JP2017149336A - Vehicle sound evaluation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle sound evaluation device capable of predicting and evaluating comfort and discomfort which are applied to a driver of a vehicle, a passenger of the vehicle and a peripheral environment of the vehicle by an engine sound, an air conditioner sound and various kinds of sounds generated by various kinds of components which can be heard at outside of a cabin of a vehicle such as a motor vehicle.SOLUTION: A vehicle sound evaluation device comprises: an acoustic sensor for collecting acoustic signals which are output in a cabin and outside of the cabin of a vehicle such as a motor vehicle; an acoustic signal analysis part for analyzing the acoustic signal; and a vehicle sound evaluation part for evaluating comfort of a person to the acoustic signal based on an analysis result of the acoustic signal analysis part. The acoustic signal analysis part has a function for calculating an acoustic nerve excitement pattern from an acoustic sense filter shape of a non-impaired person, and the vehicle sound evaluation part has a function for determining comfort of the acoustic signal based on the acoustic nerve excitement pattern.SELECTED DRAWING: Figure 1

Description

  The present invention relates to comfort that various sounds generated by various parts such as engine sounds, air conditioner sounds, and the like that can be heard inside and outside a vehicle such as an automobile, affect the driver, passengers, and the surrounding environment of the vehicle. The present invention also relates to a vehicle sound evaluation apparatus that predicts and evaluates discomfort.

  Various sounds such as engine sounds, door opening / closing sounds, and air conditioner sounds occur inside and outside vehicles such as automobiles, and depending on their sound quality and level, not only the driver and passengers of the vehicle but also the surroundings of the vehicle It can also cause great discomfort to the people who are.

  As for the sounds of automobile engine sounds and sound mufflers (mufflers), the sound pressure level and frequency components of those sounds are analyzed during the design, prototyping, and manufacturing process of the relevant car manufacturer to evaluate the comfort of the sound. In general, work processes such as shipping after being performed have been performed.

  The sound pressure level and frequency component analysis are similarly performed on the sound of the air conditioner in the passenger compartment. In addition, some automobile manufacturers will analyze the sounds generated when opening and closing the doors of automobiles, the rubbing sounds of seats in the passenger compartment, and the frictional sounds. Work processes have been implemented.

  For these frequency component analyses, commonly used FFT analysis and octave band analysis have been used. After the analysis results were examined together with the sound pressure level, the final decision on comfort was made by relying on the intuition and feelings of many years of experience from developers and engineers.

  Patent Document 1 discloses a method for detecting an acoustic space characteristic in a cabin space of a motor vehicle by transmitting a test sound and analyzing a received evaluation sound by using an effective sound transmission device. The test sound (T; TS) is transmitted to the psychoacoustic masking area (6; 7) of the effective sound, in particular for detecting acoustic space characteristics in the cabin space of a motor vehicle A method and apparatus is disclosed.

  In Patent Document 2, an extraction unit that extracts a tangent line representing a fluctuation state with respect to a time axis of a detection signal detected by a detection unit that detects at least one sound inside and outside the vehicle, and extracted by the extraction unit Based on the modulation signal generated by the generation unit that analyzes the frequency of the envelope and generates a modulation signal in which the phase of the specific periodic component is shifted by a predetermined phase from the analysis result, the inside and outside of the vehicle There is disclosed a vehicle noise / sound quality control device including sound generation signal generation means for generating a sound generation signal for sound generation from at least one of the sound generation means.

  In Patent Document 3, the measured evaluation sound to be evaluated is subjected to order analysis, and the inclination of the straight line with respect to the sound pressure level of the order component serving as the fundamental tone of the evaluation sound subjected to the order analysis and the harmonic component thereof is analyzed. And calculating the difference between the analysis inclination angle x and the ideal inclination angle xr stored in advance, the total value NL0.5 of the 0.5th-order pitch background noise, and the main order level summation value S. A vehicle sound quality evaluation apparatus and a vehicle sound quality evaluation method for obtaining a sense of harmony level using a sense of harmony quantitative evaluation formula formed including a term are disclosed.

