JP5451905B2 - Notification sound control device for electric vehicle and notification sound generator - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a notification sound generator for an electric mobile body that generates a notification sound for notifying a pedestrian or the like of a highly quiet electric mobile body such as a hybrid vehicle or an electric vehicle.

  In recent years, following the development and practical use of electric bicycles and electric carts, vehicles such as electric motorcycles and electric automobiles are being electrified. Specifically, instead of a vehicle using an internal combustion engine as a power source, charging is performed by a hybrid vehicle using a gasoline engine and an electric motor as a power source, or a charger installed at a household power source or a gasoline station or power supply station. Electric vehicles powered by electric motors powered by batteries, or fuel cell vehicles that run while generating power from fuel cells that use hydrogen gas or the like as fuel, are being developed sequentially. Some of them have already been put into practical use and are beginning to spread.

  Gasoline vehicles, diesel vehicles, motorcycles, etc. that use conventional internal combustion engines as power sources (hereinafter referred to as `` conventional vehicles, etc. '') emit engine sounds and exhaust sounds emitted by the power sources themselves, as well as roads that are running. Since noise or the like is generated, a pedestrian walking in the city or a person riding a bicycle can recognize the approach of the vehicle by the engine sound or exhaust sound of the automobile. However, in the case of a hybrid vehicle, when traveling at a low speed, the driving mode is driven mainly by an electric motor, not by an engine, so no engine noise or exhaust noise is generated. Since all the driving | running | working area | regions drive | work with an electric motor, all the motor vehicles are very quiet motorized moving bodies. However, pedestrians, bicycle drivers, etc. that exist in the vicinity of such highly quiet electric vehicles, such as hybrid cars, electric cars, fuel cell cars, etc. that run with an electric motor that generates little noise and is quiet. Since the approach of the electric vehicle cannot be recognized by sound, it causes a contact accident between a highly quiet electric vehicle and a pedestrian or the like.

  For this reason, in order to solve the above-mentioned problem that quietness, which should be an advantage provided by hybrid vehicles, fuel cell vehicles, electric vehicles, etc., is sometimes harmful, a warning is provided at the driver's intention provided in conventional vehicles. Various systems for informing the presence of the own vehicle that operate independently of the driver's intention other than the horn that emits have been proposed.

  For example, in Patent Document 1, an alarm sound is generated when the vehicle starts to start, and the magnitude of the alarm sound is changed so as to increase for the first 5 seconds and then decrease. A small warning sound is continued until the vehicle speed exceeds 10 km / h. In this case, the loudness of the warning sound is gradually reduced with time, the sound pressure of the warning sound is changed alternately in magnitude, or the loudness of the warning sound is changed by changing the vehicle speed. Examples of alarm sounds include alarm sounds, melody sounds, sounds, and sounds composed of a plurality of frequencies.

  Moreover, in patent document 2, it has a frequency according to the rotational speed of a motor, has a frequency according to a vehicle speed detected by a pseudo sound signal having an amplitude according to an accelerator opening, and a vehicle speed sensor, and has an accelerator opening. A pseudo sound signal having an amplitude corresponding to the frequency is generated by a computer and output from a speaker via an amplifier. Whether to use a pseudo sound based on the motor speed or a pseudo sound based on the vehicle speed is selected by a switch. Further, it is described that a pseudo sound having a frequency based on the motor speed and a frequency based on the vehicle speed may be generated.

  Further, in Patent Document 3, in an alarm device that detects a person or other vehicle existing around the vehicle and notifies the vehicle driver of the presence, the alarm sound is modulated into a single frequency sound. It is disclosed that the sound has a fluctuating sound that gives the sound, and that the sound has a different fluctuation so that the driver can distinguish between the marker sound and the warning sound.

