An ultrasonic wave transmitting-receiving circuit time delay measuring and ultrasonic wave time of flight correcting method

Abstract

The application relates to an ultrasonic wave transmitting and receiving circuit time delay measurement and ultrasonic wave flight time correction method, and belongs to the technical field of coal mine gas extraction monitoring. An ultrasonic wave flow measurement circuit is built, the ultrasonic wave flow measurement circuit comprises a microprocessor, a transmitting circuit, an ultrasonic wave probe one, a circuit switching switch one, a circuit switching switch two, an ultrasonic wave probe two and a receiving circuit; the circuit is switched through the control circuit switching switch, the access and disconnection of the ultrasonic wave probe are controlled, when the ultrasonic wave probe is not accessed, the whole circuit is a closed loop circuit which is sequentially connected in series, the propagation and detection of the analog ultrasonic wave are simulated, then the ultrasonic wave probe is accessed into the circuit, a closed loop transmission loop of signal transmission in the above sequence is formed, the detection of the ultrasonic wave is carried out, the propagation time of the two is compared and subtracted, so that the accurate flight time is obtained by eliminating the hardware delay. The scheme is more thorough in flight time correction, there is no hardware RC delay, and the defect that the RC delay is affected by the pipe diameter of a pipeline is overcome.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of coal mine gas extraction monitoring, and particularly relates to an ultrasonic wave transmitting-receiving circuit time delay measurement and ultrasonic wave flight time correction method. BACKGROUND

[0002] The ultrasonic wave measuring device utilizes the time difference phenomenon of ultrasonic wave propagation in forward and reverse flow media to measure the flow rate (volume) of the media, has the advantages of low measurement lower limit, wide measurement range, high measurement accuracy, no rotating measurement components, and dirt resistance, and is currently applied more in the fields of meteorological wind speed measurement, pipeline liquid flow measurement, and natural gas flow measurement. However, in the field of coal mine gas extraction measurement, the working conditions of coal mine gas extraction are complex and changeable, the pipeline specifications are different, the medium pressure is small, and the composition is complex. The key point of the ultrasonic wave gas flow measurement equipment based on the ultrasonic wave transit time difference measurement principle is to accurately obtain the transit time of the ultrasonic wave between the transmitting probe and the receiving probe. The existing method for obtaining the ultrasonic wave transit time is mainly through the hardware measurement circuit combined with the software algorithm, and the time obtained not only has the pure transit time of the ultrasonic wave, but also superimposes the time delay caused by the RC in the hardware circuit.

[0003] For example, the Chinese patent with the publication number CN103812477B proposes an ultrasonic wave transmitting circuit time delay measurement method and ultrasonic wave transmitting correction method, which controls the delay time of the pre-measurement sequence ultrasonic wave transmitting driving pulse, dynamically adjusts the subsequent ultrasonic wave driving pulse, and improves the beam focusing effect. This method corrects the error of RC delay, but only makes the error of RC delay smaller, and does not eliminate the RC delay.

[0004] The gas extraction gas conveying pipeline is composed of drilling extraction pipes, drilling field convergence pipes, extraction branch pipes, extraction main pipes, and extraction total pipes, and the corresponding pipeline inner diameters gradually increase, and the inner diameters are mostly in the range of 50mm to 1000mm. When the ultrasonic wave measuring device is used for gas extraction measurement, the pipeline inner diameter directly affects the propagation distance of the ultrasonic wave, the smaller the pipeline diameter, the shorter the propagation time, the shorter the propagation time, the greater the time delay caused by the hardware, and the greater the influence on the flow measurement accuracy. Due to the geographical location and safety factors, the inner diameter of the gas extraction pipeline is usually an uncontrollable factor, and therefore, the existing technology usually considers that the ultrasonic wave measuring device has poor adaptability for gas extraction measurement and monitoring. SUMMARY

[0005] Therefore, the present application aims to provide an ultrasonic transmitting-receiving circuit time delay measurement and ultrasonic time of flight correction method, solve the problem that the RC circuit time delay in the ultrasonic flow measurement device affects the flow measurement result, correct the measured ultrasonic transit time parameter of the flow measurement device, effectively improve the measurement accuracy of the ultrasonic time of flight, improve the flow measurement accuracy, and improve the adaptability of the flow measurement device in the gas extraction metering and monitoring field.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions.

