Method and device for operating an ultrasonic sensor of a vehicle

Abstract

The present invention relates to a method for operating an ultrasonic sensor (102) of a vehicle (100), characterized in that a front ultrasonic sensor (102) of the vehicle (100) is used to identify wind noise of the vehicle (100), a rear ultrasonic sensor (102) of the vehicle (100) is used to identify road conditions in the area of ​​the vehicle (100), and a side ultrasonic sensor (102) of the vehicle (100) is used to identify objects in the area of ​​the vehicle (100).

Description

Technical Field

[0001] The invention relates to a method and a device for operating an ultrasonic sensor of a vehicle. Background Art

[0002] The use of ultrasonic sensors makes it possible to detect obstacles in the vehicle's surroundings at lower vehicle speeds. At higher speeds, wind noise and tire noise can make detection difficult. Summary of the invention

[0003] Against this background, a method for operating an ultrasonic sensor of a vehicle, a device for operating an ultrasonic sensor of a vehicle, and finally a corresponding computer program product and a machine-readable storage medium are proposed with the aid of the solution proposed here according to the independent claims. Advantageous developments and improvements of the solution proposed here are derived from the description and are described in the dependent claims.

[0004] Advantages of the present invention

[0005] Embodiments of the present invention can advantageously enable ultrasonic sensors of different orientations of a vehicle to be used for different tasks. Here, the ultrasonic sensors can each be used for a task for which they are particularly suitable.

[0006] A method for operating ultrasonic sensors of a vehicle is proposed, characterized in that a front ultrasonic sensor of the vehicle is used to detect wind noise on the vehicle, a rear ultrasonic sensor of the vehicle is used to detect road conditions in the area of ​​the vehicle, and a side ultrasonic sensor of the vehicle is used to detect objects in the area of ​​the vehicle.

[0007] In particular, it is believed that the concepts related to the embodiments of the present invention are based on the ideas and knowledge described below.

[0008] A vehicle can have ultrasonic sensors that are oriented in different directions. When the ultrasonic sensor is actively operated, it emits ultrasonic pulses into an orientation-dependent detection range. The ultrasonic pulses are partially reflected at objects in the detection range and are received again as echoes at the ultrasonic sensor. The echo has a much lower intensity than the ultrasonic pulse. The distance to the corresponding object can be determined from the propagation time of the ultrasonic pulse and the echo. In addition to the echo, the ultrasonic sensor also detects the ambient noise if it is in the receiving frequency band of the ultrasonic sensor. If the ambient noise is louder than the echo, the ambient noise will prevent the echo from being received.

[0009] During driving, the driving wind caused by the local wind speed, the local wind direction, and the current vehicle speed flows around the vehicle. The driving wind causes noise on the body of the vehicle, which may be called wind noise and can be detected by the ultrasonic sensor. Depending on the vehicle speed, wind speed, and wind direction, the wind noise may be louder than the echo.

[0010] Depending on the vehicle speed, the tires of the vehicle cause a noise when rolling on the roadway, which noise may be referred to as rolling noise and can be detected by the ultrasonic sensor. Depending on the vehicle speed, the rolling noise may be louder than the echo.

[0011] If the road conditions of the road are wet or damp, the tires cause additional noise when rolling, which noise can be called wet hiss, for example, and can be detected by the ultrasonic sensor. Depending on the road conditions and the vehicle speed, the wet hiss can be louder than the echo.

[0012] Regardless of the vehicle speed, other noise sources can generate extraneous noise. Other vehicles, for example, generate wind noise, rolling noise, and wet hiss when the roadway is wet or damp. These extraneous noises can also be detected by ultrasonic sensors.

[0013] Different ambient noises and external noises are superimposed on each other, so that mixed ambient noise is detected at each ultrasonic sensor.

[0014] Different ambient noises have different intensities on ultrasonic sensors with different orientations. Wind noise has high intensity on ultrasonic sensors oriented forward. Rolling noise and wet hiss have high intensity on sensors oriented backward. Extraneous noise from other vehicles has high intensity on ultrasonic sensors oriented laterally.

