GUIDANCE SYSTEM FOR ELECTRIC VEHICLE CHARGING SYSTEM

Abstract

The invention relates to a guidance system for managing a positioning of an electric vehicle above a ground-based charging base, within a prescribed tolerance, the positioning being obtained by maneuvers of a driver of the electric vehicle, the system comprising one or more magnetic field emitting element(s) (2), positioned in a stationary manner in the charging base or in a manner connected to the charging base, adapted to generate a magnetic field (B) of constant direction and intensity, the system comprising at least three magneto-sensitive elements (3) arranged in the underbody area of ​​the vehicle, adapted to receive the magnetic field emitted by the magnetic field emitting element, the system comprising at least one processing unit (4), the magneto-sensitive elements together providing signals which are transformed by the processing unit into maneuvering instruction(s) intended for the driver. Figure 2

Description

Title of the invention: GUIDANCE SYSTEM FOR ELECTRIC VEHICLE CHARGING SYSTEM

[0001] The present invention relates to a guidance system for a so-called "comfort" electric vehicle charging system ('comfort charging' in the jargon of the trade).

[0002] Such a comfort charging system comprises a ground-mounted charging base and a connector on board the vehicle, the two entities being configured to be coupled conductively or inductively so that electrical charging of the vehicle can occur.

[0003] Under these conditions, the driver of the vehicle does not need to manipulate any socket or plug or cable to connect the vehicle to a charging station, so that the system of the connector on board the vehicle and the ground charging base can cooperate correctly.

[0004] However, the driver of the vehicle must bring the vehicle into a suitable position. This is the only positive action that the driver must take, with the possible addition of triggering the actual charging.

[0005] In the context of the present invention, the coupling may be conductive or the coupling may be electromagnetic (coil-to-coil transmission without direct electrical contact).

[0006] It is noted that there are two distinct systems regardless of the physical coupling mode: either the ground-based charging base comprises a telescopic arm which approaches or even contacts the connector on board the vehicle, or the connector on board the vehicle descends to come towards the ground-based charging base.

[0007] In both cases, telescopic kinematics makes it possible to compensate for imprecise and / or imperfect positioning of the vehicle, provided that this positioning remains within the prescribed tolerance. It is also noted that the telescopic kinematics and / or the connection method makes it possible to compensate for any angular deviation from the vertical axis, i.e. a vehicle slightly at an angle relative to a position aligned with the nominal longitudinal direction of the location. The ground-based charging base can be installed indoors or outdoors, on a parking space or not. The local ground may or may not be horizontal (inclined location), within a limit dependent on the technology used.

[0008] Depending on the different systems developed and / or offered on the market, the tolerance interval prescribed for the telescopic kinematics to function and compensate for the inaccuracy of the positioning, can be more or less wide; in practice it can be a few tens of centimeters.

[0009] Even if the tolerance interval is quite large, it turns out in practice that some drivers are not comfortable positioning their vehicle in the right place, particularly in the longitudinal direction.

[0010] In order to overcome this drawback, some have already proposed complex systems based on inductive coils producing complex signals which must be received and decoded, but this type of system proves to be expensive and difficult to implement.

[0011] Thus there remains a need to propose new solutions to provide positioning guidance for comfort recharging, which is economical and efficient.

[0012] For this purpose, the present invention proposes a guidance system for managing a positioning of an electric vehicle above a ground-based charging base, within a prescribed tolerance, the positioning being obtained by one or more maneuvers of a driver of the electric vehicle, the system comprising at least one magnetic field emitting element, positioned stationarily in the charging base or in a manner connected to the charging base, adapted to generate a magnetic field of constant direction and intensity, the system comprising at least three magneto-sensitive elements mounted on the vehicle, arranged in an underbody area of ​​the vehicle, adapted to receive the magnetic field emitted by the magnetic field emitting element, the ground having a ground plane and a ground normal, the emitted magnetic field having a north-south magnet axis aligned with the ground normal and a distribution of revolution around the magnet axis,the system comprising at least one processing unit, characterized in that the magneto-sensitive elements together provide signals which are transformed by the processing unit into maneuvering instructions intended for the driver.

[0013] Advantageously, this system is particularly simple, economical, and efficient. It has a rustic operation, it does not generate electromagnetic disturbances and is insensitive to disturbed electromagnetic environments.

