DE102021211597A1 - Ultrasonic sensors for unsuitable installation positions - Google Patents

Abstract

Disclosed is a method for controlling at least one ultrasonic sensor array for emitting sound echoes into a detection area, wherein the ultrasonic sensor array has at least two transducer elements spaced apart from one another in the vertical direction and/or in the horizontal direction, the transducer elements being driven out of phase by a control device electrically connected to the transducer elements, to tilt a main axis of the emitted sound echoes with respect to a surface normal of the ultrasonic sensor array. Furthermore, a method for controlling at least one ultrasonic sensor array for receiving sound echoes reflected from a detection area, a control device, a computer program and a machine-readable storage medium are disclosed.

Description

The invention relates to a method for controlling at least one ultrasonic sensor array for emitting sound echoes in a detection area. Furthermore, the invention relates to a method for controlling at least one ultrasonic sensor array for receiving sound echoes reflected from a detection area, a control device, a computer program and a machine-readable storage medium.

State of the art

Due to their vertical radiation behavior, ultrasonic sensors for detecting the vehicle surroundings cannot be integrated into a bumper with any angle of inclination, but must also have a corresponding angle of inclination for a specific installation height, taking into account the tolerances. The main lobe of ultrasonic sensors is typically within a solid angle range of +-30° in relation to the membrane normal or surface normal. In particular, depending on the installation height relative to a subsurface, the angle of inclination of the ultrasonic sensor must be adjusted in such a way that ground echo amplitudes are reduced and objects that are low in height and cannot be driven over can continue to be detected by the ultrasonic sensor. In this case, negative angles of attack are particularly problematic, since they lead to increased ground echo amplitudes and thus to a reduction in the sensitivity of the ultrasonic sensor.

The integration of the ultrasonic sensors is still linked to various design requirements. In particular, ultrasonic sensors should be arranged flush and unobtrusively so as not to attract attention. However, such an integration of ultrasonic sensors is only possible to a limited extent, depending on the vehicle design, and often requires the use of mechanical funnels in order to ensure the prescribed angle of inclination. Funnels of this type involve increased assembly costs and disadvantages in terms of optics.

In the DE 10 2018 100 567 A1 a method for determining a position of an object in an area surrounding a motor vehicle is disclosed.

The US 2020/0196527 A1 describes a system with a radar-based beamforming sensor configured to collect sensor data related to a mowing swath in an agricultural area.

Disclosure of Invention

The object on which the invention is based can be seen as proposing a method for operating ultrasonic sensors, by means of which the use of funnels is avoided even in the case of unfavorable installation positions.

This object is solved by means of the respective subject matter of the independent claims. Advantageous configurations of the invention are the subject matter of the dependent subclaims.

According to one aspect of the invention, a method for controlling at least one ultrasonic sensor array for emitting acoustic echoes into a detection area is provided. The ultrasonic sensor array has at least two transducer elements that are spaced apart from one another in the vertical direction and/or in the horizontal direction, with the transducer elements being controlled out of phase by a control device electrically connected to the transducer elements in order to tilt a main axis of the emitted sound echoes relative to a surface normal of the ultrasonic sensor array.

The respective converter elements are designed as partial sensors of the ultrasonic sensor array and can be controlled and evaluated independently of one another by the control device. In particular, the sound waves generated by the transducer elements can interfere with one another, as a result of which the main axis of the emitted sound echoes is tilted or deflected with respect to the surface normal.

In particular, the main axis of the vertical sound emission can be tilted with respect to the main axis of the sensor membrane by driving the transducer elements with a phase offset, for example between the vertically offset rows of elements.

The surface normal is preferably perpendicular to a housing or an outer surface of the ultrasonic sensor array aligned in the emission direction. The transducer elements, which are excited by membrane vibrations and/or cylinder vibrations to generate and receive sound waves, are preferably arranged on a common plane, on the basis of which the surface normal is defined.

With the method, the mechanical sound field correction by means of a funnel can be replaced by a so-called digital beamforming of the directional characteristic in a transmission mode or transmission state and in a reception mode or reception state. The direction of the vertical sound keule is set via a control unit designed as a dedicated control logic.

According to a further aspect of the invention, a control unit is provided, the control unit being set up to carry out the method. The control unit can be, for example, a vehicle-side control unit, a vehicle-external control unit or a vehicle-external server unit, such as a cloud system. The control unit can preferably receive and process measurement data from the at least one measurement antenna and/or measurement data from sensors in the at least one mobile unit.

In addition, according to one aspect of the invention, a computer program is provided which includes instructions which, when the computer program is executed by a computer or a control unit, cause the latter to execute the method according to the invention. According to a further aspect of the invention, a machine-readable storage medium is provided on which the computer program according to the invention is stored.

