JP2011207392A - Sound producing apparatus for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound producing apparatus for a vehicle suppressing unnecessary generation of the noise by the sound producing apparatus.SOLUTION: The sound producing apparatus for a vehicle notifying outside the vehicle of a vehicle's approach includes: an original tone generating unit 2 generating an original tone of an approaching sound for recognition of the vehicle's approach; a modulation tone generating unit 4 generating a modulation tone from the original tone; a sound pressure setting unit 5 setting a sound pressure of the approaching sound of the modulation tone; a speaker 6 producing outside the vehicle the approaching sound of the modulation tone with the set sound pressure; an image processing unit 7 detecting the change of behavior of the obstacle outside the vehicle; and a control unit 8 controlling at least either one of the modulation tone generating unit 4 and the sound pressure setting unit 5 so as to change the approaching sound before and after the change of behavior of the obstacle.

Description

  The present invention relates to a vehicular sound generation device, and more particularly to a vehicular sound generation device that is suitable for being mounted on a low-noise vehicle such as an electric vehicle and a hybrid vehicle and that notifies the vehicle approach to the outside of the vehicle.

  A low-noise vehicle has less noise when traveling than a conventional automobile, and thus a pedestrian may not notice the approach of the vehicle. For this reason, in order to make a pedestrian or a person riding a bicycle notice the approach of the vehicle, it has been proposed to generate a running pseudo sound from the vehicle.

  The following Patent Document 1 discloses a technique for generating a pseudo sound of tire noise or engine idling sound. Patent Document 2 below discloses a technique for generating a pseudo sound according to an area where a vehicle is traveling.

JP 2009-40318 A JP 2005-253236 A

By the way, these pseudo sounds are nothing but noise for the surroundings of the vehicle, and also reduce the advantage of the low noise vehicle such as high quietness.
Moreover, when the pedestrian has already noticed the approach of a vehicle, the necessity to generate | occur | produce a pseudo sound and alert | report vehicle approach reduces.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle sounding device that can suppress unnecessary noise generation by the sounding device.

  In order to achieve the above object, a vehicular sound generation device according to the present invention is a vehicular sound generation device that notifies the outside of a vehicle of the approach of the vehicle, and generates an original tone color of an approaching sound for recalling the approach of the vehicle. An original tone color generation means, a modulation tone color generation means for generating a modulation tone color from the original tone color, a sound pressure setting means for setting the sound generation sound pressure of the approaching sound of the modulation tone, and the set sound generation sound pressure to the outside of the vehicle A sounding means for generating an approaching sound of a modulated tone, an obstacle detecting means for detecting a behavior change of an obstacle outside the vehicle, a modulation tone generating means and a sound so as to change the approaching sound before and after the behavior change of the obstacle And control means for controlling at least one of the pressure setting means.

  According to the present invention configured as described above, the behavior of an obstacle including a pedestrian or a person riding a bicycle can be confirmed by looking back at the vehicle, for example, or moved to the edge of the road to avoid the vehicle. The approaching sound after the change is changed from the approaching sound before the behavior change. Thereby, according to this invention, suppression of the unnecessary noise generation by a sounding device can be aimed at.

  Further, as a secondary effect, it is possible to notify the obstacle by changing the approach sound that the sound generator of the vehicle has recognized a behavior such as a confirmation action or avoidance action of an obstacle such as a pedestrian. I can expect.

In the present invention, it is preferable that the control unit controls at least one of the modulation tone generation unit and the sound pressure setting unit so as to change the approaching sound discontinuously before and after the behavior change of the obstacle.
If the approaching sound is changed discontinuously by changing the tone of the approaching sound abruptly or by changing the sound pressure of the approaching sound abruptly, a person who is an obstacle is likely to notice the change of the approaching sound. In addition, other humans around the same can easily notice the approaching sound due to the discontinuous change of the approaching sound.

In the present invention, it is preferable that the control unit controls the sound pressure setting unit so that the sound pressure of the approaching sound after the behavior change of the obstacle is lower than the sound pressure of the approaching sound before the behavior change. .
After the behavior is changed by the confirmation action or the avoidance action of the vehicle, it is not necessary to be aware of the approach of the vehicle again because the obstacle is usually already aware of the approach of the vehicle. Therefore, by reducing the sound pressure of the approaching sound after the behavior change, it is possible to suppress unnecessary noise generation by the sound generator.

