阅读说明：本技术 马达噪声掩蔽 (Motor noise masking ) 是由 A.戈梅兹 K.J.巴斯蒂尔 于 2021-03-17 设计创作，主要内容包括：一种声音合成系统设置有扬声器和处理器,该扬声器用以响应于接收到合成声音(SS)信号而投射指示合成的马达声音的声音。该处理器被编程为：基于指示乘客舱内存在的声音的传感器信号来估计马达声音；用振幅和频率识别马达声音的优势马达谐波；确定马达声音的丰富度值；基于所述丰富度值与丰富度阈值的比较来确定所述马达声音是否未被丰富；响应于马达声音未被丰富,生成具有与优势马达谐波的频率不同的第一频率的至少一个附加马达谐波；并将SS信号提供给扬声器,其中SS信号指示该至少一个附加马达谐波。(A sound synthesis system is provided with a speaker to project sound indicative of synthesized motor sound in response to receiving a Synthesized Sound (SS) signal, and a processor. The processor is programmed to: estimating a motor sound based on a sensor signal indicative of sound present within the passenger compartment; identifying a dominant motor harmonic of the motor sound with amplitude and frequency; determining a richness value of the motor sound; determining whether the motor sound is not enriched based on a comparison of the richness value to a richness threshold; in response to the motor sound not being enriched, generating at least one additional motor harmonic having a first frequency different from the frequency of the dominant motor harmonic; and providing an SS signal to the speaker, wherein the SS signal is indicative of the at least one additional motor harmonic.)

1. A sound synthesis system, comprising:

a speaker to project sound indicative of the synthesized motor sound within a passenger compartment of the vehicle in response to receiving the Synthesized Sound (SS) signal; and

a processor programmed to:

estimating a motor sound based on a sensor signal indicative of sound present within the passenger compartment;

identifying a dominant motor harmonic of the motor sound with an amplitude and a frequency;

determining a richness value of the motor sound;

determining whether the motor sound is not enriched based on a comparison of the richness value to a richness threshold;

in response to the motor sound not being enriched, generating at least one additional motor harmonic having a first frequency different from the frequency of the dominant motor harmonic; and

providing the SS signal to the speaker, wherein the SS signal is indicative of the at least one additional motor harmonic.

2. The sound synthesis system of claim 1, wherein the processor is further programmed to generate a first additional motor harmonic having the first frequency and a second additional motor harmonic having a second frequency in response to the motor sound being not enriched, and wherein the first frequency is one octave less than the frequency of the dominant motor harmonic and the second frequency is at least two octaves less than the frequency of the dominant motor harmonic.

3. The sound synthesis system of claim 1, wherein the processor is further programmed to generate a first additional motor harmonic having the first frequency and a second additional motor harmonic having a second frequency in response to the motor sound being not enriched, and wherein the first frequency is one octave less than the frequency of the dominant motor harmonic and the second frequency is at least one octave less than the frequency of the dominant motor harmonic, wherein the motor sound present in the passenger compartment and the synthesized motor sound collectively provide a musical chord.

4. The sound synthesis system of claim 3, wherein the processor is further programmed to estimate the motor sound by filtering at least one of an audio signal and a synthesized engine signal from the sensor signal.

5. The sound synthesis system of claim 1, wherein the richness value comprises an absolute richness value of the motor sound, and wherein the processor is further programmed to:

determining an absolute sharpness value of the motor sound;

determining the absolute richness value of the motor sound based on the absolute sharpness value;

determining whether the motor sound is not enriched based on a comparison of the absolute richness value to the richness threshold; and

providing the SS signal to the speaker in response to the absolute richness value not exceeding the richness threshold.

6. The sound synthesis system of claim 1, wherein the richness value comprises an absolute richness value of the motor sound, and wherein the processor is further programmed to:

determining an absolute inverse roughness value of the motor sound;

determining the absolute richness value of the motor sound based on the absolute inverse roughness value;

determining whether the motor sound is not enriched based on a comparison of the absolute richness value to the richness threshold; and

providing the SS signal to the speaker in response to the absolute richness value not exceeding the richness threshold.

7. The sound synthesis system of claim 1, wherein the richness value comprises an absolute richness value of the motor sound, and wherein the processor is further programmed to:

determining an absolute loudness value of the motor sound;

determining an absolute pitch value of the motor sound;

determining the absolute richness value of the motor sound based on the absolute loudness value and the absolute pitch value;

determining whether the motor sound is not enriched based on a comparison of the absolute richness value to the richness threshold; and

providing the SS signal to the speaker in response to the absolute richness value not exceeding the richness threshold.

8. The sound synthesis system of claim 1, wherein the richness value comprises an absolute richness value of the motor sound, and wherein the processor is further programmed to:

determining at least one of an absolute sharpness value, an absolute roughness value, an absolute loudness value, and an absolute pitch value of the motor sound;

determining an absolute richness value of the motor sound based on at least one absolute value of the motor sound;

determining whether the motor sound is not enriched based on a comparison of the absolute richness value to the richness threshold; and

providing the SS signal to the speaker in response to the absolute richness value not exceeding the richness threshold.

9. A vehicle sound synthesis system, comprising:

a speaker to project sound indicative of the synthesized motor sound within a passenger compartment of the vehicle in response to receiving the Synthesized Sound (SS) signal;

a microphone to provide a microphone signal indicative of sound present within the passenger compartment; and

a controller configured to:

estimating a motor sound based on the microphone signal;

identifying a dominant motor harmonic of the motor sound with an amplitude and a frequency;

determining a richness value of the motor sound;

determining whether the motor sound is not enriched based on a comparison of the richness value of the motor sound to a richness threshold;

in response to the motor sound not being enriched, generating at least one additional motor harmonic having a first frequency that is less than the dominant motor harmonic; and

providing the SS signal to the speaker, wherein the SS signal is indicative of the at least one additional motor harmonic.

