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A Novel Method for ...
A Novel Method for Quantifying Ski-Snow Friction Using an Rtk-Gnss Equipped Sled
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- Kalliorinne, Kalle, 1995- (författare)
- Luleå tekniska universitet,Maskinelement
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- Sandberg, Joakim (författare)
- Luleå tekniska universitet,Maskinelement
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- Hindér, Gustav (författare)
- Luleå tekniska universitet,Maskinelement
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- Holmberg, Hans-Christer, 1958- (författare)
- Luleå tekniska universitet,Hälsa, medicin och rehabilitering
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- Supej, Matej (författare)
- University of Ljubljana, Slovenia
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- Larsson, Roland (författare)
- Luleå tekniska universitet,Maskinelement
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- Almqvist, Andreas (författare)
- Luleå tekniska universitet,Maskinelement
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(creator_code:org_t)
- Engelska.
- Relaterad länk:
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https://doi.org/10.2...
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https://urn.kb.se/re...
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https://doi.org/10.2...
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Abstract
Ämnesord
Stäng
- In most winter sports, the athletes interact with snow with their equipment. In some of these sport, e.g. in cross-country skiing, a large amount of energy is spent by the athlete to overcome the restive force of friction. Consequently, a reduction in friction can be the difference between winning and coming second in a race. Over the years, researchers have come up with many ways of measuring the friction between snow and sports equipment, such as different types of skis. However, only a few of these experimental setups can be used to test the glide of real-sized skis under natural conditions during both accelerating and deceleration motion. In the present work, a novel experimental setup consisting of a sled and a base station that uses GNSS receivers communicating internally by radio, thus making up an RTK-GNSS system which can measure the position of the sled with centimetre accuracy, was established. The sled is equipped with authentic cross-country skis and accelerated and decelerated on a track with natural height variation prepared with a conventional snow-track setter mounted on a snowcat. The recorded altitude and velocity data are used to quantify the coefficient of friction (COF), both for accelerating and decelerating motion, with a model based on the preservation of energy. The results show that the COF during acceleration was more than 28% higher than during deceleration, while the difference in the COF during deceleration on flat ground at loading conditions resembling the acceleration and deceleration phases was less than 5%. This is an important discovery, as when all types of skiing techniques are executed, the athlete is either accelerating or decelerating while moving forward along the track. The ability of the current experimental set-up to distinguish between them may thus have positive implications for further development.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Maskinteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Mechanical Engineering (hsv//eng)
Nyckelord
- Winter Sports
- Cross-Country Ski
- Snow
- Friction
- RTK-GNSS
- Sled
- Machine Elements
- Maskinelement
Publikations- och innehållstyp
- vet (ämneskategori)
- ovr (ämneskategori)