Semi-quantitative real-time monitoring unmanned aerial vehicle for wind power and wind quantity at middle

Abstract

The invention relates to a semi-quantitative real-time monitoring unmanned aerial vehicle for medium-low-altitude wind power and wind quantity. The semi-quantitative real-time monitoring unmanned aerial vehicle comprises a rotor unmanned aerial vehicle, a remote controller and a hanging swing belt The rotor unmanned aerial vehicle is connected with the hanging swing belt through the hanging ring below the belly, and a reliable indication platform can be provided for monitoring in any middle and low altitude airspace under a certain wind power condition; according to the hanging pendulum belt, wind power in different sizes and directions is correspondingly indicated through the variable density design, the situation that the hanging pendulum belt is drawn into a rotor wing of the unmanned aerial vehicle is avoided, real-time monitoring of the wind power in the airspace is guaranteed, and then the air volume in the corresponding time period of the airspace is estimated; in addition, the monitoring space-time range can be expanded through an LED upgrading means.

Description

Technical Field

[0001] The invention belongs to a special-function UAV, in particular to a rotor UAV for monitoring wind flow field data in a certain airspace and under certain meteorological conditions. Background Art

[0002] In the troposphere, the average eye can discern the outline of decimeter-level objects at a distance of about 200 to 300 meters, and the distance for discerning centimeter-level object features is within tens of meters, and can exceed kilometers with the help of optical telescopes. When the wind force is level 6, the maximum wind speed is less than 14 meters per second. According to the naked eye's discernible outline distance of 200 meters and the maximum wind speed of level 6, the "remote perception-origin perception" time of the airflow is about 14 seconds. In addition, the wind will also be affected by the nearby pressure field, temperature field, Coriolis force, and even obstacles during the process of flowing through the air flow field, and will undergo significant changes. Therefore, it is difficult for the meteorological department to obtain instantaneous data on wind force in various places, and only predicts a low-precision average value based on the measured data of each sampling point. Existing wind speed and direction instruments and wind pressure gauges can only monitor wind force and volume data at fixed coordinates near the surface. The use of sounding balloons is limited by high costs, large size, and poor flexibility. These devices are difficult to play a role in real-time monitoring of instantaneous wind force in special operations that require visual perception advantages in any airspace.

[0003] Compared with the above equipment, rotorcraft drones have more flexible maneuverability and good stability. As the mainstream model of consumer drones today, quadcopters have main model parameters with maximum wind resistance levels of 5 to 8, maximum flight speeds of around 10 to 39 meters per second, maximum take-off altitudes of 2,500 to 7,000 meters, maximum flight time of around 20 minutes to 1 hour, and maximum flight altitudes of less than 800 meters. These performance parameters will continue to improve with the emergence of new models and new technologies.

[0004] The common optional settings in the peripherals of rotary-wing UAVs include optical flow positioning, satellite positioning, imaging modules, and other electronic control and signal modules. The distribution of the air flow field generated by the rotary-wing UAV during its flight is roughly as follows: a cylindrical area with the rotating circle of each rotor blade as the cross section, downward along the axis of rotation, and the farther away from the blade, the lower the air flow field strength, and there are a large number of eddies in a small area near the blade surface. When the drone is blown by the external wind, its positioning and electronic control modules also have certain performance: the attitude change when the horizontal component of its own airflow field is offset by the external wind by changing the hovering inclination angle changes within the centimeter range, so it is not easy to identify at a long distance; the feedback electrical signal generated when the position change is detected by its positioning module has a step fluctuation state when forming a control closed loop with the motor drive circuit, and its fluctuation error is not easy to be recognized by the remote remote terminal after the signal delay is superimposed; the image signal change transmitted back to the remote control terminal through its imaging module is also difficult to accurately identify due to the image transmission bit rate and the delay of the image transmission system, and considering the accuracy error of the drone's flight altitude to the photographed object, it is even more difficult to perceive the external wind disturbance by the imaging system.

[0005] Through further research and experiments, it was found that: without considering turbulent interference and external wind interference, when the drone is hovering stably, the airflow field strength distribution under the rotor of the drone not only weakens with the increase of the distance from the rotor in the wing axis direction, but also decreases with the increase of distance on each plane perpendicular to the wing axis line below the rotor. Therefore, in three-dimensional space, it presents the field strength characteristics of an inverted cone divergence with the circle where the rotor is located as the base (the closer to the main axis line, the stronger the field strength, the farther from the main axis line, the weaker the field strength; the closer to the rotor, the stronger the field strength, the farther from the rotor, the weaker the field strength, which is the diffusion effect); at the same time, there is a situation where the inverted cone divergence thresholds far away from the main axis lines of each rotor under adjacent rotors overlap with each other. At this time, the field strength that was originally weakened due to the distance from the main axis is strengthened again due to the superposition, and the larger the superposition area of ​​the plane farther from the rotor, until the distance is far enough to cover all the planes of the entire drone. The airflow fields generated by the rotors are superimposed to the point where they are difficult to distinguish (i.e., the superposition effect); however, due to the existence of the diffusion effect, even if this superposition effect strengthens the airflow field in the same vertical main axis plane, the flow field intensity in the planes far away from the rotors still shows a diffusion attenuation effect on the whole - that is, the superposition effect is weaker than the diffusion effect. Therefore, the airflow field intensity conditions generated by the drone itself at equidistant locations between the cylindrical areas under the rotors of each axis described in

