Vibration control systems
An active vibration control system includes an electromagnetic actuator; a magnetic element; and a solenoid, the electromagnetic actuator being operable to apply a force on a base structure to which the active vibration control system is attachable such that vibrations of the base structure are actively controllable by the application of said force, wherein the electromagnetic actuator is operable to cause movement of the magnetic element through the solenoid and the solenoid is operable to apply a force on the magnetic element.
1 . An active vibration control system comprising: an electromagnetic actuator; a magnetic element; and a solenoid; the electromagnetic actuator being operable to apply a first force on a base structure to which the active vibration control system is attachable such that vibrations of the base structure are actively controllable by the application of said first force, wherein the electromagnetic actuator is operable to cause movement of the magnetic element through the solenoid, and the solenoid is operable to apply a second force on the magnetic element,
wherein the electromagnetic actuator is supplied with an AC current, and the solenoid is supplied with a DC current.
2 . The active vibration control system of claim 1 , wherein the electromagnetic actuator comprises a coil and a moveable member, the moveable member comprising a permanent magnet, wherein current flowing through the coil in the presence of a magnetic field of the permanent magnet causes displacement of the moveable member, thereby to cause movement of the magnetic element through the solenoid to apply a third force on the solenoid and thereby on the base structure.
3 . The active vibration control system of claim 1 , comprising a current flow control system operable to control flow of current to the electromagnetic actuator and/or flow of current to the solenoid.
4 . The active vibration control system of claim 3 , wherein the current flow control system is operable to control the flow of current to the electromagnetic actuator and/or the solenoid thereby to tune, control, or adjust a mode of vibration of the active vibration control system.
5 . The active vibration control system of claim 1 , wherein the solenoid is operable to apply a third force on the magnetic element thereby to oppose movement of the magnetic element through the solenoid.
6 . The active vibration control system of claim 1 , wherein the magnetic element is connected to the moveable member of the electromagnetic actuator.
7 . The active vibration control system of claim 6 , wherein the magnetic element is fixedly or resiliently connected to the moveable member of the electromagnetic actuator.
8 . The active vibration control system of claim 1 , wherein the solenoid is attached to the base structure.
9 . The active vibration control system of claim 8 , wherein the solenoid is fixedly or resiliently attached to the base structure.
10 . The active vibration control system of claim 1 , wherein the magnetic element is operably connected to a shaft, the shaft being resiliently attached in the active vibration control system.
11 . The active vibration control system of claim 1 , wherein the solenoid is operable to apply negative stiffness.
12 . An active vibration control apparatus comprising a proof-mass and a plurality of active vibration control systems as claimed in claim 1 .
13 . The active vibration control apparatus of claim 12 , wherein each active vibration control system is resiliently connected to the proof-mass.
14 . A vehicle comprising the active vibration control apparatus of claim 12 .
15 . A vehicle comprising the active vibration control system of claim 1 .
16 . The vehicle of claim 15 , wherein the base structure forms part of the vehicle.
17 . The vehicle of claim 15 , wherein the vehicle is one of a ground-based vehicle, an aquatic vehicle, or an airborne vehicle.
18 . The active vibration control system of claim 1 , comprising a current flow control system operable to control flow of current to the electromagnetic actuator and flow of current to the solenoid.
19 . A method of actively controlling vibrations of a base structure, the method comprising:
providing an active vibration control system that includes an electromagnetic actuator, a magnetic element, and a solenoid, wherein the electromagnetic actuator is operable to cause movement of the magnetic element through the solenoid and the solenoid is operable to apply a first force on the magnetic element;
attaching the active vibration control system to the base structure; and
operating the electromagnetic actuator to apply a second force on the base structure,
wherein the electromagnetic actuator is supplied with an AC current, and the solenoid is supplied with a DC current.
20 . An active vibration control system comprising:
an electromagnetic actuator including a coil and a movable member having a permanent magnet, wherein a current flowing through the coil produces a force which acts on the permanent magnet, thereby causing movement of the moveable member relative to the coil;
a magnetic element connected to movable member of the electromagnetic actuator; and
a solenoid, wherein a current flowing through the solenoid produces an attraction of the magnetic element, thereby causing movement of the magnetic element through the solenoid, and wherein a magnitude of the attraction is a function of an extent to which the magnetic element extends through the solenoid such that the magnetic element experiences a negative stiffness.