Modeling and Control Methods for Future Vertical Lift Rotorcraft Fatigue Reduction

Rotorcraft undergo constant vibratory excitation due to unsteady airloads resulting from the rotor rotation even in steady state flight conditions. These vibratory loads are a challenging aspect in terms of both operational cost and flight safety. This research aims at developing rotorcraft loads analysis methods with fatigue damage estimation and fatigue reduction controllers to augment a technical base toward the goal of ``zero-maintenance" (or minimum maintenance) for significantly reduced operational costs and enhanced flight safety. The research emphasizes the development of a simulation based predictive capability by coupling a state-of-the-art rotorcraft loads prediction tool with fatigue damage analysis to aid in the development of fatigue mitigation controls. Extensive simulation testing will be conducted to evaluate the effectiveness of the fatigue mitigation controller and its impact on the primary flight controls to ensure that both the flight performance and flying qualities are preserved.