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Vehicle Level EMC Performance Prediction from Component Test Results
No full textThis thesis investigates the feasibility of predicting vehicle-level Electromagnetic Compatibility (EMC) performance from component-level testing and simulation. Using an automotive wiper drive system as the case study, the work aims to reduce dependence on costly and time-consuming whole- vehicle EMC tests by establishing an integrated methodology combining empirical measurement and numerical modeling. Component-level conducted and radiated emission tests were performed in accordance with Comité International Spécial des Perturbations Radioélectriques (CISPR) 25, and the measured common-mode currents were used as excitation sources in Computer Simulation Technology (CST) Studio Suite simulations. The correlation between measured and simulated electric fields in the 150 kHz–30 MHz range showed close agreement, confirming that measurement-driven source modeling can accurately reproduce radiated emission behavior. The validated component model was then extended to a full-vehicle electromagnetic simulation, where near-field coupling and grounding effects were analyzed. Results indicate that component-based models can qualitatively predict vehicle-level trends, offering engineers an early-stage diagnostic tool for identifying potential EMC risks. Although full substitution of physical vehicle testing remains challenging due to modeling and computational limitations, the proposed hybrid workflow demonstrates a practical
pathway toward simulation-supported EMC development, aligning with the auto motive industry’s goals for faster, more efficient, and cost-effective design validation
Cleaning and reuse of engine oil
No full textThis thesis investigates the management of waste oil at Volvo Trucks and evaluates the potential of adopting more sustainable practices, particularly through use of re-refined base oil (RRBO). As
sustainability becomes increasingly critical in the automotive industry, the effective handling of waste materials, such as engine oil, is essential for both environmental responsibility and cost effectiveness.
The current management practices at Volvo Trucks reveal a significant gap in knowledge regarding the fate of waste oil after collection. Workshops often lack clarity in their contracts with recycling companies
and the following processing of the oil.
This thesis aims to broaden the understanding of waste oil management practices, regulatory frameworks, and the potential for integrating RRBO into new engine oil formulations.
Through surveys and field visits to various workshops across Europe, data was collected on waste oil storage, collection practices, and financial arrangements with recycling companies.
The findings indicate a diverse range of practices, with many workshops demonstrating a commitment to proper waste oil management, while others exhibit inconsistencies that could hinder recycling efforts.
The analysis highlights the environmental benefits of utilizing RRBO, which can significantly reduce carbon emissions compared to incineration. However, the ability to incorporate RRBO into Volvo's
products depends on the practices of oil producers, necessitating further testing and validation.
In conclusion, this thesis provides valuable insights into the current state of waste engine oil management at Volvo Trucks and outlines actionable recommendations for enhancing sustainability
practices. By standardizing procedures and exploring the integration of RRBO, Volvo can strengthen its commitment to environmental responsibility and improve its market reputation
Temperature Prediction in Car Lamps Using Sun Load Data. A simulation model development study for the rear lamps of the Volvo EX90
No full textHeat-sensitive materials and components, such as batteries, sensors, cameras, and polymeric materials, are a significant part of most cars on the market. To avoid damage to these parts, it is important to know what temperatures they will be subjected to. Sun Load Data (SLD) uses loads generated by the sun, solar radiation, to predict temperatures in different areas of the car.
This thesis aims to conduct an SLD study using a detailed rear lamp model of the Volvo EX90, which also includes the different material properties for each component, such as emissivity, transmittance, reflectivity and absorptivity. The material properties of the different components that make up the lamp will be measured and used as part of the input parameters. Different types of convection (using the lump capacitance model 0−D or 3−D) are simulated and compared, taking into account the level of accuracy and runtime. Different days are also selected to be used as the input weather file, making an attempt at extending the correlation to days when the ambient or part temperature is the highest. The effect of the external wind as well as the LED light source on the temperature readings are also taken into account.
The developed virtual model can be used in the early development phase for requirement setting, material choice, and the geometric design of the lamp. It can be used as an early checkpoint to decide whether the aforementioned parameters are ideal.
This will therefore eliminate the situation where the vehicle is already in the physical testing phase, and the lamp experiences performance or aesthetic failure. Areas with potential for improvement are discussed together with their probable reasons, along with actions to mitigate them
Arbetstillfredsställelse och motivation inom byggbranschen: En kvalitativ undersökning av yrkesmedarbetarnas arbetsmiljö med avseende på motivation och trivsel
No full textSyftet med examensarbetet var att undersöka faktorer som påverkar
arbetstillfredsställelse och motivation hos yrkesmedarbetare inom byggbranschen.
