Active effective sound generator and control method of active effective sound generator

Abstract

To provide an active effective sound generator which can reduce a size of sound source data of pseudo sound corresponding to a magnitude of vehicle acceleration stored in a storage part, and to provide a control method of the generator.SOLUTION: An active effective sound generator 10 for generating effective sound Sc from a speaker 12 provided in a vehicle driven by an electric motor includes: a storage part 16 for storing information of sound consisting of a plurality of frequency components in a first frequency band as sound source data; a linked sound generation part 18 for generating sound consisting of a plurality of frequency components in a second frequency band corresponding to rotational speed of the electric motor, as linked sound, from the sound source data; and an effective sound generation part 30 for generating effective sound generated from the speaker by using the linked sound.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an active sound effect generating device and a control method for an active sound effect generating device. [Background technology]

[0002] The following Patent Document 1 discloses an artificial sound generating device. In this artificial sound generating device, an artificial sound corresponding to the magnitude of the acceleration of the vehicle is stored in a storage unit. Sound information generated using the artificial sound stored in the storage unit is output to an audio device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-105923 A Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in the above-mentioned Patent Document 1 requires artificial sounds that correspond to the acceleration and the like of the vehicle, and therefore has a problem in that the amount of artificial sound data stored in the storage unit becomes enormous.

[0005] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0006] A first aspect of the present invention is an active sound effect generating device that generates sound effects from a speaker provided in a vehicle driven by an electric motor, the active sound effect generating device having a memory unit that stores sound information consisting of a plurality of frequency components in a first frequency band as sound source data, a linked sound generation unit that generates, from the sound source data, a sound consisting of a plurality of frequency components in a second frequency band corresponding to the rotation speed of the electric motor as a linked sound, and a sound effect generation unit that uses the linked sound to generate the sound effect to be generated from the speaker.

[0007] A second aspect of the present invention is a control method for an active sound effect generating device that generates sound effects from a speaker provided in a vehicle driven by an electric motor, the control method comprising a linked sound generation step of generating, as a linked sound, a sound consisting of a plurality of frequency components in a second frequency band corresponding to the rotation speed of the electric motor from sound source data, which is information on sound consisting of a plurality of frequency components in a first frequency band, and a sound effect generation step of generating the sound effect using the linked sound. Effect of the Invention

[0008] According to the present invention, the size of the sound source data can be reduced. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing the configuration of an active sound effect generating device. [Diagram 2] FIG. 2 is an image diagram showing the frequency band of the linked sound and the frequency band of the background sound. [Diagram 3] FIG. 3 is a graph showing frequency components of the electric motor sound and frequency components of a composite sound of the electric motor sound and a sound effect generated from a speaker. [Figure 4] FIG. 4 is a block diagram showing the configuration of the first linked sound generating unit. [Diagram 5] FIG. 5 is a map of the gain. [Figure 6] FIG. 6 is a map of the gain. [Figure 7] FIG. 7 is a map of the gain. [Figure 8] FIG. 8 is a map of the gain. [Figure 9] FIG. 9 is a map of the gain. [Figure 10] FIG. 10 is a block diagram showing the configuration of the first background sound generation unit. [Figure 11] FIG. 11 is a flowchart of the sound effect generation process executed in the active sound effect generation device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Configuration of active sound effect generator] 1 is a block diagram showing the configuration of an active sound effect generating device 10. The active sound effect generating device 10 is mounted on a vehicle driven by an electric motor. Vehicles driven by an electric motor include a BEV (Battery Electric Vehicle), a HEV (Hybrid Electric Vehicle), a PHEV (plug-in Hybrid Electric Vehicle), a FCEV (Fuel Cell Electric Vehicle), etc.

[0011] The active sound effect generating device 10 is a device that outputs sound effects that change according to the rotation speed of an electric motor from a speaker 12 provided in the passenger compartment of an electric vehicle. The sound effects increase the attractiveness of the electric vehicle to passengers.

[0012] The active sound effect generating device 10 includes a calculation unit 14 and a storage unit 16. The calculation unit 14 is, for example, a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit).

