In one embodiment, a rotor hub comprises a yoke for attaching a plurality of rotor blades, a constant velocity joint to drive torque from a mast to the yoke and to enable the yoke to pivot, and a rotor control system configured to adjust an orientation of the plurality of rotor blades. Moreover, the rotor control system comprises: a swashplate, a phase adapter fulcrum, a plurality of actuators controlled based on a flight control input, a plurality of lower pitch links configured to transfer motion between the plurality of actuators and the swashplate, a plurality of phase adjustment levers configured to adjust a control phase associated with motion transferred between the plurality of actuators and the plurality of lower pitch links, and a plurality of upper pitch links configured to adjust a pitch of the plurality of rotor blades, wherein there are more upper pitch links than lower pitch links.

In one embodiment, a rotor hub comprises a yoke for attaching a plurality of rotor blades, a constant velocity joint to drive torque from a mast to the yoke and to enable the yoke to pivot, and a rotor control system configured to adjust an orientation of the plurality of rotor blades. Moreover, the rotor control system comprises: a swashplate, a phase adapter fulcrum, a plurality of actuators controlled based on a flight control input, a plurality of lower pitch links configured to transfer motion between the plurality of actuators and the swashplate, a plurality of phase adjustment levers configured to adjust a control phase associated with motion transferred between the plurality of actuators and the plurality of lower pitch links, and a plurality of upper pitch links configured to adjust a pitch of the plurality of rotor blades, wherein there are more upper pitch links than lower pitch links.

A rotary wing aircraft is provided including a dual counter-rotating, coaxial rotor system having an upper rotor system and a lower rotor system rotatable about a common axis. A plurality of blade assemblies is mounted to a portion of either the upper rotor system or the lower rotor system. A plurality of individually controllable actuators is coupled to each of the plurality of blade assemblies. Each of the plurality of actuators is configured to control movement of the coupled blade assembly about a pitch axis. The rotary-wing aircraft additionally includes a sensor system within an airframe. A higher harmonic control (HHC) controller is arranged in communication with the sensor system and the plurality of actuators to individually control the upper rotor system and the lower rotor system to reduce vibration.

In one embodiment, a rotor hub comprises a yoke for attaching a plurality of rotor blades, a constant velocity joint to drive torque from a mast to the yoke and to enable the yoke to pivot, and a rotor control system configured to adjust an orientation of the plurality of rotor blades. Moreover, the rotor control system comprises: a swashplate, a phase adapter fulcrum, a plurality of actuators controlled based on a flight control input, a plurality of lower pitch links configured to transfer motion between the plurality of actuators and the swashplate, a plurality of phase adjustment levers configured to adjust a control phase associated with motion transferred between the plurality of actuators and the plurality of lower pitch links, and a plurality of upper pitch links configured to adjust a pitch of the plurality of rotor blades, wherein there are more upper pitch links than lower pitch links.

A multi-blade rotor of a rotary wing aircraft, the multi-blade rotor comprising at least one rotor blade that defines a pitch axis and that is provided with an associated pitch-control lever that is operatively coupled to a pitch link rod, the pitch link rod defining a longitudinal axis, wherein the associated pitch-control lever comprises an accommodation that is located on the longitudinal axis of the pitch link rod at a predetermined distance from the pitch axis of the at least one rotor blade, the pitch link rod being operatively coupled to the associated pitch-control lever at the accommodation of the associated pitch-control lever, wherein the predetermined distance is adjustable in order to enable adjustment of track and balance of the multi-blade rotor.

A rotor hub can include a yoke, a mast, and one or more radially oriented actuators. The first radial actuator and the second radial actuator each have a piston configured to impart a translation of the yoke relative to the mast. The radial actuators are configured to attenuate in-plane whirling vibrations. The rotor hub can also have actuators coupled between the mast and the yoke for attenuating flapping and vertical vibrations.

An aircraft is provided and includes a non-rotating frame, an engine disposed in the non-rotating frame, a rotating frame, which is drivable by the engine to rotate relative to the non-rotating frame to generate lift and thrust, the rotating frame including a hub and rotor blades extending outwardly from the hub, an actuation system including electro-mechanical actuators (EMAs) respectively disposed in the rotating frame between the hub and the rotor blades, each EMA including a rotary inductive device, a gear train associated with each EMA and the corresponding rotary inductive device to convert linear displacements of a piston responsive to rotor blade lead/lag into rotation of the rotary inductive device and a controller that controls the rotary inductive device to operate, in a first mode, as a motor which drives the gear train, and, in a second mode, as a generator which is driven by the gear train.

One example of a rotorcraft blade control system includes a mechanical linkage to connect to a rotorcraft blade including a feather axis and a pneumatic muscle connected to the mechanical linkage. The system also includes a movement member connected to the mechanical linkage, the pneumatic muscle and the movement member to move the mechanical linkage to control movement of the rotorcraft blade on the feather axis. The pneumatic muscle can be a first pneumatic muscle and the movement member can be a second pneumatic muscle or a bias spring.

Controlling rotor blades of a rotor assembly includes determining an azimuthal position of a rotor assembly and identifying a lateral control command value, a longitudinal control command value and a collective control command value of a rotor assembly control system. A sine value and a cosine value of the azimuthal position are calculated and separate blade commands signals are generated for each separate blade of the rotor assembly to control a position of each blade independent of each other blade. The blade command signals are generated based on combining the sine and cosine values of the azimuthal position with the lateral control command value, the longitudinal control command value and the collective control command value.

In one aspect, the present disclosure provides a system for reducing vibrations or stresses in a rotor blade system. The system may include at least three rotor blades configured to be rotated about a main rotor axis, where each of the three rotor blades may be adjusted by at least one electrically-adjustable control rod of a plurality of control rods. The plurality of control rods may include a first number of control rods forming a first group, and the plurality of control rods may include a second number of control rods forming a second group. A first circuit for may activate or deactivate the first group of control rods, and a second circuit may activate or deactivate the second group of control rods.