Sound loudness simulation method

Abstract

To inhibit a load due to calculation for specifying a transmission path from becoming excessively high.SOLUTION: In gap specification processing of a step S13, an execution device specifies a gap of a skeleton component located between a sound source and a specified position on the basis of body information of a vehicle. In path specification processing of a step S14, the execution device specifies a transmission path of sound from the sound source to the specified position. In the path specification processing, the execution device specifies a line segment from the sound source to the gap and a line segment from the gap to the specified position as one transmission path. The execution device calculates a distance from the sound source to the specified position through the gap as a distance of the transmission path. In estimation processing of a step S16, the execution device estimates the loudness of sound reaching the specified position from the sound source on the basis of an attenuation amount corresponding to the distance of the transmission path specified in the path specification processing.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention is a method for simulating sound loudness. [Background technology]

[0002] Patent Document 1 describes a simulation device that estimates the loudness of sound. In a space where a three-dimensional model is placed, the simulation device identifies a path from a sound source, reflected by a reflecting surface, to a predetermined specified position as a transmission path. The simulation device then estimates the loudness of the sound at the specified position based on the distance and reflectance of the identified transmission path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3258148 Summary of the Invention [Problem to be solved by the invention]

[0004] In a simulation device such as that described in Patent Document 1, when a vehicle is used as a simulation target, the calculations for identifying the reflecting surfaces on the vehicle may become complicated, which may result in an excessively heavy calculation load for identifying the propagation path. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention is a simulation method executed by a computer, which uses a vehicle equipped with a sound source as a simulation target and estimates the loudness of sound that will reach a predetermined specified position outside the vehicle from a sound source located inside the vehicle. The computer executes a gap identification process that identifies gaps in frame parts located between the sound source and the specified position based on body information of the vehicle, a path identification process that identifies a transmission path of the sound from the sound source to the specified position, and an estimation process that estimates the loudness of the sound that will reach from the sound source to the specified position based on an attenuation amount corresponding to the distance of the transmission path identified in the path identification process. In the path identification process, a line segment from the sound source to the gap and a line segment from the gap to the specified position, which include the gap, are identified as a single transmission path, and the distance from the sound source to the specified position via the gap is calculated as the distance of the transmission path. [Effects of the Invention]

[0006] According to the above configuration, it is possible to prevent the load of calculations for identifying a propagation path from becoming excessively high. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of the estimation system. [Figure 2] FIG. 2 is a schematic diagram of the vehicle being simulated. [Figure 3] FIG. 3 is a flowchart showing the simulation method. [Figure 4] FIG. 4 is a schematic diagram showing the transmission path TR. [Figure 5] FIG. 5 is a flowchart showing the details of the calculation process. [Figure 6] FIG. 6 is a flowchart showing the details of the estimation process. DETAILED DESCRIPTION OF THE INVENTION

[0008] (One embodiment) An example of a sound volume simulation method applied to a simulation device will be described below with reference to the drawings.

[0009] <System Overview> As shown in FIG. 1, the estimation system 10 includes an input device 20, a simulation device 30, and an output device 40.

[0010] When a user operates the input device 20, the input device 20 inputs a signal associated with the operation to the simulation device 30. Specifically, when a user operates the input device 20, the input device 20 inputs, to the simulation device 30, the vehicle type VT of the vehicle 50 to be simulated and sound source information SS, which is information indicating the volume of sound emitted by a sound source 60 (described later).

[0011] The output device 40 outputs the information acquired from the simulation device 30 as an image or the like. Specifically, when the output device 40 acquires an estimated value EV, which is the loudness of the sound estimated from the simulation device 30, the output device 40 outputs an image including text indicating the estimated value EV. The input device 20 and the output device 40 are realized by, for example, a touch display.

[0012] The simulation device 30 is a computer. The simulation device 30 includes a CPU (execution device 31), a peripheral circuit 32, a RAM 33, a storage device 34, and a bus 35. The bus 35 connects the execution device 31, the peripheral circuit 32, the RAM 33, and the storage device 34 so that they can communicate with each other. The execution device 31 processes information by executing various programs stored in the storage device 34. The peripheral circuit 32 includes a circuit that generates a clock signal that regulates internal operation, a power supply circuit, a reset circuit, etc. The RAM 33 stores data generated by the execution device 31 during execution. The storage device 34 stores a sound loudness simulation program SP executed by the execution device 31. The storage device 34 stores vehicle information VI. The vehicle information VI includes body information including data on the body shape and component parts of a vehicle 50 to be simulated. The body information is three-dimensional CAD data that differs for each vehicle type VT. The vehicle information VI includes information indicating the position of a sound source 60 in the vehicle 50. The vehicle information VI includes information indicating a predetermined specified position P1 outside the vehicle 50. The vehicle information VI includes a correction value that is predetermined for each vehicle type VT.

