Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"Spacecraft Dynamics"”.
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Learning-Based Methods for Spacecraft Dynamics Modeling, Filtering, and Predictive Control
Spacecraft motion under model uncertainty arises in many on-orbit assembly, servicing, and assistance scenarios, including tasks requiring manipulation of unknown grappled objects. Traditionally, adaptive model-based control approaches have relied on an analytical dynamics model with a set of …
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CubeSat attitude control using micronewton electrospray thruster actuation
… MIT Space Propulsion Laboratory. A high fidelity spacecraft dynamics simulation was constructed for analysis of the performance of the ADCS system. Attitude determination was tested with an engineering model of a 1U CubeSat, and the entire ADCS system was tested in simulation. Results of these …
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Control of spacecraft in proximity orbits
Formation flying of spacecraft and autonomous rendezvous and docking of spacecraft are two missions in which satellites operate in close proximity and their relative trajectories are critically important. Both classes of missions rely on accurate dynamics models for fuel minimization and observance …
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Adaptive-Optimal Control of Spacecraft near Asteroids
<p>Spacecraft dynamics and control in the vicinity of an asteroid is a challenging and exciting problem. Currently, trajectory tracking near asteroid requires extensive knowledge about the asteroid and constant human intervention to successfully plan and execute proximity operation. This work aims …
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Centimeter-Scale Spacecraft: Design, Fabrication, And Deployment
… Many of these components are suitable for use in spacecraft. Their availability has led to the ongoing revolution in small satellites, most visibly exemplified by the CubeSat standard. This study seeks to push these trends toward their ultimate extreme: a satellite-on-a-chip. The ability to mass …
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Variable structure and singular perturbation control of elastic dynamical systems
… output is judiciously chosen such that the zero dynamics are stable or almost stable. For the control of the end point, two kinds of parameterizations of end effector position are considered. A variable structure control (VSC) law is derived for the end point trajectory control of each chosen …
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Towards Autonomy: Leveraging Nonlinearity In Predictive And Convex Optimization For Space Vehicle Guidance And Control
… which should be capable of handling complex dynamics, real-world constraints, and limited computational resources. While model predictive control (MPC) and sequential convex programming (SCP) techniques offer promising capabilities, their performance may be restricted when underlying dynamics …
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Adaptive Control Combined with Integral Concurrent Learning for Trajectory Tracking Near Asteroids
… Unlike motion around large celestial bodies, spacecraft dynamics near small, rotating asteroids are dominated by weak, highly irregular gravity fields. While full characterization of an asteroid’s shape enables high-fidelity gravitational modeling, such information is typically unavailable in …
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Dynamics and Control of a Tensegrity System in Low-Earth Orbit
… structure in orbit around the Earth. As a spacecraft's orbit is moved further away from the Earth, the strength of the Earth's gravity field lessens. Ideally, such a flexible structure would be placed far enough away from the Earth so that the gravity field would have too weak an impact on …
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Low thrust augmented periodic orbits in the two- and three-body problems
… propulsion can add considerable utility to spacecraft dynamics by enabling rich new families of thrust augmented orbits. With the aim of enabling such orbits for small, low-cost spacecraft with limited on-board sensing, new families of non-Keplerian orbits are generated in the …
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The dynamics and control of the CubeSail mission—A solar sailing demonstration
… of the solar sail film into two CubeSat-class spacecraft, through on-orbit deployment dynamics, attitude control of large and flexible space structure, and predictions of performance and orbital maneuvering capability.
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Orbital Maneuvers and Interplanetary Trajectory Design via Reinforcement Learning
… to the design and optimization of low-thrust spacecraft trajectories, with an emphasis on autonomy, adaptability, and robustness in the presence of system uncertainties and unmodeled perturbations. Classical approaches to low-thrust trajectory design are predominantly grounded in optimal …
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Spacecraft Attitude Tracking Control
The problem of reorienting a spacecraft to acquire a moving target is investigated. The spacecraft is modeled as a rigid body with N axisymmetric wheels controlled by axial torques, and the kinematics are represented by Modified Rodriques Parameters. The trajectory, denoted the reference …
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Natural and perturbed dynamics about Trojan bodies
This thesis analyses the dynamics of a massless spacecraft (or point mass) around an inhomogeneous Trojan body in a system composed of three primaries lying on a plane at the vertexes of an equilateral triangle, with their mutual positions fixed over the course of the motion. This configuration …
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Constant Orbital Momentum Equilibrium Trajectories of a Gyrostat-Satellite
This dissertation investigates attitude transition maneuvers of a gyrosat-satellite between relative equilibria. The primary challenge in transitioning between relative equilibria is the proper adjustment of the system angular momentum so that upon completing the transition maneuver the …
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Adaptive Control of Thrusters to Account for Deficiencies in Actuator Effectiveness and Model Uncertainties
… and adaptive control laws for an over-actuated spacecraft system with 3 degrees of freedom (DoF) to mitigate the effects of actuator deficiencies and system uncertainties. Additionally, the nature of the system being over-actuated allows for particular actuator degradation and failure. For …
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Decentralized Coordinated Attitude Control of a Formation of Spacecraft
Spacecraft formations offer more powerful and robust space system architectures than single spacecraft systems. Investigations into the dynamics and control of spacecraft formations are vital for the development and design of future successful space missions. The problem of controlling the attitude …