PASSIVE HAPTIC INTERFACE

Description

DOMAINE TECHNIQUE DE L'INVENTION

[0001] The invention relates to a passive haptic interface, i.e. one that can be manipulated by the finger or hand or possibly by the foot of a user and providing a variable felt force without electrical consumption.

[0002] The present invention applies for example to an office computer control interface or a control interface inside a motorized vehicle or even a control interface for a household appliance. ETAT DE LA TECHNIQUE ANTERIEURE

[0003] Manual haptic devices are known, using a magnetic interaction between a fixed part and a mobile part, these two parts being opposite each other and each comprising either a magnet, or one comprising a magnet and the other a soft ferromagnetic element cut to form different magnetic poles.

[0004] French patent FR2908903 describes an indexing device comprising a movable control member held in at least one indexing position by a notching means. This patent describes different solutions, always providing: (a) a metallic element having protrusions, (b) a magnet or two magnets each having one pole directed towards the metallic element and a second pole directed away from the metallic element.

[0005] This solution has several drawbacks. The magnetic interaction ensuring indexing is concentrated on one (in the case of one magnet) or two teeth (in the case of two diametrically opposed magnets), which implies a fairly high and localized attractive force. The consequence is a poor torque / magnet volume ratio.

[0006] In addition, the solutions proposed by this patent face a problem of size limiting the possibilities of miniaturization: when the number of protuberances formed on the metallic element becomes significant, it is necessary to reduce the cross-section of the magnet or the pair of magnets, in order to prevent the generated magnetic field from interacting with several neighboring protuberances. But by reducing the cross-section of the magnet, torque is lost, and the indexing resistance is reduced until it is no longer perceptible. The indexing resolution is limited by the size of the interdental steps, which must be greater than the size of the magnet. These implementations therefore do not allow high indexing resolutions to be achieved.

[0007] Also known is Chinese patent CN108400046 describing a device formed by an annular surface and several static magnets arranged alternately on the annular surface and provided with at least 2 pieces of opposite moving magnets on the rotating components. The moving and static magnets are arranged sequentially to perform homopolar repulsion and heteropolar attraction.

[0008] This solution is not satisfactory because it also presents a high stiffness and a poor resolution, necessarily limited to the pitch of the magnets. Furthermore, it requires a large number of magnets to achieve a large number of notches. This solution also presents industrialization difficulties, because it requires the complex assembly of small parts.

[0009] Patent application EP1167109 describes a device for generating selection positions which comprises at least one base body which is at least partially surrounded by a housing, which carries a disc-shaped body, which is held relative to the base body by means of a magnetic base position arrangement and which is to be moved relative to the base body, and also comprises a position arrangement by means of which at least the position of the disc-shaped body relative to the housing is to be determined.It comprises at least one stator body including at least one magnetic element and a shaft guide recess, the basic body consists of a hollow rotor body which is to be moved relative to the magnetic elements and which includes at least one position indicator ring gear including at least one position indicator tooth, and a shaft element which is arranged in the shaft guide recess, and in that a discoidal body recess is provided in the housing. This embodiment allows only poor resolution because the number of notches is limited to the number of teeth which can be made, phased and aligned with the stator.

[0010] Patent WO2013023922 describes a control device comprising an actuating element with haptic feedback, this element having a touch-sensitive control surface, said actuating element being operable by an operator using a gripping member. This device comprises a first and a second flat component made of a ferromagnetic material and oriented so that their large surfaces are parallel to each other, the first flat component being able to be driven in translation in a horizontally guided manner relative to the second flat component which remains fixed, the first flat component forming the control element or transmitting its movement entirely or partially to the control element.This device also comprises a coil or an electrical conductor arranged between the flat components and assigned to a first pole shoe which is connected to the second flat component and projects relative to the first flat component. By applying a current to the coil or the conductor, it is possible to create a magnetic field by which the first flat component can, from a rest position, be driven in horizontal translation relative to the second flat component to a displacement position.

[0011] This solution is not passive but requires a power supply to the coils to power the coils.