  In the present invention, it is preferable that the control means has an infinite scale in which the fundamental frequency and the frequency component of the harmonic string of the fundamental frequency repeatedly transition at a predetermined transition speed before changing the behavior of the obstacle. The modulation tone generation unit is controlled so that a modulation tone is generated and a modulation tone whose transition speed is reduced or the transition is stopped is generated after the behavior change of the obstacle.

  The infinite scale has the effect of making a person who hears this an illusion of a continuous increase in frequency while substantially maintaining the frequency characteristics of the original timbre. For this reason, the approach of the vehicle can be felt more strongly. And after changing a behavior by the confirmation action and avoidance action of a vehicle, since the obstacle has already noticed the approach of the vehicle normally, it is not necessary to be aware of the approach of the vehicle again. Therefore, by reducing the transition speed of the infinite scale or stopping the transition, unnecessary noise generation by the sound generator can be suppressed.

In the present invention, it is preferable that the control means controls the sound pressure setting means so that the sound pressure of the approaching sound is gradually increased until a behavior change due to an obstacle is detected.
As described above, by gradually increasing the sound pressure of the approaching sound, it is possible to easily recognize the obstacle approaching the vehicle.

  In the present invention, preferably, the behavior change of the obstacle includes a vehicle confirmation action by the obstacle and a vehicle avoidance action by the obstacle, and the control means approaches before and after the vehicle confirmation action by the obstacle. At least one of the modulated tone generation means and the sound pressure setting means is controlled so as to change the sound and further change the approaching sound before and after the vehicle avoidance action by the obstacle.

As described above, by changing the approach sound according to the vehicle confirmation action and the vehicle avoidance action by the obstacle, it is possible to suppress unnecessary noise generation by the sound producing device.
Also, as a secondary effect, it is expected that the sound generator of the vehicle will notify the obstacle by recognizing that the behavior change of the confirmation action and the avoidance action due to the obstacle is changed by changing the approach sound. it can.

In the present invention, it is preferable to further include a memory that stores the original tone color generation data of the approaching sound in association with the running state of the vehicle, and the original tone color generating means generates the original tone color corresponding to the running state of the vehicle. Data is read and an original tone color is generated.
Thereby, the original tone color according to the running state of the vehicle is generated. As a result, when the approaching sound is recalled by the approaching sound, it can be expected that the running state of the vehicle such as the speed and acceleration of the vehicle is also recalled at the same time.

  According to the vehicle sound producing device of the present invention, it is possible to suppress unnecessary noise generation by the sound producing device.

It is a block diagram which shows the structure of the vehicle sound generator by 1st Embodiment of this invention. It is a top view which shows typically arrangement | positioning of the sensor in the vehicle by 1st Embodiment of this invention. (A) is a graph which shows the frequency distribution of the sound pressure of the original tone color in 1st Embodiment, (B) is a graph which shows the frequency characteristic of the gain of an initial stage modulation filter, (C) is a change. It is a graph which shows the frequency characteristic of the gain of a later modulation filter, (D) is a graph which shows the frequency distribution of the sound pressure of a modulation | alteration timbre. It is a flowchart which shows the action | operation of the sound generator for vehicles by 1st Embodiment of this invention. It is a graph which shows the time change of the sound pressure of approaching sound. (A) is a graph which shows the frequency distribution of the sound pressure of the original tone color in 2nd Embodiment, (B) is a graph which shows the frequency characteristic of the gain of an initial stage modulation filter, (C) is a change. It is a graph which shows the frequency characteristic of the gain of a later modulation filter, (D) is a graph which shows the frequency distribution of the sound pressure of a modulation | alteration timbre.

Hereinafter, embodiments of a sound generator for a vehicle according to the present invention will be described with reference to the accompanying drawings.
First, with reference to FIG. 1, the structure of the vehicle sound generator according to the embodiment of the present invention will be described. FIG. 1 is a block diagram illustrating a configuration of a vehicle sound producing device according to an embodiment.

