DEVICE FOR CONTROLLING MOTION SICKNESS, WHICH IS INTEGRATED INTO A MOTOR VEHICLE

20230013174 · 2023-01-19

    Inventors

    Cpc classification

    International classification

    Abstract

    An anti-motion sickness device for a motor vehicle includes a triaxial accelerometer to detect vehicle accelerations along three axes and to emit a corresponding acceleration signal; a display component of light markers to form two artificial horizon lines at two inner surfaces, respectively of the vehicle. The horizon lines are perpendicular or substantially perpendicular to each other. The device includes a control unit for receiving the acceleration signals emitted by the accelerometer and capable of driving the display component such that the horizon lines are aligned in a horizontal plane, perpendicular or substantially perpendicular to the gravity vector regardless of vehicle accelerations. The position of the horizontal plane along a direction parallel to the gravity vector varies as a function of a physical parameter related to the person sitting in the vehicle by being positioned adjacent the first inner surface and in front of the second inner surface.

    Claims

    1. An anti-kinetosis device fitted to a motor vehicle, wherein the anti-kinetosis device comprises: a triaxial accelerometer configured to detect the accelerations of the vehicle along three axes and to emit a corresponding acceleration signal; means for displaying light markers capable of forming at least one first artificial horizon line at the level of a first internal surface of the motor vehicle and at least one second artificial horizon line at the level of a second internal surface of the motor vehicle, said first and second artificial horizon lines being perpendicular or substantially perpendicular to each other; a control unit able to receive the acceleration signals emitted by the accelerometer and to drive said display means so that the first and second artificial horizon lines are aligned in a horizontal plane, perpendicular or substantially perpendicular plane to the gravitational vector, whatever the accelerations of the vehicle, the position of said horizontal plane along a direction parallel to the gravitation vector which can vary according to a physical parameter linked to the person seated in the motor vehicle by being positioned just beside the first internal surface and just in front of the second internal surface.

    2. The device according to claim 1, wherein the physical parameter is the height of the person, in a seated position in the vehicle.

    3. The device according to claim 1, wherein the control unit is capable of modifying the position of the horizontal plane defined by the first and second artificial horizon lines in response to a command entered manually by one of the occupants of the vehicle by means of a command interface.

    4. The device according to claim 3, wherein the command interface is integrated into the dashboard of the vehicle.

    5. The device according to claim 3, wherein the command interface is integrated in a central upright of the vehicle.

    6. The device according to claim 4, wherein the command interface comprises an external surface functionally linked to detection means of the capacitive type, said detection means being capable of detecting the contact of a finger on said external surface and transmitting a corresponding signal to the control unit.

    7. The device according to claim 1, wherein the control unit is adapted to automatically modify the position of the horizontal plane defined by the first and second artificial horizon lines in response to a signal emitted by a sensor configured to detect at least one physical parameter, in particular the position of the eyes, of the person seated just beside the first internal surface and just in front of the second internal surface.

    8. The device according to claim 7, wherein the sensor is selected among a camera, an ultrasound sensor, a radio frequency sensor and a weight measurement sensor positioned in one of the vehicle seats.

    9. The device according to claim 1, wherein the display means are able to emit at least two light beams of a rectilinear shape, respectively a first light beam projected on the first internal surface and forming the first artificial horizon line, and a second light beam projected onto the second internal surface and forming the second artificial horizon line.

    10. The device according to claim 9, wherein the display means comprise at least one light source emitting a main light beam, and means for separating and deflecting said main light beam into two secondary light beams.

    11. The device according to claim 10, wherein the separation and deflection means comprise a prism intended to separate the light beam into two secondary light beams and a combination of mirrors and/or lenses intended to modify the path of said secondary light beams.

    12. The device according to claim 9, wherein the display means comprise at least one pair of light sources, respectively a first light source emitting the first light beam and a second light source emitting the second light beam.

    13. The device according to claim 10, wherein the light source, respectively the pair of light sources, is a laser, respectively a pair of lasers.

    14. The device according to claim 1, wherein the display means comprise at least three light columns oriented vertically, respectively a first light column arranged in alignment with the first internal surface and in alignment with the second internal surface, a second light column disposed in alignment with the second internal surface and to the left or to the right of the first light column, and a third light column disposed in alignment with the first internal surface and closer to the rear of the vehicle than the first light column, each of the light columns being formed of a plurality of vertically aligned light points, each of the light points being able to emit light in an activated state and not emit light in a deactivated state, and in that the first artificial horizon line is formed by the virtual line passing through the highest or lowest activated light points on the first and third light columns respectively and the second artificial horizon line is formed by the virtual line passing through the highest or lowest activated light points on the first and second light columns respectively.