[0012] Patent JP2016170886 discloses a device comprising a sensor comprising a first member formed by a plurality of magnetized portions at predetermined angular intervals along a circumferential direction, and a second member using the plurality of first magnets. A second magnetized portion at a predetermined angular interval along the circumferential direction is positioned so as to be able to face a magnetized portion on the outer side in the circumferential direction, and according to the rotation operation.

[0013] Patent WO2020074605 describes a magnetic rotary actuator for a motor vehicle control unit, with a stationary portion and a rotary element that can be rotated relative to the stationary portion, the magnetic rotary actuator having a magnetic locking feel that includes a plurality of magnetic locking positions, and the stationary portion and the rotary element each include at least two separately formed magnetic elements that cooperate to generate the plurality of magnetic detent positions. For each detent, only one magnet of the rotor participates in the torque, there is an asymmetry of the forces and a poor ratio between volume of magnets and torque produced.

[0014] In these devices, it is possible to give the user the sensation of passing through a succession of notches when manipulating the mobile element, the number of successive notches being determined by the number of highest magnetic polarities on each of the parts. These notches correspond to the different stable magnetic positions between the fixed and mobile parts. For example, in patent FR2908903, if the ferromagnetic part comprises 16 periodic patterns and the magnetized part comprises 2 magnets, the number of notches felt is then 16 over a complete rotation of the mobile part.

[0015] When there is a need to create a large number of notches, for example 72, over a complete rotation of the moving part (or over a given angle or linear displacement), these prior art devices have the disadvantage of requiring a large number of magnets or ferromagnetic poles. When this relatively large number of notches is coupled with a need for miniaturization, the difficulty of industrially producing the solution then becomes significant with small-sized elements that are difficult to produce due to the tight tolerances that must be maintained.

[0016] Furthermore, in many haptic devices, it is often necessary to implement a position sensor in order to be able to control the operation of a device, such as the movement of a computer pointer when the haptic interface is a mouse, or of a cursor on a dashboard screen, these examples not being limiting. Prior art devices often use optical or magnetic sensors that are simply placed near the haptic device, making the solution either bulky or uneconomical. EXPOSE DE L'INVENTION

[0017] The present invention aims to overcome the drawbacks of the state of the art by allowing a more economical industrial production of the mobile and fixed elements of a passive magnetic haptic interface, passive, that is to say that the haptic effect is obtained without electrical power supply.

[0018] To do this, the present invention proposes to produce a determined number of notches felt by the user by associating a fixed part and a mobile part, each having fewer magnetic poles than the number of notches felt, while remaining passive, that is to say without using an electric coil and without consuming electrical energy.

[0019] It is also within the object of the invention to propose a simple and economical solution for installing a position sensor in a haptic device.

[0020] More specifically, the subject of the invention is a passive haptic interface comprising a first mobile element rotating around an axis or translating along an axis, said first mobile element rotating or moving opposite a second fixed element, said first mobile element having a first plurality of magnetic poles periodically spaced apart according to a polar pitch Ps and according to the direction of movement, said second fixed element having a second plurality of magnetic poles periodically spaced apart according to a polar pitch Pr and according to the direction of movement, where Ps and Pr are different numbers from each other, a periodic force being created by the magnetic interaction between said first mobile element and second fixed element according to a period Pt characterized in that Ps and Pr are chosen such that Pt is strictly less than the smallest of the pitches Ps and Pr.

[0021] Preferably, the magnetic element consists of a single magnet having a periodically varying magnetization.

[0022] By plurality of magnetic poles is meant a significant number, greater than 4, with a regular and constant distribution.

[0023] Preferably, the number of periods of said periodic force is equal to the smallest common multiple of the numbers of periods of magnetic poles of said first mobile element and of said second fixed element.