[0004] are extremely weak. From the overall perspective of the drone (stable hovering), the airflow fields generated by each rotor are symmetrically distributed on both sides of two planes (two vertical planes) passing through the longitudinal and transverse axes of the drone fuselage and perpendicular to the plane (horizontal plane) where the longitudinal and transverse axes of the drone fuselage are located after diffusion and superposition. These two planes are called "symmetric facades". The greater the angle of deviation from the "symmetric facade" on the vertical plane, the worse the symmetry of the airflow fields generated by each rotor of the drone.

[0006] Through further research and experiments, it was found that when there is external wind, the direction of the airflow field generated by the drone rotor and the external wind airflow field is superimposed, which is tilted to varying degrees toward the external wind direction relative to the airflow field generated by the original drone rotor. That is, the tilt degree is weak at the location where the original drone rotor's own airflow field intensity is high, and the tilt degree is strong at the location where the original drone rotor's own airflow field intensity is low. Therefore, when the drone is blown by the external wind, the direction of the wind field changes weakly at a close distance directly below the rotor, while the direction of the wind field changes significantly at a long distance.

[0007] Since no suitable method for measuring air volume in an open area has been found before, it can only be limited to measuring air volume in a closed channel, that is, "used to indicate the capacity of a blower or ventilation equipment", that is, "instantaneous air volume = instantaneous wind speed × flow cross-sectional area", "observed air volume = sum of all instantaneous air volumes within the observed time range". Compared with a closed channel, due to the high dissipation of wind force and volume under open conditions such as atmospheric airspace, it is impossible to obtain a completely accurate quantitative value in an open airspace and time domain, and even if the precise value of the air volume is obtained, it is impossible to maintain it for a long time. Obtaining a semi-quantitative value of air volume is not only simple and easy to calculate, but also has certain engineering value, so it is of great significance to quickly estimate the semi-quantitative value of air volume. Summary of the invention

[0008] In view of this, the present invention aims to provide a rotorcraft UAV for semi-quantitative real-time monitoring of wind force and volume in a certain airspace at medium and low altitudes under normal operating wind conditions, and to provide more accurate instantaneous wind force and volume monitoring data for special operations in nearby airspace.

[0009] In order to solve the above technical problems, the semi-quantitative real-time monitoring drone of low-altitude wind force and volume provided by the present invention comprises: a rotor drone and a remote controller, and a hanging swing belt.

[0010] The drone is remotely controlled by an operator, and its monitoring status can be seen by nearby workers including the operator.

[0011] A hanging ring is arranged near the center of the belly of the rotary wing UAV for hanging a hanging pendulum belt; the belly is not provided with a downward optical flow positioning module but is replaced by an optical flow positioning module on the top of the machine, or the optical flow positioning function of the belly is replaced by manual remote control by an operator.

[0012] The top of the hanging swing belt is equipped with a buckle, which can be buckled with the hanging ring on the belly of the drone to form a ring chain connection; the hanging swing belt is a variable density strip, the density of which decreases from top to bottom, and the overall density is small and the total weight is light; the hanging swing belt has a wide range, so it is easy to be blown by the wind.

[0013] Furthermore, the length of the higher-density section in the upper part of the hanging swing belt should match the length of the airflow field under the blades when the rotor UAV is flying in the air, so as to prevent it from falling into the vortex area and being entangled in the rotor when swinging in the wind; the middle and lower sections of the hanging swing belt should be set as longer medium-low density areas and lower density areas. The richer the density changes and the longer the sizes of each section, the more obvious the changes when affected by the wind, and the higher the accuracy of wind force monitoring.

[0014] The wind force and wind volume measured by the semi-quantitative real-time monitoring drone of wind force and wind volume are both vectors. In the case of no wind, the hanging pendulum belt hangs naturally and is located between the inverted cone-shaped divergent airflow fields under each rotor. When there is an external wind with a constant wind direction, and the wind direction is exactly parallel to the center line connecting the adjacent rotors of the four-rotor drone (usually the fuselage axis), this is aligned wind, and the hanging pendulum belt swings along the wind direction of the external wind and falls into the extremely weak zone of the original drone's own airflow field strength. At this time, the hanging pendulum belt has a great indication effect on the external wind.

