CN115932810A - Echo signal detection method, chip and device of ultrasonic sensor - Google Patents

Echo signal detection method, chip and device of ultrasonic sensor Download PDF

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Publication number
CN115932810A
CN115932810A CN202211667300.6A CN202211667300A CN115932810A CN 115932810 A CN115932810 A CN 115932810A CN 202211667300 A CN202211667300 A CN 202211667300A CN 115932810 A CN115932810 A CN 115932810A
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signal
comparison
reference signal
frequency
amplitude
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苏晶
康泽华
杨大庆
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Chengdu Jihai Technology Co ltd
Shanghai Jihaiyingxin Technology Co ltd
Zhuhai Geehy Semiconductor Co Ltd
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Chengdu Jihai Technology Co ltd
Shanghai Jihaiyingxin Technology Co ltd
Zhuhai Geehy Semiconductor Co Ltd
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Priority to CN202211667300.6A priority Critical patent/CN115932810A/en
Publication of CN115932810A publication Critical patent/CN115932810A/en
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    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
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Abstract

The embodiment of the application provides an echo signal detection method, a chip and a device of an ultrasonic sensor. The method comprises the steps of periodically reading a first point signal and a second point signal of an echo signal according to a preset reading frequency, wherein the first point signal is used as a reference signal, and the second point signal is used as a comparison signal; determining whether the reference signal and the comparison signal are target signals or not based on the amplitude information of the reference signal and the comparison signal; when the reference signal and the comparison signal are target signals, updating the preset reading frequency to a first frequency, and updating the number of the target signals; when the reference signal and the comparison signal are not the target signals, updating the preset reading frequency to a second frequency, and recovering or maintaining the number of the target signals to an initial value; the first frequency is not less than the second frequency; and judging whether the target echo signal appears or not based on whether the number of the target signals is larger than a preset value or not. To improve the efficiency of echo detection.

Description

Echo signal detection method, chip and device of ultrasonic sensor
Technical Field
The application relates to the technical field of ultrasonic waves, in particular to an echo signal detection method of an ultrasonic sensor, an ultrasonic sensor chip and an automobile ultrasonic radar device.
Background
For better ranging, backing or parking assistance, backing assistance devices are usually installed in vehicles. The reversing aid includes an ultrasonic transmitter and an ultrasonic receiver, wherein the ultrasonic transmitter and the ultrasonic receiver may be respectively integrated into one ultrasonic transducer, or the transmitter and the receiver may be respectively disposed. When the transmitted ultrasonic wave signal is reflected by an obstacle or an object near the vehicle, an echo signal may be detected in the received signal, so that the distance between the obstacles may be calculated using the time difference between the transmission of the ultrasonic wave and the reception of the echo signal.
In some techniques, the method of detecting the echo signal is to wait until all the reflected signals are received, process the received signal, and compare the processed received signal with a threshold value to determine whether the received signal is an echo signal. The method needs to process all received signals after all reflected signals are received, and determines whether the received signals are echo signals, so that the processing speed is low, and the echo detection efficiency is reduced. Alternatively, in some technologies, a peak value extraction process may be performed on the received signal, and the extracted peak value is compared with a preset threshold value, so as to determine whether the received signal is an echo signal. The method needs to extract the peak value of the received signal, is complex to realize, can judge the echo signal after the reflected signal is received, and has low detection speed and low efficiency.
Disclosure of Invention
In view of this, the present application provides an echo signal detection method for an ultrasonic sensor, an ultrasonic sensor chip, and an automotive ultrasonic radar apparatus, so as to solve the problem of low echo detection efficiency in the prior art.
In a first aspect, an embodiment of the present application provides an echo signal detection method for an ultrasonic sensor, including:
periodically reading a first point signal and a second point signal of an echo signal according to a preset reading frequency, wherein the first point signal is used as a reference signal, the second point signal is used as a comparison signal, and the reading time interval between the reference signal and the comparison signal is preset;
determining whether the reference signal and the comparison signal are target signals based on amplitude information of the reference signal and the comparison signal; when the reference signal and the comparison signal are target signals, updating the preset reading frequency to a first frequency, and updating the number of the target signals; when the reference signal and the comparison signal are not target signals, updating the preset reading frequency to a second frequency, and recovering or maintaining the number of the target signals to an initial value; the first frequency is not less than the second frequency;
and judging whether a target echo signal appears or not based on whether the number of the target signals is larger than a preset value or not.
In a second aspect, an embodiment of the present application provides an ultrasonic sensor chip, including: the device comprises a sampling circuit, a filter circuit and a reading processing circuit;
the sampling circuit is coupled to the ultrasonic transducer to sample the echo signal;
the filtering circuit is electrically connected with the sampling circuit and is used for filtering the echo signal input by the sampling circuit to output an echo signal with a preset frequency;
the reading processing circuit is electrically connected with the filter circuit and is used for judging whether the input echo signal with the preset frequency is a target echo signal or not;
the reading processing circuit comprises a reading module, a comparison module, a control module and a judgment module;
the reading module is electrically connected with the filter circuit and is used for periodically reading a first point signal and a second point signal of the echo signal with the preset frequency according to a preset reading frequency, the first point signal is used as a reference signal, the second point signal is used as a comparison signal, and the reading time interval between the reference signal and the comparison signal is preset time;
the comparison module is electrically connected with the reading module and is used for receiving the amplitude information of the reference signal and the comparison signal input by the reading module and determining whether the reference signal and the comparison signal are target signals;
the control module is electrically connected with the comparison module and the read module and used for receiving a comparison result of the comparison module, and updating the preset reading frequency of the read module to a first frequency and updating the number of the target signals when the reference signal and the comparison signal are target signals; when the reference signal and the comparison signal are not target signals, updating the preset reading frequency of the reading module to a second frequency, and recovering or maintaining the number of the target signals to an initial value; the first frequency is not less than the second frequency;
the judging module is electrically connected with the control module, reads the quantity data of the target signals of the control module, and judges that target echo signals appear if the quantity of the target signals is larger than a preset value.
In a third aspect, an embodiment of the present application provides an automotive ultrasonic radar apparatus, including: comprising an ultrasonic transducer and the ultrasonic sensor chip of the second aspect;
the ultrasonic sensor chip is electrically connected with the ultrasonic transducer and used for judging whether the echo signal received by the ultrasonic transducer is a target echo signal.
By adopting the scheme provided by the embodiment of the application, the first point signal and the second point signal of the echo signal are periodically read according to the preset reading interval, the first point signal is used as a reference signal, the second point signal is used as a comparison signal, and the reading time interval between the reference signal and the comparison signal is preset time; determining whether the reference signal and the comparison signal are target signals or not based on the amplitude information of the reference signal and the comparison signal, and if the reference signal and the comparison signal are the target signals, updating the preset reading frequency to a first frequency and updating the number of the target signals; when the reference signal and the comparison signal are not the target signals, updating the preset reading frequency to a second frequency, and recovering or maintaining the number of the target signals to an initial value; the first frequency is not less than the second frequency; and judging whether the target echo signal appears or not based on whether the number of the target signals is larger than a preset value or not. That is, in the embodiment of the present application, the target echo signal is determined by periodically reading the reference signal and the comparison signal, and the target echo signal is determined without waiting for the reflected signal to be completely received, so that the read data amount can be greatly reduced, and the hardware overhead can be reduced. In addition, corresponding threshold judgment is not required to be carried out after all the transmitting signals are received or the peak values are extracted, the processing speed of echo judgment is increased, and therefore the efficiency of echo detection is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an automotive ultrasonic radar apparatus according to an embodiment of the present disclosure;
fig. 2a is a schematic structural diagram of an ultrasonic sensor chip according to an embodiment of the present disclosure;
fig. 2b is a schematic structural diagram of another ultrasonic sensor chip provided in an embodiment of the present application;
fig. 3 is a schematic flowchart of an echo signal detection method of an ultrasonic sensor chip according to an embodiment of the present disclosure;
fig. 4 is a schematic scene diagram of an echo signal detection method of an ultrasonic sensor chip according to an embodiment of the present disclosure;
fig. 5 is a schematic view of a scene of another echo signal detection method of an ultrasonic sensor chip according to an embodiment of the present disclosure;
fig. 6a is a schematic view of a scene of another echo signal detection method of an ultrasonic sensor chip according to an embodiment of the present disclosure;
fig. 6b is a schematic view of a scene of another echo signal detection method of an ultrasonic sensor chip according to an embodiment of the present disclosure;
fig. 7a is a schematic view of a scene of another echo signal detection method of an ultrasonic sensor chip according to an embodiment of the present disclosure;
fig. 7b is a schematic view of a scene of another echo signal detection method for an ultrasonic sensor chip according to an embodiment of the present application;
fig. 8 is a schematic structural diagram of another ultrasonic sensor chip provided in an embodiment of the present application;
fig. 9a is a schematic structural diagram of another ultrasonic sensor chip provided in an embodiment of the present application;
fig. 9b is a schematic structural diagram of another ultrasonic sensor chip provided in an embodiment of the present application;
FIG. 10 is a schematic structural diagram of another ultrasonic radar apparatus for an automobile according to an embodiment of the present application;
fig. 11 is a schematic structural diagram of another automotive ultrasonic radar apparatus according to an embodiment of the present application.
