A micro ultrasonic anemometer that can be mounted on a drone

Abstract

The application discloses a micro ultrasonic wind speed and direction instrument capable of being carried on a unmanned aerial vehicle and applied to the field of measurement, and through the cooperative work of a comparator, an analog-digital converter and a main control chip, the accurate measurement of wind speed and direction is completed, real-time monitoring of a shielding object of a reflecting surface is realized, timely discovery and early warning are facilitated, and in addition, when the shielding discrimination is established, the instrument body is moved to a lower washing airflow area below the rotor through a mechanical swing arm, the probe and the reflecting surface are washed in the air, the instrument body does not need to be cleaned after landing, the measurement accuracy and the continuous measurement endurance time are improved, and in addition, through the cooperation of the mechanical swing arm and the main control chip, the instrument body is suspended at different positions in the lower washing airflow area and in different postures, the probe and the reflecting surface are directly washed at different positions, the shielding object is separated quickly, and the washing is more sufficient and thorough.

Description

Technical Field

[0001] This invention relates to the field of measurement, and in particular to a miniature ultrasonic anemometer that can be mounted on a drone. Background Technology

[0002] With the widespread application of UAV technology in meteorological monitoring, environmental surveying, and low-altitude economic fields, the demand for airborne miniature meteorological sensing equipment is increasing. Traditional anemometers are difficult to integrate into lightweight UAV platforms due to size and weight limitations. Existing MEMS (microelectromechanical systems) sensors are susceptible to electromagnetic interference in complex airflow environments and suffer from data drift problems, making it difficult to meet the requirements of high-precision dynamic measurement. Against this backdrop, miniaturized anemometers have emerged. This technology calculates wind speed vectors by measuring the time difference of ultrasonic waves propagating in the air with and against the current, and has advantages such as no rotating parts, fast response speed, and low start-up wind speed.

[0003] A patent application with publication number CN110146721B discloses an easy-to-install shockproof ultrasonic anemometer. By setting up a top cover with angle markings, a lower base, a weather rod, and a quick-installation assembly including a limiting sliding block and a limiting sliding groove, the instrument can be quickly disassembled and assembled without tools, improving installation efficiency. At the same time, by setting up a double-layer buffer limiting plate composed of rubber shock-absorbing pads and metal side plates bonded together, a shock absorption and buffering function is achieved, effectively reducing the vibration caused by strong wind impact, protecting internal components, and ensuring long-term stable operation of the instrument.

[0004] The existing patent application with publication number CN202057672U discloses an ultrasonic wind direction and speed meter, which includes a measurement and control system, two sets of ultrasonic probes and a fixed base equipped with an electric heating device. By fixing four ultrasonic probes to four vertical pipes respectively and using an upper disc to block snow, and setting electric heating devices in both the vertical pipes and the upper and lower discs, the overall structure achieves anti-freezing heating function, effectively preventing key components from freezing and forming an ice cover, avoiding changes in the wind field, and thus ensuring the accuracy of wind direction and speed measurement in cold seasons.

[0005] The aforementioned prior art discloses a technical solution for shock absorption and buffering by using a double-layer buffer limiting plate made of rubber shock-absorbing pads and metal side plates bonded together. It also discloses a technical solution for antifreeze and de-icing by using a heating device set in the disc and column. However, the prior art still has shortcomings. The existing miniature ultrasonic anemometer cannot detect the obstruction of the reflective surface in time, and manual cleaning is required after the drone lands. Summary of the Invention

[0006] The core of this invention lies in solving the problem in the prior art that the instrument's reflective surface cannot be detected and dealt with in a timely manner when it is blocked by the occlusion discrimination module and the mechanical swing arm. At the same time, the mechanical swing arm and the main control chip work together to enable the instrument to change its attitude and hover in the downwash airflow zone, thereby improving the airflow flushing effect.

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A miniature ultrasonic anemometer that can be mounted on a drone includes an instrument body, which is installed upside down directly below the drone body. A mechanical swing arm is fixedly connected to the upper end of the instrument body, and the upper end of the mechanical swing arm is fixedly connected to the drone body shell. The mechanical swing arm is used to move the instrument body from directly below the drone body to directly below the rotor.

[0009] The instrument body includes a cylindrical base, with a reflector fixedly connected to the lower end of the base via multiple connecting posts. Multiple probes evenly distributed in a circle are fixedly connected to the base, with the probes' detection ends facing the reflector. The input end of the probe is electrically connected to an ultrasonic drive module, and the input end of the ultrasonic drive module is electrically connected to a main control chip. The output end of the probe is electrically connected to a multiplexer, and the output end of the multiplexer is electrically connected to an amplifier. The output ends of the amplifier are respectively connected to a comparator and an analog-to-digital converter. The output ends of the comparator and the analog-to-digital converter are both electrically connected to the main control chip. The output end of the main control chip is also electrically connected to a mechanical swing arm.