Målet var att utifrån dessa identifiera potentiella förbättringsåtgärder för att sedan
kunna öka arbetstillfredsställelsen och motivationen hos yrkesmedarbetarna.
För att besvara syftet och frågeställningarna genomfördes både en litteraturstudie och
kvalitativa intervjuer. Totalt genomfördes tio semistrukturerade intervjuer med
yrkesmedarbetare på ett svenskt byggföretag. Intervjuerna baserades på områden som
framkommit som viktiga utifrån litteraturstudien samt relevanta utifrån företagets
medarbetarenkäter. Områdena som undersöktes var kommunikation, feedback,
planering, ledarskap och engagemang samt sammanhållning.
Resultaten visade att yrkesmedarbetarna trivs på företaget. Det framkom att
arbetstillfredsställelse och motivationen påverkades positivt av stark teamkänsla,
varierade arbetsuppgifter, autonomi, feedback och uppskattning. Brist i planering,
otydlig kommunikation och brist på återkoppling var faktorer som kunde upplevas
negativt. Bemötandet upplevdes generellt gott men det fanns vissa
kommunikationsutmaningar som främst handlade om brist på information. En del av
respondenterna efterfrågade mer feedback, bättre framförhållning i planeringen och
ökad närvaro från chefer. Även sammanhållning var en tydlig motivationsfaktor. Att
öka lyhördheten, ge mer information, öka närvaron från tjänstemän och ge mer
feedback är förslag för att öka arbetstillfredsställelsen och motivationen hos
yrkesmedarbetarna.
Det är individuellt och skiljer sig åt vad olika yrkesmedarbetare uppskattar och anser är
viktigt inom de olika områdena. Därav är det viktigt att stämma av med var och en för
att kunna anpassa detta utifrån varje individ
Assessing the Energy Impact of Java Software Debloating Tools
No full textContext: Software debloating tools are commonly used to reduce application size, minimize attack surface, and enhance performance, but may also offer potential for lowering energy consumption in Java applications.
Objectives: This study examines the energy-related impact of four Java debloating tools—ProGuard, DepClean, DepTrim, and JLink—by quantifying their effects on energy consumption and identifying factors that influence the energy use of debloated Java applications.
Methods: An empirical evaluation was conducted on 10 benchmark Java projects and 5 real-world Java applications. For each system, CPU and memory usage, execution time, power draw, and total energy consumption were measured across 30 independent trials, comparing debloated versions produced by each tool against the original baseline.
Results: Across all systems, energy and performance metrics remained largely consistent between debloated and baseline versions. While tool effectiveness varied by project, DepTrim achieved the greatest mean energy reduction, with a decrease of 0.80% in real-world applications.
Conclusion: The evaluated Java debloating tools yielded minimal improvements in energy efficiency and impact on the performance metrics for the tested systems, despite employing varied optimization strategies. These findings highlight the need for more energy-conscious debloating techniques and robust evaluation frameworks to promote sustainable software engineering practices. The methodology presented in this study can serve as a foundation for future work at the intersection of energy consumption measurement and software debloating strategies
Statistical Shape Modeling of the First Human Rib: Modeling Using CT Data and Demographic Predictors
No full textThe first human rib plays a critical role in thoracic biomechanics and is increasingly
relevant for improving simulations in human body models used in vehicle and traffic
safety research. This thesis aims to develop a statistical shape model (SSM) of the
first rib that captures morphological variability in terms of sex, age, height, and
body mass index (BMI), based on computed tomography (CT) data.
A total of 50 anonymized CT scans, sourced from a trauma hospital through
the University of Michigan, were used from an available dataset of 104 samples.
The workflow included segmentation in 3D-Slicer, landmarking in ANSA, and
cortical bone thickness mapping using Stradview. To enable statistical analysis, a
template rib surface was morphed to match each segmented rib using the Infepy
Python library, so that all surfaces shared the same number and arrangement of
nodes. Rib thickness values were also transferred onto these common nodes to
combine shape and cortical thickness data. Generalized Procrustes Analysis (GPA)
and Principal Component Analysis (PCA) were performed to align the ribs and
identify dominant modes of variation, respectively. Linear regression was employed
to examine relationships between principal component scores and demographic
variables, and to predict shape and thickness parameters, which were then used to
reconstruct corresponding 3D meshes.
Four principal components showed statistically significant correlations (p ≤ 0.05)
with demographic variables (age, sex, height, and BMI) in regression analysis.