The control unit and the at least one ultrasonic sensor array can be arranged in a mobile unit which, according to the BASt standard, can be operated in an assisted, partially automated, highly automated and/or fully automated or driverless manner. For example, the mobile unit can be designed as a vehicle, a robot, a drone, a watercraft, a rail vehicle, a robotaxi, an industrial robot, a commercial vehicle, a bus, an airplane, a helicopter and the like

In a further exemplary embodiment, a phase offset of the at least two transducer elements of the ultrasonic sensor array is adjusted and/or varied as a function of an installation height of the ultrasonic sensor array above a substrate.

Typically, ultrasonic sensors are installed between 30 cm and 70 cm installation height. With an installation height of 30 cm, the normal to the surface should be at an angle of approx. 10° to the ground in order to reduce ground echoes due to the lower installation height. With an installation height greater than 48 cm, angles of attack of approx. 2° are preferred in order to avoid detection losses of low but crash-relevant objects, such as low walls. Between the installation height of 30 cm and 48 cm there is a linear relationship between the installation height and the preferred angle of attack between 10° and 2°.

The control device can implement these different angles of attack according to the setting of the phase offset between the respective transducer elements by tilting the main axis of the emitted sound echoes with respect to a surface normal of the ultrasonic sensor array. This measure allows the ultrasonic sensor array to be dynamically adapted to different heights relative to the ground, for example in vehicles with air suspension.

In addition, the ultrasonic sensor array can be operated reliably in different vehicles at different installation positions or independently of the installation position, since the installation height can be automatically compensated by the method.

According to a further aspect of the invention, a method for controlling at least one ultrasonic sensor array for receiving sound echoes reflected from a detection area is provided. This control of the ultrasonic sensor array can also be done by a control unit. Different control devices or one control device can be used for the transmission mode and for the reception mode.

The ultrasonic sensor array has at least two transducer elements spaced apart from one another in the vertical direction and/or in the horizontal direction. The transducer elements are switched into a reception state with a phase offset relative to a transmission state. Due to the phase-shifted "reading" of the transducer elements by the control unit, sound echoes from defined solid angles or solid angle ranges can be received in a targeted manner. This measure allows the at least one ultrasonic sensor array to be operated as a directional antenna for sound echoes, as a result of which sound echoes reflected on the subsoil can also be suppressed when the measurement data is received.

This directional characteristic in the reception mode of the ultrasonic sensor array can be the same as a directional characteristic in the transmission mode or can deviate from the directional characteristic in the transmission mode.

The reception sensitivity can be set independently of the sound radiation for defined solid angle ranges. For this purpose, the received signals are added with a phase delay.

In particular, such a phase-delayed addition of reception signals for setting the reception sensitivity can take place independently of the sound radiation in the transmission mode.

According to one embodiment, the converter elements are operated in a reception state with a phase offset in such a way that reflected sound waves are received from at least one solid angle range and converted to measurement data. As a result, the directional characteristic during reception can be adjusted by a phase offset that is different from the directional characteristic during transmission. Any number of directional characteristics and in particular solid angles can be received and evaluated in parallel (i.e. simultaneously) in reception mode. However, this digital beamforming requires a high computing effort. An evaluation of a few solid angles or solid angle ranges coupled to a driving situation can reduce the computing effort and enable a targeted evaluation adapted to the driving situation.

According to a further exemplary embodiment, a driving situation is determined. The at least one solid angle or at least one solid angle range is preferably set based on the determined driving situation. This measure allows an evaluation of different directional characteristics to be linked to the driving situation.

To determine the driving situation, measurement data from at least one sensor can be received and evaluated by the control unit. For example, the driving situation can be determined based on measurement data from a GNSS sensor, a LIDAR sensor, a speed sensor, a camera sensor and the like.

In static driving situations, such as when starting the vehicle, solid angles of 90°, 45° and 0° or 60°, 0° and −60° (pointing upwards) can be simultaneously received and evaluated.
In this case, an angle of 0° corresponds to a direction of emission or direction of reception parallel to a substrate of the vehicle. This measure allows low but collision-relevant objects below the sensor installation height, such as low bollards, granite blocks, low walls, stones and the like, to be detected. With a scanned spatial angle of -60°, objects that can be driven under, such as barriers, can also be detected by the ultrasonic sensor array.

In driving situations with slow driving speeds of less than 3 km/h, for example, ultrasonic sensor arrays directed in the direction of travel and ultrasonic sensor arrays directed against the direction of travel at the rear of the vehicle or ultrasonic sensor arrays arranged on the side can be used for distance measurement in a vertical solid angle range at 0° and at 45°.

The laterally arranged ultrasonic sensor arrays for detecting curbs can preferably be operated independently of the driving speed.

In driving situations with higher driving speeds of more than 3 km/h, for example, the spatial angle of 0° can be registered and evaluated by the front-side and rear-side ultrasonic sensor arrays.

