阅读说明：本技术 用于操作监测机动车辆下方的地面区域的机动车辆的超声波传感器装置的方法、超声波传感器装置、驾驶员辅助系统及机动车辆 (Method for operating an ultrasonic sensor device of a motor vehicle for monitoring a ground area underneath the motor vehicle, ultrasonic sensor device, driver assistance system and motor vehicle ) 是由 L.考蒂洛 J.施雷普弗 M.西姆钦 于 2018-05-28 设计创作，主要内容包括：本发明涉及一种用于操作机动车辆(1)的超声波传感器装置(3)的方法,其中超声波信号被传输到机动车辆(1)下方的地面区域(5)中并且从地面区域(5)接收超声波信号,并且控制器(10)用于基于传输的和/或接收的超声波信号来检测地面区域(5)中的物体(6),其中使用超声波传感器装置(3)的第一超声波传感器(4a)来传输超声波信号,并且使用超声波传感器装置(3)的第二超声波传感器(4b)接收由第一超声波传感器(4a)传输并在地面区域(5)中的路面(9)反射的超声波信号,并且控制器(10)用于基于由第二超声波传感器(4b)接收的超声波信号的分量来检测物体(6)。(The invention relates to a method for operating an ultrasonic sensor device (3) of a motor vehicle (1), wherein the ultrasonic signal is transmitted into a ground area (5) below the motor vehicle (1) and the ultrasonic signal is received from the ground area (5), and a controller (10) for detecting objects (6) in the ground area (5) based on the transmitted and/or received ultrasonic signals, wherein a first ultrasonic sensor (4a) of the ultrasonic sensor device (3) is used to transmit ultrasonic signals, and using a second ultrasonic sensor (4b) of the ultrasonic sensor device (3) to receive ultrasonic signals transmitted by the first ultrasonic sensor (4a) and reflected by a road surface (9) in the ground area (5), and the controller (10) is configured to detect the object (6) based on a component of the ultrasonic signal received by the second ultrasonic sensor (4 b).)

1. A method for operating an ultrasonic sensor device (3) of a motor vehicle (1), by means of which ultrasonic signals are transmitted to and received from a ground area (5) beneath the motor vehicle (1), and objects (6) in the ground area (5) are detected by means of a control unit (10) on the basis of the transmitted and/or received ultrasonic signals,

it is characterized in that the preparation method is characterized in that,

the ultrasonic signal is emitted by a first ultrasonic sensor (4a) of the ultrasonic sensor device (3) and the ultrasonic signal emitted by the first ultrasonic sensor (4a) and reflected by a road surface (9) in the ground area (5) is received by a second ultrasonic sensor (4b) of the ultrasonic sensor device (3), and the object (6) is detected by the control unit (10) on the basis of the proportion of the ultrasonic signal received by the second ultrasonic sensor (4 b).

2. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

when the motor vehicle (1) is stopped, the object (6) is detected on the basis of the proportion of the ultrasonic signal received by the second ultrasonic sensor (4 b).

3. The method according to claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

after the motor vehicle (1) has stopped, the proportion of the ultrasonic signal received by the second ultrasonic sensor (4b) is stored and at a later time the proportion of the ultrasonic signal received by the second ultrasonic sensor (4b) is determined again and compared with the stored proportion.

4. The method of claim 3, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

the proportion of the ultrasonic signal received after stopping the motor vehicle (1) is periodically determined and compared with a stored proportion.

5. The method according to any of the preceding claims,

the intensity of the ultrasonic signal received by the second ultrasonic sensor (4b) is determined after stopping the motor vehicle (1) and compared with a predetermined reference intensity to detect the object (6).

6. The method according to any of the preceding claims,

the first ultrasonic sensor (4a) and/or the second ultrasonic sensor (4b) are controlled at predetermined times to clean the respective membranes of the ultrasonic sensors (4a, 4 b).

