Exemplary embodiments of the invention are related to systems and methods for transfer function calibration of a sound augmentation system.
To enhance driver and passenger experience, some vehicles include a sound augmentation system, such as an active noise cancellation system. An active noise cancellation system attempts to reduce or eliminate unwanted sound by the addition of another sound source specifically designed to cancel or substantially reduce the unwanted sound. A sound augmentation system in a vehicle may include one or more microphones to detect sounds, an amplifier, and one or more speakers to output augmented sounds. As components in a vehicle age, they may exhibit changes in audio characteristics. For example, changes over time to components such as speakers, seals, trim attachments, headliner/microphone interface, etc. can impact transfer function characteristics of a sound augmentation system. When transfer functions used by the sound augmentation system no longer accurately reflect the characteristics of the vehicle, effectiveness of noise cancellation can diminish.
Additionally, transfer functions used for a sound augmentation system can reflect tuning characteristics that are broadly defined for a group of vehicles in order to achieve stability across a number of build variations. These transfer functions can be effective but may not be optimized to reflect characteristics specific to individual vehicles. For example, variations in trim options, engine options, transmission options, and the like can result in different audio profiles for a particular vehicle make and model.
Accordingly, it is desirable to provide systems and methods for transfer function calibration of a sound augmentation system.
In one exemplary embodiment, a vehicle system is provided that includes a sound augmentation system with a sound augmentation generator coupled to at least one audio output. The sound augmentation generator produces an augmented audio output to drive the at least one audio output based on a transfer function. The vehicle system also includes a sound augmentation system health monitor coupled to at least one audio input and a feedback of the augmented audio output. The sound augmentation system health monitor determines a current performance level of the sound augmentation system based on the at least one audio input and the feedback of the augmented audio output, and triggers a transfer function update prompt based on a difference between the current performance level and an expected performance level being at a threshold level. The vehicle system further includes a user interface that outputs the transfer function update prompt and receives a transfer function calibration request in response to the transfer function update prompt. The vehicle system additionally includes a transfer function calibration module coupled to the at least one audio output and the at least one audio input. The transfer function calibration module drives a calibration sequence on the at least one audio output and monitors the at least one audio input to determine an updated transfer function in response to the transfer function calibration request.
In another exemplary embodiment, a method of transfer function calibration for a sound augmentation system in a vehicle is provided. A sound augmentation generator of a sound augmentation system produces an augmented audio output to drive at least one audio output in the vehicle based on a transfer function. A current performance level of the sound augmentation system is determined based on a feedback of the augmented audio output and at least one audio input. A transfer function update prompt is triggered based on a difference between the current performance level and an expected performance level being at a threshold level. A transfer function calibration request is monitored in response to the transfer function update prompt. In response to receiving the transfer function calibration request, a calibration sequence is driven on the at least one audio output while monitoring the at least one audio input to determine an updated transfer function.
In a further exemplary embodiment, a vehicle includes at least one audio output to a speaker and at least one audio input from a microphone. The vehicle also includes a sound augmentation system, a sound augmentation system health monitor, a user interface, a transfer function calibration module, and a wireless interface. The sound augmentation system includes a sound augmentation generator coupled to the at least one audio output. The sound augmentation generator produces an augmented audio output to drive the at least one audio output based on a transfer function. The sound augmentation system health monitor is coupled to the at least one audio input and a feedback of the augmented audio output. The sound augmentation system health monitor determines a current performance level of the sound augmentation system based on the at least one audio input and the feedback of the augmented audio output, and triggers a transfer function update prompt based on a difference between the current performance level and an expected performance level being at a threshold level. The user interface outputs the transfer function update prompt and receives a transfer function calibration request in response to the transfer function update prompt. The transfer function calibration module is coupled to the at least one audio output and the at least one audio input. The transfer function calibration module drives a calibration sequence on the at least one audio output and monitors the at least one audio input to determine an updated transfer function in response to the transfer function calibration request. The wireless interface transmits the updated transfer function to a data collection system.
The above features and advantages and other features and advantages of the invention are readily apparent from the following detailed description of the invention when taken in connection with the accompanying drawings.
