Arrangement and method for determining the position and orientation of the wheels of a vehicle

Abstract

The invention relates to an arrangement comprising a measuring station (1) with several sensors (2) for detecting measuring marks (4) and several measuring mark carriers (3) to be mounted on the wheels (11) of a vehicle (10) with measuring marks (4) arranged thereon, wherein the measuring marks (4) arranged on different vehicle axles have a height offset relative to each other.

Description

[0001] The invention relates to an arrangement and a method for detecting the position and alignment of the wheels of a vehicle by means of measuring marks mounted on the wheels of the vehicle.

[0002] It is known to fix measuring marks to the wheels of a vehicle and to detect these measuring marks using sensors to determine the position of the wheels or the vehicle's axle position. The sensors are mounted on a beam in front of or behind the vehicle, and the sensors detect the position and orientation of the measuring marks protruding from the sides of the wheels. Based on this, the axle position or the geometric driving axis of the vehicle can be determined, for example.

[0003] A problem with these measuring arrangements is that the sensors currently have to be arranged on a relatively wide measuring beam in order to detect the measuring marks. The measuring marks are located one behind the other in the direction of the vehicle's longitudinal axis, so that, for example, a measuring mark closer to the sensor lies in the horizontal line of sight between the sensor and the measuring mark further away, and is therefore at least partially obscured from the sensor. This obscuration can be eliminated by spacing the sensors further apart, as the measuring marks can be detected at an angle from the outside. However, this leads to a significant widening of the measuring arrangement and thus increased space requirements.

[0004] A further disadvantage is that due to a greater spacing of the sensors relative to each other, it is not possible to detect the measuring marks diagonally from the outside on devices placed to the side of the vehicle, for example the columns of a column lift, because the devices are located in the line of sight between the sensor and the measuring mark which is further away relative to the sensor.

[0005] Based on this, the object of the invention is to provide a measuring arrangement which is compact and which enables the position of the wheels or the axle position of the vehicle to be measured even when devices are arranged to the side of the vehicle.

[0006] This object is achieved by a measuring arrangement having the features of independent patent claim 1. Preferred embodiments are the subject of the dependent claims. A method for detecting the position and alignment of the wheels of a vehicle is the subject of independent patent claim 12.

[0007] According to a first aspect, the invention relates to an arrangement comprising a measuring station with a plurality of sensors for detecting measuring marks and a plurality of measuring mark carriers to be mounted on the wheels of a vehicle with measuring marks arranged thereon. The sensors can be cameras, in particular high-resolution cameras, for example. The measuring mark carriers have a measuring mark carrier center, which is to be arranged on the wheels of the vehicle at the height of the wheel hub center in order to perform a measurement. The measuring marks are arranged on the measuring mark carriers with a height offset relative to this measuring mark carrier center, specifically such that a measuring mark to be arranged on the rear axle has a height offset in a first direction and such that a measuring mark to be arranged on the front axle has a height offset in a second direction, which runs opposite to the first direction.In other words, the measuring marks to be mounted on the front axle and the measuring marks to be mounted on the rear axle protrude in different directions from a wheel hub plane in which the wheel hub centers of the vehicle are located.

[0008] The main technical advantage of the measuring arrangement is that the size of the measuring station can be reduced due to the vertical height offset. This is because the sensors can simultaneously detect the measuring marks arranged on the front axle and rear axle on one side of the vehicle in a horizontal or essentially horizontal detection direction that runs parallel to the central longitudinal axis of the vehicle, as these do not overlap due to the offset. This means that there is no need to detect the measuring marks diagonally from the outside, which means that the width of the measuring station can be significantly reduced. In addition, vehicle measurement can also be carried out if there are measuring devices and / or lifting devices arranged to the side of the vehicle, for example a column of a post lift or the like. This significantly reduces the requirements placed on the measuring environment.In addition, the sensors at the measuring station can be aligned in such a way that they cover a larger area to the side of the vehicle, so that additional measuring marks placed there, which are necessary, for example, for the calibration of vehicle sensors aligned to the side, can also be detected by the sensors.

[0009] According to one embodiment, the measurement mark has a pattern that can be captured by a camera. The pattern can, in particular, comprise multiple geometric shapes. A computer unit designed to calculate the position and orientation of the measurement marks and thus the position and orientation of the vehicle's wheels processes the image information provided by the camera, which contains the pattern, and compares it with a reference pattern. The position and orientation of the vehicle's wheels can be calculated based on the change in the captured pattern relative to the reference pattern.

