阅读说明：本技术 音频信号产生系统及方法 (Audio signal generating system and method ) 是由 班傑明·尼尔·贝休伦 吴佳洋 于 2018-05-24 设计创作，主要内容包括：本揭示是关于播放与电动载具相关的音频信号的方法、装置以及系统。举例来说，方法包含(1)判定电动载具的速度；(2)从记忆体接收对应至所判定的电动载具速度的多个声音频率特征；以及(3)以电动载具的扬声器由所接收的声音频率特征产生音频信号片段。声音频率特征包含多个片段，每一所述片段包含动力总成(例如是电动马达)于一速度范围内产生的声音中的多个频率特征的振幅。(The present disclosure relates to methods, devices and systems for playing audio signals associated with an electric vehicle. For example, the method includes (1) determining a speed of the electric vehicle; (2) receiving from the memory a plurality of acoustic frequency signatures corresponding to the determined electric vehicle speed; and (3) generating audio signal segments from the received sound frequency signature with a speaker of the electric vehicle. The sound frequency signature includes a plurality of segments, each of which includes an amplitude of a plurality of frequency signatures in sound produced by a powertrain (e.g., an electric motor) over a range of speeds.)

1. A method for playing audio signals associated with an electric vehicle, the method comprising:

determining a speed of the electric vehicle;

receiving from a memory an audio signal segment corresponding to the determined speed of the electric vehicle, wherein the audio signal segment is generated by a plurality of sound frequency characteristics, wherein the plurality of sound frequency characteristics correspond to a sound generated by a powertrain; and

and playing the audio signal segment by a loudspeaker of the electric vehicle.

2. The method of claim 1, further comprising:

receiving from the memory the plurality of sound frequency signatures corresponding to the determined speed of the electric vehicle, wherein the plurality of sound frequency signatures comprise a plurality of segments, wherein each of the segments comprises an amplitude of a plurality of frequency signatures in the sound generated by the powertrain over a range of speeds; and

generating the audio signal segment corresponding to the received sound frequency characteristics.

3. The method of claim 1, wherein the powertrain includes an electric motor.

4. The method of claim 1, further comprising:

adjusting an amplitude of the audio signal segment based on the determined speed of the electric vehicle.

5. The method of claim 4, further comprising:

increasing the volume of the speaker when it is determined that the speed of the electric vehicle is increasing within a first speed range;

setting the volume of the speaker to a maximum when it is determined that the speed of the electric vehicle falls within a second speed range; and

when the speed of the electric vehicle is determined to be in the rise within a third speed range, the volume of the loudspeaker is reduced.

6. The method of claim 1 wherein the speed of the electric vehicle at a first point in time is a first speed of travel, wherein the audio signal segment is a first audio signal segment, wherein the method further comprises:

determining a second moving speed of the electric vehicle at a second time point;

generating a second audio signal segment based on the received sound frequency features; and

and playing the second audio signal segment by the loudspeaker of the electric vehicle.

7. The method of claim 6, further comprising:

when the first moving speed is lower than the second moving speed, the first audio signal segment and the second audio signal segment are played in a forward direction.

8. The method of claim 6, further comprising:

when the first moving speed is higher than the second moving speed, the first audio signal segment and the second audio signal segment are played reversely.

9. The method of claim 1 wherein the speed of the electric vehicle at a first point in time is a first speed of travel, wherein the audio signal segment is a first audio signal segment, wherein the method further comprises:

determining a second moving speed of the electric vehicle at a second time point; and

when the second moving speed is substantially equal to the first moving speed, the first audio signal segment is played reversely.

10. An electric vehicle, comprising:

a processor;

a power assembly coupled to the processor;

a memory coupled to the processor and configured to store a plurality of audio signal segments, wherein each of the audio signal segments is generated by a plurality of sound frequency signatures corresponding to the electric vehicle, wherein the plurality of sound frequency signatures comprises a plurality of segments corresponding to a plurality of frequency signatures in a sound generated by the powertrain; and

a speaker configured to play the plurality of audio signal segments.

11. The electric vehicle of claim 10, wherein each of the segments comprises an amplitude of the plurality of frequency features in the sound generated by the powertrain over a range of speeds, wherein the processor is configured to generate the plurality of audio signal segments based on a speed of movement of the electric vehicle and the plurality of sound frequency features.

12. The electric vehicle of claim 10, wherein the powertrain includes an electric motor.

13. The electric vehicle of claim 10, wherein the powertrain includes an electric motor, a drive belt, and a drive gear set.

14. The electric vehicle of claim 10, wherein the processor adjusts the amplitude of the plurality of audio signal segments played by the speaker based on the determined speed of the electric vehicle.

