An inductive sensor device for detecting a reciprocating movement of an object includes an oscillator circuit and a processing unit. The oscillator circuit has a sensing coil configured for inducing eddy currents in the object. The processing unit is configured to count a plurality of oscillations of the oscillator circuit detected in a plurality of sampling periods, compare the oscillations with a predetermined mean value of oscillations, and determine both a speed and a position of the object based on a comparison of the oscillations with the predetermined mean value of oscillations.

An inductive sensor device for detecting a reciprocating movement of an object includes an oscillator circuit and a processing unit. The oscillator circuit has a sensing coil configured for inducing eddy currents in the object. The processing unit is configured to count a plurality of oscillations of the oscillator circuit detected in a plurality of sampling periods, compare the oscillations with a predetermined mean value of oscillations, and determine both a speed and a position of the object based on a comparison of the oscillations with the predetermined mean value of oscillations.

A transducer for an inductive displacement sensor includes a secondary winding of 2N turns of alternating directions extending in a zone of length D.sub.tot, the winding including: a first coiled conductive section forming N half-turns, extending between a first end of the winding, situated at the midpoint of the length D.sub.tot, and a first point of the winding, situated at one end of the length D.sub.tot; a second section forming N half-turns, extending between the first point and a second intermediate point situated at the midpoint of the length D.sub.tot; a third section forming N half-turns, extending between the second point and a third intermediate point situated at a second end of the length D.sub.tot; and a fourth section forming N half-turns, extending between the third point and a second end of the winding situated at the midpoint of the length D.sub.tot.

A target for an inductive displacement sensor is provided, including a plurality of conductive patterns distributed along a zone having a dimension D.sub.tot in a direction, the patterns being defined by the overlay of at least a first set of elementary periodic patterns having a period approximately equal to D.sub.tot/N, including N first elementary conductive patterns of a dimension approximately equal to D.sub.tot/2N in the direction, regularly distributed along the zone, and of a second set of elementary periodic patterns having a period approximately equal to D.sub.tot/(N+r), including N+r second elementary patterns of a dimension approximately equal to D.sub.tot/2(N+r) in the direction, regularly distributed along the zone, where N is an integer greater than or equal to 2 and r is a positive integer, different to zero and less than or equal to N1, wherein first and second elementary conductive patterns overlap at least partially.

A speed measurement method, system and apparatus of a medium and low speed maglev train are provided. The method comprises: determining a position of a marked eddy current sensor for each eddy current pulse of each of two eddy current pulse data groups based on the eddy current pulse, distribution data of maglev steel rail sleepers and eddy current sensors; determining a first speed value based on positions of marked eddy current sensors and pulse moments respectively corresponding to two adjacent eddy current pulses; calculating a second speed value based on a first speed value corresponding to an eddy current pulse data group of which pulse moment is ranked ahead in the two eddy current pulse data groups and an acceleration sensing data; calculating a third speed value based on radar sensing data; and fusing the first, second and third speed values to obtain a final speed value.

A position detection device for detecting a position of a moving member moving forward and backward in a predetermined moving direction is provided with a detection object attached to the moving member, a substrate provided with an excitation coil for generating a magnetic field in an area including the detection object and a detection coil being interlinked with a magnetic flux of the magnetic field, a power supply unit for supplying an alternating current to the excitation coil, and a calculation unit that calculates the position of the moving member based on an output voltage of the detection coil. The detection coil is shaped as a combination of a pair of curved portions that are symmetrical across a symmetry axis parallel to the moving direction of the moving member. Each of the curved portions is shaped as a sinusoidal fundamental wave component superimposed with a harmonic component of a third or higher order multiplied by each of coefficients corresponding to the order. The coefficients are adjusted in such a manner that a peak value of a voltage induced in the detection coil changes sinusoidally when the detection object moves at a constant speed relative to the substrate while facing a part of the substrate.

A position detection device for detecting a position of a moving member moving forward and backward in a predetermined moving direction is provided with a detection object attached to the moving member, a substrate provided with an excitation coil being positioned to face the moving member and parallel to the moving direction of the moving member for generating a magnetic field in an area including the detection object, and a detection coil being interlinked with a magnetic flux of the magnetic field, a power supply unit for supplying an alternating current to the excitation coil, a calculation unit that calculates the position of the moving member based on an output voltage of the detection coil, and a spacing fluctuation suppression structure that suppresses fluctuations in a spacing between a facing surface facing the detection object and the detection object in the substrate.

Disclosed is a transducer for an inductive displacement sensor, including a secondary winding of 2N turns of alternating directions extending in a zone of length D.sub.tot, the winding including: a first coiled conductive section forming N half-turns, extending between a first end of the winding, situated at the midpoint of the length D.sub.tot, and a first point of the winding, situated at one end of the length D.sub.tot; a second section forming N half-turns, extending between the first point and a second intermediate point situated at the midpoint of the length D.sub.tot; a third section forming N half-turns, extending between the second point and a third intermediate point situated at a second end of the length D.sub.tot; and a fourth section forming N half-turns, extending between the third point and a second end of the winding situated at the midpoint of the length D.sub.tot.

Disclosed is a target for an inductive displacement sensor, including a plurality of conductive patterns distributed along a zone having a dimension D.sub.tot in a direction, the patterns being defined by the overlay of at least a first set of elementary periodic patterns having a period approximately equal to D.sub.tot/N, including N first elementary conductive patterns of a dimension approximately equal to D.sub.tot/2N in the direction, regularly distributed along the zone, and of a second set of elementary periodic patterns having a period approximately equal to D.sub.tot/(N+r), including N+r second elementary patterns of a dimension approximately equal to D.sub.tot/2(N+r) in the direction, regularly distributed along the zone, where N is an integer greater than or equal to 2 and r is a positive integer, different to zero and less than or equal to N1, wherein first and second elementary conductive patterns overlap at least partially.

A position detection device for detecting a position of a moving member moving forward and backward in a predetermined moving direction is provided with a detection object attached to the moving member, a substrate provided with an excitation coil for generating a magnetic field in an area including the detection object and a detection coil being interlinked with a magnetic flux of the magnetic field, a power supply unit for supplying an alternating current to the excitation coil, and a calculation unit that calculates the position of the moving member based on an output voltage of the detection coil. The detection coil is shaped as a combination of a pair of curved portions that are symmetrical across a symmetry axis parallel to the moving direction of the moving member. Each of the curved portions is shaped as a sinusoidal fundamental wave component superimposed with a harmonic component of a third or higher order multiplied by each of coefficients corresponding to the order. The coefficients are adjusted in such a manner that a peak value of a voltage induced in the detection coil changes sinusoidally when the detection object moves at a constant speed relative to the substrate while facing a part of the substrate.