7. An ultrasonic sensor device (3) for a motor vehicle (1) having at least one first ultrasonic sensor (4a), at least one second ultrasonic sensor (4b) and a control unit (10), wherein the ultrasonic sensor device (3) is designed to carry out the method according to any one of the preceding claims.

8. The ultrasonic sensor device (3) according to claim 7,

it is characterized in that the preparation method is characterized in that,

the ultrasonic sensor device (3) comprises at least four ultrasonic sensors (4, 4a, 4b), in particular at least ten ultrasonic sensors (4, 4a, 4 b).

9. The ultrasonic sensor device (3) according to claim 7 or 8,

it is characterized in that the preparation method is characterized in that,

the ultrasonic sensor device (3) comprises at least one ambient ultrasonic sensor (18) for detecting a surrounding area (19) of the motor vehicle (1), wherein the ultrasonic sensor device (3) comprises a switching device (20) for connecting the at least one first ultrasonic sensor (4a) and the at least one second ultrasonic sensor (4b) to the control unit (10) or for connecting the at least one ambient ultrasonic sensor (18) to the control unit (10).

10. Driver assistance system (2) for a motor vehicle (1) with an ultrasonic sensor device (3) according to any one of claims 7 to 9, wherein the driver assistance system (2) is designed to issue a warning as a function of an object (6) detected in a ground area (5).

11. A motor vehicle (1) having a driver assistance system according to claim 10.

12. Motor vehicle (1) according to claim 11,

it is characterized in that the preparation method is characterized in that,

at least one first ultrasonic sensor (4a) and/or at least one second ultrasonic sensor (4b) are arranged in a corner region (8) on an underbody (7) of the motor vehicle (1).

13. Motor vehicle (1) according to claim 11 or 12,

it is characterized in that the preparation method is characterized in that,

at least one first ultrasonic sensor (4a) and/or at least one second ultrasonic sensor (4b) is arranged on the underbody (7) of the motor vehicle (1) in the middle of the lateral regions (14), the front region (12) and/or the rear region (13).

14. Motor vehicle (1) according to any of claims 11 to 13,

it is characterized in that the preparation method is characterized in that,

at least one first ultrasonic sensor (4a) and/or at least one second ultrasonic sensor (4b) are arranged on the underbody (7) of the motor vehicle (1) in a region (15) in front of and/or in a region (16) behind one of the wheels (17) of the motor vehicle (1).

15. Motor vehicle (1) according to any of claims 11 to 14,

it is characterized in that the preparation method is characterized in that,

at least one first ultrasonic sensor (4a) and/or at least one second ultrasonic sensor (4b) are arranged on a steering element of a steered wheel (17) of a motor vehicle (1).

Technical Field

The invention relates to a method for operating an ultrasonic sensor device of a motor vehicle, wherein an ultrasonic signal is emitted into a ground area beneath the motor vehicle and the ultrasonic signal is received from the ground area, and objects in the ground area are detected by a control unit on the basis of the emitted and/or received ultrasonic signal. In addition, the invention relates to an ultrasonic sensor device for a motor vehicle. The invention further relates to a driver assistance system having such an ultrasonic sensor device. Finally, the invention relates to a motor vehicle.

Background

In the present case, attention is paid to an ultrasonic sensor device for a motor vehicle. Ultrasonic sensor devices comprising a plurality of ultrasonic sensors are known from the prior art. Such an ultrasonic sensor can be used for monitoring the surrounding area of a motor vehicle. In particular, the respective distance between the motor vehicle and the object in the surrounding area can be determined by means of an ultrasonic sensor. Such an ultrasonic sensor device may be part of a driver assistance system, for example, which assists the driver when parking in and/or driving out of a parking space.

Furthermore, ultrasonic sensor devices are known from the prior art, with which the ground area beneath a motor vehicle can be monitored. In this regard, DE102013001119a1 describes a driver assistance system for assisting a driver in parking and/or driving away a vehicle, wherein the driver assistance system comprises at least one sensor device for detecting a surrounding area of the motor vehicle and a control unit for evaluating a signal of the sensor device. For example, the signal may be used to determine the distance between the ground and the bottom of the vehicle. The sensor device and the control unit are arranged such that the detection area of the sensor device comprises at least one predefinable ground area under the motor vehicle. The sensor means may comprise at least one ultrasonic sensor.

