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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Chassiintegrerade lastceller : Installation i fjädersäte på Scania tandemboggibakaxlar / Chassis integrated load cells : Installation in spring seat on Scania tandem boogies

Johansson, Gustaf January 2014 (has links)
The thesis presented in this report has been made on behalf of Scania and their basic frame design department with the subject to solve an implementation of a weight sensing system in the chassis. The system is supposed to be implemented in the seat springs, and the reason for this is that all the force will have to go through the weight sensing transducers. With all the force going through the transducers the weight sensing system will not be sensitive for the differences in tolerances from manufacturing. The transducers could be pre-calibrated to avoid a calibration of the whole vehicle after it’s completed from the manufacturing line. Weight sensing systems is today a reality in trucks with air springs. Complete systems is also sold in the big aftermarket for trucks. None of Scanias competitors have a solution for this as of today. The thesis was from start limited to only process the BT-301S bogie. A system will likely be easy to adapt to the other bogies with small modifications. Through the thesis possible problems are illuminated to understand the function and make a properly working weight sensing system. In the present bogie system the main problem for a proper function is the frictional forces that appears in the surface between the spring and the spring seat.  In the report a proposition with a rubber part between the spring and the spring seat is introduced, with the idea to get around the known problems with the frictional forces. The rubber itself does produce a reaction force when deformed, but the forces could through simulation be known, and hence compensated for. A rubber part under the spring would result in a contact surface much higher than today. A new spring, or a new version of the spring, will be needed for this solution to work. For the work to come, Scania need to decide what precision the weight sensing system need. But smaller decisions like the size and stiffness for the rubber part will also be needed. This thesis has only dealt with the bogie, but in a close future, the front axles need to be done. Much can likely be carried over from this thesis for that. A weight sensing might be possible to implement, but with what precision at uneven ground? Most likely will the variation in load on the transducers be too much. An approximation for the precision with a total span of 7% is realistic.
2

Electric Self Propelled Shoe : A shoe mountable last mile personal transportation vehicle / Elektriskt motordriven sko

Kårefjärd, Viktor, Stridfeldt, David January 2021 (has links)
The purpose of this work was to investigate how a last mile-transport vehicle can be constructed around a shoe. The prototype, which is controlled without a handheld controller, was designed to propel an adult forward with the use of an electric driveline. The user can easily stop driving, and instead walk short distances without removing the prototype. Research questions have been answered regarding how the battery and motor can be configured to reach a top speedof 15 km/h and a range of 3 km. In addition, answers were given as to how a user should control the vehicle’s speed in a safe and simple way, without the use of a handheld remote controller. The results show that the prototype reaches the specified top speed, and that the specified range is reached and exceeded. The user controls the motor power by moving their weight from the left to the right foot. The applied weight is measured by load cells under the heel, and after calibration, this user input method can be seen as satisfactory. The electric driveline, which is mounted under the shoe, allows the user to walk short distances without removing the prototype. Future work may add safety equipment such as lamps and a bell to make the product legal for use in public areas. In addition, a left shoe needs to be developed further, due to how the concept is dependent on it to function optimally. / Det här arbetet hade till avsikt att undersöka hur ett sistasträckan-fordon kan konstrueras kring en sko. Prototypen, vilken styrs utan en handkontroller, utformades för att förflytta en vuxen person med hjälp av en elektrisk drivlina. Användaren kan enkelt sluta åka, och istället gå kortare sträckor utan att ta av sig prototypen. Forskningsfrågor har besvarats angående hur batteri och motor kan konfigureras för att uppnå topphastigheten 15km/h och färdsträckan 3 km. Dessutom besvarades hur en användare ska kontrollera fordonets hastighet på ett säkert och enkelt sätt, utan användning av en handkontroll. Resultaten visar att prototypen uppnår topphastigheten, och att den angivna räckvidden uppnås och överskrids. Användaren styr motoreffekten genom att förflytta sin vikt från vänster till höger fot. Den applicerade vikten mäts av lastceller under hälen, och efter kalibrering kan denna användar-inmatningsmetod ses som tillfredsställande. Den elektriska drivlinan, som monteras under skon, tillåter att användaren går kortare sträckor utan att ta av sig prototypen. Framtida arbete kan tillägga säkerhetsutrustning, som lampor och ringklocka för att göra produkten laglig för användning på allmän plats. Dessutom behöver en vänstersko utvecklas mer, på grund av hur konceptet är beroende av denna för att fungera optimalt.

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