DEVICE FOR MEASURING THE STEERING WHEEL POSITION, THE STEERING WHEEL ANGLE, AND/OR THE INCLINATION OF THE STEERING WHEEL OF A VEHICLE

Abstract

A device for detecting a steering wheel position, the steering wheel angle and/or the inclination of the steering wheel (304) of a vehicle is disclosed. The device includes at least two cameras (5, 6; 202, 203) by means of which the steering wheel (304) can be sensed (8, 9; 204, 205). At least three reference objects (301, 302, 303) are provided which can be releasably fastened to the steering wheel (304).

Claims

1. Device for detecting the steering wheel position, the steering wheel angle and/or the inclination of the steering wheel (304) of a vehicle, characterized in that the device comprises at least two cameras (5, 6; 202, 203) by means of which the steering wheel (304) can be sensed (8, 9; 204, 205), wherein at least three reference objects (301, 302, 303) are provided which can be releasably fastened to the steering wheel (304).

2. Device according to claim 1, characterized in that, in the case of the releasable fastening, two (302, 303) of the at least three reference objects (301, 302, 303) are configured to in each case be fastened in the upper transition of a crosspiece (305) in the steering wheel (304) to the steering wheel rim (306) of the steering wheel (304) or at a defined distance to this transition with a defined direction to this transition, wherein one of said two reference objects (302) is configured to be fastened on the left-hand side of the crosspiece (305.1) of the steering wheel (304) and the other of said two reference objects (303) can be fastened on the right-hand side of the crosspiece (305.2) of the steering wheel (304), wherein said two reference objects (302, 303) can be distinguished from the at least one further reference object (301).

3. Device according to claim 2, characterized in that reference aids are part of the device, which are configured in such a way that in the mounted state, they are arranged outside the periphery of the steering wheel and which are in each case associated with one of the two reference objects (302, 303), which are configured to in each case be fastened in the upper transition of a crosspiece (305) in the steering wheel (304) to the steering wheel rim (306) of the steering wheel (304) or at a defined distance to this transition, such that the connecting line (307) between the two reference aids coincides with or extends in parallel with the connecting line (307) of the two reference objects (302, 303) mentioned.

4. Device according to any of claims 1 to 3, characterized in that the device comprises a frame (308) for the three reference objects (30,1 302, 303), wherein the three reference objects (301, 302, 303) are interconnected by means of the frame (308), wherein the frame (308) consists of three longitudinal elements (310, 311, 312) that are interconnected, at a common center point (309), at one of the ends thereof, wherein the reference objects (301, 302, 303) are in each case resiliently fastened at the other end of the longitudinal elements (310, 311, 312), in order to push the reference objects (301, 302, 303) in the longitudinal direction of the longitudinal elements (310, 311, 312).

5. Device according to claim 4, characterized in that, when the three reference objects (301, 302, 303) are fastened to the steering wheel (304), the center point (309) of the frame (308) is located above the connecting line (307) of the two bottom reference objects (302, 303).

6. Device according to any of claims 1 to 5, characterized in that the two cameras (202, 203) are arranged on the same side of the vehicle, outside the vehicle (1).

7. Device according to claim 6, characterized in that each of the two cameras (202, 203) in each case has a solid angle that allows for a steering wheel to be detected by both cameras (202, 203), either on the right-hand side of the vehicle (2) or on the left-hand side of the vehicle (3), wherein both cameras (202, 203) detect the same steering wheel (2, 3).

8. Device according to any of claims 1 to 5, characterized in that the two cameras (5, 6) are arranged on different sides of the vehicle, wherein each of the two cameras (5, 6) in each case has a solid angle (8, 9) that allows for a steering wheel (2, 3) to be detected by both cameras (5, 6), both on the right-hand side of the vehicle and on the left-hand side of the vehicle.

9. Method for detecting the steering wheel position, the steering wheel angle and/or the inclination of the steering wheel (304) of a vehicle, characterized in that the steering wheel (304) is sensed by at least two cameras (5, 6; 202, 203), wherein the at least two cameras (5, 6; 202, 203) can detect at least three reference points (301, 302, 303) on the steering wheel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] An embodiment of the invention is shown in the drawings, in which:

[0058] FIG. 1: is a plan view of a vehicle which is shown, in a schematic view, both as a right-hand drive and as a left-hand drive vehicle, comprising a first camera assembly,

[0059] FIG. 2: is a plan view of a vehicle which is shown, in a schematic view, both as a right-hand drive and as a left-hand drive vehicle, comprising a second camera assembly,

[0060] FIG. 3: is a first view showing the attachment of three reference objects to a steering wheel, in a plan view of the steering wheel, and

[0061] FIG. 4: is a further view showing the attachment of three reference objects to a steering wheel, in a side view of the steering wheel.

DETAILED DESCRIPTION

[0062] FIG. 1 is a plan view of a vehicle 1 which is shown, in a schematic view, both with a steering wheel 2 at the right side (right-hand drive vehicle) and with a steering wheel 3 at the left vehicle side (left-hand drive vehicle), comprising a first camera assembly 4 that consists of a camera 5 on the right-hand side of the vehicle and a camera 6 on the left-hand side of the vehicle. The travel direction of the vehicle is denoted by the arrow 7.

