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Senast publicerade

Design och konstruktion av en 3D-scanner för små objekt
(2026) Damberg, Remus
Detta arbete beskriver konstruktionen av ett skanningssystem för små objekt, utvecklat på uppdrag av Wiretronic AB. Systemet är ämnat att komplettera Wiretronic’s existerande lösningar genom att erbjuda högdetaljerad fotografering av små objekt i storleksordningen 0,5-20mm i syfte att användas för 3D-modellering och träning av AI-modeller. Systemet består av en kvartcirkelformad båge med fyra kameramoduler, ett stegmotordrivet rotationsbord, LED-belysning med manuellt justerbar ljusstyrka och färgtemperatur, samt en Raspberry Pi 4B som beräkningsenhet. Tre avbildningslösningar utvärderades. Raspberry Pi HQ-kameran med teleobjektiv valdes då den optiska förstorningen möjliggjorde effektivt utnyttjande av sensorns upplösning och gav ett tillräckligt skärpedjup för de aktuella objekten. Valet av motorsystem gjordes på teoretisk grund, där stegmotorns positioneringsnoggrannhet utan behov av extern återkoppling bedömdes vara det mest lämpade alternativet. Detta bekräftades vid praktisk testning, där stegmotorn uppvisade mycket god noggrannhet och repeterbarhet. LED-strips med hög färgåtergivning och justerbar färgtemperatur valdes som belysningslösning då dessa gav ett jämnare ljus med färre skuggproblem jämfört med punktformade LED-moduler. Det färdiga systemet fungerar väl och uppfyller de ställda kraven. Identifierade förbättringsmöjligheter inkluderar en mer precis tillverkningsmetod för de mekaniska delarna, då 3D-printing med kommersiell utrustning introducerar geometriska toleransavvikelser som ger en viss gungning i rotationsbordet som blir märkbar först vid inzoomning på objektet. Fast montering av kameramodulerna via deras kretskortsfästen skulle ge en mer robust långsiktig lösning jämfört med det klämbaserade monteringssystemet. Belysningsstyrningen som i nuvarande utförande sker manuellt via potentiometrar skulle med fördel kunna regleras via Raspberry Pi för smidigare kontroll och reproducerbarhet.
Image Processing Framework for Accuracy Measurements in Real-Time Endovascular Simulation
(2026) Franzén, Adam; Swanmark, Linnéa
Training surgeons to navigate catheters and guidewires through blood vessels is challenging, and simulators are increasingly used to practice these procedures safely. However, no standard method currently exists to objectively measure how realistically a simulator reproduces the behavior of real surgical instruments. This thesis presents an image-based framework for the quantitative comparison of physical and simulated catheter configurations, combining camera-based image acquisition, centerline extraction, geometric alignment, and shape comparison metrics. Physical experiments were performed by imaging catheters and guidewires both on flat surfaces and inside a vascular phantom (Physical SIM). The same instrument configurations were then reproduced in the Mentice simulator (VIST), allowing a direct comparison between the physical and virtual setups. The framework was further extended with an automated optimization module that searches for simulator stiffness parameters that best reproduce the observed physical catheter behavior using Bayesian optimization. Validation experiments demonstrated high accuracy in catheter length estimation, achieving a mean absolute error of 0.117 cm and a coefficient of determination exceeding R2 > 0.99. It also remained consistent regardless of the catheter shape. The alignment procedure showed that the extracted centerlines converge to a close geometric correspondence after registration. Optimization experiments further showed that simulator stiffness parameters could be tuned to reproduce physical catheter configurations with high geometric similarity, although discrepancies remained for certain catheter-guidewire combinations. A direct comparison between the physical and virtual environments was additionally limited by fundamental differences in anatomy representation. The results demonstrate that the proposed framework enables quantitative and repeatable evaluation of endovascular simulator realism. Among the evaluated metrics, RMS error and curvature analysis were found to be the most informative: RMS error for localizing spatial deviations along the catheter shaft, and curvature analysis for capturing mechanical differences in instrument bending behavior. The framework provides a foundation for future validation and calibration of catheter mechanics in anatomically realistic simulation environments.
