Analysis of non-constant aerodynamic characteristics on flight performance of morphing vehicles

The unsteady aerodynamic effects during morphing significantly influence the flight state accuracy of wide-range morphing aircraft, yet existing studies predominantly rely on quasi-steady aerodynamic assumptions, failing to accurately characterize real-world flight performance. This study aims to quantitatively analyze the impact of unsteady aerodynamic characteristics on the flight performance of morphing aircraft, providing theoretical support for high-precision trajectory optimization and guidance control.

1. Dynamic modeling: a flight dynamics model incorporating unsteady aerodynamic effects was developed to compare performance differences between unsteady and quasi-steady aerodynamic models.

2. Aerodynamic model construction: based on hysteresis loop characteristics, an unsteady aerodynamic model was established to analyze the influence of morphing rate, Mach number, and angle of attack on aerodynamic forces.

3. Trajectory optimization and simulation: the pseudo-spectral method was employed to optimize two typical mission profiles (range coverage and evasive maneuvers), quantifying the impact of unsteady effects on flight trajectories.

1. Quantification of influencing factors: unsteady aerodynamic effects exhibit a positive correlation with morphing rate and a negative correlation with Mach number, with the most pronounced impact occurring in low-altitude, low-speed regimes (Mach 3).

2. Mission performance deviations:

range coverage mission (1000s): range deviation of about 350 m, indicating minor influence;

evasive maneuver mission (250 s): due to aggressive morphing, trajectory deviation reached about 1800 m.

3. No-fly zone constraint impact: higher maneuverability demands lead to more drastic morphing rate variations, amplifying unsteady effects (e.g., coverage blind zone mission deviation reached 1700 m).

1. Unsteady aerodynamic effects predominantly affect low-altitude, low-speed flight regimes (Mach 3), with morphing rate being the dominant factor.

2. High-maneuverability missions (e.g., no-fly zone avoidance) exacerbate unsteady effects, necessitating consideration in trajectory optimization.

3. For high-precision guidance and control, morphing strategies should be optimized to mitigate deviations induced by unsteady effects, though their overall impact remains limited in conventional missions.

4. The proposed methodology is generalizable to other morphing aircraft, offering theoretical foundations for aerodynamic design and trajectory optimization.