  As shown in FIG. 1, the sound generator for a vehicle according to the embodiment generates an original condition color of an approaching sound for reminding the approach of the vehicle and the operating condition determination unit 1 in order to notify the approach of the vehicle to the outside of the vehicle. An original tone color generation unit 2, a memory 3 that stores data for generating original tone colors, a modulation tone generation unit 4 that generates a modulation tone from the original tone color, and a sound pressure setting that sets a sound generation sound pressure of an approaching sound of the modulation tone Unit 5, speaker 6 as sounding means for generating an approaching sound of modulated tone to the outside of the vehicle with the set sounding sound pressure, and image processing unit as obstacle detecting means for detecting a change in behavior of an obstacle outside the vehicle 7 and a control unit 8 that controls at least one of the modulation tone generation unit 4 and the sound pressure setting unit 5 so as to change the approaching sound before and after the behavior change of the obstacle.

  The operating condition determination unit 1, the original tone color generation unit 2, the modulated tone color generation unit 4, the sound pressure setting unit 5, the image processing unit 7, and the control unit 8 have, for example, processing functions in an in-vehicle ECU (electric control unit). Equivalent to. These processing functions may be realized by executing a predetermined program in a computer, or may be realized by a microchip.

The operating condition determination unit 1 determines whether or not a condition for generating an approaching sound is satisfied. As the determination condition, the traveling vehicle speed detected by the vehicle speed sensor 9 is not more than a predetermined reference vehicle speed, for example, (0 <vehicle speed ≦ 20 km / h).
The vehicle speed sensor 9 is provided in an engine room in front of the vehicle C as shown in FIG. FIG. 2 is a schematic plan view of the vehicle.

Further, as another determination condition, there is a case where the horn switch (horn SW) 10 is operated even when the vehicle is stopped. This is because it is desirable for the determination condition to make a person around the vehicle aware that the vehicle has started when starting the stopped electric vehicle. Therefore, the approaching sound generated by the sounding device can be used as a warning means that is gentler than that of sounding a horn.
As shown in FIG. 2, the horn switch 10 is provided on the steering wheel of the driver's seat of the vehicle.

The original tone color generation unit 2 reads the original tone color generation data corresponding to the traveling state of the vehicle from the memory 3 and generates an original tone color. The memory 3 stores original tone color generation data in association with the traveling state of the vehicle. Examples of the running state of the vehicle include the vehicle speed detected by the vehicle speed sensor 9, the engine speed (or engine output) detected by the engine rotation sensor 11, and the accelerator opening detected by the accelerator opening sensor 12. .
The engine rotation sensor 11 and the accelerator opening sensor 12 are also provided in the engine room in front of the vehicle C as shown in FIG.

  In the present embodiment, the memory 3 stores original tone color generation data in association with at least one of the vehicle speed, the engine speed, and the accelerator opening. Therefore, the original tone color generation unit 2 reads the original tone color generation data associated with at least one of the vehicle speed, the engine speed, and the accelerator opening, and generates an original tone color corresponding to the vehicle speed or the like.

FIG. 3A schematically shows the generated original tone color graph. The horizontal axis of this graph represents frequency, and the vertical axis represents sound pressure. A curve I in the graph indicates a frequency characteristic of the sound pressure of the original tone color.
The original tone color generation data may be generated using recorded data of tire noise and engine sound of a vehicle that is actually running, or may be generated as a synthesized sound.

The modulated tone color generation unit 4 generates a modulated tone color from the original tone color. For this purpose, the modulation tone generation unit 4 has a modulation filter function.
FIG. 3B schematically shows a graph showing the characteristics of the initialized modulation filter. The horizontal axis of this graph represents frequency, and the vertical axis represents gain (gain). Line II in the graph represents the frequency characteristic of the gain of the initialized modulation filter. As shown by the line II, this initialized modulation filter provides a constant gain g1 regardless of the frequency. For example, the gain g1 = 1.0 dB.

FIG. 3C schematically shows a graph showing the characteristics of the modulation filter after the change. The horizontal axis of this graph represents frequency, and the vertical axis represents gain (gain). A curve III in the graph shows the frequency characteristic of the gain of the modulation filter after the change. As shown in the curve III, modulated filter after the change is a high-pass filter, the frequency component higher than a predetermined threshold frequency f _c, greater than the gain g ₃ to be applied to the frequency components below the threshold frequency f _c A gain g ₂ is selectively given. For example, the gain g ₂ = 0.0 dB and the gain g ₃ = −3 dB are preferable.