[0024] In a variant, one of said first mobile element or second fixed element comprises a cylindrical permanent magnet having alternating North and South poles forming said first plurality of magnetic poles, the other of said first mobile element or second fixed element has a plurality of teeth connected by a crown and forming said second plurality of magnetic poles, said teeth and crown being made of a soft ferromagnetic material, said period Pt of magnetic interaction being at least twice less than the smallest of the steps Ps and Pr. Indeed, the smallest common multiple between Ps and Pr, in the case of a closed rotary embodiment, corresponds to a value at least twice greater than the total number of magnetic poles.

[0025] In another variant, said first mobile element and said second fixed element comprise a permanent magnet having alternating North and South poles forming said polar pitches Ps and Pr.

[0026] Alternatively, the second fixed element comprises a magnet having a unidirectional magnetization oriented along said axis and it comprises on either side, axially, two ferromagnetic discs (7a, 7b) made of soft iron extended radially and each by a plurality 2π / Ps of periodic teeth (42) spaced apart by said polar pitch Ps expressed in radians.

[0027] According to a variant, the second fixed element comprises a magnet having a unidirectional magnetization oriented along said axis and it comprises on either side, axially, two ferromagnetic soft iron discs extended radially and each by a plurality 2π / (2*Ps) of periodic teeth spaced apart by said polar pitch Ps multiplied by 2 and spaced between each disc by said pitch Ps expressed in radians.

[0028] According to another variant, the first mobile element comprises two discs on either side, axially, of a unipolar permanent magnet and the second fixed element comprises a disc made of a soft ferromagnetic material, said discs each being extended radially by teeth, respectively, facing radially and spaced apart by said pitch Ps.

[0029] The invention also relates to a linear passive haptic interface characterized in that said first mobile element comprises a permanent magnet magnetized transversely to the movement of said first mobile element along said axis and positioned transversely between two toothed elements made of a soft ferromagnetic material having teeth and in that the second fixed element is made of ferromagnetic material comprising teeth forming bars and extending linearly, said first fixed element moving linearly above the second fixed element.

[0030] The invention also relates to a spherical passive haptic interface characterized in that said first mobile element comprises a ball joint capable of moving in rotation around three orthogonal axes, in that said ball joint comprises a set of teeth extending radially, in that the second fixed element is formed of a plurality of fixed elements in the form of a stack of sheets of soft ferromagnetic material on either side of discrete permanent magnets oriented perpendicularly to said sheets, said sheets being extended radially by teeth facing said ball joint.

[0031] It is also within the object of the invention to enable the economical production of a haptic interface. In particular, the invention refers to a rotating haptic interface, the first mobile element comprising a ring of permanent magnets extending axially secured to a disc portion, said disc portion being extended axially in a direction opposite to said magnets by a magnetic plate used for detecting the position of said first mobile element, and the second fixed element comprising a ring made of a soft ferromagnetic material extended by teeth opposite said ring of permanent magnets.

[0032] According to a variant, said crown of magnets, said disc part and said magnetic plate are made from a single material with injected plastic binder which can become permanently magnetized.

[0033] In another variant, said disc part is made of an injected plastic binder material on which said magnetic plate is securely fixed.

[0034] Finally, said plate can be made of a plastic binder material injected onto said disc part. BREVE DESCRIPTION DES FIGURES

[0035] Other characteristics and advantages of the invention will emerge from the following reading of detailed embodiment examples, with reference to the appended figures which represent respectively: there figure 1 , a partial sectional view of a device according to a first embodiment of the invention; the figure 2 , a partial sectional view of a device according to a second embodiment of the invention; the figure 3 , a perspective view of a device according to a third embodiment of the invention; the figure 4 , a partial sectional view of a device according to a fourth embodiment of the invention; the figure 5 , a perspective view of a device according to a fifth embodiment of the invention; figure 6 , a perspective view of a device according to a sixth embodiment of the invention; figure 7 , a perspective view of a device according to a seventh embodiment of the invention; figure 8 , a perspective view of a device according to an eighth embodiment of the invention; figure 9 , a perspective view of a device according to a ninth embodiment of the invention; the figure 10 , a perspective view of a device according to an alternative embodiment of the figure 9 , according to the invention; the figure 11 , a perspective view of a device according to a linear variant of the invention; the figure 12 , a perspective view of a spherical variant embodiment of the invention, the figures 13a et 13b , two views of the same alternative embodiment of a device according to the invention, the figures 14a et 14b , two views of the same other alternative embodiment of a device according to the invention, the figure 15 , another rotating variant of the figure 4 , there figure 16 , a rotating variant that uses two permanent magnets. DESCRIPTION DETAILLEE D'UN MODE DE REALISATION

