Moving Magnet Technologies (mmt)

Moving Magnet Technologies

Gérald Masson

Didier Frachon

Stéphane Biwersi

Thierry Dorge

Yannick Ronnat

Daniel Prudham

Michaël Delbaere

Richard Arlot

Nikola Jerance

Stephane Biwersi

Mickaël Delbaere

The disclosure relates in particular to a method for parameterizing a system for measuring an absolute position, the system including a permanent magnet, at least one probe that is mobile relative to the magnet over a given path, and a controller providing position information calculated on the basis of the arctangent of the ratio, wherein a correction coefficient G is assigned, between the output signals of the probe, wherein the signals are pseudo-sinusoidal and squared. The method includes an optimization operation that involves selecting the value of the coefficient G that minimizes the errors of the measurement system resulting from the pseudo-sinusoidal character of the signals output from the probe.

Position sensor

The disclosure relates to a magnetic device for detecting the absolute position of an input shaft capable of rotating more than 360&#xb0;, the device including a main magnetic sensor, a motion reducer, and a secondary magnetic sensor, wherein the main magnetic sensor is connected to a rotor, measures the rotation of the shaft for ranges of angles of less than 360&#xb0;, and includes a main magnet, the motion reducer converts the rotation of the shaft into a reduced rotation, the maximum amplitude of which is equal to no more than 360&#xb0;, and the secondary magnetic sensor measures the reduced rotation and includes a secondary magnet. According to the disclosure, the secondary magnet is arranged between the upper and lower planes of the main rotor, and the main magnet has P pairs of poles, where P is greater than 1.

Magnetic multi-turn absolute position detection device

The present disclosure relates to a magnetic position sensor with field direction measurement and a flux collector. The disclosure proposes to measure two magnetic induction components at one and the same point, harmonizing the amplitude of the two magnetic induction components using flux collectors so as to have a ratio of the amplitudes of these two components close to one. For this purpose, the disclosure provides a contactless position sensor including at least one permanent magnet, emitting a magnetic field, at least one detection element sensitive to the direction of the magnetic field, and at least one pair of flux collectors, the permanent magnet being capable of moving in a direction of displacement and having a direction of magnetization that can be continuously varied according to the direction of displacement. Each flux collector has at least one portion, provided with an end, extending substantially along the direction of displacement of the magnet. The ends of a pair of flux collectors define a gap oriented along the direction of displacement of the magnet. The detection element is positioned outside the gap and substantially equidistant from the ends.

Magnetic position sensor with field direction measurement and flux collector

The invention relates to an absolute position magnetic sensor for measuring the angular position, on a theta course, of a shaft passing through said sensor and comprising at least two systems for detecting the position of the shaft. Said invention is characterised in that: at least one of the detection systems generates a signal according to a 'periodical' function of the theta/n period giving the periodical angular position of said shaft; at least one of the detection systems generates an absolute signal on a theta course of the shaft; and theta and n fit the equation:*theta/=360*&#x3e;1.

Non-contact multi-turn absolute position magnetic sensor comprising a through-shaft

The disclosure relates to a magnetic position sensor in at least two directions, the sensor including at least one magnetized element and a probe including at least two magneto-sensitive elements located substantially on the same point and each measuring one of the components of the magnetic field generated by the magnetized element, the magnetized element being movable relative to the magneto-sensitive elements. The probe includes at least one processing circuit capable of carrying out angle and module calculations on the basis of algebraic combinations of the components of the magnetic field and providing at least two independent signals representing the position of the movable element along, respectively, one and the other of the two directions. According to the disclosure, the magnetization vector of the magnetized element is variable in relation to the normal vector on the surface of the magnetized element that is placed opposite the probe in at least one of the dimensions of the magnetized element so as to define a single position of the probe in relation to the magnetized element.

Bidirectional magnetic position sensor having field rotation

The disclosure relates to a magnetic position sensor including at least one permanent magnet. The disclosure also relates to a magnetic device for detecting a torque between a first shaft and a second shaft that are connected via a torsion bar. The aim of the disclosure is to provide a device for determining the multi-periodic absolute position of a magnetized unit. The subject of the disclosure is therefore a magnetic position sensor including at least the following: a magnetized unit, a first magnetosensitive probe and a second magnetosensitive probe. The second magnetosensitive probe is capable of measuring a number of complete rotations of the magnetic field in an absolute, incremental and reversible manner so as to determine a second datum relating to the position of the magnet, whether or not this second magnetosensitive probe is powered. The sensor further includes a module for calculating the absolute position of the magnet on the basis of the first and second data coming from the first and second probes respectively.

Magnetic multi-periodic absolute position sensor

The invention relates to an angular or linear magnetic position sensor that comprises a mobile member including at least one magnet () having a magnetization direction that varies linearly along the movement direction of the magnet in a surface defined by said movement direction and in a normal direction, at least four magneto-sensitive elements (and) and at least one processing circuit () providing a signal based on the absolute position of the mobile member, characterized in that a first set of magneto-sensitive elements () and () are located at a same point, the first couple of magneto-sensitive elements () being spatially offset from a second couple of magneto-sensitive elements () along the movement direction, and in that the magneto-sensitive elements (and) measure the tangential component of the magnetic field while the magneto-sensitive elements (and) measure the normal component of the magnetic field in order to provide, after algebraic combination of the components taken in pairs, two sinusoidal signals substantially having an electrical phase shift of 90&#xb0;.

Angular or linear magnetic position sensor not sensitive to external fields

A position sensor, which can detect a steering column twist of a first magnetic rotoric structure including a plurality of radially oriented magnets and a second statoric structure including two concentric gear rings extended by radially oriented teeth. The rotoric structure is substantially disc-shaped and includes a ferromagnetic head supporting the plurality of magnets, the statoric structures are provided with interleaving teeth and the position sensor includes a third collector structure including two flow closing parts, one of which is fixed, and which define at least one air gap in which at least one magnetosensitive element is arranged.

Short stroke magnetic position sensor, in particular for measuring a steering column twist

The invention relates to a position sensor which is intended, in particular, for detecting a steering column torsion. The invention consists of: a first magnetic rotor structure () comprising a plurality of radially-oriented magnets; a second stator structure comprising two rings () which extend into axially-oriented overlapping teeth (); and a third fixed collector structure () comprising two flux-closing parts which define at least one air gap in which at least one magneto-sensitive element is placed. The invention is characterized in that the flux-closing parts and the stator rings () define therebetween a constant collection surface that is independent of the relative radial position of the two structures.

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Besançon, France

Gérald Masson