Ultrasonic wind speed and wind direction measuring device

Abstract

The invention discloses an ultrasonic wind speed and wind direction measuring device which comprises a top end structure, east, west, south and north transducer reflecting cup combinations mounted on the lower surface of the top end structure, a bottom end reflecting surface, a temperature and humidity sensor, a heating block and a signal control processing circuit device, wherein the temperature and humidity sensor and the heating block are mounted on the bottom end reflecting surface. According to the energy converter reflection cup combination, the designed reflection cups are used for reducing the lobe directional angle of a signal transmitted by the energy converter, so that the energy is more concentrated, the strength of the signal received by the energy converter at the receiving end is higher, meanwhile, the energy converter reflection cups are installed on the top end plane of the structure, and the cup openings face the bottom end plane; the bottom end plane is used as the reflecting surface, and the rain shielding characteristic of the reflecting cup is utilized, so that the surface of the transducer cannot accumulate water and freeze all the time, and the accuracy of measurement in windy and rainy weather is improved.

Description

Technical Field

[0001] The invention belongs to the field of wind speed and wind direction measurement, in particular to an ultrasonic wind speed and wind direction measuring device. Background Art

[0002] With the development of science and technology, various wind speed and direction measurement technologies have been rapidly developed. Among them, ultrasonic anemometers are widely used in ports, wind power, meteorology and other fields due to their long service life, high cost performance and strong environmental adaptability. Ultrasonic anemometers mainly transmit and receive ultrasonic waves through two pairs of transducers in the east-west and north-south directions, and calculate and process the received ultrasonic signal data through algorithms to obtain the wind speed and direction of the ambient wind. The ultrasonic lobes emitted by the transmitting transducer have main lobes and side lobes, and both the main and side lobes have large directional angles, which makes the ultrasonic energy not concentrated, resulting in weak signal strength received by the receiving transducer, which is not easy to process by algorithms. Especially in strong wind conditions, the signal is almost submerged in the noise.

[0003] Current ultrasonic anemometers, whether reflective or reflected, do not perform secondary adjustments to the ultrasonic wave lobes emitted by the transducer, causing the energy emitted to be more divergent and with a larger directional angle, resulting in a weak signal strength received by the transducer at the receiving end, which is difficult to process with an algorithm. Especially in strong wind conditions, the signal is almost drowned in the noise, making it impossible to effectively calculate the wind speed and direction.

[0004] The structure of the reflective ultrasonic anemometer currently on the market is to place the transducer on the bottom plane and reflect it on the top plane. This structure can easily cause water to accumulate on the surface of the transducer in windy and rainy weather, and cause ice to form in low temperature conditions, affecting the measurement accuracy. Summary of the invention

[0005] The purpose of the present invention is to provide an ultrasonic wind speed and direction measuring device in view of the problems existing in the above-mentioned prior art. The present invention proposes a transducer reflector cup combination, which uses the designed reflector cup to reduce the lobe pointing angle of the transducer transmission signal, so that its energy is more concentrated, thereby making the signal strength received by the receiving end transducer stronger. At the same time, the transducer reflector cup is installed on the top plane of the structure, with the cup mouth facing the bottom plane, and the bottom plane is used as a reflecting surface. The rain-shielding characteristics of the reflector cup itself are used to prevent water accumulation and ice from forming on the transducer surface, thereby improving the accuracy of measurement in windy and rainy weather.

[0006] The technical solution to achieve the purpose of the present invention is: an ultrasonic wind speed and direction measuring device, the device comprising a top structure, four sets of transducer reflector cups for east, west, south and north installed on the lower surface of the top structure, a bottom reflective surface, a temperature and humidity sensor and a heating block installed on the bottom reflective surface, and a signal control processing circuit device;

[0007] Each transducer reflector cup assembly is a transducer equipped with a reflector cup structure, the mouth of the reflector cup faces the bottom reflective surface, wherein the surface shape of the reflector cup is such that the ultrasonic wave emitted by the transducer to the inner surface of the reflector cup is collimated and reflected by the bottom reflective surface to the transducer at a corresponding position;

[0008] The temperature and humidity sensor is used to measure the temperature and humidity of the bottom reflective surface. When the surface humidity or temperature is lower than a preset value, the heating block is started to heat the bottom reflective surface so that the bottom reflective surface is always kept dry.

[0009] The signal control processing circuit device is used to process the ultrasonic signal and calculate the wind speed and wind direction.