JP 2005-343360 A JP-A-7-32948 Japanese Patent Laying-Open No. 2009-42843 (paragraph numbers 0015 and 0016)

  These conventional alarm sound generators and pseudo sound generators have the following problems. Patent Document 1 proposes changing the overall size of an alarm sound, and as an alarm sound, an alarm sound, a melody sound, a voice, a sound composed of a plurality of frequencies, and the like. It seems that there is a sense of incongruity for pedestrians. Further, Patent Document 2 discloses that a pseudo sound having a frequency corresponding to the vehicle speed is generated, but only a sine wave example is shown as to what specific sound quality the sound is. It seems that pedestrians feel uncomfortable. Furthermore, the alarm device of Patent Document 3 is an alarm device for a driver, and there is only a disclosure of a sound that merely modulates a single frequency sound with respect to a fluctuating sound. It is thought that the sound is uncomfortable.

  The conventional alarm sound generators of electric vehicles such as conventional alarm sound generators and pseudo-sound generators are only considered to be sounds that are easily noticed by pedestrians, etc. That was hardly considered. The present invention was made in order to solve the above-described problems of the conventional electric mobile body alarm sound generation device, and it is easy for surrounding pedestrians and the like to easily notice the presence of the electric mobile object without a sense of incongruity. It is an object of the present invention to provide a notification sound generating device that generates sound.

  The notification sound control device used in the notification sound generator for an electric vehicle according to the present invention includes a basic sound source, a filter processing unit for extracting a signal in a part of a frequency band from a sound signal generated by the basic sound source, and the filter. A synthesis unit that synthesizes a fluctuation processing unit that performs fluctuation processing on a signal extracted by the processing unit, a signal in a frequency band of at least a main component of a sound signal generated by a basic sound source, and a signal that has been subjected to fluctuation processing by the fluctuation processing unit And a sound generator that emits sound by the signal synthesized by the synthesis unit.

  According to the present invention, since fluctuation processing is performed only on signals in a part of the frequency band among the sound signals generated by the basic sound source, surrounding pedestrians and the like can accept the notification sound without feeling uncomfortable. It is possible to provide a notification sound generating device that can easily recognize the presence of an electric mobile body without a sense of incongruity than only the basic sound source while maintaining the timbre of the basic sound source by the sound having fluctuations in the frequency band of the part.

It is a block diagram which shows schematic structure of the notification sound generator provided with the notification sound control apparatus of the electrically-driven moving body by Embodiment 1 of this invention. It is a conceptual diagram which shows the structure of the electrically-driven moving body provided with the notification sound generator by this invention. It is a diagram which shows an example of a process of the filter process part of the alerting | reporting sound control apparatus of the electrically driven moving body by Embodiment 1 of this invention. It is a diagram which shows another example of the process of the filter process part of the alerting | reporting sound control apparatus of the electrically-driven moving body by Embodiment 1 of this invention. It is a block diagram which shows an example of a structure of the fluctuation process part of the alerting | reporting sound control apparatus of the electrically-driven moving body by Embodiment 1 of this invention. FIG. 6 is a diagram showing an operation according to the configuration of the fluctuation processing unit of FIG. 5. It is a block diagram which shows another example of a structure of the fluctuation process part of the alerting | reporting sound control apparatus of the electrically-driven moving body by Embodiment 1 of this invention. It is a diagram which shows the operation | movement by the structure of the fluctuation process part of FIG. It is a block diagram which shows another example of a structure of the fluctuation | variation process part of the notification sound control apparatus of the electrically-driven moving body by Embodiment 1 of this invention. It is a block diagram which shows another example of a structure of the fluctuation | variation process part of the notification sound control apparatus of the electrically-driven moving body by Embodiment 1 of this invention. It is a block diagram which shows schematic structure of the notification sound generator provided with the notification sound control apparatus of the electrically-driven moving body by Embodiment 2 of this invention. It is a block diagram which shows schematic structure of the notification sound generator provided with the notification sound control apparatus of the electrically-driven moving body by Embodiment 3 of this invention. It is a block diagram which shows schematic structure of the alerting | reporting sound control apparatus of the electrically-driven moving body by Embodiment 4 of this invention. It is a diagram which shows the characteristic of the filter process part of the alerting | reporting sound control apparatus of the electrically-driven moving body by Embodiment 4 of this invention. It is a block diagram which shows schematic structure of the notification sound generator provided with the notification sound control apparatus of the electrically-driven moving body by Embodiment 5 of this invention. It is a block diagram which shows schematic structure of the notification sound generator provided with the notification sound control apparatus of the electrically-driven moving body by Embodiment 6 of this invention. It is a diagram which shows an example of the process of the filter process part of the alerting | reporting sound control apparatus of the electrically driven moving body by Embodiment 6 of this invention.

