Method for operating a sensor device for a motor vehicle, corresponding sensor device and computer program product

Abstract

The invention relates to a method for operating a sensor device for a motor vehicle (1), wherein the sensor device has at least one reflection sensor (2) by means of which environmental data describing an environment (8) of the motor vehicle (1) is detected at least temporarily. Provision is made for an angle of inclination of the motor vehicle (1) to be determined independently of the environmental data, and for the reflection sensor (2) to be calibrated as a function of the determined angle of inclination. The invention further relates to a sensor device for a motor vehicle (1) and a computer program product.

Description

[0001] The invention relates to a method for operating a sensor device for a motor vehicle, wherein the sensor device has at least one reflection sensor by means of which environmental data describing the environment of the motor vehicle are at least temporarily acquired. The invention further relates to a sensor device for a motor vehicle and a computer program product.

[0002] For example, the prior art includes German patent application DE 10 2021 105 823 A1. This describes a method for controlling a vehicle with a lidar device, the method comprising: recording lidar data from the lidar device by a controller on board the vehicle while the vehicle is traveling on a straight road; determining, by the controller, that the vehicle is traveling straight on the straight road; detecting, by the controller, straight lane markings on the straight road; calculating lidar orientation parameters by the controller based on the straight lane markings; calibrating the lidar device by the controller based on the lidar orientation parameters; and controlling the vehicle by the controller based on data from the calibrated lidar device.

[0003] Furthermore, EP 4 283 332 A1 discloses a system and a method for performing lidar self-calibration. The system comprises a lidar sensor mounted on a vehicle. During operation, the lidar sensor receives a lidar reference signal based on a plurality of reference objects corresponding to the vehicle and determines a tilt angle of the lidar sensor based on the lidar reference signal. The tilt angle is then decomposed into several isolated angles, for example, a pitch angle, a roll angle, and a yaw angle. For each of the isolated angles, the lidar sensor determines a corresponding offset between the lidar sensor and the vehicle based on a corresponding calibration criterion and performs compensation based on the offset. This achieves self-calibration of the lidar sensor.

[0004] The object of the invention is to propose a method for operating a sensor device for a motor vehicle which has advantages over known methods, in particular ensuring high accuracy of the environmental data determined using the reflection sensor by taking into account the orientation of the motor vehicle.

[0005] According to the invention, this is achieved by a method for operating a sensor arrangement for a motor vehicle with the features of claim 1. It is provided that an inclination angle of the motor vehicle is determined independently of the environmental data and that the reflection sensor is calibrated depending on the determined inclination angle.

[0006] Advantageous embodiments with expedient further developments of the invention are specified in the dependent claims. It should be noted that the exemplary embodiments described in the description are not limiting; rather, any variations of the features disclosed in the description, the claims, and the figures are possible.

[0007] The method serves to operate the sensor device. The sensor device is preferably an integral part of the motor vehicle, but can of course also exist separately, particularly until the sensor device is mounted on or in the motor vehicle. The sensor device is designed and configured to detect the environment or surroundings of the motor vehicle using at least one sensor, preferably several sensors. At a minimum, the sensor device includes a reflection sensor for this purpose.

[0008] A reflection sensor is an active sensor that emits an output signal into its environment and receives the reflected signal, particularly from an obstacle, as an input signal. Reflection sensors exist, for example, as radar sensors, sonar sensors, or LiDAR sensors. Radar sensors use electromagnetic waves, sonar sensors use sound waves, and LiDAR sensors use light to detect the environment, especially to identify obstacles. Sonar sensors, for instance, are ultrasonic sensors, meaning they use sound waves in the ultrasonic range. The reflection sensor provides environmental data, for example, to a control unit of the sensor device or the vehicle, describing the vehicle's surroundings. Specifically, this environmental data includes information about the obstacle(s) present in the environment.

[0009] For example, it is intended that the vehicle will be driven, at least temporarily, based on environmental data captured by the reflection sensor. This means, in particular, that longitudinal and / or lateral guidance of the vehicle will be carried out based on this environmental data, especially by the aforementioned control unit. Longitudinal guidance includes, for example, controlling a drive system and / or a braking system of the vehicle to adjust the actual speed of the vehicle to a target speed selected based on the environmental data.

