METHOD FOR AN ONLINE CALIBRATION, AND CALIBRATION DEVICE

Abstract

A method for online calibration of an environment detection system (12) of an agricultural utility vehicle (10). The method is carried out during operation of the agricultural utility vehicle (10). During a first step, the environment detection system (12) detects the current environment of the agricultural utility vehicle (10). During a further step, current extrinsic calibration parameters are determined on the basis of the current environment (20) detected. Furthermore, a calibration device (14) for carrying out the method and an agricultural utility vehicle (10) with such a calibration device (14) are also described.

Claims

1-10. (canceled)

11. A method for online calibration of an environment detection system (12) of an agricultural utility vehicle (10), the method comprising the following steps to be carried out during the operation of the agricultural utility vehicle (10): detecting (S3) a current environment (20) of the agricultural utility vehicle (10) by the environment detection system (12); and determining (S4) current extrinsic calibration parameters, on a basis of the detected current environment (20), for an online calibration (S5) of the environment detection system (12).

12. The method according to claim 10, further comprising: detecting geometrical features (22) during the detecting step (S3) of the current environment (20) of the agricultural utility vehicle (10), and carrying out the determinating step (S4) on a basis of the detected geometrical features (22).

13. The method according to claim 10, further comprising: extracting linear features (24, 26) from the detected current environment (20), and carrying out the determinating step (S4) on a basis of the extracted linear features (24, 26).

14. The method according to claim 10, further comprising: determinating (S2) a future trajectory (30) of the agricultural utility vehicle (10), determining a curvature of the determined future trajectory (30), and carrying out the determinating step (S4) of current extrinsic calibration parameters as a function of the determined curvature.

15. The method according to claim 14, further comprising: checking (P1) whether the curvature of the determined future trajectory (30) is less than a predefined curvature limit value, and if the curvature determined is less than the predefined curvature limit value, carrying out the determination step (S4) of current extrinsic calibration parameters.

16. The method according to claim 13, further comprising: determinating a quality parameter of the extracted linear features (24, 26), and checking (P2) whether the determined quality parameter is larger than a predefined quality limit value, and if the quality parameter determined is larger than the predefined quality limit value, carrying out the determinating step (S4) of current extrinsic calibration parameters.

17. The method according to claim 10, further comprising: providing the agricultural utility vehicle (10) with an agricultural implement (11), and the environment detection system (12) having at least one sensor fitted on the agricultural implement (11).

18. The method according to claim 10, carrying out the steps during automated travel of the agricultural utility vehicle (10).

19. A calibration device (14), which is designed to carry out the method according claim 11.

20. An agricultural utility vehicle (10) with the calibration device (14) according to claim 19.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG. 1: shows an agricultural utility vehicle with a calibration device according to a respective embodiment.

[0047] FIG. 2: shows a flow chart with process steps for carrying out a method for online calibration of an environment detection system of the agricultural utility vehicle, in accordance with an embodiment of the invention.

[0048] FIG. 3: shows the utility vehicle on an agriculturally useful area after beginning to operate, in order to explain the method.

[0049] FIG. 4: shows the agricultural utility vehicle after it has processed part of the agriculturally useful area, in order to further explain the method.

[0050] FIG. 5: shows the agricultural utility vehicle after a turning maneuver before further processing of another part of the agriculturally useful area, in order to further explain the method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] FIG. 1 shows an agricultural utility vehicle 10 with an agricultural implement 11 installed on it. In this embodiment the agricultural implement 11 is coupled to a rear area of the agricultural utility vehicle 10.

[0052] Two environment detection sensors 13 are arranged at a front area of the agricultural utility vehicle 10. The environment detection sensors 13 form the environment detection system 12 of the agricultural utility vehicle 10. The two environment detection sensors 13 have respective detection ranges 21 which, in this embodiment, are directed in the travel direction of the agricultural utility vehicle 10. The detection ranges 21 cover a partial area of an environment 20 around the agricultural utility vehicle 10. The detection ranges 21 partially overlap. Alternatively or in addition to the embodiment shown in FIG. 1, the environment detection sensors 13 can be arranged at least partially on the agricultural implement 11. In a further embodiment (not shown in FIG. 1), one environment detection sensor 13 is arranged on the agricultural utility vehicle 10 and one is arranged on the agricultural implement 11.

[0053] In addition, a positioning device 16 and a calibration device 14, which are connected to one another, are arranged on the agricultural utility vehicle 10. The positioning device 16 is designed to determine a current position of the agricultural utility vehicle 10. The calibration device 14 is also connected to the two environment detection sensors 13 of the environment detection system 12, in order to read out their detection data and, on the basis thereof, to determine extrinsic calibration parameters of the two environment detection sensors 13 of the environment detection system 12.

[0054] FIG. 2 shows process steps for carrying out a method for the online calibration of the environment detection system 12 of the agricultural utility vehicle 10 shown in FIG. 1. The method is carried out during an operation of the agricultural utility vehicle 10.

[0055] In an initial process step S0, the agricultural utility vehicle 10 begins operating. When beginning its operation, at least one machine (not shown in the figures) of the agricultural utility vehicle 10 is started.

[0056] In a first process step S1 a localization of the agricultural utility vehicle 10 in its environment takes place. In this localization step, a current position of the agricultural utility vehicle 10 is determined.

