EP1135781B1 - Bidirectional actuators - Google Patents

Abstract

The invention concerns a bidirectional actuator comprising at least a stator structure excited by an electric coil, and a mobile magnet in a main gap, the stator structure consists of two pairs of stator poles (1 to 4), each of the pairs of poles being enclosed by a least an electric coil, the stator structure defining at least a first auxiliary gap (6, 8) for the displacement of the mobile magnet (14) relatively to a first degree of freedom, and a second auxiliary gap (7, 9) for the displacement of the magnet (14) relatively to a second degree of freedom.

Description

The present invention relates to the field of electromagnetic actuators.

Unidirectional actuators using a stator structure excited by an electric coil, producing a variable magnetic flux ensuring the positioning of a movable magnet, are known. By way of example, US Pat. No. 4,918,987 describes such an actuator comprising a stator having two poles each surrounded by a coil. The moving magnet is subjected to a linear force as a function of the flux generated by the coils.

German patent DE3037648 describes a two-dimensional actuator which may comprise either moving coils or moving magnets. The solution comprising moving coils is not satisfactory because it induces high industrialization costs. The described solution comprising moving magnets requires the use of 8 moving magnets. Such an architecture requires multiple control signals and computer processing for controlling the XY position.

Also known is patent US5062055 which relates to the electromagnetic actuators producing both a rotational movement and a translational movement. Such a prior art actuator comprises a cylindrical magnet having magnetization boundaries in the peripheral direction and in the axial direction, in which a multipole magnetization is established in the axial direction, and yokes carrying coils having Magnetic poles located opposite the magnetization boundaries. Such an actuator uses a magnet having several pairs of poles with directions of magnetization perpendicular to each other.

The purpose of the present invention is to propose an actuator for controlling the positioning of a member according to two degrees of freedom, for example in a plane along two perpendicular axes XY, or according to a degree of freedom in translation and a degree of freedom in rotation, or in spherical rotation, with simple control signals.

For this purpose, the invention relates in its most general sense to a bidirectional actuator comprising at least one stator structure excited by an electric coil, and a single movable magnet having a single polarity. This magnet is placed in a main air gap. The stator structure is composed of two stator parts. Each of the stator parts has at least one secondary air gap and is excited by at least one electric coil. The stator structure has at least one gap for moving the movable magnet relative to a first degree of freedom, and at least a second secondary gap for moving the movable magnet relative to a second degree of freedom.

According to a particular mode of implementation, the movable magnet is integral with the cylinder head.

According to a first variant, the stator structure is composed of 4 poles made of a soft magnetic material defining between them two pairs of secondary air gaps intersecting at a midpoint and in that the main air gap is plane.

Advantageously, the stator poles are constituted by two pairs of rectangular pieces, each pair of parts being excited by at least one electrical coil and each defining a secondary air gap.

Preferably, the ratio L / E between the thickness L of the magnet and the thickness E of the gap is between 1 and 2.

Advantageously, the dimensions of the secondary air gaps are C ₁ + E and C ₂ + E, where C ₁ and C ₂ denote the stroke of the moving magnet according to the two directions of the secondary air gaps and in that the dimensions of the magnet are C ₁ + d ₁ + E and C ₂ + d ₂ + E, d ₁ and d ₂ denoting the width of said secondary airships.

According to a particular variant, the stator structure is composed of two stator pieces disposed on either side of the magnet, each of the stator pieces having a pair of stator poles, the pair of stator poles of one of the pieces being oriented perpendicular to the pair of stator poles of the other stator part.

According to a second variant embodiment, the magnet is of tubular shape and is movable in a first degree of freedom in axial translation and in a second degree of freedom in axial rotation with respect to a stator structure formed of 4 stator poles in the form of portions of cylinders having a first secondary air gap in the longitudinal median plane, in which a first electric coil is placed, and a second secondary air gap in the transverse plane, in which a second coil is placed. Each of these coils is preferably wrapped around a ferromagnetic core.

According to one variant, the magnet is of tubular shape and is movable in a first degree of freedom in axial translation and in a second degree of freedom in axial rotation with respect to an outer cylindrical stator structure formed of 4 stator poles having a concave surface defining the main air gap with the cylindrical yoke placed inside the magnet, each of the four stator poles being surrounded by an electric coil.

According to another variant, the magnet is of tubular shape and is movable in a first degree of freedom in axial translation and in a second degree of freedom in axial rotation with respect to a cylindrical stator structure constituted by a first external stator piece for displacement according to a first degree of freedom, and a second internal stator piece for displacement according to a degree of freedom, each of the stator parts comprising at least one electric excitation coil.

According to a third embodiment, the magnet is of spherical shape and is rotatable in spherical rotation with respect to a spherical cap-like stator structure formed of 4 stator poles in the form of a cap sector, comprising two coils housed in grooves. peripherals whose median planes are perpendicular.

Advantageously, the magnet is of spherical shape and is movable in spherical rotation with respect to a stator structure of tubular form formed of 4 quarter-tube-shaped stator poles, surrounded by an electric coil.

According to a particular variant of such an actuator, the main air gap is of spherical shape.

According to another particular variant, the magnet is spherical in shape and surrounds a spherical yoke, and is rotatable around a stator structure of semispherical shape formed of 4 quarter-sphere-shaped stator poles.

According to a particular embodiment, the magnet is spherical in shape and surrounds a spherical yoke, and is movable in spherical rotation around a stator structure formed of two half-spherical stator parts.

