Abstract: An apparatus and method for control of stiffness and damping in a flexible composite structure by the application of an electric field to an electrophoretic fluid forming part of the structure. The structure includes spaced, parallel, flexible layers of material which include confronting electrodes. The electrophoretic fluid is capable of separating into particle-rich and particle-deficient phases by electrophoresis and operates in surface contact with the layers. An electrically nonconductive material having raised surface areas and spaces between the surface areas is associated with one or more of the layers. When a voltage is applied between the layers in a first direction, the particle-rich phase of the fluid collects on one of the layers and also makes contact with the spaces and the raised surface areas of the material associated with the other layer thereby engaging or locking the layers together to increase the shear strength of the layers and thus the complex stiffness of the structure.

Abstract: An electrophoretic fluid torque transmission apparatus and method in which cooperable electrodes are connected respectively to drive and driven elements. An electrophoretic fluid capable of separating into particle-rich and particle-deficient phases by electrophoresis operates in surface contact with the electrodes. An electrically non-conductive material having raised surface areas and spaces between the surface areas is associated with one or more of the electrodes. When a voltage is applied between the electrodes in a first direction, the particle-rich phase of the fluid collects on one of the electrodes and also makes contact with the spaces and the raised surface areas of the material associated with the other electrode thereby engaging or locking the electrodes together and transmitting force between the elements.

Abstract: A vibration isolator including an electrorheological fluid filled partition assembly for providing variable dynamic stiffness characteristics. The partition assembly separates the variable volume fluid chambers of the isolator and includes movable electrode elements which define therebetween a chamber containing an electrorheological fluid. A fixed electrode is positioned between the movable electrode elements and separates the chamber into upper and lower portions. A plurality of openings extend through the fixed electrode allowing for passage of the electrorheological fluid between the portions in response to movement of the movable electrode elements. The yield stress developed in the electrorheological fluid by application of an electric field constrains movement of the movable electrode elements in response to input excitations thereby providing the isolator with a selectable dynamic stiffness.

Abstract: An electrophoretic fluid damper in which cooperable electrodes are slidably disposed one within the other and are connected respectively to relatively movable members. An electrophoretic fluid capable of separating into particle-rich and particle-deficient phases by electrophoresis operates in surface contact with the electrodes. An electrically nonconductive material having raised surface areas and spaces between the surface areas is associated with one of the electrodes. When a voltage is applied between the electrodes in a first direction, the particle-rich phase of the fluid collects on one of the electrodes and also makes contact with the spaces and the raised surface areas of the material associated with the other electrode thereby engaging or locking the electrodes together and transmitting force between the members.

Abstract: An apparatus for controlling the transmission of torque between drive elements using an electroactive fluid which is sealed within an enclosed chamber. A housing defines the chamber and includes at least one end defining an opening. Spaced electrodes are provided in the chamber in contact with the fluid and are respectively connected to the drive elements. A controllable power source applies a variable electric field to the fluid such that force is transmitted between the electrodes by the fluid according to the strength of the field. A shaft connects one of the electrodes to one of the elements and extends through the opening. A ferrofluid seal assembly prevents leakage of the fluid from the chamber through the opening. The assembly defines with the shaft an annular space in communication with the fluid. A magnetic circuit is provided in the assembly by a permanent magnet for applying a concentrated magnetic field in one or more regions across the annular space.

Abstract: The bidirectional valve assembly provides for selection of retraction and extension damping characteristics which can accommodate relatively large separation of damping curves. Two cooperable valve discs or ring members are provided which function in unison to resist fluid flow in a first fluid flow direction, while a single one of the valve ring members functions primarily to resist fluid flow in the other direction. In a first embodiment, one of the two cooperable valve ring members comprises a compliant retainer or fulcrum against which the other valve ring member moves in unison therewith to produce relatively low damping in retraction. The other valve ring member moves alone in extension to produce relatively high damping. In an alternative embodiment, the two cooperable valve ring members are superimposed and move in unison during extension, as dictated by their combined stiffness.

