Vibration damping system

• US 5,378,974 A
• Filed: 07/02/1993
• Issued: 01/03/1995
• Est. Priority Date: 07/02/1993
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Griffin, Steven F.
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Sircus, Brian
• Application Number:
  US08/088,965
• Time in Patent Office: 550 Days
• Field of Search: 318/611, 318/649, 310/51
• US Class Current: 318/649
• CPC Class Codes: F16F 15/005 using electro- or magnetostrictive actuation means generating of mechanical vibrations operating with electrostriction B06B1/06, with magnetostriction B06B1/08; vehicle suspension arrangements characterised by use of piezoelectric elements B60G17/01941; piezoelectric, electrostrictive and magnetostrictive devices per se H10N30/00
• CPC Class Codes: G05D 19/02 characterised by the use of electric means

Abstract

The smart patch includes two piezoceramic actuators which operate on both sides of a structural member at the same fixed distance from the neutral axis to produce a bending method. The piezoceramic actuators are configured such that when subjected to a voltage, one shrinks and one expands. This provides the moment. One piezoceramic could also be used to provide half the moment provided that it was the same distance from the neutral axis of the structural member. There is a piezoceramic sensor that senses the vibrational mode to be suppressed. Finally there are control electronics that consist of a charge amplifier, a two pole low pass filter and a bridge amplifier. All of these elements are integrated into one entity.

Claims

1. In combination with a mechanical structure which experiences motion-induced vibration, a vibration damping system comprising;

means for electrically sensing the motion-induced vibration in the mechanical structure to produce thereby an electrical vibration measurement signal;

a pair of piezoceramic actuators which are fixed on opposite sides of the mechanical structure at contact points and responding to composite motion command signals to counter all motion induced vibration at their contact points;

a charge amplifier which is electrically connected with said sensing means to receive and amplify the electrical vibration measurement signal therefrom and which produces an amplified vibration measurement signal thereby;

a variable frequency low pass filter which converts the amplified vibration measurement signal of the charge amplifier into a pair of motion command signals;

a bridge amplifier which is electrically connected between the variable frequency low pass filter and the pair of piezoceramic actuators and which receives and amplifies the pair of motion command signals for the pair of piezoceramic actuators; and

an internal means for providing electrical power to said sensing means, said piezoceramic actuators, said charge amplifier, said low pass filter and said bridge amplifier,

wherein said sensing means and said pair of piezoceramic actuators is powered using four 8 volt batteries as said providing means.

2. A vibration damping system, as defined in claim 1, wherein each of said sensing means comprises a piezoceramic sensor which is fixed to said mechanical structure near said contact points to measure the motion-induced vibration at the contact points.

3. In combination with a mechanical structure which experiences motion-induced vibration, a vibration damping system comprising:

means for electrically sensing the motion-induced vibration in the mechanical structure to produce thereby an electrical vibration measurement signal;

a pair of piezoceramic actuators which are fixed on opposite sides of the mechanical structure at contact points and responding to composite motion command signals to counter all motion induced vibration at their contact points; and

a means for electrically converting the electrical vibration measurement signal of the sensing means into the composite motion command signals for the pair of piezoceramic actuators, wherein said converting means, said sensing means and said pair of piezoceramic actuators is powered using four 8 volt batteries.

4. In combination with a mechanical structure which experiences motion-induced vibration, a vibration damping system comprising;

means for electrically sensing the motion-induced vibration in the mechanical structure to produce thereby an electrical vibration measurement signal wherein each of said sensing means comprises a piezoceramic sensor which is fixed to said mechanical structure near said contact points to measure the motion-induced vibration at the contact points;

a pair of piezoceramic actuators which are fixed on opposite sides of the mechanical structure at contact points and responding to composite motion command signals to counter all motion induced vibration at their contact points; and

a means for electrically converting the electrical vibration measurement signal of the sensing means into the composite motion command signals for the pair of piezoceramic actuators, wherein said converting means, said sensing means and said pair of piezoceramic actuators is powered using four 8 volt batteries.