[0014] The proposed system is compatible with any 'comfort recharge' type charging system, depending on the electrical or magnetic connection and depending on the vehicle or ground part which has a telescopic element.

[0015] Thanks to the maneuvering instructions, the driver can adjust the current position of his vehicle and can thus complete the maneuver with the assurance that the cooperation between the ground-based charging base and the vehicle connector will be installed correctly.

[0016] It should be noted that the prescribed tolerance zone may have a dimension of 20 cm to 50 cm, it may be a circle (of the aforementioned diameter) but it may also be another shape. It should be noted that the proposed system can be adapted to target an area smaller than 20 cm.

[0017] It is noted that the magneto-sensitive elements are arranged at a distance from each other, preferably in a horizontal plane of the vehicle and at a Z dimension as low as possible taking into account the ground clearance requirements of the vehicle. Good reception of the magnetic field of interest by the magneto-sensitive elements is maximized.

[0018] It is noted here that the ground clearance can typically be between 120 millimeters and 220 mm, without smaller or larger values ​​being excluded from the principle of the present invention.

[0019] It is also noted that by choosing the direction normal to the ground plane for the axis of the magnetic field, the effect of good reception of the magnetic field signal at the level of the magneto-sensitive elements is maximized.

[0020] According to one embodiment, each of the magneto-sensitive elements provides analog information proportional to the intensity of the received magnetic field. This may be, for example, a single-axis magnetometer component or a multi-axis magnetometer component. It may also be a magnetomechanical system with a rod or weight movable along an axis, the position of the rod or weight being measured by an electronic arrangement, e.g. of the rheostat type or other. The effect perceived by the movable element may be an attraction or a repulsion.

[0021] According to an alternative embodiment, each of the magneto-sensitive elements provides binary or digital information depending on the intensity of the received magnetic field. One or more Reed bulbs with different trigger thresholds can be used; this is a simple, rustic and economical solution.

[0022] According to one embodiment, a single magnetic field emitting element is provided. Thanks to this single magnet, it is a simple, robust and economical solution. A permanent magnet or an electromagnet can be chosen. The permanent magnet emits a magnetic field with a north-south magnet axis aligned with the normal to the ground and the distribution of the field is of revolution around the magnet axis.

[0023] According to one embodiment, four magneto-sensitive elements are provided. For example, two of the four elements can be used to detect the longitudinal position of the vehicle and give maneuvering instructions to the driver (Front or Rear). The other two of the four elements can be used to detect the lateral position of the vehicle and give maneuvering instructions to the driver (Right or Left).

[0024] This covers a tolerance zone of diameter D3 between 20 cm and 50 cm.

[0025] According to one embodiment, the three or four magneto-sensitive elements are arranged in a horizontal plane according to a first polygonal pattern, preferably triangle or square. This is an optimal solution for processing the received signals.

[0026] According to one embodiment, all or part of the zone inside the first polygonal pattern determines an acceptable position with respect to the magnet axis W.

[0027] According to one embodiment, four magnetic field emitting elements are provided. Each emitting element is located opposite each magneto-sensitive element. Cleverly, emitter and receiver pairs (magneto-sensitive element) are thus formed. The ideal position corresponds to a minimum distance for each emitter / receiver pair or to a minimization of the sum of the distances of the emitter / receiver pairs.

[0028] According to one embodiment, the magnetic field emitting elements are arranged in a horizontal plane according to a second polygonal pattern, similar or identical to the first polygonal pattern.

[0029] According to one embodiment, the magnetic field emitting elements are permanent magnets. As a result, there is no need for wire and there is no need for a power supply. Power consumption is zero, there is no need for maintenance. This is a very simple and rustic solution.

[0030] According to one embodiment, the processing unit is an on-board unit, specific or not. The processing unit can directly or indirectly display travel instructions in the form of arrows. For this purpose, either the vehicle's infotainment navigation screen or a driver's multifunction telephone will be used.

[0031] The invention further relates to a method for guiding an electric vehicle driver in a positioning maneuver above a ground-based charging base within a prescribed tolerance, the method comprising: - provide at least one magnetic field emitting element, configured to emit a magnetic field of constant direction and intensity for at least the duration of the maneuver, in a stationary position, on the ground, - receive, via at least three magneto-sensitive elements arranged in the underbody area of ​​the vehicle, the magnetic field emitted by the magnetic field emitting element, the magneto-sensitive elements together supplying signals which are transformed by a processing unit into operating instructions for the driver.