[0010] The lateral control of the vehicle includes, in particular, steering the vehicle, i.e., adjusting the actual steering angle to a target steering angle, which in turn is selected based on environmental data. The environmental sensing device can therefore serve to enable autonomous or at least semi-autonomous driving. However, it can also be designed to display the environmental data to the vehicle's user, especially to assist the user in maneuvering the vehicle, for example, while parking or exiting a parking space.

[0011] Due to its operating principle, the reflection sensor has a relatively small viewing window. This viewing window has, for example, a first opening angle and a second opening angle in two perpendicular directions, with the first opening angle being smaller than the second. For example, the first opening angle is at most 20%, at most 10%, or at most 5% of the second opening angle. However, the first angle can be significantly smaller, for example, at most 3%, at most 2%, or at most 1% of the second opening angle.

[0012] The first opening angle is determined in the vertical direction of the vehicle, and the second opening angle in the transverse direction. The first opening angle is thus determined in a plane that completely encompasses both the longitudinal and vertical axes of the vehicle, whereas the second opening angle is determined in an imaginary plane that completely encompasses both the longitudinal and transverse axes of the vehicle. The second opening angle can, for example, be at least 90°, at least 120°, or at least 150°.

[0013] Against this background, the reflection sensor requires precise alignment on the vehicle and thus with its surroundings. Currently, the standard practice is to install the reflection sensor on the vehicle and operate it within a defined environment, characterized by environmental parameters, in order to acquire environmental data. Based on this environmental data and parameters, the reflection sensor is calibrated; in particular, any misalignment of the sensor can be detected and corrected. Such calibration is complex and requires a defined environment, which can vary depending on the vehicle model.

[0014] The orientation of the reflector sensor relative to the vehicle's surroundings depends not only on the sensor's alignment with the vehicle, but also on the vehicle's orientation within that environment. For example, the vehicle's orientation changes due to suspension travel. This suspension travel can be influenced by factors such as a load, acceleration, or deceleration. Therefore, the reflector sensor's orientation is significantly affected by factors that are not, and cannot be, considered during its calibration.

[0015] During vehicle operation, calibration is only possible indirectly. For example, the system intends to identify an obstacle in the environmental data that exhibits a defined motion vector relative to the vehicle. This obstacle serves as a reference for calibration. For instance, a stationary obstacle is identified and used as the reference. Based on the motion vector, the system determines how the environmental data describing the obstacle should behave. If the environmental data actually captured by the reflection sensor deviates from this, a fault or misalignment of the reflection sensor is detected. In this case, the environmental data provided by the reflection sensor is no longer evaluated and therefore, for example, no longer used to control the vehicle's operation.

[0016] However, this approach is computationally intensive and does not allow for predictive calibration of the reflection sensor, i.e., calibration of the reflection sensor before the environmental data is acquired, or calibration independent of the already acquired environmental data. Therefore, the invention provides that the vehicle's tilt angle is determined independently of the environmental data. This means that the tilt angle is not determined from data provided by the reflection sensor, but rather that the determination of the tilt angle is independent of the reflection sensor and the data it provides. For example, the tilt angle is measured, particularly using a tilt sensor.

[0017] Depending on the determined tilt angle, the reflection sensor is then calibrated. This means that calibration can be performed before the environmental data acquired by the reflection sensor is further processed, particularly by the control unit. Accordingly, the environmental data describes the surroundings with high accuracy immediately after the vehicle is calibrated, without the need for prior evaluation of the environmental data to calibrate the reflection sensor. The environmental data is therefore available with high accuracy very soon after acquisition and can be used without restriction for driving operations, for example, for longitudinal and / or lateral guidance of the vehicle.

[0018] A further development of the invention provides for the use of a LiDAR sensor as a reflection sensor. The LiDAR sensor can also be referred to as a laser scanner, since it typically uses laser light to detect the environment. The LiDAR sensor enables a particularly high resolution of the environmental data and, accordingly, a particularly accurate representation of the environment in the environmental data.

