JP5704022B2 - Vehicle approach notification device - Google Patents

Description

  The present invention relates to a vehicle approach notification device that notifies the surroundings that a vehicle is approaching by generating sound from the vehicle.

  In recent years, electric vehicles (EV cars), hybrid cars (HV cars), etc. have structurally low noise, and it is difficult for pedestrians to notice the approach of these vehicles. In order to raise awareness of being near, a vehicle approach notification device that generates a simulated running sound is being installed.

  As such a vehicle approach notification apparatus, there exists a thing shown by patent document 1, for example. In this vehicle approach notification device, a plurality of speakers that sound in each direction outside the vehicle, for example, a speaker that sounds in front of the vehicle on a front bumper and a speaker that sounds in rear of the vehicle on a rear bumper are attached, and the speaker that hits the traveling direction of the vehicle. A method is adopted in which a pedestrian is made to recognize the traveling direction of the vehicle by generating sound.

JP 7-322403 A

  However, the vehicle approach notification device disclosed in Patent Document 1 requires a plurality of speakers and increases the cost. For this reason, there is a case in which only one speaker that sounds in front of the vehicle is attached to the front bumper, and both sound generation in the vehicle front and sound in the vehicle rear are realized by sounding from the speaker even when sounding in the vehicle rear. Many.

  In this case, since the speaker faces the front of the vehicle, the sound pressure toward the rear of the vehicle is reduced, and in particular, a pedestrian who is difficult to see from the driver and is in the vicinity of the back of the vehicle recognizes the movement of the vehicle. There was a problem that the effect would decrease.

  On the other hand, a back buzzer is attached separately from the vehicle approach notification device, and a back warning sound such as a chime sound (for example, pawn, pawn, pawn) is generated at the time of the back so that pedestrians in the vicinity of the back of the vehicle On the other hand, it may be possible to strongly recognize the movement of the vehicle.

  However, the sound generated from the vehicle approach notification device is generated with the frequency component of the same band that is most easily audible on the structure of the human ear, similar to the sound generated from the back buzzer. The sound pressure is unintentionally weakened or strengthened due to sound interference, and the effect of recognizing the start of movement of the vehicle is reduced as a result of being particularly weakened. For this reason, even if the speaker and the back buzzer are provided separately, the effect of causing the pedestrian in the vicinity of the back of the vehicle to accurately recognize the movement of the vehicle cannot be exhibited.

  In view of the above points, the present invention reduces the effect of causing a pedestrian to recognize the movement of a car by sounding an approach notification sound and a back warning sound with a single speaker while reducing the sound pressure of the sound to be sounded. It aims at providing the vehicle approach notification apparatus which can suppress this.

In order to achieve the above object, according to the first aspect of the present invention, while the vehicle is traveling at a low speed, an approach notification sound is generated from the sounding body (3) mounted on the vehicle and the vehicle is in the back state. A vehicle approach warning device that generates a back warning sound from the same sounding body (3), and generates an approach notification sound waveform generating unit for generating an approach notification sound waveform for generating an approach notification sound while the vehicle is traveling at a low speed ( 21a), a back alarm sound waveform generating unit (21b) for generating a back alarm sound waveform for generating a back alarm sound when the vehicle is in the back state, and an approach notification sound waveform generating unit (21a) mixing the mixing unit for generating the approach warning sound waveform and back warning sound waveform generator (21b) is mixed waveform mixes the back alarm sound waveform generated (22), a mixing section (22) to produce Output means (23) for outputting a voltage or current corresponding to the waveform to the sounding body (3) and generating sound corresponding to the mixing waveform from the sounding body (3), and a sound produced by the sounding body (3) A back alarm sound waveform generating section (21b) that corrects the back alarm sound waveform based on the monitoring result of the monitor section (24). A sound correction means is provided.

  Thus, in the vehicle approach notification system, the monitor unit (24) monitors the output level of the sound produced from the sounding body (3), and based on the monitoring result, the back alarm sound waveform generating unit (21b). The generated back alarm sound waveform is corrected. As a result, the back warning sound can be controlled so that the sound pressure level reaches or exceeds a predetermined threshold that can be surely heard by a pedestrian in the vicinity of the back of the vehicle. It is possible to produce pronunciation that can be surely heard by pedestrians in the area. For example, as described in claim 2, the back alarm sound correcting means can correct at least one of the sound pressure and the phase expressed in the back alarm sound waveform.

