Design, Fabrication and Modelling of Three Axis Floating Satellite Simulator

Abstract: The Floating Satellite (FloatSat) system project which has been developed at the ‘Department of Aerospace Information Technology - University of Würzburg’ is used to test, develop and implement various attitude control algorithms and strategies for small satellites [1]. The FloatSat project is designed to operate on a Frictionless air bearing surface that works with compressed air flowing distributed on a hemisphere. This hemisphere is used to replicate the space environment required for a satellite to perform its attitude control, solar panel deployment and payload mission, the FloatSat basically consist of 1 axis control and stabilization with reaction wheel. Taking FloatSat to the next level, the aim of the Thesis is to Design, Fabricate and Model a three-axis controllable FloatSat that can be contained in a Sphere for free rotation and movement. The best feature of FloatSat is that they are plug & play, easily accessible and compact size; retaining all these features in the design and extending the functionality of the product proves to be challenging. Furthermore, in the thesis it will be explained in detail about the various design consideration and selection of most feasible method on producing the final product. After the preliminary research for the design characteristics it was clear that the new FloatSat will be equipped with a controllable center of gravity mechanism that will provide balancing in any desired orientation. To obtain this feature three controllable moving masses are to be used in each axis of reaction wheel position. With Three reaction wheels and three moving masses to be equipped in the FloatSat the design challenges were high as considering the Sphere diameter is only 198mm. The various successful 3 axis satellite simulators are either huge or they are constrained in any one of the axis where it is positioned. On doing literature research it became clear that the sphere configuration with the given size has never been documented with promising results. It makes this thesis work to be first of its kind to perform 3 Axis FloatSat stabilization in a sphere of 198mm diameter. The FloatSat components include microcontroller STM32F4, Wi-Fi module for communication, three reaction wheel motors, three axial moving mass motor, Lithium Polymer batteries and motor controllers.