General Dynamics Advanced Technology Systems, Inc.

Other

USA as Represented by Secretary of the Navy

At+t Corp.

Bell Telephone Laboratories

Lucent Technologies Inc.

Sikorsky Aircraft Corporation

George Gustave Zipfel, Jr

Gregory Weston Terpay

Donald L White

John E Miesner

Stuart T Stanton

Victor G Mishkevich

Ka-Shu Lee

Thomas E Smith

William Edward Vanderbeck

William Arthur Welsh

Roger David Benning

Douglas Roy Browning

Michael S Torok

Christie Lewis Zipfel

Robert Zappulla

Thomas Edward Smith, Jr

Exemplary practice of the present invention provides a magnetostrictive actuator characterized by linear force output and uniform magnetic biasing. A center bias magnet drives flux through series magnetostrictive bars in opposite directions while surrounding drive coils apply flux in the same direction through the bars. The net response is substantially linear with respect to the drive coil current. A second parallel set of magnetostrictive bars completes the flux path and adds to the actuator output force. Flux leakage between the parallel bars is compensated by a ferromagnetic shunt or by a tapered magnet providing uniform flux density down the length of the magnetostrictive bars. The closed flux path allows magnetic shielding of the entire actuator, if desired.

Linear magnetostrictive actuator

A switching amplifier drives balanced piezoelectric or other capacitive or reactive loads with a minimum physical electronics volume, enabling a compact arrangement that can combine amplifier and transducer at the same physical location. Power supply current is minimized by using two or more transducers driven with phase-shifted signals, resulting in stored energy being cycled between the transducers rather than being carried over the power supply lines for storage in a power supply. Auxiliary power supply capacitors to store energy coming out of the load can thus be minimized. The modulation scheme puts the switching frequencies in common-mode while the baseband signals are differential mode. The common-mode switching frequency signals are blocked from the loads by a common-mode inductor. The common-mode inductor can be physically small as a result of the large baseband load currents being in differential mode. Low-volume load filters are made possible by the fact that they are not called upon to filter signals at the fundamental switching frequency but only at higher frequencies. The loads are biased independently of the baseband signals. The switching amplifier can drive balanced loads comprising two, three or more individual load elements.

Switching amplifier for driving reactive loads

A motor has a rotor for controlling a parameter of an instrumentality, such as a blade or a blade flap. The rotor is positioned about the drive shaft of the instrumentality and rotates at the same average angular velocity of the drive shaft. The instrumentality is controlled by applying to the instrumentality a physical displacement signal that is generated by the phase relationship of the rotor of the motor with respect to the angular position of the drive shaft. A plurality of permanent magnets proximate the periphery of the rotor cooperate with a plurality of stator polepieces and electromagnetic coils. The current flowing through the coils is reversed each time that the rotor advances by the angular space of one permanent magnetic pole. The strength and polarity of the current flowing through the coils controls the direction and displacement of the rotor with respect to a neutral phasing of the rotor with respect to the drive shaft.

Permanent magnet phase-control motor

A hub mounted actuation system for providing control of a portion of a rotor blade, such as a flap, on a rotorcraft. The rotor blade is attached to a rotor shaft that rotates with respect to an airframe. The hub mounted actuation system includes a stationary support mounted to the airframe and a rotary support attached to the rotor shaft for concomitant rotation therewith. At least one hub actuator rotates in combination with the rotor blade and includes a piston which is slidable within a housing. The piston and housing define a pressure chamber within the actuator which contains a fluid to be pressurized. A displacement control device is disposed between the stationary support and the rotary support for controlling movement of the piston within the housing. A linkage connects the hub actuator to the portion of the blade to be controlled. The linkage is adapted to displace the blade portion as a function of the movement of the piston within the housing.

Rotor hub mounted actuator for controlling a blade on a rotorcraft

In many uses of electrical motors, the interaction of a tool being powered, e.g., a milling machine, and the workpiece being worked on by the motor induces mechanical vibrations which adversely affect the functioning of the tool as well as inducing wear producing vibrations in the motor rotor shaft. Damping of such vibrations is achieved by deliberately inducing internal unbalanced forces on the motor rotor shaft for counteracting the externally induced vibrations. Such internal unbalanced forces are produced by the use of additional currents in the main stator coils for generating additional, unbalanced force generating magnetic fields. A mathematical analysis of the process is provided.