15. A method for playing audio signals associated with an electric vehicle, the method comprising:

receiving from a sound memory a plurality of sound frequency signatures corresponding to a range of speeds of the electric vehicle, wherein the plurality of sound frequency signatures comprise a plurality of segments, wherein each of the segments comprises an amplitude of a plurality of frequency signatures in a sound generated by a powertrain over the range of speeds;

determining a current moving speed of the electric vehicle;

generating a first audio signal segment corresponding to the received sound frequency characteristics;

playing the first audio signal segment with a speaker of the electric vehicle;

determining that the electric vehicle is accelerating, decelerating or maintaining the current moving speed;

based on the determination, generating a second audio signal segment corresponding to the received sound frequency features; and

and playing the second audio signal segment by the loudspeaker of the electric vehicle.

16. The method of claim 15, further comprising:

when the first moving speed is lower than the second moving speed, the first audio signal segment and the second audio signal segment are played in a forward direction.

17. The method of claim 15, further comprising:

when the first moving speed is higher than the second moving speed, the first audio signal segment and the second audio signal segment are played reversely.

18. The method of claim 15, further comprising:

when the second moving speed is substantially equal to the first moving speed, the first audio signal segment is played reversely to replace the second audio signal segment.

19. A method for generating an audio signal associated with an electric vehicle, the method comprising:

analyzing a first audio information set associated with a powertrain of the electric vehicle to identify frequency features from the first audio information set within a first range;

generating a set of corresponding frequency features within a second range based on the plurality of frequency features identified within the first range;

generating a set of audio signal segments corresponding to different speeds in the second range; and

storing the set of audio signal segments to a sound memory coupled to a processor of the electric vehicle.

20. The method of claim 19, further comprising:

determining the first range to be measured;

operating the electric vehicle within the first range, wherein the first range corresponds to a first vehicle speed range between a first speed of the electric vehicle and a second speed of the electric vehicle, wherein the first speed is lower than the second speed;

measuring a plurality of audio signals generated by the electric vehicle when the electric vehicle is operating within the first range; and

identifying the plurality of frequency features based on the measured plurality of audio signals.

21. The method of claim 20 wherein the second range corresponds to a second vehicle speed range between a third speed of the electric vehicle and the second speed of the electric vehicle, wherein the third speed is lower than the first speed.

22. The method of claim 21, wherein the first speed is about 15 kilometers per hour, wherein the second speed is about 30 kilometers per hour, and wherein the third speed is about 0 kilometers per hour.

23. The method of claim 19 wherein the set of audio signal segments are configured to be played by a speaker of the electric vehicle.

24. The method of claim 19, wherein the plurality of frequency characteristics includes a plurality of frequency characteristics curves.

25. The method of claim 19, wherein the plurality of frequency characteristics include amplitudes of fundamental, overtones, and harmonic corresponding at different vehicle speeds.

26. The method of claim 19, wherein the plurality of frequency features includes a high frequency of about 9460 hz to 10540hz, a overtone frequency of about 466 hz to 3729hz, a harmonic frequency of about 622 hz to 3322hz, and a fundamental frequency of about 233 hz.

27. The method of claim 19 further comprising determining that the frequency characteristics are based at least on a characteristic of a speaker of the electric vehicle.

28. The method of claim 19, further comprising:

adjusting the set of corresponding frequency characteristics in the second range by fading in the set of corresponding frequency characteristics over a fade-in range.

29. The method of claim 19, further comprising:

adjusting the set of corresponding frequency characteristics in the second range by fading out the set of corresponding frequency characteristics in a fading-out range.

Technical Field

The present technology generally relates to a method and system for generating an audio signal associated with an electric motor of an electric vehicle. More particularly, the present technology relates to a system for simulating sounds of an electric motor (or motor) within a speed range and playing similar sounds when the electric vehicle is operating within the speed range to alert others of the presence of the electric vehicle.

Background

Generally, electric motors are quieter in operation than conventional internal combustion engines, especially when the electric motor is just starting to operate (e.g., at a lower speed). However, under safety considerations, some countries/jurisdictions may require that electric vehicles provide certain sounds as a warning or indication of their presence. It would therefore be advantageous to have an apparatus, system, and method that satisfies the above-described needs.