[0010] Furthermore, the top structure adopts an outwardly expanded and widened brim structure.

[0011] Furthermore, the bottom reflective surface adopts an elliptical concave structure, and the transducer reflective cup assembly is installed at the focus of the elliptical surface, so that the ultrasonic wave emitted by the transducer at one focus to the bottom reflective surface can be reflected to the transducer at another focus in a relative position.

[0012] Furthermore, the signal control processing circuit device includes: a temperature and humidity acquisition module, a heating output module, a transducer PWM signal excitation module, a transducer signal receiving module, a signal amplification module, a signal bandpass filtering module, an ADC acquisition module, a microcontroller module and a power system module;

[0013] The temperature and humidity acquisition module is used to transmit the temperature data and humidity data detected by the temperature and humidity sensor to the microcontroller module;

[0014] The heating output module is used to drive the heating block under the PWM control of the microcontroller module;

[0015] The transducer PWM signal excitation module is used to drive the transducer to emit ultrasonic waves by boosting the PWM excitation signal output by the microcontroller module through a transformer;

[0016] The transducer signal receiving module is used to receive the signal through the corresponding analog circuit and transmit it to the signal amplifying module;

[0017] The signal amplification module is used to dynamically adjust the gain of the received signal and then pass it to the signal bandpass filtering module;

[0018] The signal bandpass filter module is used to filter the received signal and then pass it to the external ADC acquisition module;

[0019] The microcontroller module is interconnected with the ADC acquisition module through a peripheral interface, reads the processed ultrasonic signal, and calculates the wind speed and wind direction according to the ultrasonic signal;

[0020] The power system module is used to convert the input voltage into the working voltage required by other modules to supply power to them.

[0021] Furthermore, the signal amplification module is composed of a plurality of programmable gain amplifier integrated circuits connected in series, so as to realize multi-stage controllable amplification of signal strength.

[0022] Furthermore, the microcontroller module calculates the wind speed and wind direction according to the ultrasonic signal, specifically including:

[0023] The four sets of transducer reflector cup combinations in the east, west, south and north are respectively recorded as the first channel to the fourth channel;

[0024] Step 1, the microcontroller module generates a PWM excitation signal to excite the transducer of the first channel to generate ultrasonic waves, and the circulator of the second channel opposite thereto collects ultrasonic signal data of the first channel;

[0025] Step 2, the microcontroller module performs signal gain adaptive processing, filtering and cross-correlation calculation on the collected ultrasonic signal data of the first channel, and records the propagation time;

[0026] Step 3: Repeat steps 1 and 2 until the preset number of acquisitions is reached, and then average all propagation times to obtain the final propagation time t ew ;

[0027] Step 4: For the second to fourth channels, execute steps 1 to 3 respectively to obtain the corresponding final propagation time t we ,t sn ,t ns ;

[0028] Step 5: Based on the propagation time obtained above, the wind speed and wind direction are calculated by the time difference method.

[0029] Furthermore, the signal gain adaptive processing in step 2 specifically adopts a signal gain adaptive adjustment algorithm based on a binary search method, and the algorithm specifically includes:

[0030] Determine whether the maximum value of the ultrasonic signal data is greater than the set upper threshold value. If it is greater than the upper threshold value, the microcontroller module sets the programmable gain amplifier amplification factor to (current factor - lower limit factor) / 2, and then the microcontroller module stimulates the transmission and reception of ultrasonic waves again, and repeats the above process; if it is less than the upper threshold value, execute the next step;

[0031] Determine whether the minimum value of the ultrasonic signal data is less than the set lower threshold value. If it is less than the lower threshold value, the microcontroller module sets the programmable gain amplifier amplification factor to (upper limit factor - current factor) / 2, and then the microcontroller module stimulates the transmission and reception of ultrasonic waves again, and repeats the above process; if it is greater than the lower threshold value, the ultrasonic signal data is used for wind speed calculation.