  In the invention according to claim 3, the approach notification sound waveform generating unit (21a) is provided with an approach notification sound correcting means for correcting the approach notification sound waveform based on the monitoring result of the monitor unit (24). It is characterized by being.

  Thus, in addition to correcting the back alarm sound waveform by the back alarm sound correcting means, the pedestrian whose sound pressure level is in the vicinity of the back of the vehicle by correcting the approach notification sound waveform by the approach notification sound correcting means. Can be set to exceed or exceed a predetermined threshold that is assumed to be reliably heard. For example, as described in claim 4, the approach notification sound correcting means can correct the sound pressure represented by the approach notification sound waveform.

  Further, as described in claim 5, the monitor unit (24) monitors the voltage or current corresponding to the mixing waveform output from the output means (23) to the sound generator (3), thereby producing the sound generator (3). ) Can monitor the output level of the sound produced.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

1 is a block diagram of a vehicle approach notification system including a vehicle approach notification device according to a first embodiment of the present invention. It is the figure which showed the approach notification sound waveform, the back warning sound waveform, and the mixing waveform in the state which is not correcting back alarm sound. It is the figure which showed the approach notification sound waveform, the back warning sound waveform, and the mixing waveform when the sound pressure (amplitude) of the back alarm sound is corrected. It is the figure which showed the approach notification sound waveform, the back warning sound waveform, and the mixing waveform when the sound pressure (amplitude) of the approach notification sound and the back alarm sound and the phase of the back alarm sound are corrected.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
FIG. 1 is a block diagram of a vehicle approach notification system including a vehicle approach notification device according to the present embodiment. With reference to this figure, the vehicle approach notification system including the vehicle approach notification apparatus according to the present embodiment will be described.

  As shown in FIG. 1, the vehicle approach notification system includes a vehicle speed sensor 1 a, a back detection unit 1 b, a vehicle approach notification device 2, and a speaker 3. In the vehicle approach notification system, the vehicle approach notification device 2 generates a sound from the speaker 3 that is a sounding body, thereby reporting the approach of the vehicle to surrounding pedestrians and the like. In this vehicle approach notification system, the speaker 3 is attached to, for example, a front bumper so as to sound forward in the vehicle, but also serves as a back buzzer for sounding backward in the vehicle. Here, the vehicle approach notification device 2 is separated from the speaker 3, but the speaker 3 may be integrated with the vehicle approach notification device 2. Further, the position of the speaker 3 is not limited to the front bumper.

  The vehicle speed sensor 1a outputs a vehicle speed detection signal as a signal indicating the running state of the vehicle. When the detection signal of the vehicle speed sensor 1a is input to the vehicle approach notification device 2, the vehicle approach notification device 2 detects a low-speed traveling state and generates a vehicle approach notification sound corresponding to the vehicle speed during low-speed traveling. The back detection unit 1b inputs a signal indicating that the vehicle is in the back (reverse) state to the microcomputer 21, and indicates, for example, that the back lamp signal or the shift lever is in the reverse direction (R range). A signal is input to the microcomputer 21.

  The vehicle approach notification device 2 includes a microcomputer 21, a mixing unit 22, a power amplifier (hereinafter referred to as AMP) 23, and a speaker output level monitor unit 24.

  The microcomputer 21 includes an approach notification sound waveform generation unit 21a, a back alarm sound waveform generation unit 21b, and the like.

