Inductive sensor

About: Inductive sensor is a research topic. Over the lifetime, 2282 publications have been published within this topic receiving 21984 citations.

Analysis of the natural modes of the 3-D eddy current problem based on the finite integration technique

Abstract: Low-frequency, broadband electromagnetic induction (EMI) sensors have been shown to be highly effective at detecting and classifying buried conducting targets. Even the simplest inductive sensors are capable of easily detecting the presence of buried metal. It is difficult, however, for most inductive sensors to discriminate between targets of interest, and the ubiquitous metallic clutter that might be buried alongside it. One attractive solution to this discrimination problem is to invert the broadband frequency data collected by the EMI sensor, finding a pole-expansion representation of the scattering transfer function known as its discrete spectrum of relaxation frequencies (DSRF). A target's low-frequency scattering behavior can then be compactly described by a set of relaxation frequencies that are the poles of the transfer function and their coefficients that are the corresponding amplitudes. Discrimination can be achieved by comparing the inverted data to a dictionary that contains the theoretical DSRFs of targets of interest. In this paper, a computational method will be presented for modeling the DSRF of arbitrarily-shaped three-dimensional conducting targets.

Proximity sensor system having a proximity sensor with a bipolar signal output

Abstract: The present invention relates to a proximity sensor system comprising a sensor generating two types of pulse signals having opposite polarities in order to detect two different, small, metallic objects and to distinguish the objects. The proximity sensor system can involve at least two metallic objects to be detected having different magnetic properties; a sensor comprising a magnetic core having a plurality of legs and a toroidal coil winding fitted and supported onto at least one of the legs of the magnetic core; and an electronic circuit processing output signals from the sensor. The sensor generates predetermined signals having opposite polarities when metallic objects pass in proximity to the sensor. Suitable metallic objects include those made of ferromagnetic metal and diamagnetic or paramagnetic metal. The sensor generates a positive pulse signal when the ferromagnetic metallic object passes by the sensor, and the sensor generates a negative pulse signal when the diamagnetic or paramagnetic metallic object passes by the sensor.

An ATM machine protective cabin door electronic system with adjustable person detecting sensitivity and an achieving method thereof

Abstract: An ATM machine protective cabin door electronic system with adjustable person detecting sensitivity and an achieving method thereof are disclosed. According to the system, a cabin door controller unit is connected to a human body inductive sensor the sensitivity of which is controlled by a first mode to a third mode, a voice input circuit having a microphone disposed in the cabin and a voice output circuit having a loudspeaker disposed outside the cabin, the height from a detecting space to the ground in the cabin when the human body inductive sensor is in the first mode is smaller than that when the human body inductive sensor is in the second mode and is larger than that when the human body inductive sensor is in the third mode, and steps are disposed before the ATM machine. According to the method, when an entrance button unlocking function is shielded, the human body inductive sensor works under the second mode and the third mode alternatively to recognize faint and trapped phenomena, and if no person is detected under the third mode, it is determined that a person faints and unlocking is performed; when a voice signal amplitude smaller than a preset value and higher than a preset value of threshold time is recognized and a person is detected only under the third mode, a child is determined to be trapped and unlocking is performed; and corresponding voice help seeking information is output from the loudspeaker during unlocking.

Spectrographic material analysis using multi-frequency inductive sensing

Abstract: A multi-frequency inductive sensing system can be used for spectrographic material analysis of a conductive target material (such as tissue) based on electrical impedance spectroscopy. An inductive sensor can be driven with an excitation current at multiple sensor excitation frequencies (ω) to project a time-varying magnetic field into a sensing area on the surface of the target material, inducing eddy currents within the target material. The inductive sensor can be characterized by a sensor impedance Z(ω) as a function of the sensor excitation frequency (ω), and the resulting induced eddy currents. Multiple sensor impedance Zs(ω) measurements, at the multiple sensor excitation frequencies (ω), can be determined, which represent electromagnetic properties of the target material (such as permittivity e, permeability μ, and resistivity ρ), based on the induced eddy currents. The multiple sensor excitation frequencies (ω), and corresponding multiple sensor impedance Zs(ω) measurements, can be selected for particular target penetration depths.

Method for determining the position of a moving part along an axis, using an inductive sensor

Abstract: A method for determining the position θ of a moving part (T) along an axis (X), using an inductive sensor (10) including: a primary winding (B1) generating an electromagnetic field; a first secondary winding (R1), generating a first voltage signal (V1), of the sine function type; a second secondary winding (R2), generating a second voltage signal (V2) of the cosine function type; and a calculation unit (20′), wherein the method includes the steps of calculating and distributing linearization points i on the arctangent function tan(θ) resulting from the ratio of the first voltage signal to the second voltage signal, the linearization points i being distributed according to a sinusoidal function in order to reduce the error on the position (θ) of the target (T) at the ends (E1, E2) of the primary and secondary windings (R1, R2).