WO2018065140A1

WO2018065140A1 - Ultrasonic sensor, driver assistance device, motor vehicle and method for operating an ultrasonic sensor

Info

Publication number: WO2018065140A1
Application number: PCT/EP2017/069414
Authority: WO
Inventors: Serge Tchouaffe
Original assignee: Valeo Schalter Und Sensoren Gmbh
Priority date: 2016-10-07
Filing date: 2017-08-01
Publication date: 2018-04-12
Also published as: DE102016119099A1; DE102016119099B4

Abstract

The invention relates to an ultrasonic sensor (5) for a motor vehicle (1), having a membrane (10), wherein the membrane (10) is configured to emit ultrasound waves (17). Furthermore, the ultrasonic sensor (5) has a transducer device (11), wherein the transducer device (11) is configured to excite the membrane (10) to emit ultrasound waves (17). Moreover, the ultrasonic sensor (5) comprises a lens device (15), wherein the membrane (10) is arranged between the transducer device (11) and the lens device (15) in such a way that the ultrasound waves (17) that are emitted by the membrane (10) pass through the lens device (15). The shape of the lens device (15) can be changed and a directional characteristic of the ultrasonic sensor (5) is set depending on the shape of the lens device (15).

Description

Ultrasonic sensor, driver assistance device, motor vehicle and method for

Operating an ultrasonic sensor

The present invention relates to an ultrasonic sensor for a motor vehicle with a membrane and a transducer device, wherein the transducer device is adapted to excite the membrane for emitting the ultrasonic waves, and a

Lens device, wherein the membrane between the transducer device and the lens device is arranged such that the ultrasonic waves emitted by the membrane pass through the lens device. In addition, the present concerns

Invention, a driver assistance system with at least one such ultrasonic sensor. The invention also relates to a motor vehicle with such

Driver assistance system. Finally, the present invention relates to a method for operating an ultrasonic sensor for a motor vehicle.

The interest is directed in the present case in particular to ultrasonic sensors for

Motor vehicles. Such ultrasonic sensors are already known from the prior art and can, for example, in the front and in the rear of a

Motor vehicle be installed. For example, the ultrasonic sensors may be arranged on the bumpers of the motor vehicle. The ultrasonic sensors may be associated, for example, with a driver assistance system of the motor vehicle and provide information about the surroundings of the motor vehicle. For example, a distance between the motor vehicle and an object or an obstacle in the surroundings of the motor vehicle can be determined with the ultrasonic sensors. The driver assistance system can serve, for example, to assist the driver when parking the motor vehicle.

The ultrasonic sensors usually have a membrane. The membrane can be excited with a corresponding transducer means to mechanical vibrations. In addition, a mechanical vibration of the membrane can be detected with the transducer device. The ultrasonic sensors are operated in particular in three successive operating phases. During a transmission phase, the membrane of the ultrasonic sensor is excited to mechanical vibrations by means of the transducer device. This has the consequence that with the ultrasonic sensor a

Ultrasonic signal or ultrasonic waves are emitted. In a subsequent decay phase excites the membrane and the membrane swings out. In a reception phase following the decay phase For example, the ultrasound signal reflected from the object in the environment can strike the membrane again and cause it to vibrate mechanically. These

mechanical vibrations can be detected with the piezoelectric element and output in the form of an electrical signal. Based on the transit time between the emission of the ultrasound signal and the reception of the reflected ultrasound signal

or the echo, the distance between the motor vehicle and the object can be determined.

The disadvantage of such a structure is that a directional characteristic of the ultrasonic sensor is determined solely by the nature of the membrane. Depending on how the membrane is designed, the ultrasonic sensor is suitable for

Detecting objects near the floor area, such as a curb, or rather detecting objects at the height of the built-in ultrasonic sensor, such as road users.

In order to optimize the directional characteristic of an ultrasonic sensor, the document DE 10 201 1 121 095 A1 proposes an arrangement with a vehicle component and with an ultrasonic sensor arranged on the vehicle component. Of the

The ultrasonic sensor has a diaphragm configured to emit and receive ultrasonic waves, and a sensor housing in which the

Ultrasonic sensor is arranged at least partially and via which the

Ultrasonic sensor is connected to the vehicle component. At least one component of the arrangement is at least partially formed of a sound-absorbing material. The vehicle component is in the region of the membrane of the

formed sound-absorbing material, so that an acoustic lens for

Ultrasonic waves is formed.