[0010] According to one exemplary embodiment, a measuring mark to be arranged on the front axle is offset downwards relative to the wheel hub center, and a measuring mark to be arranged on the rear axle is offset upwards relative to the wheel hub center. Alternatively, a measuring mark to be arranged on the front axle is offset upwards relative to the wheel hub center, and a measuring mark to be arranged on the rear axle is offset downwards relative to the wheel hub center. In particular, the vertical spacing is selected such that, with a horizontally aligned line of sight of the sensor, there is no overlap of the measuring marks. These types of vertical offset allow for advantageous detection of the measuring marks with a reduced footprint.

[0011] According to one exemplary embodiment, the height offset is selected such that a measuring mark arranged on the front axle lies completely below a wheel hub plane spanned by the wheel hub centers of the vehicle, and a measuring mark arranged on the rear axle lies completely above this wheel hub plane. This ensures that a measuring mark mounted on the front axle and a rear axle do not overlap when the sensor is in a horizontal line of sight.

[0012] According to an alternative embodiment, the height offset is selected such that a measuring mark arranged on the front axle is located completely above a wheel hub plane spanned by the wheel hub centers of the vehicle, and a measuring mark arranged on the rear axle is located completely below this wheel hub plane. This also ensures that a measuring mark mounted on the front axle and a rear axle do not overlap when the sensor is in a horizontal line of sight.

[0013] According to one embodiment, the measuring mark carrier is designed to be clamped onto a rim of the vehicle. The measuring mark carrier can have three or more arms, by means of which the measuring mark carrier can be clamped onto the outer rim edge of a wheel. This allows the measuring mark to be attached to the outer side of the wheel facing away from the vehicle.

[0014] According to one embodiment, the measuring station comprises a horizontally or substantially horizontally extending measuring beam on which the sensors for detecting the measuring marks are provided. The measuring beam has a width that is greater than the width of the vehicle to be measured, so that the sensors can detect the measuring marks protruding laterally from the wheels. The width of the measuring beam is adapted, for example, to the vehicle width such that the width of the measuring beam corresponds to the vehicle width in the area of ​​the wheels plus the two measuring marks protruding laterally from the wheels.

[0015] According to one embodiment, the measuring beam has a maximum width of 2.8 m, in particular a width between 2.3 m and 2.5 m. This allows common vehicles, in particular passenger cars, to be measured using the measuring station, in such a way that the sensors detect the measuring marks in a line of sight running parallel or substantially parallel to the vehicle's central longitudinal axis.

[0016] According to one embodiment, the sensors for detecting the measurement marks are arranged at a height between 30 cm and 40 cm relative to the ground on which the measuring station is located. In other words, the sensors are located at least substantially at the height of the wheel hub center of the vehicle to be measured. Thus, the measurement marks arranged at the height of the wheel hub center can be detected by the sensors in a horizontal or substantially horizontal line of sight.

[0017] According to one embodiment, a pair of sensors is arranged at the measuring station, one sensor being assigned to each side of the vehicle. The sensors are spaced apart by a distance that is equal to or substantially equal to the distance between the measuring marks arranged on opposite sides of a vehicle axle. This allows for a reduction in the size of the measuring station and a space-saving detection of the measuring marks.

[0018] According to one embodiment, a pair of sensors is arranged at the measuring station. The sensors are spaced a maximum of 2.8 m apart, in particular with a width in the range of 2.3 m to 2.5 m. This allows for the detection of the measuring marks with a reduced measuring station size.

[0019] According to one embodiment, the measuring station comprises a computer unit. A program for determining the position of the measuring marks based on the measurement information provided by the sensors is provided on the computer unit. The program is configured to compensate for the height offset of the measuring marks relative to the wheel hub center. This allows the height offset, which is provided for the unobstructed detection of the measuring marks, to be computationally compensated. That is, after compensation, modified measurement information is obtained, as if the measuring marks were vertically aligned toward the wheel hub center.

[0020] According to a further aspect, a method for detecting the position and alignment of a vehicle's wheels using a measuring station with multiple sensors and multiple measuring mark carriers with measuring marks arranged thereon is disclosed. The method comprises the following steps: - arranging the measuring mark carriers on the wheels of the vehicle, wherein the measuring marks on the measuring mark carriers are arranged offset in height with respect to a measuring mark carrier center, which is to be arranged at the level of the wheel hub center on the respective wheel of the vehicle, so that the measuring marks arranged on different vehicle axles have a height offset relative to one another; - Detecting the measuring marks using the sensors of the measuring station; - Transmitting measurement information provided by the sensors to a computer unit; - Determination of the position and alignment of the vehicle's wheels by the computer unit, compensating for the height offset of the measuring marks.

