Method for adjusting the calibration of an environment sensing sensor based on the determination of a deflection of at least one moving vehicle component of a vehicle

Abstract

The invention relates to a method for adjusting a calibration of at least one environment detection sensor (4) based on the determination of a deflection of at least one movable vehicle component of a vehicle, in particular a driver's cab (1) of a truck, wherein the at least one environment detection sensor (4) is attached to the movable vehicle component, comprising the following steps: - recording (S1) at least a part of the at least one movable vehicle component by means of a sensor device (2, 2a, 2b); - determining (S2) a deflection of the at least one movable vehicle component relative to a horizontal plane, wherein six degrees of freedom are determined when determining the deflection, - adjusting (S3) an extrinsic calibration of the at least one environment detection sensor (4) based on the determined deflection.

Description

[0001] The invention relates to a method for adapting a calibration of an environment detection sensor by determining a deflection of at least one movable vehicle component of a vehicle.

[0002] The measurement of vehicle deflection / pitching is a common practice in automotive engineering. Angle measurements between truck tractors and trailers are also known.

[0003] A disadvantage of the existing methods is that there is currently no solution for determining all six degrees of freedom of movement (x, y, z axes and yaw, pitch, and roll angles) between the driver's cab and the chassis. This information is important for sensor technology installed in the cab to eliminate the cab's own motion as a disturbance.

[0004] It is an object of the present invention to provide a method which enables a precise determination of a deflection of a movable vehicle part and, based thereon, enables an adjustment of a calibration of an environment detection sensor.

[0005] This object is solved by independent claim 1. Further advantageous embodiments and configurations are the subject of the subclaims.

[0006] Initial considerations were that sensors would be installed in the vehicle to implement driver assistance systems or autonomous driving, for example, to detect objects in the vehicle's surroundings. Determining the position of the object relies on the sensors' calibration data. The calibration data is divided into intrinsic and extrinsic data, with the intrinsic data relating to the camera's internal characteristics, and the extrinsic data describing the camera's position in the surroundings.

[0007] Calibration data is particularly important for cameras that cannot measure distance directly. A relatively simple way to determine the distance of objects detected by the camera is to estimate a ground plane using extrinsic calibration and use this to calculate the distance of the objects.

[0008] One problem here, however, is the pitch movement of the ego vehicle, which occurs, for example, when braking or accelerating, since this shifts the position of the ground plane to the sensor and can therefore cause very large errors in the position of the objects.

[0009] This problem is even more pronounced in trucks commonly found in Europe. In addition to the pitch movement caused by the wheel springs, these trucks also experience the movement of the driver's cab. The cab can move in various directions. This can lead to significant difficulties in determining the position of objects detected by sensors on the driver's cab. Cameras, for example, are typically mounted behind the windshield.

[0010] The static calibration of sensors mounted on the driver's cab is negatively affected by the cab's own movement. This leads to a significant deterioration in detection precision and negatively influences the area detected by at least one environment detection sensor.

[0011] Various methods for online calibration are available. Common online calibrations are optimized for passenger cars and can cause problems with larger fluctuations, for example, due to computation time.

[0012] According to the invention, a method for adapting a calibration of an environment detection sensor based on the determination of a deflection of at least one movable vehicle component of a vehicle, in particular a driver's cab of a truck, is proposed, wherein the at least one environment detection sensor is attached to the movable vehicle component, comprising the following steps: - recording at least a part of the at least one movable vehicle component by means of a sensor device; - Determining a deflection of the at least one movable vehicle component relative to a horizontal plane, wherein six degrees of freedom are determined when determining the deflection, - Adjusting an extrinsic calibration of the at least one environment detection sensor based on the determined deflection.

[0013] The at least one environment detection sensor is preferably a mono or stereo camera, a radar, a lidar, or an ultrasonic sensor. It is also conceivable to use multiple environment detection sensors and, accordingly, a combination of multiple identical and / or different sensors. When using multiple sensors, in particular when using multiple different sensors, these can be arranged in a common sensor pod. The orientation of the individual sensors can be determined according to their respective function. For example, a camera in the sensor pod can preferably be aligned in the direction of travel.

[0014] The sensor device is preferably arranged on a stationary part of the vehicle or the driver's cab. It would also be conceivable, in some developments, for the sensor device to be part of the sensor pod together with the surroundings detection sensors. It would also be conceivable for more than one sensor device to be used to determine the deflection. For example, one sensor device could be arranged on a stationary part of the vehicle or the driver's cab, and another sensor device, for example, could be part of a sensor pod on the driver's cab. In this way, various determinations of the deflection can be carried out redundantly, if necessary.

[0015] The method is advantageous in that the determination of the cabin position can be used as additional information for the online calibration of the individual environment detection sensors in order to limit the search area and optimize the computational effort.

[0016] The position of the driver's cab is determined online and used to optimize the extrinsic calibration of the environment detection sensors installed in / on the driver's cab. This improves the detected position of objects.

[0017] In a preferred embodiment, the horizontal plane is a ground plane and is estimated using a sensor that is at least partially aligned with the ground plane. For this purpose, one or more sensors can be attached to a horizontal bar or a sensor pod that is directly connected to the driver's cab. The sensor is intended to estimate the ground plane and thereby determine the position of the driver's cab. The sensor used here is preferably a laser sensor, e.g. LiDAR. For this method, it is helpful if the sensor is aligned as straight downwards as possible. However, sensors that are aligned further forward or backward can also be used. The position of the driver's cab can be determined by the position of the ground plane relative to the driver's cab, and the extrinsic calibration of the other sensors mounted on the driver's cab can thus be adjusted online.An advantage of this embodiment is that the pitch movement caused by the springs on the wheels can also be determined. In this configuration, the environment detection sensor can also be part of the sensor pod and arranged in a housing together with the sensor that detects the ground plane. The orientation of the environment detection sensor is preferably different from the orientation of the sensor.