Embodiment 1 FIG.
FIG. 1 is a block diagram of a schematic configuration of a notification sound generating apparatus provided with a notification sound control apparatus according to Embodiment 1 of the present invention, and FIG. 1 is a conceptual diagram of a configuration of an electric vehicle including the notification sound generating apparatus of the present invention. It is shown in 2. As shown in FIG. 2, in an electric vehicle 1 that electrically generates part or all of a driving force by an electric motor or the like, such as an electric vehicle or a hybrid vehicle, the presence of the electric vehicle 1 is indicated to surrounding pedestrians or the like. What is provided for the recognition is the notification sound generator 2. The notification sound generating device 2 includes a notification sound control device 3 that controls the notification sound to be generated and a sounding body 4 for radiating the notification sound. The sounding body 4 is, for example, a speaker, but may be anything other than a so-called speaker as long as it can convert an electrical signal into sound.

  The configuration of the notification sound control device 3 of the notification sound generation device 2 according to Embodiment 1 of the present invention will be described with reference to FIG. First, the basic sound source 5 generates a sound signal that is a source of the notification sound. The signal of the basic sound source 5 is, for example, a signal that simulates the engine sound of a conventional automobile, or a signal obtained by processing the sound generated by the electric mobile body 1 by using a microphone or the like. Any signal may be used as long as the signal is recognized by a person. A part of the frequency band of the sound signal generated by the basic sound source 5 is extracted by the filter processing unit 6, and the extracted signal is subjected to fluctuation processing by the fluctuation processing unit 7. The amplitude of the signal subjected to the fluctuation processing in the fluctuation processing unit 7 is adjusted in the amplitude adjusting unit 8 and synthesized with the signal from the original basic sound source 5 in the synthesizing unit 9. The synthesized signal is amplified by the amplifier 10 so as to be an appropriate signal for driving the sounding body 4, the sounding body 4 is driven by the amplified signal, and the notification sound is emitted from the sounding body 4.

  The processing in the filter processing unit 6 will be described with reference to FIG. In FIG. 3A, an example of a sound signal generated by the basic sound source 5 is shown by a solid line. Further, the characteristics of the filter of the filter processing unit 6 are indicated by broken lines. In FIG. 3A, the horizontal axis represents frequency, and the vertical axis represents sound pressure and filter attenuation. The attenuation amount of the filter shows that the attenuation amount is large as it goes down. The sound generated by the basic sound source 5 usually has a frequency component with a high sound pressure level as a main component. In FIG. 3A, the frequency band that is the main component is indicated by a. A normal sound has a component of a certain sound pressure level in a frequency band that is a harmonic relative to the frequency band of the main component. For example, a band that is twice (second order) higher harmonics than the band a is indicated by b in FIG.

  As in the filter characteristic indicated by the broken line in FIG. 3, the filter processing unit 6 extracts a signal having a frequency component higher than the second harmonic by a high-pass filter having a cutoff frequency between the band a and the band b. FIG. 3B shows an example of the signal F extracted by filtering using the filter characteristic indicated by the broken line in FIG. However, the band extracted by the filter processing is not limited to the band higher than the second harmonic of the main component. For example, as shown in FIG. 4, the cut-off frequency is within the frequency band of the main component of the sound signal generated by the basic sound source 5, and the frequency band extracted by the filter processing is the sound signal generated by the basic sound source 5. A part of the frequency band may be included. FIG. 4B shows an example of the signal F extracted by filtering using the filter characteristic indicated by the broken line in FIG. As described above, the frequency band of the signal extracted by the filter processing unit 6 may be a partial frequency band of the sound signal generated by the basic sound source 5, but preferably has a band that does not include all the main components. More preferably, the band of the main component harmonic or the band of the subharmonic is good without including the band of the main component.