  The approach notification sound waveform generating unit 21a generates an approach notification sound wave for generating an approach notification sound including a pseudo running sound such as a pseudo engine sound or a pseudo motor sound in a low speed traveling state that is between a vehicle start and a predetermined vehicle speed or less. Generate a shape. The approach notification sound waveform generator 21a controls the amplitude of the sound pressure corresponding to the vehicle speed, that is, controls the sound pressure level, and has a memory (not shown) and a digital-analog converter (hereinafter referred to as DAC) or The configuration includes a PWM output device and the like. The memory stores sound control programs and PCM (Pulse Code Modulation) data, that is, audio data converted into data codes and encoded, and corresponds to the vehicle speed indicated by the vehicle speed detection signal An arithmetic expression or a map of the attached sound pressure level is stored. When the vehicle speed detection signal from the vehicle speed sensor 1a is input according to the control program stored in the memory, the approach notification sound waveform generating unit 21a calculates a sound pressure level corresponding to the vehicle speed using an arithmetic expression or a map. The sound pressure level corresponding to the approach notification sound waveform is generated by setting the sound pressure level calculated from the PCM data to a DAC or PWM output device at a predetermined sampling period and outputting it. . For example, by increasing the sound pressure level as the vehicle speed increases, the degree of recognition of the approach of the vehicle to a pedestrian or the like is improved. Further, the approach notification sound is set to about 100 to 4 kHz including a frequency band component (for example, around 2 kHz) that is most easily audible due to the structure of the human ear.

  Further, the approach notification sound waveform generation unit 21 a includes an approach notification sound correction unit that performs amplitude control of sound pressure in accordance with the monitoring result of the speaker output level monitor unit 24. Specifically, as described later, the sound pressure level monitored by the speaker output level monitor unit 24 is set to a predetermined threshold value that is assumed to be surely heard by a pedestrian in the vicinity of the back of the vehicle, or The sound pressure (amplitude) of the approach notification sound is changed by the approach notification sound correcting means so as to exceed that. As a result, a pronunciation that can be reliably heard by a pedestrian in the vicinity of the back of the vehicle is performed.

  The back alarm sound waveform generation unit 21b generates a back alarm sound such as a buzzer sound (such as a beep, a beep, a beep) or a chime sound (for example, a pawn, pawn, pawn) in the back state of the vehicle. Regarding the back warning sound, the frequency band component (around 2 kHz) that is most audible due to the structure of the human ear so that a pedestrian in the vicinity of the back of the vehicle can hear the sound reliably even if it is sounded by the speaker 3 attached to the front bumper. ).

  Further, the back alarm sound waveform generating unit 21b includes a back alarm sound correcting unit that inputs the monitor result of the speaker output level monitor unit 24 and changes the back alarm sound based on the monitor result. Specifically, as described later, the sound pressure level monitored by the speaker output level monitor unit 24 is set to a predetermined threshold value that is assumed to be surely heard by a pedestrian in the vicinity of the back of the vehicle, or In order to exceed this, the back warning sound correcting means changes the sound pressure (amplitude) of the back warning sound or shifts the phase. As a result, a pronunciation that can be reliably heard by a pedestrian in the vicinity of the back of the vehicle is performed.

  The mixing unit 22 mixes the approach notification sound waveform generated by the approach notification sound waveform generating unit 21a and the back alarm sound waveform generated by the back alarm sound waveform generating unit 21b, and a waveform after mixing (hereinafter referred to as a mixing waveform). ) Is output to the AMP 23. That is, the approach notification sound is output in the low-speed traveling state even when the vehicle is in the back state. In such a case, since both the approach notification sound and the back alarm sound are output simultaneously, the mixing waveform obtained by mixing the approach notification sound waveform and the back alarm sound waveform by the mixing unit 22 is output to the AMP 23. I have to. Of course, when the vehicle is traveling at a low speed during forward traveling or not traveling at a low speed in the back state, only one of the approach notification sound and the back alarm sound is output. For this reason, in these cases, the mixing unit 22 outputs either the approach notification sound waveform or the back alarm sound waveform to the AMP 23 as it is.

  The AMP 23 corresponds to output means for applying a voltage corresponding to the output of the microcomputer 21 to the speaker 3 based on the power supply from the power source. The AMP 23 outputs a voltage or current corresponding to the output of the mixing unit 22 to the speaker 3 based on voltage application from a constant voltage source (not shown). The sound pressure generated by the speaker 3 is determined according to the magnitude (amplitude) of the voltage or current output from the AMP 23, and the magnitude of the voltage or current output from the AMP 23 is determined by the output waveform of the mixing unit 22. For this reason, when the output waveforms of the approach notification sound waveform generating unit 21a and the back alarm sound waveform generating unit 21b of the microcomputer 21 are mixed by the mixing unit 22, the voltage or current output by the AMP 23 is changed according to the mixing waveform. It is done. Based on the change in the voltage or current output from the AMP 23, the sound generated from the speaker 3 is changed, and a corresponding approach notification sound or back alarm sound is generated.

