Abstract: A controllable magnetorheological (MR) damper having first, second and third portions is disclosed. The first and second portions have a translational degree of freedom therebetween, and the third portion has a rotational degree of freedom with respect to the first and second portions. The first and third portions are coupled via a translation-to-rotation converter, and the second and third portions are coupled via a magnetorheological (MR) fluid. A bearing is disposed between the first and second portions for supporting a side load therebetween, a magnetic field generator is in field communication with the magnetorheological fluid, and a signal path is in signal communication with the magnetic field generator.

Abstract: A controlled damper assembly includes a controlled-damper-assembly piston, a controlled-damper-assembly piston rod attached to the piston, an insulated wire, and an electrical connector. The insulated wire is positioned in the piston rod, has a first end operatively connected to the piston, and has a second end. The electrical connector has a first connection terminal electrically connected to the second end of the insulated wire and has a second connection terminal electrically connected to the piston rod. An example, without limitation, of a controlled damper assembly is a magnetorheological damper assembly.

Abstract: A controllable motion damper with a damping piston separating two damping chambers from each other in a damping cylinder. A damping valve is disposed in a connecting channel of the two damping chambers with the transmissivity of the damping valve for a damping fluid contained in the motion damper being controlled by a control device. Both damping chambers are filled with an electromagnetically uninfluenceable damping fluid. The control device includes a slide piston unit filled with a magnetorheological fluid. The slide piston unit includes a slide piston operatively coupled to the damping piston, wherein, through the intermediary of the magnetorheological fluid, the magnetorheological fluid is influenceable by controllable magnetic field generators with regard to its flow resistance with the slide piston acting on an actuator connected to the damping valve for controlling the movement of the damping piston.

Abstract: A roll control system for a vehicle is disclosed. The roll control system includes front and rear stabilizer bars, first and second magnetorheological actuators, and an electronic control system. The first magnetorheological actuator is disposed between the front stabilizer bar and the front suspension on one side of the vehicle, and a first droplink is disposed between the front stabilizer bar and the front suspension on the other side of the vehicle. The second magnetorheological actuator is disposed between the rear stabilizer bar and the rear suspension on one side of the vehicle, and a second droplink is disposed between the rear stabilizer bar and the rear suspension on the other side of the vehicle. The electronic control system is responsive to a vehicle operating characteristic and is in signal communication with the first and second magnetorheological actuators.

Abstract: A system that includes a magnetically actuated motion control device comprising a housing defining a cavity and including a slot therethrough. A movable member is located within the cavity and is movable relative to the housing. A magnetic field generator located on either the housing or the movable member causes the housing to press against the movable member to develop a friction force.

Abstract: A magnetorheological damper system comprising a reservoir in communication with a damper. The damper comprises a damper cylinder defining a damper chamber, wherein the damper chamber contains a magnetorheological fluid and a movable damper piston. The damper piston comprises at least two coil windings on the outer surface of the damper piston, wherein the damper piston is capable of generating a magnetic field between the damper piston and a wall of the damper cylinder. The reservoir comprises a reservoir cylinder defining a passageway, wherein the reservoir includes a magnetorheological electromagnet capable of generating a magnetic field between the magnetorheological piston and a wall of the passageway. The combination of the an MR reservoir and MR damper leads to a damping system capable of damping a wide range of extreme forces.

Abstract: An improved damping apparatus that utilizes a fluid having a viscosity that may be varied by the application of an electromagnetic field, such as a magnetorheological fluid or an electrorheological fluid, to provide the damping response. The damping apparatus includes a linear to rotary conversion mechanism which comprises a translatable member that is adapted for linear translation in a forward and a reverse direction and a rotatable member comprising a rotatable shaft that is rotatably coupled to the translatable member; wherein translation of the translatable member in one of the forward or the reverse directions produces a forward or a reverse rotation of the rotatable member and shaft, respectively.

Abstract: A controllable brake includes a rotor supported on one shaft end. The rotor is housed within a chamber containing a field controllable material which is acted upon by a magnetic field generator to change the rheology of the material and thereby impede movement of the rotor. The shaft is supported by two bearings which, in combination with the housing define a second housing chamber adapted to enclose means for monitoring and/or controlling the brake and in this way, an integrated, compact controllable brake is provided.