Detailed Description
For better understanding of the technical solutions of the present application, the following detailed descriptions of the embodiments of the present application are provided with reference to the accompanying drawings.
It should be understood that the embodiments described are only a few embodiments of the present application, and not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.
The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be understood that the term "and/or" as used herein is merely one type of associative relationship that describes an associated object, meaning that three types of relationships may exist, e.g., A and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.
Before specifically describing the embodiments of the present application, terms applied or likely to be applied to the embodiments of the present application will be explained first.
ADC: an Analog-to-digital converter (A/D or AtoD) is a device that converts a continuously changing Analog signal into a discrete digital signal.
An ECU: an Electronic Control Unit (Electronic Control Unit), which is also called a driving computer, a vehicle-mounted computer, etc. It is similar to common computer and consists of micro processing unit (MCU), memory (ROM, RAM), I/O interface, A/D converter, shaping and driving IC.
PCB: the Printed Circuit Board (hereinafter, also referred to as "Printed Circuit Board") is an important electronic component, a support for electronic components, and a carrier for electrically interconnecting electronic components.
FPC: a Flexible Printed Circuit (FPC) is a Flexible Printed Circuit board which is made of polyimide or polyester film as a base material and has high reliability and excellent performance.
CAN (Controller Area Network) is the abbreviation of Controller Area Network.
LIN (Local Interconnect Network). The LIN has the main function of providing auxiliary functions for the CAN bus network, and the LIN bus is a common A-type network protocol at present.
PTP: (Point-to-Point) Point-to-Point is a link layer protocol designed for simple links that transport packets between peer units. Such links provide full duplex operation and deliver packets in sequence.
In some techniques, the method of detecting the echo signal is to wait until all the reflected signals are received, process the received signal, and compare the processed received signal with a threshold value to determine whether the received signal is an echo signal. The method needs to process all received signals after all reflected signals are received, and determines whether the received signals are echo signals, so that the processing speed is low, and the echo detection efficiency is reduced. Alternatively, in some technologies, a peak value extraction process may be performed on the received signal, and the extracted peak value is compared with a preset threshold value, so as to determine whether the received signal is an echo signal. The method needs to extract the peak value of the received signal, is complex to realize, can judge the echo signal after the reflected signal is received, and has low detection speed and low efficiency.
In order to solve the above problem, an embodiment of the present invention provides an echo signal detection method for an ultrasonic sensor, an ultrasonic sensor chip, and an automotive ultrasonic radar apparatus, where a first point signal and a second point signal of an echo signal are periodically read at a preset reading interval, the first point signal is used as a reference signal, the second point signal is used as a comparison signal, and a reading time interval between the reference signal and the comparison signal is preset time; determining whether the reference signal and the comparison signal are target signals or not based on the amplitude information of the reference signal and the comparison signal, and if the reference signal and the comparison signal are the target signals, updating the preset reading frequency to a first frequency and updating the number of the target signals; when the reference signal and the comparison signal are not the target signals, updating the preset reading frequency to a second frequency, and recovering or maintaining the number of the target signals to or at an initial value; the first frequency is not less than the second frequency; and judging whether the target echo signal appears or not based on whether the number of the target signals is larger than a preset value or not. That is, in the embodiment of the present application, the target echo signal is determined by periodically reading the reference signal and the comparison signal, and it is not necessary to determine the target echo signal after the reflected signal is completely received, so that the amount of read data can be greatly reduced, and the overhead of hardware can be reduced. In addition, corresponding threshold judgment is not required to be carried out after all the transmitting signals are received or after peak values are extracted, the processing speed of echo judgment is increased, and therefore the efficiency of echo detection is improved. . The details will be described below.
Referring to fig. 1, a schematic structural diagram of an automotive ultrasonic radar apparatus provided in an embodiment of the present application is shown. The ultrasonic radar apparatus for an automobile includes a substrate 10, an ultrasonic sensor chip 20, an ultrasonic wave transmitting sensor 30, and an ultrasonic wave receiving sensor 40. In some embodiments, the substrate 10 may be a PCB board or an FPC (Flexible Printed Circuit) board. The ultrasonic sensor chip 20 is provided on the substrate 10. The ultrasonic sensor chip 20 includes a body 201, an IC (Integrated Circuit) Circuit 202 located inside the body, and a pin located outside the body 201 and electrically connected to the IC Circuit 202. The pins include at least one first pin 2031, at least one second pin 2032, and at least one third pin 2033. The IC circuit 202 is connected to the ultrasonic transmission sensor 30 through at least one first pin 2031. The IC circuit 202 is electrically connected to a main control ECU or a microprocessor chip in the vehicle through at least one second pin 2032. In some embodiments, the IC circuit 202 is electrically connected to a microprocessor chip in the vehicle via at least one second pin 2032 in a CAN bus mode or a LIN mode or a PTP mode. The IC circuit 202 is connected to the ultrasonic wave receiving sensor 40 through at least one third pin 2033.
In some embodiments, the ultrasonic transmitting sensor 30 and the ultrasonic receiving sensor 40 may be integrated into one sensor, that is, one ultrasonic sensor can transmit and receive ultrasonic signals. That is, one ultrasonic sensor may serve as both an ultrasonic wave transmitting sensor and an ultrasonic wave receiving sensor, and then the third pin 2033 is identical to the first pin 2031.
Referring to fig. 2a, a schematic structural diagram of an ultrasonic sensor chip provided in an embodiment of the present application is shown. The IC circuit 202 in the ultrasonic sensor chip 20 includes a front-end circuit 2021, a main control circuit 2022, a driving circuit 2023, a reading processing circuit 2024, and a timer 2025. After the main control circuit 2022 of the ultrasonic sensor chip 20 receives the trigger signal from an upper computer, such as a main control ECU or a microprocessor chip of an automobile, the main control circuit 2022 controls the driving circuit 2023 to generate an ultrasonic excitation signal, where the ultrasonic excitation signal is used to drive the ultrasonic emission sensor 30 to emit an ultrasonic wave. After the ultrasonic wave transmitting sensor 30 transmits the ultrasonic wave signal, the ultrasonic wave signal hits an obstacle and is reflected. The ultrasonic wave receiving sensor 40 starts receiving the reflected ultrasonic wave signal after the ultrasonic wave transmitting sensor 30 transmits the ultrasonic wave signal. After the ultrasonic wave receiving sensor 40 receives the transmitted ultrasonic wave signal, the received ultrasonic wave signal may be transmitted to the front-end circuit 2021 in the IC circuit 202. Since the ultrasonic receiving sensor 40 is constantly receiving ultrasonic signals in the environment, however, the received ultrasonic signals include interference signals such as environmental interference signals and ultrasonic signals emitted by other ultrasonic emitting sensors, and therefore, after the front-end circuit 2021 receives the emitted ultrasonic signals, it is necessary to sample, filter, and amplify the received ultrasonic signals. The front-end circuit 2021 can filter out the ultrasonic signal within the preset frequency range by improving the filtering precision, and can also retain the ultrasonic signal within the preset frequency range only by implementing the function of a high-pass, low-pass or band-pass filter on the front-end circuit. The preset frequency range includes the frequency of the ultrasonic signal emitted by the ultrasonic emission sensor 30. The front-end circuit 2021 transmits the processed ultrasonic signal to the reading processing circuit 2024. The read processing circuit 2024 reads and processes the received ultrasonic signal to detect whether or not the received ultrasonic signal is a target echo signal. When it is detected that the received ultrasonic signal is the target echo signal, it is determined that the echo signal emitted from the ultrasonic wave transmitting sensor 30 and emitted from the obstacle has been received. The timer 2025 starts counting after the driving circuit 2023 finishes transmitting the excitation signal, and stops counting when the reading processing circuit determines that the target echo signal is received. The main control circuit 2022 calculates the distance to the obstacle according to the relationship between the time counted by the timer and the propagation speed of the ultrasonic signal; after obtaining the distance information, the main control circuit 2022 sends the distance information to a main control ECU or a microprocessor chip in the automobile. After the main control ECU or the micro-processing chip in the automobile receives the distance information, whether prompt information is sent or not can be determined according to the distance information. Of course, the distance calculating function may also be executed by the microprocessor chip, and after the reading processing circuit 2024 detects the target echo signal, an indication signal indicating that the echo signal is received is sent to the microprocessor chip, and the time from when the trigger signal is sent to when the indication signal is received by the microprocessor chip is used as the time reference for calculating the obstacle distance. Meanwhile, the timer in the main control circuit is not used for calculating the distance, but is used for the reading processing circuit 2024 to perform the echo signal judgment, and the timer may be disposed in the micro processing chip, or of course, the main control circuit may not be provided with a corresponding timer, which is specifically described below.
