Sensor for detecting position

Abstract

To provide a sensor that outputs a position on a passage extending in a passage direction with a minimum possible measurement error.SOLUTION: A sensor 9 includes a transmitter element 16, a measurement transducer 18, and an evaluation device 21. The transmitter element has at least one magnet (39) disposed at a center, and two magnets (37) disposed at an edge portion. Magnetic poles (35 and 36) of the magnets (37 and 39) are aligned in a lateral direction (22) with respect to a passage direction (24), and are set to generate a magnetic field generated by a transmitter 17 changing in the passage direction. The transmitter element and the measurement transducer are disposed so as to move to each other in the passage direction, and are installed so as to output a sensor signal (19) depending on a relative position between the measurement transducer and the transmitter element, on the basis of a measurement signal 20. The magnet disposed at the center is disposed to excite a magnetic flux larger than that of the magnets disposed at the edge portion.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sensor for detecting a position on a passage extending in a passage direction and a vehicle provided with the sensor.

Summary of the Invention

Problems to be Solved by the Invention

[0002] It is an object of the present invention to specify a sensor for detecting a position on a passage extending in a passage direction, which sensor outputs the detected position with a minimum possible measurement error.

Means for Solving the Problems

[0003] This object is achieved by the features of the independent claims. Preferred embodiments are the subject matter of the dependent claims.

[0004] According to one aspect of the present invention, a sensor for detecting a position on a passage extending in a passage direction includes a transmitter element, a measurement transducer, and an evaluation device. The transmitter element has at least one magnet arranged at the center and two magnets arranged at the edges before and after the magnet arranged at the center when viewed in the passage direction. The magnetic poles of the magnets are aligned laterally with respect to the passage direction and are arranged to emit a magnetic field generated by a transmitter that changes in the passage direction. The measurement transducer is arranged to emit a measurement signal that depends on the magnetic field generated by the transmitter reaching the measurement transducer. The transmitter element and the measurement transducer are arranged to be movable relative to each other in the passage direction. The evaluation device is arranged to output a sensor signal that depends on the relative position between the measurement transducer and the transmitter element based on the measurement signal. The magnet arranged at the center is arranged to excite a larger magnetic flux than the magnets arranged at the edges when viewed in the passage direction.

[0005] The specified sensor is based on the idea that when the transmitter element moves relative to the measurement transducer, the field vector of the magnetic field reaching the measurement transducer rotates about the horizontal axis, and the idea that the direction of the field vector reaching the measurement transducer is a measure suitable for determining the relative position of the transmitter element with respect to the measurement transducer and thus the detected position. However, the magnitude of the field vector is not constant along the path. These fluctuations in the field vectors ultimately lead to measurement errors in the detected position.

[0006] In order to keep the magnitude of the field vector as constant as possible along the path, as many short magnetic poles as possible can be arranged side by side along the path. However, if during measurement the magnetic pole located at the center of the transmitter element as seen in the path direction is longer than the magnetic poles located at the ends of the transmitter element as seen in the path direction, it can be seen that the magnitude of the field vector can be kept more constant along the path.

[0007] Therefore, the specified sensor outputs the position on the path extending in one path direction with a small measurement error. Compared to a transmitter element that requires a large number of short-distance magnetic poles to keep the field vector as constant as possible, the specified sensor can be manufactured at a lower cost and with less required installation space because it has significantly fewer magnetic poles.

[0008] In an embodiment of the specified sensor, the magnet arranged at the center to excite a larger magnetic flux is 30% - 60%, preferably 40% - 50%, particularly preferably 44% larger than each magnet arranged at the edge. If the magnets arranged at the edge are too short in the path direction, their effects are too small. If they are too long, as described above, their effects cannot achieve a field vector that is as constant as possible. For a given configuration, the effects of the magnets arranged at the edge interacting with the magnet arranged at the center are optimal for achieving a field vector that is as constant as possible.

[0009] In a further embodiment of the specified sensor, when viewed in the passage direction, one transition magnet is arranged on the transmitter element in front of and behind the magnet arranged in the center, followed by a magnet arranged at the edge when viewed in the passage direction. Interacting with the magnet arranged in the center, the transition magnet encodes the passage and provides a higher resolution than the detectable positions via the passage.