    15. The device according to claim 14, wherein each of the light columns comprises a linear network of vertically lined light-emitting diodes, each of the light-emitting diodes forming a light point.

    16. A motor vehicle equipped with an anti-kinetosis device according to claim 1.

    17. The motor vehicle equipped with an anti-kinetosis device according to claim 9, the motor vehicle comprises at least one central upright, said central upright supporting the display means, said display means being configured to project the first light beam onto a rear lateral window or a rear door panel of the vehicle and to project the second light beam onto an internal surface of the passenger compartment arranged substantially perpendicular to said window or to said door panel, for example the backrest of one of the front seats of the vehicle.

    18. The vehicle according to claim 17, wherein the display means are displaceable along the central upright configured to allow adjustment of the height of the artificial horizon lines with respect to a fixed horizontal plane.

    19. A method for displaying light markers intended to combat motion sickness, the method including the following steps: detecting the accelerations of a motor vehicle along 3 axes and sending corresponding signals to a control units, detecting a physical parameter related to the person seated in the motor vehicle and sending a corresponding signal to the control unit, and driving by the control unit of means for displaying light markers capable of forming at least one first artificial horizon line at the level of a first internal surface of the motor vehicle and at least one second artificial horizon line at the level of a second internal surface of the motor vehicle, said first and second artificial horizon lines being perpendicular or substantially perpendicular to each other, such that the first and second artificial horizon lines are aligned in a horizontal plane, perpendicular to the gravitation vector, whatever the accelerations of the vehicle, the position of said horizontal plane along a direction parallel to the gravitation vector being able to vary according to the detected physical parameter.

    Description

    BRIEF DESCRIPTION OF THE DRAWINGS

    [0034] Other features and advantages will become apparent from the description below of two particular embodiments of the disclosure, given by way of non-limiting examples, with reference to the appended drawings in which:

    [0035] FIG. 1 is a perspective view from the rear of the passenger compartment of a vehicle according to a first embodiment of the disclosure and according to a first operating mode of the anti-kinetosis device, the vehicle not being subjected to any acceleration;

    [0036] FIG. 1a is a rear view of the vehicle shown in FIG. 1;

    [0037] FIG. 1b is a lateral view of the vehicle shown in FIG. 1;

    [0038] FIG. 2 is a view similar to FIG. 1, in a second operating mode of the anti-kinetosis device;

    [0039] FIG. 2a is a view similar to FIG. 2, in which a first example of a command interface is shown;

    [0040] FIG. 2b is a view similar to FIG. 2, in which a second example of a command interface is shown;

    [0041] FIG. 2c is a perspective view from the front of the passenger compartment of the vehicle shown in FIG. 1, in which an example of a sensor is shown;

    [0042] FIG. 3 is a view similar to FIG. 1, the vehicle being subjected to an acceleration along the Y axis;

    [0043] FIG. 3a is a rear view of the vehicle shown in FIG. 3;

    [0044] FIG. 3b is a lateral view of the vehicle shown in FIG. 3;

    [0045] FIG. 4 is a view similar to FIG. 1, the vehicle being subjected to an acceleration along the X axis;

    [0046] FIG. 4a is a rear view of the vehicle shown in FIG. 4;

    [0047] FIG. 4b is a lateral view of the vehicle shown in FIG. 4;

    [0048] FIG. 5 is a view similar to FIG. 1, the vehicle being subjected to an acceleration along the X axis and along the Y axis;

    [0049] FIG. 5a is a rear view of the vehicle shown in FIG. 5;

    [0050] FIG. 5b is a lateral view of the vehicle shown in FIG. 5;

    [0051] FIG. 6 is a view similar to FIG. 1, the vehicle being subjected to an acceleration along the Y axis;

    [0052] FIG. 6a is a rear view of the vehicle shown in FIG. 6;

    [0053] FIG. 6b is a lateral view of the vehicle shown in FIG. 6;

    [0054] FIG. 7 is a perspective view of the passenger compartment of a vehicle according to a second embodiment of the disclosure, the vehicle not being subjected to any acceleration;