[0032] Furthermore, the step 5 calculates the wind speed and wind direction by the time difference method based on the propagation time obtained above, specifically including:

[0033] (1) Calculate the wind speed v as:

[0034]

[0035] Among them, v x 、v y They are the wind speed in the east-west direction and the wind speed in the north-south direction respectively;

[0036]

[0037]

[0038] Where, L is the distance between two transducers with opposite positions;

[0039] (2) Calculate wind direction θ:

[0040]

[0041] Compared with the prior art, the present invention has the following significant advantages:

[0042] (1) The transducer reflector cup combination structure proposed in the present invention can perform secondary adjustment on the directional angle of the ultrasonic wave lobe emitted by the transducer, thereby reducing the directional angle of the lobe and making the ultrasonic wave energy more concentrated. The signal strength received by the transducer at the receiving end is stronger, and the signal will not be drowned in the noise in strong wind conditions, so the wind speed and direction can be calculated effectively and accurately.

[0043] (2) The present invention proposes to install the transducer reflector cup on the top plane of the structure with the cup mouth facing the bottom plane, and use the bottom plane as the reflective surface. The rain-shielding property of the reflector cup itself is utilized to prevent water accumulation and ice from forming on the transducer surface, thereby improving the accuracy of measurement in windy and rainy weather.

[0044] (3) The reflecting surface designed in the present invention is an elliptical surface, and the transducer reflecting cup is installed at the focus of the ellipse. By utilizing the geometric characteristics of the ellipse, the ultrasonic wave incident on the elliptical reflecting surface can always be reflected to the receiving transducer end at another focus, thereby reducing the influence of the installation angle deviation on the received signal strength.

[0045] (4) The present invention adopts a combination of a temperature and humidity sensor and a heating block to dynamically heat the reflecting surface through the heating block, so that its surface is always kept in a dry state, thereby preventing water vapor or water droplets on the reflecting surface from affecting the reflection of ultrasonic waves.

[0046] (5) The top of the ultrasonic anemometer of the present invention adopts an outward-expanding and widened brim structure to prevent rain from falling onto the reflecting surface.

[0047] (6) The present invention proposes a wind speed and direction calculation algorithm based on a combination of a cross-correlation method, a three-point five-order smoothing filter method, a ringing method and a time difference method, which can eliminate the influence of ambient temperature on the wind speed and direction calculation and has the ability to resist random noise.

[0048] (7) The present invention proposes for the first time a signal gain adaptive adjustment control algorithm based on the binary search method, which can overcome the problems of low wind speed and direction measurement accuracy and low stability caused by the reduction of sound wave intensity emitted by the ultrasonic transducer and the reduction of sensitivity of the received signal when the traditional ultrasonic anemometer works in rainy and snowy weather, strong wind weather, dusty environment and long-term use, and has strong anti-interference ability.

[0049] The present invention is further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 Schematic diagram of the structure of an ultrasonic wind speed and direction measuring device in one embodiment.

[0051] Figure 2 It is a schematic diagram of a reflective cup in one embodiment that enables the ultrasonic waves emitted by the transducer to the inner surface of the reflective cup to be collimated and emitted.

[0052] Figure 3 It is a schematic diagram of an embodiment in which an ultrasonic wave incident on an elliptical reflecting surface is reflected to a receiving transducer end at another focus.

[0053] Figure 4 FIG. 4 is a schematic diagram of a programmable gain amplifier circuit in an embodiment.

[0054] Figure 5 FIG. 4 is a flow chart of a signal gain adaptive adjustment algorithm in one embodiment.

[0055] Figure 6 FIG. 4 is a schematic diagram of cross-correlation calculation in an embodiment.

[0056] Figure 7 The figure is a schematic diagram of the flow of calculating wind speed and wind direction in one embodiment.

[0057] Figure 8 This is a comparison diagram of the pointing angles of an embodiment without a reflector cup and with a reflector cup, wherein Figure 8(a) is a schematic diagram of the pointing angle without a reflector cup. Figure 8 (b) is a schematic diagram of configuring the pointing angle of the reflector cup.

[0058] Fig. 9 It is a schematic diagram of ultrasonic data collected at zero wind speed in one embodiment.

[0059] Fig.10 The figure is a schematic diagram of ultrasonic data collected in windy conditions in one embodiment.

[0060] Fig.11 In one embodiment, Fig. 9 and Fig.10 Schematic diagram of the cross-correlation spectrum obtained by cross-correlation calculation of the data.

