Controller and method for control

Abstract

To provide a controller which can correctly distinguish between an unnecessary resonance of an ultrasonic sensor and an obstacle by using a wave width of the ultrasonic sensor.SOLUTION: A controller 20 according to the present disclosure includes an acquisition circuit 22 and a determination circuit 23. The acquisition circuit 22 acquires a wave width. The determination circuit 23 makes a determination on the basis of the magnitude of the wave width received from the acquisition circuit 22 and thus correctly distinguishes between a resonance of an ultrasonic sensor 10 and an obstacle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a control device and a control method. [Background technology]

[0002] There is known an existing technology that uses a distance measuring sensor such as an ultrasonic sensor mounted on a vehicle to detect objects such as a preceding vehicle, an obstacle, or a pedestrian. In addition, there is known a technology that performs various controls to improve the traveling safety of the vehicle, such as activating an automatic brake or notifying the driver, based on the object detection result by the distance measuring sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-081050 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, with existing technology, it is difficult to correctly distinguish between unwanted resonance of the ultrasonic sensor and sound reflected from an obstacle. For example, it is difficult to correctly distinguish between resonance caused by adhesion to the ultrasonic sensor, temperature fluctuation, and variation in the ultrasonic sensor itself, and sound reflected from an obstacle.

[0005] The present disclosure provides a control device that can correctly distinguish between unwanted resonance of an ultrasonic sensor and sound reflected from an obstacle. [Means for solving the problem]

[0006] The control device according to the present disclosure is characterized by having an acquisition circuit that acquires the wave width of the ultrasonic wave transmitted by the ultrasonic sensor, and a judgment circuit that determines that resonance occurs when the wave width of the ultrasonic wave acquired by the acquisition circuit is smaller than a threshold value. Effect of the Invention

[0007] The disclosed device can correctly distinguish between unwanted resonance of the ultrasonic sensor and an obstacle using the wave width from the ultrasonic sensor. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a detection system according to an embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of a measurement unit according to the embodiment. [Diagram 3] FIG. 3 is a diagram for explaining resonance and reflected sound from an obstacle. [Figure 4] FIG. 4 is a diagram for explaining a threshold value used for determining whether an unwanted resonance exists or an obstacle exists. [Diagram 5] FIG. 5 is a diagram for explaining a threshold value used for determining whether an unwanted resonance exists or an obstacle exists. [Figure 6] FIG. 6 is a diagram for explaining a threshold value used for determining whether an unwanted resonance exists or an obstacle exists. [Figure 7] FIG. 7 is a flowchart showing an example of the flow of the determination process according to the embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of the configuration of the measurement unit according to the embodiment. [Figure 9] FIG. 9 is a diagram illustrating an example of detection of a close-range object according to the embodiment. [Figure 10] FIG. 10 is a diagram illustrating an example of detection of adhesion of a foreign matter according to the embodiment. [Figure 11] FIG. 11 is a flowchart showing an example of the flow of the determination process according to the embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of a hardware configuration of the control device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of a detection system according to the present disclosure will be described with reference to the drawings. Note that, in the following, an example in which the detection system 1 is mounted on a vehicle will be described, but the present invention is not limited to this.

[0010] 1. First embodiment [1-1. Example of detection system configuration] 1, the detection system 1 includes an ultrasonic sensor 10, a control device 20, a display device 30, and an alarm device 40. In this embodiment, the detection system 1 includes the ultrasonic sensor 10, the control device 20, the display device 30, and the alarm device 40. Note that the detection system 1 may be equipped with further components.

[0011] 1, the ultrasonic sensor 10, the control device 20, the display device 30, and the alarm device 40 are illustrated as separate units, but some or all of these units may be integrated. The ultrasonic sensor 10 includes a microphone 11, a transmitting unit 12, a receiving unit 13, and a measuring unit 14.

[0012] The transmitting unit 12 causes the microphone 11 to transmit ultrasonic waves. For example, the transmitting unit 12 receives a signal from the transmission control unit 21 and causes the microphone 11 to transmit ultrasonic waves.

[0013] The microphone 11 transmits and receives ultrasonic waves. For example, the microphone 11 transmits ultrasonic waves in response to a signal from the transmission unit 12, and receives the reflected sound that is returned when the ultrasonic waves hit an object.

[0014] The receiving unit 13 receives the reflected sound of the ultrasonic wave. For example, the receiving unit 13 receives the reflected sound of the ultrasonic wave received by the microphone 11 and converts it into an electrical signal.

[0015] The measuring unit 14 acquires the amplitude of the reflected ultrasonic sound based on the electrical signal received from the transmitting unit 12 to cause the microphone 11 to transmit ultrasonic waves and the electrical signal of the reflected ultrasonic sound received from the receiving unit 13.

[0016] The control device 20 includes a transmission control unit 21, an acquisition unit 22, a determination unit 23, an output unit 24, and a storage unit 25. Each unit included in the control device 20 will be described below.