  Here, the main component frequency band is a band component having a relatively high amplitude level in the frequency band of the basic sound source 5, that is, when the sound generated by the basic sound source 5 is listened to. The band component that can be heard.

  The fluctuation processing unit 7 performs fluctuation processing on the signal extracted by the filter processing by the filter processing unit 6. The processing in the fluctuation processing unit 7 will be described with reference to FIGS. FIG. 5 is a block diagram illustrating an example of the configuration of the fluctuation processing unit 7. In FIG. 5, as fluctuation processing, a filter processing unit 6 performs filtering to extract a signal in a predetermined frequency band, and the amplitude modulation unit 71 performs amplitude modulation on the extracted signal. The amplitude modulation process is performed based on the amplitude modulation coefficient generated by the amplitude modulation coefficient generation unit 72. As parameters of the amplitude modulation coefficient, for example, there are a modulation frequency which is a modulation period, and an amplitude variation range which is varied by the modulation. An image of a signal modulated by the amplitude modulation unit 71 based on the modulation coefficient generated by the amplitude modulation coefficient generation unit 72 is shown in FIG. As shown in FIG. 6, the sound pressure level of the signal extracted by filtering by the filter processing unit 6 fluctuates by a fluctuation width Δm in a certain cycle, that is, the amplitude fluctuates. The modulation frequency, which is a modulation parameter, and the amplitude fluctuation range to be varied by the modulation may further change with time. Further, the amplitude may be changed at random.

  FIG. 7 is a block diagram illustrating another example of the configuration of the fluctuation processing unit 7. In FIG. 7, as fluctuation processing, the frequency modulation unit 73 performs frequency modulation on the signal extracted by filtering processing by the filter processing unit 6. The frequency modulation process is performed based on the modulation coefficient generated by the frequency modulation coefficient generation unit 74. As a parameter of the frequency modulation coefficient, there are, for example, a modulation frequency and a fluctuation range of a frequency that is changed by the modulation. An image of a signal modulated by the frequency modulation unit 73 based on the modulation coefficient generated by the frequency modulation coefficient generation unit 74 is shown in FIG. As shown in FIG. 8, the frequency of the signal extracted by filtering by the filter processing unit 6 fluctuates by, for example, a fluctuation width Δf in a certain period, that is, the frequency fluctuates. The modulation frequency, which is a modulation parameter, and the fluctuation range of the frequency fluctuated by the modulation may further change with time. Further, the frequency may be changed at random.

  FIG. 9 and FIG. 10 are block diagrams showing still another example of the configuration of the fluctuation processing unit 7. 9 and 10, the same reference numerals as those in FIG. 5 or 7 indicate the same or corresponding parts. In the configuration shown in FIG. 9, the amplitude modulation unit 71 first amplitude-modulates the signal that has been filtered out by the filter processing unit 6. The frequency modulation unit 73 further frequency-modulates the signal that has been subjected to amplitude modulation to generate fluctuations in amplitude. With this configuration, processing that fluctuates both the amplitude and frequency can be performed. Further, in the configuration shown in FIG. 10, the frequency modulation unit 73 first frequency-modulates the signal extracted by filtering processing by the filter processing unit 6. The amplitude modulation unit 71 further modulates the amplitude of the signal that has been subjected to frequency modulation to generate fluctuations in the frequency. With this configuration, it is possible to perform processing in which both the amplitude and the frequency fluctuate in the same manner as the fluctuation processing unit 7 having the configuration shown in FIG.

  The signal processed by the fluctuation processing unit 7 is combined with the signal from the original basic sound source 5 by the combining unit 9. At this time, in order to make the amplitude ratio between the signal of the basic sound source 5 and the signal processed by the fluctuation processing unit 7 appropriate, after the amplitude of the signal processed by the fluctuation processing unit 7 is adjusted by the amplitude adjustment unit 8, The synthesizer 9 synthesizes the signal from the basic sound source 5. As a result of the synthesis, the synthesized signal has no fluctuation in the main component band of the sound signal generated by the basic sound source 8, and the frequency band processed and extracted by the filter processing unit 6 becomes a fluctuation signal. A sound corresponding to this signal is emitted from the body 4 as a notification sound.