    [0055] FIG. 7a is a rear view of the vehicle shown in FIG. 7;

    [0056] FIG. 7b is a lateral view of the vehicle shown in FIG. 7;

    [0057] FIG. 8 is a view similar to FIG. 7, the vehicle being subjected to an acceleration along the Y axis;

    [0058] FIG. 8a is a rear view of the vehicle shown in FIG. 8;

    [0059] FIG. 8b is a lateral view of the vehicle shown in FIG. 8;

    [0060] FIG. 9 is a view similar to FIG. 7, the vehicle being subjected to an acceleration along the X axis;

    [0061] FIG. 9a is a rear view of the vehicle shown in FIG. 9;

    [0062] FIG. 9b is a lateral view of the vehicle shown in FIG. 9;

    [0063] FIG. 10 is a view similar to FIG. 7, the vehicle being subjected to an acceleration along the X axis and along the Y axis;

    [0064] FIG. 10a is a rear view of the vehicle shown in FIG. 10;

    [0065] FIG. 10b is a lateral view of the vehicle shown in FIG. 10;

    [0066] FIG. 11 is a view similar to FIG. 7, the vehicle being subjected to an acceleration along the Y axis;

    [0067] FIG. 11a is a rear view of the vehicle shown in FIG. 11; and

    [0068] FIG. 11b is a lateral view of the vehicle shown in FIG. 11.

    DETAILED DESCRIPTION OF THE DRAWINGS

    [0069] In the remainder of this description, and with reference to the Cartesian coordinate system XYZ shown in FIGS. 1 and 7, the terms «longitudinal direction» will be used for a direction along the X axis, «transverse direction» for a direction along the Y axis and «vertical direction» for a direction along the Z axis. Moreover, conventionally, the term «front» will be used to indicate an orientation directed towards the front of the vehicle and the term «rear» will be used to indicate an orientation directed towards the rear of the vehicle.

    [0070] With reference to FIG. 1, there is shown a passenger compartment of a vehicle 10 according to a first embodiment of the disclosure. In this embodiment, a first lighting column 12 oriented vertically is supported by a central upright 11 of the vehicle and is arranged on the left side with respect to the field of view of a passenger sitting at the rear of the vehicle, and a second lighting column 12′ oriented vertically is supported by another central upright 11′ of the vehicle and is arranged on the right side with respect to the field of view of a passenger sitting in the back of the vehicle. Each lighting column 12, 12′ comprises at least one light source configured to project a first rectilinear light beam onto a rear lateral window or a rear door panel 13 of the vehicle and to project a second rectilinear light beam onto the backrest of one of the front seats 15 or 15′ of the vehicle. The first light beam emitted by the first lighting column 12 projects onto the rear lateral window or the rear door panel 13 directly adjacent to the first lighting column 12 along a first line 14, subsequently referenced as the first artificial horizon line, and the second light beam emitted by the first lighting column 12 projects onto the backrest of the front seat 15 directly adjacent to the first lighting column 12 along a second line 16, subsequently referenced as the second artificial horizon line. Similarly, the first light beam emitted by the second lighting column 12′ projects onto the rear lateral window or the rear door panel (not shown) directly adjacent to the second lighting column 12′ along a first line 14′, subsequently referred to as the first artificial horizon line, and the second light beam emitted by the second lighting column 12′ projects onto the backrest of the front seat 15′ directly adjacent to the second lighting column 12′ along a second line 16′, subsequently referenced as the second artificial horizon line. In this configuration, the first and second artificial horizon lines are perpendicular or substantially perpendicular to each other.

    [0071] By suitably driving the light source(s), it is thus possible to align the first and second artificial horizon lines 14, 16 and 14′, 16′ in a horizontal plane A which is always perpendicular to the gravitation vector. Thus, a person seated next to the rear lateral window 13 and behind the front seat 15 and fixing said artificial horizon lines 14, 16 will have the same visual sensations as the driver looking at the road: he will therefore no longer be subject to motion sickness. To achieve this result, the vehicle 10 is advantageously equipped with a triaxial accelerometer configured to detect the accelerations of the vehicle along the 3 axes X, Y and Z and emit corresponding acceleration signals, and a control unit able to receive the acceleration signals emitted by the accelerometer and to drive the light source(s) so that the first and second artificial horizon lines 14, 16 and 14′, 16′ are aligned in a horizontal plane A, perpendicular to the gravitation vector, whatever the accelerations of the vehicle.