[0015] In order to identify wind noise and / or to identify road conditions and / or to identify objects, the noise level detected at the ultrasonic sensor can be analyzed. The external noise can be quantified as a numerical value. This numerical value can be called the noise level. Therefore, the noise level indicates the intensity of the ambient noise at the ultrasonic sensor. The noise level has been determined in the ultrasonic sensor and mapped in the received signal of the ultrasonic sensor. By using the noise level, further data processing can be performed with less computing overhead.

[0016] In order to identify an object, the echo detected on the ultrasonic sensor can be analyzed. The object can also be detected actively. The distance to the object can also be determined from the propagation time of the echo signal. In addition, the external noise emitted by the object can be analyzed based on the received noise level.

[0017] By using the wind noise detected on the ultrasonic sensor oriented forward and / or the objects detected on the ultrasonic sensor oriented laterally, the wind noise and / or the objects mapped in the sensor information of the ultrasonic sensor oriented backward can be compensated. By using the wind noise detected on the ultrasonic sensor oriented forward and / or the road conditions detected on the ultrasonic sensor oriented backward, the wind noise and / or the road conditions mapped in the sensor information of the ultrasonic sensor oriented laterally can be compensated. By using the road conditions detected on the ultrasonic sensor oriented backward and / or the objects detected on the ultrasonic sensor oriented laterally, the objects and / or the road conditions mapped in the sensor information of the ultrasonic sensor oriented forward can be compensated. Since different components of the ambient noise are respectively detected particularly well on ultrasonic sensors of different orientations, the components of the ambient noise that are detected less well can be compensated respectively.

[0018] The sensor information of the ultrasonic sensors arranged in pairs symmetrically to the longitudinal axis of the vehicle can be jointly evaluated. The noise of the host vehicle is essentially the same on both sides of the vehicle. If different noises are detected on both sides, it is most likely external noise from external noise sources on the side of the vehicle.

[0019] The sensor information of the ultrasonic sensor arranged on the side of the vehicle can be used to identify other vehicles that are overtaking or being overtaken on the side of the vehicle. The overtaking vehicle and the overtaken vehicle travel at different speeds. As a result, the overtaken vehicle is first identified at the front sensor. The overtaking vehicle is first identified at the rear sensor.

[0020] The method can be implemented, for example, in the form of software or hardware or in the form of a mixture of software and hardware, for example in a control unit.

[0021] The solution proposed here also proposes a device which is designed to carry out, control or implement the steps of a variant of the method proposed here in a corresponding device.

[0022] The device can be an electrical device having at least one computing unit for processing signals or data, at least one storage unit for storing signals or data, and at least one interface and / or a communication interface for reading or outputting data embedded in a communication protocol. The computing unit can be, for example, a signal processor, a so-called system ASIC or a microcontroller, which is used to process sensor signals and output data signals according to the sensor signals. The storage unit can be, for example, a flash memory, an EPROM or a magnetic storage unit. The interface can be configured as a sensor interface for reading sensor signals from a sensor and / or an actuator interface for outputting data signals and / or control signals to an actuator. The communication interface can be configured to read or output data wirelessly and / or wiredly. The interface can also be a software module that coexists on a microcontroller, for example, with other software modules.

[0023] Also advantageous is a computer program product or a computer program having a program code, which can be stored on a machine-readable carrier or a storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used to execute, implement and / or control the steps of the method according to one of the above-described embodiments - in particular when the program product or the program is implemented on a computer or a device.

[0024] It should be noted that some of the possible features and advantages of the present invention are described herein with reference to different embodiments. Those skilled in the art recognize that the features of the methods and devices can be combined, matched or exchanged in an appropriate manner to obtain other embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Embodiments of the present invention are described below with reference to the accompanying drawings, wherein neither the accompanying drawings nor the description should be interpreted as limiting the present invention.

