A method, system and devices to selectively control modal vibrations in an elastic panel with a number of force actuators distributed throughout the surface of the elastic panel to excite/depress the response of one or more vibrational resonant modes included in a prescribed subset. The force actuators are disposed such that prescribed modal excitation/depression may be realized when the actuators are driven by a common source signal.

An energy absorption system, for absorbing an impact energy imparted to a subject upon landing on a surface, includes a mass containment vessel fixed to the subject and a plurality of electromagnets disposed at fixed positions relative to the mass containment vessel. The mass containment vessel may contain one or more mass elements movably disposed therein. A controller may be configured to charge one or more of the electromagnets upon an impact of the subject with the surface to move the mass element(s) toward the surface by electromagnetic force. Alternatively, the energy absorption system may include a pulley system operable to mechanically move one or more mass elements along an axis, a multi-axis joint connecting the pulley system to the subject, and a controller configured to operate the pulley system upon an impact of the subject with the surface to mechanically move the mass element(s) toward the surface.

A system and method include with a mass damper for reducing vibrations in a structure or machine. The mass damper includes a frame that is movable linearly along a base, which includes a track gear. A flywheel is in geared engagement with the track gear so as to be rotationally driven as the frame moves linearly relative to the base. A rotation damper is mounted on the frame and is geared engagement with the flywheel, the rotation damper producing a counter-torque against rotation of the flywheel that is proportional to a rotational velocity of the flywheel. The rotation damper has an electrical characteristic that is automatically adjusted to change the counter-torque and tune the mass damper.

A highly-efficient new-energy vibration controller integrating passive, semi-active and active control, including a multi-cavity beam, a battery assembly, a wound magnetic device, a damping piezoelectric device and an inertia mass assembly. The wound magnetic device includes a connecting rod, an electromagnetic wire wound on a bottom end of the connecting rod and a magnetic box arranged at a bottom of the inertia mass assembly. A top end of the connecting rod is fixedly connected to a bottom of the multi-cavity beam. The bottom end of the connecting rod passes through a center through hole of the inertia mass assembly and arranged in the magnetic box. The magnetic box is provided with a magnetic field. The damping piezoelectric device is sleevedly arranged on an outer wall of the connecting rod. The damping piezoelectric device and the wound magnetic device are both electrically connected to the battery assembly.

An active inertial damper system (100) and method for damping vibrations (V1,V2) in a structure (11). An inertial mass (2) is supported by a support frame (1) via spring means (3) to form a mass-spring system (2,3) having a resonance frequency (fn). A controller (6) is configured to control a force actuator (4) to adapt the driving force (Fd) as a function of measured vibrations (V1,V2). The controller (6) comprises a filter (H) determining a magnitude (M) of the driving force (Fd) as a function of frequency (f) for the measured vibrations (V1,V2) in the structure (11). The filter (H) is configured to provide an anti-resonance dip in the magnitude (M) of the driving force (Fd) at the resonance frequency (fn) of the mass-spring system (2,3) to suppress resonant behaviour of the mass-spring system (2,3) itself.

A rotor for a hover-capable aircraft is described that comprises: a hub rotating about an axis and, in turn, comprising a plurality of blades, a mast connectable to a power unit of the aircraft and operatively connected to the hub to drive the hub in rotation about said axis, and an attenuating device to attenuate the transmission of vibrations from the mast to the aircraft parallel to said; the attenuating device, in turn, comprising a casing, a first mass free to oscillate parallel to said axis with respect to the casing and elastically connected to the casing, a second mass free to oscillate parallel to said axis, connection means adapted to make the first and second masses integrally movable along said axis when the angular speed of the mast assumes a first value, and actuator means activatable to decouple the first and second masses when the angular speed of the mast assumes a second value, different from the first value.

A method, system and devices to selectively control modal vibrations in an elastic panel with a number of force actuators distributed throughout the surface of the elastic panel to excite/depress the response of one or more vibrational resonant modes included in a prescribed subset. The force actuators are disposed such that prescribed modal excitation/depression may be realized when the actuators are driven by a common source signal.

An actuator device for active reduction, damping and/or absorption of vibrations, in particular of vibrations generated by an external device, includes at least one movably supported armature element and at least one permanent magnet, which is coupled with the armature element, in particular an outer side of the armature element, and which extends around the armature element at least section-wise, in particular in a ring shape, wherein at least in an axial direction of the armature element, which runs at least substantially parallel to a main movement axis of the armature element, the permanent magnet is encapsulated by the armature element, in particular at least on two sides.

A system may detect a vibration being applied to a tuned vibration absorber. The tuned vibration absorber may include a beam, a mass, springs, a sensor, and an actuator. The mass may be disposed on the beam at a current position. The actuator may be configured to adjust a position of the mass on the beam. The system may identify a target position of the mass on the beam based on the detected vibration. The system may generate a drive signal, based on the target position, to control the actuator to adjust the position of the mass on the beam. The system may control the actuator to adjust the position of the mass from the current position on the beam to the target position on the beam to attenuate the vibration.

An active anti-vibration device 10 includes a pair of elastic connecting parts 20 and 30, a rod body 40 that connects the pair of elastic connecting parts, an inertial mass 52 that is supported by the rod body, a drive part 58 that reciprocates the inertial mass in an axial direction of the rod body, and a controller 90 that is configured to be able to perform acceleration feedback control to control the drive part so that a first force proportional to an axial acceleration of the rod body is generated.