[0036] There figure 1 represents a first embodiment of a rotating haptic interface according to the invention. It comprises a first movable element (1) in the form here of a crown whose outer surface is cylindrical and can optionally be textured (not visible here) in order to improve the grip or digital actuation by a user. The inner surface of this movable element (1) has a succession of teeth (41), oriented radially relative to the axis (3) of rotation, and notches (51), defining a polar pitch Pr. This first movable element (1) is made of soft ferromagnetic material, for example steel or an iron alloy. Inside this first movable element (1) and facing, radially, the first movable element (1) is positioned a second fixed element (2). The latter comprises a permanent magnet (6) in the form of a disc whose magnetization is directed axially.On either side of this magnet (6), axially, are positioned two ferromagnetic discs (7a, 7b) made of soft iron, each extended radially by a plurality 2π / Ps of periodic teeth (42) spaced apart by a polar pitch Ps, with Ps expressed in radians and by the same number of notches (52). The teeth (42) extend radially in the direction of the first movable element (1). The discs (7a, 7b) as well as the magnet (6) are here secured to a shaft (8) which serves to position and guide the first (1) and second (2) elements, this shaft (8) extending along the axis of rotation (3).

[0037] The discs (7a, 7b) each have, and in this example, 18 teeth (42), each tooth of a disc (7a) being aligned radially with a tooth of the other disc (7b) symmetrically with respect to the transverse median plane of the magnet (6). The first movable element (1) has a set of 24 teeth (41), some of these teeth not being visible due to the partial section made on the first movable element (1). Due to the permanent magnet (6) whose magnetic flux passes through all the teeth (41, 42), the latter form magnetic poles attracting each other in order to maximize the overall magnetic flux passing in the air gap between the first movable element (1) and the second fixed element (2), between the teeth (41) and (42). This forms a set of stable and unstable positions and a periodic effort which can be felt by the user activating the first mobile element (1), in the form of successive notches.Due to the different number of teeth (41, 42) between the first movable element (1) and the second fixed element (2), the number of notches felt is then equal to the lowest common multiple (lcm) of the two numbers of magnetic poles at the first movable element (1) and at the second fixed element (2). In this example, the number of notches felt will thus be 72, lcm 18 and 24. The amplitude of the torque created and felt by the user can be adjusted by the axial dimension of the first (1) and second (2) elements as well as by the air gap between the first movable part (1) and the second fixed part (2). The shape of the teeth (41, 42) also makes it possible to play on this parameter as well as on the shape of the torque obtained over a period.

[0038] There figure 2 presents a variant embodiment of the figure 1 for which only the discs (7a, 7b) differ. Each of these discs has 8 teeth (42), the teeth (42) of each disc (7a, 7b) being angularly offset by half a period so that a tooth (42) of the disc (7a) is aligned with the middle of a notch (52) of the disc (7b) and vice versa. This variant makes it possible to minimize the number of teeth to be made on each of the discs while retaining the same number of notches felt by the user, here 72. The amplitude of the haptic sensation is however lower in this case compared to the first mode presented in figure 1 , due to the greater magnetic reluctance generated. In this embodiment, the discs (7a, 7b) are each radially extended by a plurality 2π / (2*Ps) of periodic teeth spaced apart by said polar pitch Ps multiplied by 2 and spaced between each disc by said pitch Ps expressed in radians.