[0032] According to one embodiment, a positive result is delivered when the signals from the magneto-sensitive elements have a received signal level between a predetermined minimum level and a predetermined maximum level, or if the difference between the strongest signal level and the weakest signal level is less than a predetermined threshold.

[0033] In other words, we seek to balance the strength of the signals received by the magneto-sensitive elements, which corresponds to a position of the vehicle which is within the prescribed positioning interval.

[0034] The invention further relates to a motor vehicle comprising a system of guidance as previously described and an underbody charging socket arrangement which can be electrically or electromagnetically coupled with the charging base.

[0035] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which: [Fig.l] is a schematic representation in profile view of a vehicle with an exemplary embodiment of the invention; [Fig.2] illustrates in vertical section a local area of ​​the vehicle underbody with the ground charging base opposite; [Fig.3] schematically illustrates in top view an example with the respective positions of four magneto-sensitive elements; [Fig.4] is similar to [Fig.2] and illustrates an alternative embodiment, with the transmitting element independent of the ground-based charging base; [Fig.5] schematically illustrates in top view an example with three magneto-sensitive elements and their respective positions; [Fig.6] schematically illustrates in top view an example with four magneto-sensitive elements and four magnetic field emitting elements; [Fig.7] shows a timing diagram illustrating the signal levels for two magneto-sensitive elements concerning the longitudinal direction during a maneuver; [Fig.8] schematically illustrates in top view an example with binary magneto-sensitive elements; [Fig.9] schematically illustrates a functional view of the system.

[0036] In the various figures, the same references designate identical or similar elements. For reasons of clarity of the description, certain elements are not necessarily represented to scale.

[0037] We are interested here in an electric motor vehicle VH or a hybrid vehicle equipped, in addition to the thermal engine, with an electric drive train.

[0038] An electrical energy storage battery is provided, referenced 10. The battery may typically be a lithium ion electrochemistry-based battery. The storage battery has a capacity of between 5 kWh (e.g. for hybrids) for hybrids and up to 80 kWh for 100% electric vehicles, without these values ​​constituting limitations.

[0039] Here we have represented a horizontal floor S but of course, the installation can concern the case of an access ramp to a garage for example where the floor is inclined. The floor has a ground plane PS (horizontal or pseudo-horizontal if the floor is inclined) and a normal to the ground W (vertical or pseudo-vertical).

[0040] We define a classic orthonormal reference frame for the vehicle where the longitudinal axis is marked X, the lateral axis is marked Y and the so-called vertical axis is marked Z. Z coincides with the local vertical when the ground is horizontal. The ground normals W and Z are approximately parallel.

[0041] In the context of the present invention, the vehicle VH is equipped with a first electrical coupler C1 provided to cooperate with a ground-based charging base 1 itself equipped with a second electrical coupler C2. The first electrical coupler is connected to the on-board charging monitor by conductors marked 11.

[0042] The presence of a charging comfort function is not incompatible with the possibility of recharging the vehicle battery by means of a conventional cable connected to a charging terminal and connectable to a charging base 12 provided on the vehicle.

[0043] As already indicated in the introductory part, the electrical couplers C1, C2 can be electrical contact and current conduction couplers, or the electrical couplers can be electromagnetic coils without direct electrical mutual contact and operating in the manner of a transformer.

[0044] Whatever the physical coupling mode, two distinct system principles are possible: either the ground-based charging base 1 comprises a telescopic arm which approaches, or even contacts, the connector on board the vehicle, or the connector on board the vehicle descends to come towards the ground-based charging base.

[0045] In both cases, the telescopic kinematics makes it possible to correct imprecise and / or imperfect positioning if it remains within the prescribed tolerance.

[0046] It is also noted that the telescopic kinematics and / or the connection mode makes it possible to compensate for any angular deviation from the vertical axis Z, i.e. a vehicle slightly at an angle relative to a position aligned with the nominal longitudinal direction of the location.

[0047] It follows that the vehicle must be positioned only along the longitudinal axis X and along the lateral axis Y, without regard to orientation.

[0048] Conduction or electromagnetic coupling systems are already available on the market among the products including, among others, the products of the companies Gulplug™, Daze Technology™, Continental™, they are not described in detail here.

[0049] Advantageously, as illustrated according to a first embodiment, a single magnetic field emitting element 2 is provided.