  Patent Document 4 discloses an air-conditioning sound data collection procedure for collecting air-conditioning sound data to be evaluated in an air-conditioning sound quality evaluation method for quantitatively evaluating the sound quality of air-conditioning sound based on the collected air-conditioning sound data. A sharpness calculation procedure that draws a loudness spectrum, which is the loudness of the air-conditioning sound data, finds the center of gravity of the spectrum area, and calculates the sharpness that becomes higher as the center of gravity position is higher, is calculated. A sound quality evaluation method and a sound quality evaluation system including a sound quality evaluation procedure for evaluating a sound quality based on a person's perception of what kind of feeling of air conditioning sound is defined as a psychoacoustic evaluation value. .

  Patent Document 5 discloses an acoustic sensor that collects an acoustic signal emitted from a product or a part for manufacturing the product, an acoustic signal analysis unit that analyzes the acoustic signal, and an analysis result of the acoustic signal analysis unit. An abnormal sound determination device comprising an acoustic signal determination unit for determining whether the acoustic signal is a normal acoustic signal or an abnormal acoustic signal, wherein the acoustic signal analysis unit calculates an auditory nerve excitation pattern from a hearing filter shape of a normal hearing person There is disclosed an abnormal sound determination device in which the acoustic signal determination unit has a function of determining whether the acoustic signal is a normal acoustic signal or an abnormal acoustic signal based on the auditory nerve excitation pattern.

Japanese Patent Laid-Open No. 2001-69600 JP 2007-233309 A JP 2008-298474 A JP 2009-36603 JP 2009-175077

  The problem to be solved is that various sounds generated by various parts, such as engine sounds, air conditioner sounds, etc. that can be heard inside and outside the vehicle, such as automobiles, are generated by the driver, passengers, and the surrounding environment of the vehicle. It is intended to provide a device for predicting and evaluating the comfort and discomfort etc. exerted on the body.

  In patent document 1, in order to detect the acoustic space characteristic in the cabin space in an automobile, a test sound is additionally transmitted using a device that transmits an effective sound (for example, music), and the test sound is effective. The sound quality in the acoustic system in the motor vehicle is optimized by being transmitted to the sound psychoacoustic masking area (screening area), but this is only an automobile using psychoacoustic masking. The purpose is to improve the sound quality of the both acoustic systems, and it is impossible to judge the comfort of various sounds generated by various parts such as engine sounds, air conditioner sounds and the like that can be heard inside and outside the interior of a vehicle such as an automobile. In addition, the concept of psychoacoustic masking is very vague, and analysis that takes into account the mechanism of the human auditory organ has not been performed at all, so the degree of improvement in sound quality cannot be predicted. It was.

  In Patent Document 2, a tangent line with respect to a time axis of a detection signal detected by a detecting means for detecting at least one of the sound inside and outside the vehicle is extracted, the frequency of the tangential line is analyzed, and the identification result is specified. Vehicle noise and sound quality control is performed by generating and generating a modulated signal in which the phase of the periodic component is shifted by a predetermined phase. However, as a method of frequency analysis, an analysis method based on a commonly used physical quantity such as FFT is used, and analysis taking into account the mechanism of the human auditory organ or the like is not performed at all. Therefore, there is a problem that the processing is performed without knowing the comfort of the sound quality of the vehicle noise.

  In Patent Document 3, the sound quality of a vehicle is evaluated by performing a degree analysis on the measured evaluation sound to be evaluated and quantitatively evaluating the sense of harmony of the evaluation sound. The sense of cooperativeness is based on evaluation characteristic (“comfortable”, “crisp”, “linear”) and acoustic characteristic data such as frequency spectrum of sound. However, this is based solely on the subjective evaluation results of the tester or subject performing the test, and no analysis or the like taking into account the mechanism of the human auditory organ has been performed. Therefore, there is a problem that the comfort of the sound quality of the vehicle is based on the subjective evaluation result, and it is difficult to make a quantitative determination.

