Digital active road noise control method and system

An active road noise control method in an active road noise controller disposed in a vehicle may include diagnosing whether a plurality of microphones connected in a daisy chain has failed, receiving a data frame from the plurality of microphones, identifying normal information related to information included in the data frame based on a result of diagnosis, generating a digital noise control signal using the identified normal information, and transmitting the generated digital noise control signal to an external amplifier.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No. 10-2017-0148255, filed on Nov. 8, 2017, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a method and apparatus configured for reducing noise in a vehicle and, more particularly, to a digital active road noise control method and system configured for minimizing a delay time required to recognize failure of a part after a part such as a microphone has failed in the digital active noise control system.

Description of Related Art

Vehicles have evolved into entertainment and information exchange means in addition to transportation means.

With advance of vehicles and development of information communication technology, head units of currently released vehicles may be configured to perform various functions in addition to audio control functions of FM/AM, CD, etc. and an air conditioning control function. Examples of such various functions may include Bluetooth, web browsing, chatting, TV viewing, navigation, gaming, a function for capturing photos or videos, a sound storage function and a function for displaying images or videos.

To this end, vehicle manufacturers have made considerable efforts to develop hardware and software to provide more complex and multiple functions.

Conventionally, as a method of reducing driving noise generated upon driving a vehicle, various sound absorbing and insulating materials and low-noise tires have been used.

However, a road noise reduction method through hardware such as a sound absorbing and insulating material and a low-noise tire may increase costs and vehicle weight, thereby deteriorating fuel efficiency.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing a digital active road noise control method and system that substantially obviate one or more problems due to limitations and disadvantages of the related art.

Various aspects of the present invention are directed to providing a digital active road noise control method and system.

Various aspects of the present invention are directed to providing a digital active road noise control method and system configured for minimizing a delay time required to recognize failure of a part after a part such as a microphone has failed in the digital active noise control system.

The technical problems solved by the present invention are not limited to the above technical problems and other technical problems which are not described herein will become apparent to those skilled in the art from the following description.

To achieve these objects and other advantages and in accordance for an exemplary embodiment of the present invention, as embodied and broadly described herein, an active road noise control method in an active road noise controller disposed in a vehicle may include diagnosing whether a plurality of microphones connected in a daisy chain has failed, receiving a data frame from the plurality of microphones, identifying normal information related to information included in the data frame based on a result of diagnosis, generating a digital noise control signal using the identified normal information; and transmitting the generated digital noise control signal to an external amplifier.

The active road noise control method may further include receiving a reference signal from a plurality of acceleration sensors connected in a daisy chain, wherein the active road noise controller is configured to generate the digital noise control signal by further using the reference signal.

The data frame and the reference signal may be received through communication of at least one automotive audio bus (A2B).

The active road noise controller may include a first digital signal processor communicating with the plurality of microphones and a second digital signal processor communicating with the first digital signal processor.

When power is applied to the active road noise controller, the first digital signal processor may diagnose whether failure has occurred and transmits the result of diagnosis to the second digital signal processor.

The data frame may include slots corresponding in number to the number of microphones connected in the daisy chain, and the first digital signal processor may extract and transmit a slot including the normal information from among the slots included in the data frame to the second digital signal processor based on the result of diagnosis.

The active road noise controller may transmit the digital noise control signal to the external amplifier through A2B communication.

The external amplifier may include a mixing digital signal processor, and the mixing digital signal processor mixes a digital sound source signal received from a sound source digital signal processor with the digital noise control signal and transmits the mixed signal to a digital power amplifier.

According to various aspects of the present invention, an active road noise controller connected to an external amplifier for a vehicle to control active road noise may include a first digital signal processor for diagnosing whether a plurality of microphones connected in a daisy chain has failed and identifying normal information related to information included in a data frame based on a result of diagnosis upon receiving the data frame from the plurality of microphones and a second digital signal processor for generating a digital noise control signal using the identified normal information and transmitting the generated digital noise control signal to the external amplifier.

The first digital signal processor may further receive and provide a reference signal from a plurality of acceleration sensors connected in a daisy chain to the second digital signal processor, and the second digital signal processor generates the digital noise control signal by further using the reference signal.

The data frame and the reference signal may be received through communication of at least one automotive audio bus (A2B).

When power is applied to the active road noise controller, the first digital signal processor may diagnose whether failure has occurred and transmits the result of diagnosis to the second digital signal processor.

