A distributed atmospheric turbulence model is developed for helicopter flight simulation. The impacts of different aerodynamic surfaces on handling qualities with helicopter in turbulence are analyzed. Both helicopter flight dynamic model and turbulence model are validated against the flight test data, which shows that the proposed model improves the accuracy of the simulation of rotor blade element turbulence model on the vertical axis within the interested frequency range for handling-quality analysis. A quantitative index is developed to study the impact of turbulence on helicopter handling qualities by analyzing the effects of different aerodynamic surfaces on helicopter response to turbulence. The results show that the main rotor has the dominant effects on both the heave and roll handling qualities, the airframe has the primary effect on the pitch handling quality, and the tail rotor has an important effect on the yaw handling quality. Furthermore, the impacts of the main rotor in turbulence on the helicopter handling qualities of roll, pitch, and yaw increase with the forward speed at lower speeds but decrease at higher speeds. The increment trend with the forward speed of the airframe’s impacts on the pitch and yaw handling qualities reduces at higher speeds.

A helicopter flight control system with rotor-state feedback to improve turbulence alleviation in hover is presented. First, a flight dynamic model coupled with turbulence model is developed and validated. Then, an integrated control strategy with a rotor-state feedback control law is proposed based on the baseline control system. The feedback gains of body and rotor states are designed in synergy to improve turbulence alleviation in the interested frequency range of handling qualities. Subsequently, the effects of the rotor-state feedback gains on both the stability of rotor dynamics and helicopter turbulence alleviation are analyzed in detail. Finally, the effectiveness of the integrated control system is evaluated with linear analysis in frequency domain and nonlinear simulation in time domain. The results indicate that with the rotor-state feedback control law integrated into the control system, the helicopter turbulence alleviation in the interested frequency range is improved with less degradation in helicopter stability margins, and the roll and pitch rate responses of helicopter to turbulence, measured with Root-Mean-Square (RMS) values, are reduced by more than 50% and 35% respectively.