Ultrasonic array transceiver unit and method for operating the ultrasonic array transceiver unit with a multidirectional transmission pattern

Abstract

The present invention relates to a method for operating an ultrasonic array transceiver unit, comprising the steps of emitting an ultrasonic pulse by controlling the ultrasonic array transceiver unit with a first parameter set and subsequently controlling the ultrasonic array transceiver unit with a second parameter set, wherein a first detection area of ​​the ultrasonic array transceiver unit controlled with the first parameter set differs from a second detection area of ​​the ultrasonic array transceiver unit controlled with the second parameter set, receiving the ultrasonic pulse reflected from an object and localizing the object on the basis of the received ultrasonic pulse.

Description

State of the art

[0001] The present invention relates to a method for operating an ultrasonic array transceiver unit and the associated ultrasonic array transceiver unit.

[0002] In today's automotive sector and similar industrial applications, ultrasonic sensors primarily use a single wall element to transmit and receive ultrasonic pulses. This limits the function of a single sensor to distance measurement. Ultrasonic array transceiver units, which operate with multiple transceiver elements, are under development and will bring significant improvements in functionality, such as angle measurement. At the same time, however, ultrasonic array sensors also present new challenges.

[0003] Ultrasonic array transceiver units face the challenge of minima in their transmission pattern; that is, the amplitude varies across the elevation and azimuth angles and has minima that deviate from 0° and 180°. These minima can lead to certain blind spots where objects cannot be detected. Beam steering, i.e., the phase shift of the transmitted ultrasonic pulse between two transmitters, allows the maxima of the emitted sound beam to be directed at desired angles. The disadvantage is that using two different sets of parameters to control the transmitted ultrasonic signal results in two separate pulse-echo sequences and doubles the system's cycle time. The cycle time is limited by the time the sensor needs to be excited before the intended transmission parameters are reached.It would be desirable to have an ultrasonic array transceiver unit and a method for operating it that allows the widest possible field of view without a significant increase in cycle time, thus enabling reliable object detection with minimal geometric limitations. Disclosure of the invention

[0004] The inventive method for operating an ultrasonic array transceiver unit with the features of claim 1, and the associated ultrasonic array transceiver unit with the features of claim 6, have the advantage that the directional characteristics of the ultrasonic array transceiver unit can be improved with a reduced system cycle time. According to the invention, this is achieved by emitting an ultrasonic pulse in one step by controlling the ultrasonic array transceiver unit with a first parameter set and subsequently controlling the ultrasonic array transceiver unit with a second parameter set. A first detection range of the ultrasonic array transceiver unit controlled by the first parameter set differs from a second detection range of the ultrasonic array transceiver unit controlled by the second parameter set.In a subsequent step, the ultrasound pulse reflected from an object is received, and the object is then localized based on the received ultrasound pulse. According to the invention, the first and second parameter sets comprise parameters that influence the detection range of the emitted ultrasound pulse, such that by changing the parameter set, two detection ranges can be covered with a single ultrasound pulse. The first detection range preferably covers the minima of the second detection range, and vice versa, thus improving the detection range of the ultrasound pulse. Localization allows, in particular, the determination of the object's distance and direction relative to the ultrasound array transceiver unit. The distance to the object is determined, in particular, by means of a time-of-flight analysis, and the direction by determining the phase shift of the received reflected ultrasound pulse.

[0005] Preferably, the ultrasound pulse can be modified to additional parameter sets during transmission. By controlling the ultrasound array transceiver unit with a first parameter set and subsequently with a second parameter set, the transmitted ultrasound pulse can cover multiple detection ranges. Changing the parameter set does not require any lengthy setup time for the ultrasound array transceiver unit, as would be the case, for example, with two consecutive ultrasound pulses controlled by different parameter sets. This allows for a reduction in cycle time while improving the detection range.

[0006] The dependent claims describe preferred embodiments of the invention.

[0007] The first and second parameter sets preferably include a phase shift, amplitude, and / or frequency of the ultrasound pulse as parameters, with at least one of the parameters being changed from the first to the second parameter set. In particular, the phase shift is changed so that the emitted ultrasound pulse can be beam-steered in different directions.

[0008] Preferably, after half the transmission time, the first parameter set is changed to the second parameter set. This ensures a sufficiently long activation of the ultrasound array transceiver unit with both the first and second parameter sets to improve the detection range of the transmitted ultrasound pulse.

[0009] The first set of parameters is preferably continuously modified relative to the second set of parameters. Thus, the first detection range also continuously changes relative to the second detection range, enabling coverage of detection areas between the first and second detection ranges. For example, the first detection range can be oriented downwards due to a first phase shift, and a second detection range can be oriented upwards due to a second phase shift. The continuous modification of the first and second phase shifts causes the detection range of the ultrasound array transceiver unit to shift from bottom to top, also covering areas between the first and second detection ranges.