[0063] It can be seen that the cameras 5 and 6 each have a solid angle 8 and 9, respectively, that is of such a magnitude that each of said two solid angles 8 and 9, respectively, includes both the right-hand steering wheel 2 and the left-hand steering wheel 3.

[0064] The intersection 10 of the two solid angles 8 and 9 is shown shaded in FIG. 1.

[0065] It is thus possible to perform 3D-evaluation of the camera images, in the region of the intersection 10, using the two cameras 5, 6.

[0066] FIG. 2 is a plan view of a vehicle which is shown, in a schematic view, both both with a steering wheel 2 at the right side (right-hand drive vehicle) and with a steering wheel 3 at the left vehicle side (left-hand drive vehicle), comprising a second camera assembly 201.

[0067] Said camera assembly 201 comprises two cameras 202 and 203 which each detect a solid angle 204 and 205, respectively. Said two solid angles 204 and 205 again have a common intersection 206 that is shown shaded.

[0068] It can be seen that the two solid angles 204 and 205 are arranged, with respect to the size and orientation thereof, such that the left-hand steering wheel 3 is located in said two solid angles and thus also in the intersection 206 of said two solid angles 204 and 205.

[0069] It is thus possible to detect said left-hand steering wheel 3 using the camera assembly 201.

[0070] The right-hand steering wheel 2 is located outside the solid angles 204 and 205.

[0071] In order for it to be possible to also detect the right-hand steering wheel 2, it would be possible to provide a second camera assembly (not shown here) that could be arranged on the right-hand side of the vehicle. Said camera assembly would likewise comprise two cameras. The solid angles of said cameras would enclose the right-hand steering wheel 2.

[0072] Alternatively, the camera assembly 201 could also be displaceable, for example so as to be movable on the right-hand side of the vehicle into a defined position and a defined orientation of the solid angles thereof such that the right-hand steering wheel 2 can be detected.

[0073] It would alternatively also be conceivable to design the camera assembly 201 so to be rotatable such that the solid angles thereof capture the right-hand steering wheel 2 as a result of the rotation.

[0074] FIG. 3 is a first view showing the attachment of three reference objects 301, 302, 303 to a steering wheel 304, in a plan view of the steering wheel. The three reference objects 301, 302, 303 can be releasably fastened to the steering wheel 304.

[0075] It is possible to determine the position of the three reference objects 301, 302, 303 in space, using a camera assembly consisting of two cameras. The plane in which said three reference objects 301, 302, 303 are is defined by the position of said three reference objects 301, 302, 303 in space. As a result, the plane of the steering wheel 304 is also defined, because the reference objects 301, 302, 303 are clearly fastened to the steering wheel 304 relative to said steering wheel plane.

[0076] It can be seen that two (302, 303) of the at least three reference objects 301, 302, 303 are in each case arranged in the region of the upper transition of a crosspiece 305 in the steering wheel 304 to the steering wheel rim 306, wherein one of said two reference objects 302 can be fastened on the left-hand side of the crosspiece 305 and the other of said two reference objects 303 can be fastened on the right-hand side of the crosspiece 305. The crosspiece 305 consists of the two parts 305.1 and 305.2, which each proceed from the circle 313 around the central shaft of the steering wheel 304.

[0077] Steering wheels 304 generally comprise a crosspiece 305 by means of which the steering wheel rim 306 is fastened to the central shaft of the steering wheel 304. Above said crosspiece 305, the steering wheel 304 is generally open towards the steering wheel rim 306. This makes it possible for the vehicle driver to keep the display elements, in the instrument cluster of the dashboard, in view in the event of a “straight position” of the steering wheel 304 or a small steering wheel angle. The steering wheels 304 optionally also have a connection element 314, from the central shaft of the steering wheel 304 downwards towards the steering wheel rim 306.

[0078] It can be seen that the steering wheel rim 306 does not extend in a circular manner on the lower face (in the straight position of the steering wheel 304), but instead cuts the (imaginary) circular continuation of the steering wheel rim 306 in the manner of a secant. It can also be seen that, owing to being attached above the crosspiece 305, the three reference objects 301, 302, 303 are not influenced by this geometrical shape of the steering wheel 304.

[0079] In the embodiment shown, the two reference objects 302, 303 are each attached at a defined point of the steering wheel 304. Furthermore, in the case of conventional steering wheels 304 said two points are axisymmetric with respect to a center line in the steering wheel plane, which line extends through the center point of the steering wheel 304, in the vertical direction (i.e. from the lowest point of the steering wheel rim to the uppermost point of the steering wheel rim).

[0080] This means that, in the case of an optimally adjusted steering wheel 304, the connecting line 307 of said two reference objects 302, 303 extends horizontally in the event of straight travel. The inclination of said connecting line 307 relative to the intersection lines resulting between a horizontal plane and the steering wheel plane determined by all three reference objects is the steering wheel angle.

