Method for determining dirt of a first ultrasonic sensor, computer program product, computer-readable storage medium, ultrasonic sensor device and assistance system

Abstract

The invention relates to a method for determining dirt of a first ultrasonic sensor (4) of a motor vehicle (1), wherein a first ultrasonic signal (7) is emitted by the first ultrasonic sensor (4) and a reflected first ultrasonic signal (7) is received by the first ultrasonic sensor (4), and wherein a second ultrasonic signal (9) different from the first ultrasonic signal (7) is emitted into the environment (8) by a second ultrasonic sensor (5) substantially simultaneously with the first ultrasonic signal (7), wherein the second ultrasonic signal (9) is received by the first ultrasonic sensor (4), and the received first ultrasonic signal (7) is compared with the received second ultrasonic signal (9) by an electronic computing device (6), and dirt is determined on the basis of the comparison. The invention also relates to a computer program product, a computer-readable storage medium, an ultrasonic sensor device (3) and an assistance system (2).

Description

Technical Field

[0001] This invention relates to a method for determining contamination of a first ultrasonic sensor in an ultrasonic sensor device for an auxiliary system of a motor vehicle, wherein the first ultrasonic sensor is used to transmit a first ultrasonic signal into the environment of the motor vehicle and to receive a first ultrasonic signal reflected in the environment, and wherein a second ultrasonic sensor of the ultrasonic sensor device is used to transmit a second ultrasonic signal, different from the first ultrasonic signal, into the environment substantially simultaneously with the first ultrasonic signal. Furthermore, this invention relates to a computer program product, a computer-readable storage medium, an ultrasonic sensor device, and an auxiliary system. Background Technology

[0002] Existing technologies have disclosed motor vehicles with driver assistance systems. Increasingly demanding requirements for a range of functions necessitate further development of ultrasonic sensors. Specifically, driver assistance systems with ultrasonic sensors are used to support the parking process, known as parking assistance systems. In this case, the parking assistance system forms part of a motor vehicle operating at least semi-autonomously. Besides zero-fault hardware, reliable operation also requires detecting, for example, when the ultrasonic sensor is unavailable. A common challenge with ultrasonic sensors relates to dirt detection, which degrades detection performance and thus reduces reliability, particularly for semi-autonomous vehicles. For example, dirt caused by snow is often undetectable. Existing technologies have disclosed schemes such as open-field-of-view testing. This involves configuring the ultrasonic sensor to its maximum sensitivity, and the detection probability during this period is used to conclude that the sensor is generally able to detect something and is therefore not contaminated by snow. The drawback is that no functionality is available during this test because the ultrasonic sensor is operating outside of its normal configuration.

[0003] DE 101 21 519A1 discloses the detection of external substances, such as snow or mud, adhering to an ultrasonic sensor. An obstacle reflects waves emitted from the ultrasonic sensor, which receives the direct wave and thus detects the obstacle. The ultrasonic sensor generates the direct wave that is directly received by the sensor, and is therefore designed to monitor this direct wave. When external substances, such as snow or mud, adhere to the ultrasonic sensor, the direct wave is attenuated, and the presence of the external substance is detected based on this attenuation.

[0004] DE 199 24 755A1 provides a distance measuring device for measuring the distance to an object based on a wave signal emitted by the distance measuring device and reflected by the object. The distance measuring device has transmitting / receiving means for emitting and receiving wave signals using at least first and second transmitting and / or receiving units spatially spaced apart from each other, wherein the first transmitting and / or receiving unit has at least one transmitting function and the second transmitting and / or receiving unit has at least one receiving function. The two units are designed such that the second unit can receive the wave signal emitted by the first unit as a crosstalk signal, and either the first or second unit can receive the wave signal emitted by the first unit as a reflected signal. The distance measuring device also includes an interference determination means for determining at least one characteristic parameter of the crosstalk signal received in the second unit and for determining interference based on the determined characteristic parameter.

