Method for operating a radar sensor

Abstract

The present invention relates to a method for operating at least one radar sensor (3, 4a-4f) for a vehicle (1), wherein objects in the surroundings of the vehicle (1) are detected with the aid of the at least one radar sensor (3, 4a-4f), and objects are also detected while the vehicle (1) is at a standstill or virtually at a standstill by virtue of the bodywork of the vehicle (1) being made to vibrate (1) with the aid of an actuator.

Description

[0001] Method for operating a radar sensor

[0002] The present invention relates to a method for operating a radar sensor for a vehicle or for an assistance system for a vehicle, a corresponding assistance system and a vehicle which has an assistance system according to the invention.

[0003] Technological background

[0004] Modern means of transport such as motor vehicles or motorcycles are increasingly being equipped with driver assistance systems that use sensor systems to monitor the surroundings, recognize traffic situations, and assist the driver, e.g., by issuing a visual or acoustic warning and / or by braking or steering intervention. This can support or even completely take over the driving task (partially or fully automated). For example, the vehicle can perform autonomous emergency braking (AEB, Automatic Emergency Brake) using an emergency brake assist (EBA), perform speed and follow-through control using a time-gap cruise control or adaptive cruise control (ACC), or maintain the vehicle's lane using a steering assistant (Lane Keep Assist).Furthermore, partially or fully automated parking maneuvers are performed using a parking assistant, in which the driver of the vehicle is supported or replaced during parking in a parking space. Such parking assistants or parking assistance systems can initially detect the parking space using environmental sensors and define the final position of the ego vehicle within the parking space (target pose or target position), with the target position of the vehicle usually being centered in the parking space.

[0005] Radar sensors, lidar sensors, camera sensors, or similar sensors are regularly used as sensor systems for environmental detection. Conclusions about the environment can then be drawn from the sensor data acquired by the sensors. Environmental detection using radar sensors is based on the emission of focused electromagnetic waves and their reflection, e.g., by other road users, obstacles on the road, or the buildings along the edge of the road. The detection of pedestrians is often carried out using camera sensors, but radar sensors are also increasingly being used for this purpose. For systems of the type described above, radar sensors are often used in conjunction with sensors using other technologies, such as camera or lidar sensors. Radar sensors have, among other things,The advantage is that they work reliably even in poor weather conditions and, in addition to the distance between objects, can also directly measure their radial relative velocity via the Doppler effect or the solid angle. The transmission frequencies typically used are 24 GHz, 77 GHz, and 79 GHz. Due to the increasing functional scope of such systems, the requirements are constantly increasing, particularly with regard to the maximum detection range. In addition to the environmental detection of motor vehicles for systems of the type described above, the interior monitoring of motor vehicles is now also becoming a focus, e.g., to detect which seats are occupied; frequencies in the 60 GHz range are used for this. Furthermore, radar sensors have the disadvantage that they only deliver inadequate detection results when stationary, which means that particularly during maneuvers at low speeds or when stationary, such as inIn parking situations, camera or ultrasonic sensors are increasingly used to detect objects and distances.

[0006] Printed state of the art

[0007] From DE 10 2018218 606 A1, a Doppler radar sensor device for a vehicle is known which uses the Doppler radar measuring principle. A radar system based on the Doppler radar measuring principle uses the Doppler effect to determine the approach speed between an obstacle and a vehicle. The resulting Doppler effect means that when the distance between the vehicle and the obstacle changes, a frequency change occurs between the transmitted radar signal and the reflected or received radar signal. This frequency change can be used to determine the approach speed between the obstacle and the vehicle. According to DE 102018218606 A1, it has already been recognized that the Doppler radar measuring principle often reaches its limits when static orstationary obstacles in the vicinity of a vehicle are to be detected, because the stationary obstacle would only be detected if there is a relative movement between the vehicle and the obstacle. However, since the obstacle itself is not moving, the vehicle must move, which makes little sense in some applications. The Doppler radar sensor device comprises an antenna unit for transmitting and / or receiving a radar signal and an actuator unit to which the antenna unit is at least partially attached. The actuator unit is designed to move the antenna unit relative to a vehicle element, in particular the vehicle door, on which the antenna unit is arranged, at least during the transmission and / or reception of the radar signal.By moving the antenna unit relative to the vehicle element, a Doppler effect is created between the antenna unit and the static obstacle, without having to move the vehicle itself in order to also detect static objects or obstacles in the vicinity of the vehicle.

[0008] The actuator unit has a mechanical drive for moving the antenna unit, which can be, for example, a linear drive, a vibration motor, or even a vehicle's loudspeaker membrane driven by another actuator.

