An analytical model for ACSR approach to vibration reduction in a helicopter rotor-flexible fuselage system

This paper describes the development of a coupled rotor-flexible fuselage model which is suitable for simulating vibration reduction based on the active control of structural response (ACSR) approach. The rotor is an N-b-bladed aeroelastic model, with coupled flap-lag-torsional dynamics for each blade. Moderate blade deflections are included, together with complete coupling between rotor and fuselage dynamics. This aeroelastic response model is combined with a control algorithm based on an internal model principle. The control scheme effectively reduces vibrations to 0.05g levels or lower, using reasonable actuator forces. The baseline vibration levels in the fuselage are relatively high. This is due to the lack of damping modelling in the fuselage. With the actuators engaged, the hub loads remain virtually unchanged and therefore this control approach has no influence on vehicle airworthiness.