[0061] Fig.12 : is a comparison diagram of signal strengths at different gains at a wind speed of 17 m / s in one embodiment, wherein Fig.12 (a) is a schematic diagram of signal strength using a signal gain adaptive adjustment algorithm based on a binary search method to adjust the gain. Fig.12 (b) is a schematic diagram of signal strength without using the algorithm of the present invention and with fixed gain. Fig.12 (c) is a schematic diagram of signal strength under zero wind speed. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0063] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0064] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0065] In one embodiment, in combination Figure 1 , provides an ultrasonic wind speed and direction measuring device, the device comprising a top structure, four sets of transducer reflector cups mounted on the lower surface of the top structure, namely, east, west, south and north, a bottom reflective surface, a temperature and humidity sensor and a heating block mounted on the bottom reflective surface, and a signal control processing circuit device;

[0066] Each transducer reflector cup assembly is a transducer equipped with a reflector cup structure, the mouth of the reflector cup faces the bottom reflective surface, wherein the surface of the reflector cup should allow the ultrasonic wave emitted by the transducer to the inner surface of the reflector cup to be collimated and reflected by the bottom reflective surface to the transducer at the opposite position, such as Figure 2 As shown; here, the reflector cup uses the reflection law and iterative deduction relationship to calculate the surface data of the reflector cup, which reduces the pointing angle compared to the transducer without the reflector cup structure;

[0067] The temperature and humidity sensor is used to measure the temperature and humidity of the bottom reflective surface. When the surface humidity or temperature is lower than a preset value, the heating block is started to heat the bottom reflective surface so that the bottom reflective surface is always kept dry.

[0068] The signal control processing circuit device is used to process the ultrasonic signal and calculate the wind speed and wind direction.

[0069] Preferably, in some embodiments, the top structure adopts an outwardly expanded and widened brim structure.

[0070] Preferably, in some embodiments, the bottom reflective surface adopts an elliptical concave structure, and the transducer reflective cup assembly is installed at the focus of the elliptical surface, and the geometric characteristics of the ellipse and the reversible principle of the propagation path are utilized so that the ultrasonic wave emitted by the transducer at one focus to the bottom reflective surface can be reflected to the transducer at another focus at a relative position, such as Figure 3 shown.

[0071] Further, in one of the embodiments, the signal control processing circuit device includes: a temperature and humidity acquisition module, a heating output module, a transducer PWM signal excitation module, a transducer signal receiving module, a signal amplification module, a signal bandpass filtering module, an ADC acquisition module, a microcontroller module and a power system module;

[0072] The temperature and humidity acquisition module is used to transmit the temperature data and humidity data detected by the temperature and humidity sensor to the microcontroller module;

[0073] The heating output module is used to drive the heating block under the PWM control of the microcontroller module;

[0074] The transducer PWM signal excitation module is used to drive the transducer to emit ultrasonic waves by boosting the PWM excitation signal output by the microcontroller module through a transformer;

[0075] The transducer signal receiving module is used to receive the signal through the corresponding analog circuit and transmit it to the signal amplifying module;

[0076] The signal amplification module is used to dynamically adjust the gain of the received signal and then pass it to the signal bandpass filtering module;

[0077] The signal bandpass filter module is used to filter the received signal and then pass it to the external ADC acquisition module;

[0078] The microcontroller module is interconnected with the ADC acquisition module through a peripheral interface, reads the processed ultrasonic signal, and calculates the wind speed and wind direction according to the ultrasonic signal;

[0079] The power system module is used to convert the input voltage into the working voltage required by other modules to supply power to them.

[0080] Preferably, in some embodiments, the signal amplification module is composed of a plurality of programmable gain amplifier integrated circuits connected in series, such as Figure 4 As shown, multi-stage controllable amplification of signal strength can be achieved.

[0081] Preferably, in some embodiments, the amplification factor of the programmable gain amplifier is adjusted by a signal gain adaptive adjustment algorithm based on a binary search method integrated in a microcontroller module.

[0082] The microcontroller module reads the ADC conversion data of the ultrasonic signal. Figure 5 , the signal gain adaptive adjustment algorithm based on the binary search method specifically includes:

[0083] Determine whether the maximum value of the signal data is greater than the set upper threshold value. If it is greater than the upper threshold value, the microcontroller module sets the programmable gain amplifier amplification factor to (current factor - lower limit factor) / 2, and then the microcontroller module stimulates the transmission and reception of ultrasonic waves again, and repeats the above process; if it is less than the upper threshold value, execute the next step;

[0084] Determine whether the minimum value of the signal data is less than the set lower threshold value. If it is less than the lower threshold value, the microcontroller module sets the programmable gain amplifier amplification factor to (upper limit factor - current factor) / 2, and then the microcontroller stimulates the transmission and reception of ultrasonic waves again, repeating the above process; if it is greater than the lower threshold value, the signal data is used to calculate the wind speed.

