WO2020127408A1

WO2020127408A1 - Protective cap for a microphone which can be arranged on the exterior of a vehicle, corresponding microphone, sensor system, and vehicle

Info

Publication number: WO2020127408A1
Application number: PCT/EP2019/085830
Authority: WO
Inventors: Bernd Kernebeck; Danilo Hollosi
Original assignee: Zf Friedrichshafen Ag; Fraunhofer Gesellschaft
Priority date: 2018-12-21
Filing date: 2019-12-18
Publication date: 2020-06-25
Also published as: DE102018222768B3

Abstract

The invention relates to a protective cap (10) for a microphone (20) which can be arranged on the exterior (2) of a vehicle (1) for protecting a microphone membrane (21) against influences emanating from road traffic. The protective cap is designed as an acoustic lens (11) for conducting, bundling, and/or suppressing sound waves. The invention additionally relates to a microphone (20) for a vehicle (1) for detecting traffic noises, wherein the microphone (20) is arranged on the exterior (2) of the vehicle (1) when used and comprises a protective cap (10) according to the invention. The invention additionally relates to a sensor system (30) and to a vehicle (1) comprising multiple sensor systems (30) according to the invention.

Description

PROTECTIVE CAP FOR AN OUTSIDE OF A VEHICLE

ARRANGeable MICROPHONE AND CORRESPONDING MICROPHONE,

SENSOR SYSTEM AND VEHICLE

The invention relates to a protective cap according to claim 1 for a microphone that can be arranged on an outside of a vehicle. Furthermore, the inven tion relates to a microphone according to claim 3 for a vehicle comprising a protective cap according to the invention. In addition, the invention relates to the sensor system according to claim 9 comprising an arrangement of several microphones according to the invention. Furthermore, the invention relates to a vehicle according to claim 1 1 comprising a plurality of sensor systems according to the invention.

Protective caps for microphones in the field of studio recordings, live recordings, theater and concerts are generally known from the prior art. For example, DE1953512 A1 discloses a microphone with a protective cap.

Speakers with acoustic lenses for adjustable sound distribution are also known from the prior art.

Acoustic sensor arrangements for the detection of external noises outside the vehicle are also known from the prior art. For example, DE 10 2016 006 802 A1 discloses a method and a device for detecting at least one special signal originating from an emergency vehicle.

A challenge in the development of such acoustic sensor arrangements is the protection against external influences such as rain water and wind. However, this protection should at the same time have the lowest possible attenuation of the external acoustic signal.

This is where the invention comes in. The invention has for its object to provide a device for microphones in the automotive field, the microphones protects against mechanical influences such as stone chips or water jets and directs or bundles sound in a targeted manner.

The protective cap according to the invention solves this problem with the features of claim 1. The microphone according to the invention solves this problem with the features of claim 3. The sensor system according to the invention solves this problem with the features of claim 9. The vehicle according to the invention solves this problem with the features of Claim 11.

Further developments and advantageous refinements are specified in the following description, the dependent claims and the figures.

The protective cap according to the invention is constructed for a microphone that can be arranged on an outside of a vehicle. The protective cap is designed to protect a microphone diaphragm against influences from road traffic. The protective cap is also designed as an acoustic lens for guiding, bundling and / or masking sound waves.

The following definitions and further explanations apply to the entire subject matter of the invention.

A vehicle is preferably a road vehicle, preferably a passenger or truck.

A protective cap is a component that is wholly or partially pulled over a microphone to protect the microphone against environmental influences. The protective cap is preferably permeable to sound. The protective cap is made of a metal, for example aluminum, or a plastic. The protective cap can have openings, preferably micro-openings. For example, the protective cap comprises a porous material. The protective cap is preferably produced in an additive process. For example, the protective cap is made in a 3D printing process. The protective cap is designed to offer a scope of protection of at least IPX6K. The degree of protection indicates the suitability of components for various environmental conditions. The protected systems are divided into corresponding protection types, so-called International Protection, abbreviated IP codes. The ISO 20653: 2013 standard for road vehicles - degrees of protection (IP code) - protection against third-party objects, water and contact - electrical equipment describes the status of road vehicles. IPX6K offers protection against strong water jets under increased pressure, specifically for road vehicles. The protective cap is preferably a replaceable protective cap.

The protective cap advantageously comprises a latching device, by means of which the protective cap can be attached to the microphone when in use.

When sound waves propagate, a change of direction occurs at interfaces, which is called sound refraction in analogy to the propagation of light waves. Acoustic lenses use refraction in the same way as optical lenses

Collect or disperse sound waves. The acoustic lens is made of aluminum, for example.