In addition, an ultrasonic probe is described in the article "Mechanical Focusing of Ultrasonic Fields" by Andreas Mück, Mark Achtenberg, Werner Kraus, Norman Moritz and Christian Probst The ultrasound probe has a piezo oscillator as a transducer device and an acoustic lens for focusing the ultrasound field.

It is an object of the present invention to provide a solution, such as a

Ultrasonic sensor for a motor vehicle of the type mentioned can be operated more efficiently. This object is achieved by an ultrasonic sensor by a

Driver assistance system, solved by a motor vehicle and by a method having the features according to the respective independent claims. advantageous

Embodiments of the invention are the subject of the dependent claims, the

Description and figures.

An inventive ultrasonic sensor comprises a membrane, which is adapted to emit ultrasonic waves. Furthermore, the ultrasonic sensor comprises a transducer device, wherein the transducer device is adapted to the

Stimulate membrane for emitting the ultrasonic waves. Furthermore, the ultrasonic sensor comprises a lens device. The membrane is between the

Transducer device and the lens device arranged such that the emitted from the membrane ultrasonic waves pass through the lens device. The

The invention is characterized in that a shape of the lens device is variable and depending on the shape of the lens device, a directional characteristic of the ultrasonic sensor is set.

The ultrasonic sensor can be arranged on the motor vehicle. With the

Ultrasonic sensor can be detected an object in an environment of the motor vehicle. Using the ultrasonic sensor, in particular the distance between the

Motor vehicle and the object to be determined. The ultrasonic sensor has a membrane which may be made of aluminum. Furthermore, the ultrasonic sensor has a transducer device, with which the membrane can be excited to mechanical vibrations. In this case, the transducer device can be mechanically connected to the membrane. The ultrasonic sensor can be arranged in a corresponding opening of a trim part, in particular of a bumper, of the motor vehicle. The ultrasonic sensor can also be used for concealed arrangement behind the

Be fairing designed.

In the present case, the ultrasonic sensor has a lens device whose shape can be changed. In other words, a structure or extension of the lens device can be adjusted. Depending on the shape of the lens device, a directional characteristic of the ultrasonic sensor can be adjusted. The ultrasound waves emitted by the membrane are preferably directed towards the lens device. Depending on which shape has the lens device, a

Main propagation direction of the ultrasonic waves are changed or adjusted. With main propagation direction of the ultrasonic waves is meant in particular a direction in which the ultrasonic waves propagate with higher intensity or the direction in which the ultrasonic waves have a higher intensity. In other words, the lens device may be configured to focus the ultrasonic waves. This has the advantage that the directional characteristic of the

Ultrasonic sensor not fixed, but is variably adjustable. As a result, the ultrasonic sensor is versatile. This enables efficient operation of the ultrasonic sensor.

The lens device can be designed, for example, as a lens, in particular as an ultrasound lens or acoustic lens. In particular, the lens device or lens has a predetermined lens shape, in particular a biconvex or a

concave convex or a plano-convex shape, in particular basic shape, on. The lens device may preferably have a round or oval shape of the outer contour. In other words, the lens device may be formed on an outer circumference round or oval.

One embodiment provides that the ultrasonic sensor comprises an actuator, which is coupled to the lens device, in particular mechanically coupled, and is adapted to change the shape of the lens device such that the lens device is stretched or compressed perpendicular to a main propagation direction of the ultrasonic waves , In other words, the actuator may be configured to exert a force on the lens device so that the lens device is stretched or compressed perpendicular to the main propagation direction of the ultrasonic waves. For this purpose, the actuator can be coupled or connected to a control device which is set up to control the actuator. The control device can provide an electrical signal, for example a time-variable electrical voltage, for driving the actuator. The control device can be formed for example by a control unit of the motor vehicle (ECU - Electronic Control Unit) or by the electronics of the ultrasonic sensor itself.

When stretching or upsetting the lens device, a basic shape or original shape of the lens device can be maintained and an extension of the lens device perpendicular to the main propagation direction of the ultrasonic waves can be changed. When the lens device is stretched, a diameter of the lens device can be increased in the original shape as compared with the diameter of the lens device. By stretching or expanding the lens device perpendicular to the main propagation direction, an expansion of the lens device in the Main propagation direction of ultrasonic waves smaller. In other words, by stretching the lens device, a thickness of the lens device can be reduced. When the lens device is compressed or compressed, a diameter of the lens device can be reduced in size as compared with the diameter of the lens device. By upsetting the lens perpendicular to the main propagation direction, in particular, an expansion of the lens device in the main propagation direction of the ultrasonic waves becomes larger. In other words, by upsetting the lens device, a thickness of the lens device can be increased. A stretching of the lens device leads in particular to the fact that the

Ultrasonic waves are emitted homogeneously or evenly. As a result, in particular, the detection of objects in the vicinity of the floor area, such as

For example, a curb, be improved. An upsetting of

Lens device leads in particular to the fact that the ultrasonic waves are focused towards the center of the lens device. As a result, in particular the detection of objects at the level of the built-in ultrasonic sensor, such as

Road users.