• Les figures 1 et 2 représentent des vues schématiques respectivement en vue transversale, et de la partie statorique d'une première variante de réalisation sous la forme d'un actionneur linéaire XY ;
• les figures 3a et 3b illustrent le fonctionnement de l'actionneur ;
• les figures 4 et 5 représentent des vues d'une variante de réalisation d'un actionneur XY ;
• les figures 6 et 7 représentent des vues schématiques respectivement en vue transversale, et de la partie statorique d'une première variante de réalisation sous la forme d'un actionneur linéaire XY ;
• les figures 8 et 9 représentent une variante d'un actionneur cylindrique x-θ, respectivement sans et avec l'aimant ;
• les figures 10 à 12 représentent des vues en perspective, respectivement sans et avec aimant, et en coupe transversale, d'un actionneur linéaire-rotatif.;
• les figures 13 à 16 représentent des vues en perspective, respectivement sans et avec aimant, et en vue transversale, et en vue éclatée d'une deuxième version d'un actionneur linéaire-rotatif ;
• les figures 17 à 19 représentent des vues en perspective, respectivement sans et avec aimant, et de la partie statorique d'une troisième version d'un actionneur linéaire-rotatif ;
• les figures 20 et 21 représentent une variante de réalisation d'un actionneur de type « linéaire et rotatif extérieurs » ;
• les figures 22 et 23 représentent une deuxième version d'un actionneur de type « linéaire et rotatif extérieurs » ;
• les figures 24 et 25 représentent une troisième version d'un actionneur de type « linéaire et rotatif extérieurs » ;
• la figure 26 représente une première version d'une variante de type « Linéaire intérieur, rotatif extérieur » ;
• les figures 27 et 27b représentent une version modifiée d'une variante de type « Linéaire intérieur, rotatif extérieur » ;
• les figures 28 et 29 représentent, en vue de trois quart face et en vue transversale, une deuxième version d'une variante de type « Linéaire intérieur, rotatif extérieur » ;
• les figures 30 et 31 décrivent un actionneur de type « Linéaire extérieur, rotatif intérieur respectivement de trois quarts face et en vue partiellement coupée ;
• la figure 32 représente une vue de trois quarts face de l'ensemble stator d'une variante de type « Linéaire extérieur, rotatif intérieur » ;
• les figures 33 et 34 représentent des vues d'un actionneur sphérique et du stator d'un tel actionneur ;
• la figure 35 représente une vue d'une deuxième version d'actionneur sphérique ;
• la figure 36 représente une vue d'une troisième version d'actionneur sphérique ;
• les figures 37 et 38 représentent des vues de trois quart face et en coupe d'une quatrième version d'actionneur sphérique ;
• les figures 39 et 40 représentent des vues de trois quart face et en coupe d'une cinquième version d'actionneur sphérique ;
• les figures 41 et 42 représentent des vues de trois quart face et en coupe d'une sixième version d'actionneur sphérique :
• les figures 43 et 44 représentent des vues de trois quart face et en vue transversale d'un actionneur avec détecteur de position ;

The invention will be better understood on reading the description which follows, with reference to nonlimiting examples of embodiment, illustrated by the appended drawings in which:

• Figures 1 and 2 show schematic views respectively in a transverse view, and the stator portion of a first embodiment in the form of a linear actuator XY;
• Figures 3a and 3b illustrate the operation of the actuator;
• Figures 4 and 5 show views of an alternative embodiment of an XY actuator;
• Figures 6 and 7 show schematic views respectively in a transverse view, and the stator portion of a first embodiment in the form of a linear actuator XY;
• Figures 8 and 9 show a variant of a cylindrical actuator x-θ respectively without and with the magnet;
• Figures 10 to 12 show perspective views, respectively without and with magnet, and in cross section, of a linear-rotary actuator;
• Figures 13 to 16 show perspective views, respectively without and with magnet, and in cross-sectional view, and exploded view of a second version of a linear-rotary actuator;
• Figures 17 to 19 show perspective views, respectively without and with magnet, and the stator portion of a third version of a linear-rotary actuator;
• Figures 20 and 21 show an alternative embodiment of an actuator type "linear and rotary exterior";
• Figures 22 and 23 show a second version of an actuator type "linear and rotary exterior";
• Figures 24 and 25 show a third version of an "external linear and rotary" type actuator;
• FIG. 26 represents a first version of a variant of the type "Linear inside, rotating outside";
• Figures 27 and 27b show a modified version of a variant of the type "internal linear, external rotary";
• Figures 28 and 29 show, for three-quarter face and in cross-section, a second version of a variant of the type "internal linear, rotating external";
• FIGS. 30 and 31 describe an actuator of the "external linear, rotational internal type respectively of three quarters face and partially cut;
• Figure 32 shows a three-quarter front view of the stator assembly of a variant of the type "linear outer, rotating interior";
• Figures 33 and 34 show views of a spherical actuator and the stator of such an actuator;
• FIG. 35 represents a view of a second version of spherical actuator;
• Fig. 36 is a view of a third version of a spherical actuator;
• Figures 37 and 38 show three-quarter-sided and sectional views of a fourth version of spherical actuator;
• Figures 39 and 40 show views of three quarter face and section of a fifth version of spherical actuator;
• FIGS. 41 and 42 show three quarter-sided and sectional views of a sixth version of a spherical actuator:
• FIGS. 43 and 44 show three-quarter front and transverse views of an actuator with position detector;

The invention relates to a new type of actuator for moving a moving part in two degrees of freedom.

• Applications informatiques : souris, joystick
• Applications industrielles : pick and place
• Applications automobiles : assistance au passage des vitesses.

The targeted applications are:

• Computer applications: mouse, joystick
• Industrial applications: pick and place
• Automotive applications: assistance with shifting.

Figures 1 and 2 show views of a first embodiment of an XY linear actuator.

The objective is to move a movable part in a 2-axis plane comprising at the base a structure composed of a 4-pole stator, a movable magnet and a yoke that can be fixed or movable with the magnet .

The first version presented with reference to Figures 1 and 2 relates to an actuator with fixed yoke. In this architecture, only the magnet (14) is mobile.

• 1 aimant plat (14) composé d'une nuance d'aimant isotrope ou axialement anisotrope. Dans ce dernier cas, le sens de l'anisotropie devra être perpendiculaire à la surface des pôles. Il sera aimanté dans cette même direction.
• 1 culasse (5) en matériau magnétique à haute perméabilité
• 1 stator composé d'une base plane (6) et de 4 pôles (1 à 4) de section rectangulaire. Il sera également réalisé en matériau magnétique à haute perméabilité
• 4 bobines (7 à 10), chacune entourant l'un des pôles du stator

The actuator is then composed of the following functional parts:

• 1 flat magnet (14) composed of an isotropic magnet or axially anisotropic magnet. In the latter case, the direction of the anisotropy must be perpendicular to the surface of the poles. He will be magnetized in this same direction.
• 1 cylinder head (5) of high permeability magnetic material
• 1 stator composed of a flat base (6) and 4 poles (1 to 4) of rectangular section. It will also be made of magnetic material with high permeability
• 4 coils (7 to 10), each surrounding one of the stator poles

Possibly a magnet support coming surround the magnet to transmit the effort - or displacement - provided to an external part.

For the latter, any form can be imagined.

The operation of this actuator can be explained as follows, with reference to FIGS. 3a and 3b:

If one imposes the same current il in the coils (7) and (8) and a current i2 in the coils (9) and (10), one creates a potential difference along the axis X: one thus creates a Fx force along the X axis proportional to the magnetic potential difference created.

In the same way, if a current i3 is imposed in the coils (7) and (9) and a current i4 in the coils (8) and (10), a force Fy is created proportional to the magnetic potential difference. , collinear with the Y axis.

That being established, it follows that the composition of the so-called currents will enable us, by the superposition principle, to create any force whose direction will be included in this XY plane.