[0013] The calculation unit 14 has a first linked sound generation unit 18, a second linked sound generation unit 20, a first background sound generation unit 22, a second background sound generation unit 24, a third background sound generation unit 26, a fourth background sound generation unit 28, and a sound effect generation unit 30. The first linked sound generation unit 18, the second linked sound generation unit 20, the first background sound generation unit 22, the second background sound generation unit 24, the third background sound generation unit 26, the fourth background sound generation unit 28, and the sound effect generation unit 30 are realized by the calculation unit 14 executing a program stored in the storage unit 16.

[0014] At least a part of the first linked sound generation unit 18, the second linked sound generation unit 20, the first background sound generation unit 22, the second background sound generation unit 24, the third background sound generation unit 26, the fourth background sound generation unit 28, and the sound effect generation unit 30 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). At least a part of the first linked sound generation unit 18, the second linked sound generation unit 20, the first background sound generation unit 22, the second background sound generation unit 24, the third background sound generation unit 26, the fourth background sound generation unit 28, and the sound effect generation unit 30 may be realized by an electronic circuit including a discrete device.

[0015] The storage unit 16 is configured by a volatile memory (not shown) and a non-volatile memory (not shown) which are computer-readable storage media. The volatile memory is, for example, a random access memory (RAM). The non-volatile memory is, for example, a read only memory (ROM) or a flash memory. Data and the like are stored, for example, in the volatile memory. Programs, tables, maps, and the like are stored, for example, in the non-volatile memory.

[0016] At least a part of the storage unit 16 may be provided in the above-mentioned processor, integrated circuit, etc. At least a part of the storage unit 16 may be mounted on a device connected to the active sound effect generation device 10 via a network.

[0017] The storage unit 16 stores sound source data. The sound source data is information on a sound (hereinafter, sometimes referred to as a sound source) consisting of a plurality of frequency components in a first frequency band. The sound source data is digital data sampled at a predetermined sampling period. The sound source data has data that corresponds to a predetermined playback time when the sound source is played back at a playback speed of 1x. The first frequency band is, for example, 650 Hz to 950 Hz, and has a center frequency of 800 Hz. The first frequency band is not limited to 650 Hz to 950 Hz, and may be another frequency band. The sound source may include frequency components evenly across the entire range of the first frequency band. The sound pressures (amplitudes) of the frequency components included in the sound source may be equal to each other.

[0018] The active sound effect generating device 10 generates an interlocking sound that changes in conjunction with the fluctuation of the rotation speed of the electric motor, and a background sound that does not change in conjunction with the fluctuation of the rotation speed of the electric motor. Figure 2 is an image diagram showing the frequency band of the interlocking sound and the frequency band of the background sound.

[0019] The first interlocking sound generating unit 18 generates the first interlocking sound Sa1. The first interlocking sound Sa1 is a sound made up of a plurality of frequency components in a predetermined frequency band (the frequency band in the range indicated by A in FIG. 2) centered on the 24th frequency of the rotation speed of the electric motor.

[0020] The second interlocking sound generating unit 20 generates the second interlocking sound Sa2. The second interlocking sound Sa2 is a sound composed of a plurality of frequency components in a predetermined frequency band (the frequency band in the range indicated by B in FIG. 2) centered on the 48th frequency of the rotation speed of the electric motor.

[0021] The first background sound generation unit 22 generates the first background sound Sb1. The first background sound Sb1 is a sound composed of a plurality of frequency components in a predetermined frequency band (the frequency band indicated by C in FIG. 2) centered on a frequency f1. The first selection switch 32 switches between a state in which the first background sound Sb1 is output to the sound effect generation unit 30 and a state in which the first background sound Sb1 is not output to the sound effect generation unit 30. In this embodiment, the first selection switch 32 selects the state in which the first background sound Sb1 is output to the sound effect generation unit 30.

[0022] The second background sound generation unit 24 generates the second background sound Sb2. The second background sound Sb2 is a sound consisting of a plurality of frequency components in a predetermined frequency band (the frequency band in the range indicated by D in FIG. 2) centered on the frequency f2. The second selection switch 34 switches between a state in which the second background sound Sb2 is output to the sound effect generation unit 30 and a state in which the second background sound Sb2 is not output to the sound effect generation unit 30. In this embodiment, the second selection switch 34 selects the state in which the second background sound Sb2 is output to the sound effect generation unit 30.