Disclosure of Invention

The following summary is provided for the convenience of the reader and identifies several representative embodiments of the disclosed technology. Generally, the present technology provides an improved system and method for generating an audio signal associated with an electric motor (or a powertrain, which may have an electric motor, drive belt, drive gear set, or other suitable device driven by an electric motor) of an electric vehicle. The present technology is a way to generate and play sound that closely simulates an electric vehicle at different speeds. In one embodiment, the sound emitted by the electric motor of the electric vehicle is sampled within a sampling range that is loud enough to be detected (e.g., the electric vehicle is moving at 15 to 30 Kilometers Per Hour (KPH)). The sampled sound is analyzed and measured to identify specific frequency characteristics (e.g., to identify specific frequencies corresponding to prominent sound waves). Based on the identified frequency signature, a set of audio signals corresponding to a large target range (e.g., 0 kilometer per hour to its maximum speed) is synthesized. With this arrangement, the present technique can generate an audio signal that provides a continuous, smooth, and natural sound to the operator or other bystanders when the electric vehicle is operating at any speed within the target range. The present technology also allows the user to customize the sound of the electric vehicle to create various themes, thereby enhancing the overall user experience.

Another aspect of the present technology includes providing a method for analyzing and measuring sound (tire sound, braking, etc.) from an electric motor or other device on a vehicle. In the analysis process, the present technique can identify a plurality of dominant eigenfrequencies and harmonics thereof from the measured sounds. In some embodiments, the amplitude of the identified frequencies is plotted against vehicle speed (plot) over the audible range of speed of sound. The amplitude versus speed curve for the identified frequencies may then be interpolated or otherwise synthesized to a range of speeds at which the vehicle's sound is generally inaudible. Waveforms are generated from the interpolated or measured frequency signature, which represent the sound of the vehicle at any speed (0 to maximum speed). The present technique may extrapolate, interpolate, or otherwise adapt (fit) the identified frequency profile to produce a processed frequency profile over any range, such as the range in which the electric motor may operate, including the range in which no corresponding measured sound is present.

During operation of the vehicle, the synthesized waveform is played through the speaker so that the onlooker can hear the vehicle approaching. In some embodiments, as shown in fig. 5 and 6, the waveform is further processed with a "fade-in" or "fade-out" function, such that the artificial sound sounds natural (at lower speeds) and blends into the actual sound of the vehicle (at higher speeds).

The present technology also provides a method for playing smooth, continuous sound in response to an electric motor or other suitable device. For example, the synthesized sound file may be divided into a plurality of segments or fragments. In one embodiment, each of the segments corresponds to a particular speed (e.g., one segment or segment per speed unit, as shown in fig. 6). For example, one segment corresponds to 11 km/h, another segment corresponds to 12 km/h, and so on. Other correspondences are of course possible, for example: one segment corresponds to a range of 2 to 4 km/h, another segment corresponds to a range of 4 to 6 km/h, and so on. The present technology plays the segment or segment according to the current status of the electric vehicle (e.g. the current moving speed). To enhance the user experience of the actually generated sound, the segment is played in a manner that minimizes the sense of discontinuity. In one embodiment, as described in detail with reference to fig. 7 to 9, the clips are played forward at acceleration, backward at deceleration, and forward and backward at constant speed.

In some implementations, the disclosed techniques can generate various types of sounds based on the sound from the electric motor to provide a customized user experience. For example, the claimed technology may measure sounds from an electric motor, analyze the sounds at a plurality of fundamental frequencies, and identify characteristics of the measured sounds. The disclosed techniques may then adjust the characteristics of the sound by increasing or decreasing the amplitude of the sound wave at the fundamental frequency.

In some embodiments, the disclosed techniques may generate or simulate sound based on user operation of an electric motor. For example, when a user operates an electric motor, the requested technology may adjust the sound of the electric motor to sound like a super sports car, train, truck, other type of vehicle or device, and the like.

In some embodiments, the disclosed techniques enable a user to customize the sound of an electric motor, thereby enhancing the user experience and enjoyment of operation. For example, the user may cause the electric motor to sound like a calling (whirring) spaceship (e.g., to simulate something from the future). With this configuration, the disclosed techniques may enhance the user experience when operating an electric motor. In some embodiments, the disclosed techniques may generate simulated sounds corresponding to user actions. In such embodiments, when the user requests the electric motor to increase its output power, the requested technique may correspond to increasing the volume of the simulated sound.

In some embodiments, the sound from the electric motor or other device may be measured, analyzed, and played in real time. In such embodiments, for example, the disclosed techniques may first measure/analyze the sound of the electric motor and then generate a simulated sound in a short time. In some embodiments, the requested technology may constantly or periodically monitor the sound of the electric motor and adjust the simulated sound accordingly.

In some embodiments, the present disclosure may be implemented as a method for playing an audio signal associated with an electric vehicle. For example, the method may comprise: (1) determining a speed of the electric vehicle; (2) receiving from the memory a plurality of acoustic frequency signatures corresponding to the determined electric vehicle speed; (3) generating audio signal segments corresponding to the received sound frequency characteristics; and (4) playing the audio signal segment with a speaker of the electric vehicle. The sound frequency signature may include a plurality of segments, each of which may include an amplitude of the plurality of frequency signatures in the sound produced by the powertrain over a range of speeds.

