Abstract: A controllable pneumatic apparatus including a pneumatic actuator coupled with a linear-acting brake including a field responsive medium. The pneumatic actuator has a housing with a gas cavity, a first piston slidably disposed in the gas cavity subdividing the gas cavity into first and second gas chambers, and an output member coupled to the first piston. The linear-acting controllable brake includes a medium containing cavity subdivided into a first and second chambers, and a second piston rigidly interconnected with, and longitudinally aligned with, the first piston. A passageway interconnects the first and the second chambers and a field responsive medium (e.g., a magnetic fluid) is contained in the passageway. A field generator produces a field to change a rheology of the medium and cause a braking force to be applied to the output member to control motion thereof. A preferable control method implements motion control based upon the kinetic energy and the braking force in the system.

Abstract: A controllable pneumatic actuator and motion control apparatus including a field responsive medium and control method therefor. The apparatus has a pneumatic actuator coupled to a rotary-acting brake such that a motion (e.g., a displacement, velocity or acceleration) of an output member may be precisely controlled. The pneumatic actuator has a housing with a piston moveable responsive to a pressure differentials and an output member coupled to the piston. The rotary-acting controllable brake includes a field responsive medium and a brake shaft coupled to the output member. Preferably, the apparatus includes a control system having a sensor for deriving motion signal and a motion control for processing the motion signal and providing a control signal to the brake.

Abstract: A controllable valve assembly (18) applicable in Magnetorheological (MR) fluid devices (20), such as MR mounts and MR dampers. The valve assembly (18) includes a valve body (32) having a magnetic circuit (40) contained therein which carries magnetic flux .phi., a controllable passageway (42) within the magnetic circuit (40), a MR (magnetically controlled) fluid (44) including soft-magnetic particles in a liquid carrier contained in the controllable passageway (42), a magnetic flux generator, such as a wound wire coil (46), generating magnetic flux .phi. which is directed through the MR fluid (44) in the controllable passageway (42) thereby generating "rheology" changes causing restriction in flow of MR fluid (44) therethrough.

Abstract: A deformable grip (10) for handheld implements such as writing pen (20) and other handheld equipment such as shaving instruments, medical instruments, sporting equipment, and similar articles, which is capable of being deformed in conformance with the user's s hands and fingers. The present grip (10) includes an elastomeric sleeve (40) filled with a magnetorheological (MR) fluid (60) and a magnetic field generator that acts upon such fluid to adjust grip deformability. In a preferred form of the invention, the implement body (32) or other equipment handle is configured to include a recessed cavity (35) wherein the (MR) fluid-filled sleeve (40) resides. A permanent magnet assembly (34) is disposed within the tubular sleeve (40) such that in an on-state of the present grip (10), the magnetic flux field extends radially to pass through the (MR) fluid (60) to instantaneously solidify it in a relatively nondeformable set condition in conformance with the user's anatomical contours.

Abstract: An adjustable valve including a passageway, a field responsive fluid within the passageway, and flow adjustment of the fluid through the passageway. In another aspect, the valve is in a vibration damper. In yet another aspect, the damper includes a body, a piston, first and second chambers, a damping valve, a piston rod, an auxiliary chamber, a passageway interconnecting to the auxiliary chamber, a field responsive fluid, a field responsive fluid valve for controlling flow to the auxiliary chamber, and pressurization means. Preferably included is a cavity partition having field responsive fluid disposed on one side and non-field responsive fluid disposed on the other. This allows a reduction of MR fluid allowing use of lighter-weight, less-expensive, hydraulic fluids for flow through the piston's damping valve. In another aspect, the damper includes mechanical adjustment device for manually adjusting a damping level.

