Zoom Link: https://kaust.zoom.us/j/7581373044?omn=96932754095

Committee Members' Information:

Ph.D. Advisor: Eric Feron

External Examiner: Khalid Juhany

Committee Chair: NorEddine Ghaffour

4th Committee Member: Deanna Lacoste

Abstract

The creation of reduced-gravity environments is a valuable tool for scientific and technological advancements across diverse fields, including materials science, biology, and aerospace engineering. Yet, conventional methods like manually piloted parabolic flights suffer from significant limitations in precision, repeatability, and versatility. This dissertation addresses these challenges by introducing a novel, unified autonomous flight control framework for fixed-wing aircraft designed to execute precise and reliable reduced-gravity maneuvers. The core of the proposed system is an acceleration-feedback architecture that directly regulates the aircraft’s tangential and normal accelerations, enabling it to autonomously manage all four phases of the parabolic maneuver. The control design explicitly overcomes key challenges inherent in this application, including the mitigation of non-minimum phase behavior through strategic accelerometer placement and the robust rejection of unmodeled aerodynamic drag forces without requiring direct measurement or estimation. The framework’s performance, adaptability, and scalability are rigorously validated through high-fidelity, nonlinear simulations on two vastly different platforms: a large airliner and a high-speed, fixed-wing mini-UAV. Across all simulated scenarios—including zero, lunar, and Martian gravity levels—the controller successfully achieves and maintains the target -levels with high precision, with a duration and quality that meet or exceed the defined benchmarks (residual accelerations within ±0.02 g for 10 seconds). This research establishes a versatile and robust control strategy applicable across a wide spectrum of aircraft, advancing the state of autonomous flight for scientific applications. By enhancing the accuracy, reliability, and accessibility of aircraft based reduced-gravity platforms, this work provides a foundational tool for future research in space science and exploration.

Biography

Mohammed Aldosari is currently pursuing his PhD in Mechanical Engineering at KAUST, where he also earned his MSc degree. He completed his BSc in Aerospace Engineering at KFUPM. Presently, he works as a researcher at the Center of Excellence for Aeronautics & Astronautics at KACST.