  Then, the modulated tone color generation unit 4 generates a modulated tone color from the original tone color using the initialized modulation filter or the modified modulation filter.

  FIG. 3D schematically shows a modulation tone color graph. The horizontal axis of the graph represents frequency, and the vertical axis represents sound pressure. A solid line IV in the graph indicates the frequency characteristic of the sound pressure of the modulated timbre generated by multiplying the original timbre of FIG. 3A by the initialized modulation filter of FIG. 3B. A broken line V in the graph indicates a frequency characteristic of the sound pressure of the modulated timbre generated by multiplying the original timbre of FIG. 3A by the modified modulation filter of FIG. Furthermore, the alternate long and short dash line VI in the graph is generated by multiplying the original tone color in FIG. 3A by a modulation filter with the gains g2 and g3 of the modulation filter after the change in FIG. In addition, the frequency characteristics of the sound pressure of the modulated timbre are shown.

As indicated by the solid line IV, when the initialized modulation filter of FIG. 3B is used, a modulation tone of the original tone color is generated substantially. Further, as shown by the dashed line V, when using a modulation filter after the change of FIG. 3 (C), the modulation tone sound pressure in the low frequency range than the threshold frequency f _c is suppressed is generated. Furthermore, as shown by the alternate long and short dash line VI, when the modulation filter with the gains g2 and g3 of the modulation filter after the change shown in FIG. 3C is used, a modulation tone that further suppresses the entire sound pressure is generated. Is done.

The sound pressure setting unit 5 sets the sound generation sound pressure of the approaching sound of the modulated tone color. In setting the sound generation sound pressure, it is desirable to set a sound pressure slightly higher than the sound pressure of the surrounding environment.
Note that the sound pressure of the surrounding environment of the vehicle is measured by the microphone 13 as the ambient environment sound pressure measuring means. As shown in FIG. 2, the microphone 13 is provided immediately before the windshield of the vehicle and near the center in the vehicle width direction.

Further, when the vehicle headlight is on, the pedestrian usually notices the approach of the vehicle by the light of the headlight. In such a case, it is not necessary to generate a loud approaching sound, and a small approaching sound is sufficient. Therefore, when the image captured by the camera 14 is processed by the image processing unit 7 and the surrounding environment is determined to be nighttime and the headlight of the vehicle is turned on, the set sound pressure is set to daytime. It is desirable to make it lower than the set sound pressure.
As shown in FIG. 2, the camera 14 is provided at the center in the vehicle width direction inside the windshield and near the ceiling of the passenger compartment.

  In addition, when there is a vehicle that produces an approaching sound near the host vehicle, a howling phenomenon may occur if the sound pressure is set slightly higher than the approaching sound of the opponent vehicle. . Therefore, it is desirable to set an appropriate upper limit value when setting the sound pressure.

From the speaker 6, an approaching sound of a modulated tone is generated outside the vehicle with the set sounding sound pressure. By sounding the approach of the modulated timbre in this way, it is possible to generate a sound that easily recalls the approach of the vehicle while suppressing noise from the sound producing device.
In addition, the speaker 6 is provided in the vehicle width direction center vicinity of the vehicle head, as shown in FIG.

  The image processing unit 7 not only determines whether the cyclic environment is day or night, but also extracts obstacles such as pedestrians and bicycles from the image captured by the camera 14. Furthermore, the image processing unit 7 also detects a change in the behavior of the obstacle as an obstacle detection means. Examples of changes in the behavior of obstacles include pedestrians (including pedestrians and people riding bicycles) looking back and confirming vehicles, and evacuation behaviors when pedestrians avoid vehicles, etc. Is mentioned.

The vehicle confirmation behavior may be detected as the vehicle confirmation behavior, for example, when the face direction of a pedestrian or the like is rotated 60 ° or more in the vehicle direction. The vehicle avoidance behavior may be detected as the vehicle avoidance behavior, for example, when a pedestrian or the like leaves the vehicle or when the approach speed of the pedestrian to the vehicle is reduced. Specifically, in the past 5 seconds, the state where the time derivative dL / dt ≧ 0 of the distance L from the vehicle to the obstacle or the second derivative dL / dt ² ≧ 0 continues for 0.5 seconds or more. Therefore, it may be detected as a vehicle avoidance action.