[0010] In a particular embodiment of the specified sensor, the transition magnet is smaller than or equal to the magnet arranged in the center, but larger than the magnet arranged at the edge. In this way, it is ensured that the above effect of obtaining a field strength as constant as possible on the passage is achieved.

[0011] In a preferred embodiment of the specified sensor, the measurement range for detecting the position when viewed in the passage direction is between the transition magnets. This embodiment is based on the idea that the magnitude of the field strength vector always changes greatly towards the edge of the transmitter element as viewed in the passage direction. The highest possible constancy of the field strength vector is mainly achieved towards the center of the transmitter element as viewed in the passage direction. For this reason, the center of the transmitter element is a particularly advantageous position for utilizing the idea following the specified sensor.

[0012] In another embodiment, the specified sensor includes a further measurement transducer. The further measurement transducer is arranged in front of or behind the measurement transducer when viewed in the passage direction and is installed to output a further measurement signal that depends on the magnetic field generated by the transmitter that reaches the measurement transducer. The transmitter element and the further measurement transducer are arranged so as to be movable relative to each other in the passage direction. The evaluation device is installed to output the sensor signal based on the difference between the two measurement signals. In this way, the interference average value can be filtered from the measurement signal, and the error in position detection can be further reduced.

[0013] In a particularly preferred embodiment of the specified sensor, one of the magnets arranged at the edge is at least partially within the measurement range for detecting the position. Tests have shown that within this range, in combination with the differential measurement described above, the error of the specified sensor can be significantly reduced again.

[0014] In another embodiment of the specified sensor, since the passage direction is the tangential direction, the detected position is the angular position.

[0015] According to another aspect of the present invention, a vehicle includes a chassis movable in a driving direction, two front wheels that support the chassis in front as viewed in the driving direction, two rear wheels that support the chassis behind as viewed in the driving direction, a steering wheel for rotating a steering shaft around a rotation axis to turn the front wheels, one of the sensors for detecting a relative position between a portion of the steering shaft facing the steering wheel and a portion of the steering shaft facing the front wheels, and a motor for adjusting the turning of the front wheels according to the detected relative position.

Brief Description of the Drawings

[0016] The above-described characteristics, features, and advantages of the present invention, as well as the manner in which they are achieved, will become more apparent in connection with the following description of embodiments that will be described in more detail in relation to the drawings.

Figure 1

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DETAILED DESCRIPTION OF THE INVENTION

[0017] In the drawings, the same technical elements are given the same reference numerals and are described only once. The drawings are purely schematic and in particular do not reflect actual geometric ratios.

[0018] Please refer to FIG. 1, which is a schematic perspective view of a vehicle 1 including a steering system 2.

[0019] In the example of this embodiment, the vehicle 1 includes a chassis 5 supported by two front wheels 3 and two rear wheels 4. Since the front wheels 3 can be turned by the steering system 2, the vehicle 1 can be driven around a curve.

[0020] The steering system 2 includes a steering wheel 6. The steering wheel 6 is mounted on a first steering shaft 7, and the first steering shaft 7 is then pivotally mounted around a rotation axis 8. The first steering shaft 7 is guided here by a sensor 9 to detect the position in the form of an angular position and is further connected to a torsion element 10 in a manner not further specified. A second steering shaft 11 is connected to the torsion element 10 on the opposite side of the first steering shaft 7 on the rotation axis 8 and ends at a steering gear 12. When the steering wheel 6 turns with a torque in the form of a steering torque 13, the steering torque 13 is accordingly transmitted through the steering shafts 7 and 11 to the steering gear 12, and the steering gear 12 steers the front wheels 3 in a curve having a wheel angle 14 accordingly.

[0021] The steering process is supported by an auxiliary motor 15 that assists the second steering shaft 11 during turning. For this purpose, the steering torque 13 is derived from the relative angular position between the first steering shaft 7 and the second steering shaft 11 detected by the sensor 9. Next, the auxiliary motor 15 steers the second steering shaft 11, among other things, in accordance with the detected steering torque 13.