[0057] On the basis of the position of the agricultural utility vehicle 10 determined in the first process step S1, in a second process step S2 a future trajectory of the agricultural utility vehicle 10 is determined. The future trajectory is determined in order to process an agriculturally useful area by means of the agricultural utility vehicle 10.

[0058] In a subsequent first checking step P1, it is checked whether the future trajectory determined in the second process step S2 is suitable for carrying out an online calibration of the environment detection system 12. As a decision criterion of the first checking step P1, a curvature of the future trajectory determined is considered. If this curvature is less than a predetermined curvature limit value, a further subsequent process step S3 is carried out. If the curvature of the future trajectory is greater than the predetermined curvature limit value, the previous second process step S2 of trajectory determination is again carried out at a later time. At this later time the agricultural utility vehicle 10 will have moved farther along the future trajectory. The second process step S2 and the first checking step P1 are repeated until the decision criterion of the first checking step P1 is fulfilled.

[0059] When the decision criterion of the first checking step P1 is fulfilled, the third process step S3 is carried out. In this third process step S3, the environment 20 is detected by means of the environment detection system 12 arranged on the agricultural utility vehicle 10, i.e., by means of the environment detecting sensors 13. In this step geometrical features in the environment 20 of the agricultural utility vehicle 10 are detected by the environment detection system 12.

[0060] In a second checking step P2, a quality check of the lines detected in the preceding third process step S3 takes place. As the decision criterion of this second checking step P2, a reliability value of one of the geometrical parameters of the lines is used. If this reliability value is above a predefined reliability limit value, the method goes on to a further process step S4. If the reliability is lower than the predetermined reliability limit value, the preceding third process step S3 is repeated. The second checking step P2 and the third process step S3 are repeated until the decision criterion of the second checking step P2 is fulfilled.

[0061] In a fourth process step S4, a calibration parameter determination takes place. In this step, current extrinsic calibration parameters of the environment detection sensors 13 of the environment detection system 12 are determined on the basis of the geometrical features detected in the third process step S3. On the basis of the extrinsic calibration parameters determined in the fourth process step S4, in a further fifth process step S5, an online calibration of the environment detection sensors 13 of the environment detection system 12 is carried out.

[0062] In FIG. 3, the agricultural utility vehicle 10, with the agricultural implement 11, is shown on an unprocessed agriculturally useful area 28. The environment 20 of the agricultural utility vehicle 10 contains, at least in part, the unprocessed agriculturally useful area 28. Geometrical features 22 of the agriculturally useful area 28 are in the travel direction ahead of the agricultural utility vehicle 10. The geometrical features 22 on the unprocessed agriculturally useful area 28 consist of two wheel-ruts 24.

[0063] The wheel-ruts 24 are detected, in the third process step S3, by the environment detection system 12 (not shown in FIGS. 3 to 5). A future trajectory 30, which was determined in the second process step S2, is in the form of a straight trajectory 32. The wheel-ruts 24 are used for determining the current extrinsic calibration parameters of the environment detection sensors 13 of the environment detection system 12 in the fourth process step S4, since the future trajectory 30 is a straight trajectory 32.

[0064] In FIG. 4, the agricultural utility vehicle 10, with its agricultural implement 11, is shown at a later time during the processing of the agriculturally useful area 28. Behind the agricultural utility vehicle 10, relative to the travel direction, now there is a processed agriculturally useful area 28′. Since the vehicle is at the edge of the agriculturally useful area 28, after having driven over the already covered trajectory 30′, it must now carry out a turning maneuver. The future trajectory 30 to be covered for that is now a curved trajectory 34. Further wheel-ruts 24 are now not used for determining the current extrinsic calibration parameters of the environment detection sensors 13 of the environment detection system 12 in the fourth process step S4, since the future trajectory 30 is a curved trajectory 34.

[0065] In FIG. 5, the agricultural utility vehicle 10 with its agricultural implement 11 is shown after having driven over the curved trajectory 34, shown in FIG. 4, as the trajectory 30′ covered. Now in the travel direction ahead of the agricultural utility vehicle 10 there is, besides the further wheel-ruts 24, also a work boundary 26 between the previously processed agriculturally useful area 28′ and the still unprocessed agriculturally useful area 28. Analogously to what was described with reference to FIG. 3, besides the wheel-ruts 24, the agricultural utility vehicle 10 now also detects, with its environment detection system 12, the work boundary 26. From the detected wheel-ruts 24 and the work boundary 26, further linear features are derived, which are now used for determining current extrinsic calibration parameters.

INDEXES

[0066] 10 Agricultural utility vehicle [0067] 11 Agricultural implement [0068] 12 Environment detection system [0069] 13 Environment detection sensor [0070] 14 Calibration device [0071] 16 Positioning device [0072] 20 Environment [0073] 21 Detection range [0074] 22 Geometrical features [0075] 24 Wheel-rut [0076] 26 Work boundary [0077] 28 Agriculturally useful area [0078] 28′ Processed agriculturally useful area [0079] 30 Future trajectory [0080] 30′ Trajectory covered [0081] 32 Straight trajectory [0082] 34 Curved trajectory [0083] P1 Curvature check [0084] P2 Quality check [0085] S0 Start of operation [0086] S1 Localization [0087] S2 Trajectory determination [0088] S3 Environment detection [0089] S4 Calibration parameter determination [0090] S5 Online calibration