[0007] An ultrasonic transmitting-receiving circuit time delay measurement and ultrasonic time of flight correction method, an ultrasonic flow measurement circuit is built, the ultrasonic flow measurement circuit includes a microprocessor, an ultrasonic probe one, an ultrasonic probe two, a circuit switching switch one and a circuit switching switch two; the circuit switching switch one and the circuit switching switch two both have at least two output ends; the microprocessor is electrically connected with a transmitting circuit; the transmitting circuit is connected with the input end of the circuit switching switch one, one output end of the circuit switching switch one is connected with the ultrasonic probe one, the other output end of the circuit switching switch one is connected with one output end of the circuit switching switch two, the other output end of the circuit switching switch two is connected with the ultrasonic probe two, the input end of the circuit switching switch two is connected with a receiving circuit, and the receiving circuit is electrically connected with the microprocessor; the receiving circuit includes a TDC time detection circuit.

[0008] Based on the ultrasonic flow measurement circuit, the ultrasonic time of flight correction is performed according to the following steps.

[0009] First step: connect the circuit switching switch one and the circuit switching switch two; the microprocessor transmits a single pulse square wave signal with the same frequency as the rated frequency of the ultrasonic wave, and starts the TDC time measurement circuit to start timing at the same time; when the single pulse signal triggers the time measurement circuit to stop timing, the time counted by the TDC time measurement circuit is the delay time caused by the ultrasonic transmitting-receiving circuit, and is recorded as t y ;

[0010] Second step: switch the circuit switching switch one to the end connected with the ultrasonic probe one, and switch the circuit switching switch two to the end connected with the ultrasonic probe two; the microprocessor drives the pulse sequence signal, and starts the time measurement circuit to start timing at the same time; after the pulse sequence signal reaches the ultrasonic transmitting probe, the probe is driven to emit ultrasonic waves; after the ultrasonic waves reach the ultrasonic receiving probe, the ultrasonic receiving signal is outputted through the probe conversion; when the ultrasonic receiving signal triggers the time measurement circuit to stop timing, the time counted by the time measurement circuit is recorded as t sf ;

[0011] Third step: calculate the accurate time of flight t s ;

[0012] Step 4: Switch the ultrasonic wave's flight direction. Switch ultrasonic probe one to receiving mode and ultrasonic probe two to transmitting mode. Repeat steps 2 and 3 to measure the accurate flight time t of the ultrasonic wave in the opposite direction. n , t n =t nf -t y , where t nf This refers to the time that carries the circuit delay.

[0013] Furthermore, the transmitting circuit includes a push-pull conversion circuit and a signal power amplifier circuit that are electrically connected to each other; in the transmitting circuit, the signal transmission direction is: emitted from the microprocessor, and sequentially passes through the push-pull conversion circuit, the signal power amplifier circuit, and the circuit switching switch.

[0014] Furthermore, the receiving circuit also includes a programmable signal amplification circuit and a signal filtering circuit that are electrically connected to each other; in the receiving circuit, the signal transmission direction is: from the circuit switching switch two, through the programmable signal amplification circuit and the signal filtering circuit in sequence.

[0015] Furthermore, in the second step, the pulse sequence signal is a square wave pulse, and the number of square wave pulses is greater than 2.

[0016] Furthermore, in the third step, the method for calculating the accurate flight time is as follows: t s =t sf -t y .

[0017] Furthermore, it also includes a fifth step: detecting the ambient temperature at the location of the circuit board using a temperature sensor, and the microprocessor recording each detection time. y The ambient temperature at that time is used as the initial temperature, and the change in ambient temperature is calculated based on the initial ambient temperature and the real-time ambient temperature. When the change in ambient temperature exceeds a preset value ΔT, the microprocessor repeats the first four steps again.