10. The vehicle sound synthesis system of claim 9, where the controller is further configured to:

in response to the motor sound not being enriched, generating a first additional motor harmonic having the first frequency and a second additional motor harmonic having a second frequency; and is

Wherein the first frequency is at least one octave less than the frequency of the dominant motor harmonic and the second frequency is at least one octave less than the frequency of the dominant motor harmonic.

11. The vehicle sound synthesis system of claim 10, wherein the controller is further configured to generate the first additional motor harmonic and the second additional motor harmonic such that the motor sound present in the passenger compartment and the synthesized motor sound collectively provide a musical chord.

12. The vehicle sound synthesis system of claim 9, wherein the richness value comprises a relative richness value of the motor sound, and wherein the controller is further configured to:

determining a relative sharpness value of the motor sound;

determining the relative richness value of the motor sound based on the relative sharpness value;

comparing the relative richness value to the richness threshold to determine whether the motor sound is not richened; and

providing the SS signal to the speaker in response to the relative richness value not exceeding the richness threshold.

13. The vehicle sound synthesis system of claim 9, wherein the richness value comprises a relative richness value of the motor sound, and wherein the controller is further configured to:

determining a relative inverse roughness value of the motor sound;

determining the relative richness value of the motor sound based on the relative inverse roughness value;

comparing the relative richness value to the richness threshold to determine whether the motor sound is not richened; and

providing the SS signal to the speaker in response to the relative richness value not exceeding the richness threshold.

14. The vehicle sound synthesis system of claim 9, wherein the richness value comprises a relative richness value of the motor sound, and wherein the controller is further configured to:

determining a relative loudness value of the motor sound;

determining a relative pitch value of the motor sound;

determining the relative richness value of the motor sound based on the relative loudness value and the relative pitch value;

comparing the relative richness value to the richness threshold to determine whether the motor sound is not richened; and

providing the SS signal to the speaker in response to the relative richness value not exceeding the richness threshold.

15. The vehicle sound synthesis system of claim 9, wherein the richness value comprises a relative richness value of the motor sound, and wherein the controller is further configured to:

determining at least one of a relative sharpness value, a relative roughness value, a relative loudness value, and a relative pitch value of the motor sound;

determining a relative richness value of the motor sound based on at least one relative value of the motor sound;

comparing the relative richness value to the richness threshold to determine whether the motor sound is not richened; and

providing the SS signal to the speaker in response to the relative richness value not exceeding the richness threshold.

16. A computer program product, embodied in a non-transitory computer readable medium, the computer program product programmed to synthesize motor sound, the computer program product comprising instructions for:

receiving a sensor signal indicative of sound present within a passenger compartment of the vehicle;

estimating a motor sound based on the sensor signal;

identifying a dominant motor harmonic of the motor sound with an amplitude and a frequency;

in response to the motor sound not being enriched, generating at least one additional motor harmonic having a first frequency that is less than the dominant motor harmonic; and

providing a Synthesized Sound (SS) signal to a speaker for projection as sound within the vehicle passenger compartment, wherein the SS signal is indicative of the at least one additional motor harmonic.

17. The computer program product of claim 16, further comprising instructions for:

generating a first additional motor harmonic having the first frequency and a second additional motor harmonic having a second frequency in response to the motor sound not being enriched, wherein the first frequency is at least one octave less than the frequency of the dominant motor harmonic and the second frequency is at least two octaves less than the frequency of the dominant motor harmonic.

18. The computer program product of claim 17, further comprising instructions for:

generating the first additional motor harmonic and the second additional motor harmonic such that the motor sounds present in the passenger compartment and the synthesized motor sounds collectively provide a musical chord.

19. The computer program product of claim 16, further comprising instructions for:

determining at least one of an absolute value and a relative sharpness value of the motor sound;

determining at least one of an absolute richness value and a relative richness value of the motor sound based on the at least one of the absolute value and the relative sharpness value;

comparing the at least one of the absolute richness value and the relative richness value to a richness threshold to determine whether the motor sound is not richened; and

providing the SS signal to the speaker in response to the at least one of the absolute richness value and the relative richness value not exceeding the richness threshold.

20. The computer program product of claim 16, further comprising instructions for:

determining at least one of a relative or absolute sharpness value, a relative or absolute roughness value, a relative or absolute loudness value, and a relative or absolute pitch value of the motor sound;

determining a relative or absolute richness value of the motor sound based on at least one relative or absolute value of the motor sound;

comparing the relative or absolute richness value to a richness threshold to determine whether the motor sound is not richened; and

providing the SS signal to the speaker in response to the relative or absolute richness value not exceeding the richness threshold.

Technical Field

One or more embodiments relate to vehicle systems and methods for masking sounds generated by an electric traction motor of an electrified vehicle.

Background

The noise generated by the vehicle components is typically audible to both the driver and any passengers in the passenger compartment. For example, the driver may hear noise generated by the engine of the powertrain and the exhaust system of the vehicle. The natural sound of electrified vehicles, such as Hybrid Electric Vehicles (HEVs) and Electric Vehicles (EVs), is different from the natural sound of vehicles having an internal combustion engine. For example, an HEV may operate as an EV with an Internal Combustion Engine (ICE) turned off, during which the HEV does not generate typical engine noise. While drivers may be accustomed to hearing cues from the internal combustion engine regarding vehicle operation (e.g., low frequency rumble and sound levels and tones that increase as vehicle or engine speed increases), electric traction motors have a relatively quiet, relatively high frequency squeal in most conditions. However, the driver may be able to perceive other noises of the electrified vehicle that are not perceptible during normal operation of the internal combustion engine-driven vehicle. For example, sounds emanating from tires, suspensions, general vehicle noise, vibration, harshness (NVH) of the system rather than the drive train, and high frequency electric motor squeal may be evident under typical driving conditions.