[0015] When the field strength of the airflow generated by the UAV itself at a sufficiently long distance downward has an effect on the section of the vertical pendulum belt at that location that is weaker than the effect of the external wind field on the section of the vertical pendulum belt at that location, the section of the vertical pendulum belt at that location will swing in a directional manner under the action of the superposition of the two airflow fields, and the swinging direction will be consistent with the direction of the external wind field. Moreover, the greater the external wind force is relative to the airflow generated by the UAV itself, the closer the superposition direction of the two airflow fields is to the horizontal direction, and the greater the swinging angle of the vertical pendulum belt is. At this time, it responds to different wind forces to different degrees, because the density of the lower sections of the vertical pendulum belt is very small (the last section has the smallest density) and the inertia is also very small; when the vertical pendulum belt is blown up by the wind in the direction of the main axis or horizontal axis of the fuselage, and the upper section is pulled by the horizontal force component, the upper section close to the fuselage When the pendulum belt is swinging, the influence of the airflow field strength generated by the UAV itself is also extremely weak; therefore, the longer the swinging section of the hanging pendulum belt from bottom to top is, the greater the density corresponding to the blown section is, which means that the wind force is greater at that moment; under the blowing of effective wind force, the effect of turbulent interference relative to laminar flow on the hanging pendulum belt is manifested as a small shake and the shake amplitude of different sections is different. When reading the status, the section whose swing error meets the identification requirements can be selected to judge the wind force value; in advance, the swing angle of the section representing the wind speed of the hanging pendulum belt with obvious swinging characteristics when blown by the wind is selected as the calibration value, and the swing angle of the corresponding section can be observed during on-site wind measurement to obtain a semi-quantitative measurement value of the wind force, so the UAV can reflect the wind force value in approximate real time, and achieve real-time monitoring of the wind.

[0016] In order to enable the UAV to clearly distinguish and display different external wind forces within the measured wind force range, the hanging pendulum belt is required to show obviously different corresponding swing conditions as much as possible when different external wind forces act. This means that the density distribution and size distribution of the hanging pendulum belt are required to match the synthetic airflow field strength distribution of the airflow generated by the UAV itself under different wind forces within the measured wind force range as much as possible.

[0017] When the monitoring UAV drifts due to side wind, in addition to actively correcting the drift through remote control by the operator, the monitoring UAV can also eliminate interference and directly read and judge by utilizing the different mechanical inertia time constants between the rigid fuselage connected up and down by the ring chain and the hanging pendulum belt.

[0018] When encountering a non-changing wind and the wind direction is not parallel to the line connecting the centers of adjacent rotors of the quad-rotor UAV, it is a non-aligned wind. The lower section (especially the end section) of the hanging pendulum belt can be observed to tumble in the downwind area of ​​the rotor. At this time, the UAV should be controlled to rotate horizontally so that the line connecting the centers of adjacent rotors of the UAV (usually the axis of the fuselage) is parallel to the wind direction; when encountering a changing wind and the wind direction changes slowly, the UAV should be continuously controlled to rotate so that the line connecting the centers of adjacent rotors of the UAV (usually the axis of the fuselage) is parallel to the wind direction, and the wind direction information and wind force information should be reported in time.

[0019] When the observer estimates and records the wind volume, it should include: [the time when the wind starts, wind direction, frontal wind force (estimated and may be time-varying values), the time when the wind field airflow ends, and the wind field airflow volume (estimated and time-varying values)]. Theoretically, when the wind direction remains unchanged, the algebraic sum of the wind force during the observed period is calculated to obtain the wind volume flowing through the location of the drone during the period; the relevant operating personnel and the dispatch center in the nearby airspace should also estimate the real-time wind volume of the target coordinates (including the time when the target is affected by the wind) after receiving the [the time when the wind starts, wind direction, frontal wind force (estimated and may be time-varying values)] reported by the observer and before receiving [the time when the wind field airflow ends, and the wind field airflow volume (estimated and time-varying values)]: When encountering a time-varying wind direction, each time the wind direction changes, a new monitoring report should be started from the moment of change as the dividing point.

[0020] Furthermore, an LED series circuit can be embedded on the hanging pendulum belt and powered by a UAV power supply, so as to provide operation indications at night or in foggy and hazy weather with low visibility, thereby expanding the scope of use in different meteorological conditions; the color spectrum of the embedded LED can change according to the density of each section of the hanging pendulum belt, thereby achieving a clearer indication effect.

[0021] Furthermore, a plurality of the monitoring drones are released at the same time and are made to hover in an array in a certain airspace. The simultaneous swinging state of the hanging pendulum belts of each drone displays the distribution of wind field strength in the airspace. The weighted sum of the display result areas of the windward units can be taken to obtain the wind volume flowing through the windward surface at that moment.

[0022] When encountering a time-varying wind with a fast changing speed, it is a tornado. The drone should be controlled to move away from the wind field and report it. If necessary, the drone should be retracted. When a tornado occurs, it is only necessary to report the existence of the tornado. The drone does not measure the wind force and volume of the tornado.

[0023] The maximum value of the wind force monitored by the monitoring drone mainly depends on the wind resistance of the drone itself, and the wind resistance of different models of drones is different.