[0018] Furthermore, both the circuit switching switch one and the circuit switching switch two are single-pole double-throw switches.

[0019] Definitions:

[0020] Single-pole double-throw switch: A single-pole double-throw switch consists of a moving end and a stationary end. The moving end is the so-called "pole," which should be connected to the power supply line, that is, the end where the power comes in (i.e., the input end), which is usually also the end connected to the switch handle; the other two ends are the two ends of the power supply output (i.e., the output ends), which are the so-called stationary ends.

[0021] TDC: (short for Time-to-Digital Converter)

[0022] The beneficial effects of this invention are as follows:

[0023] This solution addresses the issue that the time delay of the RC circuit in an ultrasonic flow measurement device can affect the flow measurement results. It corrects the measured ultrasonic transit time parameter of the flow measurement device, effectively improving the accuracy of ultrasonic flight time measurement, enhancing flow measurement precision, and increasing the adaptability of the flow measurement device in the field of gas extraction metering and monitoring.

[0024] In the field of gas extraction and metering monitoring, the inner diameter of the pipe directly affects the propagation distance of ultrasonic waves. The smaller the pipe diameter, the shorter the propagation time. The shorter the propagation time, the greater the impact of hardware-induced time delay, and the greater the impact on the accuracy of flow measurement. This solution first obtains the delay time caused by the ultrasonic transceiver circuit by simulating ultrasonic transmission, and then directly eliminates it. Compared with existing correction methods, the correction is more thorough, eliminates hardware RC delay, and overcomes the defect of RC delay being affected by the pipe diameter. This method does not affect the normal measurement of the ultrasonic flow measuring device, does not increase additional costs, and effectively improves the measurement stability and accuracy of the equipment. At the same time, compared with existing measurement technologies, this invention has the advantages of online autonomous measurement of time delay and real-time correction of measurement results. It can adjust the correction parameters according to the temperature of the circuit board, making it more practical.

[0025] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0027] Figure 1 A schematic diagram of the circuit connection state when the circuit delay measurement function is enabled;

[0028] Figure 2 This is a schematic diagram of the circuit connection state when the circuit delay measurement function is turned off and the circuit enters the normal measurement working state. Detailed Implementation

[0029] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0031] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0032] Please see Figures 1-2 This invention relates to a method for measuring the time delay of an ultrasonic transceiver circuit and correcting the ultrasonic time of flight. An ultrasonic current measurement circuit is constructed, comprising a microprocessor, an ultrasonic probe one, an ultrasonic probe two, a circuit switching switch one, and a circuit switching switch two. In this embodiment, both circuit switching switches one and two are single-pole double-throw switches, numbered accordingly. The microprocessor has a pulse signal output port, which is electrically connected in sequence to a push-pull converter circuit and a signal power amplifier circuit. The signal power amplifier circuit is connected to the input terminal of single-pole double-throw switch one. One output terminal of single-pole double-throw switch one is connected to ultrasonic probe one, and the other is connected to one output terminal of single-pole double-throw switch two. The other output terminal of single-pole double-throw switch two is connected to ultrasonic probe two. The input terminal of single-pole double-throw switch two is connected to a programmable signal amplifier circuit, which is electrically connected to the microprocessor after passing through a signal filtering processing circuit and a time measurement circuit (TDC).