Disclosure of Invention

In one embodiment, a sound synthesis system is provided with a speaker to project sound indicative of synthesized motor sound within a passenger compartment of a vehicle in response to receiving a Synthesized Sound (SS) signal, and a processor. The processor is programmed to: estimating a motor sound based on a sensor signal indicative of sound present within the passenger compartment; identifying a dominant motor harmonic of the motor sound with amplitude and frequency; determining a richness value of the motor sound; determining whether the motor sound is not enriched based on a comparison of the richness value to a richness threshold; in response to the motor sound not being enriched, generating at least one additional motor harmonic having a first frequency different from the frequency of the dominant motor harmonic; and providing an SS signal to the speaker, wherein the SS signal is indicative of the at least one additional motor harmonic.

In another embodiment, a vehicle sound synthesis system is provided with: a speaker to project sound indicative of the synthesized motor sound within a passenger compartment of the vehicle in response to receiving the Synthesized Sound (SS) signal; a microphone to provide a microphone signal indicative of sound present within the passenger compartment; and a controller configured to: estimating a motor sound based on the microphone signal; identifying a dominant motor harmonic of the motor sound with an amplitude and a frequency; determining a richness value of the motor sound; determining whether the motor sound is not enriched based on a comparison of the richness value of the motor sound to a richness threshold; in response to the motor sound not being enriched, generating at least one additional motor harmonic having a first frequency that is less than the dominant motor harmonic; and providing the SS signal to the speaker, wherein the SS signal is indicative of the at least one additional motor harmonic.

In another embodiment, a computer program product, embodied in a non-transitory computer readable medium, is provided that is programmed to synthesize motor sound. The computer program product includes instructions for: receiving a sensor signal indicative of sound present within a passenger compartment of the vehicle; estimating a motor sound based on the sensor signal; identifying a dominant motor harmonic of the motor sound with an amplitude and a frequency; in response to the motor sound not being enriched, generating at least one additional motor harmonic having a first frequency that is less than the dominant motor harmonic; and providing a Synthesized Sound (SS) signal to a speaker for projection as sound within the vehicle passenger compartment, wherein the SS signal is indicative of the at least one additional motor harmonic.

Drawings

Embodiments of the present disclosure are particularly pointed out in the appended claims. However, other features of the various embodiments will become more apparent and will be best understood by referring to the following detailed description in conjunction with the accompanying drawings, in which:

fig. 1 is a schematic diagram of a vehicle system for generating simulated vehicle sounds, shown as an electrified vehicle, according to one or more embodiments.

FIG. 2 is a schematic block diagram of the vehicle system of FIG. 1.

Fig. 3 is a flow diagram illustrating a method for generating a synthesized motor sound in accordance with one or more embodiments.

Fig. 4A is a musical scale showing a joint vocal interval.

Fig. 4B is a musical scale showing discordance with a voice interval.

FIG. 5 is a table listing frequency ratios of the equal temperaments.

Fig. 6A is a graph illustrating the natural sound of the motor of the electrified vehicle of fig. 1.

Fig. 6B is a graph illustrating natural sounds of a motor of the electrified vehicle of fig. 6A and synthesized motor sounds generated by the vehicle system of fig. 1, in accordance with one or more embodiments.

Fig. 6C is a graph illustrating the natural and synthesized motor sounds of fig. 6A and 6B and additional synthesized motor sounds generated by the vehicle system of fig. 1.

Fig. 7A-7C are graphs illustrating the sharpness of the motor sound shown in fig. 6A-6C as determined by the vehicle system of fig. 1.

8A-8C are graphs illustrating the roughness of the motor sound shown in FIGS. 6A-6C as determined by the vehicle system of FIG. 1.

FIG. 9 is a graph of the richness of the motor sounds shown in FIGS. 6A-6C as determined by the vehicle system of FIG. 1.

Detailed Description

As required, detailed embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary and may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present disclosure.

Referring to fig. 1, a vehicle system for generating simulated vehicle sounds is shown in accordance with one or more embodiments and is generally represented by numeral 110. The vehicle system 110 is depicted within a vehicle 112. The vehicle 112 includes a powertrain 114 having a transmission 116, an Internal Combustion Engine (ICE)118, and an electric traction motor 120. The vehicle system 110 includes a controller 122, a plurality of speakers 124(124A, 124B), and at least one microphone 126. In an embodiment, the vehicle system 110 includes only one speaker 124A.

The illustrated embodiment depicts a vehicle system 110 having a first speaker 124A mounted forward in the passenger compartment 128, a second woofer 124B mounted to the door of the vehicle, and a microphone 126 mounted to the headliner in the passenger compartment 128. Traction motors for electrified vehicles, such as motor 120, typically generate high frequency motor noise or squeal at 1kHz or above. In addition, such motors typically produce a high frequency noise order that, due to the sparsity of the harmonics, and thus lack of richness and fullness, can result in an unpleasant, and un-richened motor sound. The vehicle system 110 analyzes the high frequency noise or basic squeal of the motor 120 present in the passenger compartment 128; determining whether noise is not enriched; and if so, generating additional low frequency harmonics to add to the motor sound to collectively modify and increase the richness of the motor sound.

The controller 122 communicates with other vehicle systems and controllers via one or more vehicle networks 130 through wired or wireless communication. The vehicle network 130 may include a plurality of channels for communication. One possible channel of a vehicle network is a serial bus, such as a Controller Area Network (CAN). Another possible channel of a vehicle network includes an ethernet network defined by the Institute of Electrical and Electronics Engineers (IEEE)802 series of standards. Additional channels of the vehicle network may include discrete connections between modules and may include power signals. Different signals may be transmitted on different channels of the vehicle network. For example, the video signal may be transmitted on a high speed channel (e.g., ethernet) while the pilot signal may be transmitted on a CAN or discrete signal. The vehicle network may include any hardware and software components that facilitate the communication of signals and data between the modules and the controller.