[0021] The terms “approximately”, “essentially” or “about” mean, in the sense of the invention, deviations from the exact value by + / - 10%, preferably by + / - 5% and / or deviations in the form of changes that are insignificant for the function.

[0022] Further developments, advantages, and possible applications of the invention will become apparent from the following description of exemplary embodiments and from the figures. All described and / or illustrated features, individually or in any combination, are fundamentally part of the invention, regardless of their summary in the claims or their reference back to them. The content of the claims is also incorporated into the description.

[0023] The invention is explained in more detail below with reference to exemplary embodiments and the figures. They show: Fig. 1 a measuring arrangement for measuring the position and alignment of the wheels according to the prior art in a plan view; Fig. 2 shows an example of a measuring arrangement according to the invention for measuring the position and alignment of the wheels in a top view; and Fig. 3 shows an example of the measuring arrangement according to Fig. 2 in a side view.

[0024] The Fig. 1 shows a measuring arrangement according to the prior art. The measuring arrangement comprises a measuring station 1, which is arranged, for example, in front of or behind a vehicle 10. The measuring station 1 is designed to detect measuring marks 4 arranged on the wheels 11 of the vehicle 10 and, based thereon, to determine the geometric driving axis of the vehicle 10. This geometric driving axis is decisively influenced by the position and alignment of the wheels. It is therefore necessary to determine the position and alignment of the wheels 11 using the measuring station 1. It should be noted that the geometric driving axis can differ from the central longitudinal axis MLA of the vehicle 10. The central longitudinal axis MLA is the axis running centrally in the longitudinal direction through the vehicle body, i.e. the axis running between a front body center point and a rear body center point.The geometric driving axis may deviate from this central longitudinal axis MLA of the vehicle 10, in particular if one or more wheels 11 of a vehicle 10 are misaligned.

[0025] As in Fig. 1, at least one measuring mark 4 is assigned to a wheel 11, i.e. in a vehicle 10 with four wheels 11, there are two measuring marks 4 on the front axle 12 and two measuring marks 4 on the rear axle 13. The measuring marks 4 can be arranged on the wheels 11, for example, by means of measuring mark carriers 3. The measuring mark carriers 3 are designed in particular for the clamping attachment of the measuring marks 4 to the rim of the vehicle 10. The measuring mark carrier 3 is configured to space the measuring mark 4 relative to an outer wheel side surface, such that the measuring mark 4 protrudes laterally from the wheel 11.

[0026] According to the prior art, the measuring marks 4 are arranged on the wheels 4 such that the respective measuring mark 4 is arranged on the respective wheel 11, centered on the wheel hub center in the horizontal and vertical direction. In other words, the measuring marks 4 are arranged on the measuring mark carriers 3 with respect to a measuring mark carrier center 3.1, which is to be arranged at the height of the wheel hub center on the wheels 11 of the vehicle 10. The measuring marks can, for example, be 3D measuring marks, via which the wheel position in space (i.e., three-dimensionally) as well as the angular wheel position (e.g., camber) can be measured.

[0027] The measuring station 1 has a measuring beam 1.1, which is preferably horizontal or substantially horizontal and thus extends along the width of the vehicle. Sensors 2 are provided on the measuring beam 1.1, specifically one sensor 2 in the left end region of the measuring beam 1.1 and one sensor 2 in the right end region of the measuring beam 1.1. The sensors 2 are designed to detect the measuring marks 4 arranged on one side of the vehicle. This means that a first sensor detects the measuring marks 4 arranged on the left wheels of the vehicle 10, and a second sensor detects the measuring marks 4 arranged on the right wheels of the vehicle 10. The sensors 2 can be cameras, for example.

[0028] Since the measuring marks 4 in the prior art are arranged at the same height on the front axle 13 and the rear axle 14, it is necessary that the distance d of the sensors 2, as in Fig. 1, is significantly greater than the vehicle width or the distance between the measuring marks 4 arranged on the front axle 13 and rear axle 14, so that the sensors 2 can be aligned obliquely from the outside of the vehicle side and thus detect the measuring marks 4 obliquely from the front. The width b of the measuring bar 1.1 must therefore be significantly greater than the width of the vehicle 10, for example 3 m or greater. An arrangement of the sensors 2 at the height of the respective measuring marks, ie a horizontally measured distance between the sensors 2 relative to one another that is equal to or substantially equal to the distance between the measuring marks 4 arranged on the front axle 13 and rear axle 14 is not possible with this configuration, since the measuring marks 4 arranged on the front axle 13 cover the measuring marks 4 of the rear axle 14.