[0017] The transmission control unit 21 sends an electric signal to the transmission unit 12 to control the transmission of ultrasonic waves by the microphone 11 .

[0018] The acquisition unit 22 acquires the amplitude of the ultrasonic waves transmitted by the ultrasonic sensor. The acquisition unit 22 also acquires the reverberation end time of the ultrasonic waves transmitted by the ultrasonic sensor. For example, the acquisition unit 22 acquires the amplitude of the ultrasonic waves transmitted by the ultrasonic sensor and the reverberation end time of the ultrasonic waves from the measurement unit 14 described later.

[0019] Here, the reverberation end time refers to the time from when an electrical signal for transmitting an ultrasonic wave is sent from the transmitting unit 12 described later to the microphone 11 until the electrical signal converted by the receiving unit 13 becomes smaller than a predetermined threshold value. Note that the reverberation end time is not limited to this, and may be the time from when the vibration of the microphone 11 ends until the electrical signal converted by the receiving unit 13 becomes smaller than a predetermined threshold value.

[0020] The determination unit 23 determines that resonance occurs when the amplitude of the ultrasonic wave acquired by the acquisition unit 22 is smaller than a threshold value. For example, the determination unit 23 determines that resonance occurs when the amplitude of the ultrasonic wave acquired by the acquisition unit 22 is less than two-fifths of the reverberation time.

[0021] As a specific example, the determination unit 23 determines that there is resonance because the ultrasonic wave width "100 μs" acquired by the acquisition unit 22 is less than "680 μs", which is two-fifths of the reverberation time "1700 μs". Also, for example, the determination unit 23 determines that there is no resonance because the ultrasonic wave width "700 μs" acquired by the acquisition unit 22 is equal to or greater than "680 μs", which is two-fifths of the reverberation time "1700 μs".

[0022] The output unit 24 outputs the result of the determination made by the determination unit 23 to an external device such as the display device 30 or the alarm device 40. For example, when the determination unit 23 determines that resonance is occurring in the ultrasonic sensor 10, the output unit 24 causes the display device 30 to display a message notifying that resonance is occurring in the ultrasonic sensor 10. Note that when the determination unit 23 determines that resonance is occurring in the ultrasonic sensor 10, the detection system 1 may stop the detection process by the detection system 1.

[0023] Also, for example, when the determination unit 23 detects an obstacle, the output unit 24 causes the display device 30 to display a message notifying the presence of the obstacle. Also, for example, when the determination unit 23 detects an obstacle, the output unit 24 causes the warning device 40 to output a warning notifying the presence of an object.

[0024] The storage unit 25 stores values ​​used in the judgment performed by the judgment unit 23. For example, the storage unit 25 stores a wave amplitude, a reverberation end time, and a wave amplitude threshold value. For example, the storage unit 25 stores values ​​such as a wave amplitude of "170 μs," a reverberation end time of "1700 μs," and a wave amplitude threshold value of "two-fifths of the reverberation time." Note that the stored values ​​are merely examples and are not limited to these.

[0025] The display device 30 receives the output from the output unit 24 and displays content based on the detection result determined by the determination unit 23. For example, when the determination unit 23 determines that resonance is occurring, the display device 30 receives the output from the output unit 24 and displays a message notifying the occurrence of resonance on a monitor portion mounted in the vehicle. At this time, the display device 30 may also display a message notifying that the detection process by the detection system 1 has been stopped.

[0026] The warning device 40 receives the output from the output unit 24 and issues a warning based on the detection result determined by the determination unit 23. For example, when the determination unit 23 determines that there is an obstacle, the warning device 40 may receive the output from the output unit 24 and output a warning by emitting a warning sound of "beep." Also, for example, when the determination unit 23 determines that resonance is occurring, the warning device 40 may receive the output from the output unit 24 and output a warning by emitting a warning sound of "beep." The warning device 40 can issue a warning sound according to the output from the output unit 24 or the content to be conveyed to the operator.

[0027] [1-2. Measurement section configuration] Next, the measurement unit 14 of the control device 100 according to the first embodiment will be described with reference to Fig. 2. As shown in Fig. 2, the measurement unit 14 of this embodiment includes a pulse width measurement unit 14a, a reverberation time measurement unit 14b, and a transmission / reception signal processing unit 14d. Each unit included in the measurement unit 14 will be described below.

[0028] The amplitude measuring unit 14a measures the amplitude of the ultrasonic wave based on the electrical signal from the transmitting unit 12 that transmits the ultrasonic wave to the microphone 11 and the electrical signal of the reverberation and reflected sound of the ultrasonic wave from the receiving unit 13. For example, the amplitude measuring unit 14a measures the amplitude by measuring the time from when the value indicated by the electrical signal converted by the receiving unit 13 starts to rise to when it finishes falling. Note that the amplitude measuring unit 14a can use a predetermined threshold value or a predetermined variation in value to determine when the value indicated by the electrical signal converted by the receiving unit 13 starts to rise and when it finishes falling during amplitude measurement.