In some embodiments, the present disclosure may be implemented as an electric vehicle. For example, an electric vehicle may include: (1) a processor; (2) a power assembly coupled to the processor; (3) a memory coupled to the processor and configured to store a plurality of acoustic frequency signatures corresponding to the electric vehicle; and (4) a speaker configured to play the audio signal segment. The sound frequency signature may include a plurality of segments, each of which may include an amplitude of the plurality of frequency signatures in the sound produced by the powertrain over a range of speeds. The processor is configured to generate an audio signal segment based on the speed of movement of the electric vehicle and the sound frequency characteristic.

In some embodiments, the present disclosure may be implemented as a system (e.g., an acoustic vehicle alert system (or an approaching vehicle audio system), abbreviated as AVAS) that emits a Vehicle Sound (VSP) to a pedestrian. In such embodiments, the system may generate a sound based on a characteristic of a powertrain of the electric vehicle when the electric vehicle is in operation. This system can improve pedestrian safety by notifying pedestrians of the presence of an electric vehicle.

Devices, systems, and methods in accordance with embodiments of the present technology may include any of the above elements, or any combination thereof. The embodiments and combinations of various elements herein are merely examples, which are not intended to limit the scope of the present disclosure.

Drawings

FIG. 1 depicts a block diagram of a system configured in accordance with a representative embodiment of the disclosed technology;

FIGS. 2A and 2B are schematic diagrams illustrating frequency signatures analyzed over a sampling range in accordance with a representative embodiment of the disclosed technique;

FIG. 3 illustrates a schematic diagram of frequency signatures generated within a target range in accordance with a representative embodiment of the disclosed technique;

FIG. 4 depicts a schematic diagram of a synthesized waveform based on generated frequency signatures, in accordance with a representative embodiment of the disclosed technology;

FIG. 5 depicts a schematic diagram of an adjusted composite waveform, in accordance with a representative embodiment of the disclosed technology;

FIG. 6 is a schematic diagram of a segment of the adjusted composite waveform of FIG. 5;

FIGS. 7, 8 and 9 are diagrams illustrating a playing method of the clip shown in FIG. 6;

fig. 10 and 11 illustrate flow charts of embodiments of the disclosed technology.

Detailed Description

FIG. 1 depicts a block diagram of a system 100 configured in accordance with representative implementations of the disclosed technology. In some embodiments, the system 100 may be an electric vehicle, such as an electric locomotive, or a system attached and connected to an electric vehicle. The system 100 includes a processor 101, a memory 103 coupled to the processor 101, an electric motor 105 (or a powertrain having an electric motor and other driving elements/devices such as belts, chains, gear sets, etc.) configured to move the system 100, a battery 107 configured to power the electric motor 105, one or more sensors 109, and a communication component 115. The processor 101 may control other components within the system 100. The memory 103 may store instructions, signals, or other information related to the system 100. Battery 107 provides power to electric motor 105 such that electric motor 105 can move system 100. The sensor 109 is configured to measure and/or monitor components and operational characteristics of the system 100. In some embodiments, the sensor 109 may include: audio sensors, fluid pressure sensors, temperature sensors, velocity sensors, position sensors, gyroscopes, moment sensors, etc. The communication component 115 is configured to communicate with other devices or systems (e.g., a user's smart phone, a server servicing the system 100, a battery exchange station/kiosk, a vehicle, etc.) via one or more wireless connections. The wireless connection is, for example, a Wide Area Network (WAN), a Local Area Network (LAN), or a Personal Area Network (PAN).

The system further comprises a sound memory 111, a sound processing part 113 and a loudspeaker 117. The audio memory 111 is configured to store digital audio signals or audio information associated with the system 100. The sound processing component 113 is configured to adjust sound associated with the system 100. The speaker 117 is configured to play sound or audio signals associated with the system 100 to the operator 10, the pedestrian 11, and/or the driver/passenger of the vehicle 12. In some embodiments, the speaker 117 may be configured to play sound in a particular direction (e.g., the direction in which the system 100 is moving).

In some embodiments, the sensor 109 comprises a speedometer (or GPS sensor) that detects the speed of the system 100. The measured speed is transmitted to the processor 101, and the processor 101 is programmed to retrieve a sound clip (e.g., a digital audio file) stored in the memory 103 or the sound memory 111 corresponding to the speed and provide the sound clip to the sound processing part 113, which adjusts the sound clip to be played through the speaker 117. As discussed in further detail below, depending on the computing power of the system 100, the synthesized vehicle sounds (i.e., the sound segments) may be pre-loaded into the sound memory 111 by analysis performed in a remote laboratory or calculated/determined by the processing device of the system itself.

