Abstract: A magnetostrictive linear actuator, responsive to an external signal, including a housing assembly that encloses a magnetostrictive force train assembly, an excitation means disposed on a component of one assembly, as well as a thermal compensation means disposed on a component of the complementary assembly, and a controller means responsive to the external signal which provides a heat control signal in dependence on the magnitude of the controller signal such that the thermal expansion of the assembly heated by the excitation means will be compensated by a matching thermal expansion induced in the complementary assembly.

Abstract: A bearing arrangement for rotatably supporting a generally cylindrical journal having an outer circumferential surface exhibiting out-of-round deviations superimposed on a perfect cylinder that is centered on a longitudinal axis, with the journal acting on the bearing arrangement with a basic radial action force aimed along a reference half-plane extending in a predetermined radial direction from the longitudinal axis, includes a pair of bearing pads situated at respective contact locations that are spaced in opposite circumferential directions from the reference half-plane. Each of the bearing pads extends substantially over the entire length, but at most only over a small fraction of the circumference, of the outer circumferential surface, such that the bearing pads are at most in a very limited area contact with the outer circumferential surface when the journal is supported thereon.

Abstract: A commutator arrangement includes a commutator member rotatably mounted on a support and including a plurality of circumferentially adjacent contact pads that are mechanically connected with one another and electrically separated from each other by respective intervening gaps, and a number of commutator brushes that are mounted on the support for only substantially radial movements toward and away from the commutator member and are biased toward the latter to establish contact between their respective contact surfaces and those of the pads. The lateral edges bounding one kind of these contact surfaces circumferentially deviate from those delimiting the other contact surface kind over at least a part of their courses such that different portions of such lateral edges are juxtaposed with their counterparts at different times during the relative rotation of the commutator member.

Abstract: An arrangement for chopping a collimated beam of light traveling in an initial path, includes a flexible mirror which reflects substantially all of the light from the initial path into an auxiliary path in a first configuration thereof. The flexible mirror is deformed by a magnetodistortive actuator from its first configuration to a second configuration in which it disperses the light reaching it in such a manner that all but a minute fraction of the dispersed light propagates outside the path. Further propagation of the light that is reflected by the flexible mirror to the outside of the auxiliary path along the auxiliary path is blocked by an aperture plate having an apeture through which all of the light reflected by the flexible mirror passes when the flexible mirror has its first configuration.

Abstract: An arrangement for detecting the passage of living beings into and out of a surveillance region includes optics which concentrate thermal radiation energy from the surveillance region into a detection zone where an active area of a pyroelectric detector is situated and converts the thermal radiation energy received thereby into an electrical signal. An evaluating device evaluates the electrical signal of the detector to provide an indication of either the entry of a living being from the outside into, or the exit of a person from, the surveillance region from a change in the total thermal radiation energy received by the active area from the surveillance region. The optics may incorporate a mask which prevents thermal radiation from the outside of the surveillance region from reaching the active area of the detector.

Abstract: A brushless DC motor employs a set of coils positioned around the motor axis to respond to an aximuthal pattern of changing eddy current sensitivity. Rf voltage is frequency-multiplexed on the motor power leads at a frequency that does not affect motor operation. Rf voltage measurement circuits located remotely from the motor respond to the changing coil impedance to generate signals representing the azimuthal position of the motor rotor, that control a set of commutation circuits.

Abstract: A linear magnetostrictive actuator with feedback compensation including a force train that has at least one magnetostrictive element, an excitation component disposed on or within the actuator, a feedback apparatus whose output signal is proportional to the magnetic induction within the magnetostrictive element, and actuator control circuitry for providing the difference signal resultant between the feedback output signal and the external signal, such that positional displacement error is compensated by closed loop operation of the actuator.

Abstract: A linear extension piezoelectric actuator comprises a displacement generator having a plurality of discrete groups of piezoelectric material segments disposed coaxially along the extension axis of the actuator, each group being energized separately by voltage excitation signals from an external source to provide a corresponding one of a plurality of extension increments which in summation provide the total range of extension along the extension axis.

Abstract: Microwave signals are injected at one end of a slotted waveguide containing a shorting stub which is moved along the length of the waveguide. The distance to the shorting stub is determined from the comparative phase characteristics of the injected signals reflected back from the shorting stub.

Abstract: A method of mitigating 2.pi.N phase ambiguity in an adaptive optics control system is disclosed wherein the radiation sensed by a detector within a feedback loop is passed through an aperture having a variable diameter. The turn-on of the adaptive optics control system is initiated with the aperture in an open position to transmit radiation from all actuator zones onto the detector resulting in a convergence free of the 2.pi.N phase ambiguity. The diameter of the aperture is then reduced slowly compared to the bandwidth of the control system to converge to a near diffraction limited output beam at the aperture.

Abstract: A method and system for automatically aligning a high power laser. The high ower laser train includes an unstable resonator cavity and two turning mirrors to direct the pointing of the output laser beam. The autoalignment system is designed to perform two alignment tasks, the maintenance of output beam pointing stability and the establishment of resonator cavity mode control, by precisely adjusting the orientation of the end mirrors of the resonator cavity and the two turning mirrors. A HeNe laser, located at the output end of the high power laser train, propagates an alignment beam back along the laser train, parallel to the high power laser train. The alignment beam is divided into two separate alignment beams by means of a mirror splitter. One of the beams is directed on an optical alignment path which includes the two turning mirrors and is delimited by two null position detectors, one on an end mirror of the resonator cavity and one at the output end of the high power laser train.