The data frame may include slots corresponding in number to the number of microphones connected in the daisy chain, and the first digital signal processor may extract and transmit a slot including the normal information from among the slots included in the data frame to the second digital signal processor based on the result of diagnosis.

The second digital signal processor may transmit the digital noise control signal to the external amplifier through A2B communication.

The external amplifier may include a mixing digital signal processor, the mixing digital signal processor may mix a digital sound source signal received from a sound source digital signal processor with the digital noise control signal to generate digital active road noise control sound, and the digital active road noise control sound may be output as an analog signal through a digital power amplifier and a speaker provided in the external amplifier.

The output analog signal may be fed back and input to the plurality of microphones.

According to various aspects of the present invention, an active road noise control system disposed in a vehicle to control road noise generated upon driving the vehicle may include an active road noise controller including a first digital signal processor for diagnosing whether a plurality of microphones connected in a daisy chain has failed and identifying normal information related to information included in a data frame based on a result of diagnosis upon receiving the data frame from the plurality of microphones, and a second digital signal processor for generating a digital noise control signal using the identified normal information, and an external amplifier for mixing the digital noise control signal with a digital sound source signal received from a sound source digital signal processor and generating and outputting digital active road noise control sound.

The aspects of the present invention are only a portion of the exemplary embodiments of the present invention, and various embodiments based on technical features of the present invention may be devised and understood by a person having ordinary skill in the art based on the detailed description of the present invention.

DETAILED DESCRIPTION

Hereinafter, an apparatus and various methods, to which the exemplary embodiments of the present invention are applied, will be described in detail with reference to the accompanying drawings. The suffixes “module” and “unit” of elements herein are used for convenience of description and thus may be used interchangeably and do not have any distinguishable meanings or functions.

FIG. 1is a diagram schematically illustrating operation of an active road noise control (ARNC) system disposed in a vehicle according to an exemplary embodiment of the present invention.

Referring toFIG. 1, the active road noise control system100may include an active road noise controller1, a microphone2, an acceleration sensor3, a sound source player4and a speaker5.

Here, it is noted that the number of microphones2, acceleration sensors3and speakers5configuring the active road noise control system100may be changed according to the design of a person skilled in the art.

The active road noise controller1may receive a noise control signal which is an error signal input to the microphone2. Here, a plurality of microphones2may be connected in a daisy chain and then connected to the active road noise controller1.

The active road noise controller1may receive road noise information collected by the acceleration sensor3, that is, a reference signal.

The active road noise controller1may generate a noise control signal using the error signal received from the microphone2and the reference signal received from the acceleration sensor3. Thereafter, the active road noise controller1may mix the noise control signal and sound output from the sound source player4, that is, a playback signal, and output the mixed signal through the speaker5.

Accordingly, the active road noise control system100according to an exemplary embodiment of the present invention may output a sound source of a reverse phase of noise coming from a road surface, reducing noise of the road surface felt by a passenger in a vehicle upon driving the vehicle.

Furthermore, the active road noise control system100according to an exemplary embodiment of the present invention can efficiently reduce noise of a road surface through software control through a digital signal processor (DSP) without using hardware such as a sound absorbing and insulating material or a low-noise tire. Furthermore, since the present invention can reduce the weight of a vehicle, fuel efficiency may be improved.

FIG. 2is a diagram showing a layout structure of a microphone and an acceleration sensor connected to an active road noise controller according to an exemplary embodiment of the present invention.

Referring toFIG. 2, first to eighth microphones231,232,233,234,235,236,237and238connected in the daisy chain may be connected to the active road noise controller210through a first automotive audio bus (A2B) (hereinafter, referred to as A2B-1).

In general, the daisy chain is a serialized data communication method and refers to the configuration of continuously connected hardware devices. For example, the daisy chain may mean a bus connection method of connecting a device A with a device B and connecting the device B with a device C upon connecting the devices A, B and C. A. At the instant time, the last device is generally connected to a resistance device or a terminal device, for example, the active road noise controller ofFIG. 2. All devices may receive the same signal but each device belonging to a chain may modify the content of one or more signals before transmission of one or more signals to another device significantly differently from a simple bus.

On an A2B single two-wire, a master-slave line topology for transmitting audio and control data along with time (clock) and power may be used.

The A2B is suitable for an in-vehicle audio application, such as a hands-free system, a voice recognition system or an active road noise cancellation system.