[0039] There figure 3 presents a variant embodiment of the figure 1 for which the position of the magnet (6) is different, here installed in the first movable element (1), between two toothed discs (11a, 11b). The magnet (6) is in the form of an axially magnetized crown. The second fixed element (2) is in the form of a single toothed disc (7). In this example as in all the examples given here, the greatest number of teeth can be installed either on the first movable element (1) or on the second fixed element (2) without this departing from the present invention. Similarly, as in the other embodiments shown, a shaft (8) is not systematically necessary or shown. Finally, for rotary embodiments, the first movable element (1) can be installed outside or inside the second fixed element (2).

[0040] There figure 4 has a variant for which the magnetic interaction is achieved via a radial air gap between the first mobile element (1) and the second fixed element (2). The second fixed element (2) has a crown (12) extended axially by a set of teeth (42) made of soft ferromagnetic material radially facing a magnet crown (16) on the first mobile element (1). This first mobile element (1) is here in the form of a single piece, made of an injectable material which can be permanently magnetized, such as a plastic-bonded magnet. The magnet crown (16) is thus extended radially by a disc portion (13), itself extended axially by a magnetized plate (14). This plate (14) has here, in a non-limiting manner, two axially magnetized poles (N, S).These two magnetized poles (N, S) are not intended to cooperate magnetically with the teeth (42) of the second fixed element (2) but are intended for a function of detecting the position of the first mobile element when these magnetized poles (N, S) are opposite a Hall probe or a magneto resistive probe for example (not shown here).

[0041] This solution of the figure 4 is particularly interesting in order to produce an economical industrial solution, particularly when produced in a small size (typically with a total diameter of less than 20 mm). Indeed, in addition to the main interest proposed by the present invention, linked to the use of a different number of magnetic poles opposite each other in order to create a greater number of notches felt by the user, facilitating industrial production, the manufacture in a single piece of the first mobile element (1) and in a material which can be magnetized is particularly practical and economical, particularly with a view to implementing a position sensor. This position detection function will be particularly interesting when the haptic interface controls computer software or an electrified function in a vehicle.

[0042] There figure 5 has an axial embodiment variant, i.e. one in which the first movable element (1) faces axially the second fixed element (2). In this example and more particularly, the teeth (41) of the first movable element (1), in the form of a soft ferromagnetic material, extend radially and face axially the magnet ring (6) of the second fixed element (2). The first movable element (1) has 9 teeth (41) and the second fixed element (2) has a magnet (6) with 12 North and South poles so as to create 36 felt notches. The magnetization direction is here radial or preferably axial, which makes it possible to modify the amplitude of the felt torque. Still in this example, the first movable element (1) can become fixed and the second fixed element (2) can become movable, without this changing the general function described.Likewise, in this example and at the center of the device, a magnetized plate (14) is presented consisting of a north pole (N) and a south pole (S) used for detecting the relative position of the two elements (1 and 2) when this plate (14) is opposite a magnetosensitive probe (not shown here).

[0043] There figure 6 presents an alternative to the example presented in figure 4 for which the first movable element (1) has teeth (41) extending axially from a plate (11), the assembly being made of a soft ferromagnetic material. The second fixed element (2) has a magnetized ring (6) comprising an alternation of north and south poles oriented radially and facing, radially, the teeth (41). The rotation of the first movable element (1) is carried out around a shaft (8) fixed in a support (17) or sliding in this support (17).

[0044] There figure 7 is an alternative embodiment for which the first movable element (1) is in the form of a ferromagnetic ring (18) extended axially in a periodic manner by pairs of teeth (421, 422) forming an air gap in which the second fixed element (2) is placed in the form of a multipolar magnetized ring (6) magnetized, preferably, radially. In this example, the first movable element (1) can advantageously be produced in the form of a strip of material cut from a sheet of ferromagnetic material then folded locally in order to produce the pairs of teeth (421, 422).

[0045] There figure 8 has a variant where the first movable element (1) is in the form of a crown (31) periodically having recesses (32) to form periodically spaced teeth (41). In the representation, a part of the crown (31) is not shown to better appreciate the second fixed element (2) in the form of a magnet (6) whose magnetic orientation is axial along the axis (3), between two discs (11a, 11b) made of soft ferromagnetic material. These discs (11a, 11b) are extended axially by teeth (42, 42') - for example the teeth (42) are north poles and the teeth (42') south poles - so that the teeth (42, 42') are opposite each other and are all opposite, radially, the crown (31). All the teeth (41, 42, 42') form magnetic poles which work together to form a magnetic interaction and create a notch felt by the user who manipulates the crown (31).

