Finite-time deep stall recovery control for fighter aircraft using forced oscillation

To address the problem of rapid and stable recovery from deep stall in fighter aircraft, a finite-time control method based on forced oscillation is proposed. To characterize the dynamics of deep stall state, bifurcation theory is employed for analysis, and the region of attraction boundaries is determined through backward-time integration. To generate precise recovery commands from mechanistic perspective, an extended bifurcation analysis is conducted, and forced oscillation commands corresponding to unstable bifurcation points are incorporated into the controller design. To handle time-varying disturbances and aerodynamic parameter perturbations during deep stall, a disturbance observer is designed to estimate lumped uncertainties while neural networks compensate for model uncertainties, and the deep stall recovery controller is obtained by combining with angle of attack tracking error feedback. The system signals involved in the Lyapunov function are proved to be bounded and the sliding mode surface converges in finite time. Simulation results show that the proposed method can reduce the fighter aircraft's angle of attack to a safe zone while maintaining stable controllability, and achieve rapid and smooth recovery from deep stall conditions.