Abstract: Reversibly expandable energy absorbing assemblies that utilize an actively controlled and engineering material to reversibly change a shear stress or a flexural modulus property. The actively controlled and engineering materials include magnetorheological fluids, electrorheological fluids, magnetorheological elastomers, and electrorheological elastomers. Methods of operating the energy absorbing assemblies are also disclosed.

Abstract: A magnetorheological-fluid hydraulic mount includes a hydraulic-mount partition plate assembly, a hydraulic-mount decoupler, an electric coil, and a flexible membrane assembly. The partition plate assembly has first and second sides, has a non-magnetorheological-fluid first orifice, and has a magnetorheological-fluid second orifice. The first orifice has a first terminus positioned at the first side and a second terminus positioned at the second side. The second orifice has a first end positioned at the first side and has a second end positioned at the second side. The hydraulic-mount decoupler is operatively connected to the first orifice. The electric coil is disposed to magnetically influence the second orifice.

Abstract: A tunable vibration isolation device comprising a magneto-rheological elastomer (MRE), and methods of using such a device, are provided. By manipulating a magnetic field within the MRE the device's stiffness is controlled. The vibration isolator can be constructed to provide shock absorption in one, two and three dimensions. Coupling the tunable device to a sensor feedback and a control system provides fast and accurate vibration isolation and energy dissipation for shock events in a variety of applications.

Abstract: A magneto-rheological (MR) damper including a piston guided in a cylinder that is filled with a magneto-rheological fluid, its work volume being formed oblique relative to the piston axis between the piston and the cylinder.

Abstract: A MR fluid formulation based upon a silicone liquid vehicle thickened with a treated fumed metal oxide and doped with one or more chemicals having hydrogen-bonding capability for use with natural rubber mounts. The MR fluid is resistant to settling of the magnetizable particles upon contact of the fluid with natural rubber. In one exemplary embodiment, the doping chemical is one or a combination of propylene glycol and a bifunctional ethoxylated amine.

Abstract: A hydraulic mount is provided having a body with first and second fluid chambers and a decoupler subassembly interposed between to partially define the first and second fluid chambers. The decoupler subassembly comprises first and second flexible decoupler members operatively sealed together to form a third fluid chamber. The first and second chambers may be substantially filled with a magneto-rheological fluid. The third chamber may be filled with a standard hydraulic fluid, like glycol.

Abstract: A damping apparatus and method for a drillstring comprising a bit comprising providing to the drillstring a damping mechanism comprising magnetorheological fluid and generating an electromagnetic field affecting the magnetorheological fluid in response to changing ambient conditions encountered by the bit.

Abstract: A suspension damper including a tube and a damping piston assembly disposed within the tube and slidably mounted therein for reciprocal movement in the tube. The suspension damper also includes a piston rod extending through the tube and connected to the damping piston assembly, a rod guide assembly closing a bottom end of the tube, and a rebound cut-off disk and spring suspended in the tube between the rod guide assembly and the damping piston assembly and cooperating with the damping piston assembly to provide a rebound cut-off effect between the rebound cut-off disk and the damping piston assembly. The rebound cut-off disk and spring have specific gravities that are greater than the specific gravity of the fluid in the tube, such that the disk and the spring sink in the fluid.

Abstract: Method for determining a present coil temperature of a coil of a magnetorheological (MR) damper of an operating automotive vehicle, wherein the coil is powered by an output of a controller connected to the coil through a conductor. One step includes calculating a coil-plus-conductor resistance from the voltage and the current of the output of the controller when the controller applies a test current to the coil and the conductor. Another step includes calculating the present coil temperature using at least the coil-plus-conductor resistance and compensating for the resistance of the conductor.

Abstract: A tunable and reusable impact energy absorbing system and process includes a control structure comprising a sleeve having an outer surface fixedly attached to a chassis, a seal at each end of the sleeve, a magnetorheological fluid disposed between the seals, and a coil in proximity to the magnetorheological fluid, wherein the seal and the magnetorheological fluid are in sliding engagement with a support member, wherein the impact surface is fixedly attached to a support member. Varying the current to the coil alters the magnetic field upon the magnetorheological fluid, which can be used to tune the yield stress of the sliding engagement.