[0050] The emitting element 2 in question may be a permanent magnet or an electromagnet carrying a predetermined current. In [Fig.2], a coil of axis W carrying an electric current has been shown. A permanent magnet positioned in the center of the charging base would be entirely suitable.

[0051] The transmitting element 2 is positioned stationarily in the charging base 1.

[0052] The emitting element 2 is adapted to generate a magnetic field B of constant direction and intensity, with a main north-south orientation coinciding with the direction normal to the local ground W.

[0053] The range of the detectable magnetic field will typically be at least 25 cm, or even 30 cm.

[0054] The intensity of the magnetic field makes it possible to cover a fairly high area which notably covers the ground clearance H1 of the vehicle.

[0055] In my particular example, we choose a permanent Neodymium magnet. The magnetic field produced can be of some tenths of a Tesla, allowing the distance targeted here to be covered.

[0056] According to an alternative presented in [Fig.4], the transmitter element 2 is positioned in a manner connected to the charging base. This configuration proves relevant when the system is offered as add-on equipment, that is to say independently of the equipment of the ground charging station.

[0057] It is typically possible to choose to install the magnet at the rear of the charging base. The magnet may have a thickness close to that of the charging base on the ground, it may have ramps so as to be easily crossed by the wheels of the vehicle.

[0058] Advantageously according to the present invention, as illustrated according to the first embodiment, four magneto-sensitive elements 3 are provided mounted on the vehicle.

[0059] The magneto-sensitive elements 3 are arranged in the underbody area of ​​the vehicle, they are adapted to receive the magnetic field B emitted by the emitting element 2.

[0060] According to one example, the magneto-sensitive elements are inscribed in a circle whose center represents the ideal position of the magnetic field.

[0061] In the example shown in [Fig. 3], a first magneto-sensitive element 31 and a second magneto-sensitive element 32 are located at a distance from each other on an axis parallel to the longitudinal axis X. This is not necessarily the median longitudinal axis of the vehicle; it may be offset to the left or to the right.

[0062] Still in the example shown in [Fig.3], a third magneto-sensitive element 33 and a fourth magneto-sensitive element 34 are located at a distance from each other on an axis parallel to the lateral axis Y.

[0063] The four magneto-sensitive elements are inscribed in a circle of radius R3.

[0064] Additional elements on the operation of the system according to the first embodiment are presented further on in relation to [Fig.7].

[0065] It should be noted that in [Fig.4], the magneto-sensitive elements have positions offset relative to the first coupler C1 of the vehicle, by the same distance which separates the magnetic field emitting element relative to the axis of the ground-based charging base (consistent offset towards the rear of the respective transmitting and receiving parts).

[0066] According to a second embodiment, in the simplest possible version, illustrated in [Fig. 5], the number of magneto-sensitive elements 3 is three. It is noted that with only two magneto-sensitive elements, it is not possible to provide guidance instructions in two directions X and Y in an unambiguous manner.

[0067] A magneto-sensitive element marked 36 is located in a front position, that is to say towards the front, in the axis, and two other magneto-sensitive elements marked 37 and 38 are arranged on either side of the axis towards the rear. It is noted that the magneto-sensitive elements are distributed at 120° each relative to the circle in which they are inscribed.

[0068] It may be provided that the positioning tolerance corresponds more or less to the interior area of ​​the circle, or optionally only a part.

[0069] When the transmitting element is in position 61, this is the ideal centered position. When the transmitting element is in the positions marked 62, 63, 64, 65, the position of the vehicle remains within the permitted tolerance.

[0070] Depending on the decision criteria on the permitted tolerance, the position marked 66 can be considered admissible or not.

[0071] As will be explained later, a position is considered admissible when the signals from the magneto-sensitive elements have a received signal level between a predetermined minimum level and a predetermined maximum level, or alternatively, a position is considered admissible if the difference between the strongest signal level and the weakest signal level is less than a predetermined threshold.

[0072] More precisely, in practice, we seek to balance the strength of the signals received by the magneto-sensitive elements, which corresponds to a position of the vehicle which is within the prescribed positioning interval.

[0073] The further the position of the magnet is from the center of the circle, the more the level of the signals between the three magneto-sensitive elements is different and unbalanced.