Disclosure of Invention

The object of the present invention is to propose a solution as to how to more reliably monitor the ground area under a motor vehicle with an ultrasonic sensor device of the type described above.

According to the invention, this object is achieved by a method, an ultrasonic sensor device, a driver assistance system and a motor vehicle having the features according to the respective independent claims. Advantageous developments of the invention are the subject matter of the dependent claims.

In an embodiment of the method for operating an ultrasonic sensor device of a motor vehicle, an ultrasonic signal is preferably emitted into a ground area beneath the motor vehicle and received from the ground area. Furthermore, it is preferred that objects in the ground area are detected by the control unit based on the transmitted and/or received ultrasonic signals. Furthermore, it is preferred that the ultrasonic signal is emitted by a first ultrasonic sensor of the ultrasonic sensor device and in particular that the ultrasonic signal emitted by the first ultrasonic sensor and reflected at the road surface in the ground area is received by a second ultrasonic sensor of the ultrasonic sensor device. Further, it is preferable that the object is detected by the control unit based on a ratio of the ultrasonic signal received by the second ultrasonic sensor.

The method according to the invention is used for operating an ultrasonic sensor device of a motor vehicle. In this case, the ultrasonic signal is transmitted into and received from a ground area beneath the motor vehicle. In addition, the control unit detects objects in the ground area based on the transmitted and/or received ultrasonic signals. The ultrasonic signal is emitted by a first ultrasonic sensor of the ultrasonic sensor device, and the ultrasonic signal emitted by the first ultrasonic sensor and reflected by the road surface in the ground area is received by a second ultrasonic sensor of the ultrasonic sensor device. The object is detected by the control unit based on the proportion of the ultrasonic signal received by the second ultrasonic sensor.

The method is used for monitoring a ground area beneath a motor vehicle. The ground area may preferably extend from the road surface on which the motor vehicle is currently located to the underbody of the motor vehicle. Thus, for example, before driving a motor vehicle, it is possible to check whether there are objects in the ground area. The method may be performed with an ultrasonic sensor device. The ultrasonic sensor device comprises at least two ultrasonic sensors. The ultrasonic sensor device comprises at least one first ultrasonic sensor for transmitting ultrasonic signals and at least one second ultrasonic sensor for receiving ultrasonic signals. Preferably, the ultrasonic sensor device comprises a plurality of ultrasonic sensors. The ultrasonic sensor may be designed to emit an ultrasonic signal. Furthermore, the ultrasonic sensors can be designed such that they can receive ultrasonic signals. However, it is preferable that the ultrasonic signal be transmitted and received by the respective ultrasonic sensors. The ultrasonic sensor may comprise a membrane which may be excited to mechanical vibrations by a transducer element, in particular a piezoelectric element. This allows the transmission of ultrasonic signals. In order to receive the ultrasonic signal, the vibrations of the membrane caused by the received ultrasonic signal can be detected by the transducer element and output in the form of a sensor signal. The sensor signal can then be evaluated by the control unit of the ultrasonic sensor device to detect the object.