[0022] To detect the above angular position and thus the steering torque 13, the sensor 9 includes a magnetic transmitter element 16 connected to the first steering shaft 7 that induces a magnetic field 17. The sensor 9 further includes a measuring transducer 18 connected to the second steering shaft 11, and the measuring transducer 18 receives the magnetic field 17 from the magnetic transmitter element 16 and transfers a measurement signal 20 that depends on the received magnetic field to an evaluation device 21 as a function of the relative angular position of the first steering shaft 7 with respect to the second steering shaft 11, and thus of the magnetic transmitter element 16. Thus, the measurement signal 20 bears the angular position detected as information. The evaluation device 21 determines the relative angular position of the two steering shafts 7 and 11 based on the measurement signal 20 and outputs a sensor signal 19 that depends on this and thus also on the elasticity of the torsion element 10 and thus on the steering torque 13. Thus, since the sensor signal 19 depends directly on the detected steering torque 13, the auxiliary motor 15 can directly process this information to turn the second steering shaft 11.

[0023] Please refer to FIG. 2 showing the version of the sensor 9.

[0024] In the description of the sensor 9, a space within a cylindrical coordinate system spanning the axial direction 22, the radial direction 23, and the circumferential direction 24 is assumed. The axial direction 22 is aligned with the direction of the rotation axis 8, and the circumferential direction 24 is aligned circumferentially around the rotation axis 8. The radial direction 23 extends radially with respect to the rotation axis 8.

[0025] In this cylindrical coordinate system, the sensor 9 includes a first bearing bush 25 extending around the rotation axis 8 for the force fit receptacle of the first steering shaft 7 and a second bearing bush 26 for the force fit receptacle of the second steering shaft 11.

[0026] In this case, the first bearing bush 25 has a holding member 27 to which the magnetic field transmitter element 16 is attached, for example, by an adhesive. In this way, the magnetic field transmitter element 16 is held stationary on the first steering shaft 7 when the first steering shaft 7 is pushed into the first bearing bush 25.

[0027] The carrier 28 is formed here in the form of a flange on the second bearing bush 26. The printed circuit board holder 30 is held on the carrier 28 by pins 29 supported on the floating bearing element 31 on the opposite side when viewed in the axial direction 22. The evaluation device 21 in the form of a printed circuit board is received in the printed circuit board holder 30. Next, the measurement transducer 18 is electrically and mechanically connected thereto, for example, by soldering. The measurement signal 20 from the measurement transducer 18 is processed by the evaluation device 21 by the electronic component 32 and transferred as a sensor signal 19 to the auxiliary motor 15 via an interface that is not visible in FIG. 2.

[0028] During operation of the sensor 9, when the first steering shaft 7 rotates and the rotation is transmitted to the second steering shaft 11 via the torsion element 10, the first bearing bush 25 held on the first steering shaft 7 by a force fit rotates together with the magnetic field transmitter element 16, and the second bearing bush 26 held on the second steering shaft 11 rotates together with the measurement transducer 18. Due to the inertia of the second steering shaft 11 and the elasticity of the torsion element 10, the first steering shaft 7 is twisted with respect to the second steering shaft 11 when the first steering shaft 7 turns. As a result, the magnetic field transmitter element 16 also rotates with respect to the measurement transducer 18 in the circumferential direction 24 as the passage direction.

[0029] The magnetic field 17 of the magnetic field transmitter element 16 changes in the circumferential direction 24. Therefore, when the magnetic field transmitter element 16 rotates with respect to the measurement transducer 18, the magnetic field 17 reaching the measurement transducer 18 changes. The rotation of the magnetic field transmitter element 16 with respect to the measurement transducer 18, and thus the position detected by the sensor 9 on the path running in the circumferential direction 24, depends on the magnitude of the steering torque 13 due to the elasticity of the torsion element 10. Therefore, the magnetic field 17 reaching the measurement transducer 18, the measurement signal 20, and finally the sensor signal 19 also depend on the magnitude of the steering torque 13.

[0030] The magnetic field transmitter element 16 is designed in the form of a magnetic ring segment guided circumferentially about the rotation axis 8 with a radial ring spacing 33. The measurement transducer 18 is also arranged such that the radial ring distance 33 is at a distance from the rotation axis 8, so that the magnetic field transmitter element 16 and the measurement transducer 18 overlap radially. In FIG. 2, the centers of these elements in the extension of the radial direction 23 are selected as reference points for determining the radial ring distance 33 of the measurement transducer 18 and the magnetic field transmitter element 16. In addition to the radial overlap, the magnetic field transmitter element 16 is arranged at an axial measurement distance 34 from the measurement transducer 18.

[0031] With reference to FIG. 3, which shows a schematic diagram of a partial configuration of the sensor 9 for the steering system described above with reference to FIG. 1, the structure of the magnetic field transmitter element 16 will be described in more detail below.