• si en alimentant (7) et (8) par un courant il et en alimentant (9) et (10) par un courant i2, on crée une force Fx
• si en alimentant (7) et (9) par un courant i3 et en alimentant (8) et (10) par un courant i4, on crée une force Fy

Indeed :

• if by feeding (7) and (8) by a current il and feeding (9) and (10) by a current i2, a force Fx is created
• if by feeding (7) and (9) by a current i3 and feeding (8) and (10) by a current i4, a force Fy is created

Then, by feeding (7) by i1 + i3, (8) by i1 + i4, (9) by i2 + i3 and (10) by i2 + i4, we create a force Fx + Fy.

This actuator thus makes it possible to create an adjustable intensity and direction force in the plane (XY).

Let L be the thickness of the magnet, E the air gap, C _x and C _y the sensor strokes in both dimensions and d _x and d _y the distances from pole to pole along the 2 axes.

It is advisable to use an E / E ratio between 1 and 2.

If we take as dimensions of the magnet (C _x + E + d _x ) and (C _y + E + d _y ) and for minimum dimensions of the stator poles (C _x + E) and (C _y + E) in the measurement plane, the linearity of the force as a function of the current will be effective on both axes.

Another architecture of this actuator can be imagined according to the variant shown in FIGS. 4 and 5.

• 1 aimant plat (14), de forme rectangulaire, composé d'une nuance d'aimant isotrope ou axialement anisotrope. Dans ce dernier cas, le sens de l'anisotropie devra être perpendiculaire à la surface des pôles. Il sera aimanté dans cette même direction.
• 1 stator X (20) en matériau magnétique à haute perméabilité composé d'une base plane (23) et de 2 pôles (21, 22) de section rectangulaire.
• 1 stator Y (28) composé d'une base plane (25) et de 2 pôles (26, 27) aux propriétés analogues au stator X. Ces deux pôles (26, 27) sont orientés perpendiculairement aux pôles (21, 22) du stator X
• 2 bobines X (31, 32), chacune entourant l'un des pôles (21, 22) du stator X
• 2 bobines Y (36, 37), chacune entourant l'un des pôles (26, 27) du stator Y.

The actuator is then composed of the following functional parts:

• 1 flat magnet (14), of rectangular shape, composed of an isotropic magnet or axially anisotropic magnet. In the latter case, the direction of the anisotropy must be perpendicular to the surface of the poles. He will be magnetized in this same direction.
• 1 stator X (20) of high permeability magnetic material composed of a plane base (23) and 2 poles (21, 22) of rectangular section.
• 1 stator Y (28) composed of a plane base (25) and 2 poles (26, 27) with properties similar to the stator X. These two poles (26, 27) are oriented perpendicular to the poles (21, 22) of the stator X
• 2 X coils (31, 32), each surrounding one of the poles (21, 22) of the stator X
• 2 Y coils (36, 37), each surrounding one of the poles (26, 27) of the stator Y.

The coils are flat coils surrounding each of the stator poles.

Possibly a magnet support surrounding the magnet to transmit the effort - or displacement - provided to an external part.

The stator X and the stator Y are arranged on both sides of the main air gap in which the magnet (14) is placed. The poles (21, 22) of the stator X are oriented perpendicularly to the poles (26, 27) of the stator Y, in order to drive the moving magnet in both perpendicular directions and to provide a bidirectional displacement of the member to which it is coupled.

The operation of this version can be explained as follows:

If we impose a current il in the coil (31) and a current i2 in the coil (32), we create a potential difference along the X axis and thus creates a force Fx along the X axis proportional to the magnetic potential difference created.

In the same way, if a current i3 is imposed in the coil (36) and a current i4 in the coil (37), a force Fy is created proportional to the magnetic potential difference, collinear with the axis Y.

By combining the control of the currents in the coils (X) and in the coils (Y) independently of one another, it will be possible to create an adjustable force in amplitude and direction in the XY plane.

Figures 6 and 7 show schematic views respectively in a transverse view, and the stator portion of a first embodiment in the form of an XY linear actuator. This variant of the actuator has the advantage of requiring only one coil per axis.

• 1 aimant plat (14) composé d'une nuance d'aimant isotrope ou axialement anisotrope. Dans ce dernier cas, le sens de l'anisotropie devra être perpendiculaire à la surface des pôles. Il sera aimanté dans cette même direction.
• 1 culasse (40) constitué par une plaque en un matériau magnétique à haute perméabilité
• 1 stator (41) composé de 4 pôles (42 à 45) de section rectangulaire reliés par des noyaux autour desquels seront enroulées les bobines (46, 47). Il sera également réalisé en matériau magnétique à haute perméabilité. Il est constitué dans l'exemple décrit par un bloc parallélépipèdique, présentant des rainures médianes perpendiculaires pour le positionnement des bobines et délimitant les pôles statoriques (42 à 45)
• 2 bobines croisées (46, 47), entourant le stator (41) dans deux directions perpendiculaires.

The actuator is then composed of the following functional parts:

• 1 flat magnet (14) composed of an isotropic magnet or axially anisotropic magnet. In the latter case, the direction of the anisotropy must be perpendicular to the surface of the poles. He will be magnetized in this same direction.
• 1 cylinder head (40) consisting of a plate made of a material high permeability magnetic
• 1 stator (41) composed of 4 poles (42 to 45) of rectangular section connected by cores around which the coils (46, 47) will be wound. It will also be made of magnetic material with high permeability. It is constituted in the example described by a parallelepiped block, having perpendicular median grooves for the positioning of the coils and delimiting the stator poles (42 to 45)
• 2 crossed coils (46, 47), surrounding the stator (41) in two perpendicular directions.

Possibly a magnet support surrounding the magnet to transmit the effort or displacement provided to an external part.

The operation of this version can be explained as follows:

If we impose a current il in the coil (46), we create a potential difference along the X axis and thus creates a force Fx along the X axis proportional to the magnetic potential difference created, so the current he.

In the same way, if a current i2 is imposed in the coil (47), a force Fy is created proportional to the magnetic potential difference and therefore to the current i2, collinear with the axis Y.

It is then easily understood that by combining the steering currents in the coils (46) and in the coils (47) independently of one another, we can create a force adjustable in amplitude and direction in the XY plane.

This variant can also be made symmetrical, that is to say by replacing the cylinder head with a stator + coils. We will then increase the amplitude of the created force.

It is also possible to make the stator several distinct parts, for example by separating the poles. We can then obtain a kernel-free version of ferromagnetic coil or with independent coil cores, which would facilitate winding.

This variant can also be made in symmetrical version.