  In Patent Document 4, although it is a simple evaluation method using one psychoacoustic evaluation amount (sharpness), it is possible to appropriately evaluate the overall comfort feeling of the air-conditioning sound based on the human auditory function. An air quality sound quality evaluation method and sound quality evaluation system are disclosed. However, the frequency analysis technique that is the basis for calculating the sharpness is based on a conventional physical band-pass filter or the like, and no analysis or the like taking into account the mechanism of the human auditory organ has been performed. Therefore, the evaluation of the comfort and the like of the air-conditioning sound is based on the frequency component analysis result that is a physical quantity, and there is a problem that the evaluation of the comfort of the sound quality and the prediction of the improvement effect cannot be made accurately.

  In Patent Document 5, an acoustic signal is analyzed using an acoustic analysis method closest to a human auditory mechanism in order to detect an abnormal sound that has been discriminated by an experienced engineer by the device, and an abnormal sound determination is performed based on the result. It is carried out. Here, the analysis is based on the auditory nerve excitation pattern, which is an analysis method that takes into account the mechanism of the human auditory organ, etc., but this is only for the purpose of detecting abnormal sounds generated during the manufacturing process. Predicting and evaluating the comfort and discomfort of various sounds produced by various parts, such as engine sounds, air conditioner sounds, etc., that can be heard inside and outside the vehicle, on the driver, passengers and surrounding environment of the vehicle There is no suggestion or disclosure regarding the method.

  In the present invention, the comfort of various sounds generated by various parts such as engine sounds, air conditioner sounds, etc. that can be heard inside and outside a vehicle such as an automobile, on the driver, passengers, and the surrounding environment of the vehicle. In addition, an uncomfortable feeling or the like is analyzed using an acoustic analysis method closest to the human auditory mechanism, and vehicle sound evaluation is performed based on the result.

  Specifically, an acoustic sensor that collects an acoustic signal emitted outside a vehicle interior of a vehicle such as an automobile, an acoustic signal analysis unit that analyzes the acoustic signal, and the analysis result of the acoustic signal analysis unit A vehicle sound evaluation apparatus for evaluating human comfort with respect to an acoustic signal, wherein the acoustic signal analysis unit has a function of calculating an auditory nerve excitation pattern from a hearing filter shape of a normal hearing person, and the acoustic signal determination unit It was set as the structure which has the function to determine the comfort of the said acoustic signal based on an excitement pattern. As a result, the evaluation of vehicle sound quality and comfort, which has traditionally relied on intuition and sensation based on many years of experience, such as physical indicators and workers who have nothing to do with human hearing, is now closer to human sensation. This makes it possible to accurately evaluate the comfort of sound quality and predict the improvement effect.

  If the acoustic signal in this case is an engine sound of a car, a vehicle capable of accurately predicting and evaluating the comfort, discomfort, etc. exerted by the engine sound of the vehicle on the driver, passengers and surrounding environment of the vehicle It is possible to configure a sound evaluation apparatus.

  Further, if the acoustic signal in this case is an acoustic signal emitted from the muffler of an automobile, the comfort that the engine sound of the vehicle substantially has on the driver, passengers, surrounding environment of the vehicle, and the like It is possible to configure a vehicle sound evaluation device that can accurately predict and evaluate discomfort and the like, and can evaluate the performance of the muffler based on the comfort that humans feel.

  Further, if the acoustic signal in this case is an air conditioner sound in the vehicle interior, vehicle sound evaluation that can accurately predict and evaluate the comfort and discomfort that the driver and passengers feel in the vehicle interior of the vehicle It is possible to configure the device.

  Further, if the acoustic signal in this case is an opening / closing sound of an automobile door, vehicle sound evaluation that can accurately predict and evaluate the comfort and discomfort that the driver and passengers feel when opening and closing the door of the vehicle. It is possible to configure the device.