[0032] Here, the magnetic field transmitter element 16 is composed of five individual magnets arranged in the circumferential direction 24 as the passage direction. The individual magnets are dipoles of a north pole 35 and a south pole 36. The dipoles are oriented axially in the axial direction 22 across the circumferential direction 24, and thus are oriented transversely with respect to the circumferential direction 24. The orientation of the consecutive dipoles in the circumferential direction 24 is reversed axially 22 in each case, so that the magnetic field transmitter element 16 is installed to emit a magnetic field generated by a transmitter that changes in the circumferential direction 24.

[0033] Hereinafter, the individual magnets located on the outer side when viewed in the circumferential direction 24 are called the magnets 37 arranged at the edge, and the individual magnets adjacent to the magnets 37 arranged at the edge are called the transition magnets 38. All other individual magnets that are on the opposite side of the magnet 37 arranged at the edge and are connected to the transition magnet 38 are hereinafter called the magnets 39 arranged at the center. In the embodiment of FIG. 3, the magnetic field transmitter element 16 has, but is not limited to, only a single magnet 39 arranged at the center.

[0034] In the embodiment of FIG. 3, the individual magnets 37, 38, and 39 have different lengths when viewed in the circumferential direction 24 as the passage direction. Starting from the length 40 of the magnet 39 arranged at the center as viewed in the circumferential direction 24, the two magnets 37 arranged at the edge as viewed in the circumferential direction 24 have a length 41 that is shorter than the length 40 of the magnet arranged at the center. Assuming that the magnet 39 arranged at the center and the two magnets 37 arranged at the edge are equally magnetized, the magnet 39 arranged at the center thus excites a larger magnetic flux than either of the two magnets 37 arranged at the edge.

[0035] The weaker magnetic flux excitation of the magnet 37 arranged at the edge can in principle also be achieved in another way, for example, by magnetizing the magnet 37 arranged at the edge weaker than the magnet 39 arranged at the center. A combination of the two aforementioned designs for the weaker magnetic flux excitation of the magnet 37 arranged at the edge compared to the magnet 39 arranged at the center is also possible.

[0036] The idea behind weakening the magnetic flux excitation of the magnet 37 arranged at the edge compared to the magnet 39 arranged at the center will be explained in more detail hereinafter with reference to FIGS. 4 to 6.

[0037] First, FIG. 4 shows the case where all the individual magnets 37, 38, 39 excite the same magnetic flux. This means that all the individual magnets 37, 38, 39 have the same length and are equally magnetized. This is desirable from an economic point of view because the magnetic field transmitter element 16 can be assembled from uniform standard elements.

[0038] Please refer to FIG. 1 above. In FIG. 1, it has been described that the magnetic field 17 reaching the measurement transducer 18 determines the information in the measurement signal 20 that explains the detected angular position. This information should be as linearly related as possible to the detected angular position. It has been proven that the phase 43 of the magnetic field 17 reaching the measurement transducer 18 is suitable for this purpose only under the condition that the magnitude 44 of the magnetic field 17 reaching the measurement transducer 18 is constant over the circumferential direction 24.

[0039] FIG. 4 shows the curve 45 of the magnitude 44 of the magnetic field 17 reaching the measurement transducer 18 over the circumferential direction 24 for a magnetic field transmitter element 16 composed of all individual magnets 37, 38, 39 that excite the same magnetic flux, but which is composed of the magnet 39 arranged at the center, two transition magnets 38, and two magnets arranged at the edge 37, as shown in FIG. 3.

[0040] Such a magnetic field transmitter element 16 saves installation space, but the course 45 of the magnitude 44 of the magnetic field 17 reaching the measurement transducer 18 is not constant at any point in the circumferential direction 24. As a result, when the angular position is detected via the phase 43 of the magnetic field 17 reaching the measurement transducer 18, distinct non - linearities are introduced into the measurement. To correct these non - linearities, filters are required if possible, and computing resources are required to implement them.

[0041] One way to keep the magnitude 44 of the magnetic field 17 reaching the measurement transducer 18 constant in a part of the circumferential direction 24 is shown in FIG. 5. For this purpose, the magnetic field transmitter element 16 shown in FIG. 4 is simply supplemented by an additional magnet 39 arranged at the center. In this way, the magnitude 44 of the magnetic field 17 reaching the measurement transducer 18 can be kept constant at least in the region of the innermost - centered magnet 39 as seen in the circumferential direction 24. This is shown by the course 45' above the magnetic field transmitter element 16 in FIG. 5.