    [0072] FIGS. 1, 1a, 1b, 3 to 6, 3a to 6a and 3b to 6b illustrate several possible driving conditions and the corresponding operation of the anti-kinetosis device fitted to the vehicle of the disclosure.

    [0073] Thus, in the case where the vehicle 10 travels on a flat road, as shown in FIGS. 1a and 1b, it is not subject in principle to any acceleration. In this case, the plane A defined by the artificial horizon lines 14, 16 and 14′, 16′ is parallel to the floor pan P of the vehicle.

    [0074] In the case where the vehicle 10 is traveling on a road inclined to the left with respect to a fixed horizontal plane H, perpendicular to the gravitation vector, as represented in FIGS. 3a and 3b, it is subjected to an acceleration along the Y axis. This acceleration is detected by the triaxial accelerometer, which sends a corresponding acceleration signal to the control unit. In response to this acceleration signal, the control unit controls the corresponding light sources of the first and second lighting columns 12, 12′ so as to align the light beams emitted by said light sources with the fixed horizontal plane H. In this case, the plane A defined by the artificial horizon lines 14, 16 and 14′, 16′ is inclined with respect to the floor pan P of the vehicle at the level of the Y axis, as shown in FIG. 3.

    [0075] In the case where the vehicle 10 is traveling on a road inclined downwards with respect to a fixed horizontal plane H, perpendicular to the gravitation vector, as shown in FIGS. 4a and 4b, it is subjected to an acceleration along the X axis. This acceleration is detected by the triaxial accelerometer, which sends an acceleration signal corresponding to the control unit. In response to this acceleration signal, the control unit controls the corresponding light sources of the first and second lighting columns 12, 12′ so as to align the light beams emitted by said light sources with the fixed horizontal plane H. In this case, the plane A defined by the artificial horizon lines 14, 16 and 14′, 16′ is inclined with respect to the floor pan P of the vehicle at the level of the X axis, as shown in FIG. 4.

    [0076] In the case where the vehicle 10 is traveling on a road inclined to the left and downwards with respect to a fixed horizontal plane H, perpendicular to the gravitation vector, as represented in FIGS. 5a and 5b, it is subjected to an acceleration according to the X axis and along the Y axis. This acceleration is detected by the triaxial accelerometer, which sends a corresponding acceleration signal to the control unit. In response to this acceleration signal, the control unit controls the corresponding light sources of the first and second lighting columns 12, 12′ so as to align the light beams emitted by said light sources with the fixed horizontal plane H. In this case, the plane A defined by the artificial horizon lines 14, 16 and 14′, 16′ is inclined with respect to the floor pan P of the vehicle at the level of the axes X and Y, as shown in FIG. 5.

    [0077] In the case where the vehicle 10 is traveling on a flat road and makes a left turn, as represented in FIGS. 6a and 6b, it is subjected to an acceleration along the Y axis. This acceleration is detected by the triaxial accelerometer, which sends a corresponding acceleration signal to the control unit. In response to this acceleration signal, the control unit controls the corresponding light sources of the first and second lighting columns 12, 12′ so as to align the light beams emitted by said light sources with the fixed horizontal plane H. In this case, the plane A defined by the artificial horizon lines 14, 16 and 14′, 16′ is inclined with respect to the floor pan P of the vehicle at the level of the Y axis, as shown in FIG. 6.

    [0078] The light beams from each of the lighting columns 12, 12′ may be generated by two separate light sources, or by a single light source emitting a main light beam, said main light beam being subsequently separated and deflected into two secondary light beams by separation and deflection means. Said separation and deflection means may for example consist of a prism intended to separate the light beam into two secondary light beams and of a combination of mirrors and/or lenses intended to modify the path of said secondary light beams.