Other objects, features, advantages and details appear, by way of example only, in the following detailed description of embodiments, the detailed description referring to the drawings in which:
The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. As used herein, the term module refers to processing circuitry that may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.
In accordance with an exemplary embodiment of the invention a vehicle is shown generally at 10 in
The audio system 18, also referred to generally as system 18, drives at least one audio output 19 to one or more speakers 20. In the example of
The audio system 18 can send and receive a variety of data on the vehicle information bus 16. The audio system 18 may receive data including vehicle conditions from one or more of the modules 14, indicating operating conditions of the vehicle 10. The audio system 18 can generate outputs on the vehicle information bus 16, such as alerts or prompts, to indicate when an update of one or more of the transfer functions 30 may be needed. Alerts or prompts can be sent from the audio system 18 to a vehicle health monitor 34, which also collects vehicle health data from the modules 14. The vehicle health monitor 34 can be coupled to a user interface 36 to display status messages and/or provide an interactive health and diagnostic service interface for the vehicle 10. The user interface 36 may also receive inputs, such as a transfer function calibration request, that can be sent to the audio system 18. A transfer function calibration request can be initiated by an operator of the vehicle 10 or a service technician in response to a transfer function update prompt. The transfer function calibration request can trigger a calibration procedure that drives a sequence of tones on one or more of the speakers 20 to determine one or more updated transfer functions. Any updated transfer functions can be transmitted with an identifier of the vehicle 10 or vehicle system 12 to a data collection system 5 via a communication network 6.
The data collection system 5 can be located external to the vehicle 10, for instance, at a remotely located data collection and processing center. The data collection system 5 can log vehicle data 7 in a database 8 for further analysis. The vehicle data 7 can be accumulated for multiple vehicles, including the vehicle 10. Collection of updated transfer functions in the vehicle data 7 can enable analysis to determine how they are performing and changing over time. The vehicle data 7 can improve understanding of regional issues, specific plant builds, and/or fleet characteristics.
The communication network 6 can include any type of wired and/or wireless communication, such as a code division multiple access (CDMA) data channel. In the example of
Although a particular arrangement is depicted within the vehicle 10, the scope of embodiments is not so limited. For example, various orientation and distribution patterns of the pairings 28 can be used in the vehicle 10, as well as various numbers of speakers 20 and microphones 26 with associated inputs and outputs. Furthermore, the audio system 18 can be subdivided into multiple systems or integrated within another component or system.
The sound augmentation generator 46 produces the augmented audio output 52 to drive the at least one audio output 19 based in part on the transfer function 30 and a plurality of audio tuning parameters 58. The audio tuning parameters 58 may be received from the data storage device 32 of
The sound augmentation generator 46 can perform active noise cancellation by driving the augmented audio output 52 into an aligned gain and opposite phase relationship as a targeted noise frequency to cancel. In an active noise cancellation configuration, the sound augmentation generator 46 can establish a feedback loop relative to an audio input 24. The transfer function 30 can determine an overall shape of a frequency response relative to the audio input 24 and audio output 19 when the baseline audio output 54 is excluded. The transfer function 30 may model sound absorption and reflection properties of an interior of the vehicle 10 of
As can be seen in
In an exemplary embodiment, the sound augmentation system health monitor 42 compares the feedback 66 of the augmented audio output 52 to a level of the audio input 24 to determine a current performance level 70 of the sound augmentation system 40. The sound augmentation system health monitor 42 can determine a difference between the current performance level 70 of the sound augmentation system 40 and an expected performance level, and initiates an alert 68 upon determining that the difference is at a threshold level. The alert 68 may trigger a transfer function update prompt at the user interface 36 of
A number of thresholds 74 can be defined for performance monitoring, including an expected performance level and a threshold level. The current performance level 70 and thresholds 74 may be stored in local storage 78. The current performance level 70 can be an instantaneous value or determined over a period of time. The expected performance level can be set to a value that is beyond the typical adjustment ability of the audio tuning parameters 58 but not at a complete failure level. Adjustments to the audio tuning parameters 58 may not adequately compensate for changes in the audio characteristics of the vehicle 10 beyond a certain range, which may result in noise levels noticeably less attenuated unless the audio environment of the vehicle 10 of
The transfer function calibration module 39 is coupled to at least one audio output 19 and at least one audio input 24. The transfer function calibration module 39 can drive a calibration sequence 41 on at least one audio output 19 and monitors at least one audio input 24 to determine an updated transfer function 30A in response to a transfer function calibration request 56. The transfer function calibration module 39 can set a calibration mode 60 to control a state of the multiplexer 49 to select between the calibration sequence 41 and an output of the summing junction 50. When the calibration mode 60 is active, the calibration sequence 41 is passed through the multiplexer 49 and the amplifier 48 to the audio output 19. Effects of the calibration sequence 41 are observed by calibration logic 62 via the audio input 24. The calibration logic 62 can calculate the updated transfer function 30A by characterizing a frequency response of the calibration sequence 41 observed at the audio input 24. The updated transfer function 30A can replace transfer function 30 in the sound augmentation generator 46.
