CN111624608B

CN111624608B - Ultrasonic ranging method and device

Info

Publication number: CN111624608B
Application number: CN202010446365.2A
Authority: CN
Inventors: 刘楷; 金荣; 徐红如
Original assignee: Nanjing Yingruichuang Electronic Technology Co Ltd
Current assignee: Nanjing Yingruichuang Electronic Technology Co Ltd
Priority date: 2020-05-25
Filing date: 2020-05-25
Publication date: 2023-02-28
Anticipated expiration: 2040-05-25
Also published as: CN111624608A

Abstract

The invention relates to an ultrasonic ranging method and device. The ultrasonic ranging method is used for respectively sending first ultrasonic waves and second ultrasonic waves with different frequencies according to the number of preset pulses and acquiring first echo waves and second echo waves. And calculating a first time length according to the first ultrasonic wave and the first echo, and calculating a second time length according to the second ultrasonic wave and the second echo. When the first duration and the second duration are different, reducing the number of preset pulses and recalculating the first duration and the second duration; and when the first duration is the same as the second duration, calculating the distance to be measured according to the first duration. According to the ultrasonic ranging method, when the first time length is different from the second time length, the distance to be measured is a measuring blind area of at least one of the first ultrasonic wave and the second ultrasonic wave. At this time, the number of pulses is gradually reduced, so that the measurement dead zones of the first ultrasonic wave and the second ultrasonic wave can be reduced, and the measurement dead zone of the ultrasonic ranging method is reduced.

Description

Ultrasonic ranging method and device

Technical Field

The invention relates to the technical field of sound wave distance measurement, in particular to an ultrasonic distance measurement method and device.

Background

Ultrasonic waves are often used for distance measurement because of their strong directivity, slow energy consumption, and long propagation distance in a medium.

In the conventional art, generally, an ultrasonic wave is transmitted to a target object by an ultrasonic transmitter, by calculating a time difference between transmission of the ultrasonic wave and acquisition of an echo, and calculating a distance between the ultrasonic transmitter and the target object by the time difference.

The applicant found in the course of implementing the conventional technique that: the traditional ultrasonic ranging method has a large blind area.

Disclosure of Invention

Therefore, it is necessary to provide an ultrasonic ranging method and apparatus for solving the problem of a large blind area in the conventional ultrasonic ranging method.

An ultrasonic ranging method comprising:

sending a first ultrasonic wave and a second ultrasonic wave in a preset pulse number, wherein the first ultrasonic wave has a first frequency, the second ultrasonic wave has a second frequency, and the first frequency is greater than the second frequency;

acquiring a first echo corresponding to the first ultrasonic wave and a second echo corresponding to the second ultrasonic wave;

calculating a time difference between the sending time of the first ultrasonic wave and the receiving time of the first echo to obtain a first duration; and a time difference between the sending time of the second ultrasonic wave and the receiving time of the second echo is obtained to obtain a second time length;

if the first time length is different from the second time length, reducing the number of the preset pulses, and repeatedly executing the steps until the first time length is equal to the second time length;

and calculating the distance to be measured according to the first duration and the first frequency.

In one embodiment, before calculating the distance to be measured according to the first duration and the first frequency, the method further includes:

sending a third ultrasonic wave with a third frequency smaller than the second frequency in a preset pulse number;

acquiring a third echo corresponding to the third ultrasonic wave;

calculating a time difference value between the sending time of the third ultrasonic wave and the receiving time of the third echo to obtain a third time length;

if the third duration is different from the first duration and the second duration, reducing the number of the preset pulses, and repeatedly executing the steps until the third duration is equal to the first duration and the second duration.

In one embodiment, the transmitting the first ultrasonic wave and the second ultrasonic wave in the preset number of pulses comprises

Acquiring a sending digital signal, wherein the sending digital signal comprises the preset pulse number and the first frequency or the second frequency;

converting the transmit digital signal to an analog signal;

and transmitting the first ultrasonic wave or the second ultrasonic wave according to the analog signal.

In one embodiment, before the transmitting the first ultrasonic wave or the second ultrasonic wave according to the analog signal, the method further includes:

and amplifying the amplitude of the analog signal by a preset gain factor.

In one embodiment, said first duration is different from said second duration; the repeatedly executing the above steps until the first duration is equal to the second duration further includes:

and increasing the preset gain multiple.

In one embodiment, before the sending the first ultrasonic wave or the second ultrasonic wave according to the analog signal, the method further includes:

and suppressing the oscillation signal of the analog signal.