[0024] When the UAV receives a landing command or starts to land automatically due to low battery, the lower low-density section of the hanging swing belt touches the ground first, and the upper high-density section touches the ground later, until the entire machine lands and triggers the main shaft motor control circuit to cut off power; after the UAV is recovered, the buckle connection between the hanging swing belt and the UAV can be removed and folded for storage.

[0025] The beneficial effects of the present invention are: A. Low manufacturing cost and high response sensitivity. After low-cost modification, consumer-grade drones can be used to achieve semi-quantitative and intuitive monitoring of the size and direction of instantaneous wind force and volume below level 6 strong winds in medium and low airspace on the ground. B. With the assistance of ordinary optical telescopes, semi-quantitative real-time monitoring of wind force and volume in airspace greater than 300 meters up to the restricted flight altitude can be obtained at only a small additional cost; by adding LED indicator circuits, the monitoring time and space range of this drone can be expanded and its use range under more meteorological conditions can be expanded; C. The hanging swing belt connected by buckle ring chain is easy to disassemble and assemble, and can respond accordingly when it is blown by wind from all directions on the horizontal plane; the hanging swing belt adopts variable density design to indicate the wind force vector while avoiding entanglement in the rotor, which is convenient for observers to make quick judgments and estimate the wind volume according to the observation time; after optimizing the density and size parameters of each section of the hanging swing belt, higher-precision monitoring data can be obtained; D. A multi-machine monitoring array composed of multiple monitoring drones can realize the vector field indication of wind force at multiple points in a larger airspace at a relatively low cost, and then obtain the semi-quantitative estimation value of the vector field of wind volume, providing higher-precision reference data for large-scale medium and low-altitude special operations nearby that need to consider wind force and volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a hanging pendulum belt with step-change density.

[0027] Figure 2 This is a schematic diagram of a rotorcraft UAV for monitoring wind force and volume hovering in windless conditions.

[0028] Figure 3 This is a side view schematic diagram of the airflow density distribution generated by the rotor of the rotorless UAV for monitoring wind force and volume when it is hovering in windless conditions.

[0029] Figure 4 This is a top-down schematic diagram of the airflow density distribution generated by the rotor of the rotorless UAV for monitoring wind force and volume when it is hovering in windless conditions.

[0030] Figure 5 This is a schematic diagram of a rotorcraft drone for monitoring wind force and volume hovering in the wind with low wind force.

[0031] Figure 6 This is a schematic diagram of a rotorcraft UAV for monitoring wind force and volume hovering in the wind with strong wind conditions.

[0032] Figure 7 This is a side view schematic diagram of the airflow density distribution of the rotor UAV for monitoring wind force and volume when it is hovering under the condition of aligned wind from the side and the hanging pendulum belt swings under the combined action of the airflow generated by its own rotor and the external wind.

[0033] Figure 8 This is a front view schematic diagram of the airflow density distribution of the rotor UAV for monitoring wind force and volume when it is hovering under the condition of aligned wind from the side and the hanging pendulum belt swinging under the combined action of the airflow generated by its own rotor and the external wind.

[0034] Fig. 9 This is a top-down schematic diagram of the airflow density distribution of the rotor UAV for monitoring wind force and volume, when the hanging pendulum belt swings under the combined action of the airflow generated by its own rotor and the external wind when the rotor UAV is hovering under the condition of aligned wind from the side.

[0035] Fig.10 This is a top-down schematic diagram of a rotor UAV that monitors wind force and volume while hovering in non-aligned wind conditions, with the hanging pendulum belt swinging under the combined action of the airflow generated by its own rotor and the external wind.

[0036] Fig.11 Schematic diagram of the wind force and wind volume relationship estimation used by the rotorcraft UAV for monitoring wind force and wind volume.

[0037] Fig.12 Schematic diagram of the estimated wind exposure time at the target served by the rotorcraft UAV for monitoring wind force and volume.

[0038] Figure 1 —— Fig.10 Among them, 1 is buckle, 2 is section A of vertical hanging pendulum belt, 3 is section B of vertical hanging pendulum belt, 4 is section C of vertical hanging pendulum belt, 5 is section D of vertical hanging pendulum belt, 6 is section chain of vertical hanging pendulum belt, 7 is rotor UAV, 8 is rotor, 9 is ring, 10 is area of ​​high flux density of airflow generated by the rotor of UAV itself, 11 is area of ​​low flux density of airflow generated by the rotor of UAV itself, 12 is area of ​​overlapping of area of ​​low flux density of airflow generated by adjacent rotors; and in each section of vertical hanging pendulum belt: density of section A > density of section B > density of section C > density of section D. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below in conjunction with specific implementations verified by field experiments and accompanying drawings. Obviously, the described implementations are only part of the implementations of the present invention, rather than all of the implementations.