In some embodiments, to reduce the size of the ultrasonic sensor chip, the timer 2025 and the read processing circuit 2024 may be integrated in the main control circuit 2022. In the embodiment of the present application and fig. 2a, the timer 2025 and the read processing circuit 2024 are integrated in the main control circuit 2022 as an example. Moreover, the circuit part of the main control circuit 2022 for driving the circuit may be disposed in a different circuit from the part for processing the echo signal, and the specific disposition is not limited.
In some embodiments, amplifiers and filters are integrated within the front-end circuit 2021.
In some embodiments, when the read processing circuit 2024 can only process digital signals, an analog-to-digital converter ADC 2026 is further disposed in the IC circuit 202 of the ultrasonic sensor chip, as shown in fig. 2 b. The ADC 2026 is disposed between the front-end circuit 2021 and the reading processing circuit 2024, and the ADC 2026 converts the ultrasonic signal transmitted by the front-end circuit 2021 from an analog signal to a digital signal and transmits the digital signal to the reading processing circuit 2024.
In some embodiments, if the filtering precision in the front-end circuit 2021 is low and cannot filter out the ultrasonic signal in the preset frequency range, a matched filter 2027 (which may also be a high-precision digital filter) is further disposed in the IC circuit 202 of the ultrasonic sensor chip, as shown in fig. 2 b. The matched filter 2027 is disposed between the ADC 2026 and the read processing circuit 2024, and the ultrasonic signal of the digital signal converted by the ADC can be subjected to matched filtering processing by the matched filter 2027, so that the ultrasonic signal in the preset frequency range is detected. The detected ultrasonic signal is transmitted to the reading processing circuit 2024. It is understood that the front-end circuit 2021 is not required, the ADC 2026 performs ADC conversion on the echo signal received by the third pin 2033, the converted signal is further subjected to filtering processing, and the processed signal is input to the read processing circuit 2024.
Referring to fig. 3, a schematic flowchart of an echo signal detection method according to an embodiment of the present application is shown. This method is applied to the ultrasonic sensor chip shown in fig. 2a and 2 b. As shown in fig. 3, the method includes:
step S301, periodically reading a first point signal and a second point signal of the echo signal at a preset reading interval, and using the first point signal as a reference signal and the second point signal as a comparison signal.
The reading time interval between the reference signal and the comparison signal is preset.
In the embodiment of the present application, after receiving the reflected ultrasonic signal, after filtering to find the ultrasonic signal within the preset frequency range, the ultrasonic signal may be an environmental interference signal or an ultrasonic signal emitted by another ultrasonic emission sensor, and therefore, the received ultrasonic signal needs to be further detected to determine whether the received ultrasonic signal is an echo signal required by the ultrasonic sensor chip. Based on this, the ultrasonic sensor chip may periodically perform signal reading on the received ultrasonic signal, that is, the echo signal, according to a preset reading frequency, to obtain a first point signal and a second point signal, where the first point signal is used as a reference signal, and the second point signal is used as a comparison signal. The reading time of the reference signal and the reading time of the comparison signal are separated by a preset time. That is, when the ultrasonic sensor chip periodically reads the reference signal and the comparison signal according to the preset reading frequency, the reference signal is read first, and after the reference signal is read, the comparison signal is read at a preset time interval.
In some embodiments, the ultrasonic sensor chip may amplify, filter, and the like the ultrasonic signal received by the ultrasonic receiving sensor, so as to obtain an echo signal within a preset frequency range. Wherein, the preset frequency range comprises the frequency of the ultrasonic signal emitted by the ultrasonic emission sensor. The ultrasonic sensor chip needs to detect whether the echo signal in the preset frequency range is the required echo signal, so the ultrasonic sensor chip periodically reads the reference signal and the comparison signal from the echo signal in the preset frequency range according to the preset reading frequency.
It should be noted that the preset reading frequency is set before reading the reference signal and the comparison signal. The preset reading frequency may be a fixed frequency value, so that the ultrasonic sensor chip directly uses the reading frequency as a reading period to read the periodic reference signal and the comparison signal. Therefore, related implementation circuits in the ultrasonic sensor chip can be simplified, and the complexity of the ultrasonic sensor chip is reduced.
In some embodiments, the predetermined read frequency may also be adjusted in real time. The ultrasonic sensor chip can set the reading frequency according to whether the reference signal and the comparison signal are the target signals. For example, the reading frequency may be set to a first frequency when the reference signal and the comparison signal are the target signals, and set to a second frequency when the reference signal and the comparison signal are not the target signals, and the first frequency is greater than or equal to the second frequency.
Step S302, determining whether the reference signal and the comparison signal are target signals or not based on the amplitude information of the reference signal and the comparison signal; when the reference signal and the comparison signal are target signals, updating the preset reading frequency to a first frequency, and updating the number of the target signals; when the reference signal and the comparison signal are not the target signals, the preset reading frequency is updated to the second frequency, and the number of the target signals is restored to or maintained at the initial value.
The target signal is an ultrasonic signal whose amplitude information is not less than a corresponding threshold value. The first frequency is not less than the second frequency.
In the embodiment of the present application, after the ultrasonic sensor chip reads the reference signal and the comparison signal each time, it needs to detect whether the read reference signal and the comparison signal are echo signals required by the ultrasonic sensor chip. After the reference signal and the comparison signal are read in the current period, the ultrasonic sensor chip may detect whether the reference signal and the comparison signal read in the current period are the target signals. From the start of oscillation to the normal oscillation and to the end of oscillation of the ultrasonic transducer, the ultrasonic wave tends to have a tendency from a small amplitude to a large amplitude and then from the large amplitude to the small amplitude, as shown in fig. 4. For accuracy, a wave reaching a certain threshold will be used as a reference for receiving a target echo signal. In the received echo signal, the same frequency wave as the received echo signal also contains other interference waves, and the amplitude of the interference waves is generally small. At this time, the echo signal with a smaller amplitude cannot be used as a basis for determining the target echo signal, that is, the amplitude of the target echo signal is greater than a certain threshold. Based on this, the ultrasonic sensor chip detects whether the amplitude information of the reference signal and the comparison signal read in the current period is not less than the threshold corresponding to the current period, so as to determine whether the reference signal and the comparison signal are the target signals. And if the amplitude information of the reference signal and the comparison signal read in the current period is not less than the threshold corresponding to the current period, determining that the reference signal and the comparison signal are target signals. And if the amplitude information of the reference signal and the comparison signal read in the current period is smaller than the threshold corresponding to the current period, determining that the reference signal and the comparison signal are not the target signal.
In order to more accurately determine whether the reference signal and the comparison signal read by the ultrasonic sensor chip are echo signals required by the ultrasonic sensor chip, when the reference signal and the comparison signal of a plurality of reading periods continuously appear as target signals, the read reference signal and the comparison signal are echo signals required by the ultrasonic sensor chip, that is, the target echo signals, need to be determined. Therefore, when the ultrasonic sensor chip determines that the read reference signal and the comparison signal are target signals, the number of target signals is updated by adding 1 to the number of target signals.
Or, when the ultrasonic sensor chip determines that the reference signal and the comparison signal are not the target signals, it indicates that the reference signal and the comparison signal read in the current cycle are not the target echo signals required by the ultrasonic sensor chip. Since the ultrasonic excitation signal is continuous and the target echo signal should also be continuous, when the reference signal and the comparison signal read in the current period are not the target echo signal required by the ultrasonic sensor chip, the reference signal and the comparison signal read in the reading period before the current period are also not the target echo signal required by the ultrasonic sensor chip. That is, the ultrasonic signal currently received by the ultrasonic sensor chip is not the required target echo signal, and based on this, the number of the target signals needs to be restored or maintained to an initial value, such as zero clearing, or other initial values when the reference signal and the comparison signal of the ultrasonic sensor chip are not the target signals. For example, if 2 target signals are continuously present, the number of target signals is 2, and when the 3 rd target signal is present, the number of target signals is 3; if the immediately following signal is not the target signal, the number of target signals is restored to 0. If the signal present is not the target signal, the number of target signals remains at the initial value of 0.
In some embodiments, in a reading period before the current period, even if it is determined that the read reference signal and the comparison signal are target signals, since the reference signal and the comparison signal read in the current period are not target signals, it indicates that the ultrasonic signal currently received by the ultrasonic sensor chip is not a required target echo signal, and therefore, the ultrasonic sensor chip needs to zero the number of the target signals and discard all the reference signals and the comparison signals that have been currently read.