[0010] The main control chip is equipped with a wind speed and direction calculation module, an obstruction detection module, a rinsing execution module, and an early warning module. The obstruction detection module is used to determine whether there is obstruction on the probe surface and the reflective surface of the reflector. The rinsing execution module is electrically connected to the mechanical swing arm and is used to control the swinging action of the mechanical swing arm. The early warning module is used to send obstruction warning signals to the UAV control terminal.

[0011] Furthermore, the occlusion discrimination module includes an echo amplitude comparison unit and a signal-to-noise ratio (SNR) calculation and comparison unit. The echo amplitude comparison unit is used to extract the amplitude information of the echo signal and compare the extracted echo amplitude with the factory-calibrated amplitude. The SNR calculation and comparison unit calculates the SNR based on the extracted echo signal energy and the noise floor energy and compares it with a preset SNR threshold.

[0012] Furthermore, the main control chip, ultrasonic drive module, multiplexer, amplifier, comparator, and analog-to-digital converter are all mounted on the same main control circuit board, which is located inside the cylinder and fixedly connected to the inner wall of the cylinder.

[0013] Furthermore, multiple probes are electrically connected to the main control circuit board, and the probe's detection end extends to the end face of the cylinder base.

[0014] Furthermore, both the reflector and the base are made of stainless steel. A heating block is fixedly connected to the side of the reflector and the base away from the reflective surface. The heating block is used to heat the part of the reflector and the base that is close to the reflective surface. The heating block is electrically connected to the main control chip.

[0015] Furthermore, the mechanical swing arm includes a mounting base, a rotating shaft rotatably connected to the lower end of the mounting base, a swing rod fixedly connected to the rotating shaft, the lower end of the swing rod fixedly connected to the cylinder base, the rotating shaft extending into the mounting base and fixedly connected to a worm gear, the worm gear meshing with a worm, the upper end of the worm fixedly connected to the output shaft of a motor, and the motor housing fixedly connected to the inner wall of the mounting base.

[0016] Furthermore, the mounting base has a hollow cylindrical structure, and its lower part has a strip-shaped groove for accommodating the swing rod, which has a round rod structure.

[0017] Furthermore, the mechanical swing arm is fixed at the center symmetry point of a pair of symmetrically arranged rotors, and a Hall sensor for monitoring the rotational position of the motor output shaft is installed inside the motor. The Hall sensor is electrically connected to the main control chip.

[0018] Compared with the prior art, the advantages of this invention are:

[0019] (1) This invention achieves accurate measurement of wind speed and direction and real-time monitoring of pollutant obstruction by working together with a comparator, analog-to-digital converter and main control chip. No additional hardware is required, simplifying the hardware structure and improving the stability and reliability of the system. In addition, by using a mechanical swing arm, when the obstruction is detected, the instrument body is moved to the downwash airflow area under the rotor. The downwash airflow is used to flush the surface of the probe base and the reflective surface of the reflector plate. There is no need to clean the drone after it lands, thereby improving the measurement accuracy and continuous measurement endurance of the miniature ultrasonic anemometer.

[0020] (2) The present invention uses the mechanical swing arm and the main control chip to make the instrument body hover at different positions in the downwash airflow zone below the rotor, so that the airflow directly washes different positions of the cylinder base and the reflective surface of the reflector, thereby improving the contact effect between the downwash airflow and the reflective surface, thus improving the airflow washing effect. At the same time, by adjusting the attitude of the instrument body in the downwash airflow zone, the dust and water film blocking objects are more likely to detach from the instrument body under the combined action of gravity and airflow blowing force, further improving the cleaning effect. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the installation structure of the instrument body and the UAV body in this invention;

[0022] Figure 2 This is a three-dimensional structural diagram of the instrument body in this invention;

[0023] Figure 3 This is a diagram of the control module of the present invention;

[0024] Figure 4 This is a module diagram of the main control chip in this invention;

[0025] Figure 5 This is a schematic diagram of the instrument body moving into the downwash airflow zone in this invention;

[0026] Figure 6 This is a schematic diagram of a typical beam angle for an ultrasonic probe.

[0027] Figure 7 This is a schematic diagram of the sound field of ultrasound between parallel plates.

[0028] Figure 8 This is a schematic diagram of the probe beam propagation under headwind conditions.