An ultrasonic ranging device comprising:

a first transmission circuit configured to transmit a first ultrasonic wave at a preset number of pulses and a first frequency;

a first detection circuit configured to acquire a first echo;

a second transmission circuit configured to transmit a second ultrasonic wave at a preset number of pulses and a second frequency;

a second detection circuit configured to acquire a second echo;

the controller is connected with the first sending circuit, the first detection circuit, the second sending circuit and the second detection circuit, has a preset pulse number, the first frequency and the second frequency, and is used for controlling the first sending circuit to send first ultrasonic waves and controlling the second sending circuit to send second ultrasonic waves;

the controller is configured to: calculating a time difference between the sending time of the first ultrasonic wave and the receiving time of the first echo to obtain a first duration; and the time difference between the sending time of the second ultrasonic wave and the receiving time of the second echo wave to obtain a second time length; if the first duration is different from the second duration, reducing the number of the preset pulses, and retransmitting the first ultrasonic wave and the second ultrasonic wave to obtain the first echo and the second echo until the first duration is equal to the second duration; and calculating the distance to be measured according to the first duration and the first frequency.

In one embodiment, the ultrasonic ranging apparatus further comprises:

a third transmission circuit configured to transmit the first ultrasonic wave at a preset number of pulses and a first frequency;

a third detection circuit configured to acquire a first echo;

the controller is further configured to: calculating a time difference value between the sending time of the third ultrasonic wave and the receiving time of the third echo to obtain a third time length; if the third duration is different from the first duration and the second duration, reducing the number of the preset pulses, and repeatedly executing the steps until the third duration is equal to the first duration and the second duration.

In one embodiment, the first transmitting circuit or the second transmitting circuit includes:

the digital-to-analog converter is connected with the controller, is configured to acquire a sending digital signal sent by the controller and converts the sending digital signal into an analog signal;

an ultrasonic transmitter connected with the digital-to-analog converter and configured to transmit the first ultrasonic wave or the second ultrasonic wave according to the analog signal.

In one embodiment, the first transmitting circuit or the second transmitting circuit further comprises:

a gain control circuit connected between the digital-to-analog converter and the ultrasonic transmitter and configured to amplify the amplitude of the analog signal by a preset gain factor; the controller is configured to: if the first time length is different from the second time length, reducing the number of the preset pulses, increasing the preset gain multiple, and re-sending the first ultrasonic wave and the second ultrasonic wave to obtain a first echo and a second echo until the first time length is equal to the second time length;

an oscillation suppression circuit connected between the gain control circuit and the ultrasonic transmitter and configured to suppress an oscillation signal of the analog signal.

According to the ultrasonic ranging method, the first ultrasonic waves and the second ultrasonic waves with different frequencies are respectively sent according to the number of the preset pulses, and the first echo and the second echo are obtained. And calculating a first time length according to the first ultrasonic wave and the first echo, and calculating a second time length according to the second ultrasonic wave and the second echo. When the first duration and the second duration are different, reducing the number of preset pulses and recalculating the first duration and the second duration; and when the first duration is the same as the second duration, calculating the distance to be measured according to the first duration. According to the ultrasonic ranging method, when the first time length is different from the second time length, the distance to be measured is a measuring blind area of at least one of the first ultrasonic wave and the second ultrasonic wave. At this time, by gradually reducing the number of pulses, the measurement blind areas of the first ultrasonic wave and the second ultrasonic wave can be reduced, thereby reducing the measurement blind area of the ultrasonic ranging method.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic flow chart of an ultrasonic ranging method according to an embodiment of the present application;

FIG. 2 is a schematic flow chart of an ultrasonic ranging method according to another embodiment of the present application;

FIG. 3 is a schematic flow chart of an ultrasonic ranging method according to another embodiment of the present application;

FIG. 4 is a schematic flow chart of an ultrasonic ranging method according to another embodiment of the present application;

FIG. 5 is a schematic flow chart illustrating step S100 according to an embodiment of the present application;

FIG. 6 is a schematic flowchart of step S100 in another embodiment of the present application;

FIG. 7 is a schematic flow chart of an ultrasonic ranging method according to another embodiment of the present application;

FIG. 8 is a schematic flow chart of step S100 according to another embodiment of the present application;

FIG. 9 is a comparison of a first ultrasonic waveform in an embodiment of the present application;

FIG. 10 is a schematic structural diagram of an ultrasonic ranging device according to an embodiment of the present application;

FIG. 11 is a schematic structural diagram of an ultrasonic ranging device according to another embodiment of the present application;

FIG. 12 is a schematic structural diagram of an ultrasonic ranging device according to another embodiment of the present application;

fig. 13 is a schematic structural diagram of an ultrasonic ranging device according to another embodiment of the present application.