[0029] Fig. 2 and Fig. 3 show a measuring arrangement according to the invention. The following only describes the differences between the measuring arrangement of these figures and the measuring arrangement of Fig. 1. Furthermore, the details described above also apply to the measuring arrangement according to Fig. 2 and Fig. 3.

[0030] As can be seen from the summary of Fig. 2 and Fig. 3, the measuring marks 4 are arranged in the area of ​​the wheel hub center of the respective wheel 11 when viewed horizontally (see the top view of the Fig. 2). In the vertical direction, however, the measuring marks 4 are offset from the wheel hub center or from the wheel hub plane RE, specifically the measuring marks 4 of the front axle 13 are offset in the opposite direction to the measuring marks 4 of the rear axle 13. In other words, the measuring marks 4 on the measuring mark carriers 3 are arranged at a height offset with respect to the measuring mark carrier center 3.1, which is to be arranged at the height of the wheel hub center on the wheels 11 of the vehicle 10. For example, the measuring marks 4 of the front axle 13 have a defined offset from the wheel hub center, measured in the vertical direction, and are thus arranged lower than the wheel hub center. The measuring marks 4 of the rear axle 14, on the other hand, also have a defined offset from the wheel hub center, measured in the vertical direction, and are thus arranged higher than the wheel hub center.In other words, the measuring marks 4 of the front axle 13 and the rear axle 14 are arranged offset in different directions in the vertical direction, so that when the sensors 2 are arranged at a distance d relative to one another that corresponds at least substantially to the distance between the two measuring marks 4 arranged on the front axle 13 or on the rear axle 14, the measuring mark 4 mounted on the rear axle is not obscured by the measuring mark 4 mounted on the front axle. It is understood that the prescribed vertical offset can also be implemented in the opposite way, i.e., the measuring mark 4 mounted on the front axle is arranged higher than the measuring mark 4 mounted on the rear axle.

[0031] Due to the vertical offset of the measuring marks 4 mounted on the front axle compared to the measuring marks 4 mounted on the rear axle, the sensors 2 can be mounted on the measuring beam 1.1 in such a way that they detect the measuring marks 4 in a direction parallel or substantially parallel to the central longitudinal axis MLA of the vehicle 10, and the detection direction of the sensor 2 is horizontal or substantially horizontal. This allows, on the one hand, the measuring beam 1.1 of the measuring station to be significantly reduced in width, which offers advantages with regard to the required installation space. On the other hand, the measuring arrangement can also be used, for example, with column lifts, each of which has a lifting column arranged laterally next to the vehicle. In the case of an oblique detection from the front or rear, as is the case in Fig.As shown in Figure 1, the lifting column obscures the measuring mark 4, which is located further away from the measuring station 1. With a vertically offset arrangement of the measuring marks 4, the sensors 2 can detect the measuring marks 4 in an area between the vehicle side surface and the lifting column of the column lift. The vertical offset of the measuring marks 4 also allows the sensors 2 to be mounted at a lower height, thus reducing the overall height of the measuring station 1.

[0032] The measuring station 1 has a computing unit 1.2, which is coupled to the sensors 2 and receives measurement information from these sensors 2. The computing unit 1.2 comprises a program for detecting the position and orientation of the wheels 11 of the vehicle 10. The program can be designed to calibrate sensors of a driver assistance system of the vehicle 10, wherein the program determines the geometric driving axis of the vehicle 10, which is based on the position and orientation of the wheels 11 of the vehicle 10.

[0033] The program of the computing unit 1.2 is designed to compensate for the offset of the measuring marks 4. For this purpose, a value can be set or predefined in the program, which defines the offset of the measuring marks 4 of the front axle 13 and the rear axle 14. This value, stored for the respective axle, can be calculated with the vertical position of the measuring mark determined by the sensor. In particular, the value can be added to or subtracted from the vertical position value. This allows the offset of the measuring marks 4 to be calculated out by the program. If, for example, the measuring marks 4 of the front axle 13 are offset 10 cm downwards with respect to the wheel hub center and the measuring marks 4 of the rear axle 14 are offset 10 cm upwards with respect to the wheel hub center, the measured position of a measuring mark mounted on the front axle can be corrected by adding or subtracting the offset value of 10 cm to the measured value.The correction of the measured value of the measuring mark 4 mounted on the rear axle 14 can be carried out in the reverse manner.