[0033] Based on the aforementioned ultrasonic flow measurement circuit, the following steps are included:

[0034] Step 1: Connect single-pole double-throw switch one and single-pole double-throw switch two; the microprocessor transmits a single-pulse square wave signal with the same frequency as the rated frequency of the ultrasonic wave, and simultaneously starts the TDC time measurement circuit to begin timing. When the single-pulse signal triggers the time measurement circuit to stop timing, the time recorded by the TDC time measurement circuit at this time is the delay time caused by the ultrasonic transceiver circuit, denoted as t. y ;

[0035] Step 2: Switch the single-pole double-throw switch one to the end connected to the ultrasonic transmitter probe one, and switch the single-pole double-throw switch two to the end connected to the ultrasonic transmitter probe two; enable the microprocessor to drive a pulse sequence signal, which is a square wave pulse, and the number of square wave pulses is greater than 2. Simultaneously, start the time measurement circuit to begin timing; after the pulse sequence signal reaches the ultrasonic transmitter probe, it drives the probe to emit ultrasonic waves; after the ultrasonic waves reach the ultrasonic receiver probe, they are converted by the probe and output as an ultrasonic receiving signal. When the ultrasonic receiving signal triggers the time measurement circuit to end timing, the time counted by the time measurement circuit is recorded as t. sf .

[0036] Step 3: Calculate the accurate flight time t of the ultrasonic wave between the ultrasonic probe and the second ultrasonic probe. s The accurate flight time is calculated as follows: t s =t sf -t y .

[0037] Step 4: Switch the ultrasonic wave's flight direction. Switch ultrasonic probe one to receiving mode and ultrasonic probe two to transmitting mode. Repeat steps 2 and 3 to measure the accurate flight time t of the ultrasonic wave in the opposite direction. n , t n =t nf -t y , where t nf This refers to the time that carries the circuit delay.

[0038] Step 5: The ambient temperature at the location of the circuit board is detected by a temperature sensor, and the microprocessor records each detection time. y The ambient temperature at that time is used as the initial temperature, and the change in ambient temperature is calculated based on the initial ambient temperature and the real-time ambient temperature. When the change in ambient temperature exceeds a preset value ΔT (ΔT > 0.5℃), the microprocessor repeats the first four steps again.

[0039] The principle behind this solution:

[0040] This solution uses a circuit switch to control the connection and disconnection of a pair of ultrasonic probes. For example...Figure 1 As shown, when the ultrasonic probe is not connected, the entire circuit is a closed-loop circuit connected in series in sequence. The CPU (i.e., the microprocessor) drives the signal generation through the PWM interface. The signal passes through the push-pull conversion circuit, the signal power method circuit, the first single-pole double-throw switch (circuit switch S1 in the figure), the second single-pole double-throw switch (circuit switch S2 in the figure), the programmable signal amplification circuit, and the signal filtering circuit to reach the TDC time measurement circuit. After time measurement, the result is returned to the CPU to simulate the propagation and detection of ultrasonic waves. Then, a pair of ultrasonic probes are connected to the circuit, serving as the transmitter and receiver respectively, forming a closed-loop transmission circuit in which the signal is transmitted in the above sequence for ultrasonic wave detection. Since the same circuit structure is used as the simulated transmission, the accurate flight time of the ultrasonic wave transmitted from the transmitting probe to the receiving probe can be obtained simply by comparing the difference between the two propagation times.