[0023] The third background sound generation unit 26 generates the third background sound Sb3. The third background sound Sb3 is a sound composed of a plurality of frequency components in a predetermined frequency band (the frequency band indicated by E in FIG. 2) centered on a frequency f3. The third selection switch 36 switches between a state in which the third background sound Sb3 is output to the sound effect generation unit 30 and a state in which the third background sound Sb3 is not output to the sound effect generation unit 30. In this embodiment, the third selection switch 36 selects the state in which the third background sound Sb3 is output to the sound effect generation unit 30.

[0024] The fourth background sound generation unit 28 generates the fourth background sound Sb4. The fourth background sound Sb4 is a sound composed of a plurality of frequency components in a predetermined frequency band centered on a frequency f4. The fourth selection switch 38 switches between a state in which the fourth background sound Sb4 is output to the sound effect generation unit 30 and a state in which the fourth background sound Sb4 is not output to the sound effect generation unit 30. In this embodiment, the fourth selection switch 38 selects the state in which the fourth background sound Sb4 is not output to the sound effect generation unit 30.

[0025] The sound effect generation unit 30 generates the sound effect Sc by synthesizing the first linked sound Sa1, the second linked sound Sa2, the first background sound Sb1, the second background sound Sb2, the third background sound Sb3, and the fourth background sound Sb4. In this embodiment, since the fourth background sound Sb4 is not output to the sound effect generation unit 30, the sound effect generation unit 30 actually synthesizes the first linked sound Sa1, the second linked sound Sa2, the first background sound Sb1, the second background sound Sb2, and the third background sound Sb3 to generate the sound effect Sc.

[0026] Fig. 3 is a graph showing the frequency components of the electric motor sound and the frequency components of a composite sound of the electric motor sound and the sound effect Sc generated from the speaker 12. The graph shown by the thin line in Fig. 3 shows the frequency components of the electric motor sound, and the graph shown by the thick line shows the frequency components of the composite sound. Fig. 3 shows the frequency components when the electric motor is at rotation speed N1 (see Fig. 2). Note that the electric motor sound is not limited to the sound generated by the electric motor itself. The electric motor sound may also include the sound generated by a gear that rotates in synchronization with the electric motor.

[0027] As shown in FIG. 3, the sound pressure level of the 24th frequency component and the sound pressure level of the 48th frequency component stand out more than the sound pressure levels of the other frequency components. Therefore, the occupants of the vehicle hear the sound of the 24th frequency component and the sound of the 48th frequency component prominently, which gives the occupants a sense of discomfort. Therefore, by generating the first linked sound Sa1 and the second linked sound Sa2 from the speaker 12, the sound pressure level of the component of a predetermined frequency band centered on the 24th frequency and the sound pressure level of the component of a predetermined frequency band centered on the 48th frequency are increased (see the points indicated by A and B in FIG. 3). As a result, a synthetic sound that is linked to the fluctuation in the rotation speed of the electric motor and has a less prominent feeling of the sound of the 24th frequency component and the sound of the 48th frequency component can be obtained.

[0028] The order of the frequency component at which the sound pressure level is prominent varies depending on the specifications of the electric motor, the transmission, the powertrain, etc. Therefore, the order of the frequency component at which the sound pressure level is prominent is not limited to the 24th order or the 48th order. In addition, the number of locations at which the sound pressure level is prominent varies depending on the specifications of the electric motor, the transmission, the powertrain, etc. Therefore, the number of locations at which the sound pressure level is prominent is not limited to two (the 24th order and the 48th order). For example, when the sound pressure level is prominent in three locations, a third linked sound generation unit (not shown) may be provided in the active sound effect generation device 10 in addition to the first linked sound generation unit 18 and the second linked sound generation unit 20 shown in FIG. 1.