Then, the control unit 8 controls at least one of the modulation tone generation unit 4 and the sound pressure setting unit 5 so as to change the approaching sound before and after the behavior change of the obstacle.
In the first embodiment, the control unit 8 controls the modulation tone generation unit 4 and uses the initialized modulation filter of FIG. 3B before the image processing unit 7 detects the behavior change. 3D, a modulated tone color that is substantially the original tone color indicated by a solid line IV is generated.

On the other hand, after the image processing unit 7 detects the behavior change, the control unit 8 controls the modulation tone generation unit 4 to use the modified modulation filter of FIG. ) modulation tone bass sound pressure than the threshold frequency f _c shown by the broken line curve V is suppressed is generated. Thereby, after a behavior change, the noise by an approach sound is suppressed.

  When the control unit 8 controls the modulation tone generation unit 4 to change the approaching sound before and after detecting the behavior change, the control unit 8 may change the approaching sound discontinuously by switching the modulation filter.

  The control unit 8 may control the sound pressure setting unit 5 to lower the sound pressure of the approaching sound after the behavior change of the obstacle is lower than the sound pressure of the approaching sound before the behavior change. Even in such a case, the sound pressure of the approaching sound may be rapidly reduced to change the approaching sound discontinuously. The discontinuous change in the approaching sound makes it easier for a human being who is an obstacle to notice the change in the approaching sound. In addition, it is expected that surrounding humans other than the obstacles can easily recognize the approaching sound due to the discontinuous change of the approaching sound.

  The control unit 8 may control only the modulation tone generation unit 4, may control only the sound pressure setting unit 5, or controls both the modulation tone generation unit 4 and the sound pressure setting unit 5. May be.

Next, the operation of the vehicle sound producing device according to the embodiment will be described with reference to the flowchart of FIG.
First, the operating condition determination unit 1 acquires the vehicle speed from the vehicle speed sensor 9 (S1).

  Next, the operating condition determination unit 1 determines whether or not the vehicle speed V satisfies a condition of 0 <V ≦ 20 km / h (S2). When this condition is not satisfied (in the case of “NO” in S2), the operating condition determination unit 1 determines whether or not the horn switch (horn SW) is operated (ON) (S3).

  When the vehicle speed satisfies the above condition (in the case of “YES” in S2), or when the horn switch is operated (in the case of “YES” in S3), the original tone color generation unit 2 performs vehicle running state data. Is acquired (S4). The running state data includes vehicle speed, engine speed, and accelerator opening.

  Next, the original tone color generation unit 2 reads out the original tone color generation data corresponding to the acquired traveling state, and generates the original tone color shown in FIG. 3A (S5).

  Next, ambient environment data captured by the camera 14 and processed by the image processing unit 7 and ambient environment sound pressure data detected by the microphone 13 are acquired (S6).

  When the image processing unit 7 does not detect a vehicle confirmation action by a pedestrian or the like as a behavior change of an obstacle outside the vehicle (in the case of “NO” in S7), the control unit 8 causes the modulation tone generation unit 4 to The initialized first modulation filter shown in FIG. 3B is selected (S8).

  On the other hand, when the image processing unit 7 detects a vehicle confirmation action by a pedestrian or the like as a behavior change of an obstacle outside the vehicle (in the case of “YES” in S7), the control unit 8 causes the modulation tone generation unit 4 to The changed first modulation filter in FIG. 3C is selected (S9).

  Subsequently, when the image processing unit 7 does not detect a vehicle avoidance action by a pedestrian or the like as a behavior change of an obstacle outside the vehicle (in the case of “NO” in S10), the control unit 8 causes the modulation tone generation unit 4 to Then, the initialized second modulation filter in FIG. 3A is selected (S11).

  On the other hand, when the image processing unit 7 detects a vehicle avoidance action by a pedestrian or the like as a behavior change of an obstacle outside the vehicle (in the case of “YES” in S10), the control unit 8 causes the modulation tone generation unit 4 to The one obtained by reducing the gain of the first modulation filter after the change in FIG. 3C is selected as the second modulation filter after the change (S12).