Abstract: A controllable valve assembly (18) applicable in Magnetorheological (MR) fluid devices (20), such as MR mounts and MR dampers. The valve assembly (18) includes a valve body (32) having a magnetic circuit (40) contained therein which carries magnetic flux .PHI., a controllable passageway (42) within the magnetic circuit (40), a MR (magnetically controlled) fluid (44) including soft-magnetic particles in a liquid carrier contained in the controllable passageway (42), a magnetic flux generator, such as a wound wire coil (46), generating magnetic flux .PHI. which is directed through the MR fluid (44) in the controllable passageway (42) thereby generating "rheology" changes causing restriction in flow of MR fluid (44) therethrough.

Abstract: A controllable platform suspension system (20) for treadmills (18) and other platforms and devices therefor which exhibit controllability of the impact condition of the platform, such as a treadmill deck (36). In the treadmill application, user-selectable damping/stiffness is provided to simulate variable track conditions, such as pavement, rubber, grass, gravel, sand, and the like. The controllable suspension system (20) comprises spring mounts (40) or the like or a flexible deck (36) for allowing movement of the deck (36) relative to the frame (22) at a contact location (29) due to impact and a controllable device such as an Electrorheological (ER) device, Electrophoretic (EP) device, Electromechanical Hydraulic (Semi-Active) device, controllable mounting, or a Magnetorheological (MR) device, such as an MR brake (42a, 42a, 42b), MR damper (42d), or MR mount (42c, 42e, 42f) interconnecting between the frame (22) and platform (36) to provide the user-variable impact restraint.

Abstract: A magnetorheological fluid device which exhibits excursion (stroke or rotation) dependent resistance (force or torque) which is obtained passively. Linear and rotary embodiments are described. The devices described herein include various ways for passively varying magnetic circuit reluctance to accomplish the stroke or rotation dependent characteristic.

Abstract: A flexibly-mounted active vibration absorber (AVA) which has a secondary controllable mass M.sub.3. If the passive resonance of mass M.sub.2 of the tuned absorber is insufficient to control the input vibration, a secondary mass M.sub.3 is vibrated at a frequency, amplitude and phase sufficient to make up the deficiency in mass M.sub.2. Many embodiments are described which depict variations on the first spring used for flexibly mounting the AVA, the actuators used to drive the AVA, and the attachment features for attaching to a vibrating member. Further in another aspect, means for counterbalancing the moments produced by the AVA are described.

Abstract: A hybrid active-passive system (20) for reducing noise within a passenger compartment and vibration of a fuselage of a vehicle, such as an aircraft (turboprop, turbofan, or helicopter). The hybrid active-passive system (20) includes, in combination: an active acoustic producer such as a loudspeaker (35), Active Vibration Absorber (AVA) (34), or active absorber assembly (39) for producing antinoise within the compartment (42), and a passive resonant device, such as a passive Tuned Vibration Absorber (TVA) (36), or passive TVA assembly (37) for controlling vibration of the fuselage or structural supports interconnecting the disturbance source (e.g. power plants (26), propellers (28a), gearbox (57), main rotor (28m), tail rotor (28t)) and the fuselage wall (25).

Abstract: Actuators for active vibrational energy control systems which are frequency focused. The high-frequency cancellation function is decoupled from the low-frequency cancellation function to enable the size, force, number and placement of the actuators to be optimized. A hybrid system employing structural actuators to cancel low-frequency vibrations and speakers to cancel higher-frequency vibrations is also taught.

Abstract: A method and system/apparatus implementing a non-model based Decentralized Feedforward Adaptive Algorithm (DFAA) for active vibration control of an actively-driven element, such as an Active Vibration Absorber (AVA) (24). The AVA (24)preferably includes an inertial tuning mass (42) and a voice coil assembly (46) and is contained in an active vibration control system (20) wherein the method and system/apparatus reduce vibration of a vibrating member (22) at an attachment point (26) by receiving an error signal from an error sensor (28) such as an accelerometer and a reference signal from a tachometer (32) or accelerometer (34), where the reference signal is correlated to, or indicative of the frequency content of, a primary vibration source (36) and calculating an updated output signal via an electronic controller (39) using the non-model based DFAA to dynamically drive the actively-driven element, such as AVA (24).