To generate a sound clip/sound file (e.g., a digital audio wav file) representing the sound of the system 100 within its operating speed range, the actual sound of the system is recorded within a speed range in which it can be heard. In one embodiment, sound is recorded at a speed range (e.g., a speed range of 15 to 30 kilometers per hour) at which the system 100 generates a distinct audible signal that can be sensed by the microphone. In some embodiments, the sampling range may be an operating range of the electric motor 105 (e.g., 1000 to 3000 revolutions per minute (rpm)).

The sound of the system 100 over a sampling range is stored in digital memory and analyzed in the frequency domain to identify the dominant frequency (dominant frequency) of the electric motor and the harmonics (harmonics) that characterize the sound of the electric motor. The amplitude of the frequency component (frequency component) generally varies with the speed of the vehicle. For example, as shown in fig. 2A, the fundamental frequency measured by an electric motor operating at 30 km/h is about 233Hz, and significant harmonic overtones (overtones) are measured at 466, 932, 1864, and 3729Hz, while partial harmonics are measured at 622, 739, 830, 1108, 1661, 2217, 2489, 2960, and 3322 Hz. In other embodiments, the sound of the electric motor may be measured at multiple sets of fundamental frequencies, depending on factors such as the characteristics of the electric motor.

The frequency of the detected signal decreases with decreasing speed or revolutions per minute. The frequency of the detected component is plotted against the vehicle speed (or revolutions per minute of the electric motor) to produce a series of curves as shown in fig. 2A and 3. Based on the identified frequency signature, the curves are analyzed to predict what frequency components are within a range that is typically inaudible to the sound produced by the system when in actual use (e.g., on the street). For example, a target range for the predicted sound may be determined for a speed range (e.g., from stationary to maximum speed) at which the system 100 operates.

In some embodiments, the frequency versus speed plot is analyzed by curve fitting methods (e.g., interpolation, spline interpolation, polynomial fitting, etc.) to predict the frequency components of the electric motor and its harmonics and overtones at speeds that are inaudible to sound in use. Once the profile is fitted to the entire speed range of the system 100, a sound file, such as a WAVE file, is created for the entire speed range. Such files may be relatively short, allowing them to be stored in inexpensive memory of the system 100. The synthesized WAVE file may then be used to produce sound that is played by speaker 117.

In some embodiments, the sound processing component 113 may further adapt the synthesis of the set of audio signals for customizing the user experience. For example, the sound processing component 113 may fade in the set of audio signals with a parabolic function and/or fade out the set of audio signals with a linear function (as shown in fig. 5).

In some embodiments, the sound file is divided into a plurality of segments. For example, each such segment may correspond to a particular range of speeds (e.g., 1 kilometer per hour). The segments may be generated and stored in the audio memory 111 for further use. For example, the processor 101 may be programmed to play the stored segment corresponding to the current moving speed of the system 100.

In some embodiments, the stored segment may be played forward or backward to provide a natural sound to the user. In some embodiments, the playing direction of the stored segment is determined according to the change of the moving speed (e.g. acceleration or deceleration). Details of such embodiments are discussed below with reference to fig. 7-9.

In some embodiments, the creation of the sound file (i.e., the sound signal segment) representing the sound of the system 100 (e.g., the vehicle) is done in the laboratory based on the recording of the vehicle. The sound file is then stored in the carrier during manufacture. In other embodiments, the sound file of the vehicle may be included in a software update to the existing vehicle via a wired or wireless connection (e.g., via a smartphone connected to the vehicle). In still other embodiments, the sound file may be generated on the carrier depending on the processing power available on the carrier (e.g., the processing power of the processor 101 shown in fig. 1). For example, the vehicle may include a microphone configured to detect sounds generated when the user is instructed to drive at a particular speed. The sounds are recorded, stored in memory, and analyzed by a signal processor on the vehicle to produce sound files in a manner similar to that performed in a laboratory. The generated segments may then be stored in the audio memory 111, and the speaker 117 may then play the segments in the manner described above. In some embodiments, the fragments may be stored as firmware of the system 100.

Fig. 2A and 2B are schematic diagrams illustrating frequency signatures analyzed over a sampling range according to representative embodiments of the disclosed technology. In FIG. 2A, three different types of frequencies are identified within a sampling range of 15 to 30 kilometers per hour.

The most significant frequencies can be identified as the fundamental frequency and its overtones and half-harmonics, and the high frequency components can also be identified, but in one embodiment the high frequency components are ignored. In the illustrated embodiment, the fundamental frequency is the most significant frequency (e.g., the largest amplitude of the sound waves at all frequencies) in the sampling range. As shown in fig. 2A, at 30 km/h, the fundamental frequency is about 233 Hz.