[0074] The magneto-sensitive elements 3 may be arranged on a support ring which allows them to be installed as a single piece. The ring in question may also comprise elements for protecting the magneto-sensitive elements from the environment, in particular the underbody environment.

[0075] Generally speaking, the magnetosensitive elements are arranged according to a first geometric pattern. According to the first embodiment the pattern is a square, according to the second embodiment the pattern is a triangle. Generically, the first geometric pattern can be called the first polygonal pattern.

[0076] In [Fig.3], the single emitting element marked 20 here is shown in the center of the circle. So in this configuration, the level of magnetic field signal received by each of the four magneto-sensitive elements is substantially identical.

[0077] If the emitting element is not in the center but is closer to one of the magneto-sensitive elements, then the received field level is higher on this element but it is in fact lower on the more distant or diametrically opposite element.

[0078] [Fig.7] illustrates a timing diagram of a longitudinal maneuver in which the The driver positions his vehicle above the local charging base 1. The upper zone of the diagram represents the position of the transmission lever and the vehicle's travel speed. The lower zone represents the signal levels received by the magneto-sensitive elements relative to the longitudinal axis. The middle zone of the diagram indicates the feedback given to the driver user, in particular the maneuvering instructions.

[0079] Curve N31 represents the signal received by the first magneto-sensitive element 31. Curve N32 represents the signal received by the second magneto-sensitive element 32.

[0080] At the start of the timing diagram, the vehicle advances; the first magnetosensitive element 31 passes above the magnet axis 20; at time t1 we note that the level of the received signal passes through a maximum 71.

[0081] As the vehicle continues to move forward, signal N31 decreases and signal N32 increases between times t1 and t2. At time t2, the second magnetosensitive element 32 passes over the magnet axis.

[0082] At time t3, the driver stops the vehicle, the signal levels are then frozen. The driver shifts the transmission lever from P to N then from N to R. Then the vehicle starts to reverse.

[0083] At time t4, the second magnetosensitive element 32 passes back above the magnet axis, in the opposite direction.

[0084] At time t5, the recoil of the vehicle results in the axis of the magnetic field being slightly removed from the center of the circle of magneto-sensitive elements.

[0085] The dashed lines 72, 73 represent the upper and lower acceptance thresholds, within which the two signals must be found, for the level balancing to be admissible.

[0086] At the location of the zones marked 74 and 75, the condition on the signal level is met and a positive result is delivered to the driver “OK”.

[0087] In [Fig.6] a third embodiment is shown with a configuration with four magnetic field emitting elements 21 22 23 24.

[0088] Each emitting element 21, 22, 23 and 24 is located opposite each magneto-sensitive element respectively 31, 32, 33 and 34.

[0089] Thus, the magnetic field emitting elements are arranged in a horizontal plane according to a second polygonal pattern, similar or identical to the first pattern. polygonal.

[0090] Cleverly, transmitter and receiver pairs (magneto-sensitive element) are thus formed. The ideal position corresponds to a minimum distance for each transmitter / receiver pair or to a minimization of the sum of the distances of the transmitter / receiver pairs.

[0091] [Fig.6] illustrates three examples of relative positioning without index, a second with index A (21A, 22A, 23A and 24A) and a third with index B (21B, 22B, 23B and 24B). In the illustrated example, all three examples are within the required tolerance.

[0092]

[0093] In [Fig.8], according to a fourth embodiment, the magneto-sensitive elements each provide binary information. As already indicated, it may be a Reed bulb. There may simply be four Reed bulbs in all.

[0094] In the example illustrated, there are several Reed bulbs for each equipped location, for example with different trigger thresholds.

[0095]

[0096] Groups 91 and 92 relate to the capture concerning the longitudinal direction of positioning (along X).

[0097] Groups 93 and 94 relate to the capture concerning the lateral direction of positioning (along Y).

[0098] In each group, it is planned to use several Reed bulbs, each with different trigger thresholds. It is thus possible to provide digital information depending on the intensity of the received magnetic field.

[0099] According to a configuration not shown in the figures, a regular horizontal matrix of magneto-sensitive elements providing binary information can be provided, a localized zone in said matrix being activated by the magnetic field received from the transmitting element. The activated localized zone moves as a function of the movement of the vehicle.

[0100] [Fig.9] schematically illustrates a functional view of the system. The unit of The processing can directly or indirectly display travel instructions in the form of arrows. For this purpose, either the vehicle's infotainment navigation screen or a driver's multifunction telephone can be used.