[0013] <Simulation target> As shown in FIG. 2, a vehicle 50 to be simulated has a plurality of skeleton parts 51. Gaps 52 exist between the plurality of skeleton parts 51. The body information of the vehicle 50 includes information indicating the gaps 52. The body information of the vehicle 50 is, for example, information indicating the skeleton parts 51 that make up the body-in-white of the vehicle 50. The position of the gaps 52 differs for each vehicle type VT of the vehicle 50. The gaps 52 include, for example, the space of a hole that passes through one skeleton part 51, and a space between two locations where the two skeleton parts 51 are joined by spot welding or the like where the two skeleton parts 51 are not joined.

[0014] The vehicle 50 has a sound source 60. That is, the sound source 60 is mounted on the vehicle 50. The sound source 60 is located inside the vehicle 50. The sound source 60 is, for example, an internal combustion engine of the vehicle 50. When the vehicle 50 is viewed from above, the specified position P1 is determined as a position that is a predetermined distance away from a predetermined point on the vehicle 50. For example, when the vehicle 50 is viewed from above, the specified position P1 is determined as a position that is a predetermined distance to the right in the left-right direction W of the vehicle 50 from the center of gravity of a tire that is located on the right side in the left-right direction W of the vehicle 50 and in front in the front-rear direction L.

[0015] <Simulation method> When the execution device 31 receives a signal from the input device 20 by a user's operation indicating that a sound loudness simulation method is to be started, the execution device 31 starts executing the sound loudness simulation program SP.

[0016] 3, when the execution device 31 starts executing the sound loudness simulation program SP, the execution device 31 first starts the processing of step S11. In step S11, the execution device 31 determines whether or not the vehicle type VT has been acquired. Specifically, the execution device 31 determines whether or not the vehicle type VT of the vehicle 50 to be simulated has been acquired from the input device 20 by a user operation. If the simulation device 30 has not acquired the vehicle type VT (S11: NO), the execution device 31 repeats the processing of step S11. On the other hand, if the simulation device 30 has acquired the vehicle type VT (S11: YES), the execution device 31 proceeds to the processing of step S12.

[0017] In step S12, the executing device 31 determines whether or not it has acquired sound source information SS. Specifically, the executing device 31 determines whether or not it has acquired sound source information SS of the vehicle 50 to be simulated from the input device 20 through a user operation. The sound source information SS is information indicating the loudness of the sound emitted by the sound source 60. For example, the loudness of the sound is indicated by sound pressure. The sound source information SS is a value determined, for example, by a test conducted in advance based on the results of measuring the loudness of the sound without the sound source 60 being installed in the vehicle 50. If the simulation device 30 has not acquired the sound source information SS (S12: NO), the executing device 31 repeats the process of step S12. On the other hand, if the simulation device 30 has acquired the sound source information SS (S12: YES), the executing device 31 proceeds to step S13.

[0018] In step S13, the execution device 31 executes a gap identification process. In the gap identification process, the execution device 31 identifies a gap 52 in a skeleton part 51 located between the sound source 60 and a specified position P1, based on body information of the vehicle 50.

[0019] Here, the axis along which the line segment connecting the center of gravity of the sound source 60 and the specified position P1 extends is defined as the X-axis. The axis perpendicular to the X-axis is defined as the Y-axis. The execution device 31 refers to the body information of the vehicle 50 and selects, as target parts, skeleton components 51 that are located between a line that passes through the center of gravity of the sound source 60 and is parallel to the Y-axis, and a line that passes through the specified position P1 and is parallel to the Y-axis. Next, the execution device 31 refers to the body information of the vehicle 50 and identifies gaps 52 between the selected target multiple skeleton components 51. As a result, the execution device 31 identifies the gaps 52 through a gap identification process. After that, the execution device 31 proceeds to step S14.

[0020] In step S14, the execution device 31 performs a path identification process. In the path identification process, the execution device 31 identifies a sound transmission path TR from the sound source 60 to the specified position P1. The execution device 31 identifies one transmission path TR for one gap 52 identified in the gap identification process.