Figures 8 and 9 show a variant of a cylindrical actuator x-θ, respectively without and with the magnet. Several versions can be imagined. The actuator has a cylindrical structure, thus comprising an area inside the magnet and an area outside the same magnet. This structure fulfills two functions to ensure: rotary actuator function and linear actuator. The solutions defined below will be defined by the situation ("inside" or "outside") of each of these functions. In general, the actuator comprises a stator structure having four poles (51 to 54) in the form of half-cylinders and a tubular magnet (55).

The description which follows will firstly present an actuator of the "Linear and Rotary Inner" type.

A first solution is described in Figures 10 to 12: it consists of the use of a cylindrical internal stator composed of four identical poles. Two coils are surrounded around each of these poles.

• 1 demi-aimant bague (60) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci pourra être indépendant ou collé à la culasse (61)
• 1 culasse bague (61) en matériau magnétique à haute perméabilité
• 1 stator composé de 4 pôles (62 à 65) de forme extérieure cylindrique reliés par des noyaux (70, 71) autour desquels seront enroulées les bobines (66 à 69). Il sera également réalisé en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, il pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques
• • 4 bobines (66 à 69), entourant le stator.

The actuator is then composed of the following functional parts:

• 1 half-magnet ring (60) composed of an isotropic magnet or radially anisotropic magnet, radially magnetized. It may be independent or glued to the breech (61)
• 1 ring yoke (61) made of magnetic material with high permeability
• 1 stator composed of 4 poles (62 to 65) of cylindrical outer shape connected by cores (70, 71) around which the coils (66 to 69) will be wound. It will also be made of magnetic material with high permeability. Depending on the manufacturing preference, it can be made of a single piece or an assembly of ferromagnetic parts
• • 4 coils (66 to 69), surrounding the stator.

The operation of this actuator can be explained as follows:

If one imposes the same current il in the coils (66) and (67) and a current i2 in the coils (68) and (69), one creates a potential difference along the axis X and one thus creates a Fx force along the X axis proportional to the magnetic potential difference created.

In the same way, if a current i3 is imposed in the coils (66) and (68) and a current i4 in the coils (67) and (69), this time a moment of rotation MX is generated on the collinear magnet to the x-axis and proportional to the magnetic potential difference created.

That being established, it follows that the composition of these currents will allow us, by the superposition principle, to create any set "force - moment" direction collinear to the X axis.

• si en alimentant (66) et (67) par un courant il et en alimentant (68) et (69) par un courant i2 , on crée une force Fx
• si en alimentant (66) et (68) par un courant i3 et en alimentant (67) et (69) par un courant i4, on crée un moment Mx

Indeed :

• if by supplying (66) and (67) by a current I1 and feeding (68) and (69) by a current i2, a force Fx is created
• if by feeding (66) and (68) by a current i3 and feeding (67) and (69) by a current i4, a moment Mx is created

Then, by feeding (66) by il + i3, (67) by it + i4, (68) by i2 + i3 and (69) by i2 + i4, one creates a force Fx and a moment Mx

This actuator makes it possible to create at the same time a force and a moment of adjustable intensities, both collinear with the X axis.

Figures 13 to 16 show a second solution of a linear-rotary actuator.

This second solution consists in replacing 2 of the 4 coils of the preceding solution by a coil mounted on the main axis of the mechanism. This one, named (4L), will assure the part "axial force" and the 2 others will create the moment.

• 1 demi-aimant bague (60) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci pourra être indépendant ou collé à la culasse.
• 1 culasse bague (61) en matériau magnétique à haute perméabilité
• 1 stator composé de 4 pôles (62 à 65) de forme extérieure cylindrique. Les demi-lunes situées en vis-à-vis radial sont reliés 2 à 2 par des noyaux (70, 71) autour desquels seront enroulées les bobines (4R). Les ensembles ainsi constitués seront reliés par un noyau axial (72) autour duquel sera enroulée la bobine (4L). Tous ces pôles seront également réalisés en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, il pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques (cf. figure 16).
• 2 bobines longitudinales (4R)
• 1 bobine transversale (4L)

The actuator is then composed of the following functional parts:

• 1 half-magnet ring (60) composed of an isotropic magnet or radially anisotropic magnet, radially magnetized. It may be independent or stuck to the breech.
• 1 ring yoke (61) made of magnetic material with high permeability
• 1 stator composed of 4 poles (62 to 65) of cylindrical outer shape. The half-moons located opposite each other are connected 2 to 2 by cores (70, 71) around which the coils (4R) will be wound. The assemblies thus formed will be connected by an axial core (72) around which the coil (4L) will be wound. All these poles will also be made of magnetic material with high permeability. Depending on the manufacturing preference, it can be made of a single piece or an assembly of ferromagnetic parts (see Figure 16).
• 2 longitudinal coils (4R)
• 1 transverse coil (4L)

Possibly a magnet support surrounding the magnet to transmit the effort - or displacement - provided to an external part.

The operation of this actuator can be explained as follows:

If one imposes the current il in the coil (4L), one creates a magnetic potential difference along the X axis: one thus creates a force Fx along the X axis proportional to the magnetic potential difference created.

In the same way, if a current i2 is imposed on the coils (4R), this time a moment of rotation Mx is created on the magnet collinear with the axis X and proportional to the magnetic potential difference created.

This actuator thus makes it possible to create both a force and a moment of adjustable intensities, both collinear with the axis X.

Figures 17 to 19 show a third version of a linear-rotary actuator. The stator is formed by a cylindrical piece having 4 poles (62 to 65) in the form of half-cylinders. In this solution, the 2 previously noted coils (4R) are replaced by one and the same coil. We then have in all and for all 2 crossed coils, as illustrated in Figures 17 to 19.

The operation of this actuator can. be explained as follows:

If a current il is imposed in the coil (4L), a magnetic potential difference is created along the X axis: a force Fx is thus created along the X axis proportional to the magnetic potential difference created.

In the same way, if a current i2 is imposed on the coil (4R), this time a moment of rotation Mx is created on the magnet collinear with the axis X and proportional to the magnetic potential difference created.

This actuator thus makes it possible to create both a force and a moment of adjustable intensities, both collinear with the axis X.

Another structure could also be obtained by splitting the coil (4L) into 3 or 4 coils coming to be mounted on either side of the axial poles.

Figures 20 and 21 show an alternative embodiment of an actuator type "linear and rotary exterior".

All the versions presented in this part are in fact homologous versions of the versions presented in the previous part: we only reverse the inner and outer parts. They will nevertheless be presented for the sake of clarity.

In the version shown in Figures 20 and 21, there are four outer coils, each of them surrounding a pole.