[0026] Figure 1 Illustrations of a vehicle with ultrasonic sensors and devices in different orientations according to one exemplary embodiment are shown.

[0027] The accompanying drawings are schematic only and are not drawn to scale. In the accompanying drawings, the same reference numerals indicate features having the same or similar functions. DETAILED DESCRIPTION

[0028] Figure 1 A diagram of a vehicle 100 with ultrasonic sensors 102 in different orientations and with a device 104 according to one exemplary embodiment is shown. Ultrasonic sensors 102 are arranged distributed over vehicle 100. Ultrasonic sensors 102 are numbered from one to thirteen in a clockwise direction.

[0029] In this case, first ultrasonic sensor 102 is arranged at the left front corner of vehicle 100 and is oriented to the left with respect to vehicle longitudinal axis 106 of vehicle 100. Second ultrasonic sensor 102 is also arranged at the left front corner and is oriented obliquely to the left front with respect to vehicle longitudinal axis 106. Third ultrasonic sensor 102 is likewise arranged at the left front corner and is oriented forward.

[0030] Fourth ultrasonic sensor 102 is arranged symmetrically to third ultrasonic sensor 102 at the right front corner of vehicle 100 with respect to vehicle longitudinal axis 106 and is oriented forward like third ultrasonic sensor 102. Fifth ultrasonic sensor 102 is also arranged symmetrically to second ultrasonic sensor 102 at the right front corner with respect to vehicle longitudinal axis 106 and is oriented obliquely to the right front with respect to vehicle longitudinal axis 106. Sixth ultrasonic sensor 102 is likewise arranged symmetrically to first ultrasonic sensor 102 at the right front corner with respect to vehicle longitudinal axis 106 and is oriented to the right with respect to vehicle longitudinal axis 106.

[0031] The number seven was unassigned.

[0032] Eighth ultrasonic sensor 102 is arranged at the right rear corner of vehicle 100 and is oriented to the right with respect to vehicle longitudinal axis 106. Ninth ultrasonic sensor 102 is also arranged at the right rear corner and is oriented obliquely to the right rear with respect to vehicle longitudinal axis 106. Tenth ultrasonic sensor 102 is likewise arranged at the right rear corner and is oriented rearward.

[0033] Eleventh ultrasonic sensor 102 is arranged symmetrically to tenth ultrasonic sensor 102 at the rear left corner of vehicle 100 with respect to vehicle longitudinal axis 106 and is oriented rearward like tenth ultrasonic sensor 102. Twelfth ultrasonic sensor 102 is also arranged symmetrically to ninth ultrasonic sensor 102 at the rear left corner with respect to vehicle longitudinal axis 106 and is oriented obliquely to the rear left with respect to vehicle longitudinal axis 106. Thirteenth ultrasonic sensor 102 is likewise arranged symmetrically to eighth ultrasonic sensor 102 at the rear left corner with respect to vehicle longitudinal axis 106 and is oriented to the left with respect to vehicle longitudinal axis 106.

[0034] By using the emitted ultrasonic waves, each ultrasonic sensor 102 can perform echolocation of an object in its corresponding detection area 108 and map the distance to the object in the sensor information 110. Alternatively or additionally, each ultrasonic sensor 102 can detect ambient noise and map it in the sensor information 110. Here, the intensity of the ambient noise is respectively mapped in the noise level 112 of the sensor information 110.

[0035] Sensor information 110 of all ultrasonic sensors 102 is read out by device 104 .

[0036] When vehicle 100 is moving slowly, for example when maneuvering, parking or in a traffic jam, echolocation works as expected and little ambient noise is detected. When the ambient noise becomes louder than the echo of the ultrasound, echolocation works only to a limited extent.