Wherein, the meanings represented by the reference numerals are as follows:

10. an ultrasonic ranging device;

101. a controller;

110. a first transmitting circuit;

120. a first detection circuit;

130. a second transmitting circuit;

140. a second detection circuit;

150. a third transmitting circuit;

160. and a third detection circuit.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will recognize without departing from the spirit and scope of the present invention.

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings). In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like are used in the orientations and positional relationships indicated in the drawings, which are based on the orientations and positional relationships indicated in the drawings, and are used for convenience of description and simplicity of description, but do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the conventional technology, when measuring a distance to a target object by using an ultrasonic ranging technique, an ultrasonic transmitter generally transmits ultrasonic waves to the target object, and an echo receiver receives echoes of the ultrasonic waves. The distance to be measured between the target object and the ultrasonic wave can be calculated by calculating the time difference between the sending time of the ultrasonic wave and the receiving time of the echo wave. During the transmission of the ultrasonic waves, the ultrasonic transmitter continuously transmits a number of pulses of the ultrasonic waves. When the number of pulses of the ultrasonic wave is too small, the ultrasonic wave energy is low, and the distance to be measured cannot be measured; when the number of ultrasonic pulses is large and the distance to be measured is small, the sending time of the ultrasonic waves is overlapped with the receiving time of the echo waves, the distance to be measured cannot be measured, and therefore a measuring blind area is caused.

Based on the above problems, the present application provides an ultrasonic ranging method and apparatus. The ultrasonic ranging device can execute the ultrasonic ranging method. The ultrasonic ranging method can adjust the number of pulses for sending ultrasonic waves according to the distance to be measured between the ultrasonic ranging method and a target object. Therefore, when the distance to be measured is large, the number of pulses is enough, and the energy of ultrasonic waves is enough; when the distance to be measured is smaller, the number of pulses is reduced, so that the measurement blind area is reduced.

In the embodiments of the present application, the ultrasonic ranging method requires to transmit at least two ultrasonic waves at the same time, and the following embodiments of the present application describe embodiments in which the ultrasonic ranging method transmits two ultrasonic waves and three ultrasonic waves at the same time, respectively. The ultrasonic waves have different frequencies. For convenience of description, the ultrasonic waves are named a first ultrasonic wave, a second ultrasonic wave, and a third ultrasonic wave, respectively; the frequency corresponding to the first ultrasonic wave is a first frequency, the frequency corresponding to the second ultrasonic wave is a second frequency, and the frequency corresponding to the third ultrasonic wave is a third frequency. And will not be described in detail.

As shown in fig. 1, the present application provides an ultrasonic ranging method, including the following steps:

s110, sending a first ultrasonic wave and a second ultrasonic wave in a preset pulse number, wherein the first ultrasonic wave has a first frequency, the second ultrasonic wave has a second frequency, and the first frequency is greater than the second frequency.

The first ultrasonic wave and the second ultrasonic wave are transmitted simultaneously. When the first ultrasonic wave and the second ultrasonic wave are sent, the number of pulses of the first ultrasonic wave and the number of pulses of the second ultrasonic wave are the same and are the preset number of pulses. The number of preset pulses is an integer greater than or equal to 2. The frequency corresponding to the first ultrasonic wave is a first frequency, the frequency corresponding to the second ultrasonic wave is a second frequency, and the first frequency is greater than the second frequency.

For example, the preset number of pulses may be 32, the first frequency may be 80KHz, and the second frequency may be 55KHz. At this time, a 32-pulse first ultrasonic wave is sent, and the frequency of the first ultrasonic wave is 80KHz; meanwhile, a 32-pulse second ultrasonic wave is transmitted, and the frequency of the second ultrasonic wave is 55KHz.

It is to be understood that in this embodiment, the preset number of pulses, the first frequency and the second frequency are illustrated in only one common case. In other embodiments, the number of preset pulses may also be 2, and may also be 16 or 48. The frequency of the first ultrasonic wave can also be 100KHz or 60KHz; the frequency of the second ultrasonic wave can also be 52KHz or 58KHz. The skilled person can adjust the ultrasonic energy requirement according to the distance measurement, without limitation.

S120, a first echo corresponding to the first ultrasonic wave and a second echo corresponding to the second ultrasonic wave are obtained.

After the first ultrasonic wave and the second ultrasonic wave are sent, the echo corresponding to the first ultrasonic wave and the echo corresponding to the second ultrasonic wave can be obtained. For convenience of description, in the embodiments of the present application, an echo corresponding to a first ultrasonic wave is named a first echo, and an echo corresponding to a second ultrasonic wave is named a second echo.

S130, calculating a time difference value between the sending time of the first ultrasonic wave and the receiving time of the first echo to obtain a first duration; and obtaining a second time length according to a time difference between the sending time of the second ultrasonic wave and the receiving time of the second echo.