Immersiva upplevelser som väcker intresse -Utveckling av en immersiv installation som lockar unga vuxna till GöteborgsOperan
(2026) Dahlin Griph, Otto; Levinsohn, Douglas
This thesis investigates how immersive installations can be used to spark interest for the Gothenburg Opera among young adults aged 18–35. The study was conducted using a user-centered and iterative design process that included a preliminary study, user interviews, concept generation, protype development, and user testing. Qualitative methods like affinity diagrams, observations, and group interviews, were used to identify key factors influencing engagement and immersion. The findings indicate that social interaction is the most significant factor contributing to the impact of the experience, while emotional engagement and coherent multisensory design also play important roles. Two final prototypes, a narrative driven puzzle installation and a social competitive shadow play experience demonstrate that immersive installations have the potential to increase young adults’ interest in opera and spark curiosity about the Gothenburg Opera´s activities. However, this potential depends on a clear connection between the installation and the opera´s content, as well as an accessible and intuitive user experience.
Micromechanical modeling of fracture in high-pressure die cast aluminum
(2026) Abel, William; Kullberg, Valdemar
High-pressure die cast aluminum is being incorporated into the production of electric vehicles in order to increase vehicle efficiency and reduce manufacturing costs. The process is known as Mega Casting and can produce large scale components with complex geometry in one process, drastically reducing the amount of welds and joints. Due to the process, the aluminum components possess a complex microstructure with different phases and porosity, which makes the mechanical properties difficult to predict. Today, there is a lack of Finite Element (FE) and material models that can capture these microstructural defects on a component scale. Throughout the project, a method for generation of three-phase microstructure models based on Computer Tomography (CT) scanning and Scanning Electron Microscope (SEM) images is developed. Numerical studies on mesh design, time integration and boundary conditions are performed with the intention to optimize computational costs while maintaining accuracy. Furthermore, the variation in mechanical properties depending on morphology is studied by simulating a range of different microstructures subjected to different load cases. The results show that it is possible to generate three-phase microstructures that represent the eutectic silicon region in HPDC-aluminum components. The choices of the numerical model and modeling have impact on computational efficiency and accuracy. Furthermore, it is possible to vary the internal morphology in the model in order to obtain mechanical response data for a wide range of microstructures.
Impact of Converter Size Asymmetry on Power Transfer in Railway Power Systems
(2026) Alrup, Filip; Hidevik, William
This thesis investigated the impact of converter station capacity asymmetry on power transfer for different system impedances. The scope of this thesis was to investigate the significance of the adjustable static converter parameters, in order to minimize active power losses in the railway power system. This thesis only considers the static frequency converter (SFC), and since an SFC solely consists of power electronics and is modeled to mimic the behaviors of a rotary frequency converter (RFC) through software, the parameters are adjustable. This means that it was possible to adjust the quadrature reactances for instance, which would not be possible if the RFC were modeled. The Y-bus matrices and the load profiles were made in Matlab whilst the optimization and load flow models were constructed in the General Algebraic Modeling System (GAMS), which was used to optimize the system with the objective function to minimize active power losses. Various cases were simulated where the converter parameters were optimized for both the autotransformer (AT) - and booster transformer (BT)-systems to understand the system for representative cases. The models were used for studying realistic cases as well as cases with large asymmetry in terms of power capacity and different load locations between substations. This was done to shed further light regarding the philosophy of local production, whether it should be prioritized or not. The results show, for both the AT- and BT-system, that if the load is located in the middle of the line, it is optimal for the substations to share the load as evenly as possible. If the load is located closer to one substation than the other, then the system should prioritize local production regardless of the substation capacities. If there is a large asymmetry between the substations, in terms of installed total power capacity, it is more optimal to control the load-sharing with the no-load angle than other parameters. Optimization of the no-load angle reduced power losses for all cases, particularly when the substations had highly asymmetric power capacities. However, it was shown that the no-load voltage should always be kept as high as possible. The results also show that the quadrature reactances should be as low as possible in order to minimize losses, this is possible since the SFC quadrature reactances can be set in the software controlling the power electronics. In regards to the active- and reactive power droops, it was shown that with optimization they were not able to reduce the losses significantly. In contrast, it was shown and discussed that the active power droop, when solely optimized, was able to reduce the voltage drops and decrease the overall voltage variations. However, during the full optimized cases, the droop factor did not give such significant change since it was probably de-prioritized. It was also discussed that the reactive power droop got very small for the BT-system when the no-load voltage also were optimized, which probably is a result of the high no-load voltage and limited load model. In order to reach clarification regarding the droop constants, a load model with higher complexity would be needed.