[0009] The disadvantage, however, is that modern radar sensors are usually permanently installed on the vehicle for adjustment and calibration. Vibration or

[0010] Movement of the transmitting and / or receiving antenna of the radar sensor by means of an actuator relative to the stationary vehicle can result in the adjustment of the sensor changing and thus requiring frequent readjustment, which can significantly increase maintenance costs.

[0011] Object of the present invention

[0012] Based on the prior art, the object of the present invention is to provide a method for a generic sensor system or assistance system comprising at least one radar sensor, in which objects or object surfaces (e.g. other vehicles) are reliably detected by means of a radar sensor even when the vehicle is stationary and the maintenance effort is reduced.

[0013] Solution to the task

[0014] The above object is achieved by the entire teaching of claim 1 and the subordinate claims. Advantageous embodiments of the invention are claimed in the subclaims.

[0015] In the method according to the invention for operating at least one radar sensor, preferably a plurality of radar sensors, for a vehicle, objects in the vicinity of the vehicle are detected using the at least one radar sensor, wherein the object detection also takes place while the vehicle is stationary or almost stationary by causing the body and / or chassis of the vehicle to vibrate using an actuator. According to the invention, when stationary, the vehicle does not move its wheels or only moves them insignificantly (almost at a standstill), so that no noticeable movement of the vehicle occurs. However, the body of the vehicle or the chassis of the vehicle does move, causing the vehicle to vibrate (slightly). This advantageously generates a vibration, whereby objects can be reliably detected with the radar sensor even when stationary.However, the installation position of the radar sensor or its antennas always remains the same (relative to the vehicle), so that this position is not altered by the method according to the invention, since not only the radar sensor or its transmitting and receiving elements are set into vibration, but the entire vehicle body. This significantly reduces maintenance effort.

[0016] Preferably, the actuator provided is a steering system of the vehicle and / or a suspension system of the vehicle and / or a chassis of the vehicle and / or a vibration unit, in particular arranged on the vehicle body, and / or an engine control system of the vehicle. For example, a hydraulic chassis height adjustment can be provided, by means of which the vehicle body can be moved up and down, causing the vehicle body or the vehicle to vibrate. Furthermore, a combination of different actuators can also be provided.

[0017] Advantageously, the connected radar sensor(s) uses the non-zero Doppler mode to create a radar image from the resulting (much) higher number of detections. For further improvement, a modulation scheme specifically designed for standstill (improved Doppler resolution) can further increase the number of detections.

[0018] The assistance system can expediently carry out a driving function, in particular a parking function, semi-autonomously or fully autonomously, wherein the driving function is carried out on the basis of sensor data from the at least one radar sensor and its object detection. For example, a control device, in particular a central one, can be designed to access sensors and actuators and carry out a parking function, wherein the surrounding objects are detected by the radar sensor(s) and the vehicle is controlled by commands from the control device to the actuators of the vehicle, in particular to the engine, brakes and steering, such that the vehicle carries out a parking maneuver. Likewise, the vibration can be controlled by the actuator via the control device. The distance and / or solid angle (e.g. elevation orElevation angle) to the detected objects when the vehicle is stationary or almost stationary.

[0019] In addition or subordinately, the present invention also claims an assistance system (or sensor system) for a vehicle comprising a body and / or a chassis. The assistance system is preferably operated using a method according to the invention and has a control device for controlling the assistance system, wherein the control device can access sensors and actuators of the vehicle for this purpose. Furthermore, at least one radar sensor, preferably a plurality of radar sensors, which enable complete coverage (entire room, possibly ceiling or the like) of the area around the vehicle is provided as a sensor, wherein objects in the area around the vehicle are detected using the radar sensor or radar sensors. According to the invention, object detection also takes place when the vehicle is stationary or almost stationary by causing the body of the vehicle to vibrate.

[0020] The actuator that causes the vehicle to vibrate can be, for example, a steering system of the vehicle and / or a suspension system of the vehicle and / or a chassis of the vehicle and / or a vibration unit, particularly arranged on the vehicle body, and / or an engine control system of the vehicle. For example, the vibration of the drive motor can also be used when it is started or is running at high idle speed. Advantageously, a turbine vibrator, a ball vibrator, a roller vibrator, a vibrator with an unbalanced motor, or the like can be provided as the vibration unit.

[0021] Preferably, the control device is designed to carry out a driving function, in particular a parking function, based on sensor data from the at least one radar sensor and its object detection.

[0022] Furthermore, the present invention comprises a vehicle comprising a body and / or a chassis having an assistance system according to the invention.

