Attitude control and design of satellites with flexible structures using Inverse Simulation

Gordon, Robert Alexander Douglas (2025) Attitude control and design of satellites with flexible structures using Inverse Simulation. PhD thesis, University of Glasgow.

Abstract

Ensuring the stable and accurate pointing of a satellite’s instrumentation is the task of the attitude control system, a problem made substantially more complex by the influence of flexible structural dynamics often exhibited by satellites. The inclusion of flexible structures is necessitated by the desire to maximise the satellite’s functionality while ensuring its mass and form factor are conducive to being launched into orbit. Commonly, satellites will make use of lightweight and flexible, deployable appendages to facilitate the mounting of additional instrumentation, larger antennas, and extra solar panels. In addition, the construction of larger flexible space structures, using advancing orbital assembly and manufacturing technologies, opens the door to complex missions such as space stations, space telescopes, large solar sail spacecraft, orbital solar reflectors, and space-based solar power satellites. While the variety of applications for flexible space structures may be wide, each will require stable and accurate attitude control of the satellite platform.

A range of attitude control methodologies for satellites with flexible structures has been studied previously, each attempting to achieve good tracking performance by imitating the satellite’s inverse dynamic behaviour. Many of these approaches are based on analytical techniques, requiring the control solution to be derived from a mathematical model that approximates the satellite’s dynamics. This thesis proposes that, if a sufficiently accurate mathematical model is available, then an alternative, highly-computational, numerical approach known as Inverse Simulation could instead be employed. Having already been demonstrated as a viable control methodology in several fields of research, such as planetary rovers and helicopters, this thesis will investigate the application of the generalised integral Inverse Simulation algorithm for attitude control of satellites with flexible structures.

As part of the thesis, several mathematical models for the Inverse Simulation numerical process to solve are derived. This includes models that assume only rigid body behaviour, those that consider the flexible dynamics of deployable appendages, and finally a modular model for large flexible space structures. These models also account for the dynamics of various actuator types, some of which may have an impact on the stability and performance of the integral Inverse Simulation algorithm.

The attitude reorientation manoeuvres used to drive the Inverse Simulation solution are provided using a mixture of polynomials, spherical interpolation, and splines. Before implementation as a control technique, the effect of each of the Inverse Simulation’s hyperparameters is studied to optimise the accuracy and computational efficiency of the algorithm. Additionally, issues of numerical stability specific to the application of satellites with flexible structures are identified and addressed.

It is found that the integral Inverse Simulation algorithm does provide a more flexible, practical, and accurate method for solving the inverse attitude dynamics of a satellite with flexible structures than alternative analytical techniques. The generality of the numerical process allows for a ready-to-go control solution, provided a suitable up-to-date model is available. The control methodology is however highly sensitive to model uncertainty and requires significant computational power to compute, somewhat limiting its practical use. Additional online parameter estimation and improved computational efficiency of the algorithm will therefore be required if the control approach is to be realistically used.

Inverse Simulation is also employed to improve attitude path planning, evaluating the performance of prospective paths to minimise excitation of the flexible structural dynamics. One of the most common applications of Inverse Simulation within the literature, as a conceptual design tool, is also demonstrated for satellites with flexible structures. It is shown that Inverse Simulation allows for the performance of different actuator configurations for large space structures to be assessed, informing designs that minimise structural deformation during slew manoeuvres. A final contribution of the thesis is the development of a faster integral Inverse Simulation algorithm based on Broyden’s method, improving performance particularly when a large number of inputs/actuators are in use.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: T Technology > T Technology (General)
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Supervisor's Name: Ceriotti, Dr. Matteo and Worrall, Dr. Kevin
• Date of Award: 2025
• Depositing User: Theses Team
• Unique ID: glathesis:2025-85386
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 13 Aug 2025 08:47
• Last Modified: 13 Aug 2025 08:49
• Thesis DOI: 10.5525/gla.thesis.85386
• URI: https://theses.gla.ac.uk/id/eprint/85386

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