Vibration control

An active mass damper system to reduce vibrations in a structure, the system comprising a stiff frame securable to a structure, the system further comprising one or more accelerometers which take instantaneous absolute measurements of vibrations in a structure, means for feeding the instantaneous absolute measurements to a control unit and using this to drive an actuator, in which the actuator moves a mass block substantially vertically in the stiff frame and the system comprises linear bearings to ensure substantially vertical motion of the mass block, the stiff frame transmits dynamic forces generated by the internal motion of the mass block to cancel out or dampen vibrations in the structure in use.

An active mass damper device for reducing vibrations in a structure, the device comprising a stiff frame, the device further comprising one or more accelerometers which take instantaneous absolute measurements of vibrations in a structure, means for feeding the instantaneous absolute measurements to a control unit and using this to drive an actuator, in which the actuator moves a mass block substantially vertically in the stiff frame and the device comprises linear bearings to ensure substantially vertical motion of the mass block, the stiff frame transmits dynamic forces generated by the internal motion of the mass block to cancel out or dampen vibrations in the structure in use.