https://www.um.edu.mt/library/oar/handle/123456789/129100 2026-09-01T13:16:32Z https://www.um.edu.mt/library/oar/handle/123456789/148634 Title: Development of a force sensitive prosthetic finger Abstract: Many modern prosthetic hands lack the ability to sense applied forces and those that do, often cannot accurately detect the location at which the force is acting, limiting the user’s feedback and dexterity. This project aims to create a practical force sensor for a prosthetic finger. The design consists of four strain gauges mounted on an internal beam structure enabling accurate detection of both force magnitude and location. The sensor was developed with careful attention to mechanical structure, signal processing and physical constraints for effective operation. A prototype sensor was fabricated, assembled and thoroughly tested to evaluate its performance. The results obtained from testing were critically analysed, followed by an extensive discussion about the sensor’s performance over different force and location ranges. Across all testing points, the median force uncertainty was ±2.36% and the median location uncertainty was ±1.87 mm. Overall, this project contributes to the advancement of tactile sensing in prosthetic fingers by demonstrating a compact, robust, and feasible sensor design capable of force and position detection. This supports the development of more functional and user-appropriate prosthetic hands with the potential to improve the quality of life of amputees. Description: B.Eng. (Hons)(Melit.) 2025-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/148632 Title: Vertical dynamics characterisation of formula student suspension Abstract: Surfaces of motorsport race tracks are not perfectly smooth and lead to driver discomfort and variation in the tyre vertical force that reduce the performance of the driver and the vehicle. The aims of the project are to quantify the effect of several parameters that influence the vertical behaviour of a formula student vehicle such as stiffness and damping using numerical simulations and experimental tests. A numerical model is implemented in MATLAB/Simulink allowing the behaviour of a quarter car vertical dynamics model to be simulated on any road profile defined by the user. The vertical tyre stiffness and shock absorber damping are modelled using empirical fits based on experimental data from a dedicated tyre testing rig and a suspension damper dyno. Three road profiles with different roughnesses are generated in accordance to ISO 8608 and tested using various vehicle speeds, tyre pressures, shock absorber damping settings, spring stiffnesses, sprung masses and unsprung masses. From a review of literature, it was found that the tyre damping is expected to be significantly higher for a non-rolling tyre compared to a rolling tyre. Additionally, tyre damping is observed to be highly nonlinear and difficult to quantify and model. Therefore, a common approach in literature is to assume negligible tyre damping. However, the validity of the assumption for the required results is analysed throughout the project. A multi-purpose experimental test rig is designed and constructed for the project. Tests to estimate the tyre damping of a non-rolling tyre are conducted using a free vibration logarithmic decrement method and a forced vibration method based on a gradient-based optimisation using the numerical model. The tyre damping is estimated and observed to be deformation, frequency and/or velocity dependent. The uncertainty related to Coloumb friction in the linear bearings of the experimental test rig is estimated and found to have a significant impact on the results at low velocities. Tests are conducted on the experimental test rig to validate the numerical quarter car model. The correlation of the numerical model to the experimental test rig is considered satisfactory although Coloumb friction in the shock absorber is found to have a significant impact at low damping settings and low damper speeds indicating that the empirical fit used should be adjusted to capture the stick-to-slip transition near zero velocity. The optimal shock absorber valve settings for driver comfort and tyre load variation are found and the effect of tyre damping on the results is considered negligible. The sensitivity of driver comfort and tyre road holding to tyre pressure, spring stiffness, sprung mass and unsprung mass is found. However, the non-rolling tyre damping value used significantly impacts the results indicating that a negligible tyre damping assumption is not adequate for sensitivity analysis. Further work is required to estimate the tyre damping for a rolling tyre to achieve representative sensitivities. Description: B.Eng. (Hons)(Melit.) 