Abstract: The invention relates, in particular, to an instrument for measuring length, comprising an inductive sensor comprising an elongate body and a tip that is movable along a longitudinal axis. The body contains windings and defines a first cavity receiving a magnetic core. The instrument further comprises a casing which extends the body along the longitudinal axis, and which defines, together with the body, a second sealed cavity containing the tip. The capacity of the casing to resiliently deform along the longitudinal axis is greater than the capacity of said casing to resiliently deform along axes that are orthogonal to said longitudinal axis.

Abstract: An encoder includes a detector, a first position data calculator, a first data converter, an approximation device and a third position data calculator. The first data converter is configured to convert a first position data calculated by the first position data calculator into second position data whose second width in bits is longer than a first width in bits of the first position data. The approximation device is configured to calculate an approximation function that derives position data when timing data is input, based on a plurality of the second position data converted by the first data converter at a plurality of successive sampling timings, respectively. The third position data calculator is configured to calculate third position data indicating a position of a detection target at an output timing, based on the approximation function calculated by the approximation device.

Abstract: A method of testing a transformer prior to installation in a high-pressure environment wherein the transformer comprises a transformer core comprising a stack of a plurality laminations, is provided. The method comprises applying a mechanical compression force to the stack, the force being at least equivalent to the ambient pressure of the high-pressure environment; and testing the electrical efficiency of the transformer.

Abstract: A measurement device is provided. The measurement device comprises a ring-shaped base and multiple sensing units and a plurality of coils. The sensing units are disposed on and protruded from the inner circumferential surface of the ring-shaped base. Each sensing unit comprises a circumferential groove and an axial groove. The axial groove is connected to the circumferential groove. Each coil is surrounded within the circumferential groove and extended along the axial groove.

Abstract: A method includes measuring a first voltage (VA) across a first sensing coil of a linear variable differential transformer (LVDT) and measuring a second voltage (VB) across a second sensing coil of the LVDT. The method also includes signaling a core fallout condition in response to (i) determining that a ratio of VA and VB is within a specified range of a value of one and (ii) determining that a sum of VA and VB is less than a sum of VA0 and VB0 by more than a specified amount. VA0 and VB0 are minimum voltages across the first and second sensing coils of the LVDT, respectively, when a core of the LVDT is in the LVDT.

Abstract: A single housing with a non-ferromagnetic piezo-driven flexure has primary and secondary coil forms of different diameters, one coaxially inside the other, integrated in the flexure. The cylinders defining the planes of the primary and secondaries do not spatially overlap. The secondary coil forms may be wound in opposite directions and wired to provide a transformer device. Movement of the primary relative to the secondaries in the direction of the central axis of the coils can be differentially detected with high precision.

Abstract: A resolver according to the invention includes a stator provided with a plurality of teeth, and first to third phase output coils wound around the teeth. When voltages induced in the first to third phase output coils change based on rotation of a rotor, voltage signals corresponding to an electrical angle of the rotor are output from the output coils. One of the first to third phase output coils is wound around each of the teeth. With respect to each of the phases, the distribution of the numbers of turns of each phase output coils, among the first to third phase output coils, is set to a sinusoidal distribution with respect to the electrical angle of the rotor.

Abstract: Flow rate control valve includes: a target probe formed of a magnetically-responsive substance and mounted to one end of a spool; a sensor housing mounted to the one end of the sleeve and having a cylinder section defining an inner space to permit entry therein of the target probe; and first and second coils provided around the cylinder section and axially spaced from each other by a predetermined distance. The probe is constructed so that magnetic response of the coils gradually varies in one direction in response to a linear position of the target probe. The first coil responds to the target probe, while the second coil does not respond to the target probe. Impedance of the first coil varies with a linear position of the probe (31), and the linear position of the probe is detected through differential synthesis performed between outputs of the first and second coils.