[0040] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9 , Fig.10 , Fig.11 and Fig.12 , Figure 1 The present embodiment adopts a hanging pendulum belt with a step-change density form, wherein the density of the hanging pendulum belt section A 2 is greater than the density of the hanging pendulum belt section B 3, which is greater than the density of the hanging pendulum belt section C 4, which is greater than the density of the hanging pendulum belt section D 5, and the total weight of the hanging pendulum belt does not exceed the maximum load of the rotor UAV 7; Figure 2 , Figure 5 ,and Figure 6 Schematic diagrams of the rotor UAV for monitoring wind force and volume when hovering under no wind conditions, under wind-aligned and low wind conditions, and under high wind conditions; Figure 3 , Figure 4 They are respectively a side view schematic diagram and a top view schematic diagram of the airflow density distribution generated by the rotor of the rotor UAV for monitoring wind force and wind volume when it is hovering in windless conditions; Figure 7 , Figure 8 , Fig. 9 They are respectively a side view schematic diagram, a front view schematic diagram, and a top view schematic diagram of the rotor UAV for monitoring wind force and volume when it is hovering under the condition of aligned wind from the side, when the hanging swing belt swings under the combined action of the airflow generated by its own rotor and the external wind; Fig.10 This is a top-down schematic diagram of the rotor UAV for monitoring wind force and volume when the hanging swing belt swings under the combined action of the airflow generated by its own rotor and the external wind when it is hovering under non-aligned wind conditions; Figure 1 —— Fig.10 Among them, 1 is a buckle, 2 is a vertical hanging pendulum belt section A, 3 is a vertical hanging pendulum belt section B, 4 is a vertical hanging pendulum belt section C, 5 is a vertical hanging pendulum belt section D, 6 is a vertical hanging pendulum belt section chain, 7 is a rotor UAV, 8 is a rotor, 9 is a hanging ring, 10 is an area of ​​high flux density of airflow generated by the UAV's own rotor, 11 is an area of ​​low flux density of airflow generated by the UAV's own rotor, 12 is an overlapping area of ​​low flux density of airflow generated by adjacent rotors. Fig.11 Schematic diagram of wind force and wind volume relationship estimation used by the rotorcraft UAV for monitoring wind force and wind volume; Fig.12Schematic diagram of the estimated wind exposure time at the target served by the rotorcraft UAV for monitoring wind force and volume.

[0041] In this specific embodiment, the present invention first sets a hanging ring 9 on the belly of a quad-rotor drone, and prepares a 4-section hanging swing belt. The sections of the hanging swing belt are arranged in sequence according to density and are pre-connected with a lightweight hanging swing belt section chain 6, and a lightweight buckle 1 is installed at the top with the highest density. The size of the buckle 1 matches the size of the hanging ring 9 to form a loose chain connection so that the buckle 1 can still swing freely after the hanging swing belt is buckled to the hanging ring 9 on the belly of the rotor drone 7; the selected quad-rotor drone is a customized drone without optical flow positioning on the belly.

[0042] In this specific implementation, after canceling the optical flow positioning of the drone's belly downward, satellite positioning can be used during use, or the drone can be manually remotely controlled when there is no satellite signal to achieve stable hovering of the drone.

[0043] In one embodiment, the UAV 7 used in the experiment has a wingspan of 30×30 cm, a height of 8.7 cm, a mass of 223 grams without a hanging pendulum belt, and a maximum wind resistance of level 5.

[0044] In this specific implementation, the length, weight, width, and density distribution of each section of the hanging pendulum belt are determined according to the rule that the density is large at the top and small at the bottom, and the mass is heavy at the top and light at the bottom. When determining the value of this parameter group, factors such as the power and size parameters of the rotor UAV 7, the wind force range to be monitored, and the ambient air pressure need to be considered; after multiple calculations and repeated experimental verifications, a set of parameter value combinations are obtained. Each section of the hanging pendulum belt is 4 cm wide and 30 cm long. The mass of each section of the hanging pendulum belt is as follows (in grams): Section Section A 2 Section B 3 Section C 4 Section 5 Ring quality 10.20 7.83 4.64 2.90 Ring removal quality 9.87 7.50 4.31 2.57 After installing the pendulum belt, the rotor drone for monitoring wind force and wind volume has a total weight of 249 grams, and the wind measurement range is between 0 and 4. The wind force and wind speed table is as follows: series 0 1 2 3 4 name No wind light air Light Breeze Light or warm breeze Japanese style Wind speed (m / s) 0~0.2 0.3~1.5 1.6~3.3 3.4~5.4 5.5~7.9

[0045] In this specific implementation, before the drone is released, the hanging swing belt is buckled onto the belly of the rotor drone 7 and laid flat on the ground before taking off. The flight altitude must not be lower than the total length of the hanging swing belt after it is extended. After flying to the designated altitude of the airspace where wind measurement is required, the drone is kept in a hovering state. At this time, the operator of the remote control drone controls the drone to hover and turn stably while observing the state of the hanging swing belt, and reports the observation results to nearby operators while estimating the size and direction of wind force and volume. Wind measurement can be observed with the naked eye at a true height of about 0 to 50 meters, and a higher distance beyond visual resolution requires observation with the help of a telescope.