[0029] Figure 9 This is a schematic diagram showing the distribution of the probe on the cylinder base in this invention;

[0030] Figure 10 A schematic diagram showing the decomposition relationship of wind speed in each channel;

[0031] Figure 11 This is a schematic diagram of the assembly structure of the mechanical swing arm and the instrument body in this invention;

[0032] Figure 12 This is a schematic diagram of the internal structure of the mechanical swing arm in this invention;

[0033] Figure 13 This is a schematic diagram showing the hovering of the instrument body at different positions in the downwash airflow zone in this invention;

[0034] Figure 14 This is a schematic diagram showing the contact between the downwash airflow and the instrument body during clockwise rotation in this invention;

[0035] Figure 15 This is a schematic diagram showing the contact between the downwash airflow and the instrument body during counterclockwise rotation in this invention.

[0036] Explanation of the labels in the diagram:

[0037] 1. Instrument body; 2. Mechanical swing arm; 3. UAV body; 4. Rotor; 5. Cylinder base; 503. Left cylinder; 504. Right cylinder; 6. Connecting column; 7. Reflector; 701. Left plate; 702. Right plate; 8. Probe; 9. Mounting base; 10. Swing rod; 11. Rotating shaft; 12. Worm gear; 13. Worm; 14. Motor; 15. Ultrasonic drive module; 16. Main control chip; 17. Multiplexer; 18. Amplifier; 19. Comparator; 20. Analog-to-digital converter. Detailed Implementation

[0038] The technical solutions will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0039] First implementation method

[0040] Please see Figures 1-5 In one embodiment of the present invention, a miniature ultrasonic anemometer that can be mounted on a drone includes an instrument body 1. The instrument body 1 is installed upside down directly below the drone body 3. A mechanical swing arm 2 is fixedly connected to the upper end of the instrument body 1. The upper end of the mechanical swing arm 2 is fixedly connected to the shell of the drone body 3. The mechanical swing arm 2 is used to move the instrument body 1 from directly below the drone body 3 to directly below the rotor 4.

[0041] Please see Figure 1 , Figure 2 and Figure 3 The instrument body 1 includes a cylindrical base 5. A reflector 7 is fixedly connected to the lower end of the cylindrical base 5 through multiple connecting posts 6. Multiple probes 8 are fixedly connected to the cylindrical base 5 in a circumferentially evenly distributed manner, with the detection end of the probe 8 facing the reflector 7. The input end of the probe 8 is electrically connected to an ultrasonic drive module 15, and the input end of the ultrasonic drive module 15 is electrically connected to a main control chip 16. The output end of the probe 8 is electrically connected to a multiplexer 17, and the output end of the multiplexer 17 is electrically connected to an amplifier 18. The output end of the amplifier 18 is connected to a comparator 19 and an analog-to-digital converter 20, respectively. The output ends of the comparator 19 and the analog-to-digital converter 20 are both electrically connected to the main control chip 16. The output end of the main control chip 16 is also electrically connected to the mechanical swing arm 2.

[0042] Please see Figure 3 and Figure 4 The main control chip 16 is equipped with a wind speed and direction calculation module, an obstruction detection module, a rinsing execution module, and an early warning module. The obstruction detection module is used to determine whether there is obstruction on the surface of the probe 8 and the reflective surface of the reflector 7. The rinsing execution module is electrically connected to the mechanical swing arm 2 and is used to control the swinging action of the mechanical swing arm 2. The early warning module is used to send an obstruction early warning signal to the UAV control terminal.

[0043] Specifically, the workflow of the miniature ultrasonic anemometer that can be mounted on a drone is as follows: First, the main control chip 16 outputs a control signal to start the ultrasonic drive module 15. The ultrasonic drive module 15 drives multiple probes 8 to emit ultrasonic signals. The ultrasonic signals propagate in the air and are reflected by the reflector 7. They are then captured by the probes 8 and converted into weak analog echo electrical signals.

[0044] The weak echo signal is first input to the multiplexer 17. Under the control of the main control chip 16, the multiplexer 17 realizes the time-division selection of the echo of the multi-channel probe, and sends the selected echo signal to the amplifier 18 to amplify the weak echo signal to meet the needs of subsequent signal processing.

[0045] The amplified echo signal is transmitted in parallel via two separate paths to perform different signal processing functions:

[0046] One of the echo signals is input to comparator 19. Comparator 19 compares the analog echo signal with a preset threshold voltage. When the amplitude of the echo signal exceeds the threshold, comparator 19 outputs a digital transition edge signal. The wind speed and direction calculation module in the main control chip 16 captures this transition edge through a timer, records the arrival time of the ultrasonic echo, and calculates the propagation time of the ultrasonic wave in the air by combining it with the emission time of the ultrasonic wave, thereby solving the wind speed and direction parameters.