Depending on the geometry of the acoustic lens, sound waves are directed, bundled and / or hidden. This makes it possible, in particular, to bundle the sound waves evenly or to specifically hide defined areas. The geometry of the acoustic lens is advantageously adjustable, for example by means of adjustable side parts of the acoustic lens. This allows sound beam widths to be adapted to the respective environment relatively quickly and easily. This is particularly advantageous when used with a microphone on a vehicle. Alternatively, the acoustic lens can be rotated, pivoted and / or tilted.

In a vehicle environment, there are various all-round disturbing noises that overlay signal noises. With the help of the acoustic lens, by adjusting the sound beam width, it is achieved that, for example, only sound waves from a relatively narrow directional cone excite the microphone membrane to vibrate. Sound waves from the outside of this directional cone are masked out. With that Noise, the source of which is located within the directional cone, can be heard better with less interference. The directional cone can be set, for example, to a front, rear or side area of the vehicle. In particular, the opening of the directional cone is variable.

In a preferred embodiment of the invention, the protective cap can be adjusted, that is to say can be aligned, as a function of data from other environment detection sensors, such as radar, lidar or camera. If, for example, a vehicle camera detects other vehicles standing in the front right area of the own vehicle, this detection is processed by an evaluation device. One result of the processing is that there are noises from stationary vehicles in the front right area. The evaluation device converts this information into a control signal for the acoustic lens. By means of this control signal, the acoustic lens is set such that incoming sound waves are masked out from the front right area of the vehicle. This makes it easier to hear noise from approaching emergency vehicles, for example from the rear of your own vehicle, because the interference from standing vehicles is masked out. This makes it easier to hear follow-up horn signals from emergency vehicles.

The protective cap is advantageously designed to protect the microphone membrane from driving wind, rain water, water jets, snow, ice and / or foreign bodies, in particular stones or insects that hit it. The protective cap thus protects the microphone membrane, in particular, from mechanical influences in road traffic.

The microphone according to the invention is designed for a vehicle to detect traffic noise. When in use, the microphone is located on an outside of the vehicle. The microphone comprises a protective cap according to the invention.

A microphone is a sensor that detects sound waves and converts them into an electrical signal, preferably an electrical voltage. The microphone includes one Sound transducer. The sound transducer is a component that converts sound waves, in particular sound pressure changes, into electrical signals. For example, a transducer is an arrangement of a magnet and an electrical coil. Alternatively, the sound transducer works according to the principle of a condenser microphone, Koh lemikrofone or piezo microphone. The microphone is a wired one, for example a USB microphone, or a wireless microphone, for example a Bluetooth microphone.

A microphone membrane is excited to vibrate by the sound pressure. The movement of the microphone membrane simulates the temporal distribution of the sound pressure. The shape of the microphone membrane, the weight of the microphone membrane, the thickness of the microphone membrane and the material of the microphone membrane influence, among other things, the frequency range, limit sound pressure, intrinsic noise and / or sound character of the microphone. The properties and the resulting influences of the microphone membrane are used in accordance with the invention in order to minimize the noise, for example wind noise, which occurs in a vehicle environment.

The microphone according to the invention is designed for the automotive sector. This means in particular that the microphone is insensitive to temperatures in the range from -50 ° C to + 90 ° C, preferably -40 ° C to + 50 ° C. Furthermore, the microphone is insensitive to vibrations.

The microphone includes attachment means to be attached to the vehicle. This means that the microphone can be retrofitted to existing vehicles as a retrofit solution. Alternatively, the microphone is permanently installed in the vehicle body.

With the protective cap according to the invention, the microphone is protected against influences from road traffic. In particular, the protective cap protects the microphone against wind, rain water, water jets, snow, ice and / or foreign bodies, in particular stones or insects hitting it. In addition, the protective cap bundles incoming sound waves as an acoustic lens and / or hides them. The microphone preferably comprises a housing. The protective cap can be integrated into the housing. The housing provides additional protection for the microphone. The housing advantageously comprises fastening means for fastening to the vehicle. Alternatively, the housing is permanently installed in the vehicle body. The housing is made of a metal, for example aluminum, or a plastic.

In an advantageous embodiment of the invention, the housing comprises ribs. The protective cap can be arranged on the housing by means of the ribs. In particular, the protective cap can be replaced by means of the ribs as a supporting structure, for example in order to be cleaned or checked for correct functioning.

In a further embodiment of the invention, the housing has at least one opening for pressure compensation, in particular for pressure compensation for static pressures. If the microphone is arranged on the outside of the vehicle when in use, the driving wind generated while driving exerts pressure on the microphone. The proportional static pressure is compensated through the opening.

The at least one opening is advantageously constructed as a bandpass filter. In particular, the at least one opening represents a high-pass filter. The high-pass filter particularly preferably allows sound waves to pass through at frequencies greater than 300 Hz.