    [0079] The light source(s) can advantageously be displaced along each of the lighting columns 12, 12′ so as to modify the height of the artificial horizon lines 14, 16 and 14′, 16′ with respect to a fixed horizontal plane. Thus, and as shown in FIG. 2, the position of the light source(s) along the first lighting column 12 could for example be higher than the position of the light source(s) along the second lighting column 12′. This configuration is particularly suitable if the person seated in the left rear seat 17 is taller than the person seated in the right rear seat 17′. This modification of the position of the light source(s) along the lighting column 12, 12′ can be done using displacement means controlled by the control unit and in response to a command entered manually by one of the occupants of the vehicle by means of a command interface 19, which can be integrated for example in the dashboard 18, as illustrated in FIG. 2a, or in the central upright(s) 11, 11′ of the vehicle, as illustrated in FIG. 2b. A command interface usable at this level may comprise an external surface functionally linked to detection means of the capacitive type, said detection means being able to detect the contact of a finger on said external surface and to transmit a corresponding signal to the control unit. In another possible configuration, the displacement of the light source(s) along one of the lighting columns 12, 12′ could be carried out automatically in response to a signal emitted by a sensor configured to detect at least one physical parameter, in particular the size or position of the eyes, of the person seated closest to the lighting column. The sensor could for example be a camera 21, as shown in FIG. 2c, an ultrasonic sensor, a radiofrequency sensor or a weight measuring sensor integrated in one of the vehicle seats.

    [0080] With reference to FIG. 7, there is shown a passenger compartment of a vehicle according to a second embodiment of the disclosure. In this embodiment, the anti-kinetosis device comprises at least three light columns oriented vertically, respectively a first light column 12 which is supported by a central upright 11 of the vehicle and which is arranged on the left side with respect to the field of view of a passenger seated at the rear of the vehicle, a second light column 12′ which is supported by another central upright 11′ of the vehicle and which is arranged on the right side with respect to the field of view of a passenger seated at the rear of the vehicle, and a third light column 12″ which is supported by a lateral upright 11″ forming part of a rear lateral window or a rear door panel 13 and on the left side with respect to the field of view of a passenger seated in the rear of the vehicle. Each light column 12, 12′, 12″ is formed by a plurality of light points aligned in the vertical direction, each of the light points being able to emit light in an activated state and not emit light in a deactivated state. Thus, a first artificial horizon line 14 is formed by the virtual straight line passing through the highest activated light points 17 and 17″ on the first and third light columns 12, 12″ respectively, and a second artificial horizon line 16 is formed by the virtual line passing through the highest activated light points 17 and 17′ on the first and second light columns 12, 12′ respectively. In this configuration, the first and second artificial horizon lines 14, 16 are perpendicular or substantially perpendicular to each other. In an advantageous variant of the disclosure, each of the light columns 12, 12′ and 12″ may comprise, for example, a linear network of vertically lined light-emitting diodes, each of the light-emitting diodes forming one of the light points of the light columns. In another configuration of the disclosure, the light points can be activated starting from the top of each light column. In this case, the first artificial horizon line 14 will be formed by the virtual straight line passing through the lowest activated light points on the first and third light columns 12, 12″ respectively, and the second artificial horizon line 16 will be formed by the virtual straight line passing through the lowest activated light points on the first and second light columns 12, 12′ respectively. Moreover, the vehicle 10 may advantageously comprise a fourth light column (not shown) which will be supported by a lateral upright forming part of a rear lateral window or of a rear door panel and on the right side with respect to the field of view of a passenger seated at the rear of the vehicle, said fourth light column making it possible to define, in combination with the second light column 12′, a third artificial horizon line 14′ on the right side of the vehicle.

    [0081] By appropriately driving the light-emitting diodes of the first, second and third light columns 12, 12′ and 12″, it is thus possible to align the first and second artificial horizon lines 14, 16 in a horizontal plane A which is always perpendicular to the gravitation vector. Thus, a person seated next to a rear lateral window or a rear lateral door panel 13 and behind the front seat 15 and fixing said artificial horizon lines 14, 16 will have the same visual sensations as the driver looking at the road: he will therefore not be no longer subject to motion sickness. As in the embodiment of FIG. 1, the drive of the light-emitting diodes is carried out by means of a triaxial accelerometer and a control unit able to receive the acceleration signals emitted by the accelerometer. The control unit can also control the height of the highest or lowest points of light, depending on a physical parameter linked to the person sitting in one of the rear seats. In particular, a sensor arranged inside the passenger compartment may be configured to detect at least one physical parameter, in particular the size or the position of the eyes, of the person seated on one of the rear seats and to transmit the information corresponding to the control unit. In response to the information transmitted by the sensor, the control unit is capable of modifying the height of the highest or lowest light point of each of the light columns so as to align it, for example with the position of the eyes of the person sitting in the back, which was previously detected by the sensor.