Abstract: A displacement sensor includes a primary coil (2), secondary coils (4a, 4b), and a movable magnetic core (6) movable with displacement of an object to be measured to cause voltages generated in the secondary coils (4a, 4b) to vary. The secondary coils (4a, 4b) are differentially interconnected. A polyphase signal generating unit (10) generates two-phase component signals having different phases, from a differentially combined output voltage of the secondary coils (4a, 4b). Full-wave rectifying units (16, 18) rectify the polyphase component signals, the rectified polyphase component signals are combined in a combiner (22), and the combiner output is applied to a low-pass filter (24).

Abstract: A control system for use in safety critical human/machine control interfaces is described, more particularly a joystick type control system and particularly a joystick type control system utilizing magnetic positional sensing. The control system provides a control input device having a movable magnet, a pole-piece frame arrangement positioned about the magnet, at least three magnetic flux sensors being positioned in said pole-piece frame arrangement and a monitoring arrangement for monitoring the output signal of each of said at least three sensors.

Abstract: Disclosed are devices, systems, assemblies, couplers, and other implementations, including a coupler that includes a first coupling element matingly engaged to a second coupling element, each of the first and second coupling elements including a plate defining an opening, a projection extending from a first surface of the plate, and a socket extending from a second surface of the plate and configured to receive a rotatable member. The projection of the first coupling element is received in the opening of the plate of the second coupling element, and the projection of the second coupling element is received in the opening of the plate of the first coupling element. The matingly engaged coupling elements are configured to rotate in response to rotation of a first rotatable member of a first device received in the socket of the first coupling element.

Abstract: A single housing with a non-ferromagnetic piezo-driven flexure has primary and secondary coil forms of different diameters, one coaxially inside the other, integrated in the flexure. The cylinders defining the planes of the primary and secondaries do not spatially overlap. The secondary coil forms may be wound in opposite directions and wired to provide a transformer device. Movement of the primary relative to the secondaries in the direction of the central axis of the coils can be differentially detected with high precision.

Abstract: A three-wire transformer position sensor is provided that includes an excitation coil and an output coil. The excitation coil is adapted to be electrically excited with an excitation signal, and has a first end and a second end. The output coil includes a first coil and a second coil and is inductively coupled to the excitation coil upon electrical excitation thereof the excitation coil. The first end of the first coil is electrically connected to the second end of the second coil and to the second end of the excitation coil, and the second end of the first coil is electrically connected to the first end of the second coil. The output coil is configured, when it is balanced and the excitation coil is being electrically excited, to supply a null output signal.

Abstract: A position sensor for the inductive detection of a position of a first component comprising a reference coil with respect to a second component comprising a reference body. A control and processing unit of the position sensor is coupled to the reference coil and is designed for issuing an output signal generating a current impulse in the reference coil. In addition, the control and processing unit is designed for evaluation of an oscillation generated by the current impulse in the reference coil as an input signal indicating the position of the reference body.

Abstract: A system for position sensing includes an incremental track including a plurality of sectors and a measurement subsystem. The measurement subsystem includes at least two differential read-heads each having at least one primary coil and at least two differential secondary coils, the at least two differential secondary coils of one of the at least two differential read-heads configured to generate output signals having their amplitudes modulated by the sectors of the incremental track and the at least two differential secondary coils of the other of said two differential read-heads configured to generate output signals having their amplitudes modulated by the sectors of the incremental track.

Abstract: A variable reluctance angle sensor includes a stator, a rotor, and a computation section. The stator includes a core member having teeth, which are arranged in a circumferential direction, and excitation coils, which are respectively wound about the teeth such that magnetic poles of the teeth have different polarities alternately in the circumferential direction. An input voltage is supplied to the excitation coils. The rotor radially faces the teeth of the stator. The rotor has a shape such that gap permeance with respect to the stator changes in a sinusoidal fashion in accordance with the rotational angle of the rotor. The computation section obtains output voltages of two or more phases having different phases based on the voltages of the excitation coils, and detects the rotational angle of the rotor based on the output voltages.