According to a basic aspect of the present invention, there is now provided transmitting an ultrasonic signal by a first ultrasonic sensor. The first ultrasonic sensor functions as a transmitter and transmits an ultrasonic signal. The ultrasonic signal is transmitted into the ground area toward the road surface by the first ultrasonic sensor. The ultrasonic signal is then reflected at the road surface and/or at the underbody of the motor vehicle and can be received by a further or second ultrasonic sensor. This means that the second ultrasonic sensor serves as a receiver for receiving ultrasonic signals. However, a plurality of first ultrasonic sensors for transmitting ultrasonic signals, respectively, and/or a plurality of second ultrasonic sensors for receiving ultrasonic signals, respectively, may be provided. According to the present invention, there is no provision for determining the distance between the ultrasonic sensor and the road surface. The ultrasonic signal is transmitted by a first ultrasonic sensor and received by a second ultrasonic sensor, wherein the second ultrasonic sensor is at a different location than the first ultrasonic sensor. The proportion of the transmitted ultrasonic signal that can be received by the second ultrasonic sensor is now examined. Therefore, whether and how much the second ultrasonic sensor receives the ultrasonic signal transmitted by the first ultrasonic sensor is measured. If an object is located in the ground area between the first ultrasonic sensor and the second ultrasonic sensor, the transmitted ultrasonic signal is at least partially reflected by the object. As a result, the second ultrasonic sensor receives only a small proportion of the transmitted ultrasonic signal or no part. This makes it easy and reliable to check the ground area for objects.

Preferably, the method may be performed using a plurality of ultrasonic sensors. Since the ultrasonic sensor may preferably both transmit and receive an ultrasonic signal, the ultrasonic sensor may be used as the first ultrasonic sensor or the second ultrasonic sensor. The first ultrasonic sensors for transmitting the respective ultrasonic signals may be controlled simultaneously or continuously in time.

Preferably, the object is detected based on a proportion of the ultrasonic signal received by the second ultrasonic sensor when the motor vehicle is stopped. Once the vehicle has stopped or parked, the first ultrasonic sensor may be used to transmit an ultrasonic signal, and the ultrasonic signal reflected at the road surface may be received by the second ultrasonic sensor. In particular, it is possible to check the presence of objects in the ground area before starting the travel of the motor vehicle. Thus, for example, damage to the motor vehicle can be prevented. If the object is an organism, such as an animal, damage to the organism may be prevented.

Furthermore, it is advantageous if, after stopping the motor vehicle, the proportion of the ultrasonic signal received by the second ultrasonic sensor is stored and, at a later time, the proportion of the ultrasonic signal received by the second ultrasonic sensor is determined again and compared with the stored proportion. If the motor vehicle is operated in a direction towards a parking space to be parked, it can be assumed that no objects are present in the parking space, which would otherwise be detected by the driver and/or by environmental sensors. If the proportion of the ultrasonic signal received by the second ultrasonic sensor is determined immediately after the motor vehicle has stopped, this proportion can be used as a reference for the case in which there is no object in the ground area. At a later time, the proportion of the ultrasonic signal received by the second ultrasonic sensor may be determined again. This can then be compared to the stored ratio. Thus, it is easy to use the comparison to determine whether an object is present in the ground area. In particular, it is provided that the proportion of the ultrasonic signal received by the second ultrasonic sensor is determined before the motor vehicle is started to travel. It can also be provided that the ratio is determined periodically and compared with a stored ratio as soon as the motor vehicle is parked.

According to a further embodiment, the intensity of the ultrasonic signal received by the second ultrasonic sensor is determined after the motor vehicle has stopped and compared with a predetermined reference intensity to detect the object. Before commissioning the ultrasonic sensor device, a plurality of reference measurements may be made. Thus, if there is no object in the ground area, a reference intensity may be determined, which describes the intensity of the ultrasonic signal received by the second ultrasonic sensor. For this purpose, reference measurements can be made for different road surfaces, such as asphalt, gravel and/or grass. As already explained, the ultrasonic sensor device may comprise a plurality of ultrasonic sensors. Different measurements may be performed, wherein at least one ultrasonic sensor is used as a first ultrasonic sensor and at least one ultrasonic sensor is used as a second ultrasonic sensor. At a later time, other ultrasonic sensors may be used as the first and/or second ultrasonic sensors. These variations may be performed on different reference measurements. For example, a digital map may be provided based on these reference measured or stored reference intensities, wherein the digital map describes the intensity of the received ultrasonic signal for the respective ultrasonic sensor in case no object is present in the ground area. A reference intensity describing a predetermined object in the ground area may also be stored. This enables reliable monitoring of the ground area.