According to an advantageous development, it is provided that the actuator has a piezoelectric element, wherein the piezoelectric element is arranged on an outer periphery of the lens device. In other words, the piezoelectric element may be disposed on an edge of the lens device. In order that the shape of the lens device may be changed, the lens device may be fixed to a predetermined area on the outer circumference of the lens device, and the piezoelectric element may be disposed opposite to the predetermined region on the outer circumference. Particularly preferably, the actuator has two

piezoelectric elements disposed on the outer periphery of the lens device. In particular, the two piezoelectric elements are on the

Outer circumference arranged opposite each other. By the actuator, there is the advantage that the shape of the lens device can be adjusted in a particularly simple and reliable manner.

Advantageously, the lens device is formed of an elastic material. Particularly preferably, the lens device can have a lens wall, which encloses a lens chamber. The lens wall may be formed of an elastic material. In the lens chamber, a lens fluid may be included.

Alternatively, the lens device may be formed of an electroactive polymer. Electroactive polymers are in particular polymers which are produced by the application of a electrical voltage change shape. Additionally or alternatively, the

Lens device may be formed of a transparent or partially transparent material.

An advantageous development provides that the ultrasonic sensor has a horn, wherein the lens device is received in the horn, wherein the horn is arranged on the membrane. The horn may be configured to hold or store the lens device. In other words, the horn may be configured to enclose the lens device. In ultrasonic sensors, the horn is preferably used to improve a radiation of the ultrasonic waves in air. Since the lens device is located in the horn or held by the horn, the horn comes one

Double function benefit. On the one hand, the radiation of the ultrasonic waves in air can be improved and, on the other hand, the lens device can be kept particularly reliable. This results in the advantage that no additional element is needed to fix the lens device.

An inventive driver assistance system for a motor vehicle comprises at least one ultrasonic sensor according to the invention. It can also be provided that the driver assistance system has a plurality of ultrasonic sensors. These ultrasonic sensors can be distributed, for example, arranged on the motor vehicle. The driver assistance system can be designed in particular as a so-called parking aid.

A motor vehicle according to the invention comprises an inventive

Driver assistance system. The motor vehicle is designed in particular as a passenger car.

An inventive method is used to operate an ultrasonic sensor for a motor vehicle. In this case, ultrasonic waves are emitted by means of a membrane. For emitting the ultrasonic waves, the membrane is excited by means of a transducer device. Furthermore, the ultrasound sensor has a lens device, wherein the membrane is arranged between the transducer device and the lens device such that the ultrasound waves emitted by the membrane pass through the lens device. In other words, those emitted by the membrane

Ultrasonic waves directed to the lens device. In the method, a shape of the lens device is changed while adjusting a directivity of the ultrasonic sensor depending on the shape of the lens device. In other words, in the operation of the ultrasonic sensor depending on the shape of the set Lens device, the directional characteristic of the ultrasonic sensor can be changed. By a physical adaptation of the lens device, a shape or geometry of the lens device can be changed.

The presented with respect to the ultrasonic sensor according to the invention preferred embodiments and their advantages apply correspondingly for the driver assistance system according to the invention, the motor vehicle according to the invention and the

inventive method.

Further features of the invention will become apparent from the claims, the figures and the description of the figures. The features and feature combinations mentioned above in the description, as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures, are not only in the respectively indicated combination but also in others

Combinations or alone, without departing from the scope of the invention. Thus, embodiments of the invention are to be regarded as encompassed and disclosed, which are not explicitly shown and explained in the figures, but which emerge and can be produced by separated combinations of features from the embodiments explained. Embodiments and combinations of features are also to be regarded as disclosed, which thus do not have all the features of an originally formulated independent claim.

The invention will now be described with reference to preferred embodiments and with reference to the accompanying drawings.

Showing:

1 shows a motor vehicle according to an embodiment of the present invention, which has a driver assistance system with a plurality of

Having ultrasonic sensors; and

2 shows an ultrasonic sensor according to an embodiment of the present invention

Invention in a sectional side view.