The active road noise controller210may be connected to left three acceleration sensors221,222and223connected in the daisy chain through a second automotive audio bus (hereinafter, A2B-2).

Furthermore, the active road noise controller210may be connected to right two acceleration sensors224and225connected in the daisy chain through a third automotive audio bus (hereinafter, A2B-3).

In general, since the acceleration sensor has large current consumption, it is preferable for system stability to connect the acceleration sensor with the active road noise controller210using a plurality of A2Bs.

Although the active road noise controller210is shown as being connected to eight microphones and five acceleration sensors in the exemplary embodiment ofFIG. 2, this is merely an exemplary embodiment and more or less microphones and acceleration sensors may be configured according to the design and configuration of the vehicle in other exemplary embodiments.

When the vehicle starts up, the active road noise controller210may diagnose whether the first to eighth microphones231,232,233,234,235,236,237and238and the first to fifth acceleration sensors221,222,223,224and225have failed through a predetermined control procedure. For example, the active road noise controller210may transmit a keep-alive message to the first to eighth microphones and the first to fifth acceleration sensors and diagnose whether a corresponding device has failed according to a response thereto.

FIG. 3is a block diagram illustrating the configuration of an active road noise control system according to an exemplary embodiment of the present invention.

Referring toFIG. 3, an active road noise control system300may include an active road noise controller310, a digital microphone/acceleration sensor320and an external amplifier330.

Here, the active road noise controller310may include an ARNC DSP311including a plurality of DSPs and a plurality of A2B communication interfaces.

The external amplifier330may include a sound source DSP331for providing a digital sound source, a mixing DSP332for mixing a digital noise control signal received from the active road noise controller310with a digital sound source signal received from the sound source DSP331to generate digital active noise control sound, and a digital power amplifier333for performing digital-to-analog conversion with respect to the digital active noise control sound, amplifying the converted signal and outputting the amplified signal through a speaker.

The active noise control sound output through the digital power amplifier333may be input to the digital microphone again to be fed back to the active road noise controller310.

The active road noise control system300may exchange a control signal and a digital data signal with the digital microphone/acceleration sensor320and the external amplifier330through the A2B.

The active road noise controller310may receive an error signal from the digital microphone through the A2B and receive a reference signal from the acceleration sensor.

The active road noise controller310may generate a digital noise control signal using the error signal and the reference signal. Here, the generated digital noise control signal may be transmitted to the mixing DSP332through A2B communication.

Since the active road noise control system according to an exemplary embodiment of the present invention performs digital communication using the A2B, it is possible to minimize wiring cost in the vehicle for signal transmission.

FIG. 4is a diagram illustrating a processing delay time in an active road noise control system according to an exemplary embodiment of the present invention.

FIG. 4shows that, among the processing times of the devices currently configuring the active road noise control system, a processing time required by the ARNC DSP is the largest at 1250 μs.FIG. 4shows that the processing performance of the ARNC DSP has largest influence on overall system performance. Accordingly, to improve overall system performance, it is important to minimize the processing delay time of the ARNC DSP.

FIG. 5is a diagram illustrating a procedure of processing microphone information in an active road noise control system according to an exemplary embodiment of the present invention.

Referring toFIG. 5, an active road noise controller520may include a first DSP521and a second DSP522.

The first DSP521may receive a data frame519from a microphone510through an A2B523port. Here, the data frame may be configured by sequentially connecting information corresponding to the first to eighth microphones511to518connected in a daisy chain, that is, error information input through the microphones. If the number of microphones connected in the daisy chain is 8, one data fame may be composed of 8 slots.

The first DSP521may assign a MIC ID524to each piece of information included in the data frame519and transmit the MIC ID to the second DSP522.

The second DSP522may generate a digital noise control signal using the data frame519received from the microphones connected in the daisy chain, that is, the error signal, and the reference signal received from the acceleration sensor.

FIG. 5illustrates the case where the information included in the data frame519are all normal, that is, the first to eighth microphones connected in the daisy chain are all normal, for example.

However, assigning the MIC ID524to the data frame519is advantageous in that it is possible to clearly determine to which microphone the information included in the data frame519corresponds. However, this may cause overall performance deterioration in a data processing time. Accordingly, it is necessary to minimize processing delay of the data frame519in the active road noise controller520.

FIG. 6is a diagram illustrating a procedure of processing a microphone signal in an active road noise control system according to another exemplary embodiment of the present invention.