  Furthermore, if the acoustic signal in this case is a rubbing sound or friction sound of a seat in the vehicle interior, the vehicle sound that can accurately predict and evaluate the comfort and discomfort that the driver and passengers feel in the vehicle interior. An evaluation device can be configured.

  The vehicle sound evaluation apparatus according to the present invention has been used to evaluate the sound quality and comfort of a vehicle sound that has conventionally relied on intuition and sensation based on many years of experience such as physical indicators and workers who are not related to human hearing. By analyzing using the acoustic nerve excitation pattern, which is the analysis method closest to the mechanism, it is possible to predict and evaluate comfort, discomfort, and the like on the driver, passengers, and the surroundings of the vehicle.

  This makes it possible to predict the comfort and discomfort felt by the driver, passengers and people living in the surrounding environment of various sounds emitted from the vehicle during operation of the vehicle such as an automobile. Thus, it is possible to improve the comfort of people inside and outside the vehicle.

  In addition, the comfort of various sounds emitted from vehicles such as automobiles can be predicted in advance, so noise pollution damage caused by sounds emitted from vehicles, etc., and the feeling of fatigue felt by drivers and passengers when boarding It is also possible to contribute to mitigation.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings. In the following description, components having the same function are denoted by the same reference numerals, and repeated description thereof is omitted.

  FIG. 1 is a block diagram of a system according to an embodiment of the present invention, which includes an acoustic sensor 1, an acoustic filter bank 4, an acoustic excitation pattern calculation unit 5, an acoustic signal analysis unit 2, and a vehicle sound evaluation unit 3.

  The acoustic sensor 1 is composed of a microphone or the like. Installed anywhere in the vehicle interior or exterior where the sound emitted from the vehicle can be picked up, sounds generated by engine sounds and silencers (mufflers), sound of air conditioners in the vehicle interior, door opening and closing Collects sounds that are sometimes generated, rubbing sounds of seats in the passenger compartment, friction sounds, and the like.

  The acoustic signal analysis unit 2 passes the acoustic signal collected by the acoustic sensor 1 through the auditory filter bank 4 of a normal hearing person, and then uses the acoustic nerve excitation pattern calculation unit 5 to convert the acoustic nerve excitation pattern (excitation pattern) of the acoustic signal. calculate.

  Here, the auditory filter is a technique for modeling the function of the “cochlea” in the inner ear, which plays the most important role in human peripheral auditory organs, with an electrical filter.

  A human cochlea has a function of analyzing a frequency component contained in an acoustic signal that has entered the ear and transmitting it to the auditory nerve. It is known that a frequency analysis function equivalent to that of a human auditory peripheral organ can be realized by simulating this function with an auditory filter bank composed of a plurality of bandpass filters.

  FIG. 2 is a schematic diagram of the auditory filter bank 4, where the horizontal axis represents frequency and the vertical axis represents sound intensity. Here, as an example, a case where a pure tone having a specific frequency is input is illustrated.

  The shape (frequency characteristic) of each auditory filter constituting the auditory filter bank 4 is unique to a human cochlea. Known filter model functions for simulating the frequency analysis function of a human cochlea include a roex filter, a gamma tone filter, and a gamma chirp filter.

  Further, it is known that the bandwidth of the auditory filter changes for each frequency of the input sound, and it is clarified by Non-Patent Document 1 that a normal hearing person can be approximated by a function of the frequency shown in Equation (1). Yes.

_{ERB (f C) = 24.673 (} 4.368f C / 1000 + 1) ··· (1)

In equation (1), fc is the center frequency of the auditory filter, and ERB is its bandwidth (Equivalent Rectangular Bandwidth).
BR Glasberg, BCJ Moore, "Derivation of auditory filter shapes from notched-noise data," Hear. Res. 47, 103-138 (1990)

  The auditory nerve excitation pattern (excitation pattern) is a frequency distribution of the amount of nerve excitation that is output to the auditory nerve as a result after the input sound is frequency-analyzed by the cochlea, and this is the frequency distribution of the frequency using the auditory filter bank 4. It can be calculated approximately as a function.

