Method and device for aligning a calibration device

Abstract

A method for aligning a calibration device for calibrating a vehicle environmental sensor of a vehicle, and a device for carrying out such a method. The method includes: measuring a temporal curve of at least one measurement point using the camera, determining the geometrical driving axis from the temporal curve of the at least one measurement point, measuring a first and a second lateral distance value of the vehicle using the distance sensors at a measurement time, determining a center of a vehicle axle at the measurement time on the basis of the ascertained lateral distance values, correlating the geometrical driving axis to the center of the vehicle axle at the measurement time and determining an axially centric geometrical driving axis, and aligning the calibration device in correspondence to the ascertained axially centric geometrical driving axis.

Claims

1. A method for aligning a calibration device for calibrating a vehicle environmental sensor of a vehicle using a device that has a camera, a first distance sensor and a second distance sensor, the method comprising: measuring a temporal curve of at least one measurement point using the camera, wherein the temporal curve is a measurement at a plurality of time points, wherein from the measurements at the plurality of time points, a movement pattern during the overall time of the measurement is determined; determining a geometrical driving axis from the temporal curve of the at least one measurement point; measuring a first lateral distance value and a second lateral distance value of the vehicle using the first distance sensor and the second distance sensor at a measurement time; determining a center of a vehicle axle at the measurement time based on the ascertained first and second lateral distance values; correlating the geometrical driving axis to the center of the vehicle axle at the measurement time and determining an axially centric geometrical driving axis; and aligning the calibration device in correspondence to the ascertained axially centric geometrical driving axis.

2. The method as recited in claim 1, wherein an artificially situated feature is used as the at least one measurement point.

3. The method as recited in claim 2, wherein a retroreflective measurement mark is the feature.

4. The method as recited in claim 1, wherein a natural feature of the vehicle is used as the at least one measurement point.

5. The method as recited in claim 1, wherein the measurement of the first and second lateral distance values is synchronized with a measurement frequency of the camera.

6. The method as recited in claim 1, wherein a reference point of the geometrical driving axis and/or the center of the vehicle axle is ascertained at the measurement time through a linear interpolation.

7. The method as recited in claim 1, wherein the first and second distance sensors are oriented to a same height above a roadway.

8. The method as recited in claim 1, wherein the first and second lateral distance values are determined parallel to a roadway.

9. The method as recited in claim 1, wherein the first and second distance sensors each measure a distance from one another before and/or after the measurement time, and the measured distances are compared with one another.

10. The method as recited in claim 1, wherein at least one of the first and second lateral distance values is measured using a laser distance measuring unit.

11. The method as recited in claim 1, wherein a measured distance of each of the first and second distance sensors from a corresponding wheel of the vehicle are used as the first and second lateral distance values.

12. A device, comprising: a camera configured to acquire a temporal curve of at least one measurement point, wherein the temporal curve is a measurement at a plurality of time points, wherein from the measurements at the plurality of time points, a movement pattern during the overall time of the measurement is determined; a first distance sensor and a second distance sensor configured to acquire first and second lateral distance values of a vehicle; an evaluating device configured to determine a geometrical driving axis, a center of a vehicle axle, and an axially centric geometrical driving axis; and a calibration device configured to calibrate a vehicle environmental sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a plan view of an exemplary embodiment of a device for carrying out the method according to the present invention for aligning a calibration device.

(2) FIG. 2 shows a side view of the device of FIG. 1 for carrying out the method according to the present invention for aligning a calibration device.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(3) FIG. 1 shows a plan view of an exemplary embodiment of a device 10 for carrying out the method according to the present invention for aligning a calibration device 14. The goal of the method is to position calibration device 14 in front of a vehicle 18 in such a way that a vertical center axis 22, or a defined feature (not shown) of an axially centric geometrical driving axis 26, is intersected. Axially centric geometrical driving axis 26 here corresponds to a geometrical driving axis 30 that has its reference point in a center 34 of a vehicle axle, so that the axially centric geometrical driving axis 26 and geometrical driving axis 30 are parallel to one another. A vehicle environmental sensor 38 of vehicle 18 cannot be calibrated until such a configuration is present.

(4) In order to determine the axially centric geometrical driving axis 26, device 10 has a camera 42 that is positioned in front of vehicle 18. This camera 42 acquires a temporal curve of a measurement point 46 that, in the depicted exemplary embodiment, is a feature artificially situated on vehicle 18. On the basis of the temporal curve of measurement point 46, an evaluating device 50 ascertains geometrical driving axis 30 of vehicle 18. The position and alignment of camera 42 in a measurement station system 52 are known to evaluating device 50.

(5) In addition, the device has a first and a second distance sensor 54, 58. These distance sensors 54, 58 are situated opposite to one another, at a distance A, and, when vehicle 18 drives by, correspondingly measure a first and a second lateral distance value d1, d2 that indicate a distance from vehicle 18 lateral to the direction of travel. The position and orientation of distance sensors 54, 58 in measurement station system 52 are known to evaluating device 50.

(6) These lateral distance values d1, d2 are subsequently communicated to evaluating device 50, so that evaluating device 50 can determine the center 34 of the vehicle axle from these values. The ascertained geometrical driving axis 30 and center 34 of the vehicle axle are subsequently correlated to one another in evaluating device 50, so that the axially centric geometrical driving axis 26 becomes capable of being determined. Corresponding to the determined axially centric geometrical driving axis 26, in a next step calibration device 14 can be aligned.

(7) FIG. 2 shows a side view of device 10 according to FIG. 1 for carrying out the method according to the present invention for aligning calibration device 14. FIG. 2 shows that camera 42 records, with a frequency of measurement, images 62 between a beginning of measurement t.sub.0 and an end of measurement t.sub.i. In the depicted exemplary embodiment, distance sensors 54, 58 measure the lateral distance values d1, d2, at the same height H parallel to a roadway 66, of measurement station system 52 for a respective wheel 70 traveling past, which in this case are wheels 70 of a rear axle 74 (see FIG. 1) of vehicle 18.

(8) In the exemplary embodiment, the measurement frequencies of distance sensors 54, 58 are synchronized with the measurement frequency of camera 42. When wheels 70 move past, lateral distance values d1, d2 ascertained by distance sensors 54, 58 change. This is shown in the corresponding diagrams for distance sensors 54, 58.

(9) Due to the change in distance, evaluating device 50 detects the moving past of the corresponding wheel 70. At a measurement time t.sub.k, ascertained here as the center time between a first and last measurement value t.sub.1, t.sub.2 for the wheel, the corresponding image 62 of camera 42 is used and the reference point, corresponding to this image 62, of geometrical driving axis 30 is ascertained. Subsequently, geometrical driving axis 30 is correlated to the center 34 of the vehicle axle ascertained at measurement time t.sub.k, so that axially centric geometrical driving axis 26 is ascertained.

(10) On the basis of axially centric geometrical driving axis 26 ascertained at measurement time t.sub.k, evaluating device 50 can determine axially centric geometrical driving axis 26 at a measurement end time t.sub.i. Calibration device 14 can be aligned corresponding to this axially centric geometrical driving axis 26 ascertained at measurement end t.sub.i in order to calibrate vehicle environmental sensor 38 of vehicle 18.