[0101] The processing unit marked 4 is connected by electrical conductors to each of the magneto-sensitive elements. The processing unit 4 can be connected by a wireless link to a multifunction telephone 49. According to another implementation, the processing unit is part of the vehicle equipment and is connected to an infotainment screen 40 of the vehicle.

[0102] The instructions given to drivers can take the form of four arrows as shown in [Fig.9]: forward arrow, backward arrow, right arrow, left arrow, which indicates the position correction to be made.

[0103] The processing unit 4 compares the signals received between the different magneto-sensitive elements, and / or the processing unit 4 compares these signals with respect to predefined configurable thresholds.

[0104] Miscellaneous

[0105] A simplified version with only two magnetosensitive elements for the management of the longitudinal direction only is possible.

[0106] According to an advantageous aspect, it can be provided that the system operates whether the vehicle is moving forward or backward on the ground-based charging station (180° rotation to be compensated by the coupling system).

[0107] If the emitting element is an electromagnet, its electrical excitation can respond to a logic of minimizing consumption. For example, the ground charging base can be equipped with a vehicle presence sensor, e.g. a pulsed infrared sensor, which makes it possible to know if a vehicle is present above the ground charging base, which makes it possible to activate the power supply to the electromagnet.

[0108] The excitation can be interrupted if an effective recharge coupling is achieved or if a maximum excitation time delay has expired.

[0109] Combination of variants

[0110] The genetic person easily understands that all the variants are compatible with each other, mutatis mutandis, namely - permanent magnet or electromagnet, their number and their respective position - number and respective positions of the magnetosensitive elements - processing unit, with functions that are part of the vehicle's own functions or specific processing unit acting as an add-on function.

Claims

Claims

1. Guidance system for managing a positioning of an electric vehicle (EV) above a ground-based charging base (1), within a prescribed tolerance, the positioning being obtained by one or more maneuvers of a driver of the electric vehicle, the system comprising at least one magnetic field emitting element (2), positioned stationarily in the charging base or in a manner connected to the charging base, adapted to generate a magnetic field of constant direction and intensity, the system comprising at least three magneto-sensitive elements (3) mounted on the vehicle arranged in an underbody area of ​​the vehicle, adapted to receive the magnetic field (B) emitted by the magnetic field emitting element, the ground having a ground plane and a ground normal, the emitted magnetic field having a north-south magnet axis aligned with the ground normal and a distribution of revolution around the magnet axis,the system comprising at least one processing unit (4), characterized in that the magneto-sensitive elements together provide signals which are transformed by the processing unit into maneuvering instructions intended for the driver.,

2. Guidance system according to claim 1, characterized in that each of the magneto-sensitive elements (3) provides analog information proportional to the intensity of the received magnetic field.

3. Guidance system according to any one of claims 1 to 2, characterized in that a single magnetic field emitting element (2) is provided.

4. Guidance system according to any one of claims 1 to 3, characterized in that four magneto-sensitive elements (3) are provided.

5. Guidance system according to any one of claims 1 to 4, characterized in that the three or four magneto-sensitive elements are arranged in a horizontal plane according to a first polygonal pattern, preferably triangle or square.

6. Guidance system according to claim 5, characterized in that four magnetic field emitting elements are provided.

7. Guidance system according to any one of claims 1 to 6, characterized in that the magnetic field emitting elements are permanent magnets.

8. Method for guiding an electric vehicle driver in a positioning maneuver above a ground-based charging base within a prescribed tolerance, the method comprising: - providing at least one magnetic field emitting element, configured to emit a magnetic field of constant direction and intensity for at least the duration of the maneuver, in a stationary position, on the ground, - receiving, via at least three magneto-sensitive elements arranged in the underbody area of ​​the vehicle, the magnetic field emitted by the magnetic field emitting element, the magneto-sensitive elements together providing signals which are transformed by a processing unit into maneuvering instruction(s) intended for the driver.

9. Method according to claim 8, characterized in that a positive result is delivered when the signals of the magneto-sensitive elements have a received signal level between a predetermined minimum level and a predetermined maximum level, or if the difference between the strongest signal level and the weakest signal level is less than a predetermined threshold.

10. A motor vehicle comprising a guidance system according to any one of claims 1 to 7 and an underbody charging socket arrangement which can be electrically or electromagnetically coupled with the charging base.

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