[0029] In addition, the vehicle body may resonate with the electric motor sound, and the sound pressure level of the vehicle body's resonant frequency component may stand out compared to the sound pressure levels of other frequency components. Therefore, the first background sound Sb1, the second background sound Sb2, and the third background sound Sb3 are generated from the speaker 12 to increase the sound pressure level of the components in a predetermined frequency band centered on the vehicle body's resonant frequency (see the points indicated by C, D, and E in FIG. 2). This makes it possible to produce a synthesized sound in which the prominence of the resonant sound is softened.

[0030] Since the resonance frequency differs depending on the vehicle body, the center frequencies of the first background sound Sb1, the second background sound Sb2, and the third background sound Sb3 are adjusted and determined for each vehicle body. In addition, since the number of resonance frequencies also differs depending on the vehicle body, the background sound is not limited to three types of the first background sound Sb1, the second background sound Sb2, and the third background sound Sb3, but may be two or less types of background sounds, or four or more types of background sounds. For example, when there are two types of background sounds, the third selection switch 36 shown in FIG. 1 may be set to select a state in which the third background sound Sb3 is not output to the sound effect generation unit 30. For example, when there are four types of background sounds, the fourth selection switch 38 shown in FIG. 1 may be set to select a state in which the fourth background sound Sb4 is output to the sound effect generation unit 30. For example, when there are five types of background sounds, in addition to the first background sound generation unit 22, the second background sound generation unit 24, the third background sound generation unit 26, and the fourth background sound generation unit 28 shown in FIG. 1, a fifth background sound generation unit (not shown) may be provided in the active sound effect generation device 10.

[0031] [Configuration of the linked sound generation unit] 4 is a block diagram showing the configuration of the first linked sound generating unit 18. The first linked sound generating unit 18 has a playback magnification setting unit 40, a sound source editing unit 42, a first gain setting unit 44, a second gain setting unit 46, a third gain setting unit 48, a fourth gain setting unit 50, a fifth gain setting unit 52, and an amplitude adjustment unit 56.

[0032] The playback magnification setting unit 40 sets the playback magnification α of the sound source data. The playback magnification α is calculated according to the rotation speed N [rpm] of the electric motor by the following formula (1). fa in formula (1) is the center frequency [Hz] of the first frequency band of the above-mentioned sound source.

[0033]

number

[0034] The sound source editing unit 42 edits a sound source consisting of multiple frequency components in a first frequency band with a center frequency of fa [Hz] to generate a first linked sound Sa1 consisting of multiple frequency components in a second frequency band with a center frequency of the 24th frequency of the rotation speed of the electric motor. The first linked sound Sa1 is generated by playing the sound source of the sound source data at α times the normal speed. Specifically, a digital signal string of the first linked sound Sa1 is created by selecting every (α-1) digital signal from the digital signal string of the sound source data and arranging the selected digital signals in chronological order. By repeatedly arranging the selected digital signals, a first linked sound Sa1 longer than the playback time of the original sound source data can be generated.

[0035] The first gain setting unit 44 sets a gain G1 according to the rotation speed of the electric motor. FIG. 5 is a map of the gain G1. The second gain setting unit 46 sets a gain G2 according to the accelerator pedal opening. FIG. 6 is a map of the gain G2. The third gain setting unit 48 sets a gain G3 according to the vehicle speed. FIG. 7 is a map of the gain G3. The fourth gain setting unit 50 sets a gain G4 according to the acceleration of the vehicle. FIG. 8 is a map of the gain G4. The fifth gain setting unit 52 sets a gain G5 according to the torque of the electric motor. FIG. 9 is a map of the gain G5.

[0036] The gain G2 may be set according to the load of the electric motor, and therefore the second gain setting unit 46 may set the gain G2 according to the torque of the electric motor, etc., instead of the accelerator pedal opening.

[0037] The amplitude adjustment unit 56 adjusts the amplitude of the first linked sound Sa1 generated by the sound source editing unit 42 based on the gains G1 to G5, and outputs the adjusted amplitude as the final first linked sound Sa1.

[0038] The second linked sound generation unit 20 differs from the first linked sound generation unit 18 in that the playback magnification α is calculated by the following formula (2) in the playback magnification setting unit 40, but the other configurations are the same as those of the first linked sound generation unit 18.