Abstract: Techniques for coupling with devices that convert displacements into differential voltages and improve the sensitivity of such devices. The disclosed system improves the accuracy and resolution of a transducers such as an LVDT by converting certain parts of the circuit to a digital circuit. One embodiment uses a processor, although other digital processing circuitry may also be used.

Abstract: An angle detecting apparatus includes a rotor fixed to a rotating shaft, a pair of magnetic sensors arranged close to the outer periphery of the rotor so as to have a difference in angle (?/2) with respect to the center of rotation of the rotor, a differential operational circuit performing differential operation on detection signals output by the magnetic sensors to output a differential signal, and the angle calculating circuit calculating the angle of rotation of the rotating shaft based on the differential signal. The planar shape of the rotor is such that the sum of the distances between the center of rotation and the respective two points where two straight lines crossing at the center of rotation at a crossing angle of (?/2) cross the outer periphery of the rotor is constant, and the planar shape is symmetric with respect to a straight line passing through the center of rotation.

Abstract: A multi-pole variable reluctance resolver is balanced wired and driven by 180 degree differential signals. Capacitive passive elements may be serially added to the resolver to minimize magnetic interference and cancel flux between poles of the same polarity and orthogonal poles, as well as minimize the effect of input driving signal distortion. Symmetric networks of resistive and capacitive elements may also be added to the resolver to overcome noise sensitivity associated with balanced wired resolvers.

Abstract: A transformer-less, solid-state pressure transducer assembly having significantly better characteristics than the electro-mechanical assemblies of the prior art. The pressure transducer assembly of the present invention achieves the many of the same functions as transducer assemblies of the prior art having transformers, however the pressure transducer assembly of the present invention is smaller in size and weight, cost less to manufacture, and has increased reliability.

Abstract: The invention relates to a method for analysis of magnetic fields or signals used for the determination of the position of an object, wherein two temporally to each other shifted magnetic signals or fields are generated by two conductors arranged at least in part or completely separated from each other. The magnetic fields generated by the conductors are consecutively being captured by at least one and preferably three sensors arranged orthogonally to each other and determining from the captured signals information for determining the position of the object carrying the sensors relative to the conductors.

Abstract: An apparatus including a controller, a transport in communication with the controller having a movable portion and a transport path and a multi-dimensional position measurement device in communication with the controller, the multi-dimensional position measurement device including a plurality of transformers and at least one element attached to the movable portion, wherein the multi-dimensional position measurement device is configured so that a circuit is completed in at least one plurality of transformers as the at least one element passes proximate to the at least one of the plurality of transformers and the controller is configured to calculate a multi-dimensional position of the movable object based on an output of the at least one of the plurality of transformers, wherein the multi-dimensional position includes at least a gap between the movable portion and the plurality of transformers.

Abstract: A half-bridge variable differential transformer position sensing system that includes a transducer having a stator with an inductive coil having a center tap configured to provide an output signal. The transducer also has an armature with a magnetically permeable core configured to move within the inductive coil, such that movement of the magnetically permeable core causes a change in the output signal. The position sensing system includes a first circuit configured to provide an excitation signal at one terminal of the inductive coil. The system includes no more than three electrical interface wires, and a microcontroller configured to calculate the degree of change in the position of the magnetically permeable core, and is configured to correct for variations in the voltage of the output signal due to the temperature of the transducer and due to non-linear effects on the output signal caused by movement of the magnetically permeable core.

Abstract: A position detecting system for a differential movement system which moves a first surface and a second surface from a fixed surface includes an actuation system to move the second surface relative to the first surface and to allow the second surface to move with the first surface; a sensor connected to the actuation system to detect a parameter of the actuation system related to an expected amount of movement of the second surface to determine the expected amount of movement of the second surface; and a sensor system connected to the second surface and the fixed surface to detect the amount of actual movement of the second surface.