[0041] Because hardware delays are influenced by other factors, it's impossible to directly calculate accurate hardware delays. Therefore, existing technologies correct for hardware delays to reduce errors. This solution, however, compares the transmission and reception times of a pair of ultrasonic probes transmitting and receiving signals, as well as when the same circuit is directly connected without the probes. Under the same conditions, both are affected by the same factors, and the difference directly cancels out these effects, eliminating the hardware delay and obtaining accurate flight time. This method is more thorough than existing technologies in correcting flight time, eliminates hardware RC delay, and overcomes the limitation of RC delay being affected by pipe diameter. This allows ultrasonic transceiver technology to be applied in gas extraction metering, overcoming the limitations of existing technologies in this field.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for measuring the time delay of an ultrasonic transceiver circuit and correcting the ultrasonic time of flight, characterized in that, An ultrasonic current measurement circuit is constructed, comprising a microprocessor, an ultrasonic probe one, an ultrasonic probe two, a circuit switch one, and a circuit switch two. Both circuit switches one and two have at least two output terminals. The microprocessor is electrically connected to a transmitting circuit. The transmitting circuit is connected to the input terminal of circuit switch one. One output terminal of circuit switch one is connected to ultrasonic probe one, and the other output terminal of circuit switch one is connected to one output terminal of circuit switch two. The other output terminal of circuit switch two is connected to ultrasonic probe two. The input terminal of circuit switch two is connected to a receiving circuit, which is electrically connected to the microprocessor. The receiving circuit includes a time-of-flight (TDC) detection circuit. Based on the ultrasonic current measurement circuit, ultrasonic time-of-flight correction is performed according to the following steps: Step 1: Connect circuit switch one and circuit switch two; the microprocessor emits a single-pulse square wave signal with the same frequency as the rated frequency of the ultrasonic wave, and simultaneously starts the TDC time measurement circuit to begin timing. When the single-pulse signal triggers the time measurement circuit to stop timing, the time recorded by the TDC time measurement circuit at this time is the delay time caused by the ultrasonic transceiver circuit, denoted as t. y ; Step 2: Switch circuit switch one to the end connected to ultrasonic transmitter probe one, and switch circuit switch two to the end connected to ultrasonic transmitter probe two; enable the microprocessor to drive the pulse sequence signal, and simultaneously start the time measurement circuit to begin timing; after the pulse sequence signal reaches the ultrasonic transmitter probe, it drives the probe to emit ultrasonic waves; after the ultrasonic waves reach the ultrasonic receiver probe, they are converted by the probe and output as ultrasonic receiver signals. When the ultrasonic receiver signal triggers the time measurement circuit to end timing, the time counted by the time measurement circuit is recorded as t. sf ; Step 3: Calculate the accurate flight time t of the ultrasonic wave between the ultrasonic probe and the second ultrasonic probe. s , t s =t sf -t y , where t sf This includes the time that carries the circuit delay; Step 4: Switch the ultrasonic wave's flight direction. Switch ultrasonic probe one to receiving mode and ultrasonic probe two to transmitting mode. Repeat steps 2 and 3 to measure the accurate flight time t of the ultrasonic wave in the opposite direction. n , t n =t nf -t y , where t nf This refers to the time that carries the circuit delay.

2. The method for measuring ultrasonic transceiver circuit delay and correcting ultrasonic flight time according to claim 1, characterized in that, The transmitting circuit includes a push-pull conversion circuit and a signal power amplifier circuit that are electrically connected to each other; in the transmitting circuit, the signal is transmitted in the following direction: it is emitted from the microprocessor and passes through the push-pull conversion circuit, the signal power amplifier circuit and the circuit switching switch in sequence.

3. The method for measuring ultrasonic transceiver circuit delay and correcting ultrasonic flight time according to claim 1, characterized in that, The receiving circuit also includes a programmable signal amplification circuit and a signal filtering circuit that are electrically connected to each other; in the receiving circuit, the signal transmission direction is: from the circuit switching switch two through the programmable signal amplification circuit and the signal filtering circuit in sequence.

4. The method for measuring ultrasonic transceiver circuit delay and correcting ultrasonic flight time according to claim 1, characterized in that, In the second step, the pulse sequence signal is a square wave pulse, and the number of square wave pulses is greater than 2.

5. The method for measuring ultrasonic transceiver circuit delay and correcting ultrasonic flight time according to claim 1, characterized in that, The fifth step also includes: detecting the ambient temperature at the location of the circuit board using a temperature sensor, and the microprocessor recording each detection time. y The ambient temperature at the time of the event is taken as the initial ambient temperature, and the change in ambient temperature is calculated based on the initial ambient temperature and the real-time ambient temperature. When the change in ambient temperature exceeds a preset value... Then, the microprocessor repeats the first four steps again.

6. The method for measuring ultrasonic transceiver circuit delay and correcting ultrasonic flight time according to claim 1, characterized in that, Both the circuit switching switch one and the circuit switching switch two are single-pole double-throw switches.

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