Browsing by Author "Serfontein, Gideon"

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    Development and verification of an electro-mechanical docking mechanism for flight
    (Stellenbosch : Stellenbosch University, 2024-03) Serfontein, Gideon; Jordaan, Willem; Visagie, Lourens; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: This thesis focused on the development of a docking system for CubeSats with the aim of using it in a demonstration mission named DockSat. The system includes a docking adapter and a mechanism to lock the satellites together, a pose estimation system employing both LED fiducial markers and a camera, electromagnetic coils to allow control of relative position and the control algorithms needed. This work, particularly the pose estimation system and docking adapter were based on work done by Robert Waller for his master’s. The different parts of the system were designed with one another in mind. This included the mechanical design that was made to work with the pose estimation system as well as the coil. As a part of this integration, a PCB was designed to act as the back-pane of the docking adapter that could hold the electronics for the electromagnetic coil as well as the LEDs used for the pose estimation. Each part of the system was developed and tested separately. Starting with the docking adapter, the mechanism was updated to make it more robust, manufacturable and lockable. This was tested with a series of tests to test its misalignment robustness and locking force. Secondly, the pose estimation system was integrated into the docking adapter. Tests were conducted to measure its accuracy and it was found to be suitable. Thirdly, magnetic coils were designed to be integrated into the docking adapters. This was done using simplified models of electromagnets as well as simulations. Afterwards the coils’ strength and force were tested. Using the results from previous tests, simulations were done in both 2 and 3 dimensions. PID controllers were designed to control the electromagnets and the reaction wheels. The control scheme was found to be effective to bring the two satellites together from rest to dock. Thus a complete system for docking was formulated. The test results show that the system is suitable for the DockSat mission.