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spacecraft-guidance
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Spacecraft Planet Landing Control Based on Dual Quaternion
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor) ; Ghanbarpour Asl, Habib (Co-Advisor)
Abstract
In this study the problem of position and attitude control of a Spacecraft has been investigated under position and attitude constraints as well as uncertainties in mass, moments of inertia, thrust vector error, and external disturbances. The Lyapunov theory is utilized for deriving the appropriate controls. Two kinds of controls are derived in the first step. The first kind has been derived using direct Lyapunov method and the second by the use of back-stepping method. Obtained simulation results prove that the first control scheme is more suitable for a Spacecraft control, since it has less computational effort, convenient selection of control parameters, and especially it has less...
Spacecraft Control for Capturing Space Debris via Machine Learning Methods
, M.Sc. Thesis Sharif University of Technology ; Kiani, Maryam (Supervisor)
Abstract
The primary purpose of the present research is development and implementation of advanced state estimation and control techniques for space rendezvous and docking. To achieve this aim, the present study has first investigated the use of graph neural networks (GNNs) to filter out the noise of the sensor data in the state estimation process. The measurement package is consisted of a gyroscope, star trackers, and a GPS sensor providing inputs to the GNNs. The obtained results showed that the use of GNNs significantly improves the accuracy of the state estimation compared to traditional methods. In addition, the study has focused on developing advanced control techniques for spacecraft position...
Utilizing Gaussian Processes to Learn Dynamics of Unknown Torques Acting on a Spacecraft
, M.Sc. Thesis Sharif University of Technology ; Kiani, Maryam (Supervisor)
Abstract
Accurate and fast attitude estimation of a rigid body plays an essential role in the performance of a vehicle’s control system, especially aerospace vehicles. Ample works have been done to increase the accuracy and speed of the attitude estimation process, but all have been developed according to a model-based approach. This approach assumes that the torques acting on the body have a known dynamical model that is used for the attitude estimation. The purpose of the present research is to estimate the attitude via a model-free approach, i. e. dynamics of the torques acting on the body are no longer assumed to be known, and its learning is the next step. Thus, the problem formulation of this...