The transmission timing of the first ultrasonic wave is a timing when the first ultrasonic wave is transmitted. The reception time of the first echo is a time when the first echo is received. Therefore, the time difference between the sending time of the first ultrasonic wave and the receiving time of the first echo is the time length used by the first ultrasonic wave to make one round trip at the distance to be measured. Here, the time difference is calculated to obtain the first duration.

Similarly, the transmission timing of the second ultrasonic wave is a timing when the second ultrasonic wave is transmitted. The reception time of the second echo is a time when the second echo is received. Therefore, the time difference between the sending time of the second ultrasonic wave and the receiving time of the second echo is the time length used by the second ultrasonic wave to make one round trip at the distance to be measured. Here, the time difference is calculated to obtain the second duration.

S140, if the first duration is different from the second duration, reducing the number of the preset pulses, and repeating the above steps until the first duration is equal to the second duration.

As is known from the above description, when the number of ultrasonic pulses is large and the distance to be measured is small, the transmission time of the ultrasonic wave may overlap with the reception time of the echo, thereby causing a measurement blind area. Here, when the distance to be measured is a measurement blind area of at least one of the first ultrasonic wave and the second ultrasonic wave, the first time period and the second time period are inevitably different from each other. Or, it can be said that when the first time length is different from the second time length, the distance to be measured is a measurement blind area of at least one of the first ultrasonic wave and the second ultrasonic wave.

At this time, that is, when the first duration and the second duration are different, the preset number of pulses is decreased. When the distance to be measured is a measurement blind area of at least one of the first ultrasonic wave and the second ultrasonic wave, the distance to be measured is smaller. At this time, the reduction of the number of pulses does not reduce the energy of the first ultrasonic wave and the second ultrasonic wave to such an extent that the distance to be measured cannot be measured. By reducing the number of pulses, the overlapping of the sending time of the ultrasonic waves and the receiving time of the echo waves can be avoided, and therefore the blind area of ultrasonic distance measurement is reduced.

S150, calculating the distance to be measured according to the first duration and the first frequency.

And when the first duration is the same as the second duration, calculating the distance to be measured according to the first duration and the first frequency. As known from the above description, the first frequency is greater than the second frequency, and therefore the first wavelength corresponding to the first ultrasonic wave is also smaller than the second wavelength corresponding to the second ultrasonic wave. Therefore, the sending time of the first ultrasonic wave is easier to count, and the distance to be measured is calculated according to the first duration and the first frequency.

More specifically, as shown in fig. 2, before step S110, the ultrasonic ranging method of the present application may first execute step S001 to obtain the number of preset pulses. The preset number of pulses may be a preset fixed number for defining the number of pulses for transmitting the first ultrasonic wave and the second ultrasonic wave.

Step S140 specifically includes: and S142, judging whether the first time length is equal to the second time length.

If the first duration is equal to the second duration, step S150 is performed.

If the first duration is not equal to the second duration, step S144 is executed to decrement the preset number of pulses by one. And after the number of the preset pulses is reduced by one, calculating the first time length and the second time length again according to the number of the reduced preset pulses until the first time length is equal to the second time length.

For example, when the preset number of pulses acquired in step S001 is 32, the first ultrasonic wave and the second ultrasonic wave are transmitted in 32 pulses, and the first time period and the second time period are calculated based on the transmission of the first ultrasonic wave and the second ultrasonic wave. And if the first time length is not equal to the second time length, sending the first ultrasonic wave and the second ultrasonic wave by 31 pulses, and calculating the first time length and the second time length again according to the first time length and the second time length. This step is repeated until the first time period is equal to the second time period.

According to the ultrasonic ranging method, when the first time length is different from the second time length, the distance to be measured is a measuring blind area of at least one of the first ultrasonic wave and the second ultrasonic wave. At this time, by gradually reducing the number of pulses, the measurement blind areas of the first ultrasonic wave and the second ultrasonic wave can be reduced, thereby reducing the measurement blind area of the ultrasonic ranging method.

In one embodiment, as shown in fig. 3, before step S150, the ultrasonic ranging method of the present application further includes the following steps:

s210, sending a third ultrasonic wave with a third frequency smaller than the second frequency according to the preset pulse number.

As is apparent from the above description, the ultrasonic ranging method of the present application requires at least two ultrasonic waves to be transmitted simultaneously. In the present embodiment, the ultrasonic ranging method transmits three ultrasonic waves. That is, on the basis of the above-described embodiment, the ultrasonic ranging method also transmits the third ultrasonic wave. The number of pulses of the third ultrasonic wave is the same as that of the first pulse and the second pulse, and the number of the pulses is the preset number. The frequency corresponding to the third ultrasonic wave is a third frequency. Here, the third frequency is smaller than the second frequency. For example, the third frequency may be 48KHz, or 50KHz or 45KHz.