[0037] For example, the traveling wind generates wind noise on the body of the vehicle 100, which is detected by the ultrasonic sensor 102. In addition, the tires of the vehicle 100 generate rolling noise, which is also detected by the ultrasonic sensor 102. If the road is wet or damp, the tires additionally generate water noise or wet hissing, which is also detected by the ultrasonic sensor 102. Wind noise, rolling noise and wet hissing are included in the ambient noise together with the external noise of other noise sources. At least the wind noise, rolling noise and water noise become louder as the speed of the vehicle 100 increases.

[0038] In the solution proposed here, the sensor information 110 of the ultrasonic sensor 102 oriented substantially forward is used to detect wind noise. The sensor information 110 of the ultrasonic sensor 102 oriented substantially backward is used to detect water noise and rolling noise. The sensor information 110 of the ultrasonic sensor 102 oriented substantially laterally is used to detect extraneous noise of other noise sources.

[0039] In other words, a method is proposed for sensor selection in the area of ​​detecting moisture on a roadway using ultrasound.

[0040] At present, it is not possible to directly measure the roadway humidity or the millimeter water column indication on the roadway. A wet roadway can be indirectly inferred from different operating states of the vehicle. This can be achieved, for example, by windshield wiper activity or ESP intervention. At present, there is no continuous "measurement" of the roadway state in terms of wetness.

[0041] Ultrasonic sensors are installed near the wheel arches for obstacle detection. A significant problem with obstacle detection during faster driving is the driving noise, which overlaps with the echo from the sensor and thus severely limits the distance measurement in some cases. The more water splashes from the tire onto the wheel arch, the louder the driving noise and the greater the limitation. The noise level reaches the sensor mainly directly via the air, but can also be received indirectly by the sensor via structure-borne noise. These noises can be calculated in the ultrasonic control unit as noise levels or "noises" (interference variables, noise values). The noise level can be output to other control units in the vehicle via the CAN.

[0042] Driving tests have shown that the quality of detecting roadway properties (e.g., moisture) or environmental properties (e.g., detecting other vehicles) is highly dependent on the respective selection of the ultrasonic sensors (USS) involved. Not every sensor position (currently, up to 12 sensors can be installed per vehicle) is equally suitable or even has a negative impact on the respective detection method. Therefore, the appropriate sensor selection plays a very important role in order to be able to draw robust and high-quality conclusions about the moisture on the roadway.

[0043] Ultrasonic sensors can detect fundamentally different properties of the surroundings or roadway. These include object detection, moisture detection on the roadway, and wind detection.

[0044] In the solution proposed here, the wind speed in the longitudinal direction is calculated with the help of the noise level of the front sensor, objects are identified with the help of the noise level of the side sensors, and the humidity on the road is measured with the help of the noise level of the rear sensor. Since the wind and objects also influence the noise level of the rear sensor, the measurement of humidity is corrected with the help of the wind information and the object information.

[0045] The four sensors arranged laterally (numbers 1, 6, 8, 13) are decisive for detecting objects (other road users, such as vehicles, trucks, etc.) Here, the corresponding differential signals of the noise values ​​of the front sensors (numbers 1, 6) and the rear sensors (numbers 13, 8) are evaluated.

[0046] Udiff.1,6[mV]=U1[mV]-U6[mV]

[0047] If Udiff.1,6>threshold, the object is an object that is overtaken by another vehicle on the left side of the vehicle

[0048] If Udiff.1,6<-threshold, the object is the object that exceeds the own vehicle on the right side of the vehicle

[0049] Udiff.13,8 behaves in the same way.

[0050] The temporal behavior of the differential signals Udiff.1,6 and Udiff.13,8 also enables inferences to be drawn about an overtaking or overtaking process. In an overtaking process, first an increase in the differential signal occurs at the front sensors (1, 6) in a vehicle-specific manner on the right side of the direction of travel, and then an increase in the differential signal occurs at the rear sensors (8, 13) in a temporally corresponding manner to the differential speed. In an overtaking process, the opposite occurs and occurs on the left side. In addition, continuous objects (guardrails, walls, etc.) and their positions (distance, left or right) can be inferred from a temporally (longer) constant differential signal.