[0047] Another echo signal is input to the analog-to-digital converter 20. The analog-to-digital converter 20 converts the continuous analog echo signal into discrete digital waveform data and transmits this data to the main control chip 16 for digital signal processing. The main control chip 16 analyzes the digital waveform data, extracts the amplitude information of the echo signal, and calculates the ratio of echo signal energy to background noise energy (signal-to-noise ratio, SNR). Combined with preset echo amplitude thresholds and SNR thresholds, it can realize real-time discrimination of whether there are contaminants such as dust, water film, and ice blocking the surface of the probe 8 and the reflective surface of the reflector 7. When the discrimination of obstruction is established, the main control chip 16 activates the mechanical swing arm 2, which moves the instrument body 1 to below the rotor 4 (e.g., Figure 5 As shown in the figure, the downwash airflow generated by the rotor 4 is used to wash the surface of the cylinder base 5 where the probe 8 is located and the reflective surface of the reflector plate 7.

[0048] It should be noted that this instrument is based on the acoustic resonance phase difference method for wind measurement. It calculates wind speed by measuring the change in ultrasonic wave propagation time (i.e., phase change) under tailwind and headwind conditions. For the phase difference method, the ultrasonic probe emits a beam with a certain directionality, and the beam angle θ typically ranges from 0 degrees to 180 degrees (e.g., ...). Figure 6 As shown in the figure, the higher the directivity of the probe, the more concentrated the energy. Traditional ultrasonic anemometers require probes to have a certain tilt angle or be arranged in a cross shape to measure wind speed and direction. This measurement method usually means that the final anemometer will have a large volume, which is not suitable for miniaturized wind measurement.

[0049] The ultrasonic waves emitted by an ultrasonic probe are, in a sense, close to spherical waves. From a two-dimensional perspective, they are beams with a certain radiating surface. When the beam reaches the reflecting surface, it is reflected, forming new wavelets that propagate further forward. The reflected wavelets and the forward-propagating beam interfere with each other. At the points where the waves meet, the sound pressure P of the ultrasonic wave is amplified, while at the points where the waves meet, the sound pressure P is canceled out. The magnitude of the ultrasonic sound pressure is also related to the distance S from the sound source: P = P0 * e -αS Where P0 is the initial sound pressure of the probe, α is the attenuation coefficient, and S is the distance from the sound source.

[0050] exist Figure 7 A spherical sound source was used to simulate the sound field of the parallel plate. The brighter areas in the figure represent areas with stronger sound pressure, while the darker areas represent areas with weaker sound pressure. When the sound source probe emits ultrasonic waves perpendicularly into the parallel plate, most of the ultrasonic waves are reflected by the plate and interfere with the incident ultrasonic waves to form traveling waves that spread to the left and right. The receiving probe measures the traveling waves during the interference process. In actual operation, the beam angle θ emitted by the probe is usually less than 180 degrees. For two probes placed far apart, the ultrasonic wave propagation process is mainly composed of reflected waves, and the direct wave has been attenuated to the point of being negligible.

[0051] When two probes are placed close together, the direct wave will reach the receiving probe before the reflected wave, resulting in multiple receptions of ultrasonic waves. This situation of receiving ultrasonic waves through a short path will prevent the wind speed from being measured normally. Therefore, when using the acoustic resonance method, it is necessary to select an ultrasonic transducer with an appropriate beam angle, and the distance between the transducers should also be appropriate to avoid the situation where ultrasonic waves directly propagate to the probe through the probe as much as possible.

[0052] The ultrasonic probe emits a cylindrical beam with a maximum beam angle typically θ. Ultrasonic anemometers, designed based on the principle of acoustic resonance, usually have multiple ultrasonic propagation paths. Ignoring direct lateral radiation, the beam path that first reaches the receiving probe is S1, and it only requires one reflection. Based on the symmetry of the spherical ultrasonic wave reflected between the electrodes, the distance to S1 and the beam angle θ' at that moment are respectively:

[0053] ; ;

[0054] Where h is the distance between the upper and lower reflecting surfaces (the reflecting surface of the reflector 7 and the reflecting surface of the cylinder base 5 where the probe 8 is located), and d is the distance between the two probes 8.

[0055] Figure 8 In a headwind environment, when the ultrasonic wave travels from probe one along the shortest beam path to probe four, it must overcome not only wind resistance but also angular drift caused by the wind. The entire process takes time t. s1for:

[0056] ;

[0057] When the ambient wind is downwind, the time t required for the ultrasonic wave to travel from probe one to probe four is... s2 for:

[0058] ;

[0059] When there is no wind, the time t required for the ultrasonic wave to travel from probe one to probe four is... s0 for:

[0060] ;