These components primarily encoded variation in rib size, cortical thickness, and
subtle shape changes. However, age, sex, height, and BMI alone could capture only
15% of the total variability, indicating that these parameters were insufficient to
fully predict rib morphology.
Despite these limitations, the resulting model represents a valuable step toward
anatomically realistic rib shape modeling and offers potential for enhancing
personalized simulations in safety engineering. Additionally, PCA proved useful
beyond model building by enabling quantification and visualization of how rib
morphology varies across individuals
Undersökning av hydroxylapatits inverkan på magnesiumytor i kroppens miljö genom atomskaliga beräkningar
No full textMagnesium visar stor potential att användas som ett material i nedbrytbara implantat
för benstabilisering. Då magnesium lätt korroderar är det aktuellt att öka korrosionsmotståndet
genom legering eller ytbehandling. I detta arbete används density
functional theory (DFT) för att undersöka om ytbehandlingen hydroxylapatit (HAp)
binder till en Mg(0001)-yta, både med och utan legering, och om det påverkar korrosionsmotståndet.
I vakuum binder HAp till magnesiumytan, och bindningen förstärks
ytterligare vid zinkdopning samt när det översta lagret består av magnesiumhydroxid.
Trovärdiga resultat i en simulerad vattenmiljö erhölls ej, men indikerar att vattenmiljön
minskar bindningsstyrkan mellan HAp och magnesiumytan. I vakuum ökade
bindningsstyrkan mellan HAp och Mg(0001)-ytan i närvaron av en Na+-jon, medan
närvaron av en Cl– -jon minskade den. När Na+ och Cl– var närvarande i lika mängder
band HAp starkare till ytan än utan joner närvarande. Bindningsstyrkan mellan
flera lager av HAp och Mg(0001)-ytan visar att för många lager av HAp är mindre
gynnsamt energimässigt och att två lager av HAp verkar vara en optimal gräns.
Sammanfattningsvis är nästa steg att undersöka bindningsenergier i ett system som
använder vattenmolekyler istället för ett potentialfält och ifall flera lager av HAp följer
samma trend med ett utökat antal lager HAp
Electrification of Braking Systems on an Electric Regional Aircraft
No full textThe aviation industry is moving toward "more-electric" aircrafts to improve efficiency, reduce complexity, and lower overall system weight. Companies like Heart Aerospace are leading this transition by developing regional hybrid-electric aircraft, where traditionally hydraulic or mechanical systems are being replaced by electrically actuated alternatives to enhance sustainability and adaptivity to new power trains.
This thesis investigates the feasibility of replacing conventional centralized hydraulic braking systems with electrically actuated, brake-by-wire systems in regional turboprop aircrafts. Electrically actuated brakes offer the potential for weight reduction, improved modularity, and simplified system integration. A structured design approach was applied using the Double Diamond framework to generate, evaluate, and refine multiple braking system architectures in line with stringent aerospace requirements.
The most promising concepts were sized based on performance requirements, and their behavior was modeled and simulated under various runway conditions, including integration with anti-skid braking functionality. Additionally, an economic and energy impact assessment was conducted for implementing an electric taxiing motor, considering energy savings, motor and propeller efficiency, and taxi duration.
Results suggest that a federated electro-hydraulic system could provide the required braking performance while maintaining redundancy and enabling future integration of advanced controllers. The findings support the potential for transitioning to more-electric braking solutions in future regional aircrafts
Biophilic design in residential architecture; an exploration of indoor outdoor interfaces
No full textAutonomous Excavation Using Reinforcement Learning with Proximal Policy Optimization
No full textThis thesis presents a reinforcement learning based approach for grading, applied in
the Volvo excavator EC550E. The work was based around a simulation model of the
excavator which facilitated easy training of the algorithm. A hydraulic controller was
trained using proximal policy optimization. Together with the hydraulic controller,
a PID was implemented as a positional controller for a complete system capable of
performing grading tasks.
Training was conducted by testing different reward functions and parameter choices
to improve policy performance. The results showcases hyperparameter evaluation,
velocity tracking accuracy for the hydraulic controller as well as grading accuracy
of the complete system. The implemented solution had an accuracy of ± 4 cm during
grading. However, the hydraulic controller was not able to consistently follow
the target velocities in the cylinders, particularly for the bucket. In future works
the hydraulic controller needs to be retrained for better precision before being deployed
in a real machine. This thesis shows the potential and possibility of replacing
traditional control policies with an machine-learning driven approach