• 1 demi-aimant bague (80) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci pourra être indépendant ou collé à la culasse
• 1 culasse cylindrique (81) en matériau magnétique à haute perméabilité
• 1 stator composé de 4 pôles (82 à 85) de forme intérieure cylindrique reliés par une base commune. Il sera également réalisé en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, il pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques.
• 4 bobines (86 à 89), entourant les pôles statoriques respectivement (82 à 85)

The actuator is then composed of the following functional parts:

• 1 half-magnet ring (80) composed of an isotropic magnet or radially anisotropic magnet, radially magnetized. It can be independent or stuck to the breech
• 1 cylindrical cylinder head (81) of high permeability magnetic material
• 1 stator composed of 4 poles (82 to 85) of cylindrical inner shape connected by a common base. It will also be made of magnetic material with high permeability. Depending on the manufacturing preference, it can be made of a single piece or an assembly of ferromagnetic parts.
• 4 coils (86 to 89), surrounding the stator poles respectively (82 to 85)

Possibly a magnet support surrounding the magnet to transmit the effort - or displacement - provided to an external part.

This version works similarly to the version shown with reference to FIGS. 10 to 12:

Indeed, by feeding (86) by i1 + i3, (87) by i1 + i4, (88) by i2 + i3 and (89) by i2 + i4, we create a force Fx and a moment Mx

This actuator thus makes it possible to create both a force and a moment of adjustable intensities, both collinear with the axis X.

Figures 22 and 23 show a second version of a "linear-rotary" type actuator.

• 1 demi-aimant bague (90) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci pourra être indépendant ou collé à la culasse.
• 1 culasse cylindrique (95) en matériau magnétique à haute perméabilité
• 1 stator composé de 4 pôles (91 à 94) et d'une structure (96) commune. Autour des pôles (91, 92) seront enroulées les bobines (4R) (97, 98). La bobine (4L) sera située entre les pôles comme montré sur la figure 22. Tous ces pôles (91 à 94) seront également réalisés en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, l'ensemble pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques
• 2 bobines (4R)
• 1 bobine (4L)

The actuator is then composed of the following functional parts:

• 1 half-magnet ring (90) composed of an isotropic magnet or radially anisotropic magnet, magnetized radially. It may be independent or stuck to the breech.
• 1 cylinder head (95) of high permeability magnetic material
• 1 stator composed of 4 poles (91 to 94) and a common structure (96). Around the poles (91, 92) will be wound the coils (4R) (97, 98). The coil (4L) will be located between the poles as shown in Figure 22. All these poles (91 to 94) will also be made of magnetic material with high permeability. Depending on the manufacturing preference, the assembly can be made of a single piece or an assembly of ferromagnetic parts
• 2 coils (4R)
• 1 reel (4L)

The operation of this actuator can be explained as follows:

If one imposes the current il in the coil (4L), one creates a magnetic potential difference along the X axis: one thus creates a force Fx along the X axis proportional to the magnetic potential difference created.

In the same way, if we impose a current i2 in the coils (4R), this time creates a moment of rotation Mx on the magnet collinear with the X axis and proportional to the magnetic potential difference created.

This actuator thus makes it possible to create both a force and a moment of adjustable intensities, both collinear with the axis X.

The coils (4L) and (4R) are shown here of rectangular shape to facilitate the reading of the drawing, but it goes without saying that they could also, for example, take a cylindrical shape.

It is also possible, in order to increase the torque, to have 4 coils (4R), by placing 2 on the 2 unused stator poles.

• 1 demi-aimant bague (90) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci pourra être indépendant ou collé à la culasse.
• 1 culasse cylindrique (95) en matériau magnétique à haute perméabilité
• 1 stator composé de 4 pôles (91 à 94) et d'une structure (96) commune. Autour de 2 d'entre eux sera enroulée la bobine (4R). La bobine (4L) sera située entre les pôles (91 à. 94). Tous ces pôles seront également réalisés en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, il pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques.
• 1 bobine (4R)
• 1 bobine (4L)

Figures 24 and 25 show a third version of a "linear-rotary" type actuator, having two crossed coils. The actuator according to this third version is composed of the following functional parts:

• 1 half-magnet ring (90) composed of an isotropic magnet or radially anisotropic magnet, magnetized radially. It may be independent or stuck to the breech.
• 1 cylinder head (95) of high permeability magnetic material
• 1 stator composed of 4 poles (91 to 94) and a common structure (96). Around 2 of them will be wound the coil (4R). The coil (4L) will be located between the poles (91 to 94). All these poles will also be made of magnetic material with high permeability. Depending on the manufacturing preference, it can be made of a single piece or an assembly of ferromagnetic parts.
• 1 reel (4R)
• 1 reel (4L)

Possibly a magnet support surrounding the magnet to transmit the effort - or displacement - provided to an external part.

The operation of this actuator can be explained as follows:

If a current i1 is imposed on the coil (4L), a magnetic potential difference is created along the X axis: a force Fx is thus created along the X axis proportional to the magnetic potential difference created.

In the same way, if a current i2 is imposed on the coil (4R), this time a moment of rotation Mx is created on the magnet collinear with the axis X and proportional to the magnetic potential difference created.

This actuator thus makes it possible to create both a force and a moment of adjustable intensities, both collinear with the axis X.

Another structure could also be obtained by splitting the coil (4L) into 3 or 4 coils coming to be mounted on either side of the axial poles, or by adding a second coil (4R), symmetrically to the first with respect to the 'axis.

Finally, for each of these versions, another structure could also be obtained by multiplying the stator structure by the use of several stators. This gives a structure with more external poles, with several magnets, which offers a lower angular stroke but a larger torque. One can thus imagine any structure with (2N) radial poles spaced angularly from (360 ° / 2N), with N magnets.

• 1 demi-aimant bague (100) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci devra être indépendant des deux stators.
• 1 stator cylindrique en matériau magnétique à haute perméabilité, composé de deux pôles (101, 102) de même diamètre. La bobine (103) sera située entre ces deux pôles, autour d'un noyau ferromagnétique.
• 1 stator composé de 2 pôles (104, 105) et d'une structure commune (108). Autour d'eux seront enroulées les bobines (106, 107). Ces pôles (104, 105) seront également réalisés en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, ce stator pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques.
• 1 bobine (106)
• bobine (107)

FIG. 26 represents a first version of a variant of the type "Linear internal, external rotary". The actuator is then composed of the following functional parts:

• 1 half-magnet ring (100) composed of an isotropic magnet or radially anisotropic magnet, magnetized radially. This one will have to be independent of the two stators.
• 1 cylindrical stator of magnetic material with high permeability, composed of two poles (101, 102) of the same diameter. The coil (103) will be located between these two poles, around a ferromagnetic core.
• 1 stator composed of 2 poles (104, 105) and a common structure (108). Around them will be rolled the coils (106, 107). These poles (104, 105) will also be made of magnetic material with high permeability. According to the manufacturing preferences, this stator can be made of a single piece or an assembly of ferromagnetic parts.
• 1 spool (106)
• coil (107)

Possibly a magnet support surrounding the magnet to transmit the effort - or displacement - provided to an external part.