[0023] Description of the invention based on exemplary embodiments

[0024] The invention is described in more detail below using expedient embodiments. Figure 1 shows a simplified schematic representation of an embodiment of a vehicle according to the invention;

[0025] Fig. 2 shows a simplified representation of a parking situation in which a vehicle according to the invention is parked in a parking space between two other vehicles;

[0026] Fig. 3 is a simplified representation of the radar detections of the vehicle from Fig. 2 at standstill, as well as

[0027] Fig. 4 is a simplified representation of the radar detections of the vehicle from Fig. 2 at a standstill when the body is made to vibrate using a method according to the invention.

[0028] Reference numeral 1 in Fig. 1 denotes a vehicle which has a control device 2 (ECU, Electronic Control Unit or ADCU, Assisted and Automated Driving Control Unit) as well as sensors for detecting the environment (front radar sensor 3, radar sensors 4a-4g, lidar sensor 8 and camera 9) and various actuators (steering 5, engine 6, brake 7). The vehicle 1 can be controlled in a (partially) automated manner in that the control device 2 can access the actuators and the sensors or their sensor data. In the area of ​​assisted or (partially) automated driving, the sensor data can be used for environmental and object recognition, so that various assistants or assistance functions, such as distance control (ACC, Adaptive Cruise Control), emergency braking assistant (EBA, Electronic Brake Assist), lane keeping control or a lane keeping assistant (LKA, Lane Keep Assist), parking assistant, traffic jam assistant or the like, can be controlled via the control device 2 orthe algorithm stored there. Furthermore, the radar sensors 3 or 4a-4g are radar sensors that are operated using a method according to the invention. Furthermore, a front radar with a range of, for example, more than 150 m or more than 200 m is provided as radar sensor 3. Furthermore, the radar sensors 4a-4g are radars with ranges of preferably up to 100 m, which enable an all-round view (360° view) around the vehicle 1. The vehicle 1 has an assistance system (or sensor system) according to the invention, which includes, among other things, the control device 2 for controlling the assistance system; for this purpose, the control device can access sensors and actuators of the vehicle. In the vehicle 1 or the assistance system of the vehicle 1, the radar sensors 3, 4a-4g are also used for parking functions or a parking assistant.For this purpose, the radar sensors 3, 4a-4g must be designed such that they can detect objects in the immediate vicinity of the vehicle 1 even when stationary. Object detection also occurs while the vehicle is stationary or almost stationary, by causing the body of the vehicle 1 to vibrate using an actuator. When stationary, the vehicle 1 does not move its wheels or only moves them slightly, so that no noticeable movement of the vehicle occurs. This also makes it practical to determine the distance to the detected objects when the vehicle 1 is stationary or almost stationary.

[0029] Fig. 2 shows a parking situation in which the vehicle 1 according to the invention is parked in a parking space between two other vehicles 10, 11. The vehicle 1 has an assistance system according to the invention, wherein in Fig. 2, for the sake of clarity, only two of the radar sensors (radar sensor 4c and radar sensor 4d) and their detection ranges are shown. The detection ranges of the radar sensors are shown in Fig. 2 with a very short range, but the actual range can be much greater (for example, up to 100 m). In order to detect the vehicles 10, 11 even when the vehicle 1 is stationary, the body of the vehicle 1 is set in motion so that the vehicle 1 is caused to vibrate (slightly). This vibration enables the radar sensors to reliably detect the vehicles 10, 11 even when the vehicle is stationary. The movement of the body is controlled by at least one actuator.The steering 5 and / or the engine 6 and / or the brake 7 and / or a suspension of the vehicle 1 and / or the chassis of the vehicle 1 can be provided as the actuator.

[0030] In a practical way, a chassis height adjustment, in particular a hydraulic one, can be provided, by means of which the body of the vehicle 1 can be moved up and down, whereby the body of the vehicle 1 or the vehicle 1 is set into vibration. For this purpose, the height adjustment is used to raise the vehicle 1 by a few millimeters to centimeters and then lower it again at very short intervals. In a practical way, this can generate a vibration (which can be very strong, depending on the requirements) of the body of the vehicle 1. Furthermore, a quick steering movement of the steering 5 can set the body into vibration without the vehicle 1 moving from its position. Alternatively or additionally, the brake 7 and a targeted actuation of the motor 6 orof the transmission, a kind of jerking of the vehicle can be generated without the vehicle 1 moving away from its position (for this purpose, for example, the brake 7 always remains applied and the engine torque is alternately (strongly) applied and not applied).

[0031] In addition, it can also be provided, for example, that the vibration of the

[0032] drive motor is used when it is started or is operated vigorously at idle, whereby the body of the vehicle 1 vibrates. Alternatively or additionally, a separate vibration unit can be provided which is arranged on the body of the vehicle 1 and which causes the body of the vehicle 1 to vibrate by vibration. Advantageously, the vibration unit can be a turbine vibrator in which, for example, a turbine driven by compressed air with integrated unbalance rotates, or a ball vibrator in which, for example, a ball moves in a circular path, or a roller vibrator in which, for example, a roller moves in a circular path, or a vibrator with an unbalance motor (e.g. a three-phase asynchronous motor with unbalance elements attached to the motor shaft).