Although the controller 122 is shown as a single controller, it may contain multiple controllers, or it may be embodied as software code within one or more other controllers. The controller 122 generally includes any number of microprocessors, ASICs, ICs, memory (e.g., FLASH, ROM, RAM, EPROM, and/or EEPROM), and software code to cooperate with one another to perform a series of operations. Such hardware and/or software may be grouped together in modules to perform certain functions. Any one or more of the controllers or devices described herein comprise computer-executable instructions that may be compiled or interpreted from computer programs created using a variety of programming languages and/or techniques. Generally, a processor (such as a microprocessor), for example, receives instructions from a memory, a computer-readable medium, etc., and executes the instructions. The processing unit includes a non-transitory computer-readable storage medium capable of executing instructions of a software program. The computer readable storage medium may be, but is not limited to, an electronic memory device, a magnetic memory device, an optical memory device, an electromagnetic memory device, a semiconductor memory device, or any suitable combination thereof. According to one or more embodiments, the controller 122 also includes predetermined data or a "look-up table" stored in memory.

Fig. 2 is a block diagram 200 illustrating aspects of the vehicle system 110 according to one or more embodiments. The vehicle system 110 generates a synthesized motor sound based on a plurality of signals indicative of the current vehicle condition, and predetermined information. The microphone 126 measures sound present in its vicinity and provides a corresponding signal (MIC). According to the embodiment shown in fig. 1, the microphone 126 is located in the passenger compartment 128. However, other embodiments of the vehicle system 110 may alternatively include the microphone 126 located in the rear cargo compartment 132, i.e., the luggage compartment, or the front cargo compartment 134, i.e., the "front cargo compartment," or in another location of the vehicle 112. The sound present on the MIC signal will vary depending on the position of the microphone 126. For example, a microphone 126 located in the passenger compartment 128 will detect motor sounds and additional sounds, such as music from the vehicle audio system, synthesized sounds, and speech from the passenger; and a microphone located in the trunk or front trunk may not be able to detect such additional sound. The vehicle system 110 is designed to analyze the howling of the high frequency motor, but other sounds may be present in the MIC signal, and thus, in one or more embodiments, the vehicle system 110 eliminates or reduces the amplitude of such signals present in the MIC signal. In other embodiments, the vehicle system estimates motor sound from MIC signals and/or signals provided by other sensors (e.g., accelerometers, dynamometers, geophones, linear variable differential transformers, strain gauges, and load cells).

In one embodiment, the vehicle system 110 includes an AUDIO system module 202 that provides AUDIO signals to the speaker 124 to emit corresponding sounds, such as music. The AUDIO system module 202 also provides an AUDIO signal along a stored secondary path 204 that the vehicle system 110 uses to cancel or reduce the amplitude of the AUDIO component from the MIC signal, as shown by a summing block 206. In an embodiment, an adaptive system, such as a Least Mean Square (LMS) system, may also be used to provide an estimate of the secondary path 204 instead of using a stored secondary path.

The vehicle system 110 includes a synthetic sound generator module 208, the synthetic sound generator module 208 for generating a Synthetic Sound (SS) to mask or eliminate natural sounds, such as motor sounds and/or engine sounds. The SS includes a Synthesized Motor Sound (SMS) to mask or enhance a natural motor sound. In one or more embodiments, the SS further includes a Synthetic Engine Sound (SES) to mask or enhance the natural engine sound. The synthesized sound generator module 208 generates the SS using a sine wave sound generator, an oscillator, a modulated wav player, or broadband noise. In one or more embodiments, the vehicle system 110 eliminates or reduces the amplitude of the (SES) component of the overall SS signal by providing a Synthesized Engine Sound (SES) signal along the feed-forward stored secondary path 210, as shown by summing block 212.

The vehicle system 110 includes a signal analysis module 214, the signal analysis module 214 analyzing a MIC signal indicative of MOTOR sound (MOTOR). As described above, in some embodiments, the vehicle system 110 filters the MIC signal to remove the AUDIO component and SES component from the signal. The signal analysis module 214 analyzes the MOTOR signal with reference to one or more other vehicle signals 216 received from other systems, such as MOTOR speed, engine speed, vehicle speed, pedal position, drive axle speed, vehicle acceleration, etc., to determine whether the MOTOR is an unflavored sound. If the MOTOR is not enriched, the signal analysis module 214 instructs the synthesized sound generator module 208 to generate additional high frequency Synthesized Sounds (SS)_HF) To mask or enrich the un-enriched motor sound.

Referring to fig. 3, a method for masking high frequency motor noise is shown in accordance with one or more embodiments and is generally referred to by the numeral 300. According to one or more embodiments, the method is implemented using software code contained in the controller 122. Although the method is described using a flowchart that shows steps in a number of sequential steps, in one or more other embodiments, one or more steps may be omitted and/or performed in another manner.

At step 302, the vehicle system 110 receives input signals, such as MIC signals, from within the vehicle system 110 itself, as well as signals provided by other vehicle systems. At step 304, the vehicle system 110 estimates the motor sound. The vehicle system 110 optionally eliminates or reduces the amplitude of non-MOTOR components (e.g., music and synthesized engine sounds) present on the MIC signal to filter out remaining MOTOR Sounds (MOTORs), as described above with reference to fig. 2.