Abstract: A device for providing displacement information includes a housing holding a displacement sensor. The displacement sensor includes a coil and a captive core. An electrical measurement of the coil provides information about displacement of the core. The coil has an axis extending in a first direction, wherein the housing has a minimum outside dimension that is less than 3.00 mm when measured perpendicular to that first direction. The housing has an inner surface having a housing inside dimension. The housing is for holding a displacement sensor and a guidance mechanism. The displacement sensor includes a coil and a captive core having a core outside dimension. The guidance mechanism includes a first part and a second part for guiding the core. The first part includes a bearing connected to the housing. The bearing has an axial hole having a hole dimension about equal to the core outside dimension. The core slidably extends through this axial hole.

Abstract: A position sensing assembly includes a bearing element and a helically shaped rotational member used to drive a portion of a sensor assembly, such as a Digital Rotary Magnetic Encoder. Interaction between the bearing element and a helically shaped rotational member minimizes the presence of backlash in the position sensing assembly. Accordingly, as an actuator assembly drives both a control element, such as a flight control surface, and the position sensing assembly, the sensor assembly generates an output signal that accurately reflects the position of the control element.

Abstract: A method for extracting peak information from an amplitude varying sinusoidal waveform output from a sensor is provided. The method includes gating a counter with a keying signal having a keying-signal period generated by a sinusoidal waveform associated with the amplitude varying sinusoidal waveform, receiving high frequency clock signals at the gated counter during keying-signal periods, wherein a clock-signal period is much less than the keying-signal periods, disabling the counter at the end of each keying-signal period, generating a quarter-count value based on the disabling, and outputting a sample pulse associated with each keying-signal period. If a current-keying-signal period is the same as a last-keying-signal period, the sample pulse is generated at a quarter-wave of the sinusoidal waveform. If the current-keying-signal period differs from the last-keying-signal period, the associated output sample pulses are adjusted to the quarter-wave of the sinusoidal waveform in the next-keying-signal period.

Abstract: A method for restoring navigation failure information in a fluoroscopy-based imaging system is disclosed. The method includes obtaining a plurality of receiver navigation information using a calibration target rigidly attached to a supporting member of the imaging system. The calibration target may include a plurality of receivers providing navigation information and the supporting member may be a C-arm. The method identifies a navigation failure and corresponding to the navigation failure a calibrated receiver navigation information is generated. The calibrated receiver navigation information is generated using a calibration information and a C-arm imaging position obtained during navigation failure. A receiver navigation information corresponding to the navigation failure is estimated using the calibrated receiver navigation information, and a transmitter navigation information.

Abstract: Methods of detecting anomalies in ambient alternating current (AC) fields are provided. An exemplary embodiment of such a method includes the steps of placing an AC field sensor in an ambient AC field, generating a signal representative of the ambient AC field received by the sensor, and processing the signal to determine if the ambient AC field includes any anomalies. Various applications for the methods are also provided.

Abstract: The invention relates to position sensors of the linearly variable induction difference type. When cost constraints prevent the use of transformers with guaranteed phase-shift tolerance to achieve an accuracy objective, it is advantageous to provide an independent demodulation of the signals of the two windings. The error signal thus has a lower dependence on the phase shift and the accuracy is typically enhanced by a factor greater than an order of magnitude.

Abstract: Elongation measurement apparatuses and systems comprise at least two Linear Variable Differential Transformers (LVDTs) with a push rod coupled to each of the at least two LVDTs at one longitudinal end thereof. At least one push rod extends to a base and is coupled thereto at an opposing longitudinal end, and at least one other push rod extends to a location spaced apart from the base and is configured to receive a sample between an opposing longitudinal end of the at least one other push rod and the base. Nuclear reactors comprising such apparatuses and systems and methods of measuring elongation of a material are also disclosed.

Abstract: A single housing with a non-ferromagnetic piezo-driven flexure has primary and secondary coil forms of different diameters, one coaxially inside the other, integrated in the flexure. The cylinders defining the planes of the primary and secondaries do not spatially overlap. The secondary coil forms may be wound in opposite directions and wired to provide a transformer device. Movement of the primary relative to the secondaries in the direction of the central axis of the coils can be differentially detected with high precision.

