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This work was created in cooperation with company Mubea. Introduction part describes purpose of automotive headrest and function of special grooves, which are fitted on headrest frame. Overview of manufacturing technologies of these grooves with short summary of their advantages and disadvantages follows. The main part of this work consists of development of new alternative technology for manufacture special grooves in thin-walled tubes with following experimental verification of technological conditions and shape of grooves. This work also contains evaluation of tool life and wear. Interpretation of the results is performed by calculations and graphically.

A bachelor thesis conducted over the spring term of 2018, the final exam of the Innovation and Design Engineering program at Karlstad University. The contractor of this thesis project was Parfum Lombard AB in Svedala, Sweden, a market leading within the hairdressing equipment industry in Sweden. They provide a high level of innovation and product development to improve its assortment.   The project of this thesis will focus on the frequent used shampoo units at the hair salons in particular. The shampoo units will be analyzed from an ergonomic point of view, because the current sitting position can cause discomfort and pain for customers with neck problems. Today, neck and back pain are amongst the most common chronic pains issues, which requires further development of this type of equipment in order to make it more suited for the end-user. The chosen target group for the project are people with neck-related disabilities as the starting point for formulating the design problem and developing the solution.   The main objective of the project is to develop a concept that offers the customer a more ergonomic position, while washing the hair at the salon. By following a user-centered product development process, the problem will be addressed in the following parts: Pre-study, product specification, idea generation, concept development and finally construction in the layout design phase. The product specification forms a key part, which as a dynamic document links together both customers, clients and professionals perspective of the issue, and underlines the final concept selection.   Key findings: To improve the current washing position the sharp angle between the upper body and the head needs to be reduced. That could be solved in two ways; The backboard of the upper body leans back even further to accomplish a more recumbent position or by an additional support to the neck in order to gain a more up-right position. The last mentioned, which also represent the final concept ensures that not only the neck is supported but also the head. This means that the heavy load that the head’s own weight previously caused has now been drastically reduced.   The presented concept in the report differs from the similar existing product by its support surface. It provides a wider support area to the customer’s neck and head. With a slim design that only depends on a few centimeters of the basin´s geometry, the chances of matching as many models of shampoo units as possible increases. The developed concept are presented in both CAD- and mock-up models.

This diploma thesis was created in cooperation with Mubea company. It deals with proposal of alternative technology of groove deburring. A special tool was designed for this technology and was experimentally tested. There are also tests for finding suitable cutting conditions, tests for appropriate tool’s positioning against a workpiece and tests for comparison the alternative technology of groove deburring to grinding technology included in this diploma thesis

This dissertation is concerned with the active control of local sound fields, as applied to an active headrest system. Using loudspeakers and microphones, an active headrest is capable of attenuating ambient noise and providing a comfortable acoustic environment for an occupant. A finite element (FE) model of an active headrest is built and analyzed such that the expected noise reduction levels could be quantified for various geometries as well as primary sound field conditions. Both plane wave and diffuse primary sound fields are considered and it is shown that the performance deteriorates for diffuse sound fields. It is then demonstrated that virtual sensing can greatly improve the spatial extent of the quiet zones as well as the attenuation levels. A prototype of the active headrest was constructed, with characteristics similar to those of the FE model, and tested in both anechoic and reverberant sound fields. Multichannel feedforward and feedback control architectures are implemented in real-time and it is shown that adaptive feedback systems are capable of attenuating band-limited disturbances. The spatial attenuation pattern surrounding the head is also measured by shifting the head to various positions and measuring the attenuation at the ears. Two virtual sensing techniques are compared in both feedback and feedforward architectures. The virtual microphone arrangement, which assumes that the primary sound field is equivalent at the physical and virtual locations, results in the best performance when used in a feedback system attenuating broadband disturbances. The remote microphone technique, which accounts for the transfer response between the physical and virtual locations, offers the best performance for tonal primary sound fields. In broadband sound fields, a causal relationship rarely exists between the physical and virtual microphones, resulting in poor performance. / PHD

Thesis in the field of passive safety problems, traffic accidents and health outcomes of participants in road traffic accidents is aimed, inter alia, to create an overview of modern passive safety elements especially cars. The work deals with elements of the passive safety system and the impact on the crew vehicle. It describes the principle of operation, especially airbags, safety belts, belt pretensioner and it includes solution of limiters tensioning force in the safety belt and other elements that have the task of reducing the consequences of a traffic accident. The use of modern elements of passive safety provides increased protection for the crew and eliminates the formation injuries crew. The technical issue is therefore closely related to the healthcare industry and in particular the Court of medicine in the field of personal injury in relation to the types and characters of incidents, or by applying of the safety elements. There are also shown the actual road accidents in which were killed or injured members of crew with an analysis of the mechanism of injury with the use or non-use of safety elements.