[0061] In the formula, c is the speed of sound of the ultrasound, and v is the wind speed at this time. Ultrasonic waves with a beam angle greater than θ cannot be received by the probe after being reflected by the upper baffle. Ultrasonic signals with a beam angle less than θ will be reflected again by the lower baffle, and a portion of them will be received by the probe. The first reflected ultrasound not only interferes with the direct wave but also with the second reflected ultrasound. The second reflected ultrasound will also interfere with the direct wave and the first reflected ultrasound. Finally, the ultrasonic field in the entire parallel plate cavity is mainly composed of the interference and superposition between the direct ultrasound and the ultrasound reflected multiple times. The ultrasound that can be received by the probe is mainly the ultrasound reflected and interfered with each other. The specific propagation process is very complex and has no solution in the usual sense. However, for ultrasound reflected multiple times, its beam angle is too small, the propagation path is too long, and the attenuation of the sound intensity is negligible. Therefore, the ultrasonic transmission time is mainly determined by the ultrasonic beam that first arrives at the receiving probe. The relationship between the time difference Δt and the phase difference Δφ during the transmission of ultrasound between the plates is as follows:

[0062] ;

[0063] Where f is the ultrasonic frequency, Δφ represents the lead-lag relationship between the ultrasonic signal propagating from probe one through the inter-plate space to probe four and being received, and the transmission time t in the downwind direction can be determined by capturing the falling edge. s2 Shorter, smaller phase, waveform leading, transmission time t in headwind s1 As the length increases, the phase increases, and the waveform lags.

[0064] The probe layout of the miniature ultrasonic anemometer is as follows: Figure 9 As shown, in Figure 9In the probe layout, four probes (defined as probe one, probe two, probe three, and probe four) are all vertically downwards. During wind speed measurement, the phase difference between the ultrasonic waves emitted by probe four and received by probe one is Δφ41; the phase difference between the ultrasonic waves emitted by probe one and received by probe four is Δφ14; the phase difference between the ultrasonic waves emitted by probe four and received by probe three is Δφ43; the phase difference between the ultrasonic waves emitted by probe three and received by probe four is Δφ34; the phase difference between the ultrasonic waves emitted by probe three and received by probe two is Δφ32; the phase difference between the ultrasonic waves emitted by probe two and received by probe three is Δφ23; and finally, probe one emits the ultrasonic waves. The phase difference received by probe two is △φ12, and the phase difference received by probe one from probe two is △φ21. By rotating counterclockwise one full circle, eight sets of phase differences are obtained. Based on the approximate symmetry, four pairs of phase differences related to wind speed and direction information can be obtained, namely △φ21 and △φ12, △φ23 and △φ32, △φ41 and △φ14, and △φ43 and △φ34. In this way, the wind speed value corresponding to each probe can be determined based on the phase shift value measured by the main control chip 16. Then, the wind vector corresponding to each probe is decomposed in the X and Y directions (e.g., Figure 10 (As shown) and sum to obtain V x and V y ,exist Figure 10 In the middle, V 12 V represents the wind speed from probe one to probe two. 41 V represents the wind speed blowing from probe four towards probe one. 43 V represents the wind speed blowing from probe four towards probe three. 32 The wind speed V represents the wind speed blowing from probe three towards probe two. The final wind speed V and wind direction θ are:

[0065] ; .

[0066] Compared to traditional miniature ultrasonic anemometers, this invention, through the collaborative operation of comparator 19, analog-to-digital converter 20, and main control chip 16, achieves both accurate measurement of wind speed and direction and real-time monitoring of pollutant obstruction. This simplifies the hardware structure and improves system stability and reliability without requiring additional hardware. Furthermore, the mechanical swing arm 2 moves the instrument body 1 to the downwash airflow zone below the rotor 4 when obstruction is detected. The downwash airflow then washes the surface of the probe 8's base 5 and the reflective surface of the reflector 7, eliminating the need for post-landing cleaning by the drone. This improves the measurement accuracy and continuous measurement endurance of the miniature ultrasonic anemometer.

[0067] Please see Figure 3 and Figure 4The occlusion detection module includes an echo amplitude comparison unit and a signal-to-noise ratio (SNR) calculation and comparison unit. The echo amplitude comparison unit is used to extract the amplitude information of the echo signal and compare the extracted echo amplitude with the factory-calibrated amplitude. When the real-time amplitude ratio is lower than the ratio threshold, the warning module sends a warning signal to the UAV control terminal. The SNR calculation and comparison unit calculates the SNR based on the extracted echo signal energy and noise floor energy and compares it with the preset SNR threshold. When the real-time SNR is lower than the set SNR threshold, the warning module sends a warning signal to the UAV control terminal.