[0005] DE 10 2011 118 643 A1 relates to a driver assistance device for a motor vehicle, having a first ultrasonic sensor with a diaphragm for emitting and receiving ultrasonic waves and a second ultrasonic sensor with a diaphragm for emitting and receiving ultrasonic waves, wherein the first ultrasonic sensor has a first resonant frequency and the second ultrasonic sensor has a second resonant frequency different from the first resonant frequency. A control device actuates the ultrasonic sensors and is designed to switch at least the first ultrasonic sensor between a first operating mode and a second operating mode, wherein in the first operating mode, the first ultrasonic sensor emits ultrasonic waves at the first resonant frequency, and in the second operating mode, the first ultrasonic sensor emits ultrasonic waves at the second resonant frequency. Summary of the Invention

[0006] The object of this invention is to provide a method, a computer program product, a computer-readable storage medium, an ultrasonic sensor device, and an auxiliary system that can be used to determine dirt on an ultrasonic sensor in an improved manner.

[0007] This objective is achieved by the method, computer program product, computer-readable storage medium, ultrasonic sensor device, and auxiliary system according to the independent claims. Advantageous embodiments are specified in the dependent claims.

[0008] One aspect of the invention relates to a method for determining contamination of a first ultrasonic sensor of an ultrasonic sensor device for an auxiliary system of a motor vehicle, wherein the first ultrasonic sensor is used to transmit a first ultrasonic signal into the environment of the motor vehicle and to receive a first ultrasonic signal reflected in the environment, and wherein a second ultrasonic sensor of the ultrasonic sensor device is used to transmit a second ultrasonic signal, different from the first ultrasonic signal, into the environment substantially simultaneously with the first ultrasonic signal.

[0009] The first ultrasonic sensor is specified to receive a second ultrasonic signal reflected in the environment, and the received first ultrasonic signal and the received second ultrasonic signal are compared by an electronic computing device of the ultrasonic sensor device, and the comparison is used as the basis for determining the contaminant by the electronic computing device.

[0010] Therefore, contaminant identification can be performed in an improved manner. In the present case, dust is intended to be understood as material adhering to the ultrasonic sensor, particularly the first ultrasonic sensor. In particular, snow, for example, on the first ultrasonic sensor can be considered as contaminant.

[0011] For example, snow prevents the diaphragm of an ultrasonic sensor from vibrating properly. Therefore, the function of the first ultrasonic sensor is at least limited. Specifically, snow means that the function of the first ultrasonic sensor cannot be fully provided. If the auxiliary system still evaluates the applicable signal from the first ultrasonic sensor in the presence of dirt, it may lead to false measurements. Therefore, the ability to reliably detect dirt in the first ultrasonic sensor is crucial.

[0012] This invention leverages the fact that extending ultrasonic sensors by modulating signals means they can not only transmit and receive signals simultaneously but also be distinguishable from each other. This parallel operation provides a solution to open-field-of-view testing problems without altering the configuration of the ultrasonic sensors or interrupting end-user functionality (i.e., parking functions). Simultaneously comparing two different ultrasonic signals specifically means that a first ultrasonic sensor transmits and receives signals, and that the first ultrasonic sensor simultaneously receives a second ultrasonic signal from an adjacent ultrasonic sensor, which in this context is, in other words, the second ultrasonic sensor. Under normal circumstances, simultaneous measurements always result in different waveforms for the two ultrasonic signals. For example, in the case of snow-induced dirt, the two waveforms are essentially identical and neither contains any reflection points.

[0013] In other words, the method according to the invention utilizes the possibility that an ultrasonic sensor emits encoded, i.e., distinguishable ultrasonic signals. The ultrasonic sensor is able to extract the two encoded echoes from a received signal, for example, containing two superimposed encoded echoes. Now assuming the first ultrasonic sensor is blocked, the signals in the two extracted ultrasonic signals essentially contain only sensor noise. That is, if the two encoding results are the same, there is a blockage. If the encoding results are different, there is no contamination.

[0014] These two ultrasonic signals are preferably transmitted in parallel, that is, simultaneously. In the present context, "simultaneously" is intended to be understood in particular to mean that the first and second ultrasonic signals are transmitted without any time delay. Of course, the technical environment may imply a minimal time difference during transmission; however, this time difference is ignored in the present context for the purpose of explaining the method according to the invention.

