Adaptive Control Model for Nonlinear Pilot-Induced Oscillations Caused by Multimodal Switching

In multimodal flight control systems, nonlinear pilotinduced oscillation (PIO) caused by modal switching poses a serious threat to flight safety. Existing pilot models demonstrate high-frequency oscillatory limit-cycle characteristics during modal switching, with a tendency to induce type III PIO. To address this, an improved adaptive pilot model is developed to enhance the pilot's adaptation to sudden changes in vehicle dynamics through dynamic gain parameter adjustment, which can reflect the characteristics of pilot control behavior accurately. On this basis, an intelligent auxiliary controller is designed based on integrating adaptive sliding mode control to improve the highfrequency oscillations caused by modal switching. Simulation results demonstrate that the improved pilot model combined with the auxiliary controller leads to significant reductions in both oscillation amplitude and tracking error, while keeping the system outside the PIO-prone region. These improvements substantially enhance system stability and robustness. This study presents an effective solution to nonlinear oscillation suppression in multimodal flight control.