Wideband electromagnetic damping of vibrating structures

• US 4,795,123 A
• Filed: 05/14/1987
• Issued: 01/03/1989
• Est. Priority Date: 05/14/1987
• 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: Forward, Robert L., Griffin, William S.
• Primary Examiner(s): Noland, Tom
• Assistant Examiner(s): Bell, Robert P.
• Application Number:
  US07/049,358
• Time in Patent Office: 600 Days
• Field of Search: 248/550, 248/648, 248/562, 248/636, 248/630, 318/460, 318/605, 318/649, 318/651, 318/648, 188/378, 267/136, 73/668, 74/574
• US Class Current: 248/550
• CPC Class Codes: F16F 15/02 Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems F16F15/005 takes precedence ; layered products B32B; suppression of vibration in ships B63; relieving load on bearings, using magnetic means F16C39/06

Abstract

The damping of vibrations in a mechanical structure is accomplished while minimizing the impact on the design and operation of the structure through the use of a plurality of attachable vibration damping elements. Each vibration damping element contains: an accelerometer, an integrator, mixer, power amplifier, and a force actuator. The accelerometer measures the motion of the vibration in the structure at its attachment point and produces an acceleration measurement signal. The integrator integrates the acceleration measurement signal to produce a velocity measurement signal. The mixer produces a composite motion signal by mixing the acceleration measurement signal with the velocity measurement signal. The power amplifier adjusts the phase and amplitude of the composite motion signal to drive the force actuator to damp the sensed vibration along one dimension at the attachment point of the force actuator. By placing three vibration damping element at right angles to each other at a location on the structure, three dimensional vibration damping is obtained at that point.

Claims

1. A vibration damping system which damps motion-induced vibration in a mechanical structure using a plurality of vibration damping elements, each of which forms an axis by being fixed to said mechanical structure at a contact point, each of said vibration damping elements producing a mechanical force to dampen vibration along said axis at said point of contact, said plurality of vibration damping elements thereby collectively damping said motion-induced vibration in said mechanical structure, each of said vibration damping elements comprising:

an accelerometer which is housed in said vibration damping element and which produces an acceleration measurement signal by measuring acceleration along said axis of its vibration damping element;

an integrator which produces a velocity measurement signal by integrating said acceleration measurement signal received from said accelerometer;

a mixer which produces a combined motion signal by mixing said velocity measurement signal received from said integrator with said acceleration measurement signal received from said accelerometer;

a power amplifier which produces a composite motion signal by amplifying and adjusting the phase of said combined motion signal received from said mixer;

a means for attaching said vibration damping element to said mechanical structure; and

a force actuator which contains said accelerometer and is attached to said structure by said attaching means at one end, and which is electrically attached to said power amplifier at its other end, said force actuator receiving and translating said composite motion signal into mechanical force to dampen vibration.