In order to reduce the hardware overhead and increase the accuracy of the determination of the target echo signal, the ultrasonic sensor chip may set the reading frequency according to whether the reference signal and the comparison signal are the target signals. When the reference signal and the comparison signal are the target signals, the reading frequency may be set to the first frequency, that is, the reading may be performed at the first frequency cycle when the reference signal and the comparison signal are performed next time. When the reference signal and the comparison signal are not the target signal, the reading frequency is set to be the second frequency, and the first frequency is greater than or equal to the second frequency, namely, the reading is performed in the second frequency period when the reference signal and the comparison signal are performed next time. Therefore, the reading frequency can be adjusted in real time, when the reference signal and the comparison signal are target signals, the reading interval can be reduced, and the reading frequency is improved, so that whether the reference signal and the comparison signal are target echo signals or not is determined by reading more reference signals and comparison signals, and the accuracy of target echo signal detection is improved. When the reference signal and the comparison signal are not the target signal, the reading interval can be increased, the reading frequency can be reduced, the data amount to be read can be reduced, and the hardware overhead can be reduced.
The initial reading frequency can be a first frequency or a second frequency, preferably the first frequency, so as to improve the judgment accuracy of the short distance.
The ultrasonic sensor chip needs to detect whether the amplitude information of the reference signal and the comparison signal read in the current period is not less than the threshold corresponding to the current period, so as to determine whether the reference signal and the comparison signal are target signals. The threshold may be a magnitude threshold directly or a magnitude difference threshold. Since the amplitude of the read ultrasonic signal is larger for the same two read time instants in different read cycles, the amplitude difference between the two read signal points is also larger. Therefore, the amplitude information of the ultrasonic signal can be determined according to the magnitude of the amplitude difference. In the embodiment of the present application, when the amplitude difference is greater than the amplitude difference threshold, it indicates that the read amplitude information of the ultrasonic signal meets the amplitude requirement of the target echo signal. The threshold corresponding to the current period is an amplitude threshold or an amplitude difference threshold, and is related to whether the amplitude information of the reference signal is a preset reference value. When the amplitude information of the reference signal is the preset reference value, it is necessary to determine whether the reference signal and the comparison signal are the target signal according to the amplitude information of the comparison signal, and at this time, the threshold corresponding to the current period may be determined as the amplitude threshold. If the amplitude information of the reference signal is not the preset reference value, it is necessary to determine whether the reference signal and the comparison signal are the target signal according to the amplitude information of the reference signal and the comparison signal, and at this time, the threshold corresponding to the current period may be determined as the amplitude difference threshold. Therefore, when determining whether the reference signal and the comparison signal are the target signals, it is necessary to first determine whether the amplitude information of the reference signal is a preset reference value. At this time, as a possible implementation manner, determining whether the reference signal and the comparison signal are the target signal based on the amplitude information of the reference signal and the comparison signal includes:
detecting whether the amplitude information of the reference signal is a preset reference value or not; if the amplitude information of the reference signal is a preset reference value, determining an amplitude threshold corresponding to the current period; detecting whether the amplitude information of the comparison signal is not less than an amplitude threshold corresponding to the current period; and if the amplitude information of the comparison signal is not less than the amplitude threshold corresponding to the current period, determining the reference signal and the comparison signal as target signals.
In this embodiment, the ultrasonic sensor chip needs to detect whether the amplitude information of the reference signal is a preset reference value, and if the amplitude information of the reference signal is the preset reference value, it may be determined that the threshold corresponding to the current period is an amplitude threshold, and the amplitude information of the comparison signal may be compared with the amplitude threshold corresponding to the current period. At this time, the ultrasonic sensor chip may determine the amplitude threshold corresponding to the current period according to the reading time of the comparison signal at the current time or the current period or the reading time of the reference signal in the current period, or according to other times in the current period, and may further use the amplitude information read in the clock period as the amplitude threshold. The ultrasonic sensor chip detects whether the amplitude of the comparison signal is greater than or equal to the amplitude threshold of the current period. When the amplitude of the comparison signal is greater than or equal to the amplitude threshold corresponding to the current period, it indicates that the amplitude information of the reference signal and the comparison signal read in the current period meets the requirement of the amplitude of the required echo signal of the ultrasonic sensor chip, and the amplitude information can be determined as the target signal.
For convenience of implementation, the amplitude threshold value is set by taking a preset reference value as a reference. That is, the amplitude threshold is a threshold that varies from a preset reference value. Therefore, when the amplitude information of the reference signal is the preset reference value, whether the reference signal and the comparison signal read in the current period are the target signals or not can be determined directly according to the magnitude relation between the amplitude information of the comparison signal and the amplitude threshold corresponding to the current period.
It should be understood that the preset reference value is preset according to actual requirements. The preset reference value may be 0 v, or may be other values, which is not limited in the present application.
When determining whether the reference signal and the comparison signal are the target signal based on the amplitude information of the reference signal and the comparison signal, it is necessary to compare the amplitude information of the reference signal and the comparison signal with the corresponding threshold values. Therefore, when the ultrasonic sensor chip determines that the reference signal is the preset reference value and the amplitude threshold corresponding to the current period needs to be further determined, the determination may be performed in the following manner. That is, determining the amplitude threshold corresponding to the current period includes:
and determining the amplitude threshold value corresponding to the current period according to the time interval between the current time and the time of transmitting the ultrasonic signal.
Since the energy of the ultrasonic signal gradually decreases with time during the transmission process, the amplitude of the ultrasonic signal also gradually decreases. Therefore, in the embodiment of the present application, the amplitude threshold is different in each reading period, and the amplitude threshold decreases with the increase of time, and the amplitude is larger as the distance from the time of transmitting the ultrasonic signal is closer, and the amplitude threshold should be set to be larger at this time. Based on this, different amplitude thresholds may be set in advance for different time intervals from the time at which the ultrasonic signal is transmitted. For example, if the time interval from the time of transmitting the ultrasonic wave signal is within t1 second, the amplitude threshold is set to Vth1, if the time interval from the time of transmitting the ultrasonic wave signal is greater than t1 second and not greater than t2 second, the amplitude threshold is set to Vth2, if the time interval from the time of transmitting the ultrasonic wave signal is greater than t2 second and not greater than t3 second, and the like, the amplitude threshold is set to Vth3, where Vth1 is greater than Vth2, and Vth2 is greater than Vth3.
Since amplitude thresholds corresponding to different time intervals at which the ultrasonic signal is transmitted are set in advance. Therefore, the ultrasonic sensor chip may determine the time to transmit the ultrasonic signal first, in some embodiments, the ultrasonic sensor chip may trigger a timer to time when the ultrasonic signal is transmitted from the ultrasonic transmitting sensor, and the ultrasonic sensor chip may determine the time to transmit the ultrasonic signal directly from the timer. In some embodiments, the ultrasonic sensor chip may obtain the time at which the ultrasonic signal is emitted from the ultrasonic emission sensor. Of course, the ultrasonic sensor chip may also determine the time when the ultrasonic signal is transmitted by other means, which is not limited in this application. After the ultrasonic sensor chip determines the time for transmitting the ultrasonic signal, the amplitude threshold corresponding to the current period can be determined according to the time interval between the current time and the time for transmitting the ultrasonic signal.
In addition, a corresponding timer may not be provided, that is, a plurality of amplitude threshold values, which are time-related, may be stored in advance, as described above, but only amplitude threshold value information is stored in the storage module, and in comparison, threshold value information at different addresses in the storage module is read and input to the comparison module for comparison with a change in the clock. The method can save hardware circuits, simplify data processing flow and improve processing speed. At this time, determining the amplitude threshold corresponding to the current period includes: one of a plurality of amplitude thresholds is read according to a clock cycle.
That is, a plurality of preset amplitude threshold values are stored in the storage module, and the amplitude threshold values stored in the storage module correspond to different clock cycles, so that the amplitude threshold values in the storage module can be directly read along with the change of the clock cycles. The ultrasonic sensor chip can acquire a corresponding amplitude threshold according to the current clock cycle so as to judge whether the reference signal and the comparison signal are the target signals.
As a possible implementation manner, in the above process, the ultrasonic sensor chip needs to detect whether the amplitude information of the reference signal is a preset reference value, determine an amplitude difference threshold corresponding to the current period when the amplitude information of the reference signal is not the preset reference value, and determine an amplitude difference between the reference signal and the comparison signal based on the amplitude information of the reference signal, the amplitude information of the comparison signal, the reading time of the reference signal, and the reading time of the comparison signal; detecting whether the amplitude difference value is not less than an amplitude difference value threshold value; and when the amplitude difference value is not less than the amplitude difference value threshold value, determining the reference signal and the comparison signal as target signals.