[0033] Fig. 3 shows a simplified representation of the radar detections of vehicle 1 in the parking situation from Fig. 2 at a standstill without a vibrating body. Only a small number of radar detections are recorded here, so that reliable detection of vehicles 10, 11 cannot be guaranteed. In contrast, Fig. 4 shows the radar detections of vehicle 1 at a standstill when the body is caused to vibrate using a method according to the invention. An increase in radar detections compared to Fig. 3 is clearly visible, so that detection of vehicles 10, 11 is guaranteed even when vehicle 1 is at a standstill.

[0034] In summary, the assistance system of vehicle 1 can thus perform a driving function or parking function, semi-autonomously or fully autonomously, for example, by the vehicle 1 in Fig. 2 exiting or parking into the parking space. The driving function can be performed based on sensor data from radar sensors 3, 4a-4g and the associated object detection. For example, the vehicles 10, 11 are detected by radars 4c, 4d, and the vehicle 1 is controlled by commands from the control device 2 to the actuators of the vehicle 1, in particular the engine 6, brake 7, and steering 5, such that the vehicle 1 performs a parking maneuver. The method according to the invention also enables the parking function of the vehicle 1 to be performed solely using the radar sensors 3, 4a-4g. Additional ultrasonic sensors or cameras are not required for this purpose.The connected radar sensors advantageously use the non-zero Doppler mode to create a radar image (e.g., a two-dimensional (2D) radar image using SAR or synthetic aperture radar) from the resulting much higher number of detections. LIST OF REFERENCE SYMBOLS: 1 Vehicle.

[0035] 2 Control device

[0036] 3 radar sensor

[0037] 4a-4g radar sensor

[0038] 5 Steering 6 Engine

[0039] 7 Brake

[0040] 8 Lidar sensor

[0041] 9 Camera

[0042] 10 Vehicle 11 Vehicle

Claims

PATENT CLAIMS 1. Method for operating at least one radar sensor (3, 4a-4f) for a vehicle (1), wherein objects in the surroundings of the vehicle (1) are detected by means of the at least one radar sensor (3, 4a-4f), and the object detection also takes place while the vehicle (1) is at a standstill or almost at a standstill by causing the body and / or the chassis of the vehicle (1) to vibrate (1) by means of an actuator.

2. Method according to claim 1, characterized in that a steering system of the vehicle (1) and / or a suspension system of the vehicle (1) and / or a chassis of the vehicle (1) and / or a vibration unit, in particular arranged on the body of the vehicle, and / or an engine control system of the vehicle (1) is provided as the actuator.

3. Method according to claim 1 or 2, characterized in that the radar sensor (3, 4a-4f) operates in non-zero Doppler mode in order to create a radar image from the resulting detections.

4. Method according to one of the preceding claims, characterized in that the assistance system carries out a driving function, in particular a parking function, wherein the driving function is carried out on the basis of sensor data of the at least one radar sensor (3, 4a-4f) and its object recognition.

5. Method according to one of the preceding claims, characterized in that the distance and / or solid angle to the detected objects is determined on the basis of the sensor data of the at least one radar sensor (3, 4a-4f) when the vehicle is at a standstill or almost at a standstill.

6. Assistance system for a vehicle (1), which is operated in particular using a method according to one of the preceding claims, comprising a control device (2) for controlling the assistance system, wherein the control device can access sensors and actuators of the vehicle (1) for this purpose, and at least one radar sensor (3, 4a-4f) is provided as a sensor, wherein objects in the surroundings of the vehicle (1) are detected using the at least one radar sensor (3, 4a-4f), wherein the object detection also takes place when the vehicle (1) is at a standstill or almost at a standstill by causing the body and / or the chassis of the vehicle (1) to vibrate.

7. Assistance system according to claim 6, characterized in that a steering of the vehicle (1) and / or a suspension of the vehicle (1) and / or a chassis of the vehicle (1) and / or a vibration unit, in particular arranged on the body of the vehicle, and / or an engine control of the vehicle (1) is provided as the actuator.

8. Assistance system according to claim 7, characterized in that a turbine vibrator or a ball vibrator or a roller vibrator or a vibrator with an unbalanced motor is provided as the vibration unit.

9. Assistance system according to one of claims 6-8, characterized in that the control device (2) is designed to carry out a driving function, in particular a parking function, based on sensor data of the at least one radar sensor (3, 4a-4f) and its object recognition.

10. Vehicle comprising an assistance system according to one of claims 6-9.

Images