FIG. 6illustrates a method of processing a data frame in an active road noise control system when at least one of the microphones connected in a daisy chain has failed.

Referring toFIG. 6, if a fifth microphone615among microphones610connected in a daisy chain has failed, information recorded in a slot619-5corresponding to the fifth microphone615of the data frame619may be abnormal. Furthermore, information recorded in slots619-6,619-7and619-8corresponding to the sixth microphone616, the seventh microphone617and the eighth microphone618disposed at the rear stage of the fifth microphone615may be abnormal.

The first DSP621may receive the data frame619from the microphone610through an S2B623port. Here, the data frame619may be configured by sequentially connecting information corresponding to the first to eighth microphones611to618connected in the daisy chain, that is, error information input through corresponding microphones.

The first DSP621may assign a MIC ID624to each piece of information included in the data frame619and transmit the MIC ID to the second DSP622.

The second DSP622may generate a digital noise control signal using the data frame619received from the microphones connected in the daisy chain, that is, the error signal, and the reference signal received from the acceleration sensor. However, the second DSP622may generate the digital noise control signal using only normal information related to the slots of the data frame619.

FIG. 7is a diagram illustrating a method of minimizing processing delay in an active road noise control system according to an exemplary embodiment of the present invention.

FIG. 7illustrates a data frame processing method in an active road noise controller for minimizing processing delay when at least one of microphones connected in a daisy chain has failed.

Referring toFIG. 7, if a fifth microphone715among microphones710connected in a daisy chain has failed, information recorded in a slot719-5corresponding to the fifth microphone715of the data frame719may be abnormal. Furthermore, information recorded in slots719-6,719-7and719-8corresponding to the sixth microphone716, the seventh microphone717and the eighth microphone718disposed at the rear stage of the fifth microphone715may be abnormal due to the properties of the daisy chain.

When power is applied to the active road noise controller720, for example, when the vehicle starts up, the first DSP721may verify whether the microphones connected in the daisy chain have failed on an A2B through a predetermined diagnosis procedure. For example, the first DSP721may verify whether the microphone has failed based on the response to the keep-alive message per microphone but this is merely an exemplary embodiment and another diagnosis procedure of verifying whether the microphone has failed is applicable according to the design of a person skilled in the art.

The first DSP721may receive the data frame719including eight slots from the microphone710through the A2B723port. Here, the data frame719may be configured by sequentially connecting information corresponding to the first to eighth microphones711to718connected in a daisy chain, that is, error information input through corresponding microphones.

The first DSP721may verify whether the microphone has failed through a predetermined control procedure. For example, as shown inFIG. 7, if the fifth microphone715has failed, the first DSP721may transmit, to the second DSP722, predetermined information (hereinafter, for convenience of description, referred to as “fifth microphone failure information”) indicating that failure of the fifth microphone715is sensed. Upon determining that the fifth microphone715has failed, the second DSP722may determine that the sixth microphone716, the seventh microphone717and the eighth microphone718disposed at the rear stage of the fifth microphone715have failed.

Upon receiving the data frame719through the A2B723port, the first DSP721may identify slots of the data frame719including normal information, based on the result of determining whether the microphone has failed. The first DSP721may transmit only slots including normal information to the second DSP722. That is, upon determining that the fifth microphone715has failed, the first DSP721may extract and transmit only the first to fourth slots719-1,719-2,719-3and719-4corresponding to the first to fourth microphones711,712,713and714from the data frame719to the second DSP722and may not transmit abnormal slots, that is, the fifth to eighth slots719-5,719-6,719-7and719-8, to the second DSP722. Based on the pre-received information indicating that the fifth microphone has failed, the second DSP722may determine that information on the slots included in the frame723received from the first DSP721corresponds to the first to fourth microphones711,712,713and714.

The first DSP721according to the exemplary embodiment may not assign the MIC ID to each piece of information included in the data frame719.

Furthermore, the first DSP721according to the exemplary embodiment ofFIG. 7may remove the slots719-5,719-6,719-7and719-8including abnormal information due to microphone failure, configure the frame723using the slots719-1,719-2,719-3and719-4including normal information and transmit the frame to the second DSP722.

Accordingly, the present invention may reduce the amount of information transmitted from the first DSP721to the second DSP722and thus minimize processing delay in the active road noise controller720.