  FIG. 3 shows a schematic diagram of the auditory nerve excitation pattern calculation when a pure tone having a specific frequency is input to the auditory filter bank 4. Since the passing amount of the auditory filter A 1 is a 1 with respect to the input pure sound, the output value a 2 is obtained. Similarly, since the output values b, c, d, e, and f are obtained from the auditory filters B, C, D, E, and F, respectively, if these output values are plotted, an auditory nerve excitation pattern is obtained. Previous research reports have confirmed that this auditory nerve excitation pattern is consistent with physiological data from human cochlea and auditory nerves.

  The right figure of FIG. 4 shows the result of the acoustic nerve excitation pattern (excitation pattern) obtained by analyzing the actual engine sound of the automobile by the acoustic signal analysis unit 2 of the present invention. As a general conventional analysis result, the FFT analysis is shown on the left and the LPC analysis is shown on the center. In all cases, the horizontal axis represents frequency, and the vertical axis represents relative intensity [dB].

Here, the roex (p, r) filter is used as the model function of the auditory filter. The roex (p, r) function is a function expressed by equation (2), where f _C is the center frequency of the auditory filter, Δf is the difference from the center frequency, p is the filter bandwidth, and r is the filter dynamic range. And is one of the representative model functions of the auditory filter.

_{W (Δf / f C) =} (1-r) (1 + pΔf / f C) e p Δ f / fC + r ··· (2)

  In the result of the FFT analysis in the left figure of FIG. 4, a specific peak is recognized in the low frequency range, but this is a peak recognized in almost all engine sounds. From this result, the sound quality of the engine sound is evaluated. It is difficult.

  In the result of the LPC analysis in the center diagram of FIG. 4, the frequency spectrum envelope (envelope) of the engine sound is displayed. Here, in the engine sound, no feature on the frequency component other than the specific peak in the low frequency range recognized by the FFT analysis is recognized.

  The results in the right figure of Fig. 4 are the results of analysis by modeling the function of the "cochlea" in the inner ear with an electrical filter. Therefore, humans are more likely than the physical analysis methods FFT analysis and LPC analysis. If there is a sharp peak in the characteristics, or if the high frequency component is strong, there is a high possibility that the human will feel uncomfortable.

  In the excitation pattern shown in the right diagram of FIG. 4 according to the present invention, a characteristic component is recognized in the frequency region around the dotted line. There are two peaks at 500Hz-1kHz, which can be annoying to those who hear these sounds. In addition, it can be seen that the components around 2kHz-5kHz are strong, and some uncomfortable sound components are included.

  The vehicle sound evaluation unit 3 detects peaks such as those seen at 500Hz-1kHz in the left figure of FIG. 4 from the excitation pattern analysis results, detects the intensity of components in the high frequency region, and determines the sharpness and height of the peaks. It is determined from the intensity in the frequency domain whether the sound is unpleasant.

  In actual operation, we conduct auditory psychological experiments on various engine sounds in advance to obtain subjective evaluations and introspection reports of subjects, and a database of excitation pattern characteristics that may give a feeling of comfort or discomfort in particular Is preferably recorded in the vehicle sound evaluation unit 3.

  Then, the engine sound of the vehicle collected by the acoustic sensor 1 is analyzed by the acoustic signal analysis unit 2, and the characteristics of the collected acoustic signal and the characteristics recorded in the database are analyzed by the vehicle sound evaluation unit 3. The comfort is determined by obtaining the difference or Euclidean distance, or the difference from the comfortable sound (unpleasant sound) is determined using a method such as pattern matching.

  FIG. 5 illustrates a state in which the sound of the engine under development is analyzed by the vehicle sound evaluation apparatus according to the present invention. The acoustic sensor 1 is a microphone, and the acoustic signal analysis unit 2 and the vehicle sound evaluation unit 3 are incorporated as program software in the tablet terminal. With such a configuration, it is possible to frequently evaluate engine sound comfort in a short time at a development site or the like.