[0018] In a further preferred embodiment, the horizontal plane is defined by a target which is attached to the movable vehicle component and detected by the sensor. In this embodiment, one or more sensors can be attached, for example, in a sensor pod or on a horizontal bar which is attached to the non-movable part of the driver's cab and is therefore not affected by the movements of the driver's cab. The sensors detect a target. By detecting the position of the target, conclusions can be drawn about the relative position of the driver's cab to the towing vehicle. Various sensors can be used for this purpose. Cameras, for example, can be used, with a specific marking on the driver's cab being applied as a target for better detection. Alternatively, the outline of the driver's cab itself can be used to determine its position.Alternatively, lidars or radars can be used.

[0019] A small corner reflector could be mounted on the driver's cab as a target to facilitate detection. If a sensor pod is installed on the vehicle, the existing sensors in the pod can be used.

[0020] This allows the extrinsic calibration of all sensors installed in the driver's cab itself to be optimized.

[0021] Furthermore, the horizontal plane is preferably defined by a chassis of the vehicle and the sensor device performs a mechanical measurement of the deflection and angle of rotation.

[0022] In a further preferred embodiment, the deflection is determined by means of a three-axis point laser.

[0023] Further advantageous embodiments are shown in the drawings, which show: Fig. 1: a schematic flow diagram of a method according to an embodiment of the invention; Fig. 2: a schematic representation of an advantageous embodiment of the invention; Fig. 3: a schematic representation of a further advantageous embodiment of the invention.

[0024] Fig. 1 shows a schematic flow diagram of a method according to one embodiment of the invention. The method for adapting a calibration of an environment detection sensor based on the determination of a deflection of at least one movable vehicle component of a vehicle, in particular a driver's cab of a truck, wherein at least one environment detection sensor is attached to the movable vehicle component, comprises, in a preferred embodiment, in step S1, recording at least a portion of the at least one movable vehicle component by means of a sensor device. In a step S2, a deflection of the at least one movable vehicle component relative to a horizontal plane is determined, wherein six degrees of freedom are determined when determining the deflection. In a step S3, an extrinsic calibration of the at least one environment detection sensor is adapted based on the determined deflection.

[0025] Fig. Figure 2 shows a schematic representation of an advantageous embodiment of the invention. In the representation of Fig. 2 shows a vehicle, in this case a truck. This truck has a driver's cab 1. A target T is attached to this driver's cab 1 and is detected by a sensor device 2, which in this embodiment consists of a first sensor 2a and a second sensor 2b, which are arranged in a common sensor pod 3. The sensor device 2 is arranged on a stationary part of the driver's cab 1 or the vehicle. The sensors 2a and 2b are aligned such that they can detect the target T on the driver's cab 1. For this purpose, the detection areas Ea and Eb of the respective sensors are aligned accordingly. By detecting the target T, a deflection of the driver's cab 1 can be determined by means of the sensor device 2. This deflection can then be used to detect an environment detection sensor 4, which is arranged on the driver's cab 1 or the vehicle.a moving part of the vehicle.

[0026] In Fig. Figure 3 shows a schematic representation of a further advantageous embodiment of the invention. In this embodiment, the sensor device 2 is arranged in a sensor pod 3.1 together with the environment detection sensor 4 on the driver's cab. The detection area E of the sensor device 2 is aligned such that the sensor device 2 can detect a floor plane B. This allows the deflection of the driver's cab 1 relative to the floor plane B to be determined. List of reference symbols 1 driver's cab 2 Sensor device 2a first sensor of the sensor device 2b second sensor of the sensor device 3 Sensor Pod Sensor Device 3.1 Sensor pod driver's cab 4 Environment detection sensor B Ground level E Detection range sensor device Ea Detection range of the first sensor of the sensor device Eb Detection range of the second sensor of the sensor device T Target S1-S3 process steps

Claims

[1] Method for adjusting a calibration of at least one environment detection sensor (4) based on the determination of a deflection of at least one movable vehicle component of a vehicle, in particular a driver's cab (1) of a truck, wherein the at least one environment detection sensor (4) is attached to the movable vehicle component, comprising the following steps: - recording (S1) at least a part of the at least one movable vehicle component by means of a sensor device (2, 2a, 2b); - determining (S2) a deflection of the at least one movable vehicle component relative to a horizontal plane, wherein six degrees of freedom are determined when determining the deflection, - adjusting (S3) an extrinsic calibration of the at least one environment detection sensor (4) based on the determined deflection. [2] Method according to claim 1, characterized bythat the horizontal plane is a ground plane (B) and is estimated by means of a sensor device (2, 2a, 2b) aligned at least partially with the ground plane (B). [3] Method according to claim 1, characterized by that the horizontal plane is defined by a target (T) which is attached to the movable vehicle component and is detected by means of the sensor device (2, 2a, 2b). [4] Method according to claim 1, characterized by that the horizontal plane is defined by a chassis of the vehicle and the sensor device (2, 2a, 2b) carries out a mechanical measurement of the deflection and angle of rotation. [5] Method according to claim 1, characterized by that the deflection is determined using a three-axis point laser.

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