheel pressure are often the limiting factors. That's why there is an effort to innovate suspension and develop dampers that provide better damping characteristics. The usage of semi-active suspension is one way to achieve the desired improvement over the currently used passive systems. In this work, the aim was to develop a magnetorheological damper that is suitable for implementation in commonly available mountain bike forks and whose damping characteristics allow the use of the Skyhook algorithm. A functional model of an MR damper with a stroke of 240 mm and an outer diameter of 29.5 mm, whose dynamic range is 9.5 at a piston velocity of 0.25 ms-1 and a time response of 17 ms, was developed. The magnetic circuit of the manufactured functional pattern is of 11SMn30. The damper served to verify the functionality of the concept and at the same time its damping characteristics were experimentally verified and compared with the predicted values. Due to the combination of numerical and analytical model, a very good agreement between prediction and experiment was achieved. Hence, an MR damper with a magnetic circuit made of Hiperco/Vacoflux 50 material was subsequently designed with a predicted dynamic range of 9.5 and a time response of less than 10 ms. The resulting total weight of the design is 0.68 kg. This design fully satisfies all requirements. When used in combination with semi-active control using the Skyhook algorithm, it is predicted to improve ride comfort by 28 %. The potential to use the proposed MR damper is with the increasingly widespread electric bicycles mainly due to the higher weight in conjunction. At the same time, however, the possibility of using it on a regular bicycle is not excluded. Semi-active suspension is a new and not yet widely used technology in cycling and has the potential to reach a new range of consumers. Considering all the advantages and disadvantages, it can be concluded that the proposed MR shock absorber allows to improve the rideability of mountain bikes both in terms of ride comfort, wheel traction or in the form of reduced energy expenditure during pedalling due to energy absorption by the suspension.
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Návrh konstrukce MR tlumiče do odpružené vidlice kola
Salva, Matúš ; Macháček, Ondřej (oponent) ; Strecker, Zbyněk (vedoucí práce)
V horskej cyklistike je predné odpruženie dôležitý komponent, ktorý zaisťuje komfort a bezpečnosť jazdy. Táto bakalárska práca sa zaoberá návrhom semiaktívneho odpruženia, ktoré zvláda tieto úlohy lepšie ako v cyklistike bežne používané adaptívne odpruženie. Za týmto účelom boli vytvorené simulačné modely odpruženia s adaptívnym odpružením a so semiaktívnym odpružením obsahujúcim MR tlmič s riadiacim algoritmom Skyhook. Na základe simulácie bol vytvorený optimálny silový rozsah MR tlmiča pre použitie v horskej cyklistike. Výsledky simulácie MR tlmiča boli ďalej porovnané s výsledkami simulácie odpruženia obsahujúceho experimentálne zistené F-v charakteristiky adaptívneho tlmiča, použitého v zjazdovom bicykli. MR tlmič v kombinácii s algoritmom Skyhook dosiahol lepšie výsledky v oblasti jazdného komfortu a zachoval adhéziu predného kolesa rovnakú ako v prípade použitia adaptívneho tlmiča. Výsledný silový rozsah je možné použiť k ďalšiemu testovaniu, prípadne ku konštrukcii MR tlmiča vhodného do vidlice horského bicykla.
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