WO2020007529A1

WO2020007529A1 - Emergency call system of a motor vehicle

Info

Publication number: WO2020007529A1
Application number: PCT/EP2019/063396
Authority: WO
Inventors: Simon Bork
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2018-07-03
Filing date: 2019-05-23
Publication date: 2020-01-09
Also published as: EP3818509B1; EP3818509A1; DE102018210934A1

Abstract

An emergency call system of a motor vehicle comprises a digital microphone that is connected to a bus master via an automotive audio bus and is actuated by said bus master to provide a prescribed directional characteristic, wherein - the digital microphone has at least two microphone capsules, - the at least two microphone capsules are arranged symmetrically with respect to one another, - the digital microphone is arranged ahead of the location of the driver and the location of the passenger in the direction of travel, and - in the event of failure of the bus master, two microphone capsules are interconnected in series with one another with the incorrect polarity, so that a common figure-of-eight characteristic is produced, and the common signals from the digital microphone are routed out for further processing.

Description

description

Emergency call system of a motor vehicle

The invention relates to an emergency call system in a motor vehicle according to the preamble of claim 1.

In the course of digitization, the automotive audio bus, abbreviated A ² B or A ² Bus, will increasingly be used in motor vehicles, with which it is possible to use digital microphones. The digital microphones have the option of realizing a beamformer and thus implementing a speaker distinction in the vehicle according to the driver and front passenger, beamforming meaning that the digital microphone has an intended directional characteristic.

It is currently planned that the bus master, and thus also the calculation of the

Beamformers, is taken over by the infotainment system. If the bus master is no longer active, for example, the infotainment system fails in the event of an accident, and beamforming no longer takes place. In this case, only one of the digital microphones is used, which then no longer has a directional characteristic due to lack of control and is therefore omnidirectional, that is to say has a spherical characteristic.

However, this is counterproductive for the implementation of emergency call systems in vehicles, since the emergency loudspeaker can sound back into the microphone due to the omnidirectional characteristic of the microphone.

Document DE 10 2015 205 686 A1 relates to an emergency reporting device in a motor vehicle for the manual and / or automatic reporting of an emergency to a reporting center, with at least one hands-free communication device consisting of at least one microphone and at least one loudspeaker for communication with a reporting center is usable. It is proposed that the at least one microphone be arranged in a first level and the at least one loudspeaker separately from the microphone in a second level. The second level is in one ordinary direction of travel of the motor vehicle behind the first level. Furthermore, the at least one microphone has at least one area higher or highest

Input sensitivity and at least a range lower or lowest

Input sensitivity. The microphone faces the area of lower or lowest input sensitivity of the second level. With such an arrangement, good acoustic decouplings between the microphone and loudspeaker can be achieved and good acoustic properties of the emergency reporting device can be achieved.

The publication DE 10 2010 034 237 A1 provides a microphone system for a motor vehicle, which comprises a plurality of microphone devices distributed in the motor vehicle, each of which has at least one microphone with a predetermined directional characteristic. The microphone system further comprises at least one data transport network and at least one central processing unit. The microphone devices, which are connected to the data transport network, each have a clock generator and are designed to output a digital signal. The central processing unit has a clock generator and is communicatively coupled to the data transport network, with the central

Computing unit an algorithm for calculating at least one directivity of the microphones from the digital signals can be executed. The data transport network is a digital vehicle bus system that transmits the digital signals from the microphone devices to the central processing unit, at least one of the components

Microphone devices and central processing unit comprises a synchronization device for clock synchronization of the clock generators.

The document DE 10 2013 019 194 A1 relates to a microphone device for detecting a sound signal in a motor vehicle. At least two microphones are connected to a processing circuit and in a first processing mode a digital output signal is generated which contains each microphone signal individually. A coupling unit sends the output signal over a communication bus. The coupling unit is designed to receive at least one predetermined control command via the communication bus and to output it to a control device of the processing circuit, which is designed to, depending on the at least one control command, the

Switching processing circuit between the first processing mode and a second processing mode, wherein the output signal generated in the second processing mode differs from the output signal generated in the first processing mode. The publication DE 10 2007 014 816 A1 relates to a communication system in one

Vehicle which has at least two microphones and loudspeakers which are arranged in a vehicle at the interfaces of the interior. In each case one loudspeaker and at least one microphone are combined in a compact electroacoustic structural unit, which can simultaneously contain an amplifier unit. The electroacoustic assembly is connected via an electrical transmission path to at least one other similar electroacoustic assembly, the electroacoustic

Units each have at least one microphone with a directional characteristic with bipolar sinks. In order to achieve a compact electro-acoustic unit, the loudspeaker and the microphone are designed to be spatially closely adjacent, whereby to avoid

Feedback between the microphone and the adjacent speaker of this or

whose acoustic radiation is in the area of the bipolar sinks of the microphone.