[0019] A further development of the invention provides that the calibration of the reflection sensor is carried out by mechanically pivoting the reflection sensor and / or by correcting the environmental data. Basically, two different procedures for calibrating the reflection sensor are available, which can be carried out individually or in combination. In a first variant, the calibration of the reflection sensor is performed by mechanically pivoting the reflection sensor.

[0020] For this purpose, the sensor device has an actuator, for example an electric, pneumatic, or hydraulic actuator, by means of which the reflection sensor can be pivoted, namely depending on the determined tilt angle. The pivoting of the reflection sensor using the actuator preferably takes place before the environmental data is acquired, so that the environmental data subsequently acquired using the reflection sensor is immediately adjusted and no longer requires correction.

[0021] According to a second variant, the environmental data is corrected depending on the determined tilt angle after it has been acquired using the reflection sensor. This means that the already acquired environmental data is processed using the tilt angle, specifically in such a way that the tilt angle is taken into account.

[0022] Preferably, the calibration of the reflection sensor is achieved both by mechanically pivoting the reflection sensor and by correcting the environmental data, at least temporarily. For example, it is possible to filter the determined tilt angle and compensate for lower-frequency changes in the tilt angle caused by mechanically pivoting the reflection sensor, and for higher-frequency changes in the tilt angle caused by correcting the environmental data. Thus, for example, the reflection sensor is mechanically pivoted depending on the low-pass filtered tilt angle, while the correction of the environmental data is carried out depending on the high-pass filtered tilt angle. The described measures, either individually or in combination, achieve a particularly high accuracy of the environmental data.

[0023] A further development of the invention provides that the tilt angle is measured by means of a tilt sensor, in particular by means of a tilt sensor integrated into the sensor device, or that a tilt angle provided by a driver assistance system is used as the tilt angle. It is therefore possible to measure the tilt angle directly, namely using the tilt sensor. This is, for example, a component of the sensor device or the reflection sensor itself.

[0024] Alternatively, the tilt sensor is part of the driver assistance system, and in this case, the tilt angle measured by the tilt sensor is provided to the sensor device by the driver assistance system, specifically transmitted to it. Alternatively, the tilt angle is determined indirectly by the driver assistance system, for example, based on a measurement value different from the tilt angle. Driver assistance systems include, for example, an anti-lock braking system, a headlight range control system, an active suspension / damping system, or an active roll stabilization system. These systems also require the tilt angle for their intended function. At least one of the aforementioned systems is usually already installed in the vehicle, so the tilt angle is already available and can be used to calibrate the reflection sensor and thus increase the accuracy of the environmental data.

[0025] A further development of the invention provides that the tilt angle is a pitch angle and / or a roll angle and / or a yaw angle, particularly relative to a direction of movement of the motor vehicle. For example, only one of the aforementioned angles is used as the tilt angle to perform the calibration. However, it is particularly preferred that the calibration is performed using several or all of the aforementioned angles, in particular the pitch angle and either the roll angle or the yaw angle, or both the roll angle and the yaw angle.

[0026] The pitch angle describes the rotational position of the vehicle relative to a transverse axis, the roll angle a rotational position relative to a longitudinal axis, and the yaw angle a rotational position relative to a vertical axis. For example, the longitudinal axis corresponds to the longitudinal axis of the vehicle, the transverse axis to the transverse axis of the vehicle, and the vertical axis to the vertical axis of the vehicle. However, it is also possible for the longitudinal axis, the transverse axis, and the vertical axis to be aligned with the direction of travel of the vehicle, such that the vertical axis runs parallel to the direction of travel and the transverse axis is perpendicular to it.

[0027] The tilt angle(s) are therefore determined in particular relative to the direction of travel or the surface of the vehicle, and thus describe, for example, a deviation of the longitudinal axis of the vehicle from its main direction of travel. The roll angle preferably describes a deviation from an imaginary plane that runs parallel to the surface on which the vehicle is located. The use of one or more of the aforementioned angles enables the calibration of the reflection sensor with high accuracy.

