Detection and Avoidance of Main Rotor Hub Moment Limits on Rotorcraft

摘要

There is interest in developing carefree maneuvering capability on future rotorcraft. This has driven the need for advanced algorithms that predict the onset of structural limits and cue the pilot using tactile feedback. A new method is presented for the detection and avoidance of static load limits on the main rotor hub. An algorithm was developed that uses linear models to estimate constraints on longitudinal and lateral cyclic stick positions that ensure the transient response of hub moments remain bounded within prescribed limits. The system was tested using a high-fidelity nonlinear simulation of a UH-60A helicopter (GENHEL). The system was shown to be successful in simultaneously constraining stick travel in both lateral and longitudinal axes to prevent hub moment limit violations. The most critical conditions occurred during control reversals, at which point the system effectively imposed rate limits on the stick motion. The algorithm was shown to be robust to changes in aircraft weight and c.g. location.