According to a further exemplary embodiment, it can be provided that the environmental impact is also taken into account when monitoring the ground area. For example, snow and/or ice may be present on the pavement of the ground area. This layer of snow and/or ice on the road surface causes the reflection characteristics of the ultrasonic signal to change. Depending on the ambient temperature and/or warming of the snow and/or ice due to the heat of the motor vehicle, they may melt, which may change the reflection characteristics over time. This can be taken into account in the measurement. This applies in particular when the motor vehicle is parked for a relatively long time. It may also be the case here that the motor vehicle is parked on a lawn, which changes over time and thus changes the reflection properties. By taking these environmental parameters into account, the ground area can be monitored in a reliable manner.

According to another embodiment, the ultrasonic sensor or the first ultrasonic sensor and the second ultrasonic sensor are controlled at predetermined times to clean the respective membranes of the ultrasonic sensors. As already explained, the ultrasonic sensor may comprise a membrane. Contaminants can accumulate on these membranes during operation of the motor vehicle. It is also possible that ice and/or snow are deposited on the film. This is due in particular to the fact that the ultrasonic sensor is arranged in the region of the underbody of the motor vehicle. The ultrasonic sensor may be controlled at a predetermined time such that the membrane is set to mechanically vibrate or strongly vibrate naturally. Thus, deposits and/or dirt on the membrane may be loosened. Thereby enabling the ultrasonic sensor device to operate reliably.

The ultrasonic sensor device for a motor vehicle according to the invention comprises at least one first ultrasonic sensor, at least one second ultrasonic sensor and a control unit. The ultrasonic sensor device is designed to perform the method according to the invention and its advantageous embodiments.

In particular, it is provided that the ultrasonic sensor device comprises at least two first ultrasonic sensors and/or at least two second ultrasonic sensors. The ultrasonic sensor device may thus comprise at least four ultrasonic sensors. In particular, the ultrasonic sensor device comprises at least ten ultrasonic sensors. These ultrasonic sensors can then be distributed in the region of the underbody of the motor vehicle, so that the ground area can be reliably monitored. The first set of ultrasonic sensors may be used as a first ultrasonic sensor, i.e. as a transmitter, and the second set of ultrasonic sensors may be used as a second ultrasonic sensor, i.e. as a receiver. It may also be the case that a change occurs in respect of which ultrasonic sensor is used as the first or second ultrasonic sensor in successive measurement cycles of the ultrasonic sensor device.

In one embodiment, the ultrasonic sensor device comprises at least one ambient ultrasonic sensor for detecting a surrounding area of the motor vehicle, wherein the ultrasonic sensor device is a switching device for connecting the at least one first ultrasonic sensor and the at least one second ultrasonic sensor to the control unit or for connecting the at least one ambient ultrasonic sensor to the control unit. In particular, the ultrasonic sensor device comprises a plurality of ambient ultrasonic sensors. The ambient ultrasonic sensor may be located on a bumper of the motor vehicle. Sensor signals from the first and second ultrasonic sensors for monitoring the ground area may be evaluated using the control unit. Also, the sensor signal provided by the ambient ultrasound sensor may be evaluated by the control unit. A commonly used control unit comprises a predetermined number of channels for processing the sensor signals. This means that the sensor signals of the ultrasonic sensor and of the ambient ultrasonic sensor cannot be evaluated immediately. This is particularly true where the ultrasonic sensor device includes up to twelve ambient ultrasonic sensors. By means of the switching device, the ultrasonic sensor can be connected to the control unit at a first time to monitor the ground area. The ambient ultrasound sensor may then be connected to the control unit at a second time. This eliminates the need for two separate control units. This may save costs and space.