[0085] Further, in one embodiment, in combination Figure 7 The microcontroller module calculates the wind speed and wind direction according to the ultrasonic signal, specifically including:

[0086] The four sets of transducer reflector cup combinations in the east, west, south and north are respectively recorded as the first channel to the fourth channel;

[0087] Step 1, the microcontroller module generates a PWM excitation signal to excite the transducer of the first channel to generate ultrasonic waves, and the circulator of the second channel opposite thereto collects ultrasonic signal data of the first channel;

[0088] Step 2, the microcontroller module performs signal gain adaptive processing, filtering and cross-correlation calculation on the collected ultrasonic signal data of the first channel, and records the propagation time;

[0089] Step 3: Repeat steps 1 and 2 until the preset number of acquisitions is reached, and then average all propagation times to obtain the final propagation time t ew ;

[0090] Step 4: For the second to fourth channels, execute steps 1 to 3 respectively to obtain the corresponding final propagation time t we ,t sn ,t ns ;

[0091] Step 5: Based on the propagation time obtained above, the wind speed and wind direction are calculated by the time difference method.

[0092] Here, the ring method is used to calculate the ultrasonic propagation time. The propagation time with the wind and against the wind is very small, and it is very difficult to measure accurately. This tiny amount of time will be submerged in the measurement error. Multiple measurements of the tiny amount of time are taken, and the time is accumulated continuously. The total amount is then averaged to eliminate the measurement error.

[0093] Further, in one embodiment, the signal gain adaptive processing in step 2 specifically adopts a signal gain adaptive adjustment algorithm based on a binary search method, and the algorithm specifically includes:

[0094] Determine whether the maximum value of the ultrasonic signal data is greater than the set upper threshold value. If it is greater than the upper threshold value, the microcontroller module sets the programmable gain amplifier amplification factor to (current factor - lower limit factor) / 2, and then the microcontroller module stimulates the transmission and reception of ultrasonic waves again, and repeats the above process; if it is less than the upper threshold value, execute the next step;

[0095] Determine whether the minimum value of the ultrasonic signal data is less than the set lower threshold value. If it is less than the lower threshold value, the microcontroller module sets the programmable gain amplifier amplification factor to (upper limit factor - current factor) / 2, and then the microcontroller module stimulates the transmission and reception of ultrasonic waves again, and repeats the above process; if it is greater than the lower threshold value, the ultrasonic signal data is used for wind speed calculation.

[0096] Further, in one embodiment, the step 5 of calculating the wind speed and wind direction by the time difference method based on the propagation time obtained above specifically includes:

[0097] (1) Calculate the wind speed v as:

[0098]

[0099] Among them, v x 、v y They are the wind speed in the east-west direction and the wind speed in the north-south direction respectively;

[0100]

[0101] Where, L is the distance between two transducers with opposite positions;

[0102] (2) Calculate wind direction θ:

[0103]

[0104] Preferably, in some embodiments, in step 2, a five-point cubic smoothing filter method is used to filter the collected ultrasonic signal data to smooth the waveform of the discrete signal and reduce the impact of noise. It uses a specific combination of weighting coefficients to perform weighted averaging on the signal to achieve a smoothing effect.

[0105] Preferably, in some embodiments, in step 2, the Fourier transform method is used to perform cross-correlation calculation, and Fourier transform FFT is performed on the signals x and y respectively, and then the convolution of the two signals in the time domain is converted into the product in the frequency domain, and finally the frequency domain product result is inverse Fourier transformed to obtain the cross-correlation result, as shown in detail. Figure 6 shown.

[0106] As a specific example, in one of the embodiments, the present invention is further verified and explained.