2025-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/147102 Title: The PQ8 architecture : deploying picosatellite constellations from a single launch Abstract: Over the past decade, demand for nano- and pico-class satellites has surged, driving up costs and competition for launch opportunities. CubeSat launches, once easily accessible, have become prohibitively expensive for small institutions, especially when considering constellation deployment. Although the PocketQube standard offers a lower cost alternative, its adoption has been limited and its cost benefits modest, primarily due to launch integration limitations, debris mitigation and trackability concerns. To address these challenges, this work proposes the PQ8 Architecture: a novel deployment model for pico-scale satellite constellations that reduces launch costs by up to 87 %, simplifies integration, and enables the simultaneous deployment of multiple satellites. The research is divided into three key components. First, the structural design is developed to accommodate eight PocketQube-sized satellites within a 1U CubeSat frame, while remaining scalable. The design is evaluated using finite element analysis and mechanical testing, including modal analysis, vibration, shock, and static load tests, all in accordance with ECSS launch qualification guidelines.. Second, constellation dispersal is addressed through tailored differential drag control algorithms. This approach calculates separation velocities and timing to achieve in-plane phasing, accounting for the operational parameters introduced by the PQ8 form factor. Two case studies with orbital simulations validate the method’s effectiveness and scalability. Third, a novel disengagement mechanism is presented, in which magnetorquer coils are reconfigured to act as synchronized electromagnetic actuators. The circuitry is validated through simulation and bench-top testing, and actuator forces are confirmed via finite element analysis. Overall separation dynamics are then demonstrated using a pendulum testbed to emulate near-free-body translational and rotational disengagement behaviour. Together, these contributions, structural innovation, coordinated dispersal, and integrated separation, form a robust and cost-effective platform for small-satellite constellations. The PQ8 Architecture significantly lowers the barriers to entry and enables missions that would otherwise be financially or logistically infeasible. Description: Ph.D.(Melit.) 2025-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/145633 Title: Surface engineering of wire arc additively manufactured AZ80 magnesium alloy Abstract: This study investigates the surface engineering of wire arc additively manufactured (WAAM) AZ80 magnesium alloy, focusing on the combined effects of process parameters, heat treatment, and shot peening on its microstructure and mechanical performance. WAAM AZ80 was produced using two processing conditions: one producing materials with higher defect content (P1) and the other yielding a densified, near-defect-free condition (P2). Specimens were extracted along both parallel and perpendicular to the build direction to assess anisotropy, and benchmarked against wrought EN AW-6082 aluminium alloy in the T6 condition. The findings showed that process-induced defects strongly influenced tensile anisotropy, whereas T6 heat treatment improved ductility, hardness, and tensile strength, reducing orientation-dependent disparity and bringing the mechanical properties closer to EN AW-6082. Compression strength exhibited limited sensitivity to defect content. Shot peening further enhanced the surface integrity by inducing grain refinement, work hardening, and CRS, though at the expense of increased roughness. The surface hardness increased by up to 45% in WAAM AZ80 and by 14% in EN AW-6082, while peak CRS reached ~110 MPa in WAAM AZ80 and ~280 MPa in EN AW-6082. Fatigue life improvements were most pronounced in WAAM AZ80, with shot peening extending life by up to 160%, depending on the printing and associated defect orientation, and enabling run-outs beyond 106 cycles in P2 samples through delayed crack initiation and reduced surface-connected porosity. Although EN AW-6082 retained higher absolute fatigue strength, the results demonstrate that refined process control, T6 heat treatment, and shot peening can collectively transform WAAM AZ80 into a competitive lightweight alternative for aerospace and satellite applications, particularly under cyclic loading conditions. Attempts to improve electrical performance through gold coatings highlighted the challenges of plating reactive magnesium alloys. While electroplating failed to achieve uniform coverage, sputtered coating produced more continuous films but did not significantly enhance conductivity, underscoring the need for tailored pretreatments and interlayers for functional integration. Description: M.Sc.(Melit.) 2025-01-01T00:00:00Z