[0029] The reverberation time measurement unit 14b measures the reverberation end time based on the electrical signal sent from the transmission unit 12 to the microphone 11 to transmit ultrasonic waves, and the electrical signal of ultrasonic reverberation sent from the reception unit 13. For example, the reverberation time measurement unit 14b measures the reverberation end time by measuring the time from when the electrical signal sent from the transmission unit 12 to the microphone 11 to transmit ultrasonic waves to the microphone 11 is sent to when the electrical signal converted by the reception unit 13 becomes smaller than a predetermined threshold.

[0030] The transmission / reception signal processing unit 14d receives and processes the electrical signals from the transmission unit 12 and the reception unit 13. For example, the transmission / reception signal processing unit 14d receives the electrical signals from the transmission unit 12 and the reception unit 13 and processes the electrical signals so that the amplitude measurement unit 14a and the reverberation time measurement unit 14b can perform measurements.

[0031] [1-3. Resonance detection] Next, detection of resonance by the detection system 1 according to the embodiment will be described with reference to Figures 3 to 6. In the following example, the detection system 1 is mounted on a vehicle, and detects resonance of the ultrasonic sensor 10.

[0032] First, the transmission control unit 21 transmits an electrical signal for transmitting an ultrasonic wave to the microphone 11 via the transmission unit 12. Next, the microphone 11 receives the electrical signal and transmits the ultrasonic wave.

[0033] Next, the microphone 11 receives the reflected sound of the ultrasonic waves hitting an obstacle and sends it to the receiver 13. Next, the receiver 13 converts the reverberation of the ultrasonic waves and the reflected sound into electrical signals. Next, the transmission / reception signal processor 14d receives the electrical signals from the transmitter 12 and the receiver 13 and processes the electrical signals so that the amplitude measurement unit 14a can handle them. In this way, the amplitude measurement unit 14a and the reverberation time measurement unit 14b receive the electrical signals processed by the transmission / reception signal processor 14d and measure the amplitude.

[0034] Here, Fig. 3 is a diagram showing a waveform when an ultrasonic wave is transmitted from the ultrasonic sensor 10. As shown in Fig. 3 (1), when an obstacle is present, the reflected sound hitting the obstacle is measured as a large wave width.

[0035] On the other hand, due to factors such as temperature changes, adhesions to the ultrasonic sensor 10, and variations in the ultrasonic sensor 10, small wave widths (unwanted resonances) occur between the time when the ultrasonic wave is transmitted and the time when reverberation ends, as shown in (2) of Figure 3.

[0036] Next, the acquisition unit 22 acquires the amplitude from the amplitude measurement unit 14a and the reverberation end time from the reverberation time measurement unit 14b. Next, the determination unit 23 performs a determination based on the amplitude and the reverberation end time acquired by the acquisition unit 22.

[0037] Next, the threshold value used for determining whether an unnecessary resonance is present or an obstacle will be described with reference to FIG. 4. FIG. 4 is a diagram in which the amplitude obtained by the unnecessary resonance and the amplitude obtained by the reflected sound of the obstacle are plotted for each distance from the obstacle. The determination unit 23 can use a predetermined threshold value to determine whether an unnecessary resonance is present or an obstacle's reflected sound based on the amplitude. For example, the area above (1) in FIG. 4 is the area of ​​the amplitude obtained by the reflected sound of the obstacle, and the area below (2) in FIG. 4 is the area of ​​the amplitude obtained by the unnecessary resonance. Therefore, the determination unit 23 uses a determination threshold value that can determine whether an unnecessary resonance is present or an obstacle's reflected sound, as shown in (3) in FIG. 4.

[0038] The threshold value used by the determination unit 23 when determining whether the sound is an unwanted resonance or a sound reflected by an obstacle is a value obtained by an experiment in which ultrasonic waves are sent to obstacles placed at various distances and angles, as shown in Fig. 5. This experiment showed that it is possible to determine whether the sound is an unwanted resonance or a sound reflected by an obstacle based on whether the wave width is smaller than two-fifths of the reverberation end time.

[0039] The ultrasonic wave width changes depending on the size of the obstacle, as shown in Figure 6. For example, when the obstacle is a directly facing wall, a wave width of about 900 μs is obtained as shown in Figure 6 (1), but when the obstacle is a pole with a diameter of 100 mm, a wave width of about 800 μs is obtained as shown in Figure 6 (2), and when the obstacle is a pole with a diameter of 30 mm, a wave width of about 750 μs is obtained as shown in Figure 6 (3).

[0040] Then, the determination unit 23 performs the determination using a threshold value obtained by an experiment. For example, when the amplitude of the ultrasonic wave acquired by the acquisition unit 22 is smaller than two-fifths of the reverberation end time, the determination unit 23 determines that the ultrasonic wave is a resonance. On the other hand, when the amplitude of the ultrasonic wave acquired by the acquisition unit 22 is larger than two-fifths of the reverberation end time, the determination unit 23 determines that the ultrasonic wave is a reflected sound from an obstacle.