Here, step S210 is parallel to step S110 such that the first ultrasonic wave, the second ultrasonic wave, and the third ultrasonic wave are transmitted simultaneously.

And S220, acquiring a third echo corresponding to the third ultrasonic wave.

And after the third ultrasonic wave is sent, the echo corresponding to the third ultrasonic wave can be obtained. For convenience of description, the echo corresponding to the third ultrasonic wave is named a third echo.

And S230, calculating a time difference between the sending time of the third ultrasonic wave and the receiving time of the third echo to obtain a third time length.

The transmission timing of the third ultrasonic wave is a timing when the third ultrasonic wave is transmitted. The reception time of the third echo is a time when the third echo is received. Therefore, the time difference between the sending time of the third ultrasonic wave and the receiving time of the third echo is the time length used by the third ultrasonic wave to make one round trip at the distance to be measured. Here, the time difference is calculated to obtain a third time period.

Similarly, step S230 is parallel to step S130.

S240, if the third duration is different from the first duration and the second duration, reducing the number of preset pulses, and repeatedly executing the steps until the third duration is equal to the first duration and the second duration.

As is known from the above description, when the number of ultrasonic pulses is large and the distance to be measured is small, the transmission time of the ultrasonic wave may overlap with the reception time of the echo, thereby causing a measurement blind area. Here, when the distance to be measured is a measurement blind area of at least one of the first ultrasonic wave, the second ultrasonic wave, and the third ultrasonic wave, the first time period, the second time period, and the third time period are not necessarily identical. Or, it can be said that when the first time length, the second time length, and the third time length are not completely the same, it indicates that the distance to be measured is a measurement blind area of at least one of the first ultrasonic wave, the second ultrasonic wave, and the third ultrasonic wave.

At this time, namely when the first time length, the second time length and the third time length are different, the number of the preset pulses is reduced. When the distance to be measured is a measurement blind area of at least one of the first ultrasonic wave, the second ultrasonic wave and the third ultrasonic wave, the distance to be measured is smaller. At this time, the reduction of the number of pulses does not reduce the energy of the first ultrasonic wave, the second ultrasonic wave and the third ultrasonic wave to a degree that the distance to be measured cannot be measured. By reducing the number of pulses, the overlapping of the sending time of the ultrasonic waves and the receiving time of the echo waves can be avoided, and therefore the blind area of ultrasonic ranging is reduced.

More specifically, step S240 specifically includes: and S242, judging whether the first time length, the second time length and the third time length are equal.

If the first duration is equal to the second duration, step S150 is performed.

If the first duration, the second duration and the third duration are not equal to each other, step S244 is executed to decrement the preset number of pulses by one. And after the number of the preset pulses is reduced by one, calculating the first time length, the second time length and the third time length again according to the number of the preset pulses after the number of the preset pulses is reduced by one until the first time length, the second time length and the third time length are equal.

In order to more intuitively understand the implementation process of the ultrasonic ranging method of the present application, a flowchart of the ultrasonic ranging method of the present application may be shown in fig. 4, in which steps S210 to S240 and steps S110 to S140 are combined in pairs. And will not be described in detail.

In one embodiment, as shown in fig. 5, the step S110 of the ultrasonic ranging method of the present application includes:

and S112, acquiring a sending digital signal, wherein the sending digital signal comprises a preset pulse number and a first frequency or a second frequency.

A transmission digital signal is acquired. Here, the transmission digital signal means: the signal is a digital signal that is used to transmit the ultrasonic waves. Taking the case where the ultrasonic ranging method requires the simultaneous transmission of the first ultrasonic wave and the second ultrasonic wave, the transmission digital signal may include a first transmission digital signal and a second transmission digital signal. The first transmission digital signal is used for realizing the transmission of the first ultrasonic wave; the second transmission digital signal is used to realize transmission of the second ultrasonic wave.

As is known from the above description, the physical characteristics of the first ultrasonic wave include a first frequency and a preset number of pulses; the physical characteristics of the second ultrasonic wave include a second frequency and a preset number of pulses. Therefore, the transmission digital signal includes a preset number of pulses and the first frequency or the second frequency. The first sending digital signal comprises a preset pulse number and a first frequency; the second transmission digital signal includes a preset number of pulses and a second frequency.

S114, the transmission digital signal is converted into an analog signal.

After the transmit digital signal is obtained, the transmit digital signal may be converted to an analog signal by a digital-to-analog converter.