[0046] There figure 9 illustrates an alternative embodiment showing that the invention, in rotating cases, is not limited to elements extending over 360°. The first movable element (1) has a cylindrical magnet (6) magnetized axially and placed between two discs (11a, 11b) extended radially by teeth (41, 41') forming an alternation of North and South magnetic poles. For example, the teeth (41) of the disc (11a) have a North polarity and the teeth (41') have a South polarity imposed by the magnet (6), the teeth (41, 41') being axially aligned. In this example, there are 18 teeth (41) and 18 teeth (41') in order to make 18 pairs of magnetic poles defining a polar pitch Pr. If one wishes to make 72 notches felt by the user, it is possible to use a second fixed element (2) with 24 teeth (42) made of soft ferromagnetic material, as explained above. However, it is not necessary to keep these 24 teeth to make 72 notches felt.Indeed, the magnitude of the torque felt is proportional to the greatest common divisor (GCD) which represents the number of patterns present in the interaction between the two elements (1, 2). In this example, to achieve 72 notches, the GCD is 6, which means that there is potentially a succession of 6 patterns generating the torque. It is then possible to use a single pattern for one of the elements, i.e. 24 / 6=4 teeth (42) on the second fixed element (2), or any multiple of 4 teeth (42). In this example, 1 pattern - and therefore 4 teeth (42) - is used over an angular extension of 60°. The magnitude of the torque felt is proportional to the number of patterns, which implies a lesser felt force in this example than in the case where a complete second fixed element (2) extending over 360° is used.

[0047] In figure 10 a variant of this embodiment is presented figure 9 which differs from the latter in that the permanent magnet (6a, 6b) used is bipolar, always axially magnetized - not visible in the figure - the magnet (6a) having a given axial polarity, the magnet (6b) having an opposite axial polarity. A slot (19) passes through the disc (11a) in order to create a magnetic cut-off and promote magnetic field leakage out of the disc (11a), the diametrical extent of the slot being parallel to the magnetic transition of the magnet (6a, 6b). The disc (11b) has 2*9 teeth (41') and the disc (11a) has 2*9 teeth (41). The total number of teeth (41, 41') per disc (11a, 11b) is still 18 but the leakage magnetic flux, axially facing the disc (11a) can be used for a position detection function when a magnetosensitive probe (not shown here) is placed opposite the disc (11a).

[0048] There figure 11 presents a linear variant of a device according to the invention. The first movable element (1) is in the form of a slider (20) - of the "fader" type for an audio mixing table - secured to a magnet (6) taken between two toothed elements (11c, 11d) each extended transversely by 3 teeth (41). These teeth (41) are opposite a target made of soft ferromagnetic material forming the second fixed element (2) extending linearly and comprising teeth (42) forming bars and above which the slider (20) moves along the axis (3), the first movable element (1) being separated from the second fixed element (2) by an air gap maintained by a guide not shown here.In this example, for a desired notch whose linear pitch is Pt, considering a rotary equivalent where there would be 72 notches felt over a complete revolution with a first mobile element (1) with 18 magnetic periods and a second fixed element (2) with 24 magnetic periods, the linear period of the teeth (41) of the first mobile element (1) must then be equal to Pr=72 / 18*Pt and the period of the ferromagnetic poles of the second fixed element (2) must then be equal to Ps=72 / 24*Pt. The GCD of 18 and 24 being 6, there is therefore a single 3-tooth pattern that can be used on the first mobile element (1). If, for example, one wishes to obtain a notch every 1 mm, the teeth (41) must have a periodicity of Pr=4 mm and the ferromagnetic poles of the second fixed element (2) a periodicity of Ps=3 mm. In this figure, the second fixed element (2) has a length of approximately 43 mm for a stroke of approximately 33 mm and as many notches felt by the user.