Truck drivers spend long, consecutive periods of time seated down, and the truck cab becomes their immediate work environment. Therefore, it is important to make sure that this space is properly adapted to fit the driver’s needs well. The driver seat is something the driver are very much in contact with. The seat can be adjusted in many ways to accommodate for drivers of different heights and body types. However, two of the components which are fixed today are the upper seat belt anchorage position and the headrest. In this thesis project, the aim has been to investigate the adjustment possibilities of these components in terms of desired adjustment range and mechanical solutions. The first part of the project was spent on ergonomic evaluations of the seat, and finding what properties are the most important when designing a truck seat. Both literature reviews as well as interviews and observations helped build the knowledge foundation to base adjustment concepts on. For example, it was found that to minimise the negative effects of sedentary work, the single most important action is to frequently change the sitting position. Therefore, it is of high importance that adjustment procedures are as simple as possible. It was also found that many truck drivers do not use their seat belt at all, and that having a headrest which is adjustable in height is important for the driver’s visual area. Several ideas and concepts were generated and evaluated. The initial ideas included both solutions applicable on the current seat belt design, while some would use other means of securing the driver in a collision. The ideas were compared and evaluated, and three were chosen to develop further; one being easy to implement, and two being mechanical solutions both making use of the current seat belt design. These three concepts were investigated more deeply, and were subsequently also compared using different methods for evaluation. Eventually, a final concept was chosen; a mechanical solution in which the seat belt and headrest can be adjusted separately in one and two directions respectively. This concept was further developed in terms of both mechanical as well as visual design. In the final concept, Hoop, the seat belt is adjusted sideways, as this was proven to give the largest comfortability improvement for the driver. The headrest is adjustable in both height and depth. The mechanisms are locked using ratchets, however, both can be adjusted in what is believed to be the most critical direction without the need to unlock first. The buttons for unlocking the mechanisms are placed directly on the adjustment mechanisms in order to keep the procedure as intuitive and easy to use as possible. The adjustment ranges were determined based on Scania’s anthropometric dataset in order to make sure that the adjustment features will be useful for an as large part of the driver population as possible. / Lastbilschaufförer tillbringar under sina arbetspass många timmar i lastbilshytten, som blir deras direkta arbetsmiljö. Det är därför viktigt att hytten är utformad utifrån föraren och dennes behov. Förarstolen är en av de komponenter som föraren har allra mest kontakt med. Denna kan justeras på många sätt för att möjliggöra för förare av olika längder och kroppstyper att hitta en körposition som passar just dem. Två komponenter som dock inte kan justeras i dagsläget är positionen av den övre bältesomlänkaren och nackstödet. I detta examensarbete har fokus varit att ta fram hur justering för dessa skulle kunna se ut både i form av önskat justerområde och mekaniska lösningar. Projektets inleddes med en ergonomisk undersökning för att hitta de viktigaste fokusområdena för just lastbilars förarstolar. Informationen hämtades dels från litteratur, och utöver detta gjordes även användarundersökningar genom en enkät, kontextuella intervjuer och observationer. En av de viktigaste insikterna från undersökningen var att det absolut viktigaste för att undvika negativa effekter av stillasittande arbete är att kontinuerligt ändra sin sittposition. Ett effektivt sätt att få fler förare att använda justeringsfunktionerna på detta sätt kan vara att placera kontroller väl åtkomliga och göra justeringsproceduren så lättförståelig och lättanvänd som möjligt. Dessutom är det mycket viktigt att ett nackstöd kan justeras inte bara ur komfortsynpunkt, utan här finns det även en stark säkerhetsfaktor kopplad till förarens synfält. Baserat på informationssökningen genererades därefter flera olika lösningsidéer, där vissa låg närmre dagens lösning än andra. Dessa evaluerades sedan med hjälp av bland annat beslutsmatriser, och tre idéer valdes att utveckla vidare till tydligare koncept. Av de tre idéer som valts ut var en lösning enkel att implementera och två var olika mekaniska lösningar, alla applicerbara för den nuvarande bältesformen. Dessa detaljerades och kombinerades samman med hjälp av en morfologisk matris, och jämfördes sedan gentemot varandra. Slutligen valdes ett koncept ut som det slutgiltiga, där bältesomlänkaren kan justeras i en riktning och nackstödet i två. Detta slutkoncept utvecklades ytterligare vad gäller den mekaniska lösningen och dess visuella form. I slutkonceptet, Hoop, kan bältesomlänkaren justeras i sidled, eftersom denna justeringsriktning i den ergonomiska undersökningen visade sig ge störst resultat för förarens komfort. Nackstödet kan justeras både i höjd- och i djupled. Båda mekanismerna låses med hjälp av geometriska spärrlåsningar, men kan justeras i en riktning, den som ses som mest kritisk att snabbt kunna justera i, utan att föraren först behöver låsa upp mekanismen. Knapparna för att låsa upp mekanismerna är placerade i direkt anslutning till området där själva rörelsen sker för att göra användandet så intuitivt som möjligt. Justerområdena har baserats på antropometriska mått hämtade från Scaniafamiljen för att försäkra om att de täcker in så stor del av förarpopulationen som möjligt.