Provision may be made for the switching device to be controlled as a function of the current operating state of the motor vehicle. The ultrasonic sensor for monitoring the ground or the first ultrasonic sensor and the second ultrasonic sensor may be connected to the control unit when the motor vehicle is stopped. When the motor vehicle is started or is being driven, the ambient ultrasonic sensor may then be activated to monitor the surrounding area. Provision can also be made for a digital environment map to be generated by means of the control unit on the basis of the respectively received sensor signals. The digital environment map may describe a ground area and a surrounding area. It can be provided that the ground area is first analyzed and objects in the ground area are filled in the digital environment map. The switching device can then be switched to an external ultrasonic sensor or an ambient ultrasonic sensor and the surroundings of the vehicle can be analyzed accordingly. Here, objects in the surrounding area may also be captured and input into the digital environment map.

The driver assistance system for a motor vehicle according to the invention comprises an ultrasonic sensor device according to the invention. Preferably, the driver assistance system is designed to issue a warning in dependence on objects detected in the ground area. If an object is detected in the ground area using the ultrasonic sensor device, a warning signal can be issued to the vehicle driver using the driver assistance system. It can also be provided that the driver assistance system prevents the motor vehicle from starting, so that damage to the motor vehicle and/or to the object can be prevented. In particular, if the object is in the ground area, autonomous driving maneuvers may be prevented.

The motor vehicle according to the invention comprises a driver assistance system according to the invention. The motor vehicle is in particular designed as a passenger car. It may also be provided that the motor vehicle is designed as a commercial vehicle.

In this case, provision may be made for at least one first ultrasonic sensor and/or at least one second ultrasonic sensor to be arranged on a region of the underbody of the motor vehicle. The ultrasonic sensor is arranged in particular on the underbody of the motor vehicle. The ultrasonic sensors may be configured such that they may emit ultrasonic signals obliquely towards the road surface and/or they may receive ultrasonic signals reflected from the road surface. The ultrasonic sensor may be located in a corner region of the motor vehicle. This makes it possible, in particular, to transmit ultrasonic signals diagonally along the ground area from the first ultrasonic sensor to the second ultrasonic sensor. Provision can also be made for the ultrasonic sensors to be arranged in the side regions, the front region and/or the rear region. The ultrasonic sensor is arranged in particular in the middle of the lateral, rear and/or front regions. It can also be provided that the ultrasonic sensors are arranged in the respective regions in front of and/or behind the wheel. In this area, there is the greatest risk of injury to animals in the ground area. This reliably prevents the object from being damaged by being rolled over by one of the wheels.

In a further embodiment, the at least one first ultrasonic sensor and/or the at least one second ultrasonic sensor are arranged on a steering element of a steered wheel of the motor vehicle. For example, the steering element may be a wheel carrier. The steering element is connected to a steered wheel of the motor vehicle. The ultrasonic sensors are arranged in particular on the steering element such that they can be moved together with the steering element during a steering intervention. If the steering is now actuated with the motor vehicle stationary, the steering element is moved. This causes the ultrasonic sensor located on the steering element to also move. In this way, the ultrasonic sensor can be rotated. Therefore, the detection range of the ultrasonic sensor can be easily expanded.

The preferred embodiments proposed with reference to the method according to the invention and the advantages thereof apply correspondingly to the ultrasonic sensor device according to the invention, to the driver assistance system according to the invention and to the motor vehicle according to the invention.

Further features of the invention emerge from the claims, the figures and the description of the figures. The features and feature combinations mentioned above in the description and the features and/or feature combinations mentioned individually in the description of the figures can be used not only in the respectively given combination but also in other combinations without leaving the scope of the invention. Therefore, embodiments of the invention that are not explicitly disclosed and explained in the figures but which result from the described embodiments due to individual combinations of features and which can be produced are also to be considered to be comprised and disclosed. Characteristic embodiments and combinations that do not comprise all the features of the initially defined independent claims are also to be regarded as disclosed. Furthermore, embodiments and combinations of features which exceed or deviate from the combinations of features set forth in the reference claims are to be regarded as disclosed, in particular, in view of the foregoing embodiments.