S116, the first ultrasonic wave or the second ultrasonic wave is sent according to the analog signal.

Here, the analog signal can be converted into ultrasound by an ultrasound transmitter. The ultrasonic transmitter here includes a piezoelectric ceramic ultrasonic transmitter.

Further, as shown in fig. 6, before step S116, the ultrasonic ranging method of the present application further includes: s118, amplifying the amplitude of the analog signal by a predetermined gain.

Specifically, in order to increase the energy of the ranging ultrasonic wave, the amplitude of the analog signal may be amplified by a predetermined gain before the first ultrasonic wave or the second ultrasonic wave is transmitted according to the analog signal. Here, the preset gain multiple may be a rational number greater than 1. Generally, the amplitude of the analog signal may be amplified by a gain control circuit. No further description is given.

Furthermore, when the step S110 includes the step S118, as shown in fig. 7, the ultrasonic ranging method according to the present application, after the step S142, may further include the steps of:

and S146, increasing the preset gain multiple.

Specifically, as is known from the above description, when the number of pulses of the ultrasonic wave is reduced, the energy of the ultrasonic wave is also reduced. Here, when the number of pulses of the ultrasonic wave is reduced, the amplitude of the ultrasonic wave can be increased to keep the energy of the ultrasonic wave constant.

In step S118, the ultrasonic ranging method of the present application may amplify the amplitude of the analog signal by a predetermined gain factor, thereby increasing the energy of the ultrasonic wave. Therefore, when the number of pulses of the ultrasonic wave is reduced, the energy of the ultrasonic wave may be increased by increasing the preset gain factor.

It is to be understood that, in this embodiment, an embodiment of "increasing the energy of the ultrasonic wave by increasing the preset gain multiple" is described by taking only a case where the first ultrasonic wave and the second ultrasonic wave are transmitted by the ultrasonic ranging method as an example. It will be understood by those skilled in the art that in other embodiments, when the ultrasonic ranging method transmits the first ultrasonic wave, the second ultrasonic wave, and the third ultrasonic wave, the energy of the ultrasonic waves may be increased by increasing the preset gain factor as well. The mode of increasing the preset gain multiple of the third ultrasonic wave is the same as the first ultrasonic wave and the second ultrasonic wave, and the description is omitted.

In an embodiment, as shown in fig. 8, before step S116, the ultrasonic ranging method of the present application may further include:

s119, the oscillation signal of the analog signal is suppressed.

Specifically, after the transmission digital signal is converted into the analog signal, the analog signal may generate an oscillation signal, and the oscillation signal may affect the waveform of the analog signal, so that the oscillation signal of the analog signal may be suppressed before step S116.

As shown in fig. 8, when step S110 includes both steps S118 and S119, step S119 may be located after step S118, so as to avoid amplifying the suppressed oscillation signal again when step S118 is performed. As shown in fig. 9, a waveform (1) is a waveform of the first ultrasonic wave, and a waveform (2) is an oscillation signal waveform when oscillation suppression is not performed; the waveform (4) is an oscillation signal waveform subjected to oscillation suppression.

The present application also provides an ultrasonic ranging apparatus 10 for performing the ultrasonic ranging method as in the above embodiments. As shown in fig. 10, the ultrasonic ranging apparatus 10 includes a controller 101, and a first transmitting circuit 110, a first detecting circuit 120, a second transmitting circuit 130, and a second detecting circuit 140 connected to the controller 101.

Specifically, the first transmitting circuit 110 is configured to transmit a first ultrasonic wave at a preset number of pulses and a first frequency,

the first detection circuit 120 is configured to acquire a first echo.

The second transmitting circuit 130 is configured to transmit the second ultrasonic wave at a preset number of pulses and a second frequency.

The second detection circuit 140 is configured to acquire a second echo.

The controller 101 is connected to the first transmitting circuit 110, the first detecting circuit 120, the second transmitting circuit 130 and the second detecting circuit 140, and the controller 101 has a pre-stored preset number of pulses, a pre-stored first frequency and a pre-stored second frequency, so as to control the first transmitting circuit 110 to transmit the first ultrasonic wave and control the second transmitting circuit 130 to transmit the second ultrasonic wave.

The controller 101 is configured to: and calculating a time difference between the sending time of the first ultrasonic wave and the receiving time of the first echo to obtain a first duration. And obtaining a second duration by a time difference between the sending time of the second ultrasonic wave and the receiving time of the second echo. Meanwhile, the controller 101 is further configured to: and judging whether the first duration is the same as the second duration, if so, reducing the number of preset pulses, and retransmitting the first ultrasonic wave and the second ultrasonic wave to obtain a first echo and a second echo until the first duration is equal to the second duration. And when the first duration and the second duration are the same, calculating the distance to be measured according to the first duration and the first frequency.