[0041] [1-4. Flowchart] Next, the flow of the detection process executed by the detection system 1 configured as above will be described with reference to Fig. 7. Note that the steps below may be executed in a different order, and some processes may be omitted.

[0042] First, the acquisition unit 22 acquires the wave width of the ultrasonic wave transmitted by the ultrasonic sensor 10 (step S101). For example, the acquisition unit 22 acquires the wave width of the ultrasonic wave transmitted by the ultrasonic sensor 10 from the measurement unit 14.

[0043] Next, the determination unit 23 determines whether the amplitude of the acquired ultrasonic wave is smaller than the threshold value (step S102). At this time, if the amplitude of the acquired ultrasonic wave is not smaller than the threshold value (step S102 "No"), the determination unit 23 determines that the sound is a reflected sound from an obstacle (step S103).

[0044] On the other hand, if the wave width of the acquired ultrasonic wave is smaller than the threshold value (step S102 "Yes"), it is determined that resonance of the ultrasonic sensor 10 is occurring (S104).

[0045] [1-5. Effects] As described above, the control device 20 according to the embodiment has an acquisition unit 22 that acquires the wave width of the ultrasonic waves transmitted by the ultrasonic sensor 10, and a judgment unit 23 that judges that resonance has occurred when the wave width of the ultrasonic waves acquired by the acquisition unit 22 is smaller than a threshold value.

[0046] As a result, the control device 20 according to the embodiment can correctly distinguish between unwanted resonance of the ultrasonic sensor 10 and sound reflected from an obstacle by determining the wave width of the ultrasonic wave using a threshold value.

[0047] Moreover, the acquisition unit 22 in the control device 20 according to the embodiment acquires the wave width of the ultrasonic waves transmitted by the ultrasonic sensors 10 provided on the front, rear, or sides of the vehicle. As a result, the control device 20 according to the embodiment can correctly distinguish between unnecessary resonance of the ultrasonic sensor and reflected sound from an obstacle by determining the wave width of the ultrasonic waves transmitted by the ultrasonic sensors provided on the front, rear, or sides of the vehicle using a threshold value.

[0048] Furthermore, the determination unit 23 in the control device 20 according to the embodiment uses a value of 2 / 5 of the reverberation end time as a threshold value. This allows the control device 20 according to the embodiment to correctly distinguish between unwanted resonance of the ultrasonic sensor 10 and reflected sound from an obstacle by using the threshold value of 2 / 5 of the reverberation end time as the normal width of the ultrasonic wave.

[0049] 2. Second embodiment Up to this point, the first embodiment has been described, but the second embodiment will be described below. Note that the same description as in the first embodiment will be omitted as appropriate. In the second embodiment, the control device 100 further uses information on the reverberation time and the reverberation frequency to distinguish between the adhesion of a foreign object and an obstacle existing in the vicinity of the ultrasonic sensor 10. Note that the reverberation frequency refers to the frequency during the time from when the vibration of the microphone 11 ends until the electric signal converted by the receiving unit 13 becomes smaller than a predetermined threshold value.

[0050] [2-1. Example of detection system configuration] Next, the configuration of the control device 100 will be described with reference to Fig. 1. Each unit of the control device 100 will be described below, but a description of the same processes as those in the first embodiment will be omitted.

[0051] The acquisition unit 22 further acquires a reverberation end time and a reverberation frequency. For example, the acquisition unit 22 acquires the reverberation end time and the reverberation frequency from the measurement unit 14.

[0052] The determination unit 23 determines whether a foreign object is attached to the ultrasonic sensor 10 or whether a nearby object is present near the ultrasonic sensor 10, based on the reverberation end time and the reverberation frequency acquired from the acquisition unit 22. For example, the determination unit 23 determines whether the reverberation end time of the ultrasonic wave is longer than a predetermined threshold. As a result, when the reverberation end time is longer than the predetermined threshold, the determination unit 23 determines whether the difference between the reverberation frequency and the natural frequency of the microphone 11 is within a predetermined range. On the other hand, when the reverberation end time of the ultrasonic sound is shorter than the predetermined threshold, the determination unit 23 performs the process described in the first embodiment.

[0053] The determination unit 23 further determines that there is a nearby object when the difference between the natural frequency of the microphone 11 and the reverberation frequency is within a predetermined range. At this time, the determination unit 23 determines that a foreign object is attached to the ultrasonic sensor 10 when the difference between the natural frequency of the microphone 11 and the reverberation frequency exceeds the predetermined range. In addition, for example, the determination unit 23 determines whether the reverberation end time of the ultrasonic waves is shorter than a predetermined threshold. At this time, the determination unit 23 determines that there is thin ice on the ultrasonic sensor 10 when the reverberation end time is shorter than the predetermined threshold.

