https://www.um.edu.mt/library/oar/handle/123456789/9973 2026-07-20T23:45:22Z https://www.um.edu.mt/library/oar/handle/123456789/148128 Title: Development of an analytical framework for robot-inclusive homes, and of an autonomous assistive robot Abstract: Robotic assistance in domestic environments is gaining importance for supporting older adults and people with impairments. Many domestic robots depend on complex algorithms and high computational power, which raises cost and makes integration into ordinary homes difficult. At the same time, most homes are not arranged to help robots see, reach, or move well. This research addresses that mismatch by treating the person, the robot, and the home as one measurable system, and by showing that a simple robot can deliver useful assistance in a space designed to support it. The research develops a Robot-Inclusive Space framework that formalises design and evaluation across four linked measures. Human Impairment Index evaluation and task demand set an explicit upper bound on robot capability through the Robot Complexity Index. The Robot Inclusive Space Index quantifies how layout choices support observability, accessibility, and manipulability. The Space Convertibility Index estimates the effort to reach a target layout under practical limits of cost, effort, and time. The study follows a structured RIS workflow: impairments are evaluated and translated into remaining capacities, mapped to task demands, and used to identify the minimum robot features required. RIS home modifications are then defined to support both robot operation and human needs, and their feasibility is assessed in terms of cost, effort, and time. Using a teleoperated baseline, MARIS-I, the study motivates MARISII, a semi-autonomous platform sized for small homes that combines lightweight mapping, marker-aided localisation, goal-biased curvature-bounded planning, and suitable sensor placement with simple task stations consistent with the framework. Validation in physical layouts designed according to Robot-Inclusive Space principles uses consistent hardware and repeatable trials to assess reliability and efficiency. Clear sightlines, uncluttered paths, structured object placement, and marker cues keep mapping and planning lightweight and support pick and place within defined zones. Across experiments, RIS-guided design reduces planning latency, turn counts, and processor load while maintaining path quality, enabling MARIS-II to operate more reliably with lower computation. Overall, the results show that measurable improvements in observability, accessibility and manipulability reduce the need for robot-side complexity and help identify the smallest set of feasible home changes, within realistic cost, effort and time limits, for compact single-floor homes. Description: Ph.D.(Melit.) 2026-01-01T00:00:00Z 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/123456789/146877 Title: Developing an immersive learning environment for engineering education and re-skilling, using metaverse technologies Abstract: Industry 4.0 and 5.0 demand engineers with higher-order competencies, that can be difficult to cultivate through traditional lecture-based instruction alone. Immersive technologies offer potential solutions, yet existing research has focused on single-user applications, leaving collaborative metaverse affordances relatively underexplored. The absence of structured frameworks for developing metaverse educational environments further hinders adoption. This thesis investigates metaverse-based learning environments for educational outcomes within manufacturing. The research addresses three gaps: the lack of structured frameworks, the limited exploration of how immersive technologies can support learning of complex interdependent concepts, and the underutilisation of multi-user collaborative affordances. The MITE (Metaverse Immersive Training Environment) framework was developed, integrating Design Thinking with educational models including TPACK, Constructive Alignment, and the 5E instructional model. The framework was validated through a proof-of-concept prototype targeting Quality Assurance and Process Layout Optimisation. These topics exemplify the interconnected nature of modern manufacturing yet are typically taught in isolation. The prototype integrates both disciplines within a collaborative virtual manufacturing environment, enabling realtime collaboration with complex scenarios. A comparative evaluation study compared Learning Outcomes (LOs) between those receiving the metaverse experience and traditional instruction alone. Results indicated that the metaverse group outperformed the traditional group across all measures: mean knowledge scores of 44.69 compared to 41.04 out of 60, greater confidence gains, and completion rates of 84% compared to 63%. The effect size of 0.44 exceeds the average effect of educational interventions, representing a practically significant improvement in LOs and engagement. This research contributes a replicable framework for developing metaverse-based learning environments, empirical evidence supporting immersive collaborative learning for complex engineering topics, and demonstrates the value of multi-user metaverse over single-user VR in developing teamwork and systems thinking competencies demanded by Industry 4.0 and 5.0. Description: M.Sc.(Melit.) 2026-01-01T00:00:00Z 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