The operation of this actuator can be explained as follows:

If a current il is imposed in the coil (103), a magnetic potential difference is created along the X axis: a force Fx is thus created along the X axis proportional to the magnetic potential difference created.

In the same way, if a current i2 is imposed in the coils (106, 107), this time a moment of rotation Mx is created on the magnet collinear with the axis X and proportional to the magnetic potential difference created. .

This actuator thus makes it possible to create both a force and a moment of adjustable intensities, both collinear with the axis X.

Another structure could also be obtained by multiplying the outer stator structure according to FIG. 27. This gives a structure with more external poles (110, 111, 112, 113), with several magnets (115, 116), which offers a lower angular stroke but a larger torque. One can thus imagine any structure with (2N) radial poles. This multiplication principle can also be applied to each cylindrical structure described in this text.

• 1 demi-aimant bague (120) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci devra être indépendant des deux stators.
• 1 stator cylindrique en matériau magnétique à haute perméabilité, composé de deux pôles (121, 122) de même diamètre. La bobine (125) sera située autour de ce stator, entre les 2 pôles (121, 122).
• 1 stator composé de 2 pôles (123, 124) et d'une structure commune. La bobine (126) entoure ce stator, entre les 2 pôles (123, 124). Ces pôles seront également réalisés en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, ce stator pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques.
• 1 bobine (125)
• 1 bobine (126)

Another structure could also be obtained by using only one coil for the creation of a moment of rotation. Figures 28 and 29 show views of three quarter face and section of such a version. This consists of a new arrangement of the outer part of the actuator allowing to have only 2 coils. The actuator is then composed of the following functional parts:

• 1 half-magnet ring (120) composed of an isotropic magnet or radially anisotropic magnet, magnetized radially. This one will have to be independent of the two stators.
• 1 cylindrical stator made of magnetic material with high permeability, composed of two poles (121, 122) of the same diameter. The coil (125) will be located around this stator, between the two poles (121, 122).
• 1 stator composed of 2 poles (123, 124) and a common structure. The coil (126) surrounds this stator, between the two poles (123, 124). These poles will also be made of magnetic material with high permeability. According to the manufacturing preferences, this stator can be made of a single piece or an assembly of ferromagnetic parts.
• 1 roll (125)
• 1 spool (126)

Possibly a magnet support coming surround the magnet to transmit the effort - or displacement - provided to an external part.

The operation of this actuator can be explained as follows:

If a current i1 is imposed on the coil (125), a magnetic potential difference is created along the X axis: a force Fx is thus created along the x axis proportional to the magnetic potential difference created.

In the same way, if a current i2 is imposed on the coil (126), this time a moment of rotation Mx is created on the magnet collinear with the axis X and proportional to the magnetic potential difference created.

This actuator thus makes it possible to create both a force and a moment of adjustable intensities, both collinear with the axis X.

Figures 30 and 31 describe an actuator of the type "Linear outside, rotating inside".

• 1 demi-aimant bague (140) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci devra être indépendant des deux stators.
• 1 stator cylindrique en matériau magnétique à haute perméabilité, composé de deux pôles (141, 142) de même diamètre. La bobine (143) sera située entre les 2 pôles.
• 1 stator (2R) composé de 2 pôles (144, 145) et d'un noyau commun. La bobine (146) sera située entouré autour de ce noyau, entre les 2 pôles (144, 145). Ces pôles seront également réalisés en matériau magnétique à haute perméabilité
• 1 bobine (143)
• 1 bobine (146)

The actuator is composed of the following functional parts:

• 1 half-magnet ring (140) composed of an isotropic magnet or radially anisotropic magnet, magnetized radially. This one will have to be independent of the two stators.
• 1 cylindrical stator of magnetic material with high permeability, composed of two poles (141, 142) of the same diameter. The coil (143) will be located between the 2 poles.
• 1 stator (2R) composed of 2 poles (144, 145) and a common core. The coil (146) will be located around this core, between the two poles (144, 145). These poles will also be made of magnetic material with high permeability
• 1 roll (143)
• 1 spool (146)

Possibly a magnet support surrounding the magnet to transmit the effort - or displacement - provided to an external part.

The operation of this actuator can be explained as follows:

If a current il is imposed in the coil (143), a magnetic potential difference is created along the X axis: a force Fx is thus created along the X axis proportional to the magnetic potential difference created.

In the same way, if a current i2 is imposed in the coil (146), this time a moment of rotation Mx is created on the collinear magnet at the x axis and proportional to the magnetic potential difference created.

This actuator thus makes it possible to create both a force and a moment of adjustable intensities, both collinear with the axis X.

Note that by making the stator in the form of four quarters of cylinders (150 to 153) around which surround two coils (154, 155) (see Figure 32), we obtain a 4-pole rotary version, reduced stroke at less than 90 ° but providing a larger torque. We will then have 2 magnets of 90 ° angular width.

Figures 33 and 34 show views of a spherical actuator α-β and its stator.

Several versions can be imagined. The solutions defined below will be defined by the situation ("inside" or "outside") of the two functions (rotation around 2 axes) provided by the actuator.

• 1 demi -aimant sphérique (200) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci pourra être indépendant ou collé à la culasse, ainsi que montré sur la figure (33).
• 1 culasse sphérique creuse (201) en matériau magnétique à haute perméabilité
• 1 stator composé de 4 pôles (202 à 205) de forme extérieure sphérique reliés par des noyaux autour desquels seront enroulées les quatre bobines (206 à 209). Il sera également réalisé en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, il pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques.
• 4 bobines (206 à 209), entourant le stator

The actuator is composed of the following functional parts:

• 1 spherical half-magnet (200) composed of a shade Isotropic magnet or radially anisotropic, magnetized radially. This may be independent or glued to the cylinder head, as shown in Figure (33).
• 1 hollow spherical yoke (201) made of magnetic material with high permeability
• 1 stator composed of 4 poles (202 to 205) of spherical outer shape connected by cores around which will be wound the four coils (206 to 209). It will also be made of magnetic material with high permeability. Depending on the manufacturing preference, it can be made of a single piece or an assembly of ferromagnetic parts.
• 4 coils (206 to 209), surrounding the stator

Possibly a magnet support being attached to the magnet for transmitting the effort - or displacement - supplied to an external part.

The operation of this actuator can be explained as follows:

If one imposes the same current il in the coils (206) and (208), one creates a potential difference following a rotation around the axis X and one thus creates a moment Mx according to the proportional axis X unlike magnetic potential created.