Abstract: In a controllable damping force shock absorber, a piston member connected to a piston rod is disposed in a cylinder in which a magnetic fluid is contained. A disc valve having an extension-stroke pressure-receiving portion and a compression-stroke pressure-receiving portion is provided in the piston member, and a pilot chamber is formed on a rear side of the disc valve. A coil is provided adjacent to passages communicated with the pilot chamber. By energizing the coil, a magnetic field that acts on the magnetic fluid flowing through the passages is generated, changing the viscosity of the magnetic fluid to control a damping force. A valve-opening pressure of the disc valve is controlled according to the pressure in the pilot chamber, such a way that the magnetic fluid exposed to the magnetic field can flow at a low flow rate, thus achieving low power consumption.

Abstract: An apparatus comprising a frame; a member movable relative to said frame; a damping device interconnected between the frame and the movable member; a controller for activating the damper to generate a damping condition at a predetermined member operating condition; and system for activating the damping device at a predetermined operating condition of the moving member during a loss of power to the apparatus. The damping device may comprise a field controllable damper that includes a volume of field controllable fluid, which may in turn comprise magnetorheological fluid for example. The rheology of the field controllable fluid is effected during the application of the field.

Abstract: A piston assembly for a magneto-rheological fluid damper is provided that exhibits good sealing properties at elevated temperatures. The piston assembly comprises a piston rod having an axial bore therethrough, a piston core coupled to a distal end of the piston rod for movement thererwith, an electrical terminal located on the piston core, a conductor, a sealing member and a support member. The conductor is coupled to the terminal to form an electrical connection and passes through the bore in the piston rod. The sealing member is adjacent to the distal end of the piston rod for preventing the penetration of fluid into the bore. The support member is located and sized to block an opening into the bore to prevent the sealing member from being forced through the opening when the piston assembly is subjected to pressure.

Abstract: The disclosed device is directed toward magneto-rheological fluid encasement device. The magneto-rheological fluid encasement device comprises a body having at least one containment element defining an interior and an exterior. A magneto-rheological fluid is disposed in the interior of the at least one containment element. At least one magnetic field is in operative communication with the magneto-rheological fluid.

Abstract: A damper in which magnetic particles are discouraged from settling irrespective of the kind of a magnetic fluid is provided. A damper is constituted of a vessel in which the magnetic fluid is accommodated and a slider (piston). As the piston, one that is made of a laminated body of a paramagnetic substance and a non-magnetic substance is used. When thus constituted, the magnetic particles stick to the piston. Accordingly, whatever magnetic fluid is used, the particles do not settle. The laminated body that is used as the piston has the non-magnetic substance at both ends thereof. When the laminated body is thus constituted, the magnetic particles sticks uniformly. When the laminated body has the magnetic substance at both ends, magnetic particles stick to both ends needle-like.

Abstract: Controlled oscillating damper, comprising: a housing (12) provided with a cavity (14), an oscillating element (18) moving sealingly within the cavity (14), in which the housing (12) and the oscillating element (18) have respective walls defining at least one chamber (44) filled with magneto-rheological or electro-rheological damping fluid, and at least one electrically controlled excitation device (46) equipped with at least one fluid passage (52) which a fluid flow gets through during the motion of the oscillating element (18). The excitation device (46) is stationary with respect to the housing (12) and is arranged so as to divide the damping chamber (44) into two sections of variable volume (44a, 44b) communicating one with the other through the passage (52).

Abstract: A magnetorheological damper system comprising a reservoir in communication with a damper. The damper comprises a damper cylinder defining a damper chamber, wherein the damper chamber contains a magnetorheological fluid and a movable damper piston. The damper piston comprises at least two coil windings on the outer surface of the damper piston, wherein the damper piston is capable of generating a magnetic field between the damper piston and a wall of the damper cylinder. The reservoir comprises a reservoir cylinder defining a passageway, wherein the reservoir includes a magnetorheological electromagnet capable of generating a magnetic field between the magnetorheological piston and a wall of the passageway. The combination of the an MR reservoir and MR damper leads to a damping system capable of damping a wide range of extreme forces.

Abstract: A shock and vibration isolation system for mounting equipment to a base wall uses a semi-active damper in parallel with a spring arrangement to provide optimum isolation with respect to both shock and vibration. The system comprises a load plate configured for attachment of the equipment thereto and a base plate configured for attachment to the base wall. The base plate is substantially parallel to the load plate with a spring arrangement disposed intermediate the load plate and the base plate. The spring arrangement engages the load plate and the base plate to bias the load plate and the base plate in a separated relationship. The system also comprises a damping arrangement disposed intermediate the load plate and the base plate. The damping arrangement is adapted for providing a selectively variable reaction force to the load plate and the base plate responsive to a relative displacement of the load plate with respect to the base plate.