  In the case of a basic sound source having a band as shown in FIG. 3A, a person mainly hears a sound in a band a which is a main component, that is, a sound in a band having a high sound pressure level in the basic sound source. Therefore, if the entire band or the band indicated by “a” fluctuates, the band that can be heard mainly fluctuates, so that the image of the basic sound source is destroyed, which also gives the listener a sense of incongruity. However, if only the band b in FIG. 3A, that is, the band having a relatively low sound pressure level as compared with the band a, which is the main component, fluctuates, the band that can be heard mainly does not fluctuate and only the low volume band. Because it fluctuates, the listener can feel the fluctuation without feeling uncomfortable without destroying the image of the basic sound source.

  The notification sound generator according to the first embodiment radiates such a sound as a notification sound of the electric vehicle, in which only the low sound volume band fluctuates without changing the main audible band. Thus, it is possible to generate a notification sound that makes it easier to notice the presence of the electric vehicle compared to the basic sound source without destroying the image of the basic sound source. That is, it is possible to obtain a notification sound generating device that can more easily recognize the presence of the electric vehicle than the basic sound source while maintaining the timbre of the basic sound source.

Embodiment 2. FIG.
FIG. 11 shows a block diagram of a schematic configuration of a notification sound generating apparatus including the notification sound control apparatus according to the second embodiment of the present invention. 11, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. In the second embodiment, the fluctuation process is changed according to the vehicle speed. For this reason, for example, a vehicle speed signal provided in the electric vehicle 1 is input to the vehicle speed detection unit 12, and vehicle speed information is sent to the filter processing unit 6, the fluctuation processing unit 7, and the amplitude adjustment unit 8. Examples of vehicle speed information output by the vehicle speed detection unit 12 include (x), (y), (x) 0, (y) 0 to less than 20 km / hr, (z) 20 km / hr or more. (Z) Information indicating which of the three areas is used.

  The filter processing unit 6 receives this vehicle speed information and changes the filter characteristics in accordance with the vehicle speed region. That is, the frequency band extracted by the filter processing unit 6 is changed for each of the three vehicle speed regions. For example, whenever the frequency changes (x), (y), and (z), the frequency band extracted by the filter processing unit 6 is changed to the high tone side or to the low tone side.

  The fluctuation processing unit 7 receives the information on the vehicle speed, and changes the way of processing the fluctuation according to the area of the vehicle speed. For example, when the configuration of the fluctuation processing unit 7 is the configuration of FIG. 5, for example, the modulation coefficient generated by the amplitude modulation coefficient generation unit 72 is changed for each of the three vehicle speed regions. For example, every time it changes to (x), (y), (z), the amplitude fluctuation range of the amplitude modulation is increased or decreased. Further, the modulation frequency of the amplitude modulation is increased, that is, the change of the amplitude is increased every time the vehicle speed region changes ((x), (y), (z), or the modulation frequency of the amplitude modulation is decreased. That is, every time the vehicle speed region changes to (x), (y), (z), the change in amplitude is delayed.

  The amplitude adjustment processing unit 8 receives vehicle speed information and changes the amplitude according to the vehicle speed region. For example, every time it changes to (x), (y), (z), the amplitude of the signal subjected to the fluctuation processing by the fluctuation processing unit in the amplitude adjusting unit 8 is increased or decreased.

  It is also conceivable that the fluctuation process is not performed in a certain vehicle speed region. For example, when the vehicle speed is high, for example, 50 km / h or more, the fluctuation processing is not performed. For example, when the vehicle speed is 50 km / h or higher, the amplitude adjusting unit 8 performs a process of setting the output to zero.