[0054] As a specific example, a case will be described in which the acquisition unit 22 acquires "2100 μs" as the reverberation end time and "54950 Hz" as the reverberation frequency, and the natural frequency of the microphone 11 is "55000 Hz." First, the determination unit 23 determines that the reverberation end time of 2100 μs acquired from the acquisition unit 22 is longer than the threshold value of 1700 μs. Then, the determination unit 23 determines that the difference between the natural frequency of the microphone 11, 55000 Hz, and the reverberation frequency, 54950 Hz, is within ±0.1% of the natural frequency of the microphone 11, 55000 Hz. In this way, the determination unit 23 determines that a close-range object is present in the vicinity of the ultrasonic sensor 10.

[0055] The threshold value is not limited to this. In addition, the determination unit 23 can detect the state of the ultrasonic sensor 10, such as the adhesion of a foreign object to the ultrasonic sensor 10, the formation of thin ice on the ultrasonic sensor 10, etc., in addition to the close-range object existing near the ultrasonic sensor 10, based on the reverberation characteristics such as the reverberation end time and the reverberation frequency.

[0056] The output unit 24 outputs the result of the determination by the determination unit 23 to an external device such as the display device 30 or the alarm device 40. For example, when the determination unit 23 detects that a foreign object has adhered to the ultrasonic sensor 10, the output unit 24 causes the display device 30 to display a message notifying that a foreign object has adhered to the ultrasonic sensor 10. Also, for example, when the determination unit 23 detects a close-range object, the output unit 24 causes the display device 30 to display a message notifying that a close-range object is present. Also, for example, when the determination unit 23 detects a close-range object, the output unit 24 causes the alarm device 40 to output an alarm notifying that a close-range object is present.

[0057] Next, the storage unit 25 stores values ​​used in the determination performed by the determination unit 23. For example, the storage unit 25 stores "1700 μs" and "800 μs" as thresholds for the reverberation end time, and "55000 Hz" as the natural frequency of the microphone 11. Note that the stored values ​​are merely examples and are not limited to these.

[0058] Next, the display device 30 receives the output from the output unit 24 and displays content based on the detection result determined by the determination unit 23. For example, when the determination unit 23 determines that a foreign object is attached to the ultrasonic sensor 10, the display device 30 receives the output from the output unit 24 and displays a message conveying the detection result of the foreign object attachment on a monitor portion mounted in the vehicle. Also, for example, when the determination unit 23 determines that there is a close-range object, the display device 30 displays a message conveying the detection result of the close-range object on a monitor portion mounted in the vehicle.

[0059] Then, the alarm device 40 receives the output from the output unit 24 and issues a warning based on the detection result determined by the determination unit 23. For example, when the determination unit 23 determines that there is a nearby object, the alarm device 40 receives the output from the output unit 24 and outputs a warning by emitting a warning beep.

[0060] [2-2. Measurement section configuration] Next, the measurement unit 14 of the control device 100 according to the second embodiment will be described with reference to Fig. 8. The measurement unit 14 of the control device 100 according to the second embodiment differs from the measurement unit 14 shown in Fig. 2 in that it further includes a reverberation frequency measurement unit 14c.

[0061] As shown in Fig. 8, the measurement unit 14 of the second embodiment includes a pulse width measurement unit 14a, a reverberation time measurement unit 14b, a reverberation frequency measurement unit 14c, and a transmission / reception signal processing unit 14d. Each unit of the measurement unit 14 will be described below. Note that descriptions similar to those of the first embodiment will be omitted as appropriate.

[0062] The reverberation frequency measuring unit 14c measures the reverberation frequency based on the electrical signal from the receiving unit 13. For example, the reverberation frequency measuring unit 14c measures the reverberation frequency by measuring the frequency during the reverberation time measured by the reverberation time measuring unit 14b.

[0063] The transmission / reception signal processor 14d receives and processes electrical signals from the transmitter 12 and the receiver 13. For example, the transmission / reception signal processor 14d receives electrical signals from the transmitter 12 and the receiver 13, and processes the electrical signals so that the amplitude measurement unit 14a, the reverberation time measurement unit 14b, and the reverberation frequency measurement unit 14c can perform measurements.

[0064] 2-3. Detection of close-range objects Next, detection of a close-range object according to the embodiment will be described with reference to Fig. 9. In the following example, a detection system 1 is mounted on a vehicle, and detects a close-range object present in the vicinity of an ultrasonic sensor 10. First, a transmission control unit 21 sends an electrical signal for transmitting an ultrasonic wave to a microphone 11 via a transmission unit 12. Next, the microphone 11 receives the electrical signal and transmits an ultrasonic wave.

[0065] Next, the microphone 11 receives the reverberation generated when the ultrasonic waves are transmitted and the reflected sound when the ultrasonic waves hit a wall, and sends them to the receiver 13. Next, the receiver 13 converts the reverberation and the reflected sound caused by the transmitted ultrasonic waves into electrical signals. Next, the transmission / reception signal processor 14d receives the electrical signals from the transmitter 12 and the receiver 13, and processes the electrical signals so that they can be handled by the reverberation time measurement unit 14b and the reverberation frequency measurement unit 14c.

[0066] In this way, the reverberation time measurement unit 14b receives the electrical signal processed by the transmission / reception signal processor 14d and measures the time until the reverberation ends. The reverberation frequency measurement unit 14c receives the electrical signal processed by the transmission / reception signal processor 14d and measures the reverberation frequency.