[0015] According to an advantageous embodiment, a first received ultrasonic signal is used as the basis for a first reception curve, and a second received ultrasonic signal is used as the basis for a second reception curve. These first and second reception curves are generated by an electronic computing device, and the first and second reception curves are compared. Specifically, the reception curves have a reception amplitude that changes over time. Echoes appear within the reception curves based on reflections, such as reflections from the ground. Comparison of the reception curves can be used to determine whether the first ultrasonic sensor is contaminated. Specifically, if the two reception curves are substantially different, contamination can be considered absent. If the reception curves are substantially matched, contamination can be considered present. In particular, in the case of contamination, the reception curves show no echo amplitude. This can also be used to identify contamination in the first ultrasonic sensor.

[0016] Advantageously, if the received first ultrasonic signal differs from the received second ultrasonic signal, it is determined that the first ultrasonic sensor is free of contaminants. Specifically, if the two received ultrasonic signals differ from each other, it can be assumed that the open space test is positive and that the first ultrasonic sensor is free of contaminants. Therefore, it can be concluded that the first ultrasonic sensor is functioning normally.

[0017] Furthermore, it has been found that, advantageously, if the received first ultrasonic signal matches the received second ultrasonic signal, it is determined that the first ultrasonic sensor is contaminated. Specifically, the received signals are substantially matched. If the comparison results show that the first and second ultrasonic signals are substantially identical, then it can be inferred that the first ultrasonic sensor is contaminated. This then informs the assistance system of this situation, allowing it to ignore the evaluation of the ultrasonic signal from that ultrasonic sensor, for example, in the case of a parking function.

[0018] In another advantageous embodiment, the first ultrasonic signal is emitted in a frequency band different from that of the second ultrasonic signal. Emission in different frequency bands allows for the emission of different ultrasonic signals. Therefore, appropriate extraction from the first ultrasonic sensor can be used to reliably distinguish between the first and second ultrasonic signals. This allows for a reliable comparison of the two ultrasonic signals.

[0019] It is also advantageous if the first ultrasonic signal is transmitted with a phase modulation different from that of the second ultrasonic signal. Phase modulation causes a phase shift within the transmitted signal. Therefore, phase modulation can reliably distinguish between the first and second ultrasonic signals. This allows for the reliable determination of contaminants.

[0020] Furthermore, it has been found that it is advantageous if the first ultrasonic signal is transmitted with frequency modulation different from that of the second ultrasonic signal. Specifically, the first ultrasonic signal thus has a frequency modulation different from that of the second ultrasonic signal. This allows for reliable differentiation between the first and second ultrasonic signals by the first ultrasonic sensor. Therefore, a reliable comparison can be performed, thereby enabling reliable dirt determination.

[0021] According to another advantageous embodiment, a first ultrasonic signal is transmitted modulated at a frequency that increases over time, while a second ultrasonic signal is transmitted modulated at a frequency that decreases over time; or, the first ultrasonic signal is transmitted modulated at a frequency that decreases over time, while the second ultrasonic signal is transmitted modulated at a frequency that increases over time. An ultrasonic signal with a frequency that increases over time can also be referred to as a chirp-up signal. An ultrasonic signal with a frequency that decreases over time can also be referred to as a chirp-down signal. In particular, for example, the first ultrasonic signal is transmitted as a chirp-up signal, and then the second ultrasonic signal is transmitted as a chirp-down signal. Alternatively, the reverse can also be performed. This allows the first ultrasonic sensor to reliably distinguish between the first and second ultrasonic signals. Therefore, a reliable comparison can be performed on the two ultrasonic signals. This advantageously allows for the identification of contaminants.

[0022] It is also advantageous to consider the sensor noise of the first ultrasonic sensor when identifying contaminants. In particular, even in the presence of contaminants, sensor noise will cause the first ultrasonic signal to differ from the second ultrasonic signal. This is especially true based on noise within the sensor. Considering the internal noise of the sensor allows for reliable identification of contaminants.

[0023] Advantageously, the correlation filter of the first ultrasonic sensor can be used to extract the first and second ultrasonic signals from each other. The correlation filter allows for reliable extraction of the first and second ultrasonic signals. Therefore, a reliable comparison of the two ultrasonic signals can be performed.