Next, the modulated tone color generation unit 4 generates a modulated tone color from the original tone color using the selected first and second modulation filters (S13).
Until the vehicle confirmation action by a pedestrian or the like is detected, the initialized first modulation filter shown in FIG. 3B is the same as the initialized second modulation filter shown in FIG. 3B. Are used to generate a modulated timbre substantially the same as the original timbre shown by the solid line IV in FIG.

  In addition, when the vehicle confirmation action by the pedestrian or the like is detected, but the vehicle avoidance hardness is not detected, the changed first modulation filter shown in FIG. 3C and the initial shown in FIG. The second modulation filter is used in combination. As a result, a modulated tone color in which the low frequency range is attenuated, which is indicated by a broken line V in FIG.

  Furthermore, after a vehicle confirmation action by a pedestrian or the like is detected and further a vehicle avoidance action is detected, the changed first modulation filter shown in FIG. 3C and the gain shown in FIG. The changed second modulation filter is used in combination with the lowered changed second modulation filter, and the changed second modulation filter having a small gain is selected. . As a result, a modulated timbre whose overall gain is suppressed as compared with the broken line V, which is indicated by a one-dot chain line VI in FIG.

Next, the sound pressure setting unit 5 sets the sound generation sound pressure of the approaching sound of the modulated timbre (S14).
Here, the sound pressure setting unit 5 may set a sound pressure that is slightly higher than the ambient environmental sound pressure measured by the microphone 13. Further, when it is determined that it is nighttime by the image processing unit 7 that has processed the image captured by the camera 14 and the headlight is turned on, it is preferable to set a lower sound pressure setting.

Next, the speaker 6 generates an approaching sound of a modulated tone color outside the vehicle with the set sound generation sound pressure (S15).
In this way, unnecessary noise generation by the sound producing device can be suppressed.

  In the flowchart shown in FIG. 4, an example in which the behavior change of the obstacle is detected in two stages of the vehicle confirmation action and the vehicle avoidance action will be described. It is good also as one step which detects at least one of vehicle check action and vehicle avoidance action.

  Further, in the flowchart shown in FIG. 4, when the vehicle avoidance action by a pedestrian or the like is not detected (in the case of “NO” in S10), the initialized second modulation filter shown in FIG. However, instead of initializing the second modulation filter, the gain g1 in FIG. 3B may be slightly increased. Thus, each time the flowchart shown in FIG. 4 makes one rotation, the sound pressure of the approaching sound may increase until the pedestrian or the like takes an avoidance action.

  In FIG. 5, the time change of the sound pressure of approaching sound is shown by the line I. FIG. In the example shown in FIG. 5, the sound pressure of the approaching sound gradually increases with time until time t1, and the vehicle avoidance action is detected and the sound pressure is suddenly reduced at time t1. In this way, gradually increasing the sound pressure of the approaching sound makes it easier to notice the approach of the vehicle to the obstacle, and also makes the approaching sound noticeable by rapidly reducing the sound pressure of the approaching sound. Can be expected.

  In FIG. 5, the gain is continuously increased as indicated by line I, but the gain may be increased stepwise. Further, the control unit 8 can control the sound pressure setting unit 5 instead of the modulation tone generation unit 4 to change the sound pressure of the approaching sound as shown in FIG.

Next, a vehicle sound producing device according to a second embodiment of the present invention will be described with reference to FIG.
The configuration of the vehicular sound producing device according to the second embodiment is the same as that of the first embodiment shown in FIG. In the second embodiment, as shown by a curve I in FIG. 6A, the original tone color similar to the original tone color used in the first embodiment is used. However, in the second embodiment, the modulation filter used in the modulation tone generation unit 4 is different from that in the first embodiment. Therefore, the modulation filter will be described in detail.

  In the second embodiment, the control unit 8 repeats the fundamental frequency f0 and the frequencies f1, f2,... Of the harmonic sequence of the fundamental frequency f0 in the modulated tone color generation unit 4 before changing the behavior of the obstacle. A modulation tone of an infinite scale that transitions to the side at a predetermined transition speed is generated.