Abstract: The fluid inertia mount of the like has an inertia track with an adjustable fluid path length located between variable volume fluid chambers of the mount. By adjusting the fluid path length of the inertia track the mount may be dynamically tuned continuously between a range of frequencies in a manner to provide a low stiffness notch for isolating input excitations that produce undesirable vehicle vibrations. A tuning plate assembly adjustably locates an opening of the inertia track in a desired location along the length thereof betwene extreme positions in which the fluid path length is relatively long and relatively short.

Abstract: An improved method and apparatus is provided for estimation of absolute velocity in active or semi-active suspension systems. A controller produces a signal estimate of absolute velocity which can be implemented by a control algorithm to attenuate motion between spaced members, such as in vehicular suspension systems. The controller performs time integration of an accelerometer input signal by an analog integrator means comprising a first-order low-pass filter. A digital feedback or offset means is utilized to stabilize the signal and constrain the constant and relatively low frequency components of the analog integrated signal about an oscillatory voltage range. A digital filter means receives the stable signal and removes selected constant and low frequency components of the signal to produce a signal indicative of absolute velocities for a frequency range of interest further stabilized about a select mid-range voltage value.

Abstract: Controllable electrorheological fluid composite structure elements incorporate electrorheological fluids as a structural component between opposing fluid containment layers to form at least a portion of any variety of extended mechanical systems such as plates, panels, beams and bars or structures including these elements. The electrorheological fluid is operatively contained in a region between the containment layers and has complex shear and tensile modulus properties which vary with the electric field applied thereto. A variable power source is utilized to create an electric potential between the layers of the structure element to create the electric field. An alternative power source may include the use of a piezoelectric material layer. In order to maintain the insulation and spacing between the containment layers, a fabric or separating layer having an open mesh is provided which permits the transportation of electrorheological fluid in the region between the layers.

Abstract: An improved isolation system for time responsive attenuation control led electromechanical valve assembly comprising the piston of motion between spaced members is provided having a remotely actuator of a fluid damper for generating motion attenuating forces. The piston valve assembly employs a moving coil valve slider moveable between first and second positions to generate damper forces independently of the fluid pressure differential between opposing fluid chambers. Direct flow passages extend through the piston valve assembly between the opposing chambers. In the first position of the valve slider, fluid flow is substantially permitted through the direct flow passages to provide a substantially nonresistant damper force. In the second position, the valve slider intersects internal porting portions of the direct flow passages to substantially restrict fluid flow therethrough and provide a resistant damper force.

Abstract: An electrorheological fluid torque transmission and conversion system provides for variable control of torque in clutch and brake applications. Communication of mechanical energy between the drive elements is accomplished by magnetic coupling to eliminate the need for a dynamic fluid seal for interface of moving parts to the interior portion of the electrorheological fluid containment chamber. Permanent magnets are associated respectively with each of a first member and a second member which are magnetically coupled through a surface with low magnetic permeability such that the first member and second members rotate in unison. A variety of permanent arrangements may be utilized. Further, the drive element internal to the electrorheological fluid chamber may be both mechanically and electrically decoupled. A floating electrode may be capacitively coupled through the fluid to the power supply. Also provided are inner and outer conductive plates are provided for increased fluid surface contact area.

Abstract: The mount has variable volume fluid chambers interconnected by fluid passageways and containing electrorheological fluid. Valves are arranged in series with a plurality of the passageways. Each valve has a flow area greater than that of the passageway in series therewith. Energization of a valve generates an electrical field effective to so increase the apparent viscosity of the fluid within the valve as to prevent fluid flow through the passageway in series with it. Selective energization of the valves, by suitable controls associated therewith, varies the frequencies at which fluid inertia forces cause the mount to undergo abrupt changes in dynamic stiffness. The valves may be located upon opposite sides of a central mount section through which the chamber connecting passages extend. Electrode elements of the valves are preferably so shaped as to minimize fluid drag and electrical concentration.