[0024] In another advantageous embodiment, dirt determination is performed before the trip begins. For example, an open space test can be performed after the vehicle is started. For example, the first and second ultrasonic signals can be emitted after the user enters the vehicle and the ignition is started. This means that a dirt check can be performed before the trip actually begins. Alternatively or additionally, dirt determination can also be performed during driving, particularly at predetermined time intervals. It can also be specified that an appropriate dirt check is performed, for example, after the user presses the stop button, so that the user can initiate the parking process.

[0025] The method according to the invention is particularly a computer-implemented method.

[0026] Another aspect of the invention relates to a computer program product having program code means stored in a computer-readable medium for performing a method for determining dirt on a first ultrasonic sensor according to the foregoing aspects when the computer program product is run on a processor of an electronic computing device.

[0027] Another aspect of the present invention relates to a computer-readable storage medium having a computer program product according to the foregoing aspects. This computer-readable storage medium can in particular be designed as part of an electronic computing device.

[0028] Another aspect of the invention relates to an ultrasonic sensor device for a motor vehicle, having at least one first ultrasonic sensor, a second ultrasonic sensor, and an electronic computing device, the ultrasonic sensor device being designed to perform the method according to the foregoing aspect. In particular, the method is performed by the ultrasonic sensor device.

[0029] Another aspect of the present invention relates to an auxiliary system having an ultrasonic sensor device according to the foregoing aspects.

[0030] Another aspect of the invention relates to a motor vehicle having an auxiliary system according to the foregoing aspects. This motor vehicle is at least semi-automatic, and particularly fully automatic. Furthermore, this motor vehicle is especially in the form of a passenger vehicle.

[0031] This method is intended to be viewed as an advantageous configuration for computer program products, computer-readable storage media, ultrasonic sensor devices, auxiliary systems, and motor vehicles. Therefore, the ultrasonic sensor device, the auxiliary system, and the motor vehicle have specific features that allow the implementation of the method and its advantageous embodiments. Attached Figure Description

[0032] Other features of the invention will be apparent from the claims, drawings, and description of the drawings. Without departing from the scope of the invention, the features and combinations of features referenced in the above description, as well as the features and combinations of features referenced in the following description of the drawings and / or shown individually in the drawings, can be used not only in the separately indicated combinations but also in other combinations. Therefore, the invention is also intended to be considered as including and disclosing embodiments not explicitly shown and explained in the drawings, but which can be derived from the explained embodiments through discrete combinations of features. Therefore, embodiments and combinations of features that do not have all the features of the initially stated independent claims should also be considered disclosed. Embodiments and combinations of features that exceed or differ from the combinations of features set forth in the following references to the claims should also be considered disclosed, particularly by way of the above-described embodiments.

[0033] The invention will now be explained in more detail using preferred exemplary embodiments and with reference to the accompanying drawings.

[0034] In the attached image:

[0035] Figure 1 A schematic plan view of an embodiment of a motor vehicle having an auxiliary system is shown;

[0036] Figure 2 A schematic graph of the received ultrasonic signal is shown; and

[0037] Figure 3 Another schematic graph of the received ultrasonic signal is shown.

[0038] In the accompanying drawings, the same elements or elements with the same function have the same reference numerals. Detailed Implementation

[0039] Figure 1 A schematic plan view of an embodiment of a motor vehicle 1 with an assistance system 2 is shown. The assistance system 2 can be implemented, for example, as a parking assistance system 2. The motor vehicle 1 can be at least semi-automatic, and particularly fully automatic. The motor vehicle 1 or the assistance system 2 has an ultrasonic sensor device 3. In this illustrative embodiment, the ultrasonic sensor device 3 has two ultrasonic sensors 4 and 5. It should be noted that this is purely illustrative. The ultrasonic sensor device 3 may also have additional ultrasonic sensors 4 and 5. In this exemplary embodiment, the ultrasonic sensor device 3 is formed on the front of the motor vehicle 1. It goes without saying that the ultrasonic sensor device 3 may also be formed, for example, on the rear end and / or side of the motor vehicle 1.

[0040] In order to perform the method according to the invention, the ultrasonic sensor device 3 also includes an electronic computing device 6. The electronic computing device 6 further includes, for example, a computer-readable storage medium and a computer program product, which are not shown in the present example.