[0068] Specifically, in actual use, when the reflective surface of the reflector 7 and the reflective surface of the cylinder base 5 are covered or blocked by water film, dust, or ice, the amplitude ratio threshold is set to no more than 45% and the signal-to-noise ratio threshold is set to no more than 16dB. When the real-time amplitude ratio is lower than the amplitude ratio threshold or the real-time signal-to-noise ratio is lower than the signal-to-noise ratio threshold, an early warning is triggered if either condition is met. Using the echo amplitude ratio and signal-to-noise ratio as dual criteria can better adapt to low temperature, icing, strong wind, and high humidity conditions, and effectively reduce the false alarm rate.

[0069] Please see Figure 2 and Figure 3 The main control chip 16, ultrasonic drive module 15, multiplexer 17, amplifier 18, comparator 19, and analog-to-digital converter 20 are all mounted on the same main control circuit board, which is located inside the cylinder base 5 and fixedly connected to the inner wall of the cylinder base 5.

[0070] Specifically, various components are integrated and installed through the main control circuit board to improve integration and maintainability. It should be noted that the main control chip 16 is either an MCU or an FPGA, which can be selected by those skilled in the art as needed.

[0071] Please see Figure 2 Multiple probes 8 are electrically connected to the main control circuit board, and the detection end of the probe 8 extends to the end face of the cylinder base 5.

[0072] Specifically, the probe end of the probe 8 is flush with the end face of the cylinder base 5, which makes the end face of the cylinder base 5 flat. This not only facilitates the reflection of sound waves, but also facilitates airflow rinsing, reducing the residue of dust and moisture.

[0073] In this embodiment, both the reflector 7 and the cylinder base 5 are made of stainless steel. A heating block is fixedly connected to the side of the reflector 7 and the cylinder base 5 away from the reflective surface. The heating block is used to heat the part of the reflector 7 and the cylinder base 5 that is close to the reflective surface. The heating block is electrically connected to the main control chip 16.

[0074] Specifically, when water film, ice, or mud adheres to the reflective surfaces of reflector 7 and cylinder base 5, heating by heating block accelerates water film evaporation, ice melting, and mud drying. Combined with the rinsing of the downwash airflow, it accelerates the removal of moisture and dust, improving the rinsing effect. It should be noted that when the occlusion discrimination module determines the result, the main control chip 16 synchronously starts the heating block.

[0075] Second implementation method

[0076] Based on the first implementation, please refer to Figure 11 and Figure 12 The mechanical swing arm 2 includes a mounting base 9. A rotating shaft 11 is rotatably connected to the lower end of the mounting base 9. A swing rod 10 is fixedly connected to the rotating shaft 11. The lower end of the swing rod 10 is fixedly connected to the cylinder base 5. The rotating shaft 11 extends into the mounting base 9 and is fixedly connected to a worm gear 12. The worm gear 12 meshes with a worm 13. The upper end of the worm 13 is fixedly connected to the output shaft of a motor 14. The housing of the motor 14 is fixedly connected to the inner wall of the mounting base 9.

[0077] Specifically, motor 14 drives worm gear 13 to rotate, worm gear 13 drives worm wheel 12 to rotate, worm wheel 12 drives rotating shaft 11 to rotate, rotating shaft 11 drives swing rod 10 to rotate, and swing rod 10 drives instrument body 1 to rotate to the lower washing airflow zone.

[0078] Please see Figure 11 and Figure 12 The mounting base 9 has a hollow cylindrical structure, and its lower part has a strip-shaped groove for accommodating the swing rod 10, which has a round rod structure.

[0079] Specifically, the cylindrical mounting base 9 and the rod-shaped swing arm 10 both help reduce the wind resistance of the mechanical swing arm 2 and improve the flight stability of the UAV body 3.

[0080] Please see Figure 1 and Figure 12 The mechanical swing arm 2 is fixed at the center symmetry point of a pair of symmetrically arranged rotors 4. A Hall sensor for monitoring the rotation position of the output shaft of the motor 14 is installed inside the motor 14. The Hall sensor is electrically connected to the main control chip 16.

[0081] Specifically, the rotational position of the output shaft of motor 14 is detected by a Hall sensor. Based on the feedback signal from the Hall sensor, the main control chip 16 performs closed-loop control of the rotation angle of motor 14, thereby monitoring the rotational position of the swing arm 10. Since the downwash airflow generated by rotor 4 is vertically downward, a columnar downwash airflow zone is formed in the vertical space where rotor 4 is located. A columnar space is also formed between reflector 7 and cylinder base 5. To improve the washing effect of the downwash airflow on the reflector surfaces of reflector 7 and cylinder base 5, the swing direction and angle of the swing arm 10 are controlled to ensure full contact between the downwash airflow and the reflector surfaces of reflector 7 and cylinder base 5. Please refer to [link to relevant documentation]. Figures 13-15 The specific details are as follows:

[0082] Initially, the instrument body 1 is located in the initial position of the calm wind zone directly below the UAV body 3, the swing rod 10 is in a vertical state, and the following definitions are made: the cylinder base 5 is divided into the left cylinder part 503 and the right cylinder part 504 with the middle vertical plane as the boundary, and the reflector 7 is divided into the left plate part 701 and the right plate part 702 with the middle vertical plane as the boundary.