[0046] In this embodiment, the force analysis is performed on the lowest section (section D 5) and other sections of the hanging swing belt. The lowest section D 5 of the hanging swing belt has the smallest density and the lightest mass. When it is blown by the inclined airflow field in any vertical plane, it is most likely to swing in the direction of the flow field, and also generates a pulling force in this direction on the lower hanging part of the upper section. At this time, the force on section D 5 includes gravity, airflow blowing force, and pulling force of the upper section; the other sections of the hanging swing belt will also swing in the direction of the airflow field under the action of their own gravity, the pulling force of the lower section, the upper pulling force, and the blowing force of the airflow at the position of each section, but because the upper sections have a higher density and a greater gravity, and the higher the section, the smaller the inclination of the synthetic airflow at the corresponding height, so the swing amplitude is also smaller.

[0047] In this embodiment, when the UAV is hovering in a windless environment, the lower hanging swing belt is only in the low flux density area 11 of the airflow generated by the UAV's own rotor and the overlapping area 12 of the low flux density area of ​​the airflow generated by the adjacent rotor. Figure 3 , Figure 4 As shown in the figure, the hanging swing belt shakes slightly under the downward airflow of the UAV's own rotor and rotates freely around the vertical axis under the constraint of the hanging swing belt segment chain 6, which can provide a larger windward angle when the wind blows from any direction, so as to respond in time. When the UAV encounters aligned wind (positive or sideways) when hovering, the lower hanging swing belt swings or maintains a tilted state in the vertical plane of the wind direction and the hanging ring 9, and the swinging direction of each segment is consistent when swinging. Figure 7 , Figure 8 , Fig. 9 As shown. When the UAV encounters non-uniform wind while hovering, the lower hanging swing belt will blow into the low-flux density area 11 of the airflow generated by the rotor of the UAV on the downwind side and approach or even blow into the high-flux density area 10 of the airflow generated by the rotor of the UAV on the downwind side; at this time, in addition to its own gravity, the tension of the hanging swing belt segment chain 6, and the blowing of the non-aligned wind direction, the force on the lower section of the hanging swing belt is also affected by the asymmetric force of the airflow generated by the rotor of the UAV itself - the asymmetric force of the high-flux density area 10 blowing toward the low-flux density area 11, so that the hanging swing belt, under the constraint of the hanging swing belt segment chain 6, swings vertically along the asymmetric wind direction and swings horizontally left and right at the edge of the high-flux density area 10 of the airflow below the rotor of the UAV on the downwind side. Fig.10 As shown; the swings in these two directions become a spiral dance along the asymmetric wind direction after Lissajous synthesis. At this time, when the operator below observes the hanging pendulum belt, he may see both up and down tumbling and inconsistent swing directions of each section.

[0048] Furthermore, when the wind direction is approximately parallel or vertical to the connecting line of the centers of the adjacent rotors of the quad-rotor drone, the lower section of the hanging pendulum belt does not enter the high-flux density area 10 of the airflow generated by the drone's own rotor to a small extent, and the asymmetric force on the airflow generated by the drone's own rotor is small. At this time, the degree of spiral dancing of the hanging pendulum belt is very weak; if the operator stands directly below the drone 7 and looks up vertically, the tilt direction of the asymmetric wind can be directly determined by the horizontal swing direction, or the tilt direction of the asymmetric wind can be determined according to which side the center of the spiral dancing trajectory circle of the hanging pendulum belt deviates, so as to adjust the drone 7 to the aligned wind direction; if the operator stands obliquely below the drone 7 at this time, he can move a few steps to the left and right facing the drone 7, observe the deflection of the non-aligned wind direction from different angles, and then adjust the direction of the drone 7 to the aligned wind direction. The deflection angle can also be ignored for non-aligned wind directions within the error allowable range and read directly.