In the figures, the same and functionally identical elements are the same

Provided with reference numerals. Fig. 1 shows a motor vehicle 1 according to an embodiment of the present invention in a plan view. The motor vehicle 1 is in the present case as

Passenger cars trained. The motor vehicle 1 comprises a

Driver assistance system 2. The driver assistance system 2 in turn comprises a

Ultrasonic sensor device 3, which has a control device 4 and at least one ultrasonic sensor 5. The control device 4 may be formed for example by an electronic control unit (ECU - Electronic Control Unit) of the motor vehicle 1.

The ultrasonic sensor device 3 according to FIG. 1 comprises eight ultrasonic sensors 5. Four ultrasonic sensors 5 are arranged in a front region 6 of the motor vehicle 1 and four ultrasonic sensors 5 in a rear region 7 of the motor vehicle 1. The ultrasonic sensors 5 are designed to detect an object 8 in an environment 9 of the motor vehicle 1. In addition, the ultrasonic sensors 5 are used to determine a distance between the object 8 and the motor vehicle 1. The ultrasonic sensors 5 are connected to the control device 4 for data transmission. Corresponding data lines are not shown here for the sake of clarity.

Fig. 2 shows an ultrasonic sensor 5 according to an embodiment of the present invention in a sectional side view. The ultrasonic sensor 5 comprises a membrane 10. The membrane 10 may be made of a metal, in particular aluminum, for example. In addition, the ultrasonic sensor 5 comprises a

Converter device 1 1. The converter device 1 1 is formed as a piezoelectric element. The piezoelectric element is in particular made of a piezoelectric material. In this case, the piezoelectric element is connected to the membrane 10, in particular to a rear side 12 of the membrane 10.

The converter device 1 1 can also be coupled to the control device 4. The control device 4 can provide an electrical signal, for example a time-variable electrical voltage, for driving the converter device 1 1. For this purpose, the control device 4 may have a pulse generator 13.

On a front side 14 of the membrane 10, opposite the back 12 of the membrane, a lens device 15 or lens is further arranged. The lens device 15 has a plano-concave shape. The lens device 15 is received in a horn 16, which is arranged on the front side 14 of the membrane 10. The horn 16 is used on the one hand for mounting the lens device 15 and on the other hand for improving the emission of ultrasonic waves 17, which are emitted from the membrane 10. The diaphragm 10, the transducer device 1 1, the pulse generator 13, the lens device 15 and the horn 16 are received or arranged in a housing 18.

With the aid of the lens device 15, a directional characteristic of the ultrasonic sensor 5 can be adjusted. For adjusting the directivity, a form of

Lens device 15 are changed. In changing the shape of the lens device 15, the lens device 15 can be stretched or compressed perpendicular to a main propagation direction 19 of the ultrasonic waves 17. When changing the shape, the lens device 15 is compressed or pulled apart perpendicular to the main propagation direction 19. For this purpose, the lens device 15 is preferably formed from an elastic material.

Furthermore, the shape of the lens device 15 can be adjusted or changed by means of an actuator (not shown in FIG. 2). The actuator is adapted to exert a force on the lens device 15, in particular a tensile force or a

Compressive force. The actuator can be controlled by a further control device (not shown in FIG. 2). For example, the actuator may comprise a piezoelectric element formed of a piezoelectric material. By the

Actuation of the piezoelectric element, the lens device 15 can extend or contract perpendicular to the main propagation direction 19.

The piezoelectric element may be on an outer periphery or edge of

Lens device 15 may be arranged. In order that the shape of the lens device 15 can be changed, the lens device 15 at a predetermined range on

Outer periphery of the lens device 15 may be fixed and the piezoelectric element may be disposed opposite to the predetermined region on the outer periphery. Particularly preferably, the actuator has two piezoelectric elements, which are arranged on the outer periphery of the lens device 15. In particular, the two piezoelectric elements are opposed to each other on the outer circumference

arranged. Preferably, the two piezoelectric elements are so on the

Outer circumference arranged opposite each other, that the lens device 15 can be stretched or compressed perpendicular to the main propagation direction 19.

Instead of providing an actuator, the lens device 15 may be formed of an electroactive polymer. In this case, the lens device 15 directly with the other Be coupled control means, which outputs an electrical signal to the lens device 15 to change the shape of the lens device 15. The others

Control device may be formed by the electronics of the ultrasonic sensor 5 itself. The further control device can likewise be accommodated in the housing 18 of the ultrasonic sensor 5.