At step 306, 308, the vehicle system 110 compares the motor sound and the statistical data derived from the motor sound to predetermined data to determine if it is not enriched. Motor richness (Er) refers to a complex feeling that is affected by various psychoacoustic components. In one or more embodiments, the vehicle system 110 is based on the inverse ratio of roughness (R)^-1) Sharpness (S), pitch (T) and loudness (N) the absolute richness (Er) of the motor sound is determined according to equation 1:

absolute richness values refer to the actual size of the calculated richness value, regardless of its relationship to other richness values.

In one or more embodiments, the vehicle system 110 may also be based on the inverse ratio of roughness (R)^-1) Sharpness (S), pitch (T) and loudness (N) the relative richness value (Er/Er) of the motor sound is determined according to equation 2₀)：

The vehicle system 110 compares the absolute value of each component to a nominal value to determine its relative value. For example, the vehicle system 110 determines a nominal abundance (Er)₀) Then the absolute abundance (Er) is compared to the nominal abundance (Er)₀) Comparison to determine relative abundance (Er/Er)₀). The nominal value is based on the passenger compartment acoustics before the vehicle system 110 generates the additional sound. In other embodiments, the vehicle system 110 is based on a subset of these sound quality components, i.e., absolute or relative inverse roughness (R)^-1) Sharpness (S), pitch (T) and/or loudness (N).

At step 308, the vehicle system 110 compares the absolute richness value (or relative richness value) to a predetermined richness threshold to determine whether the motor sound is not richened.

In one embodiment, at step 306-308, the vehicle system 110 determines whether the motor sound is not rich based solely on the sharpness (S). Sharpness is a measure of the high frequency content of a sound, the greater the proportion of high frequencies, the "sharper" the sound. Sharpness is the factor that most affects the richness of the motor. The vehicle system 110 determines the sharpness of the MOTOR sound (MOTOR) by analyzing the spectral content and center frequency of the sound within a narrow frequency band.

The vehicle system 110 uses the Acum scale to determine the sharpness (S) of the motorr signal in the passenger compartment 128. 1Acum is narrow-band noise, which is a critical bandwidth with a 60dB level at the 1k Hz center frequency. The critical bands are determined in a Bark scale, which is a frequency scale where equal distances correspond to perceptually equal distances. The vehicle system 110 calculates the sharpness (S) of the motorr signal based on the specific loudness N', as shown in equation 3:

in other embodiments, the vehicle system 110 may use other psychoacoustically similar, but numerically different sharpness formulas.

Specific loudness (N') is based on the assumption that the relative change in loudness is proportional to the relative change in intensity. The vehicle system 110 measures the loudness (N) of the motor sound using the microphone 126. Loudness corresponds to the subjective sound intensity of the stimulus and is measured in sones. One song equals the 40dB level of the 1-kHz tone. The vehicle system is then excited (E) based on the excitation, the test tone excitation (E)_TQ) And intensity of contrast in G index (E)₀) Corresponding excitation (SONE)_G) The specific loudness (N') of the motor sound is calculated as shown in equation 4:

in other embodiments, the vehicle system 110 may use other psychoacoustically similar but numerically different loudness formulas.

The vehicle system 110 determines the absolute sound richness (Er) of the motor sound according to equation 5 based on the absolute sharpness (S):

Er＝e^-1.08*S (5)

in additional embodiments, the vehicle system 110 is based on relative sharpness (S/S)₀) Relative sound richness (E) is determined according to equation 6_r/Er₀)：

At step 308, the vehicle system 110 compares the absolute richness value or the relative richness value to a predetermined richness threshold to determine whether the motor sound is not richened. Generally, this sharpness-based richness determination method is more effective for high frequency sounds than for low frequency sounds, and thus, is more suitable for EV vehicles or HEVs operating in EV mode due to high frequency traction motor noise than conventional vehicles with ICEs that produce relatively low frequency engine sounds.

FIG. 7A shows an embodiment where the vehicle system 110 compares the absolute richness value based on the absolute sharpness calculated in equation 5 to an absolute threshold of 2.5S/Accum depicted by dashed line 710. FIG. 7A shows a baseline state sharpness curve 702 at high rotational speeds exceeding a threshold 710 after about 3.0 seconds.

In another embodiment, at step 306-308, the vehicle system 110 is based only on inverse roughness (R)^-1) To determine if the motor sound is not enriched. Roughness results from relatively rapid changes in amplitude produced by modulation frequencies below 300 Hz. The vehicle system 110 determines a nominal roughness value based on the Asper scale. The relative roughness is determined by analyzing the modulation degree and modulation frequency of tones below 300 Hz. The roughness of the 1asper was determined to be a 1kHz tone modulated at 60dB at 70 Hz. The vehicle system 110 calculates the roughness (R) of the MOTOR signal based on the masking depth (L), as shown in equation 7:

in other embodiments, the vehicle system 110 may use other psychoacoustically similar but numerically different roughness recipes.

The masking depth (L) is the difference between the maximum and minimum values in the temporal masking pattern. Vehicle system 110 is based on inverse roughness absolute (R)^-1) Absolute sound richness (E) is determined according to equation 8_r)：

In additional embodiments, the vehicle system 110 is based on relative inverse roughness (R)^-1/R₀ ^-1) Determining the relative richness of motor sound (Er/Er) according to equation 9₀)：

At step 308, the vehicle system 110 compares the absolute richness value or the relative richness value to a predetermined richness threshold to determine whether the motor sound is not richened. Such an inverse roughness-based richness determination method is generally more effective for low-frequency sounds than for high-frequency sounds, and therefore, is more suitable for a conventional vehicle having an ICE that generates low-frequency sounds than an EV vehicle that generates high-frequency motor squeal or an HEV that operates in an EV mode.