The "overtone" category refers to sound waves that can form overtones of a fundamental frequency (e.g., any vibration having a frequency that is an integer multiple of the fundamental frequency, without the fundamental frequency). In the illustrated embodiment, the overtones may range from 466 to 3729 Hz.

The "half-harmonic" category refers to sound waves that form harmonics of a fundamental frequency (e.g., any vibration having a frequency that is an integer multiple of the fundamental frequency, including the fundamental frequency). In the illustrated embodiment, the half-harmonic may range from 622 to 3322 Hz.

As shown in fig. 2A, the frequency signature is plotted or analyzed as a frequency signature curve. The identified frequency signature shown in fig. 2A is used to generate frequency signatures over a range of speeds that are typically inaudible to a vehicle. In this way, the frequency characteristics generated in the target range can retain the main characteristics of the original sound source (e.g., the electric motor 105). Thus, the generated frequency signature can be used to simulate the sound produced by the original sound source.

FIG. 3 illustrates a schematic diagram of frequency signatures generated within a target range in accordance with a representative embodiment of the disclosed technology. In the illustrated embodiment, the target range is a speed range of 0 to 30 kilometers per hour. As shown, the generated frequency signature is a pattern of frequency signatures. The curves shown in FIG. 3 may be generated from the curves in FIG. 2A by extrapolation, interpolation, curve fitting, and/or other suitable algorithms. In some embodiments, the generated frequency signature may be formed based on empirical studies (e.g., studies based on user experience). As shown, the range covered by the curve generated in fig. 3 (e.g., 0 to 30 km/h) is greater than the curve of fig. 2A (e.g., 15 to 30 km/h). Thus, the curve generated in FIG. 3 may be used to generate sounds that sound like the original sound source (e.g., the powertrain of a vehicle incorporating system 100) within a target range that is greater than the sampling range.

Once the frequency versus speed curve for the overall expected operating speed of the vehicle is determined, a sound file is generated accordingly. The sound file may be quite short depending on the fidelity required, the speakers to be used, and other audio engineering factors. In one embodiment, a 1.8 second sound file is sufficient to store sound representing an electric locomotive at a speed in the range of 0 to 30 kilometers per hour. The sound file reproduces the frequencies of the different frequency components at each velocity.

FIG. 4 depicts a schematic diagram of a synthesized waveform based on generated frequency characteristics, in accordance with a representative embodiment of the disclosed technology. The synthesized waveform may be generated by synthesizing or combining sound waves of multiple frequency classes (e.g., the "fundamental", "overtone", and "semi-harmonic" classes described above).

In the illustrated embodiment, the synthesized waveform is generated by combining waves from the "overtone" and "semi-harmonic" categories with equal weights in amplitude (e.g., half for each category). In other embodiments, the composite waveform may be generated by combining different classes in different proportions, depending on a number of factors, such as providing different audio themes to the user.

FIG. 5 depicts a schematic diagram of an adjusted composite waveform, according to a representative implementation of the disclosed technology. In some embodiments, the synthesized waveform of fig. 4 can be further adjusted during playback. The amplitude of the envelope (envelope) of the synthesized waveform corresponds to the volume of the loudspeaker when the audio signal is played. In the illustrated embodiment, the synthesized waveform can be adjusted by "fading in" at a first range of speeds from 0 to 14 kilometers per hour, a flat response (flat response) at about 14.5 to 23.5 kilometers per hour, and a linear decay in waveform amplitude at 23.5 to 30 kilometers per hour based on a parabolic function. For example, this may result in a naturally sounding vehicle that mimics how vehicle sound increases as speed rises, and then reduces the contribution of the synthesized sound as the vehicle's actual sound is heard. The increasing waveform provides a fluent sound to the user or bystanders. Within a second range of speeds (e.g., 14.5 to 23.5 km/h), the composite waveform may be played at maximum volume. In a third speed range (e.g., 23.5 to 30 km/h), as the vehicle's natural sound increases with speed, the synthesized waveform may be adjusted by "fading" based on a linear function. Thus, to provide a smooth, natural user audio experience, the present technology can fade out the waveform in the third speed range. In other embodiments, the composite waveform may be adjusted by other suitable functions. The first, second and third speed ranges may vary based on the volume of the sound generated by the vehicle itself. For example, if the vehicle with a quieter powertrain generates sound large enough to be noticed by pedestrians only when the vehicle speed exceeds 60 km/h, the first, second, and third speed ranges may be set to 0 to 20 km/h, 20 to 40 km/h, and 40 to 60 km/h.