  In this embodiment, the sound to be analyzed is the engine sound of the automobile. However, the user feels more comfortable to analyze the sound through the muffler (muffler) than to analyze the sound of the engine itself. It's easy to do. Therefore, this vehicle sound evaluation apparatus is useful also for the performance test of a silencer.

  FIG. 6 shows a state in which the acoustic sensor 1 is arranged inside or outside the vehicle. In this state, if the acoustic signal analysis unit 2 and the vehicle sound evaluation unit 3 are configured in the form of a dedicated analysis device, a tablet terminal, a PC, or the like, it is possible to analyze sounds inside and outside the vehicle.

  In the case of the form as shown in FIG. 6, as the sound emitted from the vehicle, the sound of the air conditioner in the vehicle interior, the door opening / closing sound of the vehicle, the cloth rubbing sound or the friction sound of the seat in the vehicle interior, and the like should be evaluated in the same manner. Is possible.

  Further, the acoustic sensor 1 is installed outside the vehicle interior, the acoustic signal analysis unit 2 and the vehicle sound evaluation unit 3 are installed at any position in the vehicle interior, and the result of the vehicle sound evaluation unit 3 can be clearly shown to the driver or passengers. In this case, not only the manufacturer of a vehicle such as an automobile but also the user of the automobile can be notified of the evaluation result of the sound emitted by the vehicle.

  For example, a configuration in which the acoustic signal analysis unit 2 and the vehicle sound evaluation unit 3 are incorporated in the car navigation device, the evaluation result of the vehicle sound evaluation unit 3 is clearly shown on the monitor of the car navigation device, and the driver or the If the passenger is informed of the evaluation result, the user can know the comfort and discomfort of the sound generated by the vehicle.

  The user can use the comfort and discomfort as judgment material for purchase at the time of test drive at the time of purchasing an automobile. Moreover, it is also possible to configure the apparatus so that the user can objectively determine the stress and feeling of fatigue caused by the sound generated by the automobile from the comfort of the passenger compartment during traveling.

System block diagram Schematic diagram of auditory filter bank Schematic diagram of calculation of acoustic nerve excitation pattern (excitation pattern) Example of actual measurement data Example of engine sound evaluation Schematic diagram when the acoustic sensor 1 is arranged inside and outside the car interior

  DESCRIPTION OF SYMBOLS 1 ... Acoustic sensor, 2 ... Acoustic signal analysis part, 3 ... Vehicle sound evaluation part, 4 ... Auditory filter bank, 5 ... Auditory nerve excitation pattern calculation part.

Claims (6)

An acoustic sensor that collects acoustic signals emitted from inside and outside of a vehicle such as an automobile, an acoustic signal analysis unit that analyzes the acoustic signals, and a human signal for the acoustic signals based on an analysis result of the acoustic signal analysis unit A vehicle sound evaluation apparatus comprising a vehicle sound evaluation unit for evaluating comfort, wherein the acoustic signal analysis unit has a function of calculating an auditory nerve excitation pattern from a hearing filter shape of a normal hearing person, and the vehicle sound evaluation unit A vehicle sound evaluation apparatus having a function of determining comfort of the acoustic signal based on an auditory nerve excitation pattern. The vehicle sound evaluation apparatus according to claim 1, wherein the acoustic signal is an automobile engine sound. The vehicle sound evaluation apparatus according to claim 1, wherein the acoustic signal is an acoustic signal emitted from a muffler of an automobile. The abnormal sound determination apparatus according to claim 1, wherein the acoustic signal is an air conditioner sound in an automobile interior. 2. The vehicle sound evaluation apparatus according to claim 1, wherein the acoustic signal is an opening / closing sound of an automobile door. The vehicle sound evaluation apparatus according to claim 1, wherein the acoustic signal is a rubbing sound or a friction sound of a seat in a vehicle interior.