In another embodiment, at step 306-308, the vehicle system 110 determines whether the motor sound is not enriched based on the loudness and pitch of the motor sound. As described above, loudness corresponds to sound intensity, and loudness affects both roughness and sharpness. The vehicle system 110 measures loudness in sones using the microphone 126. The vehicle system 110 includes a loudness threshold, e.g., 676 sone, which corresponds to a threshold of approximately 140dB of auditory pain. Pitch refers to the timbre of sound and is also included in the motor richness equation, but with minimal impact. Pitch is neither dependent on critical band rate nor on loudness. However, the relative pitch depends on the bandwidth expressed in critical band rate expansion, such that it decreases as the critical band rate expansion increases. The pitch is subjectively determined, and thus the vehicle system 110 includes predetermined data indicative of the pitch of the motor sound. The vehicle system 110 determines the absolute sound richness (E) according to equation 10 based on the absolute pitch (R) and the absolute loudness (N)_r)：

In additional embodiments, the vehicle system 10 is based on relative tone (T/T)₀) And relative loudness (N/N)₀) Determining the relative richness of motor sound (Er/Er) according to equation 11₀)：

At step 308, the vehicle system 110 compares the relative richness to a predetermined richness threshold to determine whether the motor sound is not enriched. This method of determining richness based on loudness and pitch is generally effective over a wide frequency range, and therefore, it is applicable to both electrified vehicles (e.g., HEVs and EVs) as well as conventional vehicles with ICEs.

In one embodiment, the vehicle system 110 employs the equal law system approach and adds an additional "overtone" that is one, two, or more than two octaves lower than the measured motor sound at step 310. In music and electronics, octaves are logarithmic units of ratios between frequencies, one octave corresponding to twice or half of a frequency. Thus, for a MOTOR signal of 800Hz, the sub-harmonic that is 1 octave lower will be at 400Hz, and the sub-harmonic that is 2 octaves lower will be at 200 Hz. The presence of three tones spaced apart in octaves may still be a harmonically sparse acoustic signature, and the vehicle system 110 may generate additional frequencies to achieve a synergistic and rich acoustic signature.

In another embodiment, at step 302-. According to one or more embodiments, the signal analysis module 214 (fig. 2) includes a peak detector. The peak detector detects the amplitude of each motor sound peak. In various embodiments, the analysis may be done using the microphone signal MIC or a signal for another type of transducer. Since the signature sounds of electric motors are single-frequency (sine wave) sounds, their natural sounds are not enriched. The vehicle system 110 may generate a synthesized voice tone at a frequency ratio of 0.5, which is one octave lower in frequency to reduce sparsity and increase richness. In an embodiment, the tones are generated at a frequency ratio corresponding to a known stable or harmonious interval, e.g., minor three, major three, pure four, pure five, minor six, major six, or octave, and thus the vehicle system 110 determines that the motor sound is pleasant and rich. However, in an embodiment, if the average law ratio corresponds to a known unstable or uncoordinated interval, e.g., a lesser than two degrees, a greater than two degrees, a third harmonic, a lesser than seven degrees, or a greater than seven degrees, the vehicle system 110 determines that the motor sound is unpleasant and not enriched.

After the vehicle system 110 determines at step 308 that the MOTOR sound is not enriched, the vehicle system 110 proceeds to step 310 and generates additional sub-harmonics of the MOTOR signal to mask the MOTOR sound with additional synthesized sound that is not enriched. For example, referring to fig. 7A-7C, after the absolute richness curve 702 exceeds the threshold 710, the vehicle system 110 determines that the motor sound is not rich and generates additional sub-harmonics, as shown by the lower richness curve 704 in fig. 7B. Then, after the absolute richness curve 704 exceeds the threshold 710, the vehicle system 110 determines that the motor sound is still not rich and generates additional sub-harmonics, as shown by the lower richness curve 706 in FIG. 7C.

The vehicle system 110 utilizes the method 300 during steady state driving and also during acceleration and deceleration. In one or more embodiments, the vehicle system 110 uses a sound localization algorithm, such as the sound localization algorithm described in US 10,065,561, to localize the generated sound in the direction of the motor squeal, thereby increasing the masking effect.

Vehicle occupants are accustomed to the harmonic-rich sound experience of conventional ICE-powered vehicles. For example, a 4-cylinder ICE radiates essentially 2 steps, except for the upper 4, 6, 8, and 16 steps. Under heavy engine loads, 2.5 steps and 4.5 steps with large amplitude are also generated. Thus, vehicle occupants are accustomed to a harmonically rich engine sound signature, rather than a single tone of EV motor squeal. For an internal combustion engine, the order is a proportional relationship between engine RPM and the audible frequency produced. The simulation for an EV is that the order is a proportional relationship between electric traction motor RPM and audible frequency. The spacing between the dominant and lower orders creates a spacing or interval defined by the ratio and corresponds to the spacing between notes.

Musical intervals refer to the spacing between frequencies between tones of a harmonic series. The pitch of the intervals may be divided into whole and half tones to produce a steady or harmonious tone. Fig. 4A is a scale of a stable or harmonious interval between tones, including minor third, major third, pure fourth, pure fifth, minor sixth, major sixth, and octave. Fig. 4B is a scale of unstable or uncoordinated intervals between tones, including minor second, major second, third, minor seventh and major seventh. The dominant highest frequency tone detected by the microphone represents the lower dominant or leading tone. From the lead, the cove interval may be added at a lower frequency based on the equal temperament ratio.

The only pure musical interval is the octave. An octave may be divided into twelve equally spaced notes or semitones on a chromatic scale, and all the semitones sound the same spacing in frequency or pitch. If two notes are added within the same harmonic series of the initially detected highest order, the additional tones can complement and enhance each other, presenting a harmonious tone to the human ear. The actual frequencies of the notes are not important, but how they are compared to each other (i.e., harmonic spacing or pitch ratio) is important. The equal law method is based on a twelve-quadratic root that divides the octave into twelve equal tones, as listed in fig. 5.