[0021] 4, the execution device 31 calculates a first line segment L1 and a second line segment L2 for the identified gap 52. The first line segment L1 is a line segment from the center of gravity of the sound source 60 to the identified gap 52. The second line segment L2 is a line segment from the gap 52 to a specified position P1. In this embodiment, the execution device 31 calculates each line segment as a line segment that passes through the center of gravity of the gap 52.

[0022] Next, the execution device 31 calculates one transfer path TR as a continuous path connecting the end of the first line segment L1 on the gap 52 side and the end of the second line segment L2 on the gap 52 side. That is, in the path identification process, the execution device 31 identifies the line segment from the sound source 60 to the gap 52 and the line segment from the gap 52 to the specified position P1 as one transfer path TR.

[0023] Next, the execution unit 31 calculates the distance of one transfer path TR. The execution unit 31 calculates the sum of the length of the first line segment L1 and the length of the second line segment L2 as the distance of one transfer path TR. In other words, the execution unit 31 calculates the distance from the sound source 60 through the gap 52 to the specified position P1 as the distance of the transfer path TR.

[0024] Next, the execution device 31 calculates the distances of the transfer paths TR for all of the gaps 52 identified in the gap identification process. Then, a predetermined number of transfer paths TR are selected in order from the transfer path TR with the shortest distance. For example, if the predetermined number is three, the execution device 31 identifies the transfer path TR with the shortest distance, the transfer path TR with the second shortest distance, and the transfer path TR with the third shortest distance as the transfer paths TR of the sound.

[0025] As a result, the execution device 31 identifies the sound transmission path TR through the path identification process shown in Fig. 3. After that, the execution device 31 advances the process to step S15. In step S15, the execution unit 31 performs a calculation process of the attenuation amount AA. In the calculation process, the execution unit 31 calculates the attenuation amount AA in the transfer path TR identified by the path identification process.

[0026] 5, when the calculation process begins, the execution unit 31 first performs the process of step S21 for one transfer path TR. In step S21, the execution unit 31 calculates a first distance attenuation amount AA1 according to the distance of the first line segment L1. The first distance attenuation amount AA1 is a value that increases as the distance of the first line segment L1 increases. Thereafter, the execution unit 31 proceeds to step S22.

[0027] In step S22, the execution unit 31 calculates a second distance attenuation amount AA2 corresponding to the distance of the second line segment L2. The second distance attenuation amount AA2 is a value that increases as the distance of the second line segment L2 increases. Then, the execution unit 31 proceeds to step S23.

[0028] In step S23, the execution unit 31 calculates the gap attenuation AAG when passing through the gap 52. When the gap 52 is covered by an adhesive or rubber member that is not a skeletal component 51, the gap attenuation AAG is calculated as a value according to the material of the member. When the gap 52 is not covered, the gap attenuation AAG is zero. After that, the execution unit 31 proceeds to step S24.

[0029] In step S24, the execution unit 31 calculates the attenuation AA by adding the first distance attenuation AA1, the second distance attenuation AA2, and the gap attenuation AAG. After that, the execution unit 31 ends the series of processes.

[0030] 3, the executing device 31 calculates the attenuation AA for each transfer path TR identified by the path identification process. Thus, through the calculation process, the executing device 31 calculates the attenuation AA for each transfer path TR identified by the path identification process. Thereafter, the executing device 31 proceeds to step S16.

[0031] In step S16, the execution device 31 performs an estimation process. In the estimation process, the execution device 31 estimates the loudness of the sound reaching the specified position P1 from the sound source 60 based on the attenuation AA according to the distance of the transfer path TR identified in the path identification process.

[0032] As shown in FIG. 6, when the execution of the estimation process starts, the execution device 31 first performs the process of step S31. In step S31, the execution device 31 calculates a base value BA of the sound pressure, which indicates the loudness of the sound, based on the attenuation amount AA calculated in the calculation process. Specifically, the execution device 31 first calculates the sound pressure before attenuation of each transfer path TR by dividing the sound pressure, which indicates the loudness of the sound, indicated by the sound source information SS by the number of identified transfer paths TR. Next, for each identified transfer path TR, the execution device 31 calculates the sound pressure after attenuation of each transfer path TR by subtracting the attenuation amount AA for that transfer path TR from the sound pressure before attenuation of that transfer path TR calculated by the division. Next, the execution device 31 adds up the sound pressures after attenuation of all the identified transfer paths TR to calculate a base value BA. Thereafter, the execution device 31 proceeds to the process of step S32.