[0039]

number

[0040] [Background sound generation section configuration] 10 is a block diagram showing the configuration of the first background sound generation unit 22. The first background sound generation unit 22 has a playback magnification setting unit 58, a sound source editing unit 60, a first gain setting unit 62, a second gain setting unit 64, a third gain setting unit 66, a fourth gain setting unit 68, a fifth gain setting unit 70, and an amplitude adjustment unit 74.

[0041] The playback magnification setting unit 58 sets a playback magnification β of the sound source data. The playback magnification β is calculated according to the center frequency f1 [Hz] of the first background sound Sb1 by the following formula (3).

[0042]

number

[0043] The sound source editing unit 60 edits a sound source consisting of multiple frequency components in a first frequency band with a center frequency of fa [Hz] to generate a first background sound Sb1 consisting of multiple frequency components in a third frequency band with a center frequency of f1 [Hz]. The first background sound Sb1 is generated by playing the sound source of the sound source data at β times the normal speed. Specifically, a digital signal sequence of the second background sound Sb2 is created by selecting every (β-1) digital signal from the digital signal sequence of the sound source data and arranging the selected digital signals in chronological order. By repeatedly arranging the selected digital signals, it is possible to generate a first background sound Sb1 that is longer than the playback time of the original sound source data.

[0044] The first gain setting unit 62 sets a gain G1 according to the rotation speed of the electric motor. The gain G1 is set based on the map of FIG. 5 described above. The second gain setting unit 64 sets a gain G2 according to the accelerator pedal opening. The gain G2 is set based on the map of FIG. 6 described above. The third gain setting unit 66 sets a gain G3 according to the vehicle speed. The gain G3 is set based on the map of FIG. 7 described above. The fourth gain setting unit 68 sets a gain G4 according to the acceleration of the vehicle. The gain G4 is set based on the map of FIG. 8 described above. The fifth gain setting unit 70 sets a gain G5 according to the torque of the electric motor. The gain G5 is set based on the map of FIG. 9 described above.

[0045] The amplitude adjustment unit 74 adjusts the amplitude of the first background sound Sb1 generated by the sound source editing unit 60 based on the gains G1 to G5, and outputs the adjusted amplitude as the final first background sound Sb1.

[0046] The second background sound generation unit 24 differs from the first background sound generation unit 22 in that a playback magnification β is calculated by the following equation (4) in a playback magnification setting unit 58, but the other configurations are the same as those of the first background sound generation unit 22.

[0047]

number

[0048] The third background sound generation unit 26 differs from the first background sound generation unit 22 in that a playback magnification β is calculated by the following equation (5) in a playback magnification setting unit 58, but the other configurations are the same as those of the first background sound generation unit 22.

[0049]

number

[0050] The fourth background sound generation unit 28 differs from the first background sound generation unit 22 in that a playback magnification β is calculated by the following equation (6) in a playback magnification setting unit 58, but the other configurations are the same as those of the first background sound generation unit 22.

[0051]

number

[0052] [Sound effect generation processing] 11 is a flowchart of the sound effect generation process executed by the active sound effect generation device 10. The sound effect generation process is repeatedly executed at a predetermined cycle while the electric vehicle is running.

[0053] In step S1, the first interlocking sound generating unit 18 generates the first interlocking sound Sa1, and the second interlocking sound generating unit 20 generates the second interlocking sound Sa2. Then, the process proceeds to step S2.

[0054] In step S2, the first background sound generation unit 22 generates the first background sound Sb1. The second background sound generation unit 24 generates the second background sound Sb2. The third background sound generation unit 26 generates the third background sound Sb3. The fourth background sound generation unit 28 generates the fourth background sound Sb4. Then, the process proceeds to step S3.

[0055] In step S3, the sound effect generation unit 30 generates the sound effect Sc, and then ends the sound effect generation process.

[0056] In addition to the above disclosure, the following notes are also disclosed.