[0051] Different threshold values ​​are used for different object types (passenger cars, trucks, etc.). Thus, the corresponding object can also be inferred during driving operation and its authenticity can be verified, for example, by means of the object in the radar / lidar / camera environment. For object recognition, in addition to measuring the noise level, the sensors (1, 6, 8, 13) can also actively emit ultrasonic signals throughout a characteristically specific speed range (currently >= 60 km / h) and recognize objects by means of the received echoes, provided that these echoes are not suppressed by an excessively high noise level.

[0052] The four rear sensors (numbers 9, 10, 11, 12) are decisive for detecting the roadway moisture. With this sensor selection, the best measurement results can be obtained for the currently existing roadway moisture. In these sensor positions, for example, wind influences are minimal.

[0053] If no object is detected in the detection area by vehicle-specific object detection, all rear sensors (numbers 9, 10, 11, 12) can be used for moisture detection. The sensors can be operated actively or passively, since noise values ​​can be determined and processed in any case.

[0054] If a continuous object (guardrail, etc.) is detected in the detection area by vehicle-specific object detection (e.g. also by means of radar, camera or lidar), the moisture detection can be stopped. Alternatively, however, all rear sensors (numbers 9, 10, 11, 12) can also be used for moisture detection. However, the sensor values ​​of the rear sensors are then reduced by sensor-specific and possibly object-specific correction values. This compensates for the influence of the object on the sensor-specific noise level.

[0055] If a short-term object (vehicle, etc.) is detected in the detection area by vehicle-specific object recognition, the rear sensors for moisture recognition (numbers 9, 10, 11, 12) are partially deactivated in an object-specific manner. Object groups are formed that have similar influence patterns (curves and strengths) with respect to the noise values ​​of the individual sensors. For each object group, it is defined which sensors for moisture recognition can still contribute to moisture recognition during the influence period.

[0056] During this influence, the calculation of the humidity does not take into account the noise level of all other sensors. For example, in the case of the object type "passenger car", only the two sensors close to the object are deactivated (see also continuous objects). In the case of the object type "truck", on the other hand, all rear sensors are not taken into account, because here, humidity detection cannot currently be performed by ultrasonic sensors.

[0057] Convert the continuous noise value of the sensor raw signal into a sensor-individualized state. Here, each sensor is assigned an index (sensor name):

[0058] i = [1 2 3 4 5 6NaN 8 9 10 11 12 13] because index 7 is not applied.

[0059] The result is output as a state vector:

[0060] Z = [1 2 3 4 5], where the state is interpreted as follows, and intermediate values ​​are allowed:

[0061] 1. Dry

[0062] 2: Moisture

[0063] 3: Wet

[0064] 4: Very humid

[0065] 5: Water skiing risk

[0066] n: sampling point of the state vector (Stützstelle)

[0067] v: speed (correlation)

[0068] t: time (correlation)

[0069] s(i): sensor selection

[0070] s(i).SZ(t): sensor result at time t

[0071] stst noise: support point value of noise value

[0072] tracker noise: The current noise value of the sensor

[0073] It can be calculated as follows:

[0074]

[0075] Based on the results of the individually calculated sensor individualizations, a sensor fusion value is calculated for all sensors by means of a fusion factor. The size of the sensor individualization fusion factor depends on the “object recognition”.

[0076] Examples of different fusion factors k when the roadway is detected as wet or very wet. In this case, the marked sensors are not taken into account in each case.