Just as different combinations of notes can be combined to create an ear-pleasing musical "chord," the vehicle system 110 combines the orders to create a "chord" that achieves harmonic balancing during acceleration, deceleration, or steady state driving to create a sound signature that masks or balances unwanted or unpleasant motor noise. In music theory, a major chord is a chord having a major note, major third and pure fifth. For example, if the vehicle has a 4 th order of dominance, the vehicle system 110 may add a large third degree note by multiplying the measured frequency of the fourth order sound by a coefficient of 1.2599, as indicated by numeral 502; and the vehicle system 110 may add pure fifth degree notes by multiplying the fourth order frequency by a coefficient of 1.4983, as indicated by numeral 504, such as into 5.0625 or 6 orders, respectively, to create a C chord. For EV sound creation, the dominant order is much more frequent than the typical engine order. Common engine steps include frequencies below 300Hz, while electric motors typically include frequencies above-1000 Hz. In an embodiment, only the low frequency order is synthesized. In an embodiment, based on the frequency ratios detailed in fig. 5, lower synthesis orders are synthesized to create a synergistic interval, such as the one listed in fig. 4A.

It is noted that the frequency ratios specified above are the exact notes of the equal temperament tuning interval. Other tuned intervals, such as rational tuned intervals, also exist in music. The difference between these tuned intervals is as much as nine or ten cents or more (with the cents being 1/100 for semitones), indicating that some margin around the frequencies of these exact frequency ratios still results in a harmonious, harmonious interval. Thus, useful embodiments are not limited to these exact frequency ratios.

Fig. 6-9 illustrate examples of the impact of methods for masking high frequency motor noise or enriching an un-enriched motor sound. Fig. 6A is a graph 600 including a plurality of curves illustrating natural harmonics of the motor 120 estimated by the vehicle system 110 at step 304 during a vehicle acceleration event. The motor sound includes a dominant 96-step 602, corresponding to 96 times the motor shaft speed, and a low fundamental step: 24 th, 16 th and 8 th, represented by numerals 604, 606 and 608, respectively. As shown in fig. 6A, the dominant 96 th order 602 is much higher in frequency than the lower fundamental order.

7A-7C and 9 illustrate examples of the vehicle system 110 determining richness based on sharpness. Fig. 7A is a graph 700 including a curve 702 illustrating the natural sharpness of a motor sound over time as determined by the vehicle system 110. As shown in fig. 7A, the sharpness increases from about 0.25Acum to about 3.5Acum in about 5.5 seconds.

FIG. 9 is a graph 900 including a curve 902 illustrating the relative richness of the motor sound determined by the vehicle system 110. Graph 900 includes relative abundance (Er/Er) on the y-axis₀) And relative sharpness (S/S) in the x-axis₀) For sharpness-based richness determination. A curve 902 represents the relative richness calculated using equation 6, and a dashed line 904 represents the predetermined richness threshold. The representative time T on the graph 700₀Time T of₀Is the vehicle system 110 determines the sharpness (i.e., S)₀) The first point of (a). T is₀The relative sharpness is equal to 1, since the absolute sharpness (S) is equal to the nominal sharpness (S)₀). The vehicle system 110 determines at T₀Relative abundance of (P/P)₀) Less than threshold 904 and then synthesizes additional motor sounds.

Referring to fig. 5 and 6B, the vehicle system 110 generates additional Synthesized Motor Sounds (SMS) or harmonics with frequencies lower than the natural motor sounds shown in the graph 600' (fig. 6B). The vehicle system 110 generates a large second order 612 (fig. 6B) with a lower frequency by dividing the dominant order 602 by the coefficient of 1.1225, as indicated by numeral 506 in fig. 5. The vehicle system 110 generates a 4.5 order 614 by dividing the dominant order 602 by the coefficients of 1.4983, as indicated by numeral 504.

Referring to fig. 7B and 9, the vehicle system 110 compares the natural motor sound combined synthesized motor sound with predetermined data to determine whether it has not yet been enriched. Fig. 7B is another graph 700' that includes a curve 704 that illustrates the sharpness of the motor sound synthesized by the motor sound combination determined by the vehicle system 110. As shown in FIG. 7B, sharpness 704 increases from about 0.0.3Acum to about 2.9Acum in about 5.5 seconds, which is less than the maximum sharpness of curve 702 in FIG. 7A. Referring to fig. 9, the vehicle system 110 determines the relative richness of the motor sound shown in graph 600 '(fig. 6B) and graph 700' (fig. 7B), which is represented by time T on richness curve 902₁And (4) quoted. Albeit from time T₀To time T₁The richness of (b) is improved, but the vehicle system 110 determines that the relative richness is still less than the threshold 904, and thus, has not yet been enriched. The vehicle system 110 then synthesizes the additional motor sound.

Referring to fig. 5 and 6C, the vehicle system 110 generates additional Synthesized Motor Sounds (SMS) or harmonics with frequencies lower than the natural motor sounds shown in the graph 600 "(fig. 6C). The vehicle system 110 generates a large third order 622 by dividing the dominant order 602 by coefficients of 1.2599, as indicated by numeral 502 in fig. 5. The vehicle system 110 also generates a pure 5 degree order 624 by dividing the dominant order 602 by the coefficients of 1.4983, as indicated by numeral 504.

Referring to fig. 7C and 9, the vehicle system 110 compares the natural motor sound combined synthesized motor sound with predetermined data to determine whether it has not yet been enriched. Fig. 7C is another graph 700 "that includes a curve 706 that illustrates the sharpness of the motor sound synthesized by the motor sound combination determined by the vehicle system 110. As shown in fig. 7C, the sharpness of curve 706 increases from about 0.0.3Acum to about 2.5Acum in about 5.5 seconds, which is less than the maximum sharpness of curve 704 in fig. 7B.