According to a further aspect of the invention, a first protective membrane is arranged between the protective cap and the microphone membrane. The first protective membrane is a flexible or a rigid membrane. The first protective membrane protects the microphone from environmental influences. The first protective membrane is preferably a microporous membrane made of plastic, preferably made of polytetrafluoroethylene.

According to a further aspect of the invention, the microphone comprises a second protective membrane in the area of openings in the protective cap. The second protective membrane between the protective cap and the microphone membrane is preferred, in particular preferably arranged between the protective cap and the first protective membrane. The material of the second protective membrane is advantageously an acoustically transparent foam. The second protective membrane reduces wind noise and protects against dirt, for example against insects that have penetrated between the protective cap and the first protective membrane.

The sensor system according to the invention comprises an arrangement of several microphones according to the invention. The sensor system is therefore an acoustic sensor. The protective caps of the microphones can be aligned. The protective caps of the microphones are preferably mounted such that they can be rotated, pivoted and / or tilted. This allows the acoustic lenses to be aligned in a targeted manner. Depending on the orientation of the acoustic lenses, a signal-to-noise ratio of at least one of the several microphones is optimized due to the targeted bundling of sound for this one microphone and the sound suppression for the other microphones. In particular, the geometry of the acoustic lenses is rigid. The arrangement is an array. The microphones of the array can be arranged as desired, for example offset from one another, in particular circular, rectangular or linear.

The arrangement preferably comprises four microphones arranged next to one another. Such an arrangement is surprisingly very suitable for Ge noise absorption and relatively easy to obtain.

According to the invention, a vehicle comprises several sensor systems according to the invention. A first sensor system is arranged in a front left area of the vehicle. A second sensor system is arranged in a front right area of the vehicle. A third sensor system is arranged in a rear left area of the vehicle. A fourth sensor system is arranged in a rear right area of the vehicle. This arrangement with four sensor systems enables 360 ° detection of ambient noise. For example, the sensor systems each include four microphones arranged side by side. In this example, for example, useful signals from the front left area of the vehicle are to be searched. In particular, data from other environment detection sensors are merged in order to use the fusion to recognize that the front left area of the vehicle must be searched for acoustic signals. For example, it was recognized with a camera that a truck was driving to the right of the vehicle. The driving noises of the truck are disturbing noises relative to useful signals to be detected from the front area. This noise is to be masked out. For this purpose, the acoustic lenses of the front sensor systems are specifically adjusted. The acoustic lenses of the sensor system, which is arranged in front of the left area of the vehicle, are set such that sound concentration is achieved for the outer left microphone of this sensor system and for the three microphones arranged to the right of the outer left microphone, a sound suppression is achieved becomes. In particular, the acoustic lens of the outer right microphone of this sensor system is set in such a way that the striking sound is masked out. The sensor system, which is arranged in the front right area of the vehicle, is not activated in this example. Without alignment of the acoustic lenses, the signals from the microphones of the sensor system in the front left area have the same signal-to-noise ratio.

With the alignment of the acoustic lenses, the noise component of the outer left microphone of this sensor system is small compared to the three microphones arranged to the right of it, and the useful signal component is comparatively large. This means that a strongly disturbed signal can be switched off.

The invention is exemplified in the following figures. Show it:

1 is a sectional view of an embodiment of a microphone according to the invention with an embodiment of a protective cap according to the invention,

2 shows a front view of the microphone from FIG. 1,

3 shows an exemplary embodiment for using the microphone from FIG. 1,

4 shows an embodiment of a sensor system according to the invention,

5 shows an embodiment of a vehicle with four sensor systems from FIG. 4, Fig. 6a signal-to-noise ratios of the microphones of the front left sensor system from Fig. 5 without alignment of the acoustic lenses and

Fig. 6b signal-to-noise ratios from Fig. 6a with alignment of the acoustic Lin sen.

In the figures, the same reference numerals designate the same or functionally similar parts. For the sake of clarity, only the reference parts relevant to the respective understanding are identified in the individual figures.

1 shows a microphone 20 with a microphone membrane 21. The microphone 20 is integrated in a housing 22. The housing 22 comprises an opening 24. A pressure compensation for static pressures takes place via the opening 24. The opening 24 fulfills the function of a high-pass filter for the microphone 20. Depending on the diameter of the opening 24, length of the opening 24 and / or position of the opening 24 in the housing 22, in particular sound waves with frequencies less than 300 Hz are filtered.

The microphone 20 includes a protective cap 10. The protective cap 10 is placed over the microphone 20. The protective cap 10 protects the microphone 20, in particular the microphone membrane 21, from mechanical influences which can occur in road traffic. Examples of such mechanical influences are stone chips or water spray.