    [0082] FIGS. 7 to 11, 7a to 11a and 7b to 11b illustrate several conditions of possible conduct and the corresponding operation of the anti-kinetosis device of the disclosure fitted to the vehicle.

    [0083] Thus, in the case where the vehicle 10 is traveling on a flat road, as represented in FIGS. 7a and 7b, it is in principle not subjected to any acceleration. In this case, the plane A defined by the artificial horizon lines 14, 16 is parallel to the floor pan P of the vehicle.

    [0084] In the case where the vehicle 10 is traveling on a road inclined to the left with respect to a fixed horizontal plane H, perpendicular to the gravitation vector, as represented in FIGS. 8a and 8b, it is subjected to an acceleration along the Y axis. This acceleration is detected by the triaxial accelerometer, which sends a signal acceleration corresponding to the control unit. In response to this acceleration signal, the control unit controls the light-emitting diodes of the first, second and third light columns 12, 12′, 12″ so as to align the first and second artificial horizon lines 14, 16 with the fixed horizontal plane H. In this case, the plane A defined by the artificial horizon lines is inclined with respect to the floor pan P of the vehicle at the level of the Y axis, as shown in FIG. 8.

    [0085] In the case where the vehicle 10 is traveling on a road inclined downwards with respect to a fixed horizontal plane H, perpendicular to the gravitation vector, as represented in FIGS. 9a and 9b, it is subjected to an acceleration along the X axis. This acceleration is detected by the triaxial accelerometer, which sends a corresponding acceleration signal to the control unit. In response to this acceleration signal, the control unit controls the corresponding light-emitting diodes of the first, second and third light columns 12, 12′, 12″ so as to align the first and second artificial horizon lines 14, 16 with the fixed horizontal plane H. In this case, the plane A defined by the artificial horizon lines is inclined with respect to the floor pan P of the vehicle at the level of the X axis, as shown in FIG. 9.

    [0086] In the case where the vehicle 10 is traveling on a road inclined to the left and downwards with respect to a fixed horizontal plane H, perpendicular to the gravitation vector, as represented in FIGS. 10a and 10b, it is subjected to an acceleration according to the X axis and along the Y axis. This acceleration is detected by the triaxial accelerometer, which sends a corresponding acceleration signal to the control unit. In response to this acceleration signal, the control unit controls the corresponding light-emitting diodes of the first, second and third light columns 12, 12′, 12″ so as to align the first and second artificial horizon lines 14, 16 with the fixed horizontal plane H. In this case, the plane A defined by the artificial horizon lines is inclined with respect to the floor pan P of the vehicle at the level of the axes X and Y, as shown in FIG. 10.

    [0087] In the case where the vehicle 10 is traveling on a flat road and makes a left turn, as shown in FIGS. 11a and 11b, it is subjected to an acceleration along the Y axis. This acceleration is detected by the triaxial accelerometer, which sends a corresponding acceleration signal to the control unit. In response to this acceleration signal, the control unit controls the corresponding light-emitting diodes of the first, second and third light columns 12, 12′, 12″ so as to align the first and second artificial horizon lines 14, 16 with the fixed horizontal plane H. In this case, the plane A defined by the artificial horizon lines is inclined with respect to the floor pan P of the vehicle at the level of the Y axis, as shown in FIG. 11.

    [0088] The two embodiments described above are obviously not limiting for the disclosure. Other embodiments could be envisaged at this level.

    [0089] Moreover, the disclosure also aims to protect a method for displaying light markers intended to combat the kinetosis. This method may in particular comprise the following steps of: [0090] detecting the accelerations of a motor vehicle along 3 axes, in particular by means of a triaxial accelerometer, and sending corresponding signals to a control unit; [0091] detecting a physical parameter related to the person seated in the motor vehicle and sending a corresponding signal to the control unit; [0092] driving by the control unit of means for displaying light markers capable of forming at least one first artificial horizon line at the level of a first internal surface of the motor vehicle and at least one second artificial horizon line at the level of a second internal surface of the motor vehicle, said first and second artificial horizon lines being perpendicular or substantially perpendicular to each other, such that the first and second artificial horizon lines are aligned in a horizontal plane, perpendicular to the gravitation vector, whatever the accelerations of the vehicle, the position of said horizontal plane along a direction parallel to the gravitation vector being able to vary according to the detected physical parameter.