The invention is therefore based on the object of realizing an emergency call system in a digital microphone of a motor vehicle with a directional characteristic, in which

Noise can be reduced.

This object is achieved by an emergency call system with the features of claim 1. Preferred embodiments of the invention are the subject of the dependent claims.

The emergency call system of a motor vehicle according to the invention comprises a digital microphone which is connected to a bus master via an automotive audio bus, in short A ² bus, and is controlled by the latter to provide a predetermined directional characteristic, wherein

the digital microphone has at least two microphone capsules,

the at least two microphone capsules are arranged symmetrically to one another, the digital microphone is arranged in the direction of travel in front of the location of the driver and the location of the front passenger, and

in the event of a failure of the bus master, two microphone capsules are connected in reverse polarity to one another so that a common eight characteristic is generated and the common signals are led out of the digital microphone for further processing. By generating an eight characteristic of the two polarity-reversed microphone capsules, at least a sufficient orientation towards the driver and the front passenger is achieved, so that in an emergency, if the bus master and thus the entire A ² bus fails, the emergency call center can receive both the driver and, if necessary Passenger is better.

The at least two microphone capsules are preferably arranged in a horizontal plane of the vehicle, it being possible in particular for the two microphone capsules to be arranged symmetrically to the longitudinal axis of the vehicle. This improves the separation between driver and front passenger, as the figure-eight characteristic is symmetrical to the

Vehicle longitudinal axis extends.

The bus master is preferably implemented by an infotainment system of the motor vehicle, as a result of which a separate bus master is unnecessary.

More preferably, the common signals of the two polarity-reversed microphone capsules are fed directly to an online connection unit for further processing, the online connection unit providing access to an emergency call center in the event of an emergency and the online connection unit feeding the common signals of the microphone capsules to the emergency call center ,

The emergency call system further preferably has at least one emergency loudspeaker so that the emergency call center can communicate with the driver or the passenger in an emergency.

The emergency loudspeaker is preferably on the axis of symmetry of the two

Microphone capsules arranged in the direction of travel of the vehicle in front of the microphone capsules. In this way, sound entries by the emergency loudspeaker on the polarity-reversed microphone capsules are minimized.

In another embodiment, the emergency loudspeaker is arranged in the defrost channel of the vehicle, whereby a more diffuse sound field is generated in connection with the microphone and the eight characteristic.

Furthermore, the emergency loudspeaker can be arranged on the instrument panel in the center position or behind the driver and front passenger. Furthermore, between the polarity reversed microphone capsules and the

Emergency loudspeaker a corresponding distance and thus an acoustic runtime be available, so that in the downstream digital signal processing

Echo cancellation can be enabled.

A preferred embodiment of the invention is explained below with reference to the drawings. It shows

1 shows a digital microphone system with A ² B bus,

2 shows the beamforming of the digital microphone system with a focus on the driver and front passenger,

3 shows the use of the digital microphone system as an emergency call,

Fig. 4 shows the eight characteristic of the microphone system in an emergency, and

Fig. 5 shows the arrangement of an emergency speaker in the microphone system in connection with an emergency.

1 shows a digital microphone 1 arranged in a motor vehicle (not shown), which is connected to an infotainment system 2 of the motor vehicle via a bus 3. The automotive audio bus, or A ² bus for short, is used as bus 3, with the infotainment system 2 also taking on the role of the bus master in this example. With a digital microphone, a beamformer can be realized, whereby a

Speaker distinction between driver and passenger is possible because the

Reception characteristics of a digital microphone is controllable and as a function of

Solid angle can be changed.

In the example of FIG. 1, the digital microphone 1 comprises three microphone capsules 4, 5 and 6, each taking into account their polarities “+” and via connections 4+, 4-, 5+, 5-, 6+ and 6- to one A / D converter 7 are connected, in which the conversion of the analog signals of the microphone capsules 4, 5, 6 into digital signals. The three microphone signals of the A / D converter 7 are fed to an A ² B interface 8, which places the digital microphone signals on the A ² bus 3.

The A ² bus 3 feeds the digital microphone signals to the infotainment system 2 via an A ² B interface 9 for further processing. The infotainment system 2 has a beamforming device 10 which generates control signals by means of which the

Directional characteristic of the digital microphone 1 can be set. These control signals are supplied to the digital microphone 1 by the infotainment system 2 via the A ² bus 3.