FIG. 6 is a diagram illustrating a segment of the adjusted composite waveform of FIG. 5. The composite waveform may be divided into a plurality of audio signal segments. In one embodiment, a speed difference of 1 km per hour corresponds to a 60 ms segment of the audio file. As shown, the composite waveform is divided into segments (e.g., one segment per speed unit) based on the speed of movement of the system or electric vehicle. The segment corresponding to the detected vehicle speed is played through a speaker on the vehicle.

Fig. 7, 8 and 9 are schematic diagrams illustrating a playing method of the clip shown in fig. 6. Depending on the speed of the vehicle, the disclosed techniques may play the segment in a normal (e.g., forward) direction/form or in reverse.

In one embodiment, the speed of the vehicle is detected at a time rate that is the same as the length of the audio file (e.g., every 60 milliseconds). If the speed of the carrier is increased, the corresponding audio clip is played forward. If the detected carrier speed is reduced, the corresponding audio clip is played reversely. In one embodiment, to avoid significant audio discontinuities when the vehicle is held at a constant speed, the audio clips are played in the forward and reverse directions, and vice versa.

In the embodiment shown in fig. 8, when the electric vehicle moves at a constant speed, the audio clip may be played first in the forward direction and then in the reverse direction (e.g., reverse direction). The process then repeats as long as the vehicle maintains the same speed. This configuration provides a smooth waveform (e.g., compared to the start-to-end play segment and then start-over as shown in fig. 7).

In some embodiments, when the electric vehicle is accelerating, all segments can be played in a normal manner (e.g., as shown in fig. 9, the speed is increased from 24 km/hour to 26 km, segments corresponding to 24 km/hour are played in a forward direction, segments corresponding to 25 km/hour are played in a forward direction, and so on). In some embodiments, when the electric vehicle decelerates, the next segment may be played back in reverse (e.g., as shown in fig. 9, the speed decreases from 26 km/hour to 24 km/hour, the segment corresponding to 26 km/hour is played back in reverse, then the segment corresponding to 25 km/hour is played back in reverse, and so on). With this configuration, the disclosed techniques can play the entire waveform in a smooth and continuous manner to enhance the user experience.

Fig. 10 is a flow chart of a method 1000 for generating an audio signal associated with an electric motor of an electric vehicle (e.g., for simulating a sound of the electric motor while operating the electric motor). In some embodiments, the method 1000 may be implemented in a system (e.g., the system 100) of the present disclosure. In some embodiments, the method 1000 may be implemented in an electric vehicle. In some embodiments, the method 1000 may be used to configure a vehicle sound system. For example, the vehicle sound system may include a processor and a sound memory/storage device coupled to the processor. In such embodiments, the method 1000 may generate an audio clip based on the analysis (e.g., the embodiments discussed herein with reference to fig. 1-2B) and store it in the audio memory. Once completed, the audio clips stored in the audio memory can be used (e.g., played by speakers of the vehicle audio system).

As shown in fig. 10, the method 1000 first analyzes a first set of audio information associated with an electric motor to identify a plurality of frequency characteristics of the audio information within a first range at block 1001. In some embodiments, the first set of audio information may be measured by an audio sensor (e.g., a microphone). In some embodiments, the frequency signature includes sonic waves at a plurality of frequencies (e.g., as discussed above with reference to fig. 2A and 2B). In some embodiments, the first range may be a sampling range (e.g., a sampling range determined by a vehicle speed or an electric motor speed). In some embodiments, the frequency characteristic may be in the form of a frequency characteristic curve/line. In some embodiments, the frequency characteristics may include amplitudes of fundamental, overtones, and harmonic at different vehicle speeds. In some embodiments, the frequency characteristics may include a high frequency ranging from about 9460 to 10540Hz, a harmonic frequency ranging from about 466 to 3729Hz, a harmonic frequency ranging from about 622 to 3322Hz, and a fundamental frequency of about 233 Hz. In some embodiments, the frequency characteristic may be determined based on at least one characteristic of a speaker of the electric vehicle (e.g., such that a corresponding audio clip may be played well at this speaker).

At block 1003, the method 1000 then generates a corresponding set of frequency features in the second range based on the plurality of frequency features identified in the first range. In some embodiments, the second range may be a vehicle speed range, and the second range (e.g., 0 to 30 km/h) is greater than the first range (e.g., 15 to 30 km/h). At block 1005, the method 1000 then generates a set of audio signal segments corresponding to different vehicle speeds in the second range. In some embodiments, the audio signal segment may be the segment discussed above with reference to fig. 6 (e.g., a set of sound waves corresponding to a vehicle speed range). At block 1005, the method 1000 then stores the set of audio signal segments in an audio memory coupled to a processor of the electric motor. The processor is configured to control or communicate with the electric motor. In some embodiments, the processor may be an engine control unit. Once the audio signal segments are stored in the audio memory, they can be played back when the operator is operating the electric vehicle (e.g., simulating the sound of an electric motor).