[0057] (Appendix 1) An active sound effect generating device (10) that generates a sound effect (Sc) from a speaker (12) provided in a vehicle driven by an electric motor includes a memory unit (16) that stores information on a sound consisting of a plurality of frequency components in a first frequency band as sound source data, a linked sound generating unit (18) that generates, from the sound source data, a sound consisting of a plurality of frequency components in a second frequency band corresponding to the rotation speed of the electric motor as a linked sound, and a sound effect generating unit (30) that uses the linked sound to generate the sound effect to be generated from the speaker. With this configuration, the size of the sound source data can be reduced.

[0058] (Appendix 2) The active sound effect generating device of appendix 1 may further include a background sound generating unit (22) that generates a sound consisting of a plurality of frequency components in a third predetermined frequency band as background sound from the sound source data, and the sound effect generating unit may generate the sound effect using the linked sound and the background sound. With this configuration, the size of the sound source data can be reduced.

[0059] (Appendix 3) In the active sound effect generating device described in Supplementary Note 1, the sound effect generating unit may change the amplitude of the sound effect in accordance with the load of the electric motor. With this configuration, a sound effect corresponding to the load of the electric motor can be generated.

[0060] (Appendix 4) In the active sound effect generating device described in Supplementary Note 1, the sound effect generating unit may change the amplitude of the sound effect in accordance with a vehicle speed. With this configuration, a sound effect corresponding to the vehicle speed can be generated.

[0061] (Appendix 5) In the active sound effect generating device described in Supplementary Note 1, the sound effect generating unit may change the amplitude of the sound effect in accordance with the acceleration of the vehicle. With this configuration, a sound effect corresponding to the acceleration can be generated.

[0062] (Appendix 6) A control method for an active sound effect generating device that generates sound effects from a speaker provided in a vehicle driven by an electric motor, the control method includes a linked sound generating step of generating a linked sound, which is a sound composed of a plurality of frequency components in a second frequency band corresponding to the rotation speed of the electric motor, from sound source data that is information on a sound composed of a plurality of frequency components in a first frequency band, as a linked sound, and a sound effect generating step of generating the sound effect using the linked sound. With this configuration, the size of the sound source data can be reduced.

[0063] The present invention is not limited to the above disclosure, and various configurations can be adopted without departing from the gist of the present invention. [Explanation of symbols]

[0064] 10...Active sound effect generating device 12...Speaker 16...Storage unit 18...First interlocking sound generation unit (interlocking sound generation unit) 22...first background sound generation unit (background sound generation unit) 30...sound effect generation unit

Claims

1. An active sound effect generating device that generates sound effects from a speaker provided in a vehicle driven by an electric motor, a storage unit that stores information on a sound composed of a plurality of frequency components in a first frequency band as sound source data; a linked sound generating unit that generates, from the sound source data, a sound composed of a plurality of frequency components in a second frequency band corresponding to the rotation speed of the electric motor as a linked sound; a sound effect generating unit that generates the sound effect to be emitted from the speaker by using the linked sound; An active sound effect generating device having the above structure.

2. 2. The active sound effect generating device according to claim 1, a background sound generating unit that generates a sound consisting of a plurality of frequency components in a predetermined third frequency band from the sound source data as a background sound, The sound effect generation unit generates the sound effect by using the linked sound and the background sound.

3. 2. The active sound effect generating device according to claim 1, The sound effect generation unit changes an amplitude of the sound effect in accordance with a load on the electric motor.

4. 2. The active sound effect generating device according to claim 1, The sound effect generating unit is an active sound effect generating device that changes an amplitude of the sound effect in accordance with a vehicle speed.

5. 2. The active sound effect generating device according to claim 1, The sound effect generation unit changes an amplitude of the sound effect in accordance with an acceleration of the vehicle.

6. A method for controlling an active sound effect generating device that generates sound effects from a speaker provided in a vehicle driven by an electric motor, comprising the steps of: a linked sound generating step of generating, as a linked sound, a sound composed of a plurality of frequency components in a second frequency band corresponding to a rotation speed of the electric motor from sound source data which is information on a sound composed of a plurality of frequency components in a first frequency band; a sound effect generating step of generating the sound effect using the linked sound; A control method for an active sound effect generating device comprising the steps of:

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