[0010] Preferably, the received ultrasound signal reflected from the object is assigned to a first and / or second parameter set to locate the object. For example, the time difference between the first and second parameter sets can enable precise time-of-flight determination and distance measurement. Furthermore, increasing or decreasing the duration of the first parameter set relative to the second parameter set can determine whether the ultrasound array transceiver is approaching or moving away from the object. If the detection range changes due to a change in frequency, determining the frequency of the received ultrasound pulse can reveal whether the ultrasound signal was reflected from the first or second detection range.

[0011] Furthermore, the invention relates to an ultrasonic array transceiver unit comprising a first transceiver element and a second transceiver element, wherein the ultrasonic array transceiver unit is configured to execute a previously described method. This allows the detection range of the ultrasonic array transceiver unit to be increased and minima to be reduced with a short cycle time. Thus, the ultrasonic array transceiver unit can enable reliable detection of objects in its environment.

[0012] It is further preferred that the distance between the first transceiver element and the second transceiver element is less than or greater than a multiple of half the wavelength of the ultrasonic array transceiver unit. According to the invention, this distance refers to the distance between the centers of the first and second transceiver elements. In the prior art, the distance between the transceiver elements is typically a multiple of the wavelength of the ultrasound in air divided by 2, in order to reduce minima in the detection range. By controlling the transceiver elements using the method according to the invention, a reduction of the minima in the detection range is possible without this geometric limitation. Brief description of the drawings

[0013] A preferred embodiment of the invention is described in detail below with reference to the accompanying drawings. The drawing shows: Fig. 1 a schematic time-frequency diagram of a method for operating an ultrasonic array transceiver unit according to a preferred embodiment of the invention and Fig. 2 A schematic representation of the ultrasound array transceiver unit, according to the preferred embodiment of the invention, with a first detection area and a second detection area. Embodiments of the invention

[0014] Preferably, all identical components, elements and / or units in all figures are provided with the same reference numerals.

[0015] The following refers to the Fig. 1 and Fig. 2 a method for operating an ultrasonic array transceiver unit 1 and the associated ultrasonic array transceiver unit 1 are described in detail.

[0016] Fig. Figure 1 shows a line diagram representing the amplitude 15 of an ultrasonic pulse 10 at the ultrasonic array transceiver unit 1 during a procedure for operating the ultrasonic array transceiver unit 1 as a function of time t.

[0017] At the beginning of the procedure, the ultrasound array transceiver unit 1 is first controlled with a first parameter set 11 and then with a second parameter set 12 to emit an ultrasound pulse 10. The first parameter set 11 and the second parameter set 12 include the amplitude 15 as a parameter, which is higher in the first parameter set 11 than in the second parameter set 12. The ultrasound array transceiver unit 1 has a different detection range for different amplitudes 15, so that a first detection range 13 can be assigned to the control with the first parameter set 11, and a second detection range 14 can be assigned to the control with the second parameter set 12, which differs from the first detection range 13.

[0018] As an alternative to the amplitude 15, the first and second parameter sets 13, 14 can, for example, include a first and second drive voltage for the ultrasonic array transceiver unit, which directly affects the emitted amplitude 15.

[0019] A settling time t1 elapses before the ultrasound arrays in receiver unit 1 are excited to the defined amplitude 15 by the first parameter set 11. Furthermore, the amplitude-time diagram shows a decay time t3 after the ultrasound array transceiver unit 1 is no longer driven with the second parameter set 12. In addition, the diagram shows a transition time t2, which is required to adapt the ultrasound array transceiver unit 1 from the first parameter set 11 to the second parameter set 12. The transition time t2 is significantly shorter than the settling or decay times t1 and t3, so that by driving the ultrasound array transceiver unit 1 with a first parameter set 11 and a second parameter set 12, the cycle time can be reduced compared to emitting two ultrasound pulses 10, each with one parameter set.

[0020] After a waiting period t4, during which the ultrasound pulse 10 propagates in space and is reflected by objects 4 in the first detection area 13 or second detection area 14, the reflected ultrasound pulse 20 is received by the ultrasound array transceiver unit 1 in a step S2. The received ultrasound signal 20 can, for example, have two different amplitudes 15, which can be assigned to the first parameter set 11 and the second parameter set 12. Due to the propagation of the ultrasound pulse 10 in space, the amplitude 15 of the received reflected ultrasound pulse 20 has attenuated.