Abstract: A brushless resolver (10) comprises exciting signal transmitting means for transmitting a resolver exciting signal from the stator (3) side to the rotor (4) side in a noncontact way and a resolver part (7) for modulating the resolver exciting signal according to the angle of rotation to be detected. The resolver part (7) also serves as exciting signal transmitting means. The resolver part (7) is constituted of a pair of a rotor (4) composed of a rotor iron core (43) having slots and wrapped with a rotor winding (44) and a stator (3) composed of a stator iron core (33) having slots and wrapped with a stator winding (34). The manufacturing cost can be lowered, and an arbitrary shaft multiple angle such as a shift multiple angle 1 can be set up.

Abstract: An actuator having a fixed part, a movable part movable with respect to the fixed part in a travelling direction, and a non-contact position sensor connected to the movable part to read the position of the movable part. The position sensor has a reading device connected to the fixed part and having a ferromagnetic core; and a magnetic cursor, which is integrated in the movable part, is defined by a magnetized portion of the movable part, and is so magnetized as to locally saturate the ferromagnetic core at the magnetic cursor.

Abstract: A plurality of layers of flat coils are stacked and connected in series with each other to form a single coil pole, and the coil pole is energized by an A.C. signal. Magnetism-responsive member, provided to be opposed to the coil pole in a non-contact manner, is displaced relative to the coil pole, so that correspondency, to the coil section, of the magnetism-responsive member varies in response to variation in the relative position and thus impedance variation occurs in the coil pole. Position detection signal is provided on the basis of an output signal, responsive to the impedance variation, taken out from the coil pole.

Abstract: The invention relates to an inductive sensor unit having one or more sensor coils, which have been mounted on a printed circuit board in a planar manner. According to the invention, a change in the inductance of the sensor coils caused by leakage currents in the conductive actuator is correlated with the position of the actuator with regard to the distance from the sensor coil and with the overlapping of the sensor (at a fixed distance). This provides the basis for an inductive momentary contact switch and an inductive position switching device. The invention also relates to the evaluation of the inductance, e.g. of the momentary contact switch such as in inductive proximity switches by incorporating the inductive sensors in an oscillating circuit. Alternatively, the change in inductance can also be detected by a reactance measurement. A relative evaluation of the influence of adjacent sensor coils is carried out in position switching devices.

Abstract: An air-core transformer position sensor includes an excitation coil, an output coil, and a sensor coil. The excitation coil is adapted to be electrically excited with an excitation signal. The output coil is inductively coupled to the excitation coil upon electrical excitation of the excitation coil. The sensor coil is electrically shorted, is movable relative to the excitation coil and the output coil and, upon electrical excitation of the excitation coil, is inductively coupled to at least one of the excitation coil or the output coil.

Abstract: A valve actuator is provided that comprises a unitary housing and a piston translatably mounted within the housing. The piston comprises a first portion having a first diameter and a second portion having a second diameter that is greater than the first diameter. A position sensor having a third diameter at least as large as the second diameter is fixedly coupled to the housing and to the piston for determining the position of the piston.

Abstract: An apparatus including a controller, a transport in communication with the controller having a movable portion and a transport path and a multi-dimensional position measurement device in communication with the controller, the multi-dimensional position measurement device including a plurality of transformers and at least one element attached to the movable portion, wherein the multi-dimensional position measurement device is configured so that a circuit is completed in at least one plurality of transformers as the at least one element passes proximate to the at least one of the plurality of transformers and the controller is configured to calculate a multi-dimensional position of the movable object based on an output of the at least one of the plurality of transformers, wherein the multi-dimensional position includes at least a gap between the movable portion and the plurality of transformers.

Abstract: The invention relates to a preferably ferriteless inductive proximity switch having at least one transmitting coil, one oscillator circuit and at least two receiving coils arranged in the alternating magnetic field of the transmitting coil, whereby the transmitting coil and the receiving coil are arranged adjacent to each other on a printed circuit board, and also having an evaluation circuit connected to the receiving coil for evaluating the received signal of the receiving coils when a target approaches the proximity switch.