[0067] At this time, as shown in (1) of Fig. 9, if there is no short-distance object near the vehicle equipped with the detection system 1, the reverberation end time is not affected by the reflected sound from the short-distance object, as shown in (2) of Fig. 9. On the other hand, as shown in (4) of Fig. 9, if there is a wall near the vehicle equipped with the detection system 1, the reverberation end time becomes longer due to the overlap of the reverberation generated by the transmitted ultrasonic wave and the reflected sound when the ultrasonic wave hits the wall, which is a short-distance object near the vehicle, as shown in (5) of Fig. 9.

[0068] Furthermore, as shown in Fig. 9(1), when there is no close-range object near the vehicle equipped with the detection system 1, as shown in Fig. 9(3), the reverberation frequency hardly fluctuates with respect to the natural frequency of the microphone 11. Furthermore, as shown in Fig. 9(4), when there is a wall near the vehicle equipped with the detection system 1, as shown in Fig. 9(6), the reverberation frequency hardly fluctuates with respect to the natural frequency of the microphone 11.

[0069] Next, the acquisition unit 22 acquires the reverberation end time from the reverberation time measurement unit 14b and the reverberation frequency from the reverberation frequency measurement unit 14c. Next, the determination unit 23 performs a determination based on the reverberation end time and the reverberation frequency acquired by the acquisition unit 22. As a specific example, a case will be described in which the acquisition unit 22 acquires "2100 μs" as the reverberation end time and "54950 Hz" as the reverberation frequency, and the natural frequency of the microphone 11 is "55000 Hz." First, the determination unit 23 determines that the reverberation end time of 2100 μs acquired by the acquisition unit 22 is longer than the reverberation end time threshold value of 1700 μs stored in the storage unit 25.

[0070] Then, the determination unit 23 determines that the difference between the natural frequency 55000 Hz of the microphone 11 stored in the memory unit 25 and the reverberation frequency 54950 Hz acquired by the acquisition unit 22 is within ±0.1% of the threshold value of the natural frequency 55000 Hz of the microphone 11. This allows the detection system 1 to detect the presence of a nearby object.

[0071] On the other hand, if the determination unit 23 determines that the reverberation end time is shorter than the threshold value, the same processing as that described in the first embodiment can be performed.

[0072] [2-4. Detection of foreign matter adhesion] Next, detection of foreign matter adhesion according to the embodiment will be described. In the following example, a detection system 1 is mounted on a vehicle, and detects the adhesion of a foreign matter to an ultrasonic sensor 10.

[0073] First, the transmission control unit 21 transmits an electrical signal for transmitting an ultrasonic wave to the microphone 11 via the transmission unit 12. Next, the microphone 11 receives the electrical signal and transmits the ultrasonic wave.

[0074] Next, the microphone 11 receives the reverberation generated when the ultrasonic waves are transmitted and transmits it to the receiver 13. Next, the receiver 13 converts the reverberation generated when the ultrasonic waves are transmitted into an electrical signal. Next, the transmission / reception signal processor 14d receives the electrical signals from the transmitter 12 and the receiver 13 and processes the electrical signals so that the reverberation time measurement unit 14b and the reverberation frequency measurement unit 14c can handle them. In this way, the reverberation time measurement unit 14b receives the electrical signal processed by the transmission / reception signal processor 14d and measures the reverberation end time. Also, the reverberation frequency measurement unit 14c receives the electrical signal processed by the transmission / reception signal processor 14d and measures the reverberation frequency.

[0075] At this time, as shown in (1) of Fig. 10, if there is no foreign object attached to the ultrasonic sensor 10 of the vehicle equipped with the detection system 1, the reverberation end time is not affected by the attachment of the foreign object, as shown in (2) of Fig. 10. On the other hand, as shown in (4) of Fig. 10, if there is a foreign object attached to the ultrasonic sensor 10 of the vehicle equipped with the detection system 1, the reverberation end time is longer due to the effect of the foreign object attached to the ultrasonic sensor 10, as shown in (5) of Fig. 10.

[0076] Furthermore, as shown in Fig. 10(1), when no foreign object is attached to the ultrasonic sensor 10 of the vehicle equipped with the detection system 1, the reverberation frequency hardly fluctuates with respect to the natural frequency of the microphone 11, as shown in Fig. 10(3). On the other hand, when a foreign object is attached to the ultrasonic sensor 10 of the vehicle equipped with the detection system 1, as shown in Fig. 10(4), the reverberation frequency fluctuates with respect to the natural frequency of the microphone 11 due to the influence of the foreign object attached to the ultrasonic sensor 10, as shown in Fig. 10(6).