[0083] In scenario one, the swing arm 10 drives the instrument body 1 to rotate clockwise from a vertical position. When the entire instrument body 1 is fully inside the downwash airflow zone and the clockwise rotation angle is less than 90 degrees, the motor 14 is turned off, causing the instrument body 1 to hover in this position for a set time (10S-30S). This position is called the first hovering position. In the first hovering position, the vertical downwash airflow first contacts the reflective surface of the left plate 701, and then flows out along the gap between the cylinder base 5 and the reflective plate 7.

[0084] In scenario two, the swing rod 10 drives the instrument body 1 to continue rotating clockwise from the first hovering position, causing the swing rod 10 to rotate to a horizontal position, which is the second hovering position. The instrument body 1 hovers in the second hovering position for a set time (10S-30S). At this position, the vertical downward washing airflow enters from the left plate part 701 and the left cylinder part 503 side into the gap between the cylinder seat 5 and the reflector plate 7 for vertical washing.

[0085] In scenario three, the swing arm 10 drives the instrument body 1 to continue rotating clockwise from the second hovering position, so that the instrument body 1 rotates to above the second hovering position and the counterclockwise rotation angle is less than 180 degrees, and ensures that the instrument body 1 is located in the downwash airflow area below the rotor 4. This position is the third hovering position. The instrument body 1 hovers in the third hovering position for a set time (10S-30S). At this position, the vertical downwash airflow first contacts the reflective surface of the left cylinder 503, and then flows out along the gap between the cylinder base 5 and the reflector 7.

[0086] Case 4: The swing rod 10 drives the instrument body 1 to rotate counterclockwise from the vertical position. When the instrument body 1 rotates into the downwash airflow zone (which is symmetrically distributed with the downwash airflow zone reached by the clockwise rotation of the instrument body 1) and the counterclockwise rotation angle is less than 90 degrees, the motor 14 is turned off. At this time, the position of the instrument body 1 is the fourth hovering position. The instrument body 1 hovers in the fourth hovering position for a set time (10S-30S). At this position, the vertical downwash airflow first contacts the right plate 702 and then flows out along the gap between the cylinder base 5 and the reflector 7.

[0087] In scenario 5, the swing rod 10 drives the instrument body 1 to continue rotating counterclockwise from the fourth hovering position, causing the swing rod 10 to rotate to a horizontal position, which is the fifth hovering position. The instrument body 1 hovers in the fifth hovering position for a set time (10S-30S). At this position, the vertical downward washing airflow enters from the right plate part 702 and the right cylinder part 504 side into the gap between the cylinder seat 5 and the reflector plate 7 for vertical washing.

[0088] In scenario six, the swing arm 10 drives the instrument body 1 to continue rotating counterclockwise from the fifth hovering position, so that the instrument body 1 rotates to above the fifth hovering position and the counterclockwise rotation angle is less than 180 degrees, and ensures that the instrument body 1 is located in the downwash airflow area below the rotor 4. This position is the sixth hovering position. The instrument body 1 hovers in the sixth hovering position for a set time (10S-30S). At this position, the vertical downwash airflow first contacts the reflective surface of the right cylinder 504, and then flows out along the gap between the cylinder base 5 and the reflector 7.

[0089] It should be noted that the control logic of the main control chip 16 to control the mechanical swing arm 2 to rotate counterclockwise or clockwise is based on a preset rinsing program or based on real-time environmental wind direction data. The environmental wind direction data means that the mechanical swing arm 2 drives the instrument body 1 to swing in the wind direction first to reduce wind resistance. After rinsing on one side, the UAV body can rotate 180 degrees, so that the original counterclockwise swing can also swing in the wind direction, reducing energy consumption and improving the stability of the rinsing operation.

[0090] Compared to traditional miniature anemometers, this invention, through the cooperation of the mechanical swing arm 2 and the main control chip 16, allows the instrument body 1 to hover at different positions in the downwash airflow zone below the rotor 4. This allows the airflow to directly wash different positions of the cylinder base 5 and the reflective surface of the reflector plate 7, improving the contact effect between the downwash airflow and the reflective surface, thereby enhancing the airflow washing effect. At the same time, by adjusting the attitude of the instrument body 1 within the downwash airflow zone, dust and water film obstructions are more easily detached from the instrument body 1 under the combined action of gravity and airflow blowing force, further improving the cleaning effect.