[0033] In step S32, the execution unit 31 corrects the calculated base value BA to calculate the estimated loudness value EV. Specifically, the execution unit 31 calculates the estimated loudness value EV by correcting the base value BA by a correction value that is predetermined for each vehicle type VT. In this embodiment, the execution unit 31 calculates the estimated value EV by subtracting the correction value from the base value BA. The correction value is determined for each vehicle type VT based on the test results of loudness that are based on past tests. The correction value is, for example, a value determined for each vehicle type VT based on the test results of loudness that include the influence of reflective surfaces such as the frame parts 51 of the vehicle 50. Thereafter, the execution unit 31 ends the series of processes.

[0034] 3, upon completing the estimation process, the execution device 31 proceeds to step S17. In step S17, the execution device 31 outputs the estimated value EV, which is the estimated sound loudness, to the output device 40. In response, the output device 40, which has acquired the estimated value EV, displays an image including text indicating the estimated value EV. This causes the execution device 31 to end the series of processes.

[0035] (Operation of the embodiment) According to the above embodiment, the simulation device 30 identifies the transfer path TR by identifying the gaps 52 in the frame components 51, without calculating the reflecting surfaces of the frame components 51 that constitute the vehicle 50. Then, the simulation device 30 calculates an estimated value EV, which is the loudness of the sound that reaches the specified position P1 from the sound source 60, based on the attenuation AA that corresponds to the distance of the identified transfer path TR.

[0036] (Effects of the embodiment) (1-1) Due to the complex shapes of the frame components 51 that constitute the vehicle 50, when identifying the reflecting surfaces of the sound emitted from the sound source 60, the number of surfaces may be enormous and the shapes of the surfaces may be complex. According to the above embodiment, the simulation device 30 identifies the transfer path TR by identifying the gaps 52 without calculating the reflecting surfaces. The execution device 31 can determine the presence or absence of the gaps 52 by referring to the body information of the vehicle 50. Therefore, the simulation device 30 can prevent the calculation load for identifying the transfer path TR from becoming excessively high. Furthermore, in the vehicle 50, the impact of sound leaking to the outside through the gaps 52 is greater than the impact of sound that passes through the frame components 51 that constitute the body. Therefore, according to the sound loudness simulation method according to the above embodiment, the sound loudness can be estimated while preventing the calculation load of the simulation device 30 from becoming excessively high.

[0037] (1-2) According to the above embodiment, the execution device 31 further executes a calculation process. In the calculation process, the execution device 31 calculates a first distance attenuation amount AA1 corresponding to the distance of the first line segment L1, a gap attenuation amount AAG occurring when passing through the gap 52, and a second distance attenuation amount AA2 corresponding to the distance of the second line segment L2. The execution device 31 then calculates the attenuation amount AA by adding together the first distance attenuation amount AA1, the gap attenuation amount AAG, and the second distance attenuation amount AA2. This allows the execution device 31 to calculate the attenuation amount AA corresponding to the influence of the attenuation due to the distance in one transfer path TR and the attenuation occurring when passing through the gap 52. Therefore, the execution device 31 can calculate the attenuation amount AA by reflecting information about the distance and the material of the member covering the gap 52. Therefore, the simulation device 30 can improve the accuracy of calculating the estimated value EV of the sound loudness using the transfer path TR including the gap 52 compared to estimating the sound loudness without depending on the distance of the transfer path TR or the member covering the gap 52.

[0038] (1-3) According to the above embodiment, in the estimation process, the execution device 31 calculates the base value BA of the sound loudness and then corrects the base value BA with a correction value for each vehicle type VT. This allows the simulation device 30 to reflect the influence of the reflecting surface in the estimated value EV without reflecting the influence of the reflecting surface in the transfer path TR.

[0039] (1-4) According to the above embodiment, the number of identified transfer paths TR is set to a predetermined number or less. Therefore, it is possible to prevent the number of transfer paths TR calculated by the execution device 31 from becoming too large, which would result in an excessive burden on the calculation.

[0040] (Other embodiments) <Computer> According to the above embodiment, the computer that executes the simulation method for estimating sound loudness is the simulation device 30, but the computer is not limited to the simulation device 30. For example, the computer may be one that does not store the vehicle information VI. In this case, for example, the gap identification process may be performed after acquiring the vehicle information VI of the vehicle 50 of the type indicated by the vehicle type VT from the input device 20.