Thus, according to a further embodiment, the transducer elements are switched to a reception state with a phase offset relative to the transmission state in such a way that reflected sound waves are received from three spatial angle regions spaced apart from one another, in particular spatial angular regions spaced apart by 45° or 60° and/or a multiple of 45° or 60° and converted to measurement data.

According to a further exemplary embodiment, the at least two converter elements are operated with a phase offset relative to one another in the reception state, which phase offset is equal to a phase offset in the transmission state. If the phase delay or the phase shift of the transducer elements in the reception state is selected to be equal to the phase shift of the transducer elements during transmission, the directional characteristics in the reception state and in the transmission state can be matched to one another analogously to the mechanical solution.

• 1 ein schematisches Ablaufdiagramm zum Veranschaulichen eines Verfahrens gemäß einer ersten Ausführungsform,
• 2 ein schematisches Ablaufdiagramm zum Veranschaulichen eines Verfahrens gemäß einer zweiten Ausführungsform,
• 3 eine Schnittdarstellung eines heckseitig an einem Fahrzeug angeordneten Ultraschallsensorarrays zum Veranschaulichen eines erfindungsgemäßen Verfahrens,
• 4 eine Schnittdarstellung eines heckseitig an einem Fahrzeug angeordneten Ultraschallsensorarrays zum Veranschaulichen eines erfindungsgemäßen Verfahrens gemäß einer dritten Ausführungsform und
• 5 eine Draufsicht auf ein Ultraschallsensorarray.

Preferred exemplary embodiments of the invention are explained in more detail below on the basis of greatly simplified schematic representations. show here

• 1 a schematic flowchart to illustrate a method according to a first embodiment,
• 2 a schematic flowchart to illustrate a method according to a second embodiment,
• 3 a sectional view of an ultrasonic sensor array arranged at the rear of a vehicle to illustrate a method according to the invention,
• 4 a sectional view of an ultrasonic sensor array arranged at the rear of a vehicle to illustrate a method according to the invention according to a third embodiment and
• 5 a plan view of an ultrasonic sensor array.

In the 1 a schematic flow chart is shown to illustrate a method 1 according to a first embodiment. Method 1 is used to control at least one ultrasonic sensor array 4 for emitting sound echoes in a detection area E. The ultrasonic sensor array 4 is in FIG 5 shown in detail and has at least two transducer elements 5, 5′, 5″, 5′″ spaced apart from one another in the vertical direction Z and/or in the horizontal direction Y.

The converter elements 5, 5′, 5″, 5″″ can be controlled 10 in a phase-shifted manner by a control unit 6 which is electrically connected to the converter elements 5, 5′, 5″, 5″″. As a result of this activation, a main axis H of the emitted sound echoes is tilted 12 with respect to a surface normal N of the ultrasonic sensor array 4.

In addition, for example, a driving situation can be determined 14 by the control unit 6, by means of which the precise solid angles or solid angle ranges are specified about which the main axis H of the emitted sound echoes is tilted 12 relative to a surface normal N or relative to a course of a subsurface U.

The 2 shows a schematic flowchart to illustrate a method 2 according to a second embodiment. Method 2 is used to control at least one ultrasonic sensor array 4 for receiving sound echoes reflected from a detection area E by a control unit 6.

As already described above, at least one ultrasonic sensor array 4 is used, which has a multiplicity of transducer elements 5 . The converter elements 5 are designed as partial sensors, so that each converter element 5 can be used separately for generating or emitting and for receiving sound waves in the form of sound echoes. The converter elements 5 of the ultrasonic sensor array 4 can preferably be controlled 16 by the control unit 6 in such a way that the received sound echoes, which are reflected back from the detection area E, are received 18 with a phase offset by the converter elements 5 .

By activating the receiving state of the transducer elements 5 with a phase offset, a solid angle range from which the sound echoes are received can be selected depending on the phase offset. This measure assigns a directional characteristic to the ultrasonic sensor array 4 . Depending on the configuration of the method 2, the directional characteristic can be changed 20. This can take place, for example, as a function of a position of the ultrasonic sensor array 4 on the subsurface U and/or as a function of a traffic situation or driving situation.

In the 3 a sectional view of an ultrasonic sensor array 4 arranged at the rear of a vehicle 8 is shown to illustrate a method 1 according to the invention.

The ultrasonic sensor array 4 is arranged in a lower portion of a rear bumper of the vehicle 8 . Such an installation position is fundamentally disadvantageous for ultrasonic sensors, since sound echoes reflected from the subsurface U are increasingly received. By using the ultrasonic sensor array 4 with two transducer elements 5, 5" arranged one above the other in the vertical direction Z, the direction of emission or the main axis H of the generated sound echoes can be rotated. This is illustrated by the arrow. This activation of the control unit 6 causes the main axis H of the emitted sound echoes are tilted 12 in relation to the surface normal N of the ultrasonic sensor array 4, as a result of which the generated sound echoes are generated parallel to the background U or at a solid angle of 0°.

