/library/oar/handle/123456789/27505 2025-11-05T10:39:08Z /library/oar/handle/123456789/28009 Title: Attitude control platform for pico satellites Abstract: Space interest is once again on the rise, with more contenders contemplating its scientific and commercial value. CubeSats have allowed smaller institutions, including universities, to join this effort through standardised structures that cut down development time and costs. The price point is further reduced by allowing the use of commercially available off-the-shelf (COTS) devices to perform beyond their limitations, in a harsh, radiating environment. At one-eighth the size of CubeSats, PocketQubes (PQs) are the way forward towards satellite miniaturisation. However, due to their more stringent constraints, their scientific applicability, has been till now, somewhat compromised. UoMBSat1, a PQ being developed by the University of Malta, aims to overcome this barrier by implementing, amongst others, a tri-axial, fully controllable attitude determination and control subsystem (ADCS). The payload, an impedance probe used for ionospheric measurements, dictates the choice of attitude-manipulating actuators by imposing the need for a magnetically clean environment, thereby the choice of reaction wheels and magnetorquers. With such limited resources, the question is whether such a complex design can be implemented within a PQ, while overcoming reliability issues. This thesis presents an architectural design approach coupled with a reliabilityemphasised philosophy on how to design compact electronic systems that guarantee reliability. This knowledge is then applied to the electronic design of an ADCS platform for UoMBSat1. Due to the unprecedented complexity of a PQ requiring a fully-active ADCS, whilst guaranteeing reliability through multiple layers of redundancy, the architectural implementation required a non-trivial, iterative, printed circuit board (PCB) design process, in an effort to maximise spatial efficiency. As an exercise in reliability engineering, the final design and architecture were subjected to a failure mode effect analysis (FMEA) study to validate the fail-safe mechanisms, identify functionality hindering failures and total failures. Description: B.ENG.(HONS) 2017-01-01T00:00:00Z /library/oar/handle/123456789/27563 Title: Characterisation of ultrasonic sensors for vehicle occupancy detection Abstract: Automotive companies are constantly evolving and adapting new technologies to offer better services and solutions. Methode Electronics is a leading company in this area, designing and manufacturing thousands of switches each year. In such an industry, a company like Methode must offer innovative products to keep up with the competition. This project serves as a proof of concept for such an innovative system. The proposed system is a seat belt reminder that uses one type of sensor, and can also function as a vehicle intrusion detector. This system is to be implemented in an overhead panel. The aim of this project is to correctly detect the occupant of the passenger seat, be it a person or an object, and implement an algorithm that would monitor the passenger seat area for any intrusions. Several different proximity sensors were compared to identify the best sensor for the application. Ultrasonic sensors were chosen and several ultrasonic sensors on the market were considered, ultimately choosing the HRLV-Maxsonar-EZ2. This sensor was tested to evaluate its detection zone for targets of different sizes, to analyse the error in the reported readings and to verify the sensor’s performance as the temperature varies. Two algorithms were implemented, one for vehicle intrusion detection and one for occupancy detection. Both algorithms were tested for different scenarios and under different conditions, to test their ability to correctly detect an occupant or intrusion. From the tests, it was concluded that the proposed system is able to correctly detect an occupant on the passenger seat and detect intrusion in the vehicle. There were some limitations of the system, and these were discussed in detail to find ways how to improve the system. Description: B.ENG.(HONS) 2017-01-01T00:00:00Z /library/oar/handle/123456789/27562 Title: Determination of dielectric properties of rocks for Ground Penetrating Radar (GPR) images Abstract: Ground Penetrating Radar is a method for analysing the sub-surface structure, and is currently being utilised to provide the accurate verification and location of possible buried hazards, such as mine shafts and voids, the identification of archaeological sites and the investigation of environmental conditions. Many of the cultural heritage sites in Malta were built using the Lower Globigerina Limestone. GPR can be used to provide data for analysis in the preservation and restoration of heritage sites in a non-invasive way. The GPR technique utilises electromagnetic radiation which results in various reflections. The GPR requires an initial guess of the dielectric properties of the target material/s for post-processing of the GPR images. Therefore, a study of the dielectric properties including the permittivity and the permeability values of the Lower Globigerina Limestone is required. This project, has sought to establish a foundation for further research on determining the dielectric properties of the Maltese rocks. Special attention was given to the Lower Globigerina limestone, samples of which were obtained from various boreholes around Malta. In order to achieve the dielectric values, a microwave measurement technique was chosen and measurements of the scattering parameters at a frequency range of 1.7 GHz to 2.6 GHz by the use of a Vector Network Analyzer (VNA) were taken. The sample was measured when it was fully saturated and fully dry. This frequency range was imposed by the GPR frequency operation at 2 GHz. After the rock sample was measured, the scattering parameters were processed through a conversion method to obtain the electromagnetic permittivity and permeability values. In order to achieve results with minimal uncertainty, a calibration procedure was conducted before each measurement session. This provided consistency and accuracy in the measurements. In this study, a set of values of the electromagnetic dielectric properties of the Lower Globigerina Limestone was established. Further testing was implemented to verify the permittivity value obtained for Lower Globigerina Limestone by the use of a GPR. Description: B.ENG.(HONS) 2017-01-01T00:00:00Z /library/oar/handle/123456789/27561 Title: A study of control laws for a quadrotor drone Abstract: This dissertation focused on the study of control laws for a quadrotor drone. It introduces the basic operation of a quadrotor and derives a mathematical model using Newton-Euler formalism. The basic architecture of a quadrotor system is also explained. A linear model was derived by introducing certain assumptions and was compared to the actual model. Hence, linear controllers were designed in continuous time for the roll, pitch, yaw and height of the quadrotor based on the linear model. These controllers were simulated thoroughly and converted to discrete time using two different techniques. Furthermore, the parameters of the quad rotor were obtained experimentally and mathematically. Finally, the controllers were implemented on the microcontroller and tested. Stands were used to test the attitude of the quadrotor. After some tuning, the attitude controllers worked as desired but improvements could be made. Description: B.ENG.(HONS) 2017-01-01T00:00:00Z