Model Reference Adaptive Control for Vertical Gust Mitigation in Commercial Aircraft Longitudinal Dynamics

Vertical wind gusts present significant challenges to commercial aircraft stability, where sudden disturbances can jeopardize passenger safety and control precision. Conventional fixed-gain controllers often struggle to maintain optimal performance under these unpredictable conditions. This study evaluates the potential of Model Reference Adaptive Control (MRAC) to stabilize the aircraft's longitudinal dynamics and enhance passenger comfort during vertical gust encounters. The Airbus A320 aircraft model has been selected as the reference model for this study because it stands as the world's most widely used single-aisle commercial jet and represents a critical baseline for modern fly-by-wire systems facing these aerodynamic challenges. A four-state longitudinal dynamic model of the A320 was developed and rigorously verified against high-fidelity data from the X-Plane 11 flight simulator. A Lyapunov-based MRAC system was designed to track a stable reference model and simulated in MATLAB under discrete 1-cosine gust profiles ranging from light (\((5 \text{ m/s})\)) to severe (\((15 \text{ m/s})\)) intensities. A key result of this research is the finding that lower adaptive rates yield superior stability under high-intensity gust conditions. Contrary to the common intuition that faster adaptation is preferable for rapid disturbances, this study reveals that high adaptive rates induce instability during severe turbulence, whereas lower rates successfully stabilize the aircraft by mitigating excessive controller aggressiveness. The results demonstrate that the MRAC system consistently outperforms the open-loop configuration, significantly reducing pitch oscillations and settling times across all gust scenarios.