Abstract: A variable spring member includes a containment housing defining an inner chamber with alternating layers of compressible medium and electro-reactive medium. Adjacent each layer of electro-reactive medium is a coil assembly controlled by a controller. A sealed plate disposed between alternating layers of compressible medium and electro-reactive medium disperses a load exerted on the variable spring member assembly and prevents intermixing of compressible medium with the electro-reactive medium. Actuation of the coil assembly changes physical characteristics and compressibility of the layer of electro-reactive medium to vary spring rate and stiffness.

Abstract: A torsion spring is equipped to provide a resilient force toward an opposite direction of a manipulation force of a driver's pedal and an magnetorheological damper is equipped to promptly actively attenuate the resilient force of the torsion spring and the manipulation force of the driver's pedal. Thereby, contributing to a wide control range of the reaction force of the pedal, an effective response, and a proper formation of hysteresis of the reaction force of the pedal.

Abstract: A magnetorheological fluid brake utilizing a positive displacement fluid pump adapted to pump a magnetorheological fluid through a viscosity regulator. The viscosity regulator is adapted to controllably vary the viscosity of the magnetorheological fluid, altering the pumping restriction against the fluid pump, resulting in variable resistance to pump shaft rotation relative to the pump housing. An electronic steering system for a work vehicle utilizing the illustrated magnetorheological brake as a resistance device to provide tactile feedback as a function of steering shaft rotational position.

Abstract: A motor-vehicle suspension having oscillating arms, in which one of the arms is formed by the casing of a rotational shock-absorber, wherein the oscillating piston of the shock-absorber is connected to the structure of the motor vehicle. Preferably, the casing of the rotational shock-absorber is also used for the anchorage of a respective end of a leaf spring, which constitutes the elastic element of the suspension.

Abstract: The invention disclosed is a magnetorheological fluid device offering vibration isolation and broad modulation range damping in a high load carrying and compact form. A cylindrically shaped flexure structure has a bottom cap attached to one end and a top cap attached to the other end. A piston comprising a toroidal displacement body, a central shaft, and intermediate connecting plate, attaches to the top cap. A fluid chamber surrounding and generally conforming to the shape of the toroidal displacement body, is attached to the bottom cap. Two bellows attaching between the piston connecting plate and top and bottom portions of the fluid chamber complete an enclosed volume around the toroidal displacement body and allow frictionless motion of the toroidal displacement body relative to the fluid chamber.

Abstract: A method and device for suspending a wheel axle from a vehicle includes a unitary flexible member coupled between the vehicle and the wheel axle and to an electronic control unit. The flexible member is formed of a material that changes shape in the presence of electrical signals having a varying signal strength. The electronic control unit, upon receiving various suspension related inputs, transmits the electrical signals having the varying signal strength to the unitary flexible member to change the shape thereof in order to vary the stiffness of the flexible member and thus control the suspension of the vehicle.

Abstract: Magnetorheological devices, including damping devices, rotary devices, and haptic systems constructed with said devices are disclosed. The devices contain dry magnetically-responsive particles, or MR fluids containing the magnetically responsive particles. The magnetically soft particles characterized by a single process yield population of atomized particles having a cumulative 10%, 50% and 90% by volume, fraction within specified size, i.e., D10 of from 2 up to and including a D10 of 5 ?m, a D50 8 ?m up to and including a D50 of 15 ?m, a D90 of 25 ?m up to and including a D90 of 40 ?m, and characterized by a least squares regression of log normal particles size against cumulative volume % fraction of greater than or equal to 0.77.

Abstract: A closing system for use with a magneto-rheological (MR) damper. The closing system provides lubrication for a piston rod without a need for periodic replenishment. According to an embodiment of the present invention, a lubrication chamber of the closing system utilizes a carrier fluid portion of MR fluid present in a fluid reservoir of the damper as lubricant for a piston rod guide and the piston rod. A seal retainer comprised of a porous material acts as a selective barrier to the micro-particles in the MR fluid in the fluid reservoir, allowing the MR carrier fluid portion to pass through the porous seal retainer to the lubrication chamber while restraining the micro-particles in the fluid reservoir. The seal retainer thus acts as a filter to segregate the abrasive particles of the MR fluid and allows the MR carrier fluid portion of the MR fluid to continuously replenish the lubrication chamber and lubrication passage to lubricate the piston rod guide and piston rod.