When the ultrasonic sensor chip reads, the amplitude information of the read reference signal may not be the preset reference value, that is, when the ultrasonic sensor chip determines that the amplitude information of the reference signal is not the preset reference value, if the threshold corresponding to the current period is still determined as the amplitude threshold at this time, when the amplitude information of the comparison signal is directly used for comparison with the amplitude threshold, because the amplitude information of the reference signal is not the preset reference value, an error in a larger comparison result may exist, and the determination result is inaccurate. Therefore, in order to reduce the erroneous judgment, the threshold corresponding to the current period may be determined to be the amplitude difference threshold. At this time, the amplitude difference threshold corresponding to the current period may be determined according to the reading time of the comparison signal at the current time or the current period, the reading time of the reference signal in the current period, or other times in the current period. After the amplitude difference threshold of the current period is determined, the amplitude difference of the current period needs to be calculated. In this case, the ultrasonic sensor chip may calculate the amplitude change between the reference signal and the comparison signal based on the amplitude information of the reference signal, the amplitude information of the comparison signal, the reading time of the reference signal, and the reading time of the comparison signal. For example, Δ V = V 0 -V 0 ', wherein, V 0 Representing amplitude information of the comparison signal, V 0 ' denotes amplitude information of the reference signal, and Δ V is an amplitude change. And when the amplitude difference value is not smaller than the amplitude difference value threshold value, determining the reference signal and the comparison signal as target signals. Of course, the comparison between the magnitude difference and the magnitude difference threshold may be made in a number of ways, e.g. by a comparatorFormula tan theta = (V) 0 -V 0 ')/L, where tan theta represents the amplitude difference angle of the reference signal and the comparison signal, V 0 Representing amplitude information of the comparison signal, V 0 ' denotes amplitude information of the reference signal, and L denotes a time interval between the reference signal and the comparison signal. Comparing the calculated amplitude difference value (difference included angle) between the reference signal and the comparison signal with an amplitude difference threshold value (difference included angle threshold value), and detecting whether the difference included angle between the reference signal and the comparison signal is not less than the difference included angle threshold value. When the difference included angle between the reference signal and the comparison signal is not less than the difference included angle threshold, it indicates that the amplitude of the ultrasonic signal in the current period meets the amplitude requirement of the echo signal, and the reference signal and the comparison signal can be determined as target signals.
As a possible implementation manner, determining the amplitude difference threshold corresponding to the current period includes:
and determining an amplitude difference value threshold value corresponding to the current period according to the time interval between the current time and the time of transmitting the ultrasonic signal.
That is, different amplitude difference thresholds may be set in advance for different time intervals from the time at which the ultrasonic signal is transmitted, and the amplitude difference threshold decreases as time increases. For example, if the time interval between the time interval and the time of transmitting the ultrasonic signal is within t1 second, the amplitude difference threshold is set to K1, if the time interval between the time interval and the time of transmitting the ultrasonic signal is greater than t1 second and not greater than t2 second, the amplitude difference threshold is set to K2, and if the time interval between the time interval and the time of transmitting the ultrasonic signal is greater than t2 second and not greater than t3 second, the amplitude difference threshold is set to K3, where K1 is greater than K2, and K2 is greater than K3. In this way, since the amplitude difference threshold corresponding to different time intervals of the time when the ultrasonic signal is transmitted is preset, the ultrasonic sensor chip can determine the time when the ultrasonic signal is transmitted first, in some embodiments, when the ultrasonic sensor chip can transmit the ultrasonic signal from the ultrasonic transmitting sensor, the timer is triggered to time, and the ultrasonic sensor chip can directly determine the time when the ultrasonic signal is transmitted from the timer. In some embodiments, the ultrasonic sensor chip may obtain the time at which the ultrasonic signal is emitted from the ultrasonic emission sensor. Of course, the ultrasonic sensor chip may also determine the time when the ultrasonic signal is transmitted by other means, which is not limited in this application. After the ultrasonic sensor chip determines the time for transmitting the ultrasonic signal, the amplitude difference threshold corresponding to the current period can be determined according to the time interval between the current time and the time for transmitting the ultrasonic signal. Therefore, whether the reference signal and the comparison signal are the target signals or not is determined through the amplitude difference threshold, the possibility of misjudgment can be reduced, the judgment result is not influenced no matter how the phase angles of the read reference signal and the comparison signal are, and the accuracy of the target echo signal is improved.
Likewise, there may be no corresponding timer, i.e. there are several amplitude difference thresholds stored in advance, and these amplitude difference thresholds are time-related, as described above, but only the amplitude difference threshold information is stored in the storage module, and during comparison, the threshold information at different addresses in the storage module is read and input to the comparison module for comparison with the change of the clock. The method can save hardware circuits, simplify data processing flow and improve processing speed. At this time, determining the amplitude difference threshold corresponding to the current period includes: one of a plurality of amplitude difference threshold values is read based on a clock cycle.
That is, a plurality of preset amplitude difference threshold values are stored in the storage module, and the amplitude difference threshold values stored in the storage module correspond to different clock cycles, so that the amplitude difference threshold values in the storage module can be directly read along with the change of the clock cycles. The ultrasonic sensor chip can acquire a corresponding amplitude difference threshold value according to the current clock cycle so as to judge whether the reference signal and the comparison signal are target signals.
In some embodiments, when the reference signal and the comparison signal are target signals, the preset reading frequency is updated to the first frequency, and updating the number of the target signals includes:
and when the reference signal and the comparison signal are target signals, updating the preset reading frequency to a first frequency, updating the number of the target signals, and storing the reference signal and the comparison signal.
That is, when it is determined that the currently read reference signal and the comparison signal are the target signals, the ultrasonic sensor chip may update the preset reading frequency to the first frequency, update the number of the target signals, and store the read reference signal and the comparison signal, so that the ultrasonic signal corresponding to the target echo signal may be fitted through the read reference signal and the comparison signal in the following.
In some embodiments, when the reference signal and the comparison signal are target signals, the preset reading frequency is updated to the first frequency, and updating the number of the target signals includes:
and when the reference signal and the comparison signal are target signals, updating the preset reading frequency to a first frequency, updating the number of the target signals, and deleting the reference signal and the comparison signal.
That is, in order to reduce the use of the memory space, the ultrasonic sensor chip may directly discard the read reference signal and the comparison signal after determining that the reference signal and the comparison signal are the target signals, updating the preset read frequency to the first frequency and updating the number of the target signals, that is, delete the read reference signal and the comparison signal, and only record the number of the target signals without storing the read reference signal and the comparison signal, so that the use of the memory space may be greatly reduced, and the overhead on hardware may be reduced.
As a possible implementation, the first frequency is half a wave period of the ultrasonic excitation signal (or the target echo signal). The target echo signal required by the ultrasonic sensor chip is actually an ultrasonic signal obtained by reflecting the ultrasonic signal emitted by the corresponding ultrasonic emission sensor by an obstacle. Therefore, the wave period of the target echo signal is the same as the wave period of the ultrasonic wave signal emitted by its corresponding ultrasonic wave emitting sensor. That is, the wave period of the target echo signal can be known in advance, so when the reference signal and the comparison signal are the target signals, in order to improve the accuracy of the determination result, the number of reading times can be increased, that is, the reading period is reduced, the reading period is adjusted to be half of the wave period, so that the reference signal and the comparison signal can be read once in half of the wave period, and the corresponding determination of the target signal can be performed.
In some embodiments, the first frequency may be other times, for example, in order to further simplify the circuits in the ultrasonic sensor chip and reduce the read data, the first frequency may be set to one wave period of the ultrasonic signal, so that the reading of the reference signal and the comparison signal may be performed once per wave period, and whether the read reference signal and the comparison signal are the target signal or not may be determined. Of course, the first frequency may also be set to other times, such as a quarter-wave period of the ultrasonic signal, and the like, which is not limited in this application.
Since the first frequency is not less than the second frequency, the first frequency is greater than or equal to the second frequency. When the first frequency is greater than the second frequency, the ultrasonic sensor chip may update the preset reading interval to the first frequency when it is determined that the reference signal and the comparison signal read in the current cycle are the target signals, and update the preset reading interval to the second frequency when it is determined that the reference signal and the comparison signal read in the current cycle are not the target signals. In this way, when the reference signal and the comparison signal read in the current cycle are determined as the target signals, the ultrasonic sensor chip can read in the cycle of the first frequency, thereby shortening the reading cycle and increasing the number of times of reading. When the reference signal and the comparison signal read in the current period are determined not to be the target signal, reading can be performed by taking the second frequency as the period, unnecessary reading can be avoided, and the reading times are reduced, so that the use of the memory space is reduced, and the hardware overhead is reduced.
As a possible implementation, the first frequency is twice the second frequency.
As a possible implementation, the second frequency is a wave period of the ultrasonic signal.
And step S303, judging whether a target echo signal appears or not based on whether the number of the target signals is larger than a preset value or not.
In this embodiment, after the number of the target signals is updated in the above steps, the ultrasonic sensor chip may determine whether the read reference signal and the comparison signal are the target echo signals according to the number of the target signals.
In some embodiments, a threshold value for the number of read reference signals and comparison signals as target signals may be preset, such that determining whether the read reference signals and comparison signals are target echo signals based on the number of target signals comprises: and when the number of the target signals reaches a preset value, determining the read reference signals and the comparison signals as target echo signals.