Local storage 84 can store a transfer function update history 86 that can include past values of the transfer function 30 and the updated transfer function 30A. The local storage 84 can also include a baseline transfer function 88 that represents a factory default value for restoring the transfer function 30 in case an errant determination of the updated transfer function 30A occurs, for instance, due to additional environmental noise or other factors. The updated transfer function 30A can also be sent to the wireless interface 38 (
Operation of the transfer function calibration module 39 is coordinated across the audio channels 44, such that when the calibration mode 60 is active for one audio output 19, the remaining audio outputs 19 are muted. Calibration can be initiated sequentially across multiple audio channels 44 or only performed to update a single audio channel 44. As part of a calibration process, additional system testing may be performed to ensure that system components are operable before modifying the transfer function 30. For example, open circuit and short circuit tests can be performed for the speaker 20 (
While the example of
While one example of the user interface 36 is provided in
Referring now to
In one example, the method may begin at 200. At 210, the sound augmentation generator 46 of the sound augmentation system 40 produces an augmented audio output 52 to drive at least one audio output 19 based in part on a transfer function 30. As previously described, the sound augmentation system 40 can be coupled to one or more inputs such as audio input 24, and the transfer function 30 may be defined based on a pairing 28 of one audio output 19 with one audio input 24. At 220, a feedback 66 of the augmented audio output 52 is compared to a level of at least one audio input 24 to determine a current performance level 70 of the sound augmentation system 40.
At 230, a difference between the current performance level 70 and an expected performance level of the sound augmentation system 40 is determined. At 240, if the difference is at a threshold level, then path 242 is taken to 250; otherwise, path 244 loops back to 210, where the threshold level indicates that an update of the transfer function 30 is recommended. At 250, a transfer function update prompt 106 is triggered and may be displayed on the user interface 36 or otherwise conveyed as vehicle status information. At 260, the transfer function calibration module 39 monitors for a transfer function calibration request 56 in response to the transfer function update prompt 106.
At 270, in response to receiving the transfer function calibration request 56, the transfer function calibration module 39 drives a calibration sequence 41 on the at least one audio output 19 while monitoring the at least one audio input 24 to determine an updated transfer function 30A. The transfer function 30 and the updated transfer function 30A can be defined based on a pairing 28 of one of the at least one audio output 19 with one of the at least one audio input 24. The sound augmentation system 40 may be coupled to two or more instances of the pairing 28, each having a separate instance of the transfer function 30. A separate instance of the updated transfer function 30A corresponding to each instance of the transfer function 30 can be produced. The sound augmentation system health monitor 42 can identify which pairing instance resulted in the transfer function update prompt 106. At 280, the transfer function 30 is replaced by the updated transfer function 30A. An option to revert from the updated transfer function 30A to a baseline transfer function 88 may be provided via the user interface 36.
At 290, each instance of the updated transfer function 30A can be transmitted with a system identifier to the data collection system 5. The wireless interface 38 can be used to communicate with the data collection system 5 via the communication network 6.
The method of
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the application.