[0028] A further development of the invention provides that the tilt angle is determined at different times, wherein the tilt angle is stored at a first time point after its determination, and the stored tilt angle is used to calibrate the reflection sensor until the second time point. For example, it is provided that the environmental data is acquired using the reflection sensor with a shorter cycle time or a higher frequency than the tilt angle. While the tilt angle is only determined at the different times point in time, the environmental data is also acquired by the reflection sensor between these times point in time.To ensure reliable calibration of the reflection sensor, the tilt angle measured and stored at the first time point is used for calibration until the tilt angle is measured again at the second time point. The tilt angle, once measured, is therefore used until it is measured again. This results in particularly high accuracy when calibrating the reflection sensor.

[0029] A further development of the invention provides that the calibration of the reflection sensor is carried out taking into account a rotation axis associated with the tilt angle. A specific rotation axis is assigned to the tilt angle, around which a rotational position of the vehicle corresponding to the tilt angle is assumed, particularly with respect to the ground. If several tilt angles are used, each tilt angle is assigned its own rotation axis, with the rotation axes preferably being perpendicular to each other. For example, the reflection sensor or its field of view is arranged centrally with respect to an imaginary plane that completely encompasses at least two of the rotation axes.

[0030] For example, a first axis of rotation runs parallel to the longitudinal axis of the vehicle, a second axis parallel to the transverse axis, and a third axis parallel to the vertical axis. In particular, the reflection sensor is positioned centrally with respect to an imaginary plane that completely encompasses the first and third axes of rotation. The axis of rotation, or one of the axes, passes, for example, through the wheel contact points of the wheels on a wheel axle, especially a rear or front axle of the vehicle. This achieves particularly high accuracy when calibrating the reflection sensor.

[0031] A further development of the invention provides that, in addition to the tilt angle, a further tilt angle is determined, and the calibration of the reflection sensor is performed as a function of both the determined tilt angle and the further tilt angle. Thus, when calibrating the reflection sensor, not only the tilt angle is taken into account, but also the further tilt angle or several further tilt angles. In particular, two or more of the following angles are used to calibrate the reflection sensor: pitch angle, roll angle, and yaw angle. Overall, this again achieves the high accuracy required for calibrating the reflection sensor.

[0032] The invention further relates to a sensor device for a motor vehicle, in particular for carrying out the method as described in this description, wherein the sensor device has at least one reflection sensor which is designed and configured to at least temporarily acquire environmental data describing the surroundings of the motor vehicle. The sensor device is designed and configured to determine an inclination angle of the motor vehicle independently of the environmental data and to calibrate the reflection sensor depending on the determined inclination angle.

[0033] The advantages of such a sensor design and procedure have already been mentioned. Both the sensor design and the method for operating it can be further developed as described in this document, and reference is made to those details.

[0034] Furthermore, the invention relates to a computer program product comprising commands that cause the sensor device to execute the described method as described herein. For the advantages and possible advantageous embodiments, reference is made to the description in its entirety.

[0035] The features and combinations of features described in the description, in particular those described in the following figure description and / or shown in the figures, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention. Thus, embodiments that are not explicitly shown or explained in the description and / or the figures, but which emerge from or can be derived from the explained embodiments, are also to be considered as encompassed by the invention.

[0036] The invention is explained in more detail below with reference to the initial examples shown in the drawing, without limiting the invention. The drawing shows: Fig. 1. A schematic representation of a motor vehicle with a sensor device in different views, as well as Fig. 2 a side view of the motor vehicle and of the surroundings of the motor vehicle at a non-zero tilt angle of the motor vehicle.

[0037] The Fig. Figure 1 shows a schematic representation of a motor vehicle 1 in different views: from the front (top left), from the side (top right), and from above (bottom). The motor vehicle has a reflector sensor 2, which is indicated in each of the views. Also indicated in the side and top views is a viewing area 3 of the reflector sensor 2. A pivot point 4 of the motor vehicle 1 is also indicated, at which three axes of rotation 5, 6, and 7 of the motor vehicle 1 intersect. The axis of rotation 5 runs parallel to a longitudinal axis of the motor vehicle, the axis of rotation 6 parallel to a transverse axis of the motor vehicle, and the axis of rotation 7 parallel to a vertical axis of the motor vehicle 1.