[0021] The object 4, from which the ultrasound pulse 20 was reflected, can be located based on the received reflected ultrasound pulse 20. In particular, the distance between the ultrasound array transceiver unit 1 and the object 4 can be determined by means of a time-of-flight analysis between the transmitted and received ultrasound pulses. The direction of the object 4 relative to the ultrasound array transceiver unit 1 can be determined, for example, by the phase shift between the received signals of a first transceiver unit 2 and a second transceiver unit 3 of the ultrasound array transceiver unit 1.

[0022] The control of the ultrasonic array transceiver unit 1 is changed from the first parameter set 11 to the second parameter set 12 after half a transmission time. In addition to the amplitude 15, the first parameter set 11 and the second parameter set 12 can also have a phase shift, which changes from the first parameter set 11 to the second parameter set 12.

[0023] Fig. Figure 2 schematically shows the ultrasound array transceiver unit 1 with the first detection area 13 and the second detection area 14. The first detection area 13 and the second detection area 14 each have a central main lobe and two secondary lobes separated from it by minima. The second detection area 14 is arranged at an angle α to the first detection area 13, such that the main lobe of the second detection area 14 covers a minima of the first detection area 13.

[0024] The first detection area 13 and the second detection area 14 are detected with an ultrasonic pulse 10, in which the ultrasonic array transceiver unit 1 is first controlled with the first parameter set 11 and then with the second parameter set 12. The angular offset between the first detection area 13 and the second detection area 14 can be achieved by beam steering through a phase shift between the ultrasonic pulse 10 emitted by the first transceiver element 2 and the second transceiver element 3.

[0025] The phase shift can be changed discontinuously between the first parameter set 11 and the second parameter set 12, so that the first detection area 13 switches abruptly to the second detection area 14.

[0026] Alternatively, the phase shift according to the first parameter set 11 can be continuously changed to the phase shift according to the second parameter set 12, whereby the first detection range 13 transitions smoothly into the second detection range 14.

[0027] The object 4 is located in the second detection area 14, at which the emitted ultrasound pulse 10 is reflected and sent back to the ultrasound array transceiver unit 1 as a reflected ultrasound pulse 20. Due to the directivity of the first detection area 13, it would not have been able to detect the object 4.

[0028] The first transceiver element 2 and the second transceiver element 3 are arranged at a distance d from each other in the ultrasonic array transceiver unit 1, wherein the distance d is less than or greater than a multiple of half the wavelength of the ultrasonic pulse 10 emitted by the ultrasonic array transceiver unit 1. The distance d is determined from a center point of the first transceiver element 2 to a center point of the second transceiver element 3.

[0029] Thus, by emitting the ultrasound pulse 10 and controlling the ultrasound array transceiver unit 1 with the first parameter set 11 and subsequently the second parameter set 12, the detection range of the emitted ultrasound pulse can be increased without the ultrasound array transceiver unit 1 having to oscillate or decay. This allows the detection performance of the ultrasound array transceiver unit 1 to be improved with a reduced cycle time.

Claims

[1] Method for operating an ultrasonic array transceiver unit, comprising the steps: - Emitting (S1) an ultrasonic pulse (10) by controlling the ultrasonic array transceiver unit (1) with a first parameter set (11) and subsequently controlling the ultrasonic array transceiver unit (1) with a second parameter set (12), wherein a first detection area (13) of the ultrasonic array transceiver unit (1) controlled by the first parameter set (11) differs from a second detection area (14) of the ultrasonic array transceiver unit (1) controlled by the second parameter set (12), - Receiving (S2) the ultrasound pulse (20) reflected from an object (4) and - Localization of the object (4) based on the received ultrasound pulse (20). [2] Method according to claim 1, wherein the first parameter set (11) and the second parameter set (12) comprise a phase shift, an amplitude (15) and / or a frequency of the ultrasound pulse (10) as parameters, wherein at least one of the parameters is changed from the first parameter set to the second parameter set. [3] Method according to one of the preceding claims, wherein after half a transmission time the first parameter set (11) is changed to the second parameter set (12). [4] Method according to one of the preceding claims, wherein the first parameter set (11) is continuously changed to the second parameter set (12). [5] Method according to any of the preceding claims, wherein the received ultrasound signal (20) reflected at the object (4) is assigned to a first parameter set (11) and / or second parameter set (12) to locate the object (4). [6] Ultrasound array transceiver unit comprising a first transceiver element (2) and a second transceiver element (3), wherein the ultrasound array transceiver unit (1) is configured to perform a method according to one of the preceding claims. [7] Ultrasound array transceiver unit according to claim 6, wherein a distance (d) of the first transceiver element (2) to the second transceiver element (3) is smaller or larger than a multiple of half a wavelength of the ultrasound array transceiver unit (1).

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