In the exemplary embodiment shown, control unit 6 can be designed as dedicated control logic for at least one ultrasonic sensor array 4 . The control unit 6 can control one or more ultrasonic sensor arrays 4 at the same time.

The 4 1 shows a sectional view of an ultrasonic sensor array 4 arranged at the rear of a vehicle 8 to illustrate a method 2 according to the invention according to a third specific embodiment. Here, in particular, the last step 20 from 2 clarified.

Control unit 6 can preferably determine the driving situation or receive corresponding data on the driving situation. For example, the driving situation can be classified based on a vehicle speed. The corresponding measurement data for determining the vehicle speed and thus also the driving situation can be received by a GNSS sensor 7, for example.

Furthermore, in the 4 the negative installation angle β of the ultrasonic sensor array 4 compared to the orientation of the substrate U. In particular, when the vehicle 8 starts, predefined solid angles can be read out by the ultrasonic sensor array 4 by digital beamforming. In the illustrated embodiment, the solid angles 0°, 45° and 90° are rela tiv to the background U for the reception of sound echoes by corresponding phase differences between the transducer elements 5 set. As a result of this measure, a vertical directional characteristic for reception when the vehicle starts can be provided for improved detection of low objects relevant to a collision. The corresponding transducer elements 5 of the ultrasonic sensor array 4 are not shown for the sake of clarity.

In the 5 an ultrasonic sensor array 4 is shown as an example in a top view. Such ultrasonic sensor arrays 4 consist of a plurality of ultrasonic sensors or transducer elements 5, which are installed in a conventional housing 9, for example.

Such transducer elements 5 can be controlled by the control device 6 independently of one another to generate sound echoes and/or to receive reflected sound echoes.

The control device 6 can control the converter elements 5 in such a way that, for example, objects also in the vicinity of the vehicle 8 interfere with reflections of a subsurface U reliably and without superimposition. For this purpose, the lower two transducer elements 5", 5"' alone from the control unit 6 for generating sound echoes and the upper two transducer elements 5, 5' and/or the lower two transducer elements 5", 5"' for receiving reflected sound echoes are used.

The sound echoes are generated in the form of sound waves and can be generated continuously or in a pulsed form. In particular, a constant pulse width or a variable pulse width of the sound echoes generated can be set by the control device 6 .

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102018100567 A1 [0004]
• US 2020/0196527 A1 [0005]

Claims (10)

Method (1) for controlling at least one ultrasonic sensor array (4) for emitting sound echoes in a detection area (E), wherein the ultrasonic sensor array (4) has at least two transducer elements (5 ), wherein the converter elements (5) are controlled phase-shifted by a control unit (6) electrically connected to the converter elements (5) in order to tilt a main axis (H) of the emitted sound echoes with respect to a surface normal (N) of the ultrasonic sensor array (4). procedure after claim 1 , wherein a phase offset of the at least two transducer elements (5) of the ultrasonic sensor array (4) depending on an installation height of the ultrasonic sensor array (4) above a substrate (U) is adjusted and / or varied. Method (2) for controlling at least one ultrasonic sensor array (4) for receiving sound echoes reflected from a detection area (E) by a control device (6), wherein the ultrasonic sensor array (4) has at least two in the vertical direction (Z) and/or in the horizontal direction ( Y) has transducer elements (5) spaced apart from one another, the transducer elements (5) being switched into a reception state with a phase offset relative to a transmission state. procedure after claim 3 , wherein the transducer elements (5) are operated phase-shifted in a reception state such that reflected sound waves are received from at least one solid angle range and converted to measurement data. procedure after claim 4 , wherein a driving situation is determined, wherein the at least one solid angle or at least one solid angle range is set based on the determined driving situation. Procedure according to one of claims 3 until 5 , wherein the transducer elements (5) are switched to a reception state with a phase offset relative to the transmission state in such a way that reflected sound waves from three solid angle ranges spaced apart from one another, in particular solid angle ranges spaced apart by 45° or 60°, are received and converted to measurement data. Procedure according to one of claims 3 until 6 , wherein the at least two transducer elements (5) have a phase offset in the receiving state to one another, which is equal to a phase offset in the transmitting state. Control unit (6), wherein the control unit (6) is adapted to the method (1) according to one of Claims 1 until 2 and/or the method (2) according to any one of claims 3 until 7 to execute. Computer program which comprises instructions which, when the computer program is executed by a computer or a control unit (6), cause the latter to carry out the method (1) according to one of Claims 1 until 2 and/or the method (2) according to any one of claims 3 until 7 to execute. Machine-readable storage medium on which the computer program according to claim 9 is saved.

Images