[0077] Next, the acquisition unit 22 acquires the reverberation end time from the reverberation time measurement unit 14b and the reverberation frequency from the reverberation frequency measurement unit 14c. Next, the determination unit 23 performs a determination based on the reverberation end time and the reverberation frequency acquired by the acquisition unit 22. As a specific example, a case will be described in which the acquisition unit 22 acquires "2100 μs" as the reverberation end time and "54000 Hz" as the reverberation frequency, and the natural frequency of the microphone 11 is "55000 Hz." First, the determination unit 23 determines that the reverberation end time of 2100 μs acquired by the acquisition unit 22 is longer than the reverberation end time threshold value of 1700 μs stored in the storage unit 25.

[0078] Then, the determination unit 23 determines that the difference between the natural frequency 55000 Hz of the microphone 11 stored in the memory unit 25 and the reverberation frequency 54000 Hz acquired by the acquisition unit 22 is not within ±0.1% of the threshold value of the natural frequency 55000 Hz of the microphone 11. As a result, the detection system 1 detects that a foreign object is attached to the ultrasonic sensor 10.

[0079] [2-5. Flowchart] Next, the flow of the detection process executed by the detection system 1 configured as above will be described with reference to Fig. 11. Note that the following steps may be executed in a different order, and some processes may be omitted.

[0080] First, the acquisition unit 22 acquires the ultrasonic amplitude, the reverberation end time, and the reverberation frequency (step S201). For example, the acquisition unit 22 acquires the ultrasonic amplitude, the reverberation end time, and the reverberation frequency from the measurement unit 14.

[0081] Next, the judgment unit 23 judges whether the reverberation end time is longer than a threshold (step S202). At this time, if the reverberation end time is shorter than the threshold (step S202 "No"), the judgment unit 23 then judges whether the amplitude is smaller than the threshold (step S203). Here, if the amplitude is not smaller than the threshold (step S202 "No"), the judgment unit 23 judges that the sound is a reflected sound from an obstacle (step S204). On the other hand, if the amplitude is smaller than the threshold (step S202 "YES"), the judgment unit 23 judges that the sound is a resonance (step S205).

[0082] On the other hand, if the determination unit 23 determines that the reverberation end time is longer than the threshold (step S202 "YES"), the determination unit 23 then determines whether the reverberation frequency is within the threshold range (step S206). If the reverberation frequency is not within the threshold range (step S206 "NO"), the determination unit 23 determines that a foreign object is attached to the ultrasonic sensor 10 (step S207).

[0083] On the other hand, when the reverberation frequency is within the threshold range (step S206 "YES"), the determination unit 23 determines that a short-distance object is present near the ultrasonic sensor 10 (step S208).

[0084] [2-6. Effects] As described above, the acquisition unit 22 in the control device 20 according to the embodiment further acquires the reverberation end time and reverberation frequency of the ultrasonic waves transmitted by the ultrasonic sensor 10, and the judgment unit 23 judges whether the reverberation end time of the ultrasonic waves acquired by the acquisition unit 22 is longer than a predetermined threshold value, and if it is determined that it is longer, judges whether a foreign object is attached to the ultrasonic sensor 10 or whether an object is present in the vicinity of the ultrasonic sensor 10 based on the predetermined natural frequency and reverberation frequency.

[0085] As a result, the control device 20 of the embodiment acquires the ultrasonic wave width, reverberation end time, and reverberation frequency, and based on the ultrasonic wave reverberation end time and reverberation frequency, can correctly distinguish between foreign matter adhesion and a close-range object, and can also correctly distinguish between unwanted resonance of the ultrasonic sensor 10 and reflected sound from an obstacle.

[0086] In addition, the judgment unit 23 in the control device 20 according to the embodiment further judges whether the difference between the natural frequency and the reverberation frequency is within a predetermined range, and if it is within the predetermined range, judges that an object is present in the vicinity of the ultrasonic sensor, and if it exceeds the predetermined range, judges that a foreign object is attached to the ultrasonic sensor.

[0087] As a result, the control device 20 of the embodiment acquires the ultrasonic wave amplitude, reverberation end time, and reverberation frequency, and uses the difference between the ultrasonic reverberation end time and reverberation frequency to correctly distinguish between foreign matter adhesion and a close-range object, and can correctly distinguish between unwanted resonance of the ultrasonic sensor 10 and reflected sound from an obstacle.

[0088] [3. Hardware Configuration] Next, the hardware configuration of the control device 20 will be described with reference to Fig. 12. As shown in Fig. 12, the control device 20 has a hardware configuration utilizing a normal computer, in which a CPU (Central Processing Unit) 1100A, a ROM (Read Only Memory) 1100B, a RAM (Random Access Memory) 1100C, an I / F (Interface) 1100D, a flash memory 1100E, etc. are interconnected via a bus 1100F.

[0089] The CPU 1100A is an arithmetic device that controls the entire control device 20. The CPU 1100A is an example of a processor, and other processors or processing circuits may be provided instead of the CPU 1100A. The ROM 1100B stores programs and the like that realize various processes by the CPU 1100A. The RAM 1100C is, for example, a main storage device of the control device 20, and stores data used in various processes by the CPU 1100A. The I / F 1100D is an interface for transmitting and receiving data. The flash memory 1100E is an example of a writable non-volatile storage medium. The ROM 1100B, the RAM 1100C, and the flash memory 1100E are also referred to as storage units. The control device 20 may include other storage devices such as a hard disk drive (HDD) instead of or in addition to the flash memory 1100E.