[0041] A method for determining dirt in the first ultrasonic sensor 4 of the ultrasonic sensor device 3 of the auxiliary system 2 of a motor vehicle 1 includes: the first ultrasonic sensor 4 for emitting a first ultrasonic signal 7 into the environment 8 of the motor vehicle 1 and receiving the first ultrasonic signal 7 reflected in the environment 8 by the first ultrasonic sensor 4; and a second ultrasonic sensor 5 for emitting a second ultrasonic signal 9, different from the first ultrasonic signal 7, into the environment 8 substantially simultaneously with the first ultrasonic signal 7.

[0042] The first ultrasonic sensor 4 is specified to receive the second ultrasonic signal 9 reflected in the environment 8, and the received first ultrasonic signal 7 is compared with the received second ultrasonic signal 9 by the electronic computing device 6 of the ultrasonic sensor device 3, and the comparison is specified as the basis for determining the contaminant by the electronic computing device 6.

[0043] Specifically, the first ultrasonic signal 7 can be specified to be transmitted in a frequency band different from that of the second ultrasonic signal 9. Alternatively or additionally, the first ultrasonic signal 7 can be transmitted with a phase modulation different from that of the second ultrasonic signal 9. Again, alternatively or additionally, the first ultrasonic signal 7 can be transmitted with a frequency modulation different from that of the second ultrasonic signal 9. It can also be specified that the first ultrasonic signal 7 is transmitted with frequency modulation that increases with time t. Figure 2 The first ultrasonic signal 7 is transmitted with frequency modulation decreasing over time t, while the second ultrasonic signal is transmitted with frequency modulation increasing over time t. The ultrasonic signals 7 and 9 with frequency increasing over time are specifically referred to as chirp-up signals. The ultrasonic signals 7 and 9 with frequency decreasing over time t are specifically referred to as chirp-down signals.

[0044] In addition, it can be specifically stipulated that the identification of waste be carried out before the start of the trip.

[0045] Figure 2 A schematic diagram of the different received ultrasonic signals 7 and 9 is shown. In the current example, ultrasonic signals 7 and 9 are specifically shown as received curves 10 and 11. Time t is plotted on the horizontal axis, and amplitude is plotted on the vertical axis. In particular, Figure 2 The receiving curves 10 and 11 with applicable echoes are shown, which are illustrated by different amplitudes applicable to different times t.

[0046] Specifically, the current example shows that a first received ultrasonic signal 7 is used as the basis for a first received curve 10, and a second received ultrasonic signal 9 is used as the basis for a second received curve 11. The first received curve 10 and the second received curve 11 are generated by an electronic computing device 6, and the first received curve 10 and the second received curve 11 are compared. Figure 2 Specifically, it is shown that the ultrasonic signals 7 and 9, or the reception curves 10 and 11, are different from each other. In particular, if the received first ultrasonic signal 7 is different from the received second ultrasonic signal 9, it can be determined that the first ultrasonic sensor 4 is free of dirt.

[0047] As shown in the current example, a correlation filter can be used to extract ultrasonic signals 7 and 9. Therefore, the first ultrasonic signal 7 and the second ultrasonic signal 9 can be reliably distinguished.

[0048] therefore, Figure 2 The so-called envelopes are specifically shown. The first reception curve 10 represents the direct measurement of the first ultrasonic signal 7 emitted by the first ultrasonic sensor 4, and the second reception curve 11 represents the indirect measurement of the second ultrasonic signal 9 emitted by the second ultrasonic sensor 5. Due to different reflections, such as different reflections from the ground, these two reception curves 10 and 11 are significantly different from each other.

[0049] Figure 3 Another schematic diagram related to the received ultrasonic signals 7 and 9 is shown. Figure 3 The first reception curve 10 and the second reception curve 11 are shown again. In this current example, it can be particularly seen that the match between the first reception curve 10 and the second reception curve 11, or the match between the first ultrasonic signal 7 and the second ultrasonic signal 9, can essentially be recorded. Specifically, if the received first ultrasonic signal 7 matches the second ultrasonic signal 9, it can be determined that there is dirt on the first ultrasonic sensor 4. In particular, Figure 3 The first ultrasonic sensor 4 is shown to be unable to detect anything due to dirt, which is characterized in particular by the fact that the first reception curve 10 and the second reception curve 11 no longer contain any echoes and are essentially the same.

