Browsing by Author "Felicetti, Leonard"

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    A review of state-of-the-art 6D pose estimation and its applications in space operations
    (CEAS, 2024-06-11) Singh, Siddharth; Shin, Hyo-sang; Tsourdos, Antonios; Felicetti, Leonard
    Increase in autonomous systems now requires for these systems to work in close proximity of other objects in their environments, with many tasks that need to be done on environment objects for eg., assembly, transportation, rendezvous, docking, or to avoid them like collision detections/avoidance, path planning etc. In this literature review we discuss machine learning based algorithms that solve the first step of vision-based autonomous systems i.e., vision based pose estimation. This paper presents a critical review in advancements of 6D pose estimation using both 2D and 3D input data, and compare how they deal with the challenges shared by the computer-vision based localisation problem. We also look over algorithms with their applications in space based tasks like in-orbit docking, rendezvous and the challenges that come with space-vision applications. To conclude the review we also highlight niche problems and possible avenues for future research.
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    On-orbit servicing strategies for large constellations via hybrid dynamic programming
    (CEAS, 2024-06-11) Lhuillier, Ignacio Betti; Bellome, Andrea; Felicetti, Leonard
    The increasing number of mega-constellations inLEOis not only increasing the number of satellites in orbit but potentially might trigger an increment in the amount of space debris. On-orbit servicing is seen as a viable solution to minimize the number of launches needed to maintain these constellations and keep the debris levels low. This paper focuses on trajectory planning for On-Orbit Servicing (OOS) by presenting a novel methodology based on dynamic programming hybridized with deterministic tree search strategies. This is used to schedule the best path for spacecraft to visit satellites that need servicing (such as repair, refueling or repositioning). This methodology is then used to conduct Monte Carlo simulations to study how the main characteristics of the spacecraft affect the performance of the servicing operation. The presented study aims to find the optimal number of servicers needed, the ^V required to perform the operations, and the time of flight between satellites.
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    Robust sliding mode controller design for orbital payload deploying spacecraft
    (CEAS, 2024-06-11) Platanitis, Konstantinos; Felicetti, Leonard; Upadhyay, Saurabh; Capicchiano, Leonardo
    This work demonstrates the feasibility of usage of a sliding mode controller in the case of orbital payload deployers. The proposed control law suggested herein allows for disturbance rejection during the payload deployment phase, as well as provide a basis for angular rate tracking purposes. The stability of the control law is determined by Lyapunov theory, and realistic spacecraft simulations have been created to verify the robustness in the presence of disturbances as well as the general tracking capabilities.