[0077] k1(i) = [0 0 0 0 0 0 NaN 0 2 4 4 2 0] Object not recognized

[0078] Overtaking object detected (passenger car)

[0079] Overtaking object detected (truck)

[0080] Identify the object being overtaken (passenger car)

[0081] Compute the fused result:

[0082]

[0083] SZ fus(t): Fusion result of humidity identification

[0084] v_tracker noise: current vehicle speed

[0085] The four sensors at the front (2, 3, 4, 5) are decisive for detecting the wind in the longitudinal direction of the vehicle. The following effect is used here: the wind has an increasing influence on the noise level of the individual sensors at the front. This effect can be determined in experimental tests and mapped into corresponding model values. In this case, the vehicle is subjected to driving wind in the longitudinal direction (for example in a wind tunnel). This allows the sensor-specific noise values ​​to be mapped as a function of the wind speed and the following relationship to be formed:

[0086] (1) Vwind [km / h] = Vdriving wind - Vvehicle [km / h]

[0087] (2) Vvehicle = 0 km / h (in the wind tunnel)

[0088] (3) V driving wind [km / h] ~ N sensor [mV] * k [km / h / mV]

[0089] (4) Vwind [km / h] = Nsensor [mV] * k [km / h / mV] - Vvehicle [km / h]

[0090] V: Speed

[0091] N: noise value "noise"

[0092] k: speed-dependent correction factor

[0093] Or in a road test:

[0094] (1) Vwind [km / h] = Vdriving wind - Vvehicle [km / h]

[0095] (2) Vwind = 0 km / h (windless day)

[0096] (3) V driving wind [km / h] = V vehicle [km / h]

[0097] (4) V driving wind [km / h] ~ N sensor [mV] * k [km / h / mV]

[0098] (5) Vwind [km / h] = Nsensor [mV] * k [km / h / mV] - Vvehicle [km / h]

[0099] Since a headwind increases the noise level of the four rear sensors and reduces the mitwind in the same way, the wind speed calculated with the aid of the four front sensors is used to compensate for the noise level of the four rear sensors.

[0100] The concept presented here can be used as a software feature in every passenger car with integrated automatic parking / exit assistance. In principle, the method can be used for all vehicles with ultrasonic sensors. Since only one calculated signal is available on the CAN bus and the driver is warned based on this signal, the minimal conversion can be carried out very cost-effectively on the ultrasonic control unit and HMI by means of software changes.

[0101] Finally, it should be pointed out that terms such as "having", "comprising" etc. do not exclude other elements or steps and the terms "a" or "an" or the indefinite quantifier do not exclude a plurality. Reference signs in the claims shall not be considered as limitations.

Claims

1. A method for operating an ultrasonic sensor (102) of a vehicle (100), characterized in that: A front ultrasonic sensor (102) of the vehicle (100) oriented substantially forward is used to detect wind noise on the vehicle (100), a rear ultrasonic sensor (102) of the vehicle (100) oriented substantially backward is used to detect road conditions in the area of ​​the vehicle (100), and a side ultrasonic sensor (102) of the vehicle (100) oriented substantially laterally is used to detect objects in the area of ​​the vehicle (100), wherein: using the identified wind noise and / or the identified object to compensate for the wind noise and / or the object mapped in the sensor information (110) of the rearward-oriented ultrasonic sensor (102); and / or The identified wind noise and / or the identified road condition are used to compensate for the wind noise and / or the road condition mapped in the sensor information (110) of the laterally oriented ultrasonic sensor (102).

2. The method according to claim 1, wherein a noise level (112) detected at the ultrasonic sensor (102) is evaluated in order to identify the wind noise and / or to identify the road condition and / or to identify the object.

3. The method according to claim 1, wherein the echo detected at the ultrasonic sensor (102) is evaluated for the purpose of identifying the object.

4. The method according to claim 1, wherein sensor information (110) from ultrasonic sensors (102) arranged in pairs symmetrically to a vehicle longitudinal axis (106) of the vehicle (100) is jointly evaluated.

5. The method according to claim 4, wherein sensor information (110) of an ultrasonic sensor (102) arranged on the side of the vehicle is used to identify other vehicles that are overtaking or being overtaken on the side of the vehicle.

6. A device (104), wherein: The device (104) is designed to carry out, implement and / or control a method according to any of the preceding claims in a corresponding apparatus. 7 . A computer program product, which is designed to carry out, implement and / or control the method according to claim 1 .

8. A machine-readable storage medium on which the computer program product according to claim 7 is stored.

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