[0049] The figure 12 presents a spherical variant of a device according to the invention allowing a haptic feeling by the user when rotating a handle (21) actuating a ball joint (22), here along three orthogonal axes (3, 3' and 3"). In this example, which is not limiting in its shaping, the ball joint (22) has a plurality of poles made of soft ferromagnetic material which move, when the handle (21) is actuated, in front of three pairs of fixed elements (2), formed of a stack of sheets of soft ferromagnetic material (22a, 22b), (22c, 22d) and (22e, 22f) on either side of discrete permanent magnets (6), preferably oriented perpendicular to said sheets (22a, 22b), (22c, 22d) and (22e, 22f) which are extended radially by teeth (42) opposite the ball joint (22) in order to interact magnetically with said ball joint (22), the latter being separated from the fixed elements (2) by a small radial air gap.The guidance of the ball joint (22) is achieved by an additional element not shown here. The dimensioning of this variant will be done on the basis of the lessons learned from the variant of the . figure 11 .

[0050] THE figures 13a et 13b are two different perspective views of the same example of realization, with the figure 13 presenting a partial cut, quite similar to that of the figure 4 , which differs from the latter by the number of magnetized poles and the number of ferromagnetic poles. In this example, the first mobile element (1) has a magnetized crown (16) with 8 radially oriented North-South polarities and the second fixed element (2) has a crown (12) made of ferromagnetic material extended axially by 6 teeth (42), the first (1) and second (2) elements facing each other radially. This configuration makes it possible to generate a force with 24 periods per revolution. A hub (23) is integral with the crown (12) in order to allow the guidance and rotation of the first mobile element (1) relative to the second fixed element (2). In the same way as in the previous examples, the mobile element can become fixed and the fixed element can become mobile, the relative movement being the same.

[0051] THE figures 14a et 14b are in all respects similar to the figures 13a et 13b , except that the second fixed element (2) has only 3 teeth (42) extending the ferromagnetic crown (12). The number of notches obtained is thus the same, i.e. 24, but according to a less significant amplitude of the force obtained, due to the lower number of magnetic interactions, by a stronger overall magnetic reluctance.

[0052] There figure 15 shows an example of an implementation similar to that of the figure 4 for which the first (1) and the second (2) elements each have 24 poles in order to produce 24 notches.

[0053] There figure 16 shows a final example of embodiment in which the first mobile element (1) and the second fixed element (2) comprise a permanent magnet, respectively (6a) and (6b). In this non-limiting example, there are 20 polarities for the magnet (6a), preferably oriented radially, and 12 polarities for the magnet (6b), in order to produce 60 notches.

Claims

1. Passive haptic interface comprising a first element (1) rotatably or translatably movable with respect to a second element (2), said first movable element (1) rotating or moving in relation to said second element (2), the first movable element (1) having a first plurality of magnetic poles periodically spaced according to a pole pitch Ps and according to the direction of movement, said second fixed element (2) having a second plurality of magnetic poles periodically spaced according to a pole pitch Pr and according to the direction of movement, wherein Ps and Pr are different numbers from one another, a periodic stress being created by the magnetic interaction between said first movable element (1) and second fixed element (2) according to a period Pt, said first movable element (1) rotates about an axis (3) or moves in translation along an axis (3), said first movable element (1) rotating or moving in relation to a second fixed element (2), said first movable element (1) having a first plurality of magnetic poles periodically spaced according to a pole pitch Ps and according to the direction of movement, said second fixed element (2) having a second plurality of magnetic poles periodically spaced according to a pole pitch Pr and according to the direction of movement, wherein Ps and Pr are different numbers from one another, a periodic stress being created by the magnetic interaction between said first movable element (1) and second fixed element (2) according to a period Pt, characterized in that Ps and Pr are chosen such that Pt is strictly less than the smallest of the Ps and Pr pitches.

2. Passive rotary haptic interface according to claim 1, characterized in that the number of periods of said periodic stress is equal to the least common multiple of the numbers of periods of magnetic poles at said first movable element (1) and at said second fixed element (2).