That is, in order to more accurately determine whether the read ultrasonic signal is the target echo signal required by the ultrasonic sensor chip, a number threshold value may be preset for the read reference signal and the comparison signal to be the target signal, so that, after the number of the target signals is updated in the above steps, the ultrasonic sensor chip may compare the number of the recorded target signals with a preset value, and when the number of the target signals is equal to or greater than the preset value, it indicates that the number of the read reference signal and the comparison signal as the target signals reaches the preset threshold value, and at this time, it may be determined that the read reference signal and the comparison signal are the target echo signal.
Further, when the number of the target signals does not reach the preset threshold, it indicates that the number of the currently read reference signals and the number of the comparison signals are small, at this time, S301 to S303 may be executed again until the number of the target signals reaches the preset threshold, and the read reference signals and the comparison signals are determined as the target echo signals.
Therefore, in the embodiment of the application, the echo signal is judged by periodically reading the reference signal and the comparison signal, and the echo signal is not required to be judged after the reflected signal is completely received, so that the read data volume can be greatly reduced, and the hardware overhead is reduced. In addition, corresponding threshold judgment is not required to be carried out after all the transmitting signals are received or the peak values are extracted, the processing speed of echo judgment is increased, and therefore the efficiency of echo detection is improved.
For example, after the ultrasonic wave transmitting sensor transmits the ultrasonic wave signal a, the ultrasonic wave transmitting sensor is reflected by an obstacle, and the ultrasonic wave receiving sensor may receive the ultrasonic wave signal b and send the ultrasonic wave signal b to the ultrasonic wave sensor chip as an echo signal, as shown in fig. 5, where the ultrasonic wave signal b is a sine wave with a wave period T. The ultrasonic sensor chip reads the ultrasonic signal b at a preset reading frequency. Assume that the reference signal is read at time t1 and the comparison signal is read at time t 2. The preset reference value is here 0 volt. If the amplitude of the reference signal read at time t1 in the current cycle is 0 volt, the amplitude of the comparison signal is V1 volt. The ultrasonic sensor chip detects whether the amplitude of the reference signal is a preset reference value. When the amplitude of the reference signal read at the time t1 in the current period is 0 v, the ultrasonic sensor chip determines that the amplitude information of the reference signal is the preset reference value. At this time, the ultrasonic sensor chip may determine that the threshold corresponding to the current period is an amplitude threshold. At this time, the ultrasonic sensor chip may read the time of transmitting the ultrasonic signal from the timer, and determine the amplitude threshold corresponding to the current period as Vth1 according to the time interval between the current time and the time of transmitting the ultrasonic signal (the amplitude threshold may also be read according to the clock period without using the timer). The ultrasonic sensor chip compares the amplitude V1 of the comparison signal read in the current period with the amplitude threshold Vth1 corresponding to the current period. And when the amplitude V1 of the comparison signal is greater than the amplitude threshold Vth1 corresponding to the current period, determining the reference signal and the comparison signal read in the current period as target signals, adding 1 to the number of the target signals, and updating the number of the target signals. And the ultrasonic sensor chip may update the preset reading frequency to a first frequency, which is assumed to be a half wave period of the ultrasonic signal a. At this time, the ultrasonic sensor chip reads the reference signal and the comparison signal at a time interval of half a wave cycle in the next reading. That is, the reading time of the reference signal and the comparison signal at the next time and the reading time of the reference signal and the comparison signal at the current time are separated by half a wave period, that is, the reference signal and the comparison signal at the next period, that is, t3 is the reference signal at the next period, t4 is the comparison signal at the next period, and the voltage corresponding to t4 is V4, as shown in fig. 6 a.
The ultrasonic sensor chip detects whether the number of the target signals reaches a preset threshold value, and when the number of the target signals reaches the preset threshold value, the acquired reference signals and the comparison signals are determined to be target echo signals. That is, since the currently read reference signal and the comparison signal are both the ultrasonic signal b, it can be directly determined that the ultrasonic signal b is the target echo signal. And reading the reference signal and the comparison signal again according to the preset reading frequency when the number of the target signals detected by the ultrasonic sensor chip does not reach the preset threshold value. At this time, since the preset reading frequency is updated to the first frequency, the ultrasonic sensor chip needs to read at the first frequency when reading the reference signal next time. Similarly, when the next comparison signal is read, the reading is also performed at the first frequency.
Or when the amplitude V1 of the comparison signal is smaller than the amplitude threshold Vth1 corresponding to the current period, the ultrasonic sensor chip determines that the reference signal read in the current period and the comparison signal are determined not to be the target signal, and the ultrasonic sensor chip clears the number of the target signals. The ultrasonic sensor chip may update the preset reading frequency to the second frequency. The second frequency is assumed to be one wave period of the ultrasonic signal a. At this time, the ultrasonic sensor chip reads the reference signal and the comparison signal at intervals of one wave cycle in the next reading. That is, the reading time of the reference signal and the comparison signal at the next time and the reading time of the reference signal and the comparison signal at the current time are separated by one wave cycle, that is, the reference signal and the comparison signal at the next cycle, that is, t3 is the reference signal at the next cycle, t4 is the comparison signal at the next cycle, and the voltage corresponding to t4 is V4, as shown in fig. 6 b.
Alternatively, if the amplitude of the reference signal read at time t1 in the current period is V2 volts, the amplitude of the comparison signal is V1 volts. When the ultrasonic sensor chip detects whether the amplitude of the reference signal is a preset reference value, the ultrasonic sensor chip determines the amplitude of the reference signal because the amplitude of the reference signal read at the time t1 in the current period is V2V and not 0VThe information is not a preset reference value. At this time, the ultrasonic sensor chip may determine that the threshold corresponding to the current period is an amplitude difference threshold. The ultrasonic sensor chip may read a time at which the ultrasonic signal is transmitted from the timer, and determine that the amplitude difference threshold corresponding to the current period is K1 according to a time interval between the current time and the time at which the ultrasonic signal is transmitted (or read the amplitude difference threshold according to a clock period without using the timer). The ultrasonic sensor chip can calculate the amplitude difference value of the reference signal and the comparison signal according to the amplitude information V2V of the reference signal and the amplitude information V1V of the comparison signal read in the current period, and then judge whether the reference signal and the comparison signal are target signals according to the amplitude difference value of the reference signal and the comparison signal and an amplitude difference value threshold value. In this example, the amplitude difference angle may be used for comparison in order to more accurately compare the amplitude difference value with the amplitude difference threshold value. That is, the ultrasonic sensor chip may calculate the amplitude difference included angle between the reference signal and the comparison signal according to the amplitude information V2V of the reference signal read in the current cycle, the amplitude information V1V of the comparison signal, the reading time t1 of the reference signal, and the reading time t2 of the comparison signal, as shown in fig. 7 a. For example, can be represented by the formula tan θ = (V) 0 -V 0 ')/L calculates the amplitude difference angle between the reference signal and the comparison signal. Wherein tan theta represents the amplitude difference angle between the reference signal and the comparison signal, V 0 Representing amplitude information of the comparison signal, V 0 ' denotes amplitude information of the reference signal, and L denotes a time interval between the reference signal and the comparison signal. At this time, the ultrasonic sensor can calculate an amplitude difference angle tan θ = (V1-V2)/(t 2-t 1) between the reference signal and the comparison signal. After the amplitude difference included angle between the reference signal read in the current period and the comparison signal is calculated, the amplitude difference threshold value K1 corresponding to the current period, which is obtained by the ultrasonic sensor, is the amplitude difference included angle threshold value. And the ultrasonic sensor compares the amplitude difference included angle of the reference signal and the comparison signal with an amplitude difference included angle threshold value. When the included angle of the amplitude difference value of the reference signal and the comparison signal is larger than the threshold value of the included angle of the amplitude difference value, the reference signal and the comparison signal are determined as target signals, and the target signals are obtainedAnd adding 1 to the number of the target signals, and updating the number of the target signals. And the ultrasonic sensor chip may update the preset reading frequency to a first frequency, which is assumed to be a half wave period of the ultrasonic signal a. At this time, the ultrasonic sensor chip reads the reference signal and the comparison signal at a time interval of a half-wave cycle in the next reading. That is, the reading time of the next reference signal and comparison signal is separated from the reading time of the current reference signal and comparison signal by half a wave period, that is, the reference signal and comparison signal of the next period, that is, t3 is the reference signal of the next period, t4 is the comparison signal of the next period, the voltage corresponding to t3 is V3, and the voltage corresponding to t4 is V4, as shown in fig. 7 a.