[0050] Specifically, it can be seen that as time t progresses, especially at later reception times, background noise is revealed, which is amplified with distance. In particular, it can be specified at this time that the sensor noise of the first ultrasonic sensor 4 is considered when determining contaminants.

[0051] The proposed method is particularly useful for obtaining contaminants within a single measurement cycle. Specifically, the ultrasonic sensor device 3 requires no additional configuration. Furthermore, there is no need to interrupt the function of the ultrasonic sensor device 3, such as a parking function. The current example also relates to a simple method, such as by comparing floating averages or by subtracting the two reception curves 10, 11, or other very simple comparison methods. Moreover, the method according to the invention is independent of the modulation type.

[0052] In particular, Figures 1 to 3 The blind detection of the first ultrasonic sensor 4 by channel comparison is shown.

Claims

1. A method for determining dirt of a first ultrasonic sensor (4) of an ultrasonic sensor device (3) of an assistance system (2) of a motor vehicle (1), wherein The first ultrasonic sensor (4) is used to transmit a first ultrasonic signal (7) into the environment (8) of the motor vehicle (1), and to receive the first ultrasonic signal (7) reflected in the environment (8) by the first ultrasonic sensor (4), wherein the second ultrasonic sensor (5) of the ultrasonic sensor device (3) is used to transmit a second ultrasonic signal (9) different from the first ultrasonic signal (7) into the environment (8) substantially simultaneously with the first ultrasonic signal (7). Its features The first ultrasonic sensor (4) is used to receive a second ultrasonic signal (9) reflected in the environment (8), and the received first ultrasonic signal (7) is compared with the received second ultrasonic signal (9) by the electronic computing device (6) of the ultrasonic sensor device (3), and the comparison is used as the basis for determining the dirt by the electronic computing device (6). If the received first ultrasonic signal (7) is different from the received second ultrasonic signal (9), it is determined that the first ultrasonic sensor (4) is free of dirt; if the received first ultrasonic signal (7) matches the received second ultrasonic signal (9), it is determined that the first ultrasonic sensor (4) is free of dirt.

2. The method according to claim 1, Its features The first received ultrasonic signal (7) is used as the basis for the first receiving curve (10), and the second received ultrasonic signal (9) is used as the basis for the second receiving curve (11). The first receiving curve (10) and the second receiving curve (11) are generated by the electronic computing device (6), and the first receiving curve (10) and the second receiving curve (11) are compared.

3. The method according to claim 1 or 2, Its features The first ultrasonic signal (7) is emitted in a frequency band different from that of the second ultrasonic signal (9).

4. The method according to claim 1 or 2, Its features The first ultrasonic signal (7) is transmitted with a phase modulation different from that of the second ultrasonic signal (9).

5. The method according to claim 1 or 2, Its features The first ultrasonic signal (7) is transmitted at a frequency different from that of the second ultrasonic signal (9).

6. The method according to claim 5, Its features The first ultrasonic signal (7) is transmitted with frequency modulation that increases with time (t), while the second ultrasonic signal (9) is transmitted with frequency modulation that decreases with time (t), or the first ultrasonic signal (7) is transmitted with frequency modulation that decreases with time (t), while the second ultrasonic signal (9) is transmitted with frequency modulation that increases with time (t).

7. The method according to claim 1 or 2, Its features When determining the contaminant, the sensor noise of the first ultrasonic sensor (4) is taken into account.

8. The method according to claim 1 or 2, Its features The correlation filter of the first ultrasonic sensor (4) is used to extract the first ultrasonic signal (7) and the second ultrasonic signal (9) from each other.

9. The method according to claim 1 or 2, Its features The identification of the contaminants shall be performed before the trip begins.

10. A computer program product having program code means stored in a computer-readable storage medium to perform the method according to any one of claims 1 to 9 when the computer program product is run on a processor of an electronic computing device (6).

11. A computer-readable storage medium having a computer program product according to claim 10.

12. An ultrasonic sensor device (3) for a motor vehicle (1), having at least one first ultrasonic sensor (4), having a second ultrasonic sensor (5) and having an electronic computing device (6), said ultrasonic sensor device (3) being designed to perform the method according to any one of claims 1 to 9.

13. An auxiliary system (2) having an ultrasonic sensor device (3) according to claim 12.

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