[0034] The invention has been described above using exemplary embodiments. It is understood that numerous changes and modifications are possible without departing from the scope of protection defined by the patent claims. List of reference symbols 1 measuring station 1.1 Measuring bar 1.2 Computing unit 2 sensors 3 measuring mark carriers 3.1 Measuring mark carrier center 4 measuring marks 10 vehicles 11 wheels 12 front axle 13 Rear axle b width d distance RE wheel hub center MLA central longitudinal axis of the vehicle

Claims

[1] Arrangement comprising a measuring station (1) with a plurality of sensors (2) for detecting measuring marks (4) and a plurality of measuring mark carriers (3) to be mounted on the wheels of a vehicle (10) with measuring marks (4) arranged thereon, characterized by that the measuring marks (4) on the measuring mark carriers (3) are arranged at a height offset with respect to a measuring mark carrier center (3.1), which is to be arranged at the level of the wheel hub center on the wheels (11) of the vehicle (10), in such a way that a measuring mark (4) to be arranged on the rear axle (13) has a height offset in a first direction and that a measuring mark (4) to be arranged on the front axle (12) has a height offset in a second direction, which runs opposite to the first direction. [2] Arrangement according to claim 1, characterized bythat a measuring mark (4) to be arranged on the front axle (12) is arranged offset downwards relative to the wheel hub centre and a measuring mark (4) to be arranged on the rear axle (13) is arranged offset upwards. [3] Arrangement according to claim 1, characterized by that a measuring mark (4) to be arranged on the front axle (12) is arranged upwards relative to the wheel hub center and a measuring mark (4) to be arranged on the rear axle (13) is arranged downwards relative to the wheel hub center. [4] Arrangement according to one of claims 1 or 2, characterized by that the height offset is selected such that a measuring mark (4) arranged on the front axle (12) lies completely below this wheel hub plane (RE) in relation to a wheel hub plane (RE) spanned by the wheel hub centers of the vehicle (10), and a measuring mark (4) arranged on the rear axle (13) lies completely above this wheel hub plane (RE). [5] Arrangement according to one of claims 1 or 3, characterized bythat the height offset is selected such that a measuring mark (4) arranged on the front axle (12) lies completely above this wheel hub plane (RE) in relation to a wheel hub plane (RE) which is spanned by the wheel hub centers of the vehicle (10), and a measuring mark (4) arranged on the rear axle (13) lies completely below this wheel hub plane (RE). [6] Arrangement according to one of the preceding claims, characterized by that the measuring mark carrier (3) is designed to be clamped onto a rim of the vehicle. [7] Arrangement according to one of the preceding claims, characterized by that the measuring station (1) has a horizontally or substantially horizontally extending measuring bar (1.1) on which the sensors (2) for detecting the measuring marks (4) are provided. [8] Arrangement according to claim 7, characterized by that the measuring beam (1) has a maximum width (b) of 2.8 m. [9] Arrangement according to one of the preceding claims, characterized by that a pair of sensors (2) is arranged at the measuring station (1) and that the sensors (2) are spaced apart (d) from one another which is equal to or substantially equal to the spacing between the measuring marks (4) arranged on opposite sides of the vehicle on a vehicle axle. [10] Arrangement according to one of the preceding claims, characterized by that a pair of sensors (2) is arranged at the measuring station (1) and that the sensors (2) are spaced apart from each other by a maximum of 2.8 m. [11] Arrangement according to one of the preceding claims, characterized bythat the measuring station (1) has a computer unit (1.2) and that the computer unit (1.2) comprises a program for determining the position of the measuring marks (4) based on the measurement information provided by the sensors (2), wherein the program is configured to compensate for the height offset of the measuring marks (4) relative to the wheel hub center. [12] Method for detecting the position and alignment of the wheels of a vehicle (10) by means of a measuring station (1) with a plurality of sensors (2) and a plurality of measuring mark carriers (3) with measuring marks (4) arranged thereon, the method comprising the following steps: - arranging the measuring mark carriers (3) on the wheels of the vehicle (10), wherein the measuring marks (4) on the measuring mark carriers (3) are arranged offset in height with respect to a measuring mark carrier center, which is to be arranged at the level of the wheel hub center on the respective wheel (11) of the vehicle (10), so that the measuring marks (4) arranged on different vehicle axles have a height offset relative to one another; - detecting the measuring marks (4) by means of the sensors (2) of the measuring station (1); - transmitting measurement information provided by the sensors (2) to a computer unit (1.2); - Determination of the position and alignment of the wheels of the vehicle (10) by the computer unit (1.2) while compensating for the height offset of the measuring marks (4).

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