The ultrasonic sensor chip detects whether the number of the target signals reaches a preset threshold value, and when the number of the target signals reaches the preset threshold value, the acquired reference signals and the comparison signals are determined to be target echo signals. That is, since the currently read reference signal and the comparison signal are both the ultrasonic signal b, it can be directly determined that the ultrasonic signal b is the target echo signal. And reading the reference signal and the comparison signal again according to the preset reading frequency when the number of the target signals detected by the ultrasonic sensor chip does not reach the preset value. At this time, since the preset reading frequency is updated to the first frequency, the ultrasonic sensor chip needs to read at the first frequency when reading the reference signal next time. Similarly, when the next comparison signal is read, the reading is also performed at the first frequency.
Or when the amplitude difference value between the reference signal and the comparison signal is smaller than the amplitude difference value threshold (or the amplitude difference included angle is smaller than the amplitude difference value included angle threshold), the ultrasonic sensor chip determines that the reference signal and the comparison signal read in the current period are determined not to be the target signals, and the ultrasonic sensor chip clears the number of the target signals. The ultrasonic sensor chip may update the preset reading frequency to the second frequency. The second frequency is assumed to be one wave period of the ultrasonic signal a. At this time, the ultrasonic sensor chip reads the reference signal and the comparison signal at intervals of one wave cycle in the next reading. That is, the reading time of the reference signal and the comparison signal at the next time and the reading time of the reference signal and the comparison signal at the current time are separated by one wave cycle, that is, the reference signal and the comparison signal at the next cycle, that is, t3 is the reference signal at the next cycle, t4 is the comparison signal at the next cycle, the voltage corresponding to t3 is V3, and the voltage corresponding to t4 is V4, as shown in fig. 7 b.
In this way, the reading and comparison of the ultrasonic signals are performed in the above manner, and when it is determined that the read reference signal and the comparison signal are not the target signal, that is, do not meet the requirement of the target echo signal, the read reference signal and the comparison signal are discarded, and the reference signal and the comparison signal are not read in this period, or the read reference signal and the comparison signal are not processed, or the read reference signal and the comparison signal are discarded. When the read reference signal and the comparison signal are determined to be target signals, namely, the read reference signal and the comparison signal meet the requirement of a target echo signal, the reference signal and the comparison signal which are read this time can be stored, the next reading of the reference signal and the comparison signal is carried out by taking the first frequency as a period, whether the read reference signal and the comparison signal are the target signals or not is detected, the read reference signal and the comparison signal can be continuously stored when the next reference signal and the comparison signal are the target signals until the number of the acquired reference signal and the acquired comparison signal which are the target signals reaches a preset value, the acquired reference signal and the acquired comparison signal can be determined to be the target echo signal, and therefore the subsequent calculation of the distance between obstacles can be continued. By means of the method for determining the target echo signal, the read data volume of the ultrasonic signal can be greatly reduced, hardware cost is reduced, collected reference signals and comparison signals which do not meet requirements are abandoned, and extra memory or buffer space is not occupied. In addition, in the embodiment of the application, whether the received ultrasonic waves are the target echo signals or not does not need to be judged after the ultrasonic receiving sensor finishes transmitting all the received ultrasonic waves or extracts the peak values, the judgment speed of the target echo signals is increased, and the echo detection efficiency is improved. Furthermore, in the embodiment of the application, the reading point does not need to be set at the comparison threshold or the peak, the reading time and the reading period can be set more flexibly, and the flexibility of echo detection is improved.
In fig. 6a-7b, the reading signal is taken at a second frequency for non-compliant signals that occur before the occurrence of a compliant target signal.
It should be noted that, when the first frequency is used to read data, for example, the first frequency is 2 times the frequency of the excitation signal, two satisfactory target signals will appear within one waveform period, and therefore, when it is finally determined whether a target echo signal appears based on whether the number of the target signals is greater than a preset value, the corresponding number should also be 2 times the waveform, for example, when 5 satisfactory target signals appear, 10 satisfactory comparison results will appear.
Fig. 8 is a schematic structural diagram of an ultrasonic sensor chip according to an embodiment of the present disclosure. As shown in fig. 8, the ultrasonic sensor chip includes: a sampling circuit 801, a filter circuit 802, and a read processing circuit 803.
A sampling circuit 801 is coupled to the ultrasound transducer to sample the echo signals.
And the filtering circuit 802 is electrically connected to the sampling circuit 801 and is configured to filter the echo signal input by the sampling circuit 801 to output an echo signal with a preset frequency.
The reading processing circuit 803 is electrically connected to the filter circuit 802, and is configured to determine whether the input echo signal with the preset frequency is a target echo signal.
As shown in fig. 9a, the reading processing circuit 803 includes a reading module 8031, a comparing module 8032, a controlling module 8033, and a determining module 8034.
The reading module 8031 is electrically connected to the filter circuit 802, and is configured to periodically read a first point signal and a second point signal of an echo signal with a preset frequency according to a preset reading frequency.
The first point signal is used as a reference signal, the second point signal is used as a comparison signal, and the reading time interval between the reference signal and the comparison signal is preset.
The comparing module 8032 is electrically connected to the reading module 8031, and is configured to receive amplitude information of the reference signal and the comparison signal input by the reading module 8031, and determine whether the reference signal and the comparison signal are the target signal.
A control module 8033, electrically connected to the comparing module 8032 and the reading module 8031, configured to receive a comparison result of the comparing module 8031, and update a preset reading frequency of the reading module 8031 to a first frequency and update the number of target signals when the reference signal and the comparison signal are target signals; when the reference signal and the comparison signal are not the target signals, the preset reading frequency of the reading module 8031 is updated to a second frequency, and the number of the target signals is restored to or maintained at an initial value, such as zero clearing.
Wherein the first frequency is not less than the second frequency.
The determining module 8034 is electrically connected to the control module 8033, and is configured to read quantity data of the target signals of the control module 8033, and determine that a target echo signal occurs if the quantity of the target signals is greater than a preset value.
As a possible implementation manner, the ultrasonic sensor chip further includes, as shown in fig. 9 b: and a module 804 is stored.
The storage module 804 is configured to store a plurality of threshold data.
The comparison module 8032 is also electrically coupled to the memory module 804. The comparing module 8032 is specifically configured to read threshold data for determining whether the reference signal and the comparison signal are the target signal.
As one possible implementation, comparing module 8032: if the amplitude information of the reference signal is a preset reference value, reading threshold data corresponding to the current period in the storage module 804, wherein the threshold data is an amplitude threshold; comparing whether the amplitude information of the comparison signal is not less than an amplitude threshold corresponding to the current period; and if the amplitude information of the comparison signal is not less than the amplitude threshold corresponding to the current period, determining the reference signal and the comparison signal as target signals, and outputting the comparison result outwards.
As a possible implementation manner, the comparing module 8032 is specifically configured to: and determining the moment of transmitting the ultrasonic signal, and determining the amplitude threshold corresponding to the current period according to the time interval between the current moment and the moment of transmitting the ultrasonic signal.
Alternatively, one of the plurality of amplitude thresholds is read based on the clock cycle.
Alternatively, as a possible implementation manner, the comparing module 8032 is specifically configured to: if the amplitude information of the reference signal is not the preset reference value, reading threshold data corresponding to the current period in the storage module 804, wherein the threshold data is an amplitude difference threshold, and determining an amplitude difference between the reference signal and the comparison signal based on the amplitude information of the reference signal and the amplitude information of the comparison signal; comparing whether the amplitude difference value is not less than an amplitude difference value threshold value; and when the amplitude difference value is not less than the amplitude difference value threshold value, determining the reference signal and the comparison signal as target signals, and outputting a comparison result outwards.
As a possible implementation manner, the comparing module 8032 is specifically configured to: and determining the moment of transmitting the ultrasonic driving signal, and determining the amplitude difference threshold value corresponding to the current period according to the time interval between the current moment and the moment of transmitting the ultrasonic driving signal. Alternatively, one of a plurality of amplitude difference thresholds is read based on a clock cycle.
As a possible implementation, the first frequency is twice the second frequency.
As a possible implementation manner, the control module 8033 is specifically configured to, when the reference signal and the comparison signal are target signals, update the preset reading frequency of the reading module 8031 to the first frequency, update the number of the target signals, and delete the reference signal and the comparison signal.
Corresponding to the embodiment, the application also provides an automobile ultrasonic radar device. Fig. 10 is a schematic structural diagram of an automotive ultrasonic radar device according to an embodiment of the present invention, where the automotive ultrasonic radar device includes an ultrasonic transducer 1001 and an ultrasonic sensor chip 1002. The ultrasonic sensor chip 1002 is the ultrasonic sensor chip described in the above embodiments.
The ultrasonic sensor chip 1002 is electrically connected to the ultrasonic transducer 1001, and is configured to determine whether an echo signal received by the ultrasonic transducer 1001 is a target echo signal.
As a possible implementation manner, the ultrasonic radar apparatus for an automobile further includes, as shown in fig. 11: and a microprocessor chip 1003.
The micro-processing chip 1003 is electrically connected to the ultrasonic sensor chip 1002, and is configured to send a trigger signal to the ultrasonic sensor chip 1002 and receive an indication signal of a target echo signal sent by the ultrasonic sensor chip 1002.