The invention will now be described in more detail on the basis of preferred embodiments and with reference to the accompanying drawings.

Drawings

In the figure:

FIG. 1 shows a motor vehicle including an ultrasonic sensor device for monitoring a ground area beneath the motor vehicle, wherein the ultrasonic sensor device includes two ultrasonic sensors, in accordance with an embodiment of the invention;

FIG. 2 illustrates a motor vehicle having an ultrasonic sensor device including four ultrasonic sensors according to an embodiment;

FIG. 3 shows a motor vehicle having an ultrasonic sensor device according to yet another embodiment, wherein the ultrasonic sensor device includes ten ultrasonic sensors;

fig. 4 shows the motor vehicle according to fig. 3 in a side view;

FIG. 5 illustrates a motor vehicle having an ultrasonic sensor device that also includes a plurality of ambient ultrasonic sensors, according to yet another embodiment; and

fig. 6 shows a schematic view of an ultrasonic sensor device comprising an ultrasonic sensor for monitoring a ground area and an ambient ultrasonic sensor.

In the drawings, identical and functionally identical elements have the same reference numerals.

Detailed Description

Fig. 1 shows a motor vehicle 1 according to an embodiment of the invention from the bottom view. In the present case, the motor vehicle 1 is embodied as a passenger car. The motor vehicle 1 comprises a driver assistance system 2 and an ultrasonic sensor device 3. By means of the ultrasonic sensor device 3, a ground area 5 below the motor vehicle 1 can be monitored. In particular, by means of the ultrasonic sensor device 3, it is possible to check whether an object 6 is present in the ground area 5.

The ultrasonic sensor device 3 comprises at least two ultrasonic sensors 4. In the present embodiment, the ultrasonic sensor device 3 includes two ultrasonic sensors 4. The ultrasonic sensors 4 may each be configured to transmit and receive ultrasonic signals. In the present case, the ultrasonic sensor 4 is arranged on the underbody 7 of the motor vehicle 1. In this embodiment, the ultrasonic sensors 4 are arranged at opposite corner regions 8. One of the ultrasonic sensors 4 serves as a first ultrasonic sensor 4a or a transmitter. The ultrasonic signal is emitted by the first ultrasonic sensor 4 a. The transmitted ultrasonic signal may then be reflected at the road surface 9 and/or underbody 7 of the ground area 5. The other ultrasonic sensor 4 serves as a second ultrasonic sensor 4b or receiver. The ultrasonic signal may be received by the second ultrasonic sensor 4 b.

The ultrasonic sensor device 3 further comprises a control unit 10. A sensor signal describing the received ultrasonic signal may be received from the second ultrasonic sensor 4b by the control unit 10. In the present case, the object 6 is located on the transmission line 11 between the first ultrasonic sensor 4a and the second ultrasonic sensor 4 b. The ultrasonic signal is transmitted from the first ultrasonic sensor 4a to the second ultrasonic sensor 4b along the transmission line 11. Therefore, the ultrasonic signal emitted by the first ultrasonic sensor 4a is reflected at the object 6. Therefore, no ultrasonic signal is received by the second ultrasonic sensor 4 b. By evaluating the sensor signals by means of the control unit 10, it can then be recognized that the object 6 is located in the ground area 5.

Fig. 2 shows a motor vehicle 1 with an ultrasonic sensor device 3 according to a further embodiment. Here, the ultrasonic sensor device 3 includes four ultrasonic sensors 4. One of the ultrasonic sensors 4 is arranged in the middle of the front region 12 of the motor vehicle 1, the other ultrasonic sensor 4 is arranged in the middle of the rear region 132 of the motor vehicle 1, and the remaining two ultrasonic sensors 4 are centered on the respective side regions 14 of the motor vehicle 1. These four ultrasonic sensors can basically be used as a first ultrasonic sensor 4a or transmitter or as a second ultrasonic sensor 4b or receiver. Between the four ultrasonic sensors 4 there are different transmission lines 11 through which ultrasonic signals can be exchanged. Then, based on the ultrasonic signal received by one of the second ultrasonic sensors 4b, it can be identified that the object 6 is located in the ground area 5. Furthermore, known transmission lines 11 can be used to determine where the object 6 is located in the ground area 5.