[0042] However, an installation space that is unnecessary for implementation is required.

[0043] An alternative solution implemented also in the sensor 9 of FIG. 2 is sketched in FIG. 6. Here, the magnet 39 arranged in the center, as compared to the magnets 37 arranged at the edge, extends in the circumferential direction 24 and thus excites a larger magnetic flux than the magnets arranged at the edge. With this solution, the magnitude 44 of the magnetic field 17 reaching the measurement transducer 18 can be kept constant in the region of the magnet 39 arranged in the center. This is shown by the course 45” above the magnetic field transmitter element 16 of FIG. 6.

[0044] The idea described above of keeping the magnitude 44 of the magnetic field 17 reaching the measurement transducer 18 constant with a non-uniform magnetic flux when viewed in the circumferential direction 24 will be explained in more detail below by comparison of the measurement results shown in FIG. 7.

[0045] In FIG. 7, the error value 46 is plotted in a coordinate system over the circumferential direction 24. To record the error value 46, the second steering shaft 11 is fixed and the first steering shaft 7 rotates in the circumferential direction 24 and with respect to the circumferential direction 24 with respect to the second steering shaft 11. In this way, any relative angular position between the first and second steering shafts 7, 11 can be set in the circumferential direction 24.

[0046] The error value 46 accounts for the difference between the measured value of the actual relative angular position detected by the sensor 9 and the actual relative angular position between the two steering shafts 7, 11 in the circumferential direction 25.

[0047] In FIG. 7, the error value 46 is plotted with the dashed error curve 47 that occurred when the magnetic field transmitter element 16 according to FIG. 4 was used for the sensor 9. In this magnetic field transmitter element 16, the individual magnets 37, 38, and 39 each had an extension of 12° in the circumferential direction 24, providing a total extension of 60° in the circumferential direction 24. The magnetic field transmitter element 16 further extended 15.5 mm to 21.5 mm in the radial direction 23 and had a height of 5 mm in the axial direction 22. The measurement transducer 18 was arranged 18.5 mm in the radial direction 23 and 1.5 mm in the axial direction 22 above the magnetic field transmitter element 16.

[0048] In FIG. 7, the error value 46 is plotted with the solid error curve 48 that occurred when the magnetic field transmitter element 16 according to FIG. 3 was used for the sensor 9. In this magnetic field transmitter element 16, the centrally arranged magnet 39 and the transition magnet 38 each had an extension of 12° in the circumferential direction 24, and the edge - arranged magnets 37 each had an extension of 9°, again providing a total extension of 54° in the circumferential direction 24. Regarding the detection of the dashed error curve 47, the magnetic field transmitter element 16 further extended 15.5 mm to 21.5 mm in the radial direction 23 and had a height of 5 mm in the axial direction 22. The measurement transducer 18 was arranged 18.5 mm in the radial direction 23 and 1.5 mm in the axial direction 22 above the magnetic field transmitter element 16.

[0049] The difference between the dashed error curve 47 and the solid error curve 48 is shown by the dotted difference curve 49.

[0050] From the comparison of the two error curves 47 and 48 and the difference curve 49, it is immediately apparent that the magnetic field transmitter element 16 with the edge - arranged magnets 37 made shorter compared to the centrally arranged magnet 39 can be used over a very large angular range with a relatively small measurement error. Thereby, such a magnetic field transmitter element 16 is designed to be more compact in the circumferential direction 24.

[0051] Figures 8 and 9 are used to explain the effect of the magnetic field transmitter element 16 as described in the differential measurement in FIGS. 3 to 6. For this purpose, the configuration from FIG. 3 is extended by a further measurement transducer 18' spaced 30° in the circumferential direction 24 from the measurement transducer 18. All other configurations from FIG. 3, in particular the geometric dimensions, are retained.

[0052] In the differential measurement, the measurement signal 20 of one measurement transducer 18 is subtracted from the measurement signal of the other measurement transducer 18' (not shown) to determine the sensor signal 19. Similar to FIG. 7, error curves 47 and 48 and a differential curve 49 for the differential measurement of the relative angular position between the two steering shafts 7, 11 are plotted in FIG. 9.