FIG. 2 shows the beamforming, that is to say the generation of a specific directional characteristic 11 by the digital microphone 1 in detail, only the three being shown for the sake of simplicity

Microphone capsules 4, 5 and 6 of the digital microphone 1 with their connections 4+, 4-, 5+, 5-, 6+ and 6- are shown. By the described in connection with FIG. 1

Activation of the digital microphone 1 with its three microphone capsules 4, 5, 6, a specific directional characteristic 11 can be achieved with the two lobes 12 and 13 shown, one lobe 12 aimed at the driver 14 and the other lobe 13 aimed at the passenger 15 , In this way, the infotainment system 2 shown in FIG. 1 can make a selection between driver 14 and front passenger 15.

If the bus master embodied by the infotainment system 2 is no longer active, which can be the case if, for example, the infotainment system 2 fails in the event of an accident, beamforming no longer takes place and the specific directional characteristic 11 of the digital microphone 1 is lacking corresponding control is no longer available. Even if the digital microphone 1 is still active, in the event of an accident it is no longer possible to differentiate between driver 14 and front passenger 15, since the digital microphone 1 no longer has a directional characteristic and is therefore omnidirectional, i.e. has a spherical characteristic, the spherical characteristic for each Microphone capsule 4, 5, 6 applies. However, for the implementation of emergency call systems in vehicles

counterproductive, since the emergency loudspeaker can ring back into microphone 1. It is also conceivable that the three microphone capsules 4, 5 and 6 after decoupling from

Infotainment system 2 have a different directional characteristic, for example a cardioid characteristic.

FIG. 3 shows the digital microphone 1 and its connection to the infotainment system 2 analogously to FIG. 1, the same reference symbols having the same meaning as in FIG. 1 have, so that for their explicit explanation reference is made to FIG. 1. In addition to the infotainment system 2, there is an online connection unit 20 which also has access to the A ² bus via an A ² B interface 21 and which connects to the outside world via mobile radio.

If the bus master implemented by the infotainment system 2 is used for the

Calculation of the beamformer is responsible, are no longer available, two of the three microphone capsules 4, 5, 6 are connected with reverse polarity.

In the case shown, therefore, in the illustration in FIG. 3, in the event of a fault, the upper microphone capsule 4 is connected to the lower microphone capsule 6 in reverse polarity. This is realized by the negative connection 6- of the lower microphone capsule 6 being led out via a connection 19 and the positive connection 6+ of the lower microphone capsule 6 being connected via a connection 17 to the negative connection 4- of the upper microphone capsule 4 and the signals of the poritive connection 4+ of the upper microphone capsule 4 is led out of the digital microphone 1 via a further separate connections 18. The common signals lying on the outgoing connections 18 and 19 of the polarity-reversed microphone capsules 4, 6 are fed to an online connection unit 20, in which the common signals are further processed. These analog signals of the polarity-reversed microphone capsules 4, 6 can be forwarded in the online connection unit 20 in an analog manner or they are converted into digital signals via an A / D converter (not shown) and as such in an emergency to a remote receiver by radio transfer.

The online connection unit 20 can also be connected to the A ² bus 3 via an A ² B interface 21 and, in the undisturbed case, can be used to transmit the digital information from the digital microphone 1 to the outside world.

It is also possible that in the event of a failure of the infotainment system 2, the online connection unit 20 can also implement the bus master and take over the beamfroming. If the computing capacity for calculating the beamforming in the online connection unit 20 is not sufficient, the online connection unit 20 can still control the A ² bus and use the microphone signals in digital form from the A ² bus, since all signals are still present. By simply negating a microphone signal from the microphone 6 and then adding it to the microphone signal 4. The designations "top" and "bottom" refer to the arrangement shown in FIG. 3. As can be seen from the illustration in FIG. 2, the digital microphone 1 with the microphone capsules 4, 5 and 6 is arranged in front of the driver 14 or front passenger 15. Therefore, in the vehicle plane, the upper microphone capsule 4 is arranged on the left side of the vehicle, the middle microphone capsule 5 in the vehicle center and the lower microphone capsule 6 on the right side of the vehicle.