[0091] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A miniature ultrasonic anemometer / wind vane that can be mounted on a drone, characterized in that: Includes an instrument body (1), which is installed upside down directly below the drone body (3). A mechanical swing arm (2) is fixedly connected to the upper end of the instrument body (1). The upper end of the mechanical swing arm (2) is fixedly connected to the shell of the drone body (3). The mechanical swing arm (2) is used to move the instrument body (1) from directly below the drone body (3) to directly below the rotor (4). The instrument body (1) includes a cylindrical base (5), and a reflector (7) is fixedly connected to the lower end of the cylindrical base (5) through multiple connecting columns (6). Multiple probes (8) are fixedly connected to the cylindrical base (5) in a circumferentially evenly distributed manner, and the detection end of the probe (8) faces the reflector (7). The input end of the probe (8) is electrically connected to an ultrasonic drive module (15), and the input end of the ultrasonic drive module (15) is electrically connected to a main control chip (16). The output end of the probe (8) is electrically connected to a multiplexer (17), and the output end of the multiplexer (17) is electrically connected to an amplifier (18). The output end of the amplifier (18) is connected to a comparator (19) and an analog-to-digital converter (20) respectively. The output ends of the comparator (19) and the analog-to-digital converter (20) are both electrically connected to the main control chip (16). The output end of the main control chip (16) is also electrically connected to a mechanical swing arm (2). The main control chip (16) is equipped with a wind speed and direction calculation module, an obstruction judgment module, a rinsing execution module and an early warning module. The obstruction judgment module is used to determine whether there is obstruction on the surface of the probe (8) and the reflective surface of the reflector (7). The rinsing execution module is electrically connected to the mechanical swing arm (2) and is used to control the swinging action of the mechanical swing arm (2). The early warning module is used to send an obstruction early warning signal to the UAV control terminal.

2. The miniature ultrasonic anemometer and wind vane that can be mounted on a drone according to claim 1, characterized in that: The occlusion discrimination module includes an echo amplitude comparison unit and a signal-to-noise ratio (SNR) calculation and comparison unit. The echo amplitude comparison unit is used to extract the amplitude information of the echo signal and compare the extracted echo amplitude with the factory-calibrated amplitude. The SNR calculation and comparison unit calculates the SNR based on the extracted echo signal energy and the noise floor energy and compares it with a preset SNR threshold.

3. The miniature ultrasonic anemometer and wind vane that can be mounted on a drone according to claim 1, characterized in that: The main control chip (16), ultrasonic drive module (15), multiplexer (17), amplifier (18), comparator (19), and analog-to-digital converter (20) are all mounted on the same main control circuit board, which is located inside the cylinder base (5) and fixedly connected to the inner wall of the cylinder base (5).

4. A miniature ultrasonic anemometer and wind vane that can be mounted on a drone according to claim 3, characterized in that: Multiple probes (8) are electrically connected to the main control circuit board, and the detection end of the probe (8) extends to the end face of the cylinder base (5).

5. A miniature ultrasonic anemometer and wind vane that can be mounted on a drone according to claim 1, characterized in that: The reflector (7) and the cylinder (5) are both made of stainless steel. A heating block is fixedly connected to the side of the reflector (7) and the cylinder (5) away from the reflective surface. The heating block is used to heat the part of the reflector (7) and the cylinder (5) close to the reflective surface. The heating block is electrically connected to the main control chip (16).

6. The miniature ultrasonic anemometer and wind vane that can be mounted on a drone according to claim 1, characterized in that: The mechanical swing arm (2) includes a mounting base (9), a rotating shaft (11) is rotatably connected to the lower end of the mounting base (9), a swing rod (10) is fixedly connected to the rotating shaft (11), the lower end of the swing rod (10) is fixedly connected to the cylinder seat (5), the rotating shaft (11) extends into the mounting base (9) and is fixedly connected to a worm gear (12), the worm gear (12) meshes with a worm (13), the upper end of the worm (13) is fixedly connected to the output shaft of a motor (14), and the outer shell of the motor (14) is fixedly connected to the inner wall of the mounting base (9).

7. A miniature ultrasonic anemometer and wind vane that can be mounted on a drone according to claim 6, characterized in that: The mounting base (9) has a hollow cylindrical structure, and its lower part has a strip groove for accommodating the swing rod (10). The swing rod (10) has a round rod structure.

8. A miniature ultrasonic anemometer and wind vane that can be mounted on a drone according to claim 6, characterized in that: The mechanical swing arm (2) is fixed at the center symmetrical point of a pair of symmetrically arranged rotors (4). A Hall sensor for monitoring the rotation position of the output shaft of the motor (14) is installed inside the motor (14). The Hall sensor is electrically connected to the main control chip (16).

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