Unbalanced force generation in motors

A method and apparatus are provided for stabilizing at least one element of a mechanical system against echo-like responses to mechanical disturbances. One or more error signals are provided by sensing the motion of the system at one or more points. At least one adaptive filter is operated in response to the error signal or signals, and in response to at least one non-advanced reference signal that is directly related to some motion of the system. The adaptive filter produces a corrective signal for driving a mechanical actuator, thereby to apply to the element a stabilizing generalized force. By non-advanced is meant that there is a zero or negative time-delay between the presence of a given signal at the reference-sensing location and the arrival of the same, or a similar, signal at the error-sensing location. In particular embodiments of the invention, the reference-sensing location is the same as the error-sensing location.

Apparatus and method for adaptive suppression of vibrations in

Remote positioning to submicron accuracy is based on comparison of two interference gratings, the first of constant phase, and the second segmented. Positioning corresponds with equal segment-by-segment overlap of an image of one grating superimposed on the other.

High resolution remote position detection using segmented gratings

Through-the-lens alignment during deep UV lithographic processing in the manufacture of VLSI is accomplished without shifting the mask or wafer from the exposure position. Introduction and extraction of alignment light of actinic wavelength depends on beam routing due to diffraction from an interference grating. The path of alignment light is within the focusing system but does not impinge on the focused pattern.

Sub-micron through-the-lens positioning utilizing out of phase segmented

This disclosure describes a method for producing high-performance layered-element electrostrictive or piezoelectric actuators, and the resulting product. The process calls for steps that minimize decreases of the stack stiffness which usually characterize layered wafer actuators. These include making the wafers flat and parallel, using a referred wafer metalization process that does not affect wafer surface roughness, and using stock-bonding epoxies with viscosities which readily permit the bonding agent to 'wick' into the interface areas of the wafer/electrode stacks thereby to minimize the bond agent thickness.

Force generator for electrostrictive actuators

Disclosed is an electrodynamic moving coil actuator comprising one or more separate coils contained in interior spaces of a reactance mass. The coils are oriented in closely spaced parallel zones within the interior spaces. The spaces are formed and positioned to be outside of the static magnetic flux lines of the reactance mass. The static flux thus is substantially de-coupled from the dynamic magnetic field of the coil. Magnetic flux choke points are avoided, but at the same time, high volumetric efficiency is achieved. Each coil is attached to supports along its two long outer edges. The supports are connected to each other at their extremities by top and bottom plates which are connected by slide bars that also serve as tie rods. The reactance mass is mounted on the slide bars. The design is adapted to low frequency, high force applications such as active noise control automotive mufflers.

Reactance-mass actuator

A method of making flexible composite piezoelectric materials exhibiting hydrostatic response and having a stable response over time is given. A prepolymer material is combined with a piezoelectric material and polarized by applying an electric field while inducing an electric dipole in the piezoelectric material, typically by applying hydrostatic pressure or changing the temperature. To ensure stable response characteristics, the polymer material is chosen to have a shear modulus of less than 20 pounds per square inch. To help ensure good contact between the piezoelectric material and the polymer material, controlled shrinkage may be induced in the composite materials by heat or the removal of a volatile material. The prepolymer material desirably has an electrical resistivity greater than 10.sup.10 ohm/meters. Typical piezoelectric materials include lithium sulfate and tartaric acid. Typical polymer materials include RTV rubber, urethanes, and polybutadienes, and may be in the form of oligomers.

Method of making electromechanical transducers using improved flexible

In a channel electron multiplier device for detecting low level illumination optical image patterns, the output pattern of electrons is detected by an XY array of metal plates which are randomly accessed for readout by a corresponding row-column (XY) array of dual-gated insulated gate field effect transistors in an integrated circuit type of configuration. More specifically, each metal plate is located in the path of several (typically, ten or more) individual electron multiplier channels, in order to store the electrons emerging from these channels. The plates are all situated on the exposed surface of an insulating layer on a major surface of a semiconductor wafer. Each plate is connected through a different aperture in the insulating layer to a different localized source region of a different dual-gated insulated gate field effect transistor whose gate region is controlled by XY access control bus electrodes. These XY control bus electrodes are sandwiched in the insulating layer at levels in the insulator between the metal plates and the semiconductor wafer. Random XY access readout of the intensity of the electrons impinging on a given metal plate is obtained by energizing the crosspoint X and Y bus electrodes associated with that plate, and thereby the corresponding local intensity of the optical image portion, which produced the original photoelectrons in the channel multipliers associated with the accessed metal plate, can be determined.

Growing community of inventors

Summit, NJ, United States of America

George Gustave Zipfel, Jr