[0049] In this embodiment, when the drone is adjusted to align with the wind direction and semi-quantitatively observes the wind force value, it is necessary to use both sampling and retrieval elements to complete the measurement, namely: sampling the effective swing angle of the effective swing section of the hanging pendulum belt and retrieving the calibrated swing angle-wind force value table of each section. When the aligned wind is a constant continuous wind, each section of the hanging pendulum belt maintains a certain angle of tilted blowing state or has a slight fluctuation near the tilted blowing position. At this time, the tilt angle of each section below is the effective swing angle of the section; refer to the aforementioned wind force and anemometer, with 30 degrees, 45 degrees, and 60 degrees as the main identification boundary angles, use artificial wind and anemometer to calibrate and measure each effective section of the hanging pendulum belt at each wind speed: (Experimental air pressure 100.5kPa, temperature 27 degrees Celsius, humidity 76%) The swing angle-wind force value data table that can be referenced after a calibration is as follows: Wind level Section B Section C Section D Level 1 soft wind -- -- About 30 degrees Level 2 light wind -- About 30 degrees 45 to 60 degrees Level 3 breeze or warm wind -- About 45 degrees About 60 degrees Level 4 Zephyr Less than 45 degrees About 60 degrees Close to 90 degrees horizontal When measuring wind in practice, we often encounter unstable wind conditions with fluctuating wind speeds. Fig.11As shown in the figure, the response sensitivity of the hanging pendulum belt is sufficient under the aligned wind conditions, so the effective sections of the hanging pendulum belt will swing up and down with the fluctuation of wind force. In this case, it is necessary to first determine the wind measurement period according to the swing amplitude range of the effective section - the average swing amplitude of the effective section in the same wind measurement period remains unchanged, and this average swing amplitude is the effective swing angle in the period, and the corresponding wind level can be retrieved from the calibrated swing angle-wind force value table with this effective swing angle; when the average swing amplitude changes significantly, it means that the wind force value has changed, and a new wind measurement period needs to be opened and the new average swing amplitude needs to be observed in the new wind measurement period That is, the new effective swing angle, so the same method is used to retrieve the new wind level; the minimum swing period for sampling the effective swing angle of the hanging pendulum belt is generally 3 to 5 up and down swings. When the wind value changes rapidly, the observation accuracy can be relaxed and the maximum swing amplitude and the frequency of occurrence of the maximum swing amplitude can be observed, and the same wind measurement period can be extended to obtain wind values ​​with lower accuracy based on the observer's calculation and recording capabilities; the pressure gradient does not change much in general working weather. If the wind value changes greatly, rapidly and frequently, it is likely to face drastic weather changes. At this time, it is necessary to warn the surrounding workers and retrieve the equipment in time. Every time the wind measurement period is updated, the observer must report and record the wind change time and the new wind value at the start and end times.

[0050] Furthermore, if the atmospheric environment at the actual wind measurement site is very different from the atmospheric conditions during the above-mentioned experimental wind measurement, a secondary calibration must be performed at the wind measurement site in advance; during the secondary calibration, the on-site wind speed can be first measured near the ground and then compared with the swing angle-wind force value table of the above-mentioned primary calibration. If the difference between the two is within the semi-quantitative measurement error range, the secondary calibration link can be skipped and the wind measurement work can be carried out directly. If the difference between the two is too large, a complete secondary calibration must be carried out first and the local swing angle-wind force value table must be updated before the wind measurement work can be carried out; the auxiliary tools required for the secondary calibration include an anemometer and an artificial wind source, and then a nearby shelter can be found or carried out during a windless period.

[0051] In this specific implementation, before launching the drone, the high-frequency wind direction of the wind rose diagram of the place on that day is pre-judged based on the weather forecast wind direction and the perceived wind direction near the observation point. After the drone is launched and hovered according to the high-frequency wind direction as the preset aligned wind direction, the direction of the drone is adjusted to the aligned wind direction in combination with the actual wind direction and the actual wind direction is recorded. When adjusting the drone to the aligned wind direction, the direction of the drone can be turned (small fine-tuning) each time, and then a few seconds are waited to see the swing recovery of the hanging pendulum belt, and this is repeated until it recovers to the "aligned wind" angle. The start and end times of adjusting the drone to the aligned wind direction are the end time of the previous wind measurement period and the start time of the next wind measurement period, respectively. The time used to adjust the drone from the non-aligned wind direction to the aligned wind direction affects the overall wind measurement accuracy, and the operation requires strong skill.

[0052] In this specific implementation, the complete information of wind speed and volume that the observer semi-quantitatively observes, records and broadcasts should include: [the time when the wind starts or the start time of the wind measurement period, wind direction, frontal wind speed (estimated and may be time-varying value) or semi-quantitatively observed average wind speed, the end time of the wind measurement period, and estimated wind volume (estimated and time-varying value)] such as Fig.11 As shown in the figure, when the wind is aligned with a constant wind direction and only the wind force changes, in this 5-dimensional vector, only the 1st, 3rd, 4th, and 5th dimensional components need to be updated when the wind force changes. Theoretically, when the wind direction remains unchanged, the instantaneous value of the wind volume flowing through the position of the drone during the period can be obtained by integrating the magnitude of the variable wind force during the observation period; the wind volume can be estimated by the observer, the operator who reports the received wind data, and the dispatch center, or by a computer (including an intelligent device with a dedicated processor); when the observer actually estimates, the approximate average value of the wind force during the observation period can be multiplied by the wind measurement duration, and then the algebraic sum is calculated with the wind volume value of the previous observation period to obtain the approximate cumulative value of the wind volume flowing through the position of the drone at that moment. When encountering time-varying wind direction, each change in wind direction should be recalculated, recorded and reported at the same time; after receiving the [wind start time, wind direction, frontal wind force (estimated and may be time-varying value)] reported by the observer and before receiving the [wind field airflow end time, wind field airflow volume (estimated and time-varying value)], the relevant operating personnel and dispatch center in the nearby airspace should also estimate and judge the wind impact time at the target coordinates and the real-time wind volume that the target will receive. Fig.12 As shown, the time when the target coordinate is affected by wind = the time when the wind starts at the wind measuring point + (the distance between the target coordinate and the wind measuring point coordinate) / (frontal wind force × wind direction to the cosine value of the angle between the two points).