Abstract: A position sensor has a moving coil part that is formed from a first coil form formed of a non ferromagnetic material, and a second coil that also has its form made of non-ferromagnetic material. The coil forms can be formed of non ferromagnetic adhesive. One of the coils moves relative to the other. The stationary coil part sufficiently close to said moving coil part such that magnetic flux from said moving coil part is induced into said stationary coil part. A primary coil is driven with a voltage. The operation senses voltages induced into a plurality of secondary coils, from movement of the primary coil relative to the secondary coils. The sensing can be done using a differential amplifier.

Abstract: An air-core transformer position sensor includes an excitation coil, an output coil, and a sensor coil. The excitation coil is adapted to be electrically excited with an excitation signal. The output coil is inductively coupled to the excitation coil upon electrical excitation of the excitation coil. The sensor coil is electrically shorted, is movable relative to the excitation coil and the output coil and, upon electrical excitation of the excitation coil, is inductively coupled to at least one of the excitation coil or the output coil.

Abstract: A movement distance sensor operates as a differential transformer with a primary coil, at least two secondary coils. A circuit configuration is connected to the secondary coils in order to determine a movement distance. The circuit configuration includes a multiplexer, an A/D converter, and a digital logic module. The multiplexer is connected to the first and the second secondary coil via an input stage. The output of the multiplexer is connected to the input of the A/D converter and the output of the A/D converter is passed to the input of the digital logic module. The latter determines the movement distance from the input signals received alternately from the multiplexer. The measurement configuration exhibits high reliability with low error tolerances.

Abstract: A linear variable differential transformer (LVDT) system is disclosed. The system has an LVDT. A signal conditioner circuit is coupled to the LVDT. The signal conditioner circuit uses an inductance of the LVDT primary as a micro-power excitation carrier frequency to lower a drive power of the system. The signal conditioner circuit generates output currents that are summed and filtered to generate a position proportional voltage.

Abstract: A force detecting element is used to move a moving coil that is formed without ferromagnetic materials and is driven using a stationary coil that is formed without ferromagnetic materials, thereby producing an output signal which is more linear than the previous techniques. The output signal produces an output indicative of a resolution in the range of microns or less.

Abstract: An outer ring is provided with the stator of a resolver, and a ring member with the rotor of the resolver. The stator comprises an annular core and a winding provided around the core. The ring member is provided at a position opposed to the stator with an eccentric cylindrical face serving as the rotor and eccentric with respect to other outer peripheral surface of the ring member.

Abstract: A linear variable transformer (LVDT) for use in a transducer. The LVDT has a non-ferromagnetic core which may eliminate Barkhausen noise and thereby improve the sensitivity of the resulting measurements. In one aspect, this system may be used in an atomic force microscope.

Abstract: A linear variable differential transformer (LVDT) is disclosed that has first and second coil is formed of materials that minimize the Barkhausen noise, and hence which produces outputs that are substantially independent of any Barkhausen noise. In an embodiment, the Barkhausen independence is formed by making the coils of non-ferromagnetic materials. For example, other materials could be used that have a material as the core that does not include grain boundaries or does not include metastable magnetic.

Abstract: An apparatus and method for determining a linear position from a linear variable differential transformer (LVDT) including a primary coil driven by an excitation signal, and two secondary coils coupled to two correlated signals. The method includes converting the correlated signals to a digital estimate, for each of the correlated signals, and evaluating an amplitude of the correlated signals to determine the linear position. The process of converting the correlated signals comprises comparing the correlated signal to an analog feedback signal to generate a comparison result and incrementally adjusting the digital estimate in response to sampling the comparison result at an estimation frequency.

Abstract: A resolver unit having a structure in which the axial length is shortened to prevent the magnetic coupling characteristic between the rotary and stationary sides from being impaired, a winding generates more magnetic fluxes, and multiplexing is easily conducted, and also a resolver using such a resolver unit are provided.