The protective cap 10 is designed as an acoustic lens 11. The acoustic lens 1 1 bundles and / or hides adjustable areas of incoming sound.

The protective cap 10 and thus also the acoustic lens 11 is exchangeably attached to the housing 22 by means of a structure of ribs 23.

Between the protective cap 10 and the microphone membrane 21, a first protective membrane 25 is arranged. The first protective membrane 25 protects the microphone 20, in particular the microphone membrane 21, from environmental influences, for example wind and / or water. FIG. 2 shows the housing 22. The housing 22 is a component that can be attached to existing vehicles as a retrofit solution or is integrated in new vehicles. The microphone 20 and the acoustic lens 11 are integrated into the housing 22.

FIG. 3 shows the use of the microphone 20 with a protective cap 10. The microphone 20 is arranged on an outside 2 of a vehicle 1. The vehicle 1 is a car, for example, but can also be a commercial vehicle, in particular a truck 3, or other road vehicle. The microphone 20 is arranged on a roof of the vehicle 1. Alternatively, the microphone 20 is arranged in the area of a bumper or on a side area of the vehicle.

In the sensor system 30 of FIG. 4, four microphones 20 are arranged in a row, namely from left to right, an outer left microphone I, a middle left microphone ml, a middle right microphone mr and an outer right microphone r.

5 shows a vehicle 1, for example a car. The vehicle 1 comprises four sensor systems 30, namely a sensor system 30 arranged in front left, front right, rear left and rear right in relation to vehicle 1. A truck drives to the right of the vehicle. Driving noises of the truck are interference signals S in relation to a useful signal N, which is to be detected from a front left area of the vehicle. The acoustic lenses 1 1 of the microphones I, ml, mr and r are aligned in such a way that the sound concentration of the microphone I is optimal. The signal-to-noise ratio SNR of the microphone I is thus optimal relative to the microphones ml, mr and r.

The effect of the alignment of the acoustic lenses 11 on the signal-to-noise ratio SNR is shown in FIGS. 6a, without alignment, and 6b, with alignment. With the alignment of the acoustic lenses 1 1, the useful signal N in the microphone I is improved. Reference sign

1 vehicle

2 outside

3 trucks

10 protective cap

11 acoustic lens

20 microphone

21 microphone membrane

22 housing

23 rib

24 opening

25 first protective membrane

26 second protective membrane

30 sensor system

I outer left microphone

ml Middle left microphone

mr middle right microphone

r outer right microphone

N useful signal

S Interference signal

SNR signal-to-noise ratio

Claims

1. Protective cap (10) for an on an outside (2) of a vehicle (1) arrangeable microphone (20) for protecting a microphone membrane (21) against the effects of road traffic, designed as an acoustic lens (1 1) Conduct, bundle and / or block out sound waves.

2. Protective cap (10) according to claim 1, designed to protect the microphone membrane (21) from wind, rain water, water jets, snow, ice and / or foreign bodies, in particular striking stones or insects.

3. microphone (20) for a vehicle (1) for detecting traffic noise, the microphone (20) being arranged when used on an outside (2) of the vehicle (1), comprising a protective cap (10) according to claim 1 or 2nd

4. Microphone (20) according to claim 3 comprising a housing (22), wherein the protective cap (10) in the housing (22) can be integrated.

5. Microphone (20) according to claim 4, wherein the housing (22) comprises ribs (23) and the protective cap (10) can be arranged by means of the ribs (23) on the housing (22).

6. Microphone (20) according to claim 4 or 5, wherein the housing (22) has at least one opening (24) for pressure equalization.

7. Microphone (20) according to any one of claims 3 to 6, wherein a first protective membrane (25) is arranged between the protective cap (10) and the microphone membrane (21).

8. Microphone (20) according to any one of claims 3 to 7, wherein the microphone in the region of openings of the protective cap (10) comprises a second protective membrane (26).

9. Sensor system (30) comprising an arrangement of a plurality of microphones (20) according to one of claims 3 to 8, wherein protective caps (10) of the microphones (20) can be aligned to a signal-to-noise ratio of at least one of the plurality Mic to optimize the rofone (20) relative to at least one other of the plurality of microphones.

10. Sensor system (30) according to claim 9, wherein the arrangement comprises four microphones (20) arranged side by side.

1 1. Vehicle (1) comprising a plurality of sensor systems (30) according to claim 9 or 10, wherein a first sensor system (30) in a front left area of the vehicle (1), a second sensor system (30) in a front right area of the vehicle (1), a third sensor system (30) in a rear left area of the vehicle (1) and a fourth sensor system (30) in a rear right area of the vehicle (1) is arranged.