Acceleration Flight Control for Reduced Gravity Flight in Large Fixed-Wing Aircraft

Access to reduced-gravity environments is a cornerstone of space research, enabling scientific experiments in space-like conditions. While parabolic flights have long served as an accessible platform for microgravity studies, their reliance on manual piloting limits precision and repeatability. This paper introduces an autonomous flight control framework designed to execute reduced-gravity maneuvers in large fixed-wing aircraft. The proposed system regulates all four phases of the maneuver by commanding a reference acceleration profile. This approach enables precise control over the aircraft’s acceleration, ensuring consistent reduced gravity conditions critical for experimental applications. The control architecture comprises three specialized controllers: one each for tangential and normal acceleration regulation and another for minimizing angle-of-attack variations to dampen pitch oscillations. The proposed framework is evaluated on a nonlinear Boeing 747 model implemented in MATLAB Simulink. Simulation results show that the controller maintains residual accelerations within $$\pm 0.02\,g$$ for zero-, lunar-, and Martian-gravity manoeuvres, matching the error margins reported in published flight data. Key challenges are addressed, such as non-minimum phase dynamics, altitude-dependent air density variations, and pitch oscillations at the center of gravity. These findings contribute to the advancement of autonomous flight control for more reliable and precise reduced-gravity research.