Abstract: A watercraft seat suspension includes a damper mounted between a watercraft seat and the watercraft hull. The damper includes an electrically actuated mechanism controlling fluid flow from a first chamber to a second chamber within the damper. A sensor senses motion of the seat relative to the hull. A control unit interpolates the sensor signal and develops an actuating signal controlling the electrically actuated mechanism. In one arrangement, the electrically actuated mechanism is a solenoid actuated by the actuating signal to effect one of two different damping modes. In another arrangement, the electrically actuated mechanism includes a conductor coil and flux ring generating a magnetic field proportional to the actuating signal to vary the viscosity of magneto-rheological fluid in the damper.

Abstract: A variable resistance cell and method provides a variable resistance response to a load factor, such as a load, a load rate, a strain, a strain rate, a pressure, or a deflection. A variable viscosity fluid is displacable between first and second chambers of an enclosure though an orifice in response to the load factor. The variable viscosity fluid has a viscosity that is variable corresponding to the load factor to vary an ability of the variable viscosity fluid to flow through the orifice. The variable viscosity fluid can be a shear stiffening material that increases in viscosity with an increase in a load factor applied to the shear stiffening material, a magneto rheologic fluid responsive to a magnetic field, or an electro rheologic fluid responsive to an electric field. The enclosure can be compressible between first and second positions.

Abstract: The invention provides a magnetorheological piston and damper assembly. The piston includes a piston body including at least one bypass port and an annular gap formed therein. The bypass port is in fluid communication with the annular gap. The bypass port includes a longitudinal portion extending substantially parallel to a piston longitudinal axis, and a bend portion extending substantially away from the longitudinal axis. The annular gap is spaced apart from the longitudinal portion and extends substantially parallel to the piston longitudinal axis. During operation, fluid flows through the bypass port and annular gap. The damper assembly includes a rod and a housing including the fluid carried therein. The piston is slidably carried in the housing and operably attached to the rod.

Abstract: A method controls the damper current of a damper of a motor vehicle. The damper is adjustable by an electrical current and the permissible change of the current per time interval is delimited by a limit.

Abstract: A controllable brake includes a rotor supported on one shaft end. The rotor is housed within a chamber containing a field controllable material which is acted upon by a magnetic field generator to change the rheology of the material and thereby impede movement of the rotor. The shaft is supported by two bearings which, in combination with the housing define a second housing chamber adapted to enclose means for monitoring and/or controlling the brake and in this way, an integrated, compact controllable brake is provided.

Abstract: An apparatus (10) for helping to protect an occupant (28) of a vehicle (12) includes a knee bolster (20). An energy absorbing device (80) is interposed between the knee bolster (20) and the vehicle (12). The device (80) includes a field responsive fluid (84) having a viscosity that varies in response to an energy field acting on the fluid. The device (80) also includes at least one passage (134) through which the fluid (84) flows upon movement of the knee bolster (20) relative to the vehicle (12). The device (80) further includes means (150) for varying the viscosity of the fluid (84) to vary the flow rate through the at least one passage (134) and thereby vary the resistance to movement of the knee bolster (20) relative to the vehicle (12).

Abstract: What is disclosed is a magneto-rheological (MR) damper including a piston guided in a cylinder that is filled with a magneto-rheological fluid, its work volume being formed oblique relative to the piston axis between the piston and the cylinder.

Abstract: A variable spring member includes a containment housing defining an inner chamber with alternating layers of compressible medium and electro-reactive medium. Adjacent each layer of electro-reactive medium is a coil assembly controlled by a controller. A sealed plate disposed between alternating layers of compressible medium and electro-reactive medium disperses a load exerted on the variable spring member assembly and prevents intermixing of compressible medium with the electro-reactive medium. Actuation of the coil assembly changes physical characteristics and compressibility of the layer of electro-reactive medium to vary spring rate and stiffness.

Abstract: There is provided a simplified loading device in which a permanent magnet is arranged between a moving element and a fixed element for holding the moving element, a magnetic fluid is disposed in a gap developed at some midpoint in a magnetic circuit in which the magnetic flux of the permanent magnet passes through the moving element, and a shearing force of the magnetic fluid produced by the magnetic flux of the permanent magnet is exerted on the moving element as a loading force. Thereby, a higher loading force can be generated and the device can be made smaller in size than in the case of the conventional friction or hysteresis brake.

