Aspects of the disclosure provide a sensing apparatus including a sensing device, a memory, and processing circuitry. The sensing device includes resonators having respective resonant frequencies. The resonators include an array of inductive coils positioned on a surface of the apparatus. The sensing device can output a signal indicating changes of the resonant frequencies caused by presence of an object proximate to the surface. The memory stores reference signals corresponding to reference objects. Each reference signal indicates changes of the resonant frequencies caused by the respective reference object proximate to the surface. The processing circuitry can receive, from the sensing device, a particular signal indicating changes of the resonant frequencies caused by presence of a particular object proximate to the surface. The processing circuitry compares the particular signal with the stored reference signals of the reference objects to determine an identity of the particular object.

The present invention relates to the determining of a sensor signal. For example, an enveloping waveform of the signal from a rotational angle sensor can be reconstructed for this purpose. To this end, a predefined number of successively sampled values of a signal from a rotational angle sensor are multiplied with the elements of a weighting vector. On the basis of a measurement vector weighted in this way, an enveloping waveform of a signal curve from a rotational angle sensor can then be determined and, therefrom, a phase angle can be calculated.

A caliper tool for measuring a shape of a wellbore may include a sensor assembly and a movable measurement component including a hub and a measurement arm extending from the hub, and a magnetically-permeable target coupled to the hub and configured to rotate with the hub upon movement of the measurement arm. A sensor assembly includes primary coil and one or more secondary coils spaced apart from the primary coil, wherein output signals from the secondary coils facilitates measurement of the shape of the wellbore.

A caliper tool for measuring a shape of a wellbore may include a sensor assembly and a movable measurement component including a hub and a measurement arm extending from the hub, and a magnetically-permeable target coupled to the hub and configured to rotate with the hub upon movement of the measurement arm. A sensor assembly includes primary coil and one or more secondary coils spaced apart from the primary coil, wherein output signals from the secondary coils facilitates measurement of the shape of the wellbore.

A resolver system includes a rotatable primary winding, a secondary winding fixed relative to the rotatable primary winding, a tertiary winding fixed relative to the rotatable primary winding and positioned /2 radians out of phase with respect to the fixed secondary winding, an excitation module electrically connected to the rotatable primary winding and configured to provide an excitation signal to the rotatable primary winding where the excitation signal is an alternating current waveform having a fundamental frequency, and a controller electrically connected to the secondary winding and configured to sample a voltage across the secondary winding at 18 times the fundamental frequency, sample a voltage across the tertiary winding at 18 times the fundamental frequency, and determine an amplitude of the fundamental frequency based on the sampled voltages across the secondary and tertiary windings, where the alternating current waveform includes a third harmonic frequency.

This inductive position sensor is designed to measure the angular position of a shaft or the like and includes a support on which are realized, on the one hand, a primary winding, and on the other hand, at least two secondary windings in phase opposition with respect to each other. Each secondary winding is defined by a set of at least two loops in phase with each other. The secondary windings are connected in series and each arranged symmetrically with respect to a middle line so as to form each time a pattern on either side of this middle line, the two patterns having a separation between them in the area of said middle line. An assembly including such a sensor and a target with two oppositely directed helices.

The invention relates to an inductive position sensor, comprising: a first part with a cylindrical coil winding (14) having a longitudinal direction, a second part with a soft magnetic plunger core (20). The invention also relates to the soft magnetic plunger core and a magnetic shield around said cylindrical coil winding for said inductive position sensor. According to the invention is the soft magnetic plunger core as well as the magnetic shield hollow, preferably with circular cross-section, and made from electrical steel or soft iron sheet material.

An inductive position sensor designed to measure the angular position of a shaft or the like and includes a support on which are realized, on the one hand, a primary winding, and on the other hand, at least two secondary windings in phase opposition with respect to each other. Each secondary winding is defined by a set of at least two loops in phase with each other. The secondary windings are connected in series and each arranged symmetrically with respect to a middle line so as to form each time a pattern on either side of this middle line, the two patterns having a separation between them in the area of said middle line. An assembly including such a sensor and a target with two oppositely directed helices.

A system for controlling a turbine valve is provided. The system includes a hydraulic pilot valve section being moveable in a first direction and a second direction; a main hydraulic valve section being moveable in a first direction to close the turbine valve and a second direction to open the turbine valve; a position demand indicating a desired position of the turbine valve; a first feedback indicating an actual position of the hydraulic pilot valve section; and aa second feedback indicating an actual position of the main hydraulic valve section. The system also includes a pilot valve error; a main valve error; a turbine valve error; and a pilot valve adjustment moving the hydraulic pilot valve section in response to the turbine valve error. The turbine valve error is repeatedly determined and the pilot valve adjustment repeatedly moves the hydraulic pilot valve section to minimize the turbine valve error.

A position sensing system includes a linear variable differential transformer (LVDT) to provide a first output voltage and a second output voltage. The position sensing system also includes two precision rectifiers. Each of the precision rectifiers comprises only operational amplifiers and resistors and obtains the first output voltage or the second output voltage as an input and to provide a full-wave rectified output.