Dynamic Analysis for Rotor/Fuselage Coupling Stability of a Bearingless Rotor Helicopter

A structural dynamics modeling method of the multiplexing rotor hub has been developed for the new configuration of bearingless rotor and the hub configuration with complex power transmission path. The technique of modal synthesis has been adopted for the helicopter development trend with a new rotor configuration and multi-rotor, which to synthesizing model the multi-body dynamics coupled systems of the rotor and fuselage. The dynamic differential equations of rotor and fuselage coupled system has been deduced by utilizing Hamilton principle, then the modal synthetic-analytical model of rotor/fuselage coupling dynamics can be established. With the experimental data of ground and air resonance of a bearingless rotor scaling model on dynamic test-bed, the lead-lag regressive mode damping of theoretical calculation agree well with the test results. The calculating result for the actual case is in accordance with the experiment. The study verifies the validity of the algorithm and correctness of the method. This analysis method used for ground resonance and air resonance stability of a bearingless rotor helicopter can give out the results according with real helicopter engineering tests.