The ultrasonic sensor chip 1002 is further configured to receive the trigger signal sent by the microprocessor chip 1003, generate a driving signal for driving the ultrasonic transducer 1001 to emit an ultrasonic wave according to the trigger signal, and send an indication signal of a target echo signal to the microprocessor chip 1003 when it is determined that the echo signal received by the ultrasonic transducer 1001 is the target echo signal.
The microprocessor chip is generally called an ECU or a domain controller in an automobile, and may be a micro central control chip or a system-on-chip capable of processing digital signals or analog signals, or performing functions such as signal control, instruction processing, and arithmetic operations, such as an MCU, a DSP, an MPU, or a micro CPU.
Those skilled in the art will readily appreciate that the techniques of the embodiments of the present invention may be implemented using software plus any required general purpose hardware platform. Based on such understanding, the technical solutions in the embodiments of the present invention may be substantially or partially embodied in the form of a software product, which may be stored in a storage medium, such as a ROM/RAM, a magnetic disk, an optical disk, or the like, and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network device) to execute the method according to the embodiments or some parts of the embodiments.
The same and similar parts in the various embodiments in this specification may be referred to each other. Especially, as for the device embodiment and the terminal embodiment, since they are basically similar to the method embodiment, the description is relatively simple, and the relevant points can be referred to the description in the method embodiment.

Claims (16)

1. An echo signal detection method of an ultrasonic sensor, comprising:
periodically reading a first point signal and a second point signal of an echo signal according to a preset reading frequency, wherein the first point signal is used as a reference signal, the second point signal is used as a comparison signal, and the reading time interval between the reference signal and the comparison signal is preset;
determining whether the reference signal and the comparison signal are target signals based on amplitude information of the reference signal and the comparison signal; when the reference signal and the comparison signal are target signals, updating the preset reading frequency to a first frequency, and updating the number of the target signals; when the reference signal and the comparison signal are not target signals, updating the preset reading frequency to a second frequency, and recovering or maintaining the number of the target signals to or at an initial value; the first frequency is not less than the second frequency;
and judging whether a target echo signal appears or not based on whether the number of the target signals is larger than a preset value or not.
2. The method of claim 1, wherein the first frequency is twice the second frequency.
3. The method of claim 1, wherein determining whether the reference signal and the comparison signal are target signals based on amplitude information of the reference signal and the comparison signal comprises:
detecting whether the amplitude information of the reference signal is a preset reference value or not;
if the amplitude information of the reference signal is a preset reference value, determining an amplitude threshold corresponding to the current period;
detecting whether the amplitude information of the comparison signal is not less than an amplitude threshold corresponding to the current period;
and if the amplitude information of the comparison signal is not less than the amplitude threshold corresponding to the current period, determining that the reference signal and the comparison signal are target signals.
4. The method of claim 3,
the determining the amplitude threshold corresponding to the current period includes:
and determining the moment of transmitting the ultrasonic driving signal, and determining the amplitude threshold corresponding to the current period according to the time interval between the current moment and the moment of transmitting the ultrasonic driving signal.
5. The method of claim 3,
the determining the amplitude threshold corresponding to the current period includes:
one of a plurality of amplitude thresholds is read according to a clock cycle.
6. The method of claim 3, further comprising:
if the amplitude information of the reference signal is not a preset reference value, determining an amplitude difference value threshold value corresponding to the current period, and determining the amplitude difference value between the reference signal and the comparison signal based on the amplitude information of the reference signal and the amplitude information of the comparison signal;
detecting whether the amplitude difference value is not less than the amplitude difference value threshold value;
and when the amplitude difference value is not smaller than the amplitude difference value threshold value, determining the reference signal and the comparison signal as target signals.
7. The method of claim 6,
the determining the amplitude difference threshold corresponding to the current period includes:
and determining the moment of transmitting the ultrasonic driving signal, and determining an amplitude difference value threshold value corresponding to the current period according to the time interval between the current moment and the moment of transmitting the ultrasonic driving signal.
8. The method of claim 6,
the determining the amplitude difference threshold corresponding to the current period includes:
one of a plurality of amplitude difference threshold values is read based on a clock cycle.
9. The method according to any one of claims 1-8, wherein when the reference signal and the comparison signal are target signals, then updating the preset reading frequency to a first frequency, and updating the number of target signals comprises:
and when the reference signal and the comparison signal are target signals, updating the preset reading frequency to a first frequency, updating the number of the target signals, and deleting the reference signal and the comparison signal.
10. An ultrasonic sensor chip is characterized by comprising a sampling circuit, a filter circuit and a reading processing circuit;
the sampling circuit is coupled to the ultrasonic transducer to sample the echo signals;
the filtering circuit is electrically connected with the sampling circuit and is used for filtering the echo signal input by the sampling circuit to output an echo signal with a preset frequency;
the reading processing circuit is electrically connected with the filter circuit and is used for judging whether the input echo signal with the preset frequency is a target echo signal or not;
the reading processing circuit comprises a reading module, a comparison module, a control module and a judgment module;
the reading module is electrically connected with the filter circuit and is used for periodically reading a first point signal and a second point signal of the echo signal with the preset frequency according to a preset reading frequency, the first point signal is used as a reference signal, the second point signal is used as a comparison signal, and the reading time interval between the reference signal and the comparison signal is preset time;
the comparison module is electrically connected with the reading module and is used for receiving the amplitude information of the reference signal and the comparison signal input by the reading module and determining whether the reference signal and the comparison signal are target signals;
the control module is electrically connected with the comparison module and the reading module and is used for receiving a comparison result of the comparison module, updating the preset reading frequency of the reading module to a first frequency and updating the number of the target signals when the reference signal and the comparison signal are target signals; when the reference signal and the comparison signal are not target signals, updating the preset reading frequency of the reading module to a second frequency, and recovering or maintaining the number of the target signals to an initial value; the first frequency is not less than the second frequency;
the judging module is electrically connected with the control module and used for reading the quantity data of the target signals of the control module and judging that target echo signals appear if the quantity of the target signals is larger than a preset value.
11. The chip of claim 10, further comprising a memory module,
the storage module is used for storing a plurality of threshold data;
the comparison module is also electrically connected with the storage module to read the threshold data for judging whether the reference signal and the comparison signal are target signals.
12. The chip of claim 11,
the comparison module is specifically configured to: if the amplitude information of the reference signal is a preset reference value, reading threshold data corresponding to the current period in the storage module, wherein the threshold data is an amplitude threshold; comparing whether the amplitude information of the comparison signal is not less than the amplitude threshold corresponding to the current period; and if the amplitude information of the comparison signal is not less than the amplitude threshold corresponding to the current period, determining that the reference signal and the comparison signal are target signals, and outputting a comparison result outwards.
13. The chip of claim 11,
the comparison module is specifically configured to: if the amplitude information of the reference signal is not a preset reference value, reading threshold data corresponding to the current period in the storage module, wherein the threshold data is an amplitude difference threshold, and determining the amplitude difference between the reference signal and a comparison signal based on the amplitude information of the reference signal and the amplitude information of the comparison signal; comparing whether the amplitude difference value is not less than the amplitude difference value threshold value; and when the amplitude difference value is not less than the amplitude difference value threshold value, determining the reference signal and the comparison signal as target signals, and outputting a comparison result outwards.
14. The chip according to any of claims 10-13, wherein the first frequency is twice the second frequency.
15. An automotive ultrasonic radar device, characterized by comprising an ultrasonic transducer and the ultrasonic sensor chip of any one of claims 10 to 14;
the ultrasonic sensor chip is electrically connected with the ultrasonic transducer and used for judging whether the echo signal received by the ultrasonic transducer is a target echo signal.
16. The ultrasonic radar apparatus of claim 15, further comprising: a microprocessor chip;
the micro-processing chip is electrically connected with the ultrasonic sensor chip and is used for sending a trigger signal to the ultrasonic sensor chip and receiving an indication signal of a target echo signal sent by the ultrasonic sensor chip;
the ultrasonic sensor chip is further configured to receive a trigger signal sent by the microprocessor chip, generate a driving signal for driving the ultrasonic transducer to emit ultrasonic waves according to the trigger signal, and send an indication signal of the target echo signal to the microprocessor chip when it is determined that the echo signal received by the ultrasonic transducer is the target echo signal.
CN202211667300.6A 2022-12-23 2022-12-23 Echo signal detection method, chip and device of ultrasonic sensor Pending CN115932810A (en)

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Application Number Priority Date Filing Date Title
CN202211667300.6A CN115932810A (en) 2022-12-23 2022-12-23 Echo signal detection method, chip and device of ultrasonic sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211667300.6A CN115932810A (en) 2022-12-23 2022-12-23 Echo signal detection method, chip and device of ultrasonic sensor

Publications (1)

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