  As described above, the processes of the filter processing unit 6, the fluctuation processing unit 7, and the amplitude adjustment unit 8 are changed according to the vehicle speed region. However, it is not necessary to change all the processes of the filter processing unit 6, the fluctuation processing unit 7, and the amplitude adjustment unit 8, and it is sufficient to change at least one process. Further, although the vehicle speed detection unit 12 divides the vehicle speed region into three, it may be divided into two, or four or more, instead of the three regions. Further, at least one of the filter processing unit 6, the fluctuation processing unit 7, and the amplitude adjustment unit 8 may be changed continuously corresponding to the vehicle speed without dividing the vehicle speed into regions. In this case, the vehicle speed detection unit 12 may not be provided, and the filter processing unit 6, the fluctuation processing unit 7, and the amplitude adjustment unit 8 may input the vehicle speed signal itself.

  As described above, when the process is changed according to the vehicle speed, it is possible to generate a notification sound capable of recognizing the vehicle speed feeling of the electric vehicle. That is, when the listener can recognize the vehicle speed from the timbre, it becomes easy for the listener to understand whether the electric vehicle is approaching slowly or quickly.

Embodiment 3 FIG.
FIG. 12 shows a block diagram of a schematic configuration of a notification sound generating apparatus including the notification sound control apparatus according to Embodiment 3 of the present invention. 12, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. The third embodiment is an embodiment where the frequency distribution of the sound signal generated by the basic sound source 5 changes. For example, the vehicle speed detection unit 120 receives the vehicle speed signal, detects the vehicle speed, sends the vehicle speed detection signal to the basic sound source 5, and the basic sound source 5 changes the frequency distribution of the sound signal generated according to the vehicle speed. The sound quality changes according to the vehicle speed. For example, the sound generated by the basic sound source 5 is controlled so that the frequency of the main component of the sound increases as the vehicle speed increases. The frequency analysis unit 13 analyzes the frequency distribution of the sound signal of the basic sound source 5 in which the frequency distribution changes.

  For example, the frequency analysis unit 13 analyzes the frequency band of the main component of the sound generated by the basic sound source 5. When the frequency distribution of the sound signal generated by the basic sound source 5 is such a signal as shown in FIG. 3, it is analyzed that the band indicated by a is the main frequency band. Then, the band indicated by b which is the second harmonic band is analyzed as a frequency band to be processed by the filter processing unit 6, and the analysis result is sent to the filter processing unit 6. Here, since the sound signal generated by the basic sound source 5 varies depending on the vehicle speed, the band indicated by b varies depending on the vehicle speed. The filter processing unit 6 extracts a signal in the band indicated by b from the sound signal generated by the basic sound source 5, performs fluctuation processing on this signal by the fluctuation processing unit 7, adjusts the amplitude by the amplitude adjustment unit 8, and then combines it by the synthesis unit 9. It is synthesized with the sound signal generated by the original basic sound source 5.

  As described above, in the third embodiment, when the sound quality of the sound signal generated by the basic sound source 5 changes, the frequency analysis unit 13 analyzes the change in the sound quality, and the frequency band taken out by the filter processing unit 6. That is, the frequency band of the signal subjected to the fluctuation processing by the fluctuation processing unit 6 is changed according to the sound quality of the sound signal generated by the basic sound source 5. Even if the sound quality of the sound generated by the basic sound source 5 changes, the signal in the frequency band corresponding to the sound quality is processed to fluctuate, so that it is close to the natural sound image of the basic sound source and pedestrians around the electric vehicle Sound that is easy to recognize.

Embodiment 4 FIG.
FIG. 13 shows a block diagram of a schematic configuration of the notification sound control apparatus according to the fourth embodiment of the present invention. 13, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. In the third embodiment, a plurality of fluctuation components can be added. As shown in FIG. 13, a plurality of sets of filter processing units, fluctuation processing units, and amplitude adjustment units are provided. The filter processing unit 61, the filter processing unit 62, and the filter processing unit 63 have different filter characteristics, and the frequency bands of signals sent to the fluctuation processing unit 701, the fluctuation processing unit 702, and the fluctuation processing unit 703 are different.