  FIG. 6B schematically shows a graph showing the characteristics of the modulated filter that has been initialized. The horizontal axis of this graph represents frequency, and the vertical axis represents gain (gain). Line II in the graph indicates the frequency characteristic of the gain of the comb filter function 4a. As shown by line II, in this comb filter function 4a, a high gain g1 is given to some frequency components of f1, f2,..., F6 of the harmonic sequence of the fundamental frequency f0 at a certain time, and the others A low gain g2 is given to the frequency component. For example, the gain g1 = 1.2 dB and the gain g2 = 0.0 dB may be used.

Then, as indicated by arrows in FIG. 6B, the gains are changed according to the envelope E while the frequencies of these fundamental frequencies f0 and their harmonics sequences f1 to f6 transition to the high frequency side over time. Yes. By using this initialized modulation filter, an infinite scale effect can be generated.
Note that the shape of the envelope E is not limited to a trapezoid, and may be, for example, a bell shape with a widening end.

  FIG. 6C schematically shows a graph showing the characteristics of the modulation filter after the change. The horizontal axis of this graph represents frequency, and the vertical axis represents gain (gain). Line III in the graph indicates the frequency characteristic of the gain of the modulation filter after the change. As shown by the line III, in the modulation filter after the change, a constant gain g4 is given regardless of the frequency. For example, the gain g4 = 0.0 dB. In the modulation filter after the change in FIG. 6C, the timbre does not transition to the high pitch side, and the infinite scale effect does not occur.

  And the control part 8 makes the modulation | alteration timbre production | generation part 4 produce | generate the modulation | alteration timbre by which the transition stopped after the obstacle behavior change so that an approach sound may be changed before and after the behavior change of an obstacle.

  In the second embodiment, the control unit 8 controls the modulation tone generation unit 4 before the image processing unit 7 detects the behavior change, and uses the initialized modulation filter of FIG. A modulated tone is generated.

  FIG. 6D schematically shows a modulation tone color graph. The horizontal axis of the graph represents frequency, and the vertical axis represents sound pressure. A curve IV in the graph indicates a frequency characteristic of the sound pressure of the modulated timbre before detecting a behavior change of a pedestrian or the like. As shown by the curve IV, the modulation tone before the behavior change is detected is based on the original tone shown in FIG. 6A, and the sound pressure peaks p0 to p6 are set at the fundamental frequency f0 and the frequencies f1 to f6 of the harmonic sequence. Have each. These sound pressure peaks p0 to p6 transition to the high frequency side as the fundamental frequency and the frequency of the harmonic sequence thereof transition to the high frequency side. Thereby, the approaching sound of the modulated timbre can produce an infinite scale effect that makes the human who hears this illusion of a continuous increase in frequency.

  The sound pressure at each peak gradually increases in the low frequency region and gradually decreases in the high frequency region as the fundamental frequency transitions to the high frequency side. As a result, the fundamental frequency having a high gain and the frequency components of the harmonic sequence thereof fade in from the low frequency side, and fade out as the frequency component transitions to the high frequency side. Thereby, an infinite scale effect can be produced without a sense of incongruity.

  On the other hand, after the image processing unit 7 detects the behavior change, the control unit 8 controls the modulation tone generation unit 4 to use the modified modulation filter of FIG. ) Generates a modulated tone color substantially the same as the original tone color indicated by a broken line V in FIG. In this modulated tone, the fundamental frequency does not transit on the high frequency side and does not generate an infinite scale.

  In this way, the infinite scale has the effect of making a person who hears this an illusion of a continuous increase in frequency while substantially maintaining the frequency characteristics of the original tone color. For this reason, the approach of the vehicle can be felt more strongly. Then, after the behavior change, by stopping the transition of the infinite scale, it is possible to suppress unnecessary noise generation by the sound generator. Further, by switching the modulation filter used in the modulation tone generation 4, the timbre of the approaching sound can be rapidly changed before and after the behavior change.

  Note that the modulation filter to be selected after the behavior change is not the one shown in FIG. 6 (C), but the one in which the transition frequency of the peak frequency of the initialized modulation filter shown in FIG. 6 (B) is reduced is used. Also good. By switching the modulation filter before and after the behavior detection, the transition speed of the infinite scale can be rapidly reduced.

