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Senast publicerade

Adaptive Lateral Control of Autonomous Trucks
(2026) Nair, Anirudh Vinod
Autonomous heavy vehicle control systems depend on a suite of parameters, both vehicular and environmental, and their performance is directly related to these parameter values. These parameters often include variables such as the total mass of the loaded vehicle, lateral and longitudinal tire cornering coefficients, wheelbase geometry, load distribution, etc. In theory, these parameters are often considered constant and known. However, in practice, this might not always be the case, especially in dynamic operating environments of a quarry or mine. Therefore, to ensure robust and reliable performance, the controller must be adaptive, updating itself online to continue operating efficiently. This thesis focuses on the investigation, development, and implementation of different types of adaptive lateral controllers for autonomous haulage trucks, whose parameters initially deviate from the true value and are subject to change during operation. The study focuses on evaluating both direct and indirect approaches to adaptive control. The direct adaptive controller uses a Lyapunov-based approach towards adaptation, meanwhile the indirect controller uses Kalman filter-based estimation methods to estimate unknown system parameters. Overall, the findings suggest that the indirect adaptive control strategies are more suitable for autonomous haulage applications. The integration of Kalman filterbased parameter estimation with model based controllers like LQR resulted in consistent performance and robustness, and better handling of system uncertainties compared to direct adaptive approaches.
Development and Optimization of Underwater Exhaust Outlets for Sailing Yachts
(2026) Fridh, Henrik; Hyltén, Lukas
Although sailing yachts primarily rely on wind for propulsion, engines are used for propulsion in unfavorable sailing conditions and maneuvering in the marina. On sailing yachts, exhaust gases are typically expelled through outlets positioned above the waterline. This can contribute to noise, vibration, odor and increased piping requirements, which may negatively affect onboard comfort, weight and space utilization. One solution to reduce these issues is to relocate the exhaust outlet underwater and closer to the engine. While underwater exhaust outlets are commonly used on motor yachts, their application on sailing yachts remains largely unexplored. This thesis investigates the development and optimization of an underwater exhaust outlet for sailing yachts using a structured product development approach supported by computational fluid dynamics. A representative 33 m sailing yacht hull was modeled and in total 30 exhaust outlet concepts were generated and evaluated with over 60 CFD simulations in OpenFOAM. The final concept, called the Quarter Bell-Mouth, consists of a tapered underwater outlet combined with an interceptor positioned near the outlet. The interceptor creates a low-pressure region that helps reduce back pressure and promotes a steadier exhaust gas flow. Simulation results indicate that the concept can expel exhaust gases underwater without negatively affecting the propeller or rudders while maintaining acceptable back pressure between approximately 8 and 13 knots at heel angles of ±5◦. However, oscillations at lower speeds indicate that a bypass exhaust is required below 8 knots. The results of this thesis show that underwater exhaust outlets are a promising design alternative for sailing yachts, with potential benefits in comfort, weight and space utilization. Future work should include validation on additional hulls, material and manufacturing studies and sea trials with a physical prototype.
Design av en kundanpassad display i wellpapp - från koncept till konstruktion
(2026) Nisén, Ylva; Yu, Emily
The purpose of this project is to explore the possibilities and limitations of corrugated cardboard and to examine how the material can be used to create an attractive display that showcases a brand. The aim is to develop and produce a display that is easy to assemble, easy to transport, and through its design promotes the hypothetical client Red Bull, a brand heavily associated with strength, endurance, and extreme sports. A preliminary study was undertaken to determine how corrugated cardboard displays are used today, how they are structurally built, and what material properties need to be considered. This was done through literature studies, observational studies, and unstructured interviews. An early ideation using brainwriting, brainstorming, sketches, and the KJ Method was conducted to establish a collaborative vision. Findings revealed that corrugated cardboard is a beneficial alternative from an environmental standpoint, as it has a high recycling rate, is lightweight, and can be designed compactly for transportation. However, corrugated fiberboard can be either rigid or bendable depending on the direction of its wave pattern. Compromises in the design are therefore often necessary to make the product more structurally stable and user-friendly. Computer-aided design, prototypes, and sketches were central to the process, enabling a clearer understanding of how two-dimensional drawings translate into physical products. The final product, a Formula 1- and Soapbox Race-inspired Point-of-Sale display, was fabricated to validate these findings. The result reveals that it is possible to design an attractive corrugated cardboard display that, through a strong visual expression, showcases and strengthens a brand’s identity.
Aerodynamisk design och vindtunnelstestning av vindkraftverk
(2026) Andersson, Clara; Karlsson, Elva; Skogh, Astrid; Sisask, Ralf-Kristjan; Åhlgren, Philip; Östling, Albin
Detta projekt syftade till att utveckla och experimentellt utvärdera rotorblad för ett modellskaligt vindkraftverk, med fokus på att förstå hur aerodynamiska parametrar påverkar prestanda vid låga Reynoldstal. Genom att kombinera numeriska simuleringar med vindtunnelstester undersöktes hur bladens geometri, vingprofil och vridning kunde optimeras för att maximera verkningsgraden hos små turbiner. Utvecklingsprocessen följde en iterativ metod där bladdesign, materialanalys, tillverkning och experimentell utvärdering genomfördes i flera steg. I designfasen användes programvaran QBlade för att simulera och optimera olika bladgeometrier baserade på befintliga vingprofiler, däribland serier som NACA och SG. Materialundersökningar genomfördes för att säkerställa tillräcklig styvhet och hållfasthet, vilket ledde till valet av kolfiberförstärkt PETG. De färdiga bladen tillverkades med 3D-skrivare och testades i Chalmers vindtunnel. De färdiga bladen testades i Chalmers vindtunnel där en maximal effektkoefficient på 41% uppmättes. Vidare utvärderades precisionen i de numeriska modellerna, där det konstaterades att simuleringsmetodernas förmåga att förutsäga effektkoefficienten varierade beroende på valda parametrar. Resultatet bidrar till en fördjupad förståelse för hur småskaliga rotorblad bör utformas för att prestera effektivt under de aerodynamiska begränsningarna som råder vid låga flödeshastigheter och utgör en grund för vidare utveckling av småskaliga vindturbiner.
Sensitivity of Proton Fixed-Target Experiments to Light Dark Matter
(2026) Ledell, Albin
Despite its remarkable success, the Standard Model of particle physics falls short of being a completely satisfactory theory. One prominent shortcoming is its inability to account for all the matter in the Universe, a discrepancy best explained by the presence of dark matter. Astrophysical and cosmological observations strongly indicate its existence, yet no non-gravitational interactions have been observed. The persistent null result may be attributed to dark matter being lighter than previously hypothesised, allowing it to have gone unnoticed in previous searches. This has driven growing interest in accelerator-based experiments, particularly fixed-target experiments. In this thesis, light dark matter (LDM) is investigated at proton fixed-target experiments, focusing on a minimal dark sector model with complex scalar dark matter and a dark vector mediator. Using the MadDump plugin to the MadGraph5_aMC@NLO framework, the sensitivity of the primary dark matter production channels is studied for the forthcoming experiments SHiP and DUNE ND, as well as the operational NOνA ND. In particular, the newly approved SHiP design and different operational modes of DUNE ND are considered. Additionally, a new secondary production channel in the form of photoproduced vector meson decay is considered, with the analysis performed largely analytically. This channel has recently been shown to enhance sensitivity in electron beam experiments. Here, no such enhancement is observed. The origin of this difference is not yet fully understood, with possible explanations including an insufficient flux of high-energy photons in the processes considered and a potential overestimation of dark photon production in the primary channel.