  The frequency bands of the signals extracted by the filter processing unit 61, the filter processing unit 62, and the filter processing unit 63 are different from the frequency band of the main component of the sound generated by the basic sound source 5, and each is a different frequency band. is there. FIG. 14 shows an example of the filter characteristics of each filter processing unit. As shown in FIG. 14, for example, the filter processing unit 61 performs a filtering process to extract the second-order harmonic band b of the main component frequency band, and the filter processing unit 62 performs the third-order harmonic of the main component frequency band. A filter process for extracting the wave band c is performed, and a filter process for extracting the band d of the fourth harmonic of the main frequency band is performed. Here, the frequency bands of the second harmonic, the third harmonic, and the fourth harmonic are taken out. However, the frequency band is not limited to this, and the processing in each filter processing unit is different from the frequency band of the main component. This is a filter process for extracting the band, and it is sufficient that the characteristics of each filter are different.

  The fluctuation processing in the fluctuation processing unit 701, the fluctuation processing unit 702, and the fluctuation processing unit 703 are preferably different processes, but may be the same. For example, when each fluctuation processing unit is configured as shown in FIG. 5, it is desirable that the amplitude modulation coefficients generated by the respective amplitude modulation coefficient generation units are different. That is, it is desirable that the modulation period and the amplitude fluctuation range differ between the fluctuation processing unit 701, the fluctuation processing unit 702, and the fluctuation processing unit 703. However, each fluctuation processing unit may perform amplitude modulation based on the modulation coefficient generated by the same modulation coefficient generation unit.

  The signals subjected to the fluctuation processing by the fluctuation processing unit 701, the fluctuation processing unit 702, and the fluctuation processing unit 703 are amplitude-adjusted by the amplitude adjustment unit 81, the amplitude adjustment unit 82, and the amplitude adjustment unit 83, respectively, and then are combined. Then, the sound is synthesized by the synthesizing unit 93 and further synthesized by the synthesizing unit 9 with the sound signal generated by the five basic sound sources. The sound signal synthesized by the synthesizer 9 is amplified to a signal for driving the sounding body 4 by the amplifier 10 as in the configuration shown in FIG.

  As described above, in the fourth embodiment, filters having different characteristics are configured, fluctuation processing is performed on extracted sound sources having different frequencies and bands, and after adjusting each level ratio, addition processing is performed. A sound source was generated. For this reason, fluctuation sound sources with different levels can be generated for a specific band, so that the sound is more natural, close to the sound image of the basic sound source, and easily recognized by pedestrians around the electric vehicle. .

Embodiment 5 FIG.
FIG. 15 shows a block diagram of a main part of a notification sound generating device including the notification sound control device according to the fifth embodiment of the present invention. 15, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. In the fifth embodiment, as shown in FIG. 15, after the signal from the additional sound source 14 is synthesized by the additional sound source synthesizing unit 90 with the signal subjected to the fluctuation processing by the fluctuation processing unit 7, the amplitude is adjusted by the amplitude adjusting unit 8. The synthesis unit 9 synthesizes the sound signal generated by the basic sound source 5.

  The sound generated by the additional sound source 14 is, for example, a sound source that does not need to be subjected to fluctuation processing or a sound source having a white noise component. As described above, in the fifth embodiment, since the signal of the additional sound source is synthesized with the signal subjected to the fluctuation processing, the sound source that is not desired to be subjected to the fluctuation processing different from the basic sound source 5 is synthesized in the band to be subjected to the fluctuation processing. It becomes a sound that can be easily recognized by pedestrians and the like around a more natural electric vehicle.

Embodiment 6 FIG.
FIG. 16 shows a block diagram of a main part of a notification sound generating apparatus including the notification sound control apparatus according to the sixth embodiment of the present invention. 16, the same reference numerals as those in FIG. 1 denote the same or corresponding parts. The filter processing unit 64 according to the sixth embodiment separates the sound signal generated by the basic sound source 5 into a frequency band signal M including the main component and a frequency band signal F not including the main component. In the fluctuation processing unit 7, fluctuation processing is performed on the signal F in the frequency band not including the main component, the amplitude of the fluctuation processed signal is adjusted by the amplitude adjustment unit 8, and the main signal separated by the filter processing unit 64 is obtained. The signal is synthesized by the synthesis unit 9 with the signal M in the frequency band including the components.