[0107] In this embodiment, the transducer uses an ultrasonic transducer with a center frequency of 200kHz and a directional angle of 22°. A reflective cup surface is designed according to the directional angle range to achieve compression of the directional angle. The comparison effect is as follows: Figure 8Install the four sets of transducer reflector cups in the east, west, south and north directions on the top of the ultrasonic anemometer, with an installation angle of 45° and all pointing to the center of the top structure, as shown. Figure 1 As shown, the temperature and humidity sensor probe and the heating block are installed at the bottom, and the bottom reflective surface is designed to be an elliptical concave surface. The signal control processing circuit device is mainly composed of a temperature and humidity acquisition module, a heating output module, a transducer PWM signal excitation module, a transducer signal receiving module, a signal amplification module, a signal bandpass filtering module, an ADC acquisition module, a microcontroller module and a power system module. The temperature and humidity acquisition module is responsible for transmitting the temperature data and humidity data detected by the temperature and humidity sensor back to the microcontroller, the heating output module drives the heating block under the PWM control of the microcontroller, the transducer PWM signal excitation module is responsible for driving the transducer to emit ultrasonic waves through a transformer boosting the PWM excitation signal output by the microcontroller, the transducer signal receiving module receives the signal through the corresponding analog circuit, and transmits it to the signal amplification module, the signal amplification module dynamically adjusts the gain of the signal, and transmits it to the signal bandpass filtering module, the signal bandpass filtering module filters the signal, and then transmits it to the external high-speed ADC acquisition module, the microcontroller is interconnected with the external ADC through the peripheral interface, and reads the processed ultrasonic signal, and the power system module is used to convert the input voltage into the working voltage required by each submodule to supply power for it.

[0108] The key components include, but are not limited to, the STM32F429 series or other high-frequency processors for the microcontroller, the parallel port AD9280 for the ADC acquisition module, the LTC6910 for the gain amplifier, and the MAX275AEWP for the bandpass filter. The microcontroller generates PWM to excite the transducer of the first channel to generate ultrasonic waves, selects the relative transducer to collect the ultrasonic signal data generated by the transducer of the first channel, and after the collection is completed, performs signal gain adaptive processing, filtering, and cross-correlation calculation on the collected first channel data, records the propagation time, and then repeats the above process until the set number of collections is executed, that is, the ringing method conditions are met, and the remaining second, third, and fourth channels are executed according to the above first channel process, and finally the time difference method is executed to calculate the wind speed and wind direction; the propagation time is mainly calculated by the cross-correlation method. The specific execution process is to collect ultrasonic data with zero wind speed as the standard reference data. The collected data is as follows: Fig. 9 As shown, ultrasonic data is then collected in the presence of wind. The collected data is as follows Fig.10 As shown in FIG, the data collected under zero wind speed and the data collected under wind speed are cross-correlated and the cross-correlation spectrum is obtained, as shown in FIG. Fig.11 As shown, the relative offset is obtained by finding the position of the maximum value of the cross-correlation spectrum. The transmission time of the ultrasonic wave in the windy condition can be obtained according to the relative offset and the ultrasonic wave transmission time at zero wind speed. Fig.12It shows the gain adjustment using the signal gain adaptive adjustment algorithm based on the binary search method at a wind speed of 17m / s and the fixed gain without using the algorithm. The microcontroller reads the ultrasonic signal strength data. The results show that the signal strength using the signal gain adaptive adjustment algorithm based on the binary search method is basically consistent with that at zero wind speed, ensuring that the signal strength is within a reasonable range, which is conducive to the calculation of wind speed and direction.

[0109] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An ultrasonic wind speed and direction measuring device, characterized in that: The device comprises a top structure, four sets of transducer reflector cups mounted on the lower surface of the top structure, namely, east, west, south and north, a bottom reflective surface, a temperature and humidity sensor and a heating block mounted on the bottom reflective surface, and a signal control processing circuit device; Each transducer reflector cup assembly is a transducer equipped with a reflector cup structure, the mouth of the reflector cup faces the bottom reflective surface, wherein the surface shape of the reflector cup is such that the ultrasonic wave emitted by the transducer to the inner surface of the reflector cup is collimated and reflected by the bottom reflective surface to the transducer at a corresponding position; The temperature and humidity sensor is used to measure the temperature and humidity of the bottom reflective surface. When the surface humidity or temperature is lower than a preset value, the heating block is started to heat the bottom reflective surface so that the bottom reflective surface is always kept dry. The signal control processing circuit device is used to process the ultrasonic signal and calculate the wind speed and wind direction.

2. The ultrasonic wind speed and direction measuring device according to claim 1, characterized in that: The top structure adopts an outwardly expanded and widened brim structure.

3. The ultrasonic wind speed and direction measuring device according to claim 1, characterized in that: The bottom reflective surface adopts an elliptical concave structure, and the transducer reflective cup assembly is installed at the focus of the elliptical surface, so that the ultrasonic wave emitted by the transducer at one focus to the bottom reflective surface can be reflected to the transducer at another focus at a relative position.