[0053] Furthermore, the semi-quantitative real-time monitoring drone of wind force and volume can obtain greater wind measurement capability after replacing a larger power and higher efficiency brushless motor and increasing the battery capacity. The number of sections of the hanging pendulum belt loaded thereon can also be divided into other numbers. When the number of sections tends to be extremely large and the length of each section tends to be extremely small, it becomes a hanging pendulum belt in the form of a continuously changing density. The width, shape, and thickness of each section of the pendulum belt can also be changed accordingly according to actual needs and flight control power limitations. The hanging pendulum belt can also be embedded with LED circuits for use at night or in foggy weather with low visibility. Each time the drone body or the hanging pendulum belt is changed, the swing angle-wind force value table should be recalibrated under the new parameter conditions.

[0054] For multi-machine monitoring array situations, the three-dimensional position coordinates should be pre-numbered when in use, and the distance between each flying machine should be more than twice the total length of the hanging pendulum belt. When measuring the monitoring results, the coordinate value of each machine during measurement should be added after the wind speed and volume data. When the wind speed data is large, it is advisable for multiple people to jointly control, with each person controlling and monitoring a UAV at each coordinate.

[0055] In this specific implementation, when the monitoring task is completed or the drone is low on power, it should be recovered in time. When recovered, the monitoring drone will land vertically and land in the order of the vertical pendulum belt D section 5, the vertical pendulum belt C section 4, the vertical pendulum belt B section 3, the vertical pendulum belt A section 2, and the rotor drone 7 fuselage. When the rotor drone 7 feet touch the ground first or the vertical pendulum belt sections fold to cover the belly of the rotor drone 7 and cannot descend, the drone rotor main shaft motor drive circuit is powered off, thereby completing the recovery of the monitoring drone. In addition, if the entire section of the vertical pendulum belt is pulled by excessive wind and tends to be horizontal, the uppermost section A section 2 is tilted, the last section D section 5 also swings up and down with the horizontal plane as the center line, and the rotor drone 7 has an inclination angle close to 45 degrees, it is close to the monitoring limit and should be recovered immediately and an alarm should be given.

[0056] The above is a detailed introduction to the semi-quantitative real-time monitoring drone of medium and low altitude wind force and volume provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians who use the present invention in this technical field and other fields, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. Semi-quantitative real-time monitoring drone of medium and low altitude wind force and volume, including: Rotary-wing UAV, remote control and hanging pendulum belt.

2. The semi-quantitative real-time monitoring drone for medium and low altitude wind force and volume as claimed in claim 1 is characterized by: The pendulum belt is suspended below the drone, and when the drone is hovering, it can swing in different directions in real time according to the instantaneous wind blowing in different directions.

3. The semi-quantitative real-time monitoring drone for medium and low altitude wind force and volume as claimed in claim 2 is characterized by: The density of each section of the hanging pendulum belt is distributed in a pattern of larger density at the top and smaller density at the bottom, and the total length of the sections of the hanging pendulum belt connected in series exceeds the high flux density area of ​​the UAV rotor airflow, thereby ensuring that the lower section of the hanging pendulum belt can respond to the measured external wind force and will not be drawn into the rotor blades due to turbulent interference.

4. The semi-quantitative real-time monitoring drone for medium and low altitude wind force and volume as claimed in claim 1 is characterized by: By calibrating the wind-induced swing angles of the hanging pendulum belt sections and then retrieving and comparing the swing angles of the corresponding sections during on-site wind measurements, a semi-quantitative estimation of wind force can be achieved.

5. The semi-quantitative real-time monitoring drone for low-altitude wind force and volume as claimed in claim 1, characterized in that: the rotor The number of rotors of the UAV is even, and when the monitored wind direction is inclined to the line connecting the midpoints of adjacent rotors, the operator remotely controls the UAV to turn so that the line connecting the midpoints of adjacent rotors of the UAV is parallel or perpendicular to the wind direction, thereby achieving the best response effect of the hanging swing belt during monitoring and determining the start and end times of the winds of different monitored wind directions, and then estimating the semi-quantitative value of the atmospheric wind volume during the measuring period at the observation point through real-time monitoring and recording of the instantaneous wind force and the duration of different wind forces and different wind directions.

6. The semi-quantitative real-time monitoring drone for medium and low altitude wind force and volume as claimed in claim 1, characterized in that: The pendant strap can be folded up or deployed depending on whether the drone is in use or not.

7. The semi-quantitative real-time monitoring drone for medium and low altitude wind force and volume as claimed in claim 1 is characterized by: Its monitoring range can be improved after LED upgrade.

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