  An example of the signal filtered by the filter processing unit 64 is shown in FIG. FIG. 17 shows an example in which the sound signal generated by the basic sound source 5 is a signal as indicated by a solid line in FIG. FIG. 17A shows a frequency band signal M including the main component, and FIG. 17B shows a frequency band signal F not including the main component. The signal F is subjected to fluctuation processing and then combined with the signal M.

  As the configuration of the filter processing unit 64, for example, the signal M is extracted by a low-pass filter having the characteristics indicated by the broken line in FIG. 17A, and the signal F is extracted by the high-pass filter having the characteristics indicated by the broken line in FIG. Further, the signal F is not limited to the signal extracted by the high-pass filter, and a signal in a predetermined frequency band may be extracted by a band-pass filter, for example. In this case, the signal M may be created by subtracting the signal F from the sound signal generated by the original basic sound source 5. In this way, the signal M may be a signal that does not include the band of the signal F, the signal F may be subjected to fluctuation processing, and synthesized with the signal M.

  As described above, in the sixth embodiment, the signal subjected to the fluctuation processing is synthesized with the sound signal in the frequency band not including the frequency band of the signal subjected to the fluctuation processing. Thus, the effect of the fluctuation processing is transmitted more remarkably, and pedestrians can feel the fluctuation more comfortably.

1: Electric moving body 2: Notification sound generating device 3: Notification sound control device 4: Sound generator 5: Basic sound source 6, 61, 62, 63, 64: Filter processing unit 7, 701, 702, 703: Fluctuation processing unit 9 : Synthesizer 12, 120: Vehicle speed detector 13: Frequency analyzer 14: Additional sound source

Claims (11)

  A notification sound control device for controlling a notification sound radiated to the outside from an electric mobile body that generates at least a part of driving force by an electric motor, comprising a basic sound source and a sound signal generated by the basic sound source A filter processing unit that extracts a signal in a frequency band, a fluctuation processing unit that performs a fluctuation process on the signal extracted by the filter processing unit, a signal in a frequency band of at least a main component of a sound signal generated by the basic sound source, A notification sound control device for an electric vehicle, comprising: a combining unit that combines the signal subjected to the fluctuation processing by the fluctuation processing unit.   The notification sound of the electric mobile body according to claim 1, wherein the filter processing unit extracts a signal in a frequency band not including all frequency bands of a main component of a sound signal generated by the basic sound source. Control device.   The notification sound control of the electric mobile body according to claim 2, wherein the filter processing unit extracts a signal in a frequency band of a higher harmonic of a frequency band of a main component of a sound signal generated by the basic sound source. apparatus.   The apparatus according to claim 1, wherein the fluctuation processing unit performs a process of modulating the amplitude of a signal.   The apparatus according to claim 1, wherein the fluctuation processing unit performs processing for frequency-modulating a signal.   The notification sound control device for an electric vehicle according to claim 1, wherein the filter processing unit changes a frequency band to be extracted according to a vehicle speed of the electric vehicle.   The apparatus according to claim 1, wherein the fluctuation processing unit changes a parameter of fluctuation processing according to a vehicle speed of the electric moving body.   The basic sound source is a sound source in which the sound quality of the generated sound changes, and includes a frequency component analysis unit that analyzes a frequency distribution of a sound signal generated by the basic sound source, and the filter processing unit includes the frequency component analysis The notification sound control device for an electric vehicle according to claim 1, wherein the frequency band to be extracted is changed in accordance with the frequency distribution analyzed by the unit.   Equipped with a plurality of filter processing units with different frequency bands of the signals to be extracted, and a plurality of fluctuation processing units for processing the fluctuations of the signals extracted by the respective filter processing units, and the signals processed by the plurality of fluctuation processing units The notification sound control device for an electric vehicle according to claim 1, further comprising a synthesizing unit.   The notification sound control device for an electric vehicle according to claim 1, further comprising an additional sound source, wherein the signal subjected to the fluctuation processing by the fluctuation processing unit and the signal of the sound generated by the additional sound source are synthesized.   11. A notification sound for an electric mobile body comprising a sounding body that emits sound based on a signal obtained from the notification sound control device for an electric mobile body according to any one of claims 1 to 10. Generator.

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