In the same way, if a current i2 is imposed on the coils (207) and (209), this time a moment of rotation My is created on the magnet collinear with the axis Y and proportional to the potential difference. magnetic created.

The composition of these currents will allow us, by the principle of superposition, to create any moment whose axis will be included in this plane XY.

• En alimentant (206) et (208) par un courant i1, on crée un moment Mx
• En alimentant (207) et (209) par un courant i2, on crée un moment My

Indeed :

• By feeding (206) and (208) by a current i1, we create a moment Mx
• By feeding (207) and (209) by a current i2, we create a moment My

Then, by feeding (206) and (208) by i1, (207) and (209) by i2, we create a moment Mx and a moment My.

This actuator thus makes it possible to create independent pairs along two orthogonal axes.

• 1 demi-aimant sphérique (210) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci pourra être indépendant ou collé à la culasse, ainsi que montré sur la figure (35).
• 1 culasse sphérique creuse (211) en matériau magnétique à haute perméabilité
• 1 stator composé de 4 pôles (212 à 215) de forme extérieure sphérique reliés par des noyaux autour desquels seront enroulées les bobines (216, 217). Il sera également réalisé en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, il pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques.
• 2 bobines (216), et (217), croisées, entourant le stator

Fig. 35 shows a second version of a spherical actuator. The actuator is composed of the following functional parts:

• 1 spherical half-magnet (210) composed of an isotropic magnet or radially anisotropic magnet, magnetized radially. This may be independent or glued to the cylinder head, as shown in Figure (35).
• 1 hollow spherical yoke (211) of high permeability magnetic material
• 1 stator composed of 4 poles (212 to 215) of spherical outer shape connected by cores around which the coils (216, 217) will be wound. It will also be made of magnetic material with high permeability. Depending on the manufacturing preference, it can be made of a single piece or an assembly of ferromagnetic parts.
• 2 coils (216), and (217), crossed, surrounding the stator

Possibly a magnet support being attached to the magnet for transmitting the effort - or displacement - supplied to an external part.

The operation of this actuator can be explained as follows:

If one imposes a current il in the coil (216), one creates a potential difference following a rotation around the axis X and one thus creates a moment Mx along the X axis proportional to the magnetic potential difference created.

In the same way, if a current i2 is imposed in the coil (217), this time a rotation moment My is created on the magnet collinear with the axis Y and proportional to the magnetic potential difference created.

The composition of these currents will allow us, by the principle of superposition, to create any moment whose axis will be included in this plane XY.

Figure 36 corresponds to another arrangement of the same system, more easily achievable industrially but at a lower stroke.

The stator parts are made in quarter-shaped spherical sector (220 to 223). They are surrounded by two coils (224, 225).

FIGS. 37 and 38 show views of a spherical actuator of the "all exterior" type:

The principle of this solution is to reverse the architecture of the previous actuator, putting the yoke and the magnet inside, the stator poles outside.

• 1 aimant en forme de calotte sphérique (230) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement.
• 1 culasse sphérique (231) en matériau magnétique à haute perméabilité
• 1 stator composé de 4 pôles (232 à 235) de forme extérieure en quart de cylindre et de forme intérieure sphérique reliés par des noyaux autour desquels seront enroulées les bobines (236 à 239). Il sera également réalisé en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, il pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques.
• 4 bobines (236 à 239), entourant le stator, 2 par axe de rotation

The first version of the actuator is composed of the following functional parts:

• 1 spherical cap-shaped magnet (230) composed of an isotropic magnet or radially anisotropic magnet, magnetized radially.
• 1 spherical yoke (231) of magnetic material with high permeability
• 1 stator composed of 4 poles (232 to 235) of outer quarter-cylindrical shape and spherical inner shape connected by cores around which will be wound the coils (236 to 239). It will also be made of magnetic material with high permeability. Depending on the manufacturing preferences, it may be made of a single piece or assembly of ferromagnetic parts.
• 4 coils (236 to 239), surrounding the stator, 2 per axis of rotation

Possibly a magnet support being attached to the magnet for transmitting the effort - or displacement - supplied to an external part.

The operation of this actuator is in all respects the same as that of the first spherical actuator presented in this text.

Figures 39 and 40 show a second version of an "all-out" type spherical actuator.

• 1 aimant en forme de calotte sphérique (250) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement.
• 1 culasse sphérique (251) en matériau magnétique à haute perméabilité
• 1 stator composé de 4 pôles (252 à 255) de forme intérieure sphérique reliés par des noyaux autour desquels seront enroulées les bobines (256, 257). Il sera également réalisé en matériau magnétique à haute perméabilité. Selon les préférences de fabrication, il pourra être fait d'une seule pièce ou d'un assemblage de pièces ferromagnétiques.
• 2 bobines (256, 257), entourant le stator, 1 par axe de rotation

The actuator is composed of the following functional parts:

• 1 spherical cap-shaped magnet (250) composed of an isotropic magnet or radially anisotropic magnet, magnetized radially.
• 1 spherical yoke (251) of magnetic material with high permeability
• 1 stator composed of 4 poles (252 to 255) of spherical inner shape connected by cores around which the coils (256, 257) will be wound. It will also be made of magnetic material with high permeability. Depending on the manufacturing preference, it can be made of a single piece or an assembly of ferromagnetic parts.
• 2 coils (256, 257), surrounding the stator, 1 per axis of rotation

The operation of this actuator is in all respects the same as that of the spherical actuator shown in FIGS. 35 and 36.

Figures 41 and 42 show views of three quarter face and partial section of a hybrid actuator (indoor & outdoor).

• 1 aimant en forme de calotte sphérique (260) composé d'une nuance d'aimant isotrope ou radialement anisotrope, aimanté radialement. Celui-ci devra être indépendant des deux stators
• 1 stator intérieur, de formes extérieures sphériques, en matériau magnétique à haute perméabilité. Il présente 2 pôles (261, 262) reliés par un noyau autour duquel est enroulée la bobine (265).
• 1 stator extérieur composé de 2 pôles (263, 264) de forme intérieure sphérique reliés par un noyau autour duquel sera enroulée la bobine (266). Il sera également réalisé en matériau magnétique à haute perméabilité.
• 1 bobine (266), entourant le stator extérieur
• 1 bobine (265), entourant le stator intérieur

The actuator is composed of the following functional parts:

• 1 spherical cap-shaped magnet (260) composed of an isotropic magnet or radially anisotropic magnet, magnetized radially. This one must be independent of the two stators
• 1 inner stator, spherical outer shapes, made of magnetic material with high permeability. It has 2 poles (261, 262) connected by a core around which is wound the coil (265).
• 1 outer stator composed of 2 poles (263, 264) of spherical inner form connected by a core around which the coil (266) will be wound. It will also be made of magnetic material with high permeability.
• 1 coil (266), surrounding the outer stator
• 1 coil (265), surrounding the inner stator

Possibly a magnet support being attached to the magnet for transmitting the effort - or displacement - supplied to an external part.