[0081] This makes it possible to determine whether the steering wheel angle corresponds to the target value thereof. The steering wheel angle generally corresponds to the target value thereof when the connecting line 307 of the two reference objects 302, 303 corresponds extends horizontally in the event of a steering angle of the wheels of the vehicle that corresponds to straight travel.

[0082] During an evaluation of the two reference objects 302, 303 in conjunction with the third reference object 301, the plane of the steering wheel can be determined.

[0083] It can furthermore be seen that the three reference objects 301, 302, 303 are interconnected by means of a frame 308. The frame 308 consists of three longitudinal elements 310, 311, 312 that are interconnected, at a common center point 309, at one of the ends thereof. The reference objects 301, 302, 303 are in each case fastened at the other end of the longitudinal elements 310, 311, 312, such that the reference objects 301, 302, 303 can in this case be pushed in the longitudinal direction of the longitudinal elements 310, 311, 312. Said fastening can advantageously be resilient. A worker can thus easily fasten the frame 308, comprising the reference objects 301, 302, 303, to a steering wheel 304.

[0084] Since the two reference objects 302, 303 are each attached to the steering wheel at a defined position, the steering wheel angle can be determined from said two reference objects 302, 303, taking account of the third reference point 301. In order to further determine the position of the plane of the steering wheel 304, it is not necessary for the third reference object 301 to be attached to the steering wheel at a defined position. For this evaluation, said reference object 301 can for example also be attached so as to be offset relative to the axis of symmetry of the steering wheel, as can be seen in the drawing in FIG. 3.

[0085] This embodiment of the frame 308 comprising the resilient attachment of the reference objects 301, 302, 303 provides a simple possibility for achieving the releasable fastening of the three reference objects 301, 302, 303 to the steering wheel 304. The reference objects 301, 302, 303 can in addition also be shaped so as to be substantially cylindrical and so as to be mounted so as to be rotatable about the central axis of the cylinder. The lateral surface of the cylinder may correspond to the inner face of the inner portion of a torus that has been cut open in the manner of a circle.

[0086] Since the steering wheel rim is toroidal, a particular advantage of an embodiment of this kind is that the relevant reference object 301, 302, 303 is in contact with the steering wheel rim 306 at a defined position.

[0087] Even if the shape of the reference objects 301, 302, 303 is less optimally adapted to the geometrical shape of the steering wheel rim 306, the resilient mounting results in the reference objects 310, 302, 303 being pressed onto the steering wheel rim 306 in a defined manner.

[0088] It can furthermore be seen that the center point 309 of the frame 308 is located above the connecting line 307 of the two bottom reference objects 302, 303.

[0089] Geometrical constraints, resulting from the conventional design of steering wheels 304, can thus advantageously be taken into account. It is frequently the case in steering wheels that the crosspiece 305 does not extend exactly horizontally, but instead that the crosspiece 305 consists of two elements 305.1 and 305.2 which extends obliquely downwards, proceeding from the center point of the steering wheel 304. It is furthermore often the case that the center point of the steering wheel 304 is formed as a circle 313 in which for example the actuation element for the horn is integrated. The width of the crosspiece 305 is therefore often less than would correspond to the diameter of the circle 313 of the steering wheel 304 around the center point.

[0090] The described geometrical design and arrangement of the frame 308 makes it possible to take account of this, but wherein the two corresponding reference objects 302, 303 can nonetheless each be arranged in the region of the upper transition of the crosspiece 305.1, 305.2 in the steering wheel to the steering wheel rim 306.

[0091] In this embodiment, the frame 308 is advantageously spaced apart both from the crosspiece 305 and from the circle 313 around the center point of the steering wheel 304, such that the frame 308 (and thus also the reference objects 301, 302, 303) can be easily assembled and detached again.

[0092] FIG. 4 is a further view showing the attachment of the reference objects 301, 303 to a steering wheel 304, in a side view of the steering wheel.

[0093] It can be seen in FIG. 4 that the reference objects 301, 303 (the reference object 302 is hidden in this case by the reference object 303 and cannot be seen, but is nonetheless present) span a plane 401 that is in parallel with the plane 402 of the steering wheel 304.

[0094] Owing to the adaptation to the basic structure of different types of steering wheel, the device can be used in a flexible manner. This is advantageous in particular also because various steering wheels exist that can be installed for the individual vehicle types, depending on the vehicle configuration. Owing to the adaptation of the device to the fundamental elements of the structure of the steering wheel, the device can be used in a flexible manner.

[0095] The reference objects are advantageously designed with respect to color (e.g. a pattern) and shape so as to provide the greatest possible contrast to the surroundings.

[0096] The inclination of the steering wheel and the steering wheel angle can be determined using image processing methods of photogrammetry.

[0097] Calibration of the system can take place either by means of a specific reference object arrangement having a defined pattern and a defined position, or by means of arranging the reference object arrangement in a defined position. The reference object arrangement relates to the arrangement of the three reference objects.