[0041] The simulation device 30 may be configured as a circuit including one or more processors that execute various processes according to a computer program (software). The simulation device 30 may also be configured as a circuit including one or more dedicated hardware circuits, such as an application-specific integrated circuit (ASIC), that execute at least some of the various processes, or a combination thereof. The processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer.

[0042] <Each step in the simulation method> The number of transfer paths TR identified by the simulation device 30 in the path identification process may be less than a predetermined number or may be greater than the predetermined number. For example, the simulation device 30 may identify transfer paths TR equal to the number of all gaps 52 identified in the gap identification process. Furthermore, the simulation device 30 may identify only transfer paths TR whose distances are equal to or less than a predetermined distance as sound transfer paths TR.

[0043] The calculation method of the simulation device 30 is not limited to the example of the above embodiment. For example, the execution device 31 may calculate the attenuation amount AA by adding the first distance attenuation amount AA1 and the second distance attenuation amount AA2, instead of calculating the gap attenuation amount AAG. Alternatively, for example, the execution device 31 may calculate the first distance attenuation amount AA1 by correcting it by the amount of light passing through the interior components of the vehicle 50, thereby correcting it to a larger value than before correction. On the other hand, the execution device 31 may calculate the second distance attenuation amount AA2 without correcting it to take into account the interior components, because the second line segment L2 does not pass through any components that make up the vehicle 50. Alternatively, for example, the execution device 31 may calculate the gap attenuation amount AAG based on the distance of the gap 52 in the left-right direction W of the vehicle 50. Alternatively, for example, the execution device 31 may calculate the attenuation amount AA based on the total length of the line segments that make up the transfer path TR.

[0044] The simulation device 30 does not need to perform the calculation process. For example, if the vehicle information VI has a value indicating a predetermined amount of attenuation for each transfer path TR, the simulation device 31 may obtain the attenuation amount AA by referring to the value.

[0045] The method of estimation processing by the simulation device 30 is not limited to the example of the above embodiment. For example, the execution device 31 may calculate the base value BA as the estimated value EV. Also, for example, the execution device 31 may use a value that reflects the influence of reflection from the ground on which the vehicle 50 is located as a correction value. In this case, the execution device 31 may perform correction so that the attenuation amount AA is reduced by the amount of the correction value. [Explanation of symbols]

[0046] 10...estimation system, 20...input device, 30...simulation device, 40...output device, 50...vehicle, 51...framework part, 52...gap, 60...sound source, AA...attenuation, AA1...first distance attenuation, AA2...second distance attenuation, AAG...gap attenuation, BA...base value, P1...specified position, TR...transmission path

Claims

1. The computer runs A simulation method for estimating the loudness of a sound that reaches a predetermined position outside a vehicle from a sound source located inside the vehicle, the method comprising: The computer a gap identification process for identifying a gap in a frame part located between the sound source and the specified position based on body information of the vehicle; a path identification process for identifying a propagation path of the sound from the sound source to the specified position; an estimation process for estimating the loudness of the sound reaching the specified position from the sound source based on an attenuation amount according to the distance of the transmission path identified in the path identification process; Run In the path identification process, a line segment from the sound source to the gap and a line segment from the gap to the specified position, which include the gap, are identified as one transmission path, and the distance from the sound source to the specified position via the gap is calculated as the distance of the transmission path. A method for simulating sound loudness.

2. the computer further executes a calculation process to calculate the amount of attenuation in the transfer path; In the calculation process, for one of the transmission paths identified in the path identification process, a first distance attenuation amount corresponding to the distance of the line segment from the sound source to the gap is calculated, a gap attenuation amount when passing through the gap is calculated, a second distance attenuation amount corresponding to the distance of the line segment from the gap to the specified position is calculated, and a value obtained by adding the first distance attenuation amount, the gap attenuation amount, and the second distance attenuation amount is calculated as the attenuation amount. The method for simulating sound loudness according to claim 1 .

3. In the estimation process, a base value of the loudness of the sound is calculated based on the amount of attenuation, and the calculated base value is corrected by a value predetermined for each type of vehicle, thereby estimating the loudness of the sound. The method for simulating sound loudness according to claim 1 .

4. In the route identification process, a predetermined number or less of the transmission routes are identified. The method for simulating sound loudness according to claim 1 .

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