Adaptive Control of Thrusters to Account for Deficiencies in Actuator Effectiveness and Model Uncertainties

<p>Future space missions are expected to become ever more ambitious and challenging. A successful mission requires advanced and resilient control algorithms that enable missions, such as satellite refueling, on-orbit inspection, and end-of-life servicing. This thesis explores the development and application of robust 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 stability and command tracking, a novel controller is designed and augmented with sliding mode control, adaptive control, and control allocation algorithms to provide resilient performance despite the presence of model inaccuracies, external disturbances, and actuator deficiencies. The over-actuated spacecraft is equipped with 8 cold-gas thrusters, and the system dynamics are modeled using a state-space representation. A Lyapunov stability analysis is conducted to verify the stability of the closed-loop system with the proposed method. Simulation results show that the proposed controller effectively incorporates changes in actuator effectiveness and dynamic uncertainties, improving trajectory tracking. The controller is further validated through experimental testing with a physical vehicle to demonstrate the practicality and effectiveness of the proposed methods in real-world applications. The experimental testbed consists of vehicle equipped with linear air bearings that work in conjunction with an epoxy floor to induce practically frictionless motion. A motion-capture camera system provides positional state feedback, and an onboard RaspberryPi4 runs the controller while simultaneously logging telemetry data. This work contributes to the field of resilient control in aerospace engineering by providing a reliable solution for managing actuator degradation and system uncertainties, making it particularly suitable for space missions where long-term autonomy and fault tolerance are critical.</p>

Name thesis:degree_name

Master of Science in Aerospace Engineering

Level thesis:degree_level

Thesis - Open Access

Discipline thesis:degree_discipline

Aerospace Engineering

Year dc:date.available

2025

Author dc:creator

• Stanko, Matthew

• Adaptive Control; Adaptive Allocation; Implementation; Experimental Validation; spacecraft dynamics; thruster actuation
• Navigation, Guidance, Control and Dynamics

Repository record dc:identifier

https://commons.erau.edu/edt/994

OAI identifier oai:identifier

oai:commons.erau.edu:edt-1934