[0038] It is evident that the pivot point 4 is located at a distance from the reflection sensor 2, i.e., both in the direction of the axis of rotation 5 and in the direction of the axes of rotation 6 and 7. In particular, the reflection sensor 2 is arranged with respect to the pivot point 4 as follows: in the direction of the axis of rotation 5, at a distance from an imaginary plane that completely encompasses the axes of rotation 6 and 7; in the direction of the axis of rotation 6, centered on an imaginary plane that completely encompasses the axes of rotation 5 and 7; and in the direction of the axis of rotation 7, at a distance from an imaginary plane that completely encompasses the axes of rotation 5 and 6.

[0039] Using the reflection sensor 2, which is preferably designed as a LiDAR sensor, the environment 8 of the vehicle 1 is periodically detected and converted into environmental data, which is then used, for example, to control the operation of the vehicle 1. To improve the accuracy of the environmental data, the reflection sensor 2 is calibrated using a tilt angle of the vehicle 1 about at least one of the axes of rotation 5, 6 and 7.

[0040] The Fig.Figure 2 shows a schematic side view of the vehicle 1 at a specific tilt angle about the axis of rotation 6. An obstacle 9, detected by the reflection sensor, is located in the surrounding area 8. However, due to the tilt angle, the obstacle 9 is not depicted in its actual position in the surrounding area data, which is shown with a thinner line. Therefore, the surrounding area data is adjusted using the tilt angle to correct the position of the obstacle 9 from its position detected due to the tilt angle towards its actual position. This significantly increases the accuracy of the surrounding area data, allowing the vehicle 1 to operate reliably even at a non-zero tilt angle about one or more of the axes of rotation 5, 6, and 7. REFERENCE MARK LIST: 1 motor vehicle 2 reflection sensors 3 Viewing area 4 pivot point 5 axis of rotation 6 axis of rotation 7 axis of rotation 8 Environment 9th obstacle QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2021 105 823 A1

[0002] EP 4 283 332 A1

[0003]

Claims

[1] Method for operating a sensor device for a motor vehicle (1), wherein the sensor device has at least one reflection sensor (2) by means of which environmental data describing an environment (8) of the motor vehicle (1) are recorded at least temporarily, characterized by , that an inclination angle of the motor vehicle (1) is determined independently of the environmental data and that the reflection sensor (2) is calibrated depending on the determined inclination angle. [2] Method according to claim 1, characterized by , that a LiDAR sensor is used as the reflection sensor (2). [3] Method according to any one of the preceding claims, characterized by , that the calibration of the reflection sensor (2) is carried out by mechanically swiveling the reflection sensor (2) and / or by correcting the environmental data. [4] Method according to any one of the preceding claims, characterized by, that the tilt angle is measured by means of a tilt sensor, and / or that the tilt angle is an tilt angle provided by a driver assistance system. [5] Method according to any one of the preceding claims, characterized by , that the tilt angle is a pitch angle and / or a roll angle and / or a yaw angle. [6] Method according to any one of the preceding claims, characterized by , that the inclination angle is determined at different times, wherein the inclination angle is stored after its determination at a first of the times and the stored inclination angle is used to calibrate the reflection sensor (2) until the second time. [7] Method according to any one of the preceding claims, characterized by , that the calibration of the reflection sensor (2) is carried out taking into account a rotation axis (5, 6, 7) associated with the tilt angle. [8] Method according to any one of the preceding claims, characterized by , that in addition to the tilt angle, a further tilt angle is determined and the calibration of the reflection sensor (2) is carried out depending on both the determined tilt angle and the further tilt angle determined. [9] Sensor device for a motor vehicle (1), in particular for carrying out the method according to one or more of the preceding claims, wherein the sensor device has at least one reflection sensor (2) which is designed and configured to at least temporarily capture environmental data describing an environment (8) of the motor vehicle (1), characterized by , that the sensor device is designed and configured to determine an inclination angle of the motor vehicle (1) independently of the environmental data and to calibrate the reflection sensor (2) depending on the determined inclination angle. [10] Computer program product comprising commands that cause the sensor device according to claim 9 to execute the method according to one or more of claims 1 to 8.

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