[0090] [4. Other] Although the detection system according to one or more aspects has been described based on the embodiment, the present disclosure is not limited to this embodiment. As long as it does not deviate from the gist of the present disclosure, various modifications conceived by a person skilled in the art to this embodiment and forms constructed by combining components in different embodiments may also be included in the present disclosure.

[0091] The order in which each step is performed in the flowchart is merely an example for specifically explaining the present disclosure, and an order other than the above may be used. In addition, some of the steps may be performed simultaneously (in parallel) with other steps, or some of the steps may not be performed.

[0092] In addition, the division of functional blocks in the block diagram is an example, and multiple functional blocks may be realized as one functional block, one functional block may be divided into multiple blocks, or some functions may be transferred to another functional block. Furthermore, the functions of multiple functional blocks having similar functions may be processed in parallel or in a time-sharing manner by a single piece of hardware or software.

[0093] In addition, in the above-described embodiments, the notation "... part" used for each component may be replaced with other notations such as "... circuitry," "... assembly," "... device," "... unit," or "... module." [Explanation of symbols]

[0094] 1. Detection System 10 Ultrasonic Sensor 11 Microphone 12 Transmitter 13 Receiving section 14 Measurement section 14a Wave width measurement section 14b Reverberation time measurement section 14c Reverberation frequency measurement section 14d Transmission and reception signal processing section 20 Control device 21 Transmission control section 22 Acquisition Department 23 Judgment section 24 Output section 25 Memory section 30 Display device 40 Alarm device

Claims

1. an acquisition circuit for acquiring the wave width of the ultrasonic wave transmitted by the ultrasonic sensor; a determination circuit that determines that resonance has occurred when the wave width of the ultrasonic wave acquired by the acquisition circuit is smaller than a threshold value; A control device having:

2. The control device according to claim 1 , wherein the acquisition circuit acquires the wave width of the ultrasonic waves transmitted by the ultrasonic sensors provided at the front, rear, or sides of the vehicle.

3. The control device according to claim 1 , wherein the threshold value is two-fifths of a reverberation end time.

4. The acquisition circuit further acquires a reverberation end time and a reverberation frequency of the ultrasonic waves transmitted by the ultrasonic sensor, The determination circuit further determines whether the reverberation end time of the ultrasonic wave acquired by the acquisition circuit is longer than a predetermined threshold, and if it is determined that the reverberation end time is longer, determines whether a foreign object is attached to the ultrasonic sensor or whether an object exists near the ultrasonic sensor based on a predetermined natural frequency and the reverberation frequency. The control device according to claim 1 .

5. The determination circuit further determines whether the difference between the natural frequency and the reverberation frequency is within a predetermined range, and if the difference is within the predetermined range, determines that the object is present near the ultrasonic sensor, and if the difference is beyond the predetermined range, determines that a foreign object is attached to the ultrasonic sensor. The control device according to claim 4.

6. A method implemented by a controller, comprising: The ultrasonic sensor acquires the wave width of the transmitted ultrasonic wave. It is determined whether the wave width of the acquired ultrasonic wave is larger than a threshold value, and if it is determined to be larger, it is determined that an object is present, and if it is equal to or smaller than the threshold value, it is determined that resonance has occurred. Control method.

7. A control method as described in Claim 6, wherein the ultrasonic waves are transmitted by an ultrasonic sensor provided at the front, rear or side of the vehicle.

8. A control method as described in Claim 6, wherein the threshold value is two-fifths of the reverberation end time.

9. Furthermore, the ultrasonic sensor acquires the reverberation end time and the reverberation frequency of the transmitted ultrasonic waves, Furthermore, it is determined whether the reverberation end time of the acquired ultrasonic wave is longer than a predetermined threshold value, If it is determined that the reverberation end time is longer than the predetermined threshold, it is determined whether a foreign object is attached to the ultrasonic sensor or whether an object exists near the ultrasonic sensor based on a predetermined natural frequency and the reverberation frequency. The control method according to claim 6.

10. Furthermore, the ultrasonic sensor acquires the reverberation end time and the reverberation frequency of the transmitted ultrasonic waves, Furthermore, it is determined whether or not the difference between the natural frequency and the reverberation frequency is within a predetermined range; If the difference is within the predetermined range, it is determined that the object is present in the vicinity of the ultrasonic sensor; If the difference exceeds the predetermined range, it is determined that a foreign object is attached to the ultrasonic sensor. The control method according to claim 6.

11. an acquisition step of acquiring a wave width of the ultrasonic wave transmitted by the ultrasonic sensor; a determining step of determining whether or not the wave width of the acquired ultrasonic wave is greater than a threshold value, and determining that an object is present if it is determined to be greater, and determining that resonance has occurred if it is equal to or less than the threshold value; A control program that causes a computer to execute the above.

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