Active vibration isolation system employing an electro-rheological fluid
AssigneeBarry Wright Corporation
InventorDale W. Schubert
Life of this patent
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Abstract
An active vibration isolation system employing an electro-rheological fluid comprises a damper having a servovalve fluidically coupling a load supporting actuator to an accumulator. The servovalve includes an orificed plate arrangement, across which a voltage potential is impressed in accordance with a command signal derived from response sensors. The viscosity of an electro-rheological fluid contained within the servovalve reacts to the voltage potential so as to regulate the fluid flow. In this manner the damping coefficient is modulated to as to approximate a "sky-hook" damper.
Claims24
A viscous damper comprising:
- (a) means for deriving a first signal representative of the velocity of relative motion between first and second elements connected by said viscous damper for the reduction of transmitted excitations therebetween;
- (b) means for deriving a second signal representative of the velocity of one of said first and second elements;
- (c) means for generating a command signal in response to the ratio of said second signal to said first signal;
- and
- (d) means for modulating the damping coefficient of the viscous damper in response to the command signal to approximate the vibration isolation characteristics of a "sky hook" type damper.
An active vibration isolation system comprising:
- (A) means connectable to a payload and a base for generating a signal representative of the instantaneous ratio of the absolute velocity of said payload to the relative velocity between said payload and said base;
- and,
- (B) viscous damper means
- (i) including a servovalve through which an electro-rheological fluid can flow in response to a range of vibratory motions between said payload and said base,
- (ii) characterized by a variable instantaneous damping coefficient dependent on the viscosity of the electro-rheological fluid,
- (iii) for generating transmissibility characteristic substantially the same as a sky-hook type damper, and
- (C) and wherein said servovalve includes means for modulating the viscosity of the electro-rheological fluid in response to said generated signal and, thereby, modulating the variable damping coefficient of the viscous damper in response to said generated signal.
A method for reducing the transmission of vibratory motion between first and second elements by using a viscous damper mounted therebetween and supporting said first element comprising:
- (A) deriving a first signal representative of the velocity of relative motion between said first and second elements;
- (b) deriving a second signal representative of the absolute velocity of said first element;
- (c) generating a command signal as a function of the ratio of said second signal to said first signal;
- and
- (d) generating transmissibility characteristics substantially the same as those of a sky-hook type damper, including the step of modulating the damping coefficient of said viscous damper in response to said command signal.
A viscous damper for use with a substantially incompressible electro-rheological fluid, including a passive dissipation element comprising servovalve means for metering the flow of fluid therethrough and thereby providing damping pressure drops and resulting dissipation forces, said servovalve means comprising first and second conductive plate elements, substantially parallel to one another, in spaced relation and having opposing surfaces, and in contact with an insulative element disposed therebetween and defining means for directing fluid flow therethrough including first orifice means for directing fluid flow in a first direction through said first conductive element, second orifice means for directing fluid flow through said second conductive element, and third orifice means for directing fluid flow in a second different direction along said opposing surfaces, adjacent said insulative element, and between said first and second orifice means;
- and, wherein said insulative element defines a plurality of channels, each in fluid communication at one end thereof with one of the first orifice means and at the other end thereof in fluid communication with one of the second orifice means.
Dependencies are inferred from the claim text.