  In the above-mentioned embodiment, although the example which comprised this invention on the specific conditions was demonstrated, this invention can perform a various change and combination, and is not limited to this. For example, in the above-described embodiment, an example has been described in which a modulated tone is generated by giving a high gain to a harmonic string for one fundamental frequency. However, in the present invention, the fundamental frequency is not limited to one, and the phases are different. A modulated timbre may be generated using a high gain for the harmonic series of each of the plurality of fundamental frequencies.

  In the above-described embodiment, the example in which the correction filter function has the frequency characteristic of the gain of the trapezoidal waveform has been described. However, in the present invention, the characteristic of the correction filter function is not limited to this. You may give the frequency characteristic of the gain used as a waveform.

The sound generating device for a vehicle according to the present invention can be used by being mounted on a vehicle having low noise during traveling such as an electric vehicle and a hybrid vehicle.
By the way, the fact that the timbre and sound pressure of the approaching sound change due to the behavior change of an obstacle such as a pedestrian means that the pedestrian or the like can actively change the approaching sound by his / her own action. Furthermore, when the approaching sound changes, the pedestrian or the like can know that the vehicle side has detected the behavior of the pedestrian or the like. Therefore, the sound generator for vehicles of the present invention can also be used as one of means for realizing mutual communication between the vehicle and pedestrians. By using the vehicle sound producing device of the present invention, pedestrians and the like can act on the vehicle side by their own actions, so the pedestrians and the like receive unilateral noise from the vehicle and feel anxiety and dissatisfaction. The situation to obtain can be improved.

DESCRIPTION OF SYMBOLS 1 Operation condition determination part 2 Original tone color production | generation part 3 Memory 4 Tone modulation part 5 Sound generation sound pressure setting part 6 Speaker 7 Image processing part 9 Vehicle speed sensor 10 Horn switch 11 Engine rotation sensor 12 Accelerator opening degree sensor 13 Camera 14 Microphone 100 ECU

Claims (7)

A vehicular sound generation device that notifies the vehicle approach to the outside of the vehicle,
An original tone color generating means for generating an original tone color of an approaching sound for recalling the approach of a vehicle;
Modulation tone generation means for generating a modulation tone from the original tone color;
Sound pressure setting means for setting the sound pressure of the approaching sound of the modulated tone,
A sounding means for generating an approaching sound of the above-mentioned modulated tone outside the vehicle with a set sounding sound pressure;
Obstacle detection means for detecting behavior changes of obstacles outside the vehicle;
A vehicle sound generator comprising: control means for controlling at least one of the modulated tone color generation means and the sound pressure setting means so as to change the approaching sound before and after the behavior change of the obstacle.   2. The control unit according to claim 1, wherein the control unit controls at least one of the modulation tone generation unit and the sound pressure setting unit so that the approaching sound changes discontinuously before and after the behavior change of the obstacle. The vehicle sound generator as described.   The control means controls the sound pressure setting means so as to lower the sound pressure of the approaching sound after the behavior change of the obstacle to be lower than the sound pressure of the approaching sound before the behavior change, The sound generator for a vehicle according to claim 1 or 2.   The control means generates a modulation tone of an infinite scale in which the fundamental frequency and the frequency component of the harmonic sequence of the fundamental frequency repeatedly transition to the high pitch side at a predetermined transition speed before the behavior change of the obstacle, and 4. The modulated tone color generation unit is controlled so that a modulated tone color in which the transition speed is reduced or the transition is stopped is generated after the behavior change of the obstacle. The vehicle sound producing device according to claim 1.   The control means controls the sound pressure setting means so that the sound pressure of the approaching sound is gradually increased until a behavior change due to the obstacle is detected. The vehicle sound producing device according to one item. The behavior change of the obstacle includes a vehicle confirmation action by the obstacle and a vehicle avoidance action by the obstacle.
The control means changes the approach sound before and after the vehicle confirmation action by the obstacle and further changes the approach sound before and after the vehicle avoidance action by the obstacle. 6. The vehicle sounding device according to claim 1, wherein at least one of the setting means is controlled. It further has a memory that stores the original sound color generation data of the approaching sound in association with the running state of the vehicle,
The vehicle sound generation according to any one of claims 1 to 6, wherein the original sound color generation means reads the original sound color generation data corresponding to the running state of the vehicle and generates the original sound color. apparatus.

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