Horizontal Stabilator Utilization for Post Swashplate Failure Operation on a UH-60 Black Hawk Helicopter

摘要

The present study focuses on using the stabilator as a redundant control effector for main rotor swashplate servo actuator failure compensation in a UH-60A Black Hawk in cruise. A simulation model based on Sikorsky's GenHel model is modified to simulate main rotor servo actuator failure. A model-following, linear dynamic inversion controller is implemented and modified to account for locked actuator positions. Upon failure of the forward (S_(fwd)) or aft actuator (S_(aft)), compensation is achieved by partial reallocation of longitudinal control to the stabilator through the control mixer (relating pilot stick inputs to servo actuator positions), due to its ability to generate pitching moments in forward flight. The mechanical mixer (relating servo actuator positions to blade pitches) remains unchanged. Longitudinal control is shared between the working actuator along the longitudinal axis (i.e., S_(aft), if S_(fwd) is locked or vice versa) and the stabilator postfailure. Control authority is reassigned such that 100% of longitudinal stick corresponds to a full range of motion of the stabilator postfailure. The reallocation of authority to the stabilator changes the control coupling matrix, (CB)~(-1), used in the inner loop. However, the feedback control laws (feedback gains) remain unchanged. The following key conclusions can be drawn from this study.