Abstract: A magnetorheological damper system comprising a reservoir in communication with a damper. The damper comprises a damper cylinder defining a damper chamber, wherein the damper chamber contains a magnetorheological fluid and a movable damper piston. The damper piston comprises at least two coil windings on the outer surface of the damper piston, wherein the damper piston is capable of generating a magnetic field between the damper piston and a wall of the damper cylinder. The reservoir comprises a reservoir cylinder defining a passageway, wherein the reservoir includes a magnetorheological electromagnet capable of generating a magnetic field between the magnetorheological piston and a wall of the passageway. The combination of the an MR reservoir and MR damper leads to a damping system capable of damping a wide range of extreme forces.

Abstract: Disclosed is a brake apparatus using magnetic powder which includes first and second brackets faced to each other, a ring-shaped stator installed between the first and second brackets and having a coil therein, a ring-shaped brake fixed spaced apart from an inner circumference of the stator, a rotary shaft rotatably combined to an axial hole formed at a center of the second bracket, a rotator rotatably installed to the rotary shaft with its outer circumference being spaced apart from an inner circumference of the brake, and magnetic powder filled in a space between the inner circumference of the brake and the outer circumference of the rotator.

Abstract: A piston plate for use with a magneto-rheological (“MR”) fluid damper. The piston plate comprises an inner hub and outer rim. The hub has simple geometry and is made from easily machineable material, permitting it to be fabricated using low-cost processes. The rim, which is secured over the hub, is made from a high strength, ferrous metal. The rim may be heat treated for greater strength and reduced magnetic permeability. In one embodiment of the present invention, the rim may be made from powdered metal. A magnetic insulator may be included on an interior face of the piston plate to reduce magnetic coupling between the rim and a piston core in a piston assembly. In another embodiment of the present invention, the piston plate may be made as a single piece from compressed powdered metal.

Abstract: A closing system for use with a magneto-rheological (MR) damper. The closing system provides lubrication for a piston rod without a need for periodic replenishment. According to an embodiment of the present invention, a lubrication chamber of the closing system utilizes a carrier fluid portion of MR fluid present in a fluid reservoir of the damper as lubricant for a piston rod guide and the piston rod. A seal retainer comprised of a porous material acts as a selective barrier to the micro-particles in the MR fluid in the fluid reservoir, allowing the MR carrier fluid portion to pass through the porous seal retainer to the lubrication chamber while restraining the micro-particles in the fluid reservoir. The seal retainer thus acts as a filter to segregate the abrasive particles of the MR fluid and allows the MR carrier fluid portion of the MR fluid to continuously replenish the lubrication chamber and lubrication passage to lubricate the piston rod guide and piston rod.

Abstract: An impact absorber using an energy-absorbing, fluid-impregnated material consisting of a porous interconnected network of solid material forming edges and faces of cells, preferably an open-cell reticulated or partially closed-cell foam, or formed from fibers or other cellular solids. The matrix is impregnated with a field responsive fluid such as a magneto- or electro-rheological fluid, or with a shear-rate responsive fluid such as a dilatant (shear-thickening) fluid. The material is placed under compression during impact, and may be housed within a cylinder and compressed by a piston. The stiffness of the composite material consisting of a matrix filled with a field responsive fluid can be controlled by varying the field intensity and spatial gradients of the applied field to vary the rheological properties of the fluid.

Abstract: A magnetorheological piston includes a body having a substantially magnetically energizable passageway and a substantially magnetically non-energizable passageway. The substantially magnetically non-energizable passageway has a valveless passageway throat and has a flow cross-sectional area which has a minimum at the passageway throat and which is larger away from the passageway throat. A magnetorheological damper includes a cylinder and the above-described magnetorheological piston, wherein the piston is positioned in, and slideably engages, the cylinder.

Abstract: A rotary damper is disclosed. The rotary damper comprises a first and a second plurality of plates disposed within a housing. The first and second pluralities of plates are interleaved and are capable of moving relative to one another. A magnetorheological fluid contained within the housing resides in the interleave of the first and second plurality of plates. A magnetic flux generator drives a magnetic flux through the magnetorheological fluid in the interleave in a direction transverse to the orientation of the plates and is capable of varying the strength of the driven magnetic flux. The magnetic flux aligns the magnetic particles suspended in the magnetorheological fluid, increasing the shear strength of the magnetorheological fluid, which in turn resists motion between the first and second plurality of plates, acting as a damper.