  The speaker output level monitor unit 24 monitors the output level of the sound generated from the speaker 3. Here, the speaker output level monitor 24 monitors the voltage or current output from the AMP 23 as corresponding to the output level of the sound produced from the speaker 3. Then, the speaker output level monitoring unit 24 inputs this monitoring result to the back alarm sound waveform generating unit 21b.

  With the configuration as described above, the vehicle approach notification system according to the present embodiment is configured. The vehicle approach notification system configured as described above operates as follows. The operation of the vehicle approach notification system will be described with reference to FIGS.

The vehicle approach notification system generates a simulated running sound from the speaker 3 which is a sounding body during low speed running with low road noise. First, during the period from the time when the vehicle equipped with the vehicle approach notification system is stopped until the vehicle reaches a predetermined vehicle speed, the vehicle approach notification system generates sound because road noise is low. Done. The sound generation from the vehicle approach notification system during low-speed traveling is performed not only when the vehicle is in the forward state but also when it is in the back state. When the approach notification sound is generated in the back state, the back alarm sound is also generated at the same time, and these sound generations are simultaneously performed through one speaker 3.

  At this time, because it is generated with the frequency component in the same band that is most easily audible due to the structure of the human ear, if the approach notification sound and the back warning sound are pronounced simultaneously, the sound pressure may unintentionally weaken due to sound interference. It will become stronger. And as a result of being weakened, the problem that the effect of recognizing the start of movement of the vehicle may be reduced.

  However, in the vehicle approach notification system of the present embodiment, the speaker output level monitor unit 24 monitors the output level of the sound generated from the speaker 3, and based on the monitoring result, the back alarm sound waveform generation unit 21b performs the back alarm. Corrections are made to change the sound pressure and phase of the sound. Specifically, the sound pressure level output from the speaker output level monitor unit 24 is set to a predetermined threshold value that is assumed to be surely heard by a pedestrian in the vicinity of the back of the vehicle or exceeds the predetermined threshold value. Furthermore, the sound pressure (amplitude) of the approach notification sound and the back warning sound is changed, or the phase is shifted. Then, the approaching notification sound waveform and the corrected back alarm sound waveform are mixed by the mixing unit 22, and a sound is generated from the speaker 3 based on the mixing waveform.

  As a result, the approach notification sound and the back alarm sound can be controlled so that the sound pressure level is a predetermined threshold value that is assumed to be surely heard by a pedestrian in the vicinity of the back of the vehicle, or exceeds it. It is possible to ensure that the pedestrian in the vicinity of the back of the vehicle can produce a sound that can be heard reliably.

  FIG. 2 is a diagram showing an approach notification sound waveform, a back alarm sound waveform, and a mixing waveform in a state in which the back alarm sound is not corrected. FIG. 3 is a diagram showing an approach notification sound waveform, a back alarm sound waveform, and a mixing waveform when the sound pressure (amplitude) of the approach notification sound and the back alarm sound is corrected. FIG. 4 is a diagram showing an approach notification sound waveform, a back alarm sound waveform, and a mixing waveform when the sound pressure (amplitude) of the approach notification sound and the back alarm sound and the phase of the back alarm sound are corrected.

  As shown in FIG. 2, when the back alarm sound is not corrected, if the approach notification sound waveform and the back alarm sound waveform are simultaneously generated, the sound interferes, and the amplitude of the mixing waveform (that is, the final sound) It can be seen that the sound pressure of the sound that is output to is weakened.

  On the other hand, as shown in FIG. 3, the sound pressure of the approach notification sound and the sound pressure of the back warning sound are corrected and increased so that the weakened mixing waveform has an amplitude at a desired sound pressure. This makes it possible to adjust the sound pressure of the sound that is finally produced. Further, as shown in FIG. 4, the sound pressure of the approach notification sound and the sound pressure and phase of the back warning sound are corrected, and finally the mixed waveform that has been strengthened becomes an amplitude at a desired sound pressure. It is also possible to adjust the sound pressure of the sound that is pronounced.