Abstract: An active system for controlling vibration or sound. The system includes a method for limiting the output gain G from a gradient descent algorithm, such as an LMS algorithm, according to the relationship ##EQU1## and reducing one of first and second filter weights W.sub.1 and W.sub.0 such that G.ltoreq.G.sub.max ensuring the output canceling signal is never saturated. This eliminates the square wave shape which may impart unwanted harmonics or resonances to the dynamic system. In another aspect, the system eliminates drift of the output devices toward saturation when situations are encountered such as singularities in the quadratic performance surface. This is accomplished by applying leakage factor r(k) to a function f(k) at or near a predetermined limit to avoid saturation of the output device. The function f(k) can be the gain G or the weights W(k). Another aspect is to provide a constant, optimum, and stable adaptation rate in an LMS system by providing an optimum adaptation coefficient .mu..sub.

Abstract: A non-active regenerative system (20) which regenerates energy by taking energy from relative motion of members (22) and (24) and using it later to accomplish overall improved performance and eliminates the need for an active source to provide assisting forces. The non-active regenerative system (20) includes an energy transformer element (26) interconnecting a first member (22) and second member (24) which converts relative motion to an energy in storable form, and an energy management element (30) which channels the flow of energy to and from an energy storage element (32) to produce assisting forces. The energy management element (30)is commanded by a controller (36) which is responsive sensors (34a, 34b, 34c, and 34d) which provide signals indicative of the system condition. Power is supplied to the energy management (30), sensors (34a, 34b, 34c, and 34d), and controller (36), only if required, by power source (40). However, no active power source is needed to drive the transformer element (26).

Abstract: An active noise and vibration cancellation system with broadband control capability. A broadband disturbance signal detector positioned within a closed compartment such as an aircraft cabin or vehicle passenger compartment provides a signal representative of the frequency spectrum and corresponding relative magnitude of a broadband signal emanating from a vibrational energy source to a controller. The controller receives the broadband disturbance signal as well as error signals from error sensors which, by virtue of adaptive filters within the controller, enhance the cancellation capability of the control signals produced by one or more actuators positioned within the compartment.

Abstract: A method and apparatus for reducing suspension end-stop collisions is disclosed. The method and apparatus controls the operation of an isolation system having an adjustable damper assembly interconnecting relatively movable members to attenuate the transmission of forces therebetween, in which relative movement of the members is restricted beyond a certain limit by one or more end stops. Sensors monitor the conditions of the system such as the displacement, velocity and acceleration of the members. Damper command signals are provided to the damper assembly to adjust the damping characteristics of the assembly, as determined by the data, in accordance with both a primary control policy and an override control policy. The override control policy alters the damper command signals as necessary to increase the damping characteristics of the damper assembly at times when the isolation system is likely to meet or exceed the end stops in order to minimize the incidence of end-stop collisions.

Abstract: A fluid mount with the capability of actively controlling the amount of vibrational energy transmitted thereacross. An actuator is provided in series or in parallel with the inertia track passageway of a double pumper isolation mount to permit the dynamic stiffness of the mount to be varied so as to control the amount of vibrational energy transmitted in a desired manner. A control system for permitting frequency-shaped force feedback control of the device is also disclosed. Utilization of the device as a tuned absorber is also described.

Abstract: The transducer is directly associated with a fluid-type damper having a cover member and a cylinder member that undergo telescopic movement relative to each other in response to relative movement between vehicle components interconnected by the damper. In the preferred embodiments, both a passive electrical coil and a magnet are mounted upon the cover member, in fixed relationship to each other. Relative axial telescoping movement between the cover member and the cylinder member of the damper changes the flux field of the magnet and induces in the coil a voltage which is proportional to the relative velocity between the damper members and thus between the vehicle components interconnected by the damper. In an alternative embodiment, the magnet is mounted upon an end portion of the damper cylinder member.