Fig. 4 shows the effect of the reverse polarity serial connection of the two microphone capsules 4 and 6. As already explained in connection with FIG. 3, the positive termination 6+ of the lower, ie in the direction of travel right microphone capsule 6 with the neat connection 4- der Upper microphone capsule 4, that is to say on the left in the direction of travel, and the negative connection 6- of the lower microphone capsule 6 and the positive connection 4+ of the upper microphone capsule are brought out as connections 18 and 19. Since there is no control of the two microphone capsules 4 and 6 due to the lack of a bus master, each microphone capsule 4 has

6 each have a spherical characteristic 23, 24. The reverse polarity connection of the two microphone capsules 4, 6 results in the eight characteristic 22 shown in FIG. 4 from the two spherical characteristics 23, 24 when the two microphone capsules 4, 6 are on one level. By the generated by the two microphone capsules 4, 6

Eight characteristic 22 still shows a certain directivity in the direction of driver 14 and front passenger 15, although not as pronounced as in the controllable case of FIG. 2.

5 shows the digital microphone 1 in an emergency in which the two microphone capsules 4, 6 arranged in a horizontal vehicle plane are connected to one another in reverse polarity in the event of an emergency, so that the eight characteristic 22 shown in front of the driver 14 and front passenger 15 results , The eight-way characteristic 22 is a consequence of the two spherical characteristics 23, 24 of the two microphone capsules 4, 6 and an acoustic dipole is created.

An emergency loudspeaker 26 is preferably arranged on the longitudinal axis 25 of the vehicle in the direction of travel 27 in front of the two microphone capsules 4, 6, the arrangement not being mandatory. Other arrangements, for example between driver 14 and passenger 15 or in the second row of seats behind, are conceivable. Due to the eight characteristic 22 due to the symmetrical arrangement of the microphone capsules 4, 6 in the vehicle, not only static noise is compensated from the outset, but also the sound inputs compensated by the emergency call loudspeaker 26 if it is installed on the zero axis of the arrangement of the microphone capsules 4, 6, which in the example in FIG.

Another possibility of arranging the emergency loudspeaker 26 is its arrangement in the defrost air duct of the vehicle, which enables a more homogeneous sound propagation in the vehicle.

LIST OF REFERENCE NUMBERS

Digital microphone

Infotainment system

Automotive audio bus, also known as A ² B or A ² bus

microphone capsule

+ Positive connection

- Negative connection

microphone capsule

+ Positive connection

+ Negative connection

microphone capsule

+ Positive connection

Negative connection

A / D converter

A ² B interface

0 beamforming facility

1 specific directional characteristic

2 beam

3 beam

4 drivers

5 passengers

6 connection

7 connection connection

connection

Online connection unit A ² B-Interface

Eight characteristic emergency omnidirectional characteristic

omnidirectional

Vehicle longitudinal axis emergency loudspeaker

direction of travel

Claims

claims

1. Emergency call system of a motor vehicle with a digital microphone (1), which is connected to a bus master via an automotive audio bus (3) and is controlled by this to provide a predetermined directional characteristic, the digital microphone having at least two microphone capsules (4, 5, 6), the at least two microphone capsules (4, 6) are arranged symmetrically to one another and the digital microphone (1) is arranged in the direction of travel in front of the location of the driver (14) and the location of the passenger (15),

characterized in that

in the event of a failure of the bus master, two microphone capsules (4, 6) are connected to one another in reverse polarity so that a common eight characteristic (22) is generated and the common signals are led out of the digital microphone (1) for further processing.

2. Emergency call system according to claim 1, characterized in that the at least two microphone capsules (4, 6) are arranged in a horizontal plane of the vehicle.

3. Emergency call system according to one of the preceding claims, characterized in that the two microphone capsules (4, 6) are arranged symmetrically to the vehicle longitudinal axis (25).

4. Emergency call system according to one of the preceding claims, characterized in that the bus master is implemented by an infotainment system (2).

5. Emergency call system according to one of the preceding claims, characterized in that the common signals of the two polarity-reversed microphone capsules (4, 6) are fed to an online connection unit (20) for further processing.

6. Emergency call system according to claim 5, characterized in that the online connection unit (20) supplies the common signals to an emergency call center.

7. Emergency call system according to one of the preceding claims, characterized in that the emergency call system has at least one emergency loudspeaker (26).

8. Emergency call system according to claim 7, characterized in that the emergency call speaker (26) is arranged on the axis of symmetry of the two microphone capsules (4, 6) in the direction of travel (27) of the vehicle in front of the microphone capsules.

9. Emergency call system according to claim 7, characterized in that the emergency speaker (26) is arranged in the defrost channel of the vehicle.

10. Emergency system according to claim 7 or 8, characterized in that the

Emergency speaker (26) is arranged on the instrument panel in the center position.

11. Emergency system according to claim 7 or 8, characterized in that the

Emergency speaker (26) is arranged behind the driver (14) and front passenger (15).