  As described above, in the vehicle approach notification system of the present embodiment, the output level of the sound generated from the speaker 3 is monitored by the speaker output level monitor unit 24. Based on the monitoring result, the approach notification sound waveform generating unit 21a corrects the approach notification sound waveform, or the back alarm sound waveform generating unit 21b corrects the back alarm sound waveform. Specifically, the sound pressure of the approach notification sound represented by the approach notification sound waveform and the sound pressure and phase of the back alarm sound represented by the back alarm sound waveform are corrected. As a result, the approach notification sound and the back alarm sound can be controlled so that the sound pressure level is a predetermined threshold value that is assumed to be surely heard by a pedestrian in the vicinity of the back of the vehicle, or exceeds it. It is possible to ensure that the pedestrian in the vicinity of the back of the vehicle can produce a sound that can be heard reliably.

(Other embodiments)
In the above embodiment, the case where the sound pressure of the approach notification sound is set according to the vehicle speed has been described, but the sound pressure of the approach notification sound can be controlled according to the traveling state of the vehicle, not limited to the vehicle speed. it can. For example, the sound pressure of the approach notification sound can be controlled according to the accelerator operation state such as the accelerator opening.

  In the above embodiment, the output level of the sound produced by the speaker 3 is monitored by monitoring the voltage or current corresponding to the mixing waveform output from the speaker output level monitor unit 24 to the speaker 3 that is the sound generator. Like to do. However, the output level itself of the sound produced by the speaker 3 may be detected by the monitor unit 24.

  In the above embodiment, the approach notification sound waveform generating unit 21a corrects the sound pressure of the approach notification sound and the back alarm sound waveform generating unit 21b corrects the sound pressure and phase of the back alarm sound. The back alarm sound may be adjusted to a desired sound pressure by correcting the back alarm sound by the alarm sound waveform generating unit 21b. For example, at least one of the sound pressure and the phase of the back alarm sound may be corrected.

DESCRIPTION OF SYMBOLS 1a Vehicle speed sensor 1b Back | bag detection part 2 Vehicle approach warning apparatus 3 Speaker 21 Microcomputer 21a Approach notification sound waveform generation part 21b Back warning sound wave generation part 22 Mixing part 23 AMP
24 Speaker output level monitor

Claims (5)

While the vehicle is traveling at low speed, the approaching sound is sounded from the sounding body (3) mounted on the vehicle, and the vehicle approaching sounding the back warning sound from the same sounding body (3) when the vehicle is in the back state. An alarm device,
An approach notification sound waveform generating unit (21a) for generating an approach notification sound waveform for generating the approach notification sound during low-speed traveling of the vehicle;
A back alarm sound waveform generator (21b) for generating a back alarm sound waveform for generating the back alarm sound when the vehicle is in a back state;
Mixing unit for generating a mixing waveform mixes the said back alarm sound waveform in which the approach warning sound waveform generator (21a) the approach warning sound waveform and said back alarm sound waveform generator generated there is (21b) to produce (22 )When,
Output means (23) for outputting a voltage or current corresponding to the mixing waveform generated by the mixing unit (22) to the sounding body (3) and generating sound corresponding to the mixing waveform from the sounding body (3). When,
A monitor unit (24) for monitoring the output level of the sound produced by the sounding body (3),
The back alarm sound waveform generation unit (21b) is provided with back alarm sound correcting means for correcting the back alarm sound waveform based on the monitoring result of the monitor unit (24). Vehicle approach notification device.   2. The vehicle approach notification device according to claim 1, wherein the back warning sound correcting unit corrects at least one of a sound pressure and a phase expressed in the back warning sound waveform.   The approach notification sound waveform generation unit (21a) includes an approach notification sound correction unit that corrects the access notification sound waveform based on the monitoring result of the monitor unit (24). The vehicle approach notification device according to claim 1 or 2.   The vehicle approach notification device according to claim 3, wherein the approach notification sound correcting unit corrects a sound pressure expressed in the approach notification sound waveform.   The monitor unit (24) monitors the voltage or current corresponding to the mixing waveform output to the sounding body (3) by the output means (23), thereby generating sound generated by the sounding body (3). The vehicle approach notification device according to any one of claims 1 to 4, wherein the output level of the vehicle is monitored.

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