Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.