[0053] From the error curves 47 and 48 and the differential curve 49, it is immediately apparent that the error in the region of the transition magnet 38 seen in the rotational direction 24 towards the magnet 37 arranged at the edge can be almost canceled out by the use of the magnetic field transmitter element 16 with the magnet 37 arranged at the edge with attenuated magnetic flux.

Claims

1. A sensor (9) for detecting a position on a passage extending in a passage direction (24) in the circumferential direction around a rotation axis (8), a transmitter element (16) having a magnet (39) arranged in the center and two magnets (37) arranged at the front and rear edges of the magnet (39) arranged in the center when viewed in the passage direction (24), wherein the magnetic poles (35, 36) of the magnets (37, 39) are aligned in a lateral direction (22) with respect to the passage direction (24), and the transmitter element (16) is installed so as to generate a magnetic field (17) generated by the transmitter element (16) that varies in the passage direction (24); a measurement transducer (18) arranged to output a measurement signal (20) that depends on the magnetic field (17) generated by the transmitter element (16) reaching the measurement transducer (18), wherein the transmitter element (16) and the measurement transducer (18) are arranged so as to be movable relative to each other in the passage direction (24) a measurement transducer (18); the measurement transducer (18) is arranged to overlap the transmitter element (16) with an axial measurement distance; an evaluation device (21) installed to output a sensor signal (19) that depends on the relative position between the measurement transducer (18) and the transmitter element (16) based on the measurement signal (20); and when viewed in the passage direction (24), the magnet (39) arranged in the center is arranged to excite a larger magnetic flux than each magnet (37) arranged at the edge, the length along the passage direction (24) of the magnet (39) arranged in the center is 30% to 60% larger than the length along the passage direction (24) of each magnet (37) arranged at the edge, the sensor (9).

2. The length along the passage direction (24) of the magnet (39) arranged at the center for exciting a larger magnetic flux is 40% to 50% larger than the length along the passage direction (24) of each magnet (37) arranged at the edge, and the sensor (9) according to claim 1 is characterized in that.

3. One transition magnet (38) is arranged in the transmitter element (16) before and after the magnet (39) arranged at the center when viewed in the passage direction (24), and then a plurality of magnets (37) arranged at the edge when viewed in the passage direction (24) follow, and the sensor (9) according to claim 1 is characterized in that.

4. The transition magnet (38) is smaller than or equal to the magnet (39) arranged at the center and larger than the plurality of magnets (37) arranged at the edge, and the sensor (9) according to claim 3 is characterized in that.

5. The measurement range for detecting the position viewed from the passage direction (24) is between two transition magnets (38) along the passage direction (24), and the sensor (9) according to claim 3 is characterized in that.

6. A measurement transducer (18') arranged in front of or behind the measurement transducer (18) when viewed in the passage direction (24) and outputting a further measurement signal depending on the magnetic field (17) generated by the transmitter (17) reaching the measurement transducer, further including a measurement transducer (18'), the transmitter element (16) and the further measurement transducer (18') are arranged so as to be movable relative to each other in the passage direction (24), and the evaluation device (21) is arranged to output the sensor signal (19) based on the difference between two measurement signals (20), and the sensor (9) according to claim 4 is characterized in that.

7. One of the plurality of magnets (37) arranged at the edge is at least partially in the measurement range for detecting the position viewed from the passage direction (24), and the sensor (9) according to claim 5 is characterized in that.

8. Each of the magnets (37) disposed on the edge portion and its adjacent transition magnet (38) are within the measurement range, the sensor (9) according to claim 7, characterized in that.

9. The passage direction (24) is a circumferential direction around the rotation axis (8) such that the detected position is an angular position, the sensor (9) according to claim 7, characterized in that.

10. A chassis (5) movable in the driving direction, Two front wheels (3) that support the chassis (5) in front when viewed in the driving direction, Two rear wheels (4) that support the chassis (5) behind when viewed in the driving direction, A steering wheel (6) for rotating a steering shaft (7, 11) around a rotation axis (8) to turn the front wheels (3) A sensor (9) according to claim 3 for detecting a relative position between a portion (7) of the steering shaft facing the steering wheel (6) and a portion (11) of the steering shaft facing the front wheels, A motor (15) for adjusting the turning of the front wheels (3) according to the detected relative position, a vehicle (1), characterized in that it comprises.

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