In some embodiments, the method 1000 may further include (1) determining a first range to be measured; and (2) operating the electric vehicle within the first range. The first range may correspond to a first vehicle speed range between a first speed of the electric vehicle (e.g., 15 kilometers per hour) and a second speed of the electric vehicle (e.g., 30 kilometers per hour). The method 1000 may also include (1) measuring an audio signal generated by the electric motor while the electric motor is operating in the first range; and (2) identifying a plurality of frequency features based on the measured audio signal. In some embodiments, the second range may correspond to a second vehicle speed range between a third speed of the electric vehicle (e.g., 0 kilometers per hour) and a second speed of the electric vehicle (e.g., 30 kilometers per hour).

In some embodiments, the method 1000 may include adjusting the corresponding set of frequency features in the second range by fading in the corresponding set of frequency features in the "fade-in" range or the "fade-out" range. Embodiments of the "fade-in" and "fade-out" features are discussed above with reference to the sound processing component 113 and fig. 5.

Fig. 11 is a flow chart of a method 1100 for playing an audio signal associated with an electric vehicle (e.g., simulating the sound of a powertrain, specifically, simulating the sound of an electric motor). In some embodiments, the method 1100 may be implemented in a system (e.g., the system 100) of the present disclosure. In some embodiments, the method 1100 may be implemented in an electric vehicle. In some embodiments, the method 1100 may be used to configure a vehicle sound system. For example, the vehicle sound system may include a processor and a sound memory/storage device coupled to the processor. In these embodiments, the method 1100 may play the pre-stored audio clip through the speakers of the vehicle sound system.

At block 1101, the method 1100 first determines a speed of the electric vehicle. In some embodiments, the measurement of the speed may be accomplished by a speed sensor or speedometer. At block 1103, the method 1100 then receives an audio signal segment corresponding to the determined vehicle speed from a memory (e.g., an audio memory as discussed herein). The audio signal segment is generated from a plurality of sound frequency characteristics corresponding to the determined vehicle speed. Specifically, the audio signal segments are generated by a plurality of sound frequency characteristics that correspond to the sound generated by the powertrain over a range of speeds. In some embodiments, the sound frequency signature may include a plurality of segments, each of which may include an amplitude of a plurality of frequency signatures of sound generated at different speeds at an electric motor speed over a range of speeds (e.g., a range of speeds at which an electric vehicle may operate). The generation of the audio signal segments may refer to the embodiments described with reference to fig. 1 to 4. At block 1105, the method 1100 then plays the audio signal segment corresponding to the received audio frequency signature with a speaker of the electric vehicle.

In some embodiments, the method 1100 may adjust the amplitude of the audio signal segment based on the determined electric vehicle speed. In other words, the speaker can play different audio clips at different carrier speeds. For example, as described with respect to the embodiment of fig. 5, when the speed of the electric vehicle is increased from the first speed range to the second speed range and the third speed range, the speaker not only plays different audio segments corresponding to different vehicle speeds, but the volume/amplitude of the speaker is also adjusted from increasing (e.g., fading in based on a parabolic function) to a maximum volume, then decreasing (e.g., fading out based on a linear function), and vice versa. In some embodiments, the method 1100 may play the audio clip in a number of ways. For example, in some implementations, the method 1100 may play audio clips forward/backward. In some embodiments, the method 1100 may play the segment forward when the electric vehicle is accelerating. In some embodiments, the method 1100 may reverse the segment as the electric vehicle decelerates. In some embodiments, the method 1100 may repeat the playback of the same segment in the forward and reverse directions when the speed of the electric vehicle is substantially constant (e.g., 10% or more). Embodiments of forward/reverse playing audio clips are described in detail with reference to fig. 7 to 9.

In some embodiments, the audio clip may be stored in a sound memory or storage device. When the system wants to play an audio clip, the system can retrieve the audio clip from the audio memory. In some embodiments, the system may retrieve audio clips (e.g., the most frequently played ones) and then store them in a cache coupled to or within the processor so that the audio clips can be played quickly and efficiently.

From the foregoing, it will be appreciated that specific embodiments of the techniques described herein are provided for illustration only, and that various modifications may be made without deviating from the techniques described. Moreover, while advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also have, and not all embodiments need, have such advantages to fall within the scope of the technology. Accordingly, the present disclosure and its related art may encompass other embodiments not explicitly shown or described herein.