If the actuator exerts a pulling force on the lens device 15, then the

Lens device 15 is stretched perpendicular to the main propagation direction 19. If the actuator exerts a pressure force on the lens device 15, then the lens device 15 is compressed or compressed perpendicular to the main propagation direction 19. When stretching or compressing the lens device 15, a basic shape or

maintain original shape of the lens device 15 and an extension of the lens device 15 perpendicular to the main propagation direction 19 of the

Ultrasonic waves 17 change. If the lens device 15 is stretched, then

For example, a diameter of the lens device 15 in comparison to the

Diameter of the lens device 15 are increased in the original form. By stretching or expanding the lens device 15 perpendicular to

In the main propagation direction 19, the extension of the lens device 15 in the main propagation direction 19 of the ultrasonic waves becomes smaller. In other words, by stretching the lens device 15, a thickness of the lens device 15 in the direction of the main propagation direction 19 can be reduced. If the lens device 15 is compressed or compressed, for example, the diameter of the lens device 15 can be reduced in size compared to the diameter of the lens device 15 in its original form. By upsetting the lens device 15 perpendicular to the main propagation direction 19, the extension of the lens device 15 in the main propagation direction 19 of the ultrasonic waves becomes larger. In other words, by upsetting the lens device 15, a thickness of the lens device 15 can be increased or increased. A stretching of the lens device leads in particular to the fact that the ultrasonic waves 17 are emitted homogeneously or evenly. In particular, upsetting of the lens device 15 causes the ultrasonic waves 17 to be focused toward a center of the lens device 15.

Overall, an ultrasonic sensor with built-lens device is described by the invention.

Claims

claims

1 . Ultrasonic sensor (5) for a motor vehicle (1) comprising:

a membrane (10), wherein the membrane (10) is adapted to

To emit ultrasonic waves (17);

- A transducer means (1 1), wherein the transducer means (1 1) is adapted to excite the membrane (10) for emitting the ultrasonic waves (17); and

- A lens device (15), wherein the membrane (10) between the

Transducer device (1 1) and the lens device (15) is arranged such that the of the membrane (10) emitted ultrasonic waves (17) the

Pass lens device (15);

characterized in that

- A form of the lens device (15) is variable and

- As a function of the shape of the lens device (15) a directional characteristic of the ultrasonic sensor (5) is set.

2. Ultrasonic sensor (5) according to claim 1,

characterized in that

the ultrasonic sensor (5) has an actuator, wherein the actuator with the

Lens device (15) is coupled and adapted to the shape of the

To change the lens device (15) such that the lens device (15) is stretched or compressed perpendicular to a Hauptausbreitungsrichtung (19) of the ultrasonic waves.

3. ultrasonic sensor (5) according to claim 2,

characterized in that

the actuator has a piezoelectric element, wherein the piezoelectric element is arranged on an outer periphery of the lens device (15).

4. Ultrasonic sensor (5) according to one of the preceding claims,

characterized in that

the lens device (15) has a biconvex or a concave-convex or a plano-convex shape.

5. ultrasonic sensor (5) according to any preceding claim, characterized in that

the lens device (15) is formed of an elastic material.

6. ultrasonic sensor (5) according to any one of claims 1 or 2 or 4 or 5,

characterized in that

the lens device (15) is formed from an electroactive polymer.

7. Ultrasonic sensor (5) according to one of the preceding claims,

characterized in that

the transducer means (1 1) comprises a piezoelectric element.

8. Ultrasonic sensor (5) according to one of the preceding claims,

characterized in that

the ultrasonic sensor (15) has a horn (16), the lens device (15) being accommodated in the horn (16), the horn (16) being arranged on the membrane (10).

9. driver assistance system (2) with at least one ultrasonic sensor (5) according to one of the anticipated claims.

10. Motor vehicle (1) with a driver assistance system (2) according to claim 9.

1 1. Method for operating an ultrasonic sensor (5) comprising the steps:

- emitting ultrasonic waves (17) by means of a membrane (10);

- exciting the membrane (10) for emitting the ultrasonic waves (17) by means of a transducer device (1 1);

marked by

- Changing a shape of a lens device (15) of the ultrasonic sensor (5), wherein the membrane (10) between the transducer means (1 1) and the lens device (15) is arranged such that of the membrane (10) emitted

Ultrasonic waves (17) pass through the lens device (15) and

- Setting a directional characteristic of the ultrasonic sensor (5) in dependence on the shape of the lens device (15).