The ultrasonic ranging apparatus 10 can perform the ultrasonic ranging method as in the above embodiments. This ultrasonic ranging device 10 through reducing the pulse number step by step, can reduce the measurement blind area of first ultrasonic wave and second ultrasonic wave to reduce ultrasonic ranging device 10's measurement blind area.

In one embodiment, as shown in fig. 11, the ultrasonic ranging apparatus 10 of the present application further includes a third transmitting circuit 150 and a third detecting circuit 160.

Specifically, the third transmitting circuit 150 is configured to transmit the first ultrasonic wave at a preset number of pulses and at a first frequency.

The third detection circuit 160 is configured to acquire a first echo.

At this time, the controller 101 is connected to the third transmission circuit 150 and the third detection circuit 160. The controller 101 has a prestored third frequency to control the third transmitting circuit 150 to transmit the third ultrasonic wave.

The controller 101 is further configured to: calculating a time difference value between the sending time of the third ultrasonic wave and the receiving time of the third echo to obtain a third time length; and if the third duration is different from the first duration and the second duration, reducing the number of preset pulses, and repeatedly executing the steps until the third duration is equal to the first duration and the second duration.

In one embodiment, as shown in fig. 12, the first transmitting circuit 110, the second transmitting circuit 130 and the third transmitting circuit 150 of the ultrasonic ranging apparatus 10 of the present application respectively include a digital-to-analog converter and an ultrasonic transmitter.

Specifically, the first transmission circuit 110 includes a digital-to-analog converter and an ultrasonic transmitter. The digital-to-analog converter is connected to the controller 101, and is configured to acquire a transmission digital signal sent from the controller 101 and convert the transmission digital signal into an analog signal. The ultrasonic transmitter is connected with the digital-to-analog converter and is configured to transmit the first ultrasonic wave or the second ultrasonic wave according to the analog signal.

Further, as shown in fig. 13, the first transmission circuit 110 further includes a gain control circuit and an oscillation suppression circuit.

Specifically, the gain control circuit is connected between the digital-to-analog converter and the ultrasonic transmitter and configured to amplify the amplitude of the analog signal by a preset gain factor. At this time, the controller 101 is configured to: and if the first time length is different from the second time length, reducing the number of the preset pulses, increasing the preset gain times, and re-sending the first ultrasonic wave and the second ultrasonic wave to obtain a first echo and a second echo until the first time length is equal to the second time length.

The oscillation suppression circuit is connected between the gain control circuit and the ultrasonic transmitter, and configured to suppress an oscillation signal of the analog signal.

Similarly, the second transmission circuit 130 includes a digital-to-analog converter and an ultrasonic transmitter, and further includes a gain control circuit and an oscillation suppression circuit. The third transmission circuit 150 also includes a digital-to-analog converter and an ultrasonic transmitter, and further includes a gain control circuit and an oscillation suppression circuit. No further description is given.

In one embodiment, the first detection circuit 120 of the ultrasonic ranging device 10 of the present application includes an amplifier, an analog-to-digital converter, a digital signal processor, and an echo detection circuit.

Specifically, the amplifier is configured to receive the first echo, amplify the first echo according to a certain ratio, and output the amplified first echo. At this time, the first echo is an analog signal. The analog-to-digital converter is connected with the amplifier and used for acquiring the analog signal output by the amplifier and converting the amplified first echo, namely the analog signal, into a digital signal. The digital signal processor is connected with the analog-to-digital converter and used for acquiring the digital signal output by the analog-to-digital converter and filtering the digital signal. The echo detection circuit is used for verifying the filtered digital signal so as to judge whether the filtered digital signal is a digital signal corresponding to the first echo. The echo detection circuit is further connected to the controller 101, so that the controller 101 starts the calculation of the first duration and the subsequent determination after the echo detection circuit confirms the first echo.

Generally, the echo detection circuit may extract the frequency and the number of pulses in the acquired digital signal, and compare the extracted frequency and the number of pulses with the frequency and the number of pulses of the first ultrasonic wave, so as to determine whether the acquired digital signal is a digital signal corresponding to the first echo.

Further, the second detection circuit 140 may also include an amplifier, an analog-to-digital converter, a digital signal processor, and an echo detection circuit; the third detection circuit 160 may also include an amplifier, an analog-to-digital converter, a digital signal processor, and an echo detection circuit. And will not be described in detail.