The operation of this actuator can be explained as follows:

If a current il is imposed in the coil (266), a potential difference is created following a rotation around the axis X and thus a moment Mx is created along the X axis proportional to the potential difference. magnetic created.

In the same way, if a current i2 is imposed on the coil (265), this time a moment of rotation My is created on the magnet collinear with the axis Y and proportional to the magnetic potential difference created.

The composition of these currents will allow us, by the principle of superposition, to create any moment whose axis will be included in this plane XY.

Each of the above electromagnetic systems may be coupled with non-contact dimensional position sensors.

We will then obtain a set "sensor - actuator" to ensure two functions in the same volume and thus work in closed loop.

For this, it will be necessary to separate the iron parts between the poles of the stators (namely those around which one comes to surround the coils, generally called "core" throughout this patent) by means of a slot.

An element sensitive to magnetic fields (for example a Hall effect probe) will then be positioned in the said slot.

Figures 43 and 44 illustrate the application of this principle to a planar XY actuator.

The position sensor makes it possible to measure the variations of flux created by a moving magnet in an air gap.

The stator consists of four rectangular portions (300 to 303) surrounded by four coils (310 to 313). A thin magnet (305) transversely magnetized is placed in the main gap (307) formed between the stator and the yoke (306). Four Hall probes (320 to 323) are placed in the secondary air gaps between the stator parts (300 to 303).

In the architecture described, the probes will measure a variation of flux due to the displacement of the magnet and the current flowing in the coils. We must therefore "discard" this flow due to the current. This can be done in two ways:

By measuring the current in the coils and calculating the flow induced by the current to subtract it from the measured value. Indeed, the total flux is the sum of the flow due to the current and the flux due to the magnet (Φt = Φni + Φa = A.ni + Φa). By knowing the impedance A of the magnetic circuit and the current in the coils, it is easy to calculate Φa. The intensity can be measured by any conceivable means (for example by measuring the voltage drop across a sampling resistor through which the current flows).

By alternating the "sensor" and "actuator" functions. During a given time interval, the coils will be energized to produce the desired force (or torque), and during the next interval the supply of the coils will be suppressed so that only the flux due to the magnet will be measured. We will have an intermittent force that can be used for joystick type functions.

Claims (15)

1. Two-directional actuator comprising at least one stator structure excited by at least one electrical coil, characterised in that it comprises a single mobile magnet placed in a main air gap and in that the stator structure comprises at least one electrical coil, and is composed of a first pair of stator poles (1, 2) defining a first secondary air gap between them, for displacement of the single mobile magnet (14) with respect to a first degree of freedom, and a second pair of the stator poles (3, 4) defining a second secondary air gap between them for displacement of the single mobile magnet (14) with respect to a second degree of freedom.
2. Two-directional actuator according to claim 1, characterised in that the mobile magnet is fixed to a yoke (25).
3. Two-directional actuator according to claim 1 or 2, characterised in that the stator structure is composed of four poles made of a soft magnetic material defining two pairs of secondary air gaps between them intersecting at a median point and in that the main air gap (10) is plane.
4. Two-directional actuator according to claim 3, characterised in that the stator poles are composed of 4 rectangular parts each surrounded by an electrical coil and defining two pairs of perpendicular secondary air gaps between them.
5. Two-directional actuator according to at least one of the previous claims, characterised in that the L/E ratio between the thickness L of the magnet and the thickness E of the air gap is between 1 and 2.
6. Two-directional actuator according to at least one of the previous claims, characterised in that the dimensions of the secondary air gaps are C₁ + E and C₂ + E, where C₁ and C₂ denote the travel distance of the mobile magnet along the two directions of the secondary air gaps and in that the magnet dimensions are C₁ + d₁ + E and C₂ + d₂ + E, where d₁ and d₂ denote the widths of the secondary air gaps.
7. Two-directional actuator according to claim 1 or 2, characterised in that the stator structure is composed of two stator parts arranged on each side of the magnet, each of the stator parts having a pair of stator poles, the pair of stator poles of one of the parts being oriented perpendicular to the pair of stator poles of the other stator part.
8. Two-directional actuator according to claim 1 or 2, characterised in that the magnet is tubular in shape and is free to move along a first degree of freedom in axial translation and a second degree of freedom in axial rotation with respect to a stator structure formed by four static poles shaped like portions of cylinders, with a first secondary air gap in the median longitudinal plane, in which at least one first electrical coil is placed surrounding at least a ferromagnetic core, and a second secondary air gap is placed in the transverse plane in which a second electrical coil surrounding a ferromagnetic core is placed.
9. Two-directional actuator according to claim 1 or 2, characterised in that the magnet is tubular in shape and is free to move along a first degree of freedom in axial translation and a second degree of freedom in axial rotation with respect to an outer cylindrical stator structure formed by four static poles with a concave surface defining the main air gap with the cylindrical yoke placed inside the magnet, each of the four stator poles being surrounded by an electrical coil.
10. Two-directional actuator according to claim 1 or 2, characterised in that the magnet is tubular in shape and is free to move along a first degree of freedom in axial translation and along a second degree of freedom in axial rotation with respect to a cylindrical stator structure formed by a first outer stator part for displacement along a first degree of freedom, and a second inner stator part for displacement along a degree of freedom, each of the stator parts comprising at least one electrical excitation coil.
11. Two-directional actuator according to claim 1 or 2, characterised in that the magnet is spherical in shape and is free to move in spherical rotation about a stator structure shaped like a spherical cap formed from four stator poles shaped like a cap sector, comprising two coils housed in peripheral grooves, with perpendicular median planes.
12. Two-directional actuator according to claim 1 or 2, characterised in that the magnet is spherical in shape and is free to move in spherical rotation about a stator structure that is tubular in shape formed from four stator poles shaped like a quarter of a tube surrounded by an electrical coil.
13. Two-directional actuator according to claim 11, characterised in that the main air gap is spherical in shape.
14. Two-directional actuator according to claim 1 or 2, characterised in that the magnet is spherical in shape and is surrounded by a spherical yoke, and is free to move in spherical rotation about a spherical or hemi-spherical shaped stator structure formed from four stator poles shaped like a quarter or eighth of a sphere.
15. Two-directional actuator according to claim 1 or 2, characterised in that the magnet is spherical in shape and is surrounded by a yoke formed from two hemi-spherical or quarter spherical parts, and is free to move in spherical rotation about a stator structure formed from two hemi-spherical stator parts.

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