Referring to FIG. 9, the vehicle system 110 determines the relative richness of the motor sounds shown in FIGS. 6C and 8C, which is represented on the richness curve 902 by time T₂And (4) quoted. The vehicle system 110 determines that the relative richness is greater than the threshold 904, i.e., not richened (or richened), which results in a negative determination at step 308, and therefore, the vehicle system 110 does not generate additional motor sound harmonics, but instead returns to step 302.

In other embodiments, the vehicle system 110 determines richness based on inverse roughness. 8A-8C and 9 illustrate examples of the vehicle system 110 determining richness based on inverse roughness. Fig. 8A is a graph 800 including a curve 802 illustrating the natural roughness of the motor sound as determined by the vehicle system 110. As shown in graph 800 (FIG. 8A), the roughness increased from about 0.00Asper to about 0.10Asper in about 5.5 seconds.

FIG. 9 is a graph 900 of the relative richness of the motor sound determined by the vehicle system 110. Graph 900 includes relative abundance (Er/Er) on the y-axis₀) And now, for this embodiment, the x-axis of FIG. 9 corresponds to the relative inverse roughness (R)^-1/R₀ ^-1). The curve 902 now represents the relative richness calculated using equation 9, and the dashed line 904 represents the predetermined richness threshold. The representation time T on the graph 800₀Time T of₀Is that the vehicle system 110 determines the inverse roughness (i.e., R)₀ ^-1) The first point of (a). T is₀Relative inverse roughness of (A) is equal to 1 because of the absolute inverse roughness (R)^-1) Equal to the nominal inverse roughness (R)₀ ^-1). The vehicle system 110 determines at T₀Less than a threshold 904 and then synthesizing additional motor sounds.

Referring to fig. 5 and 6B, the vehicle system 110 generates additional motor harmonics that are lower in frequency than the natural motor sound. The vehicle system 110 generates a large second order 612 (fig. 6B) by dividing the dominant order 602 by the coefficients of 1.1225, as indicated by numeral 506 in fig. 5. The vehicle system 110 generates a 4.5 order 614 by dividing the dominant order 602 by the coefficients of 1.4983, as indicated by numeral 504.

Referring to fig. 8B and 9, the vehicle system 110 compares the motor sound synthesized by combining the natural motor sounds with predetermined data to determine whether it has not yet been enriched. Fig. 8B is another graph 800' that includes a curve 804 that illustrates the roughness of the natural motor sound combination synthesized motor sound determined by the vehicle system 110. As shown in FIG. 8B, roughness curve 804 increases from about 0.00Asper to about 0.29Asper, which is greater than the maximum roughness of curve 802 in FIG. 8A.

Referring to FIG. 9, the vehicle system 110 determines the relative richness of the motor sounds shown in FIGS. 6B and 8B, which is represented on the richness curve 902 by time T₁And (4) quoted. Although from T₀To T₁The richness of (b) is improved, but the vehicle system 110 determines that the relative richness is still less than the threshold 904, and thus, has not yet been enriched. The vehicle system 110 then synthesizes the additional motor sound.

Referring to fig. 5 and 6C, the vehicle system 110 generates additional motor harmonics that are lower in frequency than the natural motor sound. The vehicle system 110 generates a large third order 622 by dividing the dominant order 602 by coefficients of 1.2599, as indicated by numeral 502. The vehicle system 110 generates a pure fifth order 624 by dividing the dominant order 602 by coefficients of 1.4983, as indicated by numeral 512.

Referring to fig. 8C and 9, the vehicle system 110 compares the natural motor sound combined synthesized motor sound with predetermined data to determine whether it is still not enriched (or enriched). Fig. 8C is another graph 800 "that includes a curve 806, the curve 806 illustrating the roughness of the natural motor sound combined synthesized by the vehicle system 110. As shown in FIG. 8C, roughness 806 increases from about 0.00Asper to about 0.28Asper in about 5.5 seconds, which is similar to the maximum roughness of curve 802 in FIG. 8A.

Referring to FIG. 9, the vehicle system 110 determines the relative richness of the motor sounds shown in FIGS. 6C and 8C, which is represented on the richness curve 902 by time T₂And (4) quoted. Vehicle with wheelsThe vehicle system 110 determines that the relative richness is now greater than the threshold 904, i.e., not richened (or richened), which results in a negative determination at step 308, and thus, the vehicle system 110 does not generate additional motor sound harmonics, but instead returns to step 302.

In another embodiment, the vehicle system 110 uses a pythagoras tuning method (not shown) to add additional steps based on a pure five degree interval. Pure intervals are intervals found in the harmonic system, with very simple frequency ratios. Pure five degrees will have a frequency ratio of 3: 2.

In another embodiment, the vehicle system 110 uses an equal law method (not shown) to add additional steps. To create rich intervals, the vehicle system 110 uses a pure major third degree comprised of a major interval and a minor interval. A full tone is considered to be exactly half of a pure third degree, and a half tone is exactly half of a full tone.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. In addition, features of various implemented embodiments may be combined to form further embodiments.

Additionally, the components and/or elements recited in any apparatus claims may be assembled or otherwise operatively configured in a variety of permutations and are therefore not limited to the specific configurations recited in the claims. Functionally equivalent processing steps may be performed in the time or frequency domain. Thus, although not explicitly stated with respect to each signal processing block in the figures, signal processing may occur in the time domain, the frequency domain, or a combination thereof. Additionally, while various processing steps are illustrated using typical terminology for digital signal processing performed in a processor, equivalent steps may be performed using analog signal processing without departing from the scope of the present disclosure. Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, any benefit, advantage, solution to problem or any element that may cause any particular benefit, advantage, or solution to occur or to become more pronounced are not to be construed as a critical, required, or essential feature or element of any or all the claims.