An aircraft is provided and includes a rotor, which is rotatable relative to an airframe, a rotor, which is rotatable relative to the airframe and which generates a rotor induced vibration, an engine to generate rotational energy, a drive portion to transfer the rotational energy from the engine, a gearbox disposed to transmit the rotational energy from the drive portion to the rotor to drive rotor rotation, support members connecting the gearbox to the airframe and an actuation system configured to generate an anti-vibration load applicable to the gearbox via an actuator comprising an actuator element disposed along one of the support members and a stinger element extending from the actuator element to a connection point of the support member and the gearbox to transmit a portion of the anti-vibration load from the actuator element to the connection point to counter the rotor induced vibration at the gearbox.

A rotorcraft extends longitudinally along a first anteroposterior plane separating a first side from a second side of the rotorcraft. The rotorcraft includes at least one main rotor, an auxiliary rotor, and at least one steerable airfoil. The rotorcraft further includes a processor unit connected to a first measurement system configured to measure a current value of a speed parameter (V) of the rotorcraft and to a second measurement system configured to measure a current value of a power parameter (W) of a power plant of the rotorcraft. The processor unit is configured to adjust the deflection angle of the airfoil as a function of the current speed and power parameter values (V, W) to cause the auxiliary rotor to move towards at least one predetermined operating point which optimizes performance of the rotorcraft and minimizes noise generated by the auxiliary rotor.

Actuators are components of machines, which move and/or control a mechanism or system. During operation, actuators can experience regeneration events, with the actuator actually generating excess energy (e.g., regenerative energy) which must be stored or dissipated to avoid damaging the power supply. An actuator motor controller is configured to implement field oriented voltage control and flux weakening voltage control without current sensors. Dissipating regenerative energy includes providing a motor controller to command a motor drive to modify an input voltage, or to dissipate regenerative energy in a dump circuit. This command can cause motor windings to dissipate regenerative energy. Systems having a plurality of actuators distribute regenerative energy from one actuator to another. A central controller provides centralized regeneration dissipation control for the plurality of actuators. A power distribution unit includes a dump resistor to dissipate regenerative energy in addition to or instead of in the actuators.

A rotorcraft having an antivibration system, the antivibration system being arranged at the interface between a fuselage of the rotorcraft and a casing of a main power transmission gearbox, or “MGB”, in order to transmit rotary motion generated by an engine of the rotorcraft to a main rotor providing the rotorcraft at least with lift, and possibly also propulsion, the antivibration system including calculation means for analyzing as a function of time the dynamic excitation and the resulting vibration transmitted to the fuselage of the rotorcraft.

A method for predicting vibrations in an aircraft comprising an active vibration reduction system includes estimating a first vibration amplitude or frequency resulting from adjustments by the active vibration reduction system and the respective sensitivities of the aircraft depending on the flying state using a statistical mathematical process, recording a second vibration amplitude or frequency by a sensor, generating a pseudo-vibration profile by combining the first and second vibration amplitudes or frequencies, comparing the pseudo-vibration profile with a predefined target vibration profile, and outputting a signal when a specific threshold value has been exceeded.

Provided is a vibration control system for a compound helicopter with a rotor and a fixed wing. The fixed wing includes a movable flap that is mounted on a rear edge of the fixed wing. The vibration control system periodically moves the movable flap so as to periodically change lift of the fixed wing such that vibration aerodynamically generated by the fixed wing is in anti-phase with vibration caused by rotation of the rotor.

Systems and method for active vibration control on an aircraft. An active vibration control system (AVCS) is configured for an aircraft having an aircraft structure and a gun. The AVCS includes at least one control sensor on the aircraft, at least one force generator on the aircraft, and at least one controller in electronic communication with the sensor and the force generator. The controller is configured for determining, using the at least one control sensor, force generating commands for controlling vibrations acting on the aircraft structure, sending the force generating commands to the at least one force generator, causing the at least one force generator to produce a vibration canceling force, determining that the gun is firing, and in response to determining that the gun is firing, determining different force generating commands and sending the different force generating commands to the at least one force generator.

A rotor for an aircraft is described that has a mast, an attenuating device to attenuate the transmission of vibrations from the mast in a plane orthogonal to the first axis, and a transmission device interposed between the mast and the attenuating device; the attenuating device comprises a first and a second mass unit with a first and a second mass rotatable about the first axis with a first and a second rotational speed, two control units operable to cause an additional rotation of at least one of the first and second masses, and a first and a second support assembly carrying the first and second masses; each control unit controls the angle between the first and second masses and comprises a set of drive gear teeth integral with the first support assembly, a cogwheel with a set of control gear teeth meshing with the drive gear teeth, and an actuator to cause the rotation of the cogwheel about a second axis and of the first mass about said first axis.

A liquid inertia vibration elimination (“LIVE”) system for a rotor system having n number of blades. The LIVE system includes a first tuned vibration reduction component configured to provide a maximum vibratory isolation at a frequency below 2*n/rev and a second tuned vibration reduction component configured to provide a maximum vibratory isolation at a frequency above 3*n/rev.

A rotor for an aircraft is described that comprises: a hub rotatable about an axis and, in turn, comprising a plurality of blades; a mast connectable to a drive member of the aircraft and connected to the hub to drive the hub in rotation about the axis; and damping means to dampen the transmission of vibrations to the mast in a plane orthogonal to the axis; the damping means comprising at least a first mass and a second mass that can eccentrically rotate about the axis with a first and a second speed of rotation, respectively; the first mass and second mass are operatively connected to the mast to generate, respectively, a first and a second damping force on the mast having a main component in a direction radial to the axis; the rotor comprises a transmission unit, which is interposed between the mast and the first and second masses so as to drive the first and second masses in rotation.