3. Passive rotary haptic interface according to claim 2, characterized in that one of said first movable element (1) or said second fixed element (2) comprises a cylindrical permanent magnet (6) having an alternation of North and South poles forming said first plurality of magnetic poles, in that the other of said first movable element (1) or said second fixed element (2) has a plurality of teeth (41, 42) connected by a ring (12) and forming said second plurality of magnetic poles, said teeth (41, 42) and ring (12) being made of a soft ferromagnetic material, said period Pt of magnetic interaction being at least two times less than the smallest of the pitches Ps and Pr.

4. Passive rotary haptic interface according to claim 1, characterized in that said first movable element (1) and said second fixed element (2) comprise a permanent magnet (6) having an alternation of North and South poles forming said pole pitches Ps and Pr.

5. Rotary passive haptic interface according to claim 1, characterized in that the second fixed element (2) comprises a magnet (6) having a unidirectional magnetization oriented along said axis (3) and in that it comprises, axially on either side, two ferromagnetic discs (7a, 7b) made of soft iron extended radially and each by a plurality 2π / Ps of teeth (42) periodically spaced by said pole pitch Ps expressed in radians.

6. Rotary passive haptic interface according to claim 1, characterized in that the second fixed element (2) comprises a magnet (6) having a unidirectional magnetization oriented along said axis (3) and in that it comprises, axially on either side, two ferromagnetic discs (7a, 7b) made of soft iron extended radially and each by a plurality 2π / (2*Ps) of teeth periodically spaced by said pole pitch Ps multiplied by 2 and spaced between each disc by said pitch Ps expressed in radians.

7. Rotary passive haptic interface according to claim 1, characterized in that the first movable element (1) comprises two discs (11a, 11b) axially on either side of a unipolar permanent magnet (6) and in that the second fixed element (2) comprises a disc (7) made of a soft ferromagnetic material, said discs (11a, 11b and 7) each being extended radially by teeth, respectively (41, 42), radially facing and spaced by said pitch Ps.

8. Linear passive haptic interface according to claim 1, characterized in that said first movable element (1) comprises a permanent magnet magnetized transversely to the movement of said first movable element (1) along said axis (3) and positioned transversely between two toothed elements (11c) made of a soft ferromagnetic material having teeth (41) and in that the second fixed element (2) is made of a ferromagnetic material comprising teeth (42) forming bars and extending linearly, said first fixed element (1) moving linearly above the second fixed element (2).

9. Spherical passive haptic interface according to claim 1, characterized in that said first movable element (1) comprises a ball joint (22) capable of rotating about three orthogonal axes (3, 3', 3"), in that said ball joint (22) comprises a set of teeth (41) extending radially, in that the second fixed element (2) is formed by a plurality of fixed elements (2) in the form of a stack of metal sheets (22a to 22f) of soft ferromagnetic material on either side of discrete permanent magnets (6) oriented perpendicularly to said metal sheets (22a to 22f), said metal sheets (22a to 22f) being extended radially by teeth (42) in relation to said ball joint (22).

10. Rotary passive haptic interface according to claim 1, characterized in that a first movable element (1) comprises a ring of permanent magnets (6) extending axially and secured to a disc part (13), said disc part (13) being extended axially in a direction opposite said magnets (6) by a magnetic plate (14) used for the position detection of said first movable element (1), and in that a second fixed element (2) comprises a ring (12) made of a soft ferromagnetic material extended by teeth (41) facing said ring of permanent magnets (6).

11. Rotary passive haptic interface according to the preceding claim, characterized in that said ring of magnets (6), said disc part (13) and said magnetic plate (14) are made from a single injected plastics bonded material that can be permanently magnetized.

12. Rotary passive haptic interface according to claim 10, characterized in that said disc part (13) is made from an injected plastics bonded material on which said magnetic plate (14) is securely attached.

13. Rotary passive haptic interface according to claim 12, characterized in that said plate (14) is made from a plastics bonded material injected onto said disc part (13).