Active vibration control of rotorcraft driveshaft-airframe dynamics

The active vibration control of a coupled fuselage-tailrotor drivetrain structure is presented. A finite element method is developed for this type of structure. A baseline study on the model shows that shaft imbalance and aerodynamic loading have a significant effect on hanger bearing loads and flexible coupling misalignments. Additionally, it indicates that by properly accounting for the actuator gap size with the control law, non-contacting magnetic actuators can be used in the control system. For this particular model, a 95% bearing load reduction in forward flight is achieved with two actuators which weigh three pounds and consume three amps of current.