4. The ultrasonic wind speed and direction measuring device according to claim 1, characterized in that: The signal control processing circuit device includes: a temperature and humidity acquisition module, a heating output module, a transducer PWM signal excitation module, a transducer signal receiving module, a signal amplification module, a signal bandpass filtering module, an ADC acquisition module, a microcontroller module and a power system module; The temperature and humidity acquisition module is used to transmit the temperature data and humidity data detected by the temperature and humidity sensor to the microcontroller module; The heating output module is used to drive the heating block under the PWM control of the microcontroller module; The transducer PWM signal excitation module is used to drive the transducer to emit ultrasonic waves by boosting the PWM excitation signal output by the microcontroller module through a transformer; The transducer signal receiving module is used to receive the signal through the corresponding analog circuit and transmit it to the signal amplifying module; The signal amplification module is used to dynamically adjust the gain of the received signal and then pass it to the signal bandpass filtering module; The signal bandpass filter module is used to filter the received signal and then pass it to the external ADC acquisition module; The microcontroller module is interconnected with the ADC acquisition module through a peripheral interface, reads the processed ultrasonic signal, and calculates the wind speed and wind direction according to the ultrasonic signal; The power system module is used to convert the input voltage into the working voltage required by other modules to supply power to them.

5. The ultrasonic wind speed and direction measuring device according to claim 4, characterized in that: The signal amplification module is composed of a plurality of programmable gain amplifier integrated circuits connected in series, so as to realize multi-stage controllable amplification of signal strength.

6. The ultrasonic wind speed and direction measuring device according to claim 1, characterized in that: The microcontroller module calculates the wind speed and wind direction according to the ultrasonic signal, specifically including: The four sets of transducer reflector cup combinations in the east, west, south and north are respectively recorded as the first channel to the fourth channel; Step 1, the microcontroller module generates a PWM excitation signal to excite the transducer of the first channel to generate ultrasonic waves, and the circulator of the second channel opposite thereto collects ultrasonic signal data of the first channel; Step 2, the microcontroller module performs signal gain adaptive processing, filtering and cross-correlation calculation on the collected ultrasonic signal data of the first channel, and records the propagation time; Step 3: Repeat steps 1 and 2 until the preset number of acquisitions is reached, and then average all propagation times to obtain the final propagation time t ew ; Step 4: For the second to fourth channels, execute steps 1 to 3 respectively to obtain the corresponding final propagation time t we ,t sn ,t ns ; Step 5: Based on the propagation time obtained above, the wind speed and wind direction are calculated by the time difference method.

7. The ultrasonic wind speed and direction measuring device according to claim 5 or 6, characterized in that: The signal gain adaptive processing in step 2 specifically adopts a signal gain adaptive adjustment algorithm based on a binary search method, and the algorithm specifically includes: Determine whether the maximum value of the ultrasonic signal data is greater than the set upper threshold value. If it is greater than the upper threshold value, the microcontroller module sets the programmable gain amplifier amplification factor to (current factor - lower limit factor) / 2, and then the microcontroller module stimulates the transmission and reception of ultrasonic waves again, and repeats the above process; if it is less than the upper threshold value, execute the next step; Determine whether the minimum value of the ultrasonic signal data is less than the set lower threshold value. If it is less than the lower threshold value, the microcontroller module sets the programmable gain amplifier amplification factor to (upper limit factor - current factor) / 2, and then the microcontroller module stimulates the transmission and reception of ultrasonic waves again, and repeats the above process; if it is greater than the lower threshold value, the ultrasonic signal data is used for wind speed calculation.

8. The ultrasonic wind speed and direction measuring device according to claim 6, characterized in that: Step 5, based on the propagation time obtained above, calculates the wind speed and wind direction by the time difference method, specifically including: (1) Calculate the wind speed v as: Among them, v x 、v y They are the wind speed in the east-west direction and the wind speed in the north-south direction respectively; Where, L is the distance between two transducers with opposite positions; (2) Calculate wind direction θ:

9. The ultrasonic wind speed and direction measuring device according to claim 6, characterized in that: In step 2, the collected ultrasonic signal data is filtered using a five-point cubic smoothing filter method.

10. The ultrasonic wind speed and direction measuring device according to claim 6, characterized in that: In step 2, the Fourier transform method is used to perform cross-correlation calculation.

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