Fig. 3 shows a motor vehicle 1 with an ultrasonic sensor device 3 according to a further embodiment. Here, the ultrasonic sensor device 3 includes ten ultrasonic sensors 4. One of the ultrasonic sensors 4 is arranged here in the middle of a front region 12 of the motor vehicle 1, and one of the ultrasonic sensors 4 is arranged in the middle of a rear region 13 of the motor vehicle 1. The further ultrasonic sensors 4 are arranged in a region 15 in front of a wheel 17 of the motor vehicle 1 and in a region 16 behind the wheel 17 of the motor vehicle 1. In the present example, two of the ultrasonic sensors 4 are used as the first ultrasonic sensor 4 a. Here, too, some transmission lines 11 between the first ultrasonic sensor 4a and the second ultrasonic sensor 4b are shown by way of example.

By way of example, fig. 4 shows the propagation of an ultrasonic signal emitted by the first ultrasonic sensor 4a and received by the second ultrasonic sensor 4 b. It can be seen that the ultrasonic signal is reflected on the one hand at the road surface 9 and on the other hand at the underbody 7. Thus, the presence of objects 6 in the entire ground area 5 can be monitored.

Fig. 5 shows a motor vehicle 1 with an ultrasonic sensor device 3 according to a further embodiment. Here, the ultrasonic sensor device 3 includes eight ultrasonic sensors 4. Two of the ultrasonic sensors 4 are arranged in a front region 12 of the motor vehicle 1, and two of the ultrasonic sensors 4 are arranged in a rear region 13 of the motor vehicle 1. Furthermore, two ultrasonic sensors 4 are arranged in a region 15 in front of the wheel 17, and two ultrasonic sensors 4 are arranged in a region 16 behind the wheel 17.

Furthermore, the ultrasonic sensor device 3 includes a plurality of ambient ultrasonic sensors 18. With the ambient ultrasonic sensor 18, a surrounding area 19 around the motor vehicle 1 can be detected. In the present case, six ambient ultrasonic sensors 18 are located in the front region 12, and six ambient ultrasonic sensors are arranged in the rear region 13. The ambient ultrasonic sensor 18 may be arranged on a bumper of the motor vehicle 1.

Fig. 6 shows a schematic view of an ultrasonic sensor device 3 according to another embodiment. In the present case, one of the ultrasonic sensors 4 and one of the ambient ultrasonic sensors 18 as well as the control unit 10 are shown by way of example. The ultrasonic sensor device 3 further comprises a switching device 20, which is shown by way of example. By means of the switching means 20, the ultrasonic sensor 4 can be connected to the control unit 10 for data transmission, or the ambient ultrasonic sensor 18 can be connected to the control unit 10 for data transmission. For example, the ground area 5 may be monitored at a first time. For this purpose, the ultrasonic sensor 4 may be connected to a control unit 10. This is done in particular when the motor vehicle 1 is stationary. For example, a digital environment map may be determined, which describes the objects 6 in the ground area 5. Subsequently, the ambient ultrasonic sensor 18 may be connected to the control unit 10. This is done in particular when the motor vehicle 1 is running. Thus, the surrounding area 19 of the motor vehicle 1 can be detected, and the digital environment map of the surrounding area 19 can be updated.

Before starting the drive, it can be checked whether an object is present in the ground area 5. If an object 6 is detected in the ground area 5 by the ultrasonic sensor device 3, a warning can be issued to the driver of the motor vehicle 1 by means of the driver assistance system 2. Provision may also be made for the activation of motor vehicle 1 and/or the deactivation of autonomous driving of motor vehicle 1 to be prevented as long as object 6 is present in ground region 5.