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Full-Text Articles in Aerospace Engineering
Sliding Mode Control With Chattering Reduction, Suryamshu Ramesh
Sliding Mode Control With Chattering Reduction, Suryamshu Ramesh
Doctoral Dissertations and Master's Theses
Sliding Mode Control is a powerful nonlinear control methodology that can handle parametric uncertainties and external disturbances. However, the discontinuous and high-frequency switching nature of the control law introduces the chattering phenomenon, which leads to potential actuator degradation, alterations to the desired response characteristics and, sometimes, instability during control implementation. The main objective of this thesis is to study Sliding Mode Control with chattering reduction. The Sliding Mode Control law involves an equivalent control component and a discontinuous control component. A disturbance estimation is performed based on Lyapunov analysis and adaptive control techniques and then included in the control law …
Dynamic Analysis Of Cubesat Impact On Lunar Surface, Dalton C. Korczyk
Dynamic Analysis Of Cubesat Impact On Lunar Surface, Dalton C. Korczyk
Doctoral Dissertations and Master's Theses
EagleCam is a pico-satellite (CubeSat) with dimensions of 100 x 100 x 150 mm3 that is going to the moon as a payload of the Intuitive Machines Nova-C lunar lander. The CubeSat’s purpose is to record the lunar landing from a 3rd person view. Unlike other CubeSats, EagleCam is designed to impact the lunar surface and there is no history to build off of. Specifically, EagleCam will need to survive a 30 m drop onto the lunar surface with all internal components fully operational post impact. This thesis is focused on the analytical, numerical, and experimental methods for determining the …
Relative Attitude Dynamics And Control Of Spacecraft Using Electrostatic Torque, John Galjanic
Relative Attitude Dynamics And Control Of Spacecraft Using Electrostatic Torque, John Galjanic
Doctoral Dissertations and Master's Theses
Recent years have seen an increased interest in spacecraft formation flying, with many applications requiring that the members of these formations maintain specific relative attitude configurations. One low-cost method that has been considered to accomplish this is the use of electrostatic torques, which are generated by charging the surfaces of involved spacecraft to allow interaction without physical contact. The research presented in this thesis analyzes a pair of cylindrical-bodied spacecraft operating in deep space. Specifically, the suitability of using electrostatic torques as an actuator to synchronize the two spacecraft's attitude responses is under consideration. The study considers a simplified case, …
Development Of A Research Spacecraft Test-Bed With Implementation Of Control Laws To Compensate Undesired Dynamics, Yomary Angélica Betancur Vesga
Development Of A Research Spacecraft Test-Bed With Implementation Of Control Laws To Compensate Undesired Dynamics, Yomary Angélica Betancur Vesga
Doctoral Dissertations and Master's Theses
The development of research spacecraft systems has a significant impact on the preparation and simulation of future space missions. Hardware, software and operation procedures can be adequately tested, validated and verified before they are deployed for the actual mission. In this thesis, a spacecraft vehicle test-bed named Extreme Access System (EASY) was developed. EASY aims at supporting validation and verification of guidance, navigation and control algorithms. Description of EASY spacecraft systems, sub-systems and integration is presented in this thesis along with an analysis of results from numerical simulation and actual implementation of control laws. An attitude control architecture based on …
Optimal Non-Coplanar Launch To Quick Rendezvous, Gregory B. Sears
Optimal Non-Coplanar Launch To Quick Rendezvous, Gregory B. Sears
Theses and Dissertations
The purpose of this study was to determine the feasibility of launching a Delta Clipper-like vehicle on an optimal, non-coplanar trajectory to rendezvous with an earth orbiting object in one orbit or less. The focus of the research was to determine what such a trajectory would look like, and to determine the cost, in payload mass, of flying such a trajectory. A model for the ascent trajectory was developed using the dynamics equations of motion, an atmosphere model, and an aerodynamic model for the DC-Y concept vehicle. A boundary value problem was posed and solved for a coplanar rendezvous. The …