FIG. 8is a diagram illustrating a method of minimizing processing delay in an active road noise control system according to various exemplary embodiments of the present invention.

InFIG. 8, when the active road noise control system is rebooted, for example, when the vehicle is turned off and then is turned on again, in a state in which the fifth microphone815among eighth microphones connected in a daisy chain has failed, an A2B823may recognize that only the first to fourth microphones811,812,813and814are connected in a daisy chain. In the instant case, the A2B823of the microphone810may generate and transmit data frames821and822including four slots corresponding to the four microphones811,812,813and814connected in the daisy chain to an A2B833of an active road noise controller830.

When the active road noise controller830is driven again, the first DSP831may confirm that the first microphone811, the second microphone812, the third microphone813and the fourth microphone814are normal through a predetermined diagnosis procedure. At the instant time, the second DSP832may determine that the microphone810still includes the first to eighth microphones. To solve this, the first DSP831may transmit, to the second DSP832, predetermined microphone failure information indicating that the fifth microphone832has failed.

The first DSP831may sequentially transmit a first data frame821and a second data frame822received through the A2B833to the second DSP832without any additional processing. That is, the first DSP831may bypass the data frame received through the A2B to the second DSP832without any additional processing. Accordingly, it is possible to minimize processing delay in the first DSP831.

The second DSP832may recognize that the fifth to eighth microphones815,816,817and818have failed based on microphone failure information received from the first DSP831. Accordingly, the second DPS832may confirm that the data frame received from the first DSP831includes the information slots corresponding to the first microphone811, the second microphone812, the third microphone813and the fourth microphone814.

The second DSP832may generate a digital noise control signal according to a predetermined algorithm using the information collected from the first microphone811, the second microphone812, the third microphone813and the fourth microphone814.

The first DSP831of the active road noise controller830according to the exemplary embodiment may provide the same performance, that is, the same processing delay time, with a lower clock frequency, as compared to the second DSP821ofFIG. 5.

FIG. 9is a flowchart illustrating an active road noise control method in an active road noise controller according to an exemplary embodiment of the present invention.

FIG. 9is a flowchart illustrating a data processing method for active road noise control in a DSP (hereinafter, for convenience of description, referred to as a first digital signal processor) for performing A2B communication with microphones and acceleration sensors connected in a daisy chain between two DSPs provided in an active road noise controller.

Referring toFIG. 9, when an active road noise controller is driven, a first digital signal processor may diagnose whether a plurality of microphones connected in the daisy chain has failed through a predetermined diagnosis procedure (S910).

The first digital signal processor may transmit a result of diagnosing the plurality of microphones to a second digital signal processor (S920).

The first digital signal processor may receive a data frame collected from the plurality of microphones through an A2B (S930).

The first digital signal processor may identify a slot including normal information among the slots included in the data frame and transmit the slot to the second digital signal processor (S940).

FIG. 10is a flowchart illustrating an active road noise control method in an active road noise controller according to various exemplary embodiments of the present invention.

FIG. 10is a flowchart illustrating a data processing method for active road noise control in a second digital signal processor connected to a DSP (hereinafter, for convenience of description, referred to as a first digital signal processor) for performing A2B communication with microphones and acceleration sensors connected in a daisy chain between two DSPs provided in an active road noise controller.

The second digital signal processor may receive microphone failure information including a failure diagnosis result of a plurality of microphones connected in a daisy chain from the first digital signal processor (S1010).

The second digital signal processor may receive the data frame from the first digital signal processor (S1020). Here, the data frame may include only information collected from a normal microphone.

The second digital signal processor may identify from which microphone the information included in the received data frame is collected, based on pre-received microphone failure information (S1030).

The second digital signal processor may generate a digital noise control signal using the identified information, that is, information collected through a normal microphone (S1040). The second digital signal processor according to an exemplary embodiment of the present invention may generate a digital noise control signal by further using reference signals collected from the acceleration sensors connected in the daisy chain.

The second digital signal processor may transmit the generated digital noise control signal to the external amplifier through A2B communication (S1050). At the instant time, the external amplifier may mix the digital sound source signal received from the sound source DSP with the digital noise control signal to generate digital active noise control sound, amplify the digital active noise control sound through the digital power amplifier and output the amplified digital active noise control sound through an external speaker.

Those skilled in the art will appreciate that the present invention may be conducted in other specific ways than those set forth herein without departing from the spirit and essential characteristics of the present invention.