All possible combinations of the technical features of the above embodiments may not be described for the sake of brevity, but should be considered as within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. An ultrasonic ranging method, comprising:

sending a first ultrasonic wave, a second ultrasonic wave and a third ultrasonic wave in a preset pulse number, wherein the first ultrasonic wave has a first frequency, the second ultrasonic wave has a second frequency, the third ultrasonic wave has a third frequency, the first frequency is higher than the second frequency, and the third frequency is lower than the second frequency;

acquiring a first echo corresponding to the first ultrasonic wave, a second echo corresponding to the second ultrasonic wave and a third echo corresponding to the third ultrasonic wave;

calculating a time difference between the sending time of the first ultrasonic wave and the receiving time of the first echo to obtain a first duration; obtaining a second duration according to a time difference between the sending time of the second ultrasonic wave and the receiving time of the second echo; and a time difference between the sending time of the third ultrasonic wave and the receiving time of the third echo to obtain a third duration;

if the first duration is different from the second duration, reducing the number of the preset pulses, and repeatedly executing the steps until the first duration is equal to the second duration;

if the third time length is different from the first time length and the second time length, reducing the number of the preset pulses, and repeatedly executing the steps until the third time length is equal to the first time length and the second time length;

2. The ultrasonic ranging method according to claim 1, wherein before calculating the distance to be measured according to the first duration and the first frequency, the method further comprises:

judging whether the first time length, the second time length and the third time length are equal or not;

and if the first time length is equal to the second time length, calculating the distance to be measured according to the first time length and the first frequency.

3. The ultrasonic ranging method according to claim 1, wherein the transmitting the first ultrasonic wave and the second ultrasonic wave in a preset number of pulses comprises:

converting the transmit digital signal to an analog signal;

and sending the first ultrasonic wave or the second ultrasonic wave according to the analog signal.

4. The ultrasonic ranging method according to claim 3, further comprising, before the transmitting the first ultrasonic wave or the second ultrasonic wave according to the analog signal:

and amplifying the amplitude of the analog signal by a preset gain factor.

5. The ultrasonic ranging method according to claim 4, wherein if the first duration is different from the second duration; the repeatedly executing the above steps until the first duration is equal to the second duration further includes:

and increasing the preset gain multiple.

6. The ultrasonic ranging method according to claim 3, further comprising, before the transmitting the first ultrasonic wave or the second ultrasonic wave according to the analog signal:

and suppressing an oscillation signal of the analog signal.

7. An ultrasonic ranging device, comprising:

a first detection circuit configured to acquire a first echo;

a second detection circuit configured to acquire a second echo;

a third transmitting circuit configured to transmit a third ultrasonic wave at a preset number of pulses and a third frequency;

a third detection circuit configured to acquire a third echo;

a controller connected to the first transmitting circuit, the first detecting circuit, the second transmitting circuit, the second detecting circuit, the third transmitting circuit, and the third detecting circuit, the controller having a preset number of pulses and the first frequency, the second frequency, and the third frequency to control the first transmitting circuit to transmit the first ultrasonic wave, the second transmitting circuit to transmit the second ultrasonic wave, and the third transmitting circuit to transmit the third ultrasonic wave;

the controller is configured to: calculating a time difference between the sending time of the first ultrasonic wave and the receiving time of the first echo to obtain a first duration; obtaining a second duration by a time difference between the sending time of the second ultrasonic wave and the receiving time of the second echo; and a time difference between the sending time of the third ultrasonic wave and the receiving time of the third echo to obtain a third duration; if the first duration is different from the second duration, reducing the number of the preset pulses, and retransmitting the first ultrasonic wave and the second ultrasonic wave to obtain the first echo and the second echo until the first duration is equal to the second duration; if the third time length is different from the first time length and the second time length, reducing the number of the preset pulses, and re-sending the first ultrasonic wave, the second ultrasonic wave and the third ultrasonic wave to obtain the first echo, the second echo and the third echo until the third time length is equal to the first time length and the second time length; and calculating the distance to be measured according to the first duration and the first frequency.

8. The ultrasonic ranging device according to claim 7, further comprising:

the controller is configured to: judging whether the first time length, the second time length and the third time length are equal or not; and if the first time length is equal to the second time length, calculating the distance to be measured according to the first time length and the first frequency.

9. The ultrasonic ranging device according to claim 7, wherein the first transmission circuit or the second transmission circuit comprises:

the digital-to-analog converter is connected with the controller and is configured to acquire a sending digital signal sent by the controller and convert the sending digital signal into an analog signal;

an ultrasonic transmitter connected to the digital-to-analog converter and configured to transmit the first ultrasonic wave or the second ultrasonic wave according to the analog signal.

10. The ultrasonic ranging device according to claim 9, wherein the first transmission circuit or the second transmission circuit further comprises: