CN110220666A - Wind field detection device and the detection of online wind field and evaluation method based on microstrain - Google Patents

Abstract

The invention belongs to plant protection to be sprayed field, be related to a kind of wind field detection device based on microstrain and the detection of online wind field and evaluation method, and the stabilization wind field for being mainly used for the generations such as unmanned plane under floating state, wind tunnel test, air curtain carries out on-line checking.The present invention presses curved process using polypropylene foil come the blade wind-engaging under modeling wind field, is attached at the change in resistance that the foil gauge of polypropylene foil is bent and occurs therewith, measures wind speed and direction according to pressure difference signal in the full-bridge circuit of foil gauge composition.Automatic adjustment detection height can be achieved in the present invention, it can be achieved simultaneously to be used for quickly detecting multiple spot X, Y, Z-direction wind speed in same level face, and calculate the wind direction and air speed value, it can be achieved that test point position accurate adjusting, the distributing homogeneity of wind field can also be evaluated.Wind field detection device detection sensitivity of the invention is high, and detection accuracy is high, and service life with higher, detection part is low in cost and is easily changed.

Description

Micro-strain based wind field detection device and online wind field detection and evaluation method

technical field

The invention relates to a micro-strain-based wind field detection device and an online wind field detection and evaluation method, belonging to the field of plant protection spraying.

Background technique

In the field of agricultural plant protection, the spraying application of plant protection drones in the field continues to advance, and the orchard wind-assisted spraying machine gradually replaces the traditional shower spraying machine, and the wind field generated by the machine helps the mist to penetrate the dense canopy It also promotes the turning of the leaves, improves the attachment rate of the leaves, and has an important impact on the drift, uniformity and coverage of the droplets. Testing is also very important. Chinese invention patent application (application number: 201710439738.1) discloses a fan hidden wind speed detector, the device uses a fan wheel to detect wind speed, and the fan can be hidden in the inner cavity of the controller shell when not in use; Chinese invention patent application (application number : 201810467180.2) discloses a test system and method for a three-dimensional wind field of a rotor UAV, and proposes a test method for a three-dimensional wind field of a rotor UAV based on a combination of a wireless wind speed sensor and a spatial grid, and quickly measures each space grid test point wind speed. The above-mentioned wind speed measurement devices are mainly wheel-type and heat-sensitive anemometers. The wheel-type anemometers require high precision and are expensive. The wind wheel is easily damaged and difficult to replace, and has poor perception of wind speed changes; The platinum wire of the probe is easily damaged and is easily affected by turbulence in the downwash airflow of the drone, making the measured value higher than the real value. It is difficult to accurately locate, and only a single point can be measured at a time. It is difficult to meet the needs of simultaneous detection of multiple sets of data in different positions in the laboratory. The collection efficiency is low, and precise positioning measurement and remote control cannot be realized.

Contents of the invention

In view of the above technical problems, an object of the present invention is to provide a wind speed measurement system with high detection sensitivity, high detection accuracy, long service life, low cost and easy replacement of detection components, high degree of automation, high efficiency and rapidity, and multi-point measurement. The wind field detection device based on micro-strain, uses polypropylene sheet to simulate the blade under the wind field, and uses the resistance value change of the strain sheet to be bent by the wind to convert it into a differential pressure signal to detect the wind speed, which can realize the detection of the drone in the hovering state , wind tunnel test, wind curtain machine and other stable wind field for online detection, according to the purpose of the experiment, the wind speed of any target direction can be detected, and the wind speed and direction of the point can be calculated according to the measured wind speed values in X, Y, and Z directions. A large amount of wind field data is collected and transmitted to the computer in real time, and the distribution uniformity of the wind field can also be evaluated.

Another object of the present invention is to provide an online wind field detection method and an online wind field distribution uniformity evaluation method.

In order to achieve the above object, the present invention provides the following technical solutions:

When wind fields of different intensities act on the polypropylene sheet of the same size, different degrees of bending deformation will occur, and the four strain gauges attached to the polypropylene sheet will undergo the same bending deformation, which will cause the resistance value of each strain gauge to change, and the output The voltage difference changes accordingly, and the output voltage difference is positively correlated with the wind speed.

The wind field detection device of the present invention detects the wind field during plant protection spraying according to the change of the output voltage difference caused by the change of the resistance value of the strain gauge, and can adjust the measured wind direction and the height of the measured horizontal plane in real time.

A wind field detection device based on micro-strain, the device includes a support bar rotation mechanism, a horizontal rotation mechanism, an wind measurement distance adjustment mechanism, an automatic height adjustment mechanism and a control mechanism.

Wherein, the horizontal rotating mechanism includes a rotating frame 1, a rotating disk 12, a first stepping motor 13 and a first angle sensor 18; Square shelf and lower square shelf.

The lower end surface of the rotating disk 12 is fixed on the output shaft of the first stepper motor 13, and the edge of the rotating disk 12 is affixed to the lower square frame of the rotating frame 1 through a plurality of supporting spokes 8; the first angle Two parts of the sensor 18 are respectively fixed on the lower end faces of the first stepper motor 13 and the rotating disc 12 .

The supporting bar rotation mechanism includes a supporting bar 4, a fixed base 5, a moving base 6, a rotating bearing 7, a second angle sensor 30, a rotating driven gear 31, a driving gear 32, a rotating outer wheel 33 and a second stepping motor 34: Two opposite beams in the upper square frame of the rotating frame 1 are provided with base moving slots 19 along the length direction of the beams.

A pair of fixed bases 5 are respectively fixed in the middle part of the base moving grooves 19 of the two crossbeams, and the even-numbered pairs of moving bases 6 can be horizontally moved in the base moving grooves 19, and the even-numbered pairs of moving bases 6 are arranged in two The connection lines between the fixed bases 5 are distributed symmetrically.

Each fixed base 5 and each mobile base 6 are provided with rotating bearings 7; between the rotating bearings 7 of two corresponding fixed bases 5, and the rotation of every two corresponding mobile bases 6 A support bar 4 is fixedly connected between the bearings 7; a plurality of polypropylene sheets 2 and a plurality of voltage amplifiers 3 corresponding to the polypropylene sheets 2 are arranged on each support bar 4, and a plurality of voltage amplifiers 3 on each support bar 4 The polypropylene sheet 2 is distributed in an n×n equidistant array in the plane; the surface of the polypropylene sheet 2 is provided with multiple pairs of parallel strain gauges 41 arranged alternately in front and back, and each strain gauge 41 is connected by a differential full bridge The connection mode is connected with the voltage amplifier 3.

The outside of each fixed base 5 is provided with a rotating driven gear 31 connected with the rotating bearing 7 in the fixed base 5, and the outer side of each moving base 6 is provided with a rotating bearing connected with the rotating bearing 7 in the moving base 6. 7 connected rotating outer wheels 33; a rotating driven gear 31 on the same side and a plurality of rotating outer wheels 33 are connected by a length-adjustable rotating connecting rod; the driving gear 32 is meshed with the rotating driven gear 31, The driving gear 32 is connected with the output shaft of the second stepper motor 34 fixed on the beam of the upper square frame of the rotating frame 1; the two parts of the second angle sensor 30 are respectively fixed on the fixed base 5 and the rotating driven on gear 31.

The wind measuring distance adjustment mechanism is fixedly connected between the fixed base 5 and the mobile base 6 .

Described automatic height adjustment mechanism comprises multistage hydraulic lift cylinder 14, displacement sensor 15 and base 16; Described multistage hydraulic lift cylinder 14 is vertically installed on the base 16, and the piston rod end of multistage hydraulic lift cylinder 14 is connected with the The bottom end of the stepping motor 13 is affixed; the displacement sensor 15 is fixed on the bottom end of the first stepping motor 13 .

The control mechanism includes a power supply 9 arranged on a rotating disk 12 , a data acquisition card 10 , a wireless transmission module 11 and a control module 17 .

Each voltage amplifier 3 is connected to a data acquisition card 10; the data acquisition card 10 can simultaneously collect multiple sets of voltage data, and transmit them to a remote computer through a wireless transmission module 11 to record and draw a wind field map.

The power supply 9 is each voltage amplifier 3, data acquisition card 10, wireless transmission module 11, first stepper motor 13, multi-stage hydraulic lifting cylinder 14, displacement sensor 15, control module 17, first angle sensor 18, The second angle sensor 30 and the second stepping motor 34 are powered.

The control module 17 controls the multi-stage hydraulic lifting cylinder 14, the first stepping motor 13 and the second stepping motor 34, receives the monitoring data of the displacement sensor 15, the first angle sensor 18 and the second angle sensor 30, and transmits the data via wireless The transmission module 11 communicates with the remote computer.

The support bar rotation mechanism includes two pairs of moving bases 6, and the rotating connecting rod includes a rotating inner sleeve rod 24 and two rotating outer sleeve rods 25 respectively sleeved at two ends of the rotating inner sleeve rod 24, and the rotating inner sleeve rod 24 Between the rotating outer sleeve rod 25, the clamping and positioning are carried out by the hexagon socket bolt 26, the hexagon nut 27 and the front and rear two spacers 28, wherein the rotating inner sleeve rod 24 is riveted on the rotating driven gear 31, and the two rotating outer sleeve rods 25 Respectively riveted on the two rotating outer wheels 33; the wind measuring distance adjustment mechanism includes a moving inner sleeve rod 21 and a moving outer sleeve rod 22 sleeved on the outside of the moving inner sleeve rod 21, and the moving inner sleeve rod 21 can move the outer sleeve rod 22 Slide inside, and be clamped and positioned by the clamping bolt 23; The end of the moving inner sleeve rod 21 and the end of the moving outer sleeve rod 22 are fixedly connected to the fixed base 5 and the moving base 6 respectively.

The surface of the polypropylene sheet 2 is pasted with two pairs of parallel strain gauges 41 alternately arranged in front and back through the sticking film 42, which are: the first strain gauge a, the second strain gauge b, the third strain gauge c and the first strain gauge Four strain gauges d; wherein, the first strain gauge a and the third strain gauge c are pasted on the front side, and the second strain gauge b and the fourth strain gauge d are pasted on the reverse side.

An online wind field detection method utilizing the described micro-strain-based wind field detection device, comprising the steps of:

a. Establish the three-dimensional coordinate system of the wind field detection device:

Adjust the wind field detection device to the initial state, and the polypropylene sheet 2 is in a horizontal state;

Set the center point of the rotating frame 1 on the horizontal plane where the polypropylene sheet 2 is located as the origin O of the three-dimensional coordinate system, the X axis is parallel to the support bar 4, the positive direction is backward, the Y axis is perpendicular to the support bar 4, the positive direction is to the left, and the Z axis is Vertical to the XOY horizontal plane, the positive direction is downward;

b. Establish a simplified relationship model between wind speed v and output voltage difference U in different wind directions:

b1. Set the anemometer at a certain test distance from the air outlet of the speed-adjustable fan, and measure n gradually increasing wind speeds v _i (i=0,1,2,3...n), and the wind speed range is 0～ 10m/s, wherein when v ₀ =0, adjust the resistance value of the voltage amplifier 3 so that the output voltage difference U is 0, that is, U ₀ =0;

b2. Use the blower to blow out the measured winds of n wind speeds v _i step by step to the polypropylene sheet 2 in any horizontal state along the positive direction of the Z axis and the negative direction of the Z axis respectively at the said test distance, and blow them respectively to the polypropylene sheet 2 in any horizontal state The polypropylene sheet 2 in any vertical state blows out the measured n wind speeds v _i gradually increasing wind along the positive direction of the Y axis and the negative direction of the Y axis; in the process, the corresponding voltage amplifier 3 is collected by the data acquisition card 10 data, obtain the output voltage difference U _i corresponding to the wind speed v _i in different winds, and finally obtain the positive direction of the Z axis, the negative direction of the Z axis, the positive direction of the Y axis, the negative direction of the Y axis, the positive direction of the X axis and the The relationship model between the wind speed v in the negative direction of the X-axis and the output voltage difference U; among them, the relationship model between the positive direction of the X-axis and the positive direction of the Y-axis is the same, and the relationship model between the negative direction of the X-axis and the negative direction of the Y-axis is the same; the difference will be obtained Perform polynomial fitting on n different wind speed values and output voltage difference signals in the wind direction, establish a model of wind speed v and output voltage difference U, and determine the error correction coefficient k _j :

v=k _j U(j=1,2,3,4) Formula 2

In the formula, the unit of wind speed v is m/s, the unit of output voltage difference U is V, k _j is the error correction coefficient of different wind directions, k ₁ is the wind direction calibration coefficient in the positive direction of Z-axis, and k ₂ is the wind vane in the negative direction of Z-axis Fixed coefficient, k ₃ is the wind direction calibration coefficient in the positive direction of the X and Y axes, and k ₄ is the wind direction calibration coefficient in the negative direction of the X and Y axes;

c. Wind field detection:

c1. Place the wind field detection device adjusted to the initial state at the detection position of the wind field to be measured, and simultaneously record the detection coordinates of each polypropylene sheet 2 in the three-dimensional coordinate system;

c2. Record the output voltage difference U _z of the Z-axis direction of the polypropylene sheet 2 in each horizontal state corresponding to each detection coordinate, the output voltage difference U _y of the Y-axis direction of the polypropylene sheet 2 in each vertical state, and The output voltage difference U _x in the direction of the X axis; according to the positive and negative values of U _z , U _y and U _x , select the positive direction of the Z axis, the negative direction of the Z axis, the positive direction of the Y axis, and the negative direction of the Y axis obtained in step b , the relationship model between the wind speed v in the positive direction of the X axis and the negative direction of the X axis and the output voltage difference U, and obtain the wind speed v _z in the direction of the Z axis corresponding to each detection coordinate, the wind speed v _y in the direction of the Y axis, and the voltage in the direction of the X axis wind speed v _x ;

c3. Calculate and obtain the wind speed and wind direction of each detection coordinate through formula 3 and formula 4 and wind speed

In the formula, v _z is the wind speed in the Z-axis direction, v _y is the wind speed in the Y-axis direction, v _x is the wind speed in the X-axis direction, and the unit is m/s; It is a three-dimensional vector, containing wind direction and wind speed value information; v _x , v _y , v _z contain positive and negative direction information and wind speed.

The concrete process of described step b2 is as follows:

b2.1. Move the fan to the test distance directly above any horizontal polypropylene sheet 2, and blow n winds with increasing wind speed v _i step by step downward in turn. When the wind speed is v _i , the polypropylene sheet 2 Cooperate with the strain gauge 41 to bend downward and deform, the resistance value of the strain gauge 41 changes, and the output differential voltage changes, the data acquisition card 10 collects the voltage data of the voltage amplifier 3, and transmits the output corresponding to different wind speeds v _i through the wireless transmission module 11 The voltage difference U _i is transmitted to the remote computer terminal for display and recording, and the remote computer terminal obtains the polynomial fitting relationship model between the wind speed v in the positive direction of the Z axis and the output voltage difference U according to formula 2: v=k ₁ U;

b2.2. Move the fan to the test distance directly below the polypropylene sheet 2 in any horizontal state, and blow n winds with increasing wind speed v _i step by step upwards in turn. Other operations are the same as step b2.1, here When the voltage and wind speed are all negative values, the polynomial fitting relationship model between the wind speed v in the negative direction of the Z axis and the output voltage difference U is obtained: v=k ₂ U;

b2.3. Change the fan to blow air along the positive direction of the Y-axis, the test distance remains unchanged, the support bar 4 is rotated 90° clockwise, and the polypropylene sheet 2 is adjusted vertically downward and perpendicular to the Y-axis. Other operations are the same as Step b2.1 is the same, at this time, the voltage and wind speed are all positive values, and the polynomial fitting relationship model between the wind speed v in the positive direction of the Y axis and the output voltage difference U is obtained: v=k ₃ U; the positive direction of the X axis and the positive direction of the Y axis The relational model is the same;

b2.4. Change the fan to blow air along the negative direction of the Y-axis. Other operations are the same as step b2.1. Combined relationship model: v=k ₄ U; the relationship model in the negative direction of the X axis is the same as that in the negative direction of the Y axis.

The specific process of the step c2 is as follows:

1) The polypropylene sheet 2 in the horizontal state can detect the wind field velocity v _z in the Z-axis direction. The polypropylene sheet 2 corresponding to each detection coordinate cooperates with the strain gauge 41 to sense the bending deformation of the wind field, and the resistance value of the strain gauge 41 changes. When the output differential voltage changes, the data acquisition card 10 collects the voltage data of each voltage amplifier 3, and transmits the output voltage difference U _z in the Z-axis direction corresponding to each detection coordinate to the remote computer through the wireless transmission module 11, and the remote computer According to the relationship model between the wind speed v in the positive direction of the Z axis or the negative direction of the Z axis and the output voltage difference U in step b, the terminal converts U _z to v _z and records the data; where the value of U _z is positive, use the error The Z-axis positive direction relationship model with a correction factor of k ₁ calculates the wind speed, and the wind direction is along the Z-axis positive direction; when the value of U _z is negative, use the Z-axis negative direction model with an error correction factor of k ₂ to calculate the wind speed, and the wind direction is along the Z-axis negative direction;

2) In order to detect the wind speed v _y in the Y-axis direction, the support bar 4 is rotated 90° clockwise, and the polypropylene sheet 2 is adjusted vertically downward and perpendicular to the Y-axis and parallel to the X-axis to obtain the corresponding wind speed of each detection coordinate. For the output voltage difference U _y in the Y-axis direction, the remote computer converts U _y into v _y according to the relationship model between the wind speed v in the positive direction of the Y-axis or the negative direction of the Y-axis and the output voltage difference U in step b, and records the data; Among them, when the value of U _y is positive, the wind speed is calculated using the Y-axis positive direction model with an error correction coefficient of k ₃ , and the wind direction is along the positive direction of the Y-axis; when the value of U _y is negative, the Y-axis with an error correction coefficient of k ₄ is used to calculate the wind speed. The negative direction model of the axis calculates the wind speed, and the wind direction is along the negative direction of the Y axis;

3) In order to detect the wind speed v _x in the X-axis direction, the polypropylene sheet 2 remains vertical, and the horizontal rotation mechanism rotates 90° clockwise, so that the polypropylene sheet 2 is perpendicular to the X-axis and parallel to the Y-axis. At this time, the original polypropylene sheet 2 position changes, but each detection coordinate still corresponds to a new polypropylene sheet 2; the output voltage difference U _x in the X-axis direction corresponding to each detection coordinate is obtained, and the remote computer terminal is positive according to the X-axis in step b. The relationship model between the wind speed v in the negative direction of the direction or the X-axis and the output voltage difference U, convert U _x to v _x , and record the data; where, when the value of U _x is positive, use the X-axis with an error correction coefficient of k ₃ The wind speed is calculated by the positive direction model, and the wind direction is along the positive direction of the X axis; when the value of U _x is negative, the wind speed is calculated by using the X axis negative direction model with an error correction coefficient of k ₄ , and the wind direction is along the negative direction of the X axis.

In the step c1, control the multi-stage hydraulic lifting cylinder 14 to adjust the detection height of the wind field detection device to realize wind field detection on different horizontal planes; by adjusting the distance between the wind measurement distance adjustment mechanism and the polypropylene sheet 2 on the support bar 4 , to realize the change of the measured wind distance.

A method for evaluating the uniformity of online wind field distribution using the described micro-strain-based wind field detection device, comprising the steps of:

a. Establish the three-dimensional coordinate system of the wind field detection device:

Adjust the wind field detection device to the initial state, and the polypropylene sheet 2 is in a horizontal state;

Set the center point of the rotating frame 1 on the horizontal plane where the polypropylene sheet 2 is located as the origin O of the three-dimensional coordinate system, the X axis is parallel to the support bar 4, the positive direction is backward, the Y axis is perpendicular to the support bar 4, the positive direction is to the left, and the Z axis is Vertical to the XOY horizontal plane, the positive direction is downward;

b. Establish a simplified relationship model between wind speed v and output voltage difference U in different wind directions:

b1. Set the anemometer at a certain test distance from the air outlet of the speed-adjustable fan, and measure n gradually increasing wind speeds v _i (i=0,1,2,3...n), and the wind speed range is 0～ 10m/s, wherein when v ₀ =0, adjust the resistance value of the voltage amplifier 3 so that the output voltage difference U is 0, that is, U ₀ =0;

b2. Use the blower to blow out the measured winds of n wind speeds v _i step by step to the polypropylene sheet 2 in any horizontal state along the positive direction of the Z axis and the negative direction of the Z axis respectively at the said test distance, and blow them respectively to the polypropylene sheet 2 in any horizontal state The polypropylene sheet 2 in any vertical state blows out the measured n wind speeds v _i gradually increasing wind along the positive direction of the Y axis and the negative direction of the Y axis; in the process, the corresponding voltage amplifier 3 is collected by the data acquisition card 10 data, obtain the output voltage difference U _i corresponding to the wind speed v _i in different winds, and finally obtain the positive direction of the Z axis, the negative direction of the Z axis, the positive direction of the Y axis, the negative direction of the Y axis, the positive direction of the X axis and the The relationship model between the wind speed v in the negative direction of the X-axis and the output voltage difference U; among them, the relationship model between the positive direction of the X-axis and the positive direction of the Y-axis is the same, and the relationship model between the negative direction of the X-axis and the negative direction of the Y-axis is the same; the difference will be obtained Perform polynomial fitting on n different wind speed values and output voltage difference signals in the wind direction, establish a model of wind speed v and output voltage difference U, and determine the error correction coefficient k _j :

v=k _j U(j=1,2,3,4) Formula 2

In the formula, the unit of wind speed v is m/s, the unit of output voltage difference U is V, k _j is the error correction coefficient of different wind directions, k ₁ is the wind direction calibration coefficient in the positive direction of Z-axis, and k ₂ is the wind vane in the negative direction of Z-axis Fixed coefficient, k ₃ is the wind direction calibration coefficient in the positive direction of the X and Y axes, and k ₄ is the wind direction calibration coefficient in the negative direction of the X and Y axes;

c. Evaluation of distribution uniformity of wind field:

Return the wind field detection device to the initial state, according to the target detection wind direction (x, y, z), calculate and determine the horizontal rotation angle α that should be adjusted by the horizontal rotation mechanism and the rotation angle of the support bar that should be adjusted by the support bar rotation mechanism through formula 5 and formula 6 beta;

In the formula, the unit of α and β is degree;

Then the first stepper motor 13 and the second stepper motor 34 respectively drive the horizontal rotation mechanism and the support bar rotation mechanism to rotate corresponding angles, so that the polypropylene sheet 2 of each detection coordinate is aligned with the wind direction (x, y) of the detected wind field. , z) vertical;

Each polypropylene sheet 2 cooperates with the strain gauge 41 to sense the bending deformation of the wind field, the resistance of the strain gauge 41 changes, and the output differential voltage changes. The data acquisition card 10 collects the voltage data of each voltage amplifier 3, and transmits the The output voltage difference signal U is transmitted to the remote computer terminal, and the remote computer terminal calculates the wind speed value corresponding to the mth polypropylene sheet 2 through formula 7

In the formula, is the wind speed value of the mth detection point, the unit is m/s; U _m is the output voltage difference of the mth detection point, the unit is V; β is the rotation angle of the support bar rotation mechanism, The direction is (x,y,z);

k _m is the error correction coefficient of the mth detection point, and its determination method is:

k _m U _m cosβ is , where U _m cosβ is the vertical component voltage of U _m . When U _m cosβ is positive, the wind speed in the vertical direction is calculated using the relationship model with the error correction coefficient of k _1. When U _m cosβ is negative, Then use the error correction coefficient k ₂ relational model;

k _m ^* U _m sinβ is The horizontal component velocity of U _m sinβ is the horizontal component voltage of U _m , when U _m sinβ is positive, the error correction coefficient is k ₃ relationship model is used to calculate the horizontal direction wind speed, when U _m sinβ is negative, the error correction is used The coefficient is k ₄ relational model;

Calculate the wind speed standard deviation of each polypropylene sheet 2 by formula 8, then calculate the wind speed distribution coefficient of variation of each polypropylene sheet 2 by formula 9:

In the formula, S is the standard deviation of the wind speed of each polypropylene sheet 2, is the average wind speed, is the wind speed value of the mth detection point, and the unit is m/s; q is the total number of detection points; CV is the variation coefficient of wind speed distribution at each point in the plane where the polypropylene sheet 2 is located, and its unit is %.

The concrete process of described step b2 is as follows:

b2.1. Move the fan to the test distance directly above any horizontal polypropylene sheet 2, and blow n winds with increasing wind speed v _i step by step downward in turn. When the wind speed is v _i , the polypropylene sheet 2 Cooperate with the strain gauge 41 to bend downward and deform, the resistance value of the strain gauge 41 changes, and the output differential voltage changes, the data acquisition card 10 collects the voltage data of the voltage amplifier 3, and transmits the output corresponding to different wind speeds v _i through the wireless transmission module 11 The voltage difference U _i is transmitted to the remote computer terminal for display and recording, and the remote computer terminal obtains the polynomial fitting relationship model between the wind speed v in the positive direction of the Z axis and the output voltage difference U according to formula 2: v=k ₁ U;

b2.2. Move the fan to directly below the polypropylene sheet 2 in any horizontal state. At the test distance, blow n winds with increasing wind speed v _i step by step. Other operations are the same as step b2.1. At this time, the voltage and wind speed are all negative values, and the polynomial fitting relationship model between the wind speed v in the negative direction of the Z axis and the output voltage difference U is obtained: v=k ₂ U;

b2.3. Change the fan to blow air along the positive direction of the Y-axis, the test distance remains unchanged, the support bar 4 is rotated 90° clockwise, and the polypropylene sheet 2 is adjusted vertically downward and perpendicular to the Y-axis. Other operations are the same as Step b2.1 is the same, at this time, the voltage and wind speed are all positive values, and the polynomial fitting relationship model between the wind speed v in the positive direction of the Y axis and the output voltage difference U is obtained: v=k ₃ U; the positive direction of the X axis and the positive direction of the Y axis The relational model is the same;

b2.4. Change the fan to blow air along the negative direction of the Y-axis. Other operations are the same as step b2.1. Combined relationship model: v=k ₄ U; the relationship model in the negative direction of the X axis is the same as that in the negative direction of the Y axis.

Control the multi-stage hydraulic lifting cylinder 14 to adjust the detection height of the wind field detection device to obtain wind speed values at more points, and substitute into formula 7 and formula 8 to calculate the standard deviation of wind speed and the coefficient of variation of wind speed distribution on each plane in the space.

Compared with prior art, the beneficial effect of the present invention is:

The invention is mainly used for online detection of stable wind fields generated by unmanned aerial vehicles, wind tunnel tests, air curtain machines, etc. in a hovering state, and can efficiently obtain the wind speed and wind direction distribution of the wind field. The wind field detection device uses a polypropylene sheet to simulate the curved blade under the wind field. The strain gauge is attached to the polypropylene sheet and bends accordingly. The resistance change of the strain gauge bending is converted into a differential pressure signal to detect the wind speed. It can quickly detect the wind speed in the X, Y, and Z directions of each point in the space, and can calculate the wind direction and wind speed value at each point; it can automatically adjust the detection height according to the purpose of the experiment, measure multiple points on the same horizontal plane and adjust the position of the measurement point, and quickly Measure the uniformity of wind speed at each point on the same horizontal plane and evaluate the characteristics of the entire wind field; high degree of automation and high detection efficiency can overcome the tediousness of multiple measurement processes, and can remotely observe and record real-time data online; and has high detection sensitivity and wind speed detection It has the characteristics of large range, high detection accuracy, high service life, low cost of detection parts, and easy replacement.

Description of drawings

Fig. 1 is the structural representation of the wind field detecting device based on micro-strain of the present invention;

Fig. 2 is a partially enlarged schematic diagram of the support bar rotation mechanism;

Fig. 3 is the structural representation that strain gage 41 is pasted on the polypropylene sheet 2;

Fig. 4 is a schematic diagram of a differential full bridge connection of strain gauges.

The reference signs therein are:

1 Swivel frame 2 Polypropylene sheet

3 voltage amplifier 4 support bar

5 fixed base 6 mobile base

7 Rotating bearing 8 Supporting spokes

9 power supply 10 data acquisition card

11 wireless transmission module 12 rotating disk

13 The first stepping motor 14 Multi-stage hydraulic lifting cylinder

15 displacement sensor 16 base

17 control module 18 first angle sensor

19 base moving groove 20 limit slide rail

21 move the inner rod 22 move the outer rod

23 clamping bolt 24 turn the inner sleeve rod

25 Turn the outer rod 26 Hexagon socket bolt

27 Hex nut 28 Washer

29 Base rail hole 30 Second angle sensor

31 rotating driven gear 32 driving gear

33 Turn the outer wheel 34 The second stepper motor

41 Strain gauge 42 Adhesive film

a First strain gauge b Second strain gauge

c third strain gauge d fourth strain gauge

O The origin of the three-dimensional coordinate system

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, a wind field detection device based on micro-strain includes a support bar rotation mechanism, a horizontal rotation mechanism, a wind measurement distance adjustment mechanism, an automatic height adjustment mechanism and a control mechanism.

The horizontal rotation mechanism and the support bar rotation mechanism together constitute an automatic wind direction adjustment unit. Wherein, the horizontal rotating mechanism includes a rotating frame 1 , a rotating disc 12 , a first stepping motor 13 and a first angle sensor 18 . The revolving frame 1 is a rectangular parallelepiped frame with a square cross-section, including an upper square frame and a lower square frame arranged horizontally, and four vertical frames respectively fixed between the four corners of the upper square frame and the lower square frame. connecting column.

The lower end surface of the rotating disk 12 is hinged and fixed on the output shaft of the first stepping motor 13 through a flange, and the edge of the rotating disk 12 is fixed to the lower square frame of the rotating frame 1 through a plurality of supporting spokes 8 . The two parts of the first angle sensor 18 are respectively fixed on the lower surface of the first stepping motor 13 and the rotating disk 12 .

Preferably, the edges of the rotating disc 12 are respectively fixed to the four corners of the lower square frame of the rotating frame 1 through four supporting spokes 8 .

The supporting bar rotation mechanism includes a supporting bar 4, a fixed base 5, a moving base 6, a rotating bearing 7, a second angle sensor 30, a rotating driven gear 31, a driving gear 32, a rotating outer wheel 33 and a second stepping motor 34. Two opposite beams in the upper square frame of the rotating frame 1 are provided with base moving slots 19 along the length direction of the beams, and the base moving slots 19 are provided with limiting slide rails 20 .

A pair of fixed bases 5 are respectively fixed in the middle of the base moving slots 19 of the two crossbeams, and even pairs of moving bases 6 can be horizontally moved through the base slide rail holes 29 provided at the bottom of the moving base 6. On the limiting slide rail 20 in the groove 19, and the even numbered pairs of mobile bases 6 are symmetrically distributed on the line between the two fixed bases 5.

Each fixed base 5 and each mobile base 6 are provided with rotating bearings 7; between the rotating bearings 7 of two corresponding fixed bases 5, and the rotation of every two corresponding mobile bases 6 A support bar 4 is fixedly connected between the bearings 7 . A plurality of polypropylene sheets 2 and a plurality of voltage amplifiers 3 corresponding to the polypropylene sheets 2 are arranged on each support bar 4, and the plurality of polypropylene sheets 2 on each support bar 4 are equidistant by n×n in the plane Array distribution. The surface of the polypropylene sheet 2 is pasted with a plurality of pairs of parallel strain gauges 41 alternately arranged in front and back through the sticking film 42 , and each strain gauge 41 is connected to the voltage amplifier 3 in a differential full-bridge connection.

As shown in Figure 2, the outer side of each fixed base 5 is provided with a rotating driven gear 31 connected with the rotating bearing 7 in the fixed base 5, and the outer side of each mobile base 6 is provided with a rotation driven gear 31 connected with the rotating bearing 7 in the fixed base 5. The rotating outer wheel 33 connected by the rotating bearing 7 in the seat 6; a rotating driven gear 31 on the same side is connected with a plurality of rotating outer wheels 33 by a length-adjustable rotating connecting rod. The driving gear 32 meshes with the driven gear 31, and the driving gear 32 is connected with the output shaft of the second stepper motor 34 fixed on the beam of the upper square frame of the rotating frame 1. When the second stepper motor 34 drives the driving gear 32 to rotate, the driving gear 32 drives the rotating driven gear 31 to rotate, and the rotating driven gear 31 drives the rotating outer wheel 33 to rotate synchronously by rotating the connecting rod, so that it can rotate with the rotating driven gear 31 and rotate The rotating bearing 7 connected with the outer wheel 33 rotates synchronously, thereby making the support bar 4 rotate synchronously. The two parts of the second angle sensor 30 are respectively fixed on the fixed base 5 and the rotating driven gear 31 .

Preferably, the rotating connecting rod includes a rotating inner sleeve rod 24 and two rotating outer sleeve rods 25 respectively sleeved at both ends of the rotating inner sleeve rod 24, and the inner rotating sleeve rod 24 and the rotating outer sleeve rod 25 are connected by hexagon socket bolts. 26. The hex nut 27 and the front and rear two spacers 28 are clamped and positioned, wherein the rotating inner sleeve rod 24 is riveted on the rotating driven gear 31, and the two rotating outer sleeve rods 25 are riveted on the two rotating outer wheels 33 respectively.

The wind measurement spacing adjustment mechanism is fixed between the fixed base 5 and the mobile base 6, and can change the relative distance between the mobile base 6 and the fixed base 5, thereby changing the distance between adjacent support bars 4. Relative distance to realize the change of the measured wind distance.

Preferably, the wind measuring distance adjustment mechanism includes a moving inner sleeve rod 21 and a moving outer sleeve rod 22 sleeved on the outside of the moving inner sleeve rod 21, the moving inner sleeve rod 21 can slide in the moving outer sleeve rod 22, and can be clamped The tightening bolt 23 is clamped and positioned; the end of the moving inner sleeve rod 21 and the end of the moving outer sleeve rod 22 are fixedly connected to the fixed base 5 and the moving base 6 respectively.

Preferably, both the moving inner sleeve rod 21 and the rotating inner sleeve rod 24 are marked with scales to facilitate the positioning of the sleeve rods.

The automatic height adjustment mechanism includes a multistage hydraulic lifting cylinder 14 , a displacement sensor 15 and a base 16 . The multistage hydraulic lift cylinder 14 is vertically installed on the base 16, and the piston rod end of the multistage hydraulic lift cylinder 14 is affixed to the bottom end of the first stepper motor 13; the displacement sensor 15 is fixed on the first step Enter the bottom of motor 13.

The interior of each lower hydraulic lifting cylinder in the multi-stage hydraulic lifting cylinder 14 is provided with a moving rail, and the bottom of each upper hydraulic lifting cylinder is provided with a rail groove that matches the moving rail, which limits the rotation of the hydraulic cylinder and makes Multistage hydraulic lift cylinder 14 can only lift vertically.

The control mechanism includes a power supply 9 arranged on a rotating disk 12 , a data acquisition card 10 , a wireless transmission module 11 and a control module 17 .

The strain gage 41 on each polypropylene sheet 2 is all connected with a voltage amplifier 3 by wire, and each voltage amplifier 3 is all connected with data acquisition card 10 by wire; Data acquisition card 10 can collect multiple groups of voltage data simultaneously, and through The wireless transmission module 11 transmits to the remote computer terminal to record and draw the wind field map.

The power supply 9 is each voltage amplifier 3, data acquisition card 10, wireless transmission module 11, first stepper motor 13, multi-stage hydraulic lifting cylinder 14, displacement sensor 15, control module 17, first angle sensor 18, The second angle sensor 30 and the second stepping motor 34 are powered.

The control module 17 controls the multi-stage hydraulic lifting cylinder 14, the first stepping motor 13 and the second stepping motor 34, receives the monitoring data of the displacement sensor 15, the first angle sensor 18 and the second angle sensor 30, and transmits the data via wireless The transmission module 11 communicates with the remote computer.

As shown in Figure 3, two pairs of strain gauges 41 parallel and arranged alternately in front and back are pasted on the surface of the polypropylene sheet 2 by pasting film 42, which are: the first strain gauge a, the second strain gauge b, the first strain gauge The three strain gauges c and the fourth strain gauge d; wherein, the first strain gauge a and the third strain gauge c are bonded on the front side, and the second strain gauge b and the fourth strain gauge d are bonded on the reverse side.

The strain gauge 41 is a strip-shaped strain gauge, preferably, the length of the strain gauge 41 is 5cm; the resistance value change is not obvious if the length is too short, and the area of the polypropylene sheet will increase if the length is too long, reducing the measurement accuracy . The strain gauge 41 is connected by a differential full bridge, and the circuit connection method is shown in FIG. 4 . Compared with the connection between the single bridge and the differential half bridge, it has superior sensitivity, and the accuracy of the measured voltage change is more accurate. Among them, the output voltage difference is U, the power supply voltage is E, the connection ports of the power supply and the strain gauge are connected to the voltage amplifier 3, the positive pole of the power supply is connected to the VCC terminal of the voltage amplifier 3, and the negative pole of the power supply is connected to the GND terminal. The two ends of E and U are respectively connected to the four interfaces of the P terminal of the voltage amplifier 3, and the out terminals of all the voltage amplifiers 3 are connected to the data acquisition card 10 to transmit the differential pressure signal U, and the data acquisition card 10 only needs one port to be connected to GND.

When there is no wind, the polypropylene sheet 2 is in a horizontal state, adjust the resistance of the voltage amplifier 3 so that the output voltage difference U is 0, when the wind direction is along the positive direction of the Z-axis of the three-dimensional coordinate system, each polypropylene sheet 2 and the strain gauge 41 are aligned Bending down, the first strain gauge a and the third strain gauge c pasted on the front are stretched, the resistance value increases, the second strain gauge b and the fourth strain gauge d pasted on the reverse side are compressed, the resistance value decreases, and the output voltage The difference U is positive; when the wind direction is along the negative direction of the Z axis, the strain gauges 41 are all bent upwards, the first strain gauge a and the third strain gauge c pasted on the front are compressed, and the resistance value decreases, and the second strain gauge pasted on the back b and the fourth strain gauge d are stretched, the resistance value increases, and the output voltage difference U is negative. Therefore, the positive or negative of the output voltage difference U represents the opposite wind direction. Theoretically, the relationship between the wind speed v and the output voltage difference U is:

In the formula, U is the output voltage difference, E is the voltage supplied by the power supply, E ^* is the calibration coefficient of the deformation model of the polypropylene sheet, K ^* is the relationship between the relative deformation of the length of the strain gauge and the relative deformation of the polypropylene sheet in the vertical direction Correlation coefficient, μ is the Poisson's ratio of the strain gauge material, r ₀ is the air density at the maximum wind speed, and v is the maximum wind speed that can be withstood. is the deformation amount of the polypropylene sheet in the vertical direction under the wind pressure state, the downward bending is a negative value, and the upward bending is a positive value, where r ₀ is the air density under the wind pressure state, v is the wind speed change, E ^* is The calibration coefficient of the polypropylene sheet deformation model in this state.

The working mode of the wind field detection device based on micro-strain:

Before detection, it is necessary to determine the target detection point. The target detection point must be a 3×3, 5×5 or 7×7 equidistant array point, the center point of the array is O, and the distance between two adjacent points is the detection distance d. Each point Arrange a group of polypropylene sheets 2 and voltage amplifiers 3, and correspondingly need a corresponding number of support bar rotation mechanisms and wind measurement spacing adjustment mechanisms, and stick them to the target position to fix them.

Taking FIG. 1 as an example, the arrangement is 3×3 equidistant, and the support bar rotation mechanism includes three support bars 4 . When adjusting the distance, the distance between the moving bases 6 on the left and right sides and the fixed base 5 in the middle is used to determine the distance between the wind measuring points. As shown in Figure 2, adjust the distance between the two bases to adjust the distance between the two support bars. The distance between the right side and the middle support bar 4 is equal to the distance between the moving base 6 on the right side and the fixed base 5, and is equal to the right side rotating outer wheel 33 at the same time. , rotation driven gear 31 and the distance of the riveting point center of rotation inner sleeve rod 24 and rotation outer sleeve rod 25 respectively. First loosen the two clamping bolts 23 and the inner hexagonal bolt 25 on the right side, and reach the target distance by changing the relative distance between the rotating inner sleeve rod 24 and the rotating outer sleeve rod 25, and then limit the movement of the rotating sleeve rod by tightening the inner hexagonal bolt 26 . In order to ensure the synchronous rotation of the right rotating outer wheel 33 and the rotating driven gear 31, the total length of cooperation between the moving outer sleeve rod 22 and the moving inner sleeve rod 21 should meet the target distance difference between the center of the rotating bearing 7 and the right side of the fixed base 6. The horizontal distance of the wall. Then tighten the clamping bolts 23 on both sides to limit the movement of the right side mobile base 6 . In the same way, the distance adjustment method of the left mobile base is the same as that of the right mobile base, and it is necessary to ensure that the two sides are arranged symmetrically.

In order to realize the automatic adjustment of the height of the rotating frame, first start the power supply 9, use the wireless transmission module 11 to receive the remote computer terminal signal, and the control module 17 transmits instructions to the multi-stage hydraulic lifting cylinder 14, pressurize to increase the height, decompress to reduce the height, The displacement sensor 15 monitors the height information in real time and transmits it to the control module 17, and then transmits it to the remote computer terminal for display in real time by the wireless transmission module 11, and stops lifting when the target height is reached.

When detecting the wind field, first return the wind field detection device to the initial state, start the power supply 9, and the remote computer terminal sends instructions to the control module 17 to control the multi-stage hydraulic lifting cylinder 14 to adjust to the detection height, and the displacement sensor 15 monitors the height in real time and passes The control module 17 feeds back to the remote computer terminal; the remote computer terminal sends instructions to the control module 17 to control the first stepping motor 13 and the second stepping motor 34 to return to the initial angle, and the first angle sensor 18 and the second angle sensor 30 respectively Real-time monitoring of the rotation of the horizontal rotation mechanism to the initial horizontal angle α ₀ and the rotation of the support bar rotation mechanism to the initial rotation angle β ₀ of the support bar and real-time feedback to the computer terminal through the control module 17, and the nine sets of polypropylene sheets 2 are rotated to the horizontal state and calibrated according to the coordinate system The coordinate system XYZ is established by means of the method; the wind speed in the Z-axis direction can be detected in the initial state, and the polypropylene sheet 2 is in the XOY plane; when the wind speed in the Y-axis direction is detected, the support bar rotation mechanism needs to rotate 90° clockwise, so that the polypropylene sheet 2 is in the XOZ Plane, the command sent by the computer terminal is sent to the control module 17 via the wireless transmission module 11, the control module 17 controls the second stepping motor 34 to rotate counterclockwise, the second stepping motor 34 drives the driving gear 32 to rotate, and the rotating driven gear 31 passes Rotate the inner sleeve rod 24 and rotate the outer sleeve rod 25 to drive the rotating outer wheels 33 on both sides to rotate synchronously, and the angle sensor 30 monitors the angle of rotation of the support bar 4 in real time, feeds back to the control module 17, and transmits it to the remote computer terminal for display through the wireless transmission module 11; When detecting the wind speed in the X-axis direction, after the support bar rotation mechanism rotates 90° clockwise, the horizontal rotation mechanism needs to be adjusted to rotate 90° clockwise. The polypropylene sheet 2 is in the YOZ plane, and the instruction sent by the computer terminal is sent via the wireless transmission module 11 to Control module 17, the control module 17 controls the first stepping motor 13 to rotate clockwise, drives the rotating disc 12 and the entire rotating frame 1 to rotate around the center of the output shaft of the first stepping motor 13, and the first angle sensor 18 monitors the rotating frame in real time 1 The angle of rotation is fed back to the control module 17, and transmitted to the remote computer for display through the wireless transmission module 11. Wherein, when the second stepper motor 34 rotates, the rotating inner sleeve rod 24 and the rotating outer sleeve rod 25 are always in a horizontal state, and the two rotating outer wheels 33 and the rotating driven gear 31 drive the respectively connected rotating bearing 7 and the supporting bar 4 to rotate the same angle, thereby ensuring that the three support bars 4 and the nine polypropylene sheets 2 are always parallel to each other, and the polypropylene sheets 2 are bent and deformed to different degrees with different wind pressures, and the greater the wind speed, the greater the deformation. The strain gauge changes with the wind field sensed by the polypropylene sheet 2. The greater the degree of bending of the strain gauge, the greater the change in resistance value, and the greater the output voltage difference U. The positive and negative of the output voltage difference U represent the opposite wind direction. The nine voltage amplifiers 3 transmit the differential pressure signal to the data acquisition card 10, and the data acquisition card 10 collects nine sets of data at the same time, and transmits them to a remote computer through the wireless transmission module 11 to record and draw a wind field map. After the detection is over, the polypropylene sheet 2 is rotated to a vertical state to prevent the polypropylene sheet from sagging due to the influence of gravity due to long-term non-use.

An online wind field detection method, comprising the steps of:

a. Establish the three-dimensional coordinate system of the wind field detection device:

The three-dimensional coordinate system of the calibration wind field detection device is shown in Figure 1, and the view in the X direction is the front view of the wind field detection device.

Adjust the wind field detection device to the initial state: the multi-stage hydraulic lifting cylinder 14 is at the highest height, the horizontal initial rotation angle of the first angle sensor 18 is α ₀ , the initial rotation angle of the support bar of the second angle sensor 30 is β ₀ , and the polypropylene sheet 2 in a horizontal state;

Set the center point of the rotating frame 1 on the horizontal plane where the polypropylene sheet 2 is located as the origin O of the three-dimensional coordinate system. The X axis is parallel to the support bar 4, and the positive direction is backward. The Y axis is perpendicular to the support bar 4, and the positive direction is to the left. The Z axis is perpendicular to the XOY horizontal plane, and the positive direction is downward. The coordinate system does not change with the rotation, and the clockwise and counterclockwise rotations of the horizontal rotation mechanism and the support bar rotation mechanism are respectively determined by observing along the Z and X positive directions.

b. Establish a simplified relationship model between wind speed v and output voltage difference U in different wind directions:

b1. Set the anemometer at a certain test distance (preferably 20 cm) from the air outlet of the speed-adjustable fan, and measure n gradually increasing wind speeds v _i (i=0,1,2,3...n), The wind speed ranges from 0 to 10 m/s. When v ₀ =0, adjust the resistance of the voltage amplifier 3 to make the output voltage difference U equal to 0, that is, U ₀ =0.

b2. Use the blower to blow out the measured winds of n wind speeds v _i step by step to the polypropylene sheet 2 in any horizontal state along the positive direction of the Z axis and the negative direction of the Z axis respectively at the said test distance, and blow them respectively to the polypropylene sheet 2 in any horizontal state The polypropylene sheet 2 in any vertical state blows out the measured n wind speeds v _i gradually increasing wind along the positive direction of the Y axis and the negative direction of the Y axis; in the process, the corresponding voltage amplifier 3 is collected by the data acquisition card 10 data, obtain the output voltage difference U _i corresponding to the wind speed v _i in different winds, and finally obtain the positive direction of the Z axis, the negative direction of the Z axis, the positive direction of the Y axis, the negative direction of the Y axis, the positive direction of the X axis and the The relationship model between the wind speed v in the negative direction of the X-axis and the output voltage difference U; because when detecting the wind speed in the X-axis, the polypropylene sheet 2 and the detection of the wind speed in the Y-axis direction belong to the vertical state, so the positive direction of the X-axis and the Y-axis The relationship model in the positive direction is the same, and the relationship model in the negative direction of the X axis is the same as that in the negative direction of the Y axis. Perform polynomial fitting on n different wind speed values obtained under different winds and the output voltage difference signal to establish the wind speed and the model of the output voltage difference U, and determine the error correction coefficient k _j :

v=k _j U(j=1,2,3,4) Formula 2

In the formula, v is the wind speed, the unit is m/s; U is the output voltage difference of the voltage amplifier 3, the unit is V; _kj is the error correction coefficient of different wind directions, and _k1 is the vertical positive direction (that is, the positive direction of the Z axis ) wind direction calibration coefficient, k ₂ is the wind direction calibration coefficient in the vertical negative direction (i.e. the negative direction of the Z axis), k ₃ is the wind direction calibration coefficient in the horizontal positive direction (i.e. the positive direction of the X and Y axes), and k ₄ is the horizontal negative direction (i.e. X, Y axis negative direction) wind direction calibration coefficient.

Preferably, since there is an interval between the fans of the fan, the generated wind speed v _i has small fluctuations, and the resulting output voltage difference U _i is a continuous value with slight changes. Taking multiple output voltage differences measured per unit time, whichever is the the mean value as the exact value U _i ;

The concrete process of described step b2 is as follows:

b2.1. Move the fan to the test distance (20 cm) directly above the polypropylene sheet 2 in any horizontal state, and blow n winds with increasing wind speed v _i step by step downwards in sequence. When the wind speed is v _i , The polypropylene sheet 2 cooperates with the strain gauge 41 to bend downward to deform, the resistance of the strain gauge 41 changes, and the output differential voltage changes, the data acquisition card 10 collects the voltage data of the voltage amplifier 3, and transmits the data of different wind speeds v through the wireless transmission module 11. The output voltage difference U _i corresponding to _i is transmitted to the remote computer terminal for display and recording, and the remote computer terminal obtains the polynomial fitting relationship model between the wind speed v in the positive direction of the Z axis and the output voltage difference U according to formula 2: v=k ₁ U.

b2.2. Move the fan to the test distance (20 cm) directly below the polypropylene sheet 2 in any horizontal state, and blow n winds with increasing wind speed v _i step by step, and other operations are the same as step b2. 1, the voltage and wind speed are all negative values at this time, and the polynomial fitting relationship model between the wind speed v in the negative direction of the Z axis and the output voltage difference U is obtained: v=k ₂ U.

b2.3. Change the fan to blow air along the positive direction of the Y-axis, the test distance remains unchanged, the support bar 4 is rotated 90° clockwise, and the polypropylene sheet 2 is adjusted vertically downward and perpendicular to the Y-axis. Other operations are the same as Step b2.1 is the same, at this time, the voltage and wind speed are all positive values, and the polynomial fitting relationship model between the wind speed v in the positive direction of the Y-axis and the output voltage difference U is obtained: v=k ₃ U. The positive direction of the X axis is the same as the relationship model of the positive direction of the Y axis.

b2.4. Change the fan to blow air along the negative direction of the Y-axis. Other operations are the same as step b2.1. Combined relational model: v=k ₄ U. The negative direction of the X-axis is the same as the relationship model of the negative direction of the Y-axis.

c. Wind field detection:

c1. Place the wind field detection device adjusted to the initial state at the detection position of the wind field to be measured, and simultaneously record the detection coordinates of each polypropylene sheet 2 in the three-dimensional coordinate system;

c2. Record the output voltage difference U _z of the Z-axis direction of the polypropylene sheet 2 in each horizontal state corresponding to each detection coordinate, the output voltage difference U _y of the Y-axis direction of the polypropylene sheet 2 in each vertical state, and The output voltage difference U _x in the direction of the X axis; according to the positive and negative values of U _z , U _y and U _x , select the positive direction of the Z axis, the negative direction of the Z axis, the positive direction of the Y axis, and the negative direction of the Y axis obtained in step b , the relationship model between the wind speed v in the positive direction of the X axis and the negative direction of the X axis and the output voltage difference U, and obtain the wind speed v _z in the direction of the Z axis corresponding to each detection coordinate, the wind speed v _y in the direction of the Y axis, and the voltage in the direction of the X axis wind speed v _x ;

c3. Calculate and obtain the wind speed and wind direction of each detection coordinate through formula 3 and formula 4 and wind speed

In the formula, v _z is the wind speed in the Z-axis direction, v _y is the wind speed in the Y-axis direction, and v _x is the wind speed in the X-axis direction, and the unit is m/s. It is a three-dimensional vector, containing wind direction and wind speed value information; v _x , v _y , v _z contain positive and negative direction information and wind speed.

The specific process of the step c2 is as follows:

1) The polypropylene sheet 2 in the horizontal state can detect the wind field velocity v _z in the Z-axis direction. The polypropylene sheet 2 corresponding to each detection coordinate cooperates with the strain gauge 41 to sense the bending deformation of the wind field, and the resistance value of the strain gauge 41 changes. When the output differential voltage changes, the data acquisition card 10 collects the voltage data of each voltage amplifier 3, and transmits the output voltage difference U _z in the Z-axis direction corresponding to each detection coordinate to the remote computer through the wireless transmission module 11, and the remote computer According to the relationship model between the wind speed v in the positive direction of the Z axis or the negative direction of the Z axis in step b and the output voltage difference U, the terminal converts U _z to v _z and records the data. Among them, when the value of U _z is positive, the wind speed is calculated using the relationship model in the positive direction of the Z axis with an error correction coefficient of k ₁ , and the wind direction is along the positive direction of the Z axis; when the value of U _z is negative, the relationship model with an error correction coefficient of k ₂ is used The Z-axis negative direction model calculates the wind speed, and the wind direction is along the negative direction of the Z-axis;

2) In order to detect the wind speed v _y in the Y-axis direction, the support bar 4 is rotated 90° clockwise, and the polypropylene sheet 2 is adjusted vertically downward and perpendicular to the Y-axis and parallel to the X-axis, and the detection coordinates can be obtained in the same way The corresponding output voltage difference U _y in the Y-axis direction, the remote computer converts U _y into v _y according to the relationship model between the wind speed v in the positive direction of the Y-axis or the negative direction of the Y-axis in step b and the output voltage difference U, and Record data. Among them, when the value of U _y is positive, the wind speed is calculated using the Y-axis positive direction model with an error correction coefficient of k ₃ , and the wind direction is along the positive direction of the Y-axis; when the value of U _y is negative, the Y-axis with an error correction coefficient of k ₄ is used to calculate the wind speed. The model in the negative direction of the axis calculates the wind speed, and the wind direction is along the negative direction of the Y axis.

3) In order to detect the wind speed v _x in the X-axis direction, the polypropylene sheet 2 remains vertical, and the horizontal rotation mechanism rotates 90° clockwise, so that the polypropylene sheet 2 is perpendicular to the X-axis and parallel to the Y-axis. At this time, the original polypropylene sheet 2 changes, but each detection coordinate still corresponds to a new polypropylene sheet 2; similarly, the output voltage difference U _x in the X-axis direction corresponding to each detection coordinate can be obtained, and the remote computer terminal can The relationship model between the wind speed v in the positive direction of the X-axis or the negative direction of the X-axis and the output voltage difference U, convert U _x to v _x , and record the data. Among them, when the value of U _x is positive, the wind speed is calculated using the positive X-axis model with an error correction coefficient of k ₃ , and the wind direction is along the positive direction of the X axis; when the value of U _x is negative, the X-axis with an error correction coefficient of k ₄ is used to calculate the wind speed. The negative axis model calculates the wind speed, and the wind direction is along the negative direction of the X axis.

Preferably, in the step c1, the detection height of the wind field detection device is adjusted by remotely controlling the multi-stage hydraulic lifting cylinder 14, so as to realize wind field detection at different levels.

Preferably, in the step c1, the wind distance measured is changed by adjusting the distance between the wind distance adjustment mechanism and the polypropylene sheets 2 on the support bar 4 .

When evaluating the wind field, the uniformity of the wind field is very important. In the wind tunnel test, the uniformity of the wind speed in the horizontal direction needs to be detected, and in the rotor airflow of the drone, the uniformity of the wind speed in the vertical direction needs to be detected. The method of the present invention The wind field detection device can detect any wind direction and speed, and evaluate the uniformity.

A method for evaluating the uniformity of online wind field distribution, comprising:

a. Establish the three-dimensional coordinate system of the wind field detection device:

The three-dimensional coordinate system of the calibration wind field detection device is shown in Figure 1, and the view in the X direction is the front view of the wind field detection device.

Adjust the wind field detection device to the initial state: the multi-stage hydraulic lifting cylinder 14 is at the highest height, the horizontal initial rotation angle of the first angle sensor 18 is α ₀ , the initial rotation angle of the support bar of the second angle sensor 30 is β ₀ , and the polypropylene sheet 2 in a horizontal state;

Set the center point of the rotating frame 1 on the horizontal plane where the polypropylene sheet 2 is located as the origin O of the three-dimensional coordinate system. The X axis is parallel to the support bar 4, and the positive direction is backward. The Y axis is perpendicular to the support bar 4, and the positive direction is to the left. The Z axis is perpendicular to the XOY horizontal plane, and the positive direction is downward. The coordinate system does not change with the rotation, and the clockwise and counterclockwise rotations of the horizontal rotation mechanism and the support bar rotation mechanism are respectively determined by observing along the Z and X positive directions.

b. Establish a simplified relationship model between wind speed v and output voltage difference U in different wind directions:

b1. Set the anemometer at a certain test distance (preferably 20 cm) from the air outlet of the speed-adjustable fan, and measure n gradually increasing wind speeds v _i (i=0,1,2,3...n), The wind speed ranges from 0 to 10 m/s. When v ₀ =0, adjust the resistance of the voltage amplifier 3 to make the output voltage difference U equal to 0, that is, U ₀ =0.

b2. Use the blower to blow out the measured winds of n wind speeds v _i step by step to the polypropylene sheet 2 in any horizontal state along the positive direction of the Z axis and the negative direction of the Z axis respectively at the said test distance, and blow them respectively to the polypropylene sheet 2 in any horizontal state The polypropylene sheet 2 in any vertical state blows out the measured n wind speeds v _i gradually increasing wind along the positive direction of the Y axis and the negative direction of the Y axis; in the process, the corresponding voltage amplifier 3 is collected by the data acquisition card 10 data, obtain the output voltage difference U _i corresponding to the wind speed v _i in different winds, and finally obtain the positive direction of the Z axis, the negative direction of the Z axis, the positive direction of the Y axis, the negative direction of the Y axis, the positive direction of the X axis and the The relationship model between the wind speed v in the negative direction of the X-axis and the output voltage difference U; because when detecting the wind speed in the X-axis, the polypropylene sheet 2 and the detection of the wind speed in the Y-axis direction belong to the vertical state, so the positive direction of the X-axis and the Y-axis The relationship model in the positive direction is the same, and the relationship model in the negative direction of the X axis is the same as that in the negative direction of the Y axis. The obtained n different wind speed values in different wind directions and the output voltage difference signal are polynomially fitted, the model of wind speed v and output voltage difference U is established, and the error correction coefficient k _j is determined:

v=k _j U(j=1,2,3,4) Formula 2

In the formula, v is the wind speed, the unit is m/s; U is the output voltage difference of the voltage amplifier 3, the unit is V; _kj is the error correction coefficient of different wind directions, and _k1 is the vertical positive direction (that is, the positive direction of the Z axis ) wind direction calibration coefficient, k ₂ is the wind direction calibration coefficient in the vertical negative direction (i.e. the negative direction of the Z axis), k ₃ is the wind direction calibration coefficient in the horizontal positive direction (i.e. the positive direction of the X and Y axes), and k ₄ is the horizontal negative direction (i.e. X, Y axis negative direction) wind direction calibration coefficient.

Preferably, since there is an interval between the fans of the fan, the generated wind speed v _i has small fluctuations, and the resulting output voltage difference U _i is a continuous value with slight changes. Taking multiple output voltage differences measured per unit time, whichever is the the mean value as the exact value U _i ;

The concrete process of described step b2 is as follows:

b2.1. Move the fan to the test distance (20 cm) directly above the polypropylene sheet 2 in any horizontal state, and blow n winds with increasing wind speed v _i step by step downwards in sequence. When the wind speed is v _i , The polypropylene sheet 2 cooperates with the strain gauge 41 to bend downward to deform, the resistance of the strain gauge 41 changes, and the output differential voltage changes, the data acquisition card 10 collects the voltage data of the voltage amplifier 3, and transmits the data of different wind speeds v through the wireless transmission module 11. The output voltage difference U _i corresponding to _i is transmitted to the remote computer terminal for display and recording, and the remote computer terminal obtains the polynomial fitting relationship model between the wind speed v in the positive direction of the Z axis and the output voltage difference U according to formula 2: v=k ₁ U.

b2.2. Move the blower to directly below the polypropylene sheet 2 in any horizontal state, and at the test distance (20 cm), blow up n winds with increasing wind speed v _i step by step, and other operations are the same as step b2. .1 is the same, the voltage and wind speed are all negative at this time, and the polynomial fitting relationship model between the wind speed v in the negative direction of the Z axis and the output voltage difference U is obtained: v=k ₂ U.

b2.3. Change the fan to blow air along the positive direction of the Y-axis, the test distance remains unchanged, the support bar 4 is rotated 90° clockwise, and the polypropylene sheet 2 is adjusted vertically downward and perpendicular to the Y-axis. Other operations are the same as Step b2.1 is the same, at this time, the voltage and wind speed are all positive values, and the polynomial fitting relationship model between the wind speed v in the positive direction of the Y-axis and the output voltage difference U is obtained: v=k ₃ U. The positive direction of the X axis is the same as the relationship model of the positive direction of the Y axis.

b2.4. Change the fan to blow air along the negative direction of the Y-axis. Other operations are the same as step b2.1. Combined relational model: v=k ₄ U. The negative direction of the X-axis is the same as the relationship model of the negative direction of the Y-axis.

c. Evaluation of distribution uniformity of wind field:

Return the wind field detection device to the initial state, according to the target detection wind direction (x, y, z), calculate and determine the horizontal rotation angle α that should be adjusted by the horizontal rotation mechanism and the rotation angle of the support bar that should be adjusted by the support bar rotation mechanism through formula 5 and formula 6 beta;

In the formula, the unit of α and β is degree.

Then the first stepper motor 13 and the second stepper motor 34 respectively drive the horizontal rotation mechanism and the support bar rotation mechanism to rotate corresponding angles, so that the polypropylene sheet 2 of each detection coordinate is aligned with the wind direction (x, y) of the detected wind field. , z) vertical; where, when α is positive, the horizontal rotation mechanism rotates clockwise; when α is negative, the horizontal rotation mechanism rotates counterclockwise; when β is positive, the support bar rotation mechanism rotates clockwise, and β is negative value, the support bar rotation mechanism rotates counterclockwise.

Each polypropylene sheet 2 cooperates with the strain gauge 41 to sense the bending deformation of the wind field, the resistance of the strain gauge 41 changes, and the output differential voltage changes. The data acquisition card 10 collects the voltage data of each voltage amplifier 3, and transmits the The output voltage difference signal U is transmitted to the remote computer terminal, and the remote computer terminal calculates the wind speed value corresponding to the mth polypropylene sheet 2 through formula 7

In the formula, is the wind speed value of the mth detection point, the unit is m/s; U _m is the output voltage difference of the mth detection point, the unit is V; β is the rotation angle of the support bar rotation mechanism, the unit is degree, The direction is (x,y,z).

k _m is the error correction coefficient of the mth detection point, and its determination method is:

k _m U _m cosβ is , where U _m cosβ is the vertical component voltage of U _m . When U _m cosβ is positive, the wind speed in the vertical direction is calculated using the relationship model with the error correction coefficient of k _1. When U _m cosβ is negative, Then use the error correction coefficient k ₂ relational model.

k _m ^* U _m sinβ is The horizontal component velocity of U _m sinβ is the horizontal component voltage of U _m , when U _m sinβ is positive, the error correction coefficient is k ₃ relationship model is used to calculate the horizontal direction wind speed, when U _m sinβ is negative, the error correction is used The coefficients are k ₄ relational models.

Calculate the wind speed standard deviation of each polypropylene sheet 2 by formula 8, then calculate the wind speed distribution coefficient of variation of each polypropylene sheet 2 by formula 9:

In the formula, S is the standard deviation of the wind speed of each polypropylene sheet 2, is the average wind speed, is the wind speed value of the mth detection point, and the unit is m/s; q is the total number of detection points; CV is the variation coefficient of wind speed distribution at each point in the plane where the polypropylene sheet 2 is located, and its unit is %.

Preferably, the detection height of the wind field detection device is adjusted by remotely controlling the multi-stage hydraulic lifting cylinder 14 to obtain wind speed values at more points, and the standard deviation of wind speed and the coefficient of variation of wind speed distribution of each plane in the space are calculated by substituting into formula 7 and formula 8 .

The smaller the variation coefficient CV and standard deviation S of the wind speed distribution, the more uniform the wind speed of the wind field. For wind fields such as wind tunnel tests that require high wind speed uniformity, if the coefficient of variation of wind speed distribution CV exceeds 10%, it is necessary to optimize the structure of the wind field to improve the uniformity of wind speed in the wind field.

Claims (10)

1. A wind field detection device based on micro-strain, characterized in that: the device includes a support bar rotation mechanism, a horizontal rotation mechanism, an wind measurement spacing adjustment mechanism, an automatic height adjustment mechanism and a control mechanism; Wherein, the horizontal rotation mechanism includes a rotating frame (1), a rotating disc (12), a first stepping motor (13) and a first angle sensor (18); the rotating frame (1) is a cross section of A square cuboid frame, including an upper square frame and a lower square frame arranged horizontally; The lower end surface of the rotating disk (12) is fixed on the output shaft of the first stepper motor (13), and the edge of the rotating disk (12) is connected to the lower layer of the rotating frame (1) through a plurality of supporting spokes (8). The square frame is affixed; the two parts of the first angle sensor (18) are respectively fixed on the lower end surface of the first stepping motor (13) and the rotating disc (12); The supporting bar rotation mechanism includes a supporting bar (4), a fixed base (5), a moving base (6), a rotating bearing (7), a second angle sensor (30), a rotating driven gear (31), a driving Gear (32), rotating outer wheel (33) and second stepper motor (34); Two relative beams in the upper floor square frame of described rotating frame (1) are provided with base moving groove along the length direction of beam (19); A pair of fixed bases (5) are respectively fixed in the middle of the base moving grooves (19) of the two beams, and even pairs of moving bases (6) can be horizontally moved in the base moving grooves (19), and even The mobile base (6) is distributed symmetrically with the line between the two fixed bases (5); Each fixed base (5) and each mobile base (6) are provided with rotating bearings (7); between the rotating bearings (7) of two corresponding fixed bases (5), and every two A support bar (4) is fixedly connected between the rotating bearings (7) of the two corresponding mobile bases (6); each support bar (4) is arranged with a plurality of polypropylene sheets (2) and a plurality of The polypropylene sheets (2) correspond to the voltage amplifiers (3), and a plurality of polypropylene sheets (2) on each support bar (4) are distributed in an n×n equidistant array in a plane; the polypropylene sheets ( 2) The upper surface is provided with multiple pairs of parallel strain gauges (41) that are alternately arranged in positive and negative directions, and each strain gauge (41) is connected to the voltage amplifier (3) in a differential full-bridge connection mode; The outside of each fixed base (5) is provided with a rotating driven gear (31) connected with the rotating bearing (7) in the fixed base (5), and the outer side of each mobile base (6) is provided with A rotating outer wheel (33) connected with the rotating bearing (7) in the mobile base (6); between a rotating driven gear (31) on the same side and a plurality of rotating outer wheels (33) through a length adjustable The rotating connecting rod is connected; the driving gear (32) is meshed with the rotating driven gear (31), and the driving gear (32) is connected to the second stepper on the beam of the upper square frame of the rotating frame (1). The output shaft of the motor (34) is connected; the two parts of the second angle sensor (30) are respectively fixed on the fixed base (5) and the rotating driven gear (31); The wind measuring distance adjustment mechanism is fixedly connected between the fixed base (5) and the mobile base (6); The height automatic adjustment mechanism includes a multistage hydraulic lifting cylinder (14), a displacement sensor (15) and a base (16); the multistage hydraulic lifting cylinder (14) is vertically installed on the base (16), and the multistage The piston rod end of the hydraulic lifting cylinder (14) is affixed to the bottom end of the first stepping motor (13); the displacement sensor (15) is fixed on the bottom end of the first stepping motor (13); The control mechanism includes a power supply (9), a data acquisition card (10), a wireless transmission module (11) and a control module (17) arranged on the rotating disk (12); Each voltage amplifier (3) is connected to the data acquisition card (10); the data acquisition card (10) can collect multiple sets of voltage data at the same time, and transmit them to the remote computer terminal through the wireless transmission module (11) to record and draw the wind field map ; The power supply (9) is respectively each voltage amplifier (3), data acquisition card (10), wireless transmission module (11), first stepper motor (13), multistage hydraulic lifting cylinder (14), displacement sensor (15), control module (17), the first angle sensor (18), the second angle sensor (30) and the second stepper motor (34) power supply; The control module (17) controls the multistage hydraulic lifting cylinder (14), the first stepping motor (13) and the second stepping motor (34), and receives the displacement sensor (15), the first angle sensor (18) and The monitoring data of the second angle sensor (30) is communicated with the remote computer terminal through the wireless transmission module (11). 2. The wind field detection device based on micro-strain according to claim 1, characterized in that: the support bar rotation mechanism includes two pairs of mobile bases (6), and the rotating connecting rod includes a rotating inner sleeve rod ( 24) and two rotating outer sleeve rods (25) that are respectively socketed in the two ends of the rotating inner sleeve rod (24), the rotating inner sleeve rod (24) and the rotating outer sleeve rod (25) pass through the inner hexagon bolt (26), hexagonal The nut (27) and the front and rear two spacers (28) are clamped and positioned, wherein the rotating inner sleeve rod (24) is riveted on the rotating driven gear (31), and the two rotating outer sleeve rods (25) are riveted on the two rotating outer sleeve rods (25) respectively. on a rotating outer wheel (33); the wind measuring distance adjustment mechanism includes a moving inner sleeve rod (21) and a moving outer sleeve rod (22) socketed on the outside of the moving inner sleeve rod (21), and the moving inner sleeve rod (21) It can slide in the movable outer rod (22) and be clamped and positioned by the clamping bolt (23); the end of the movable inner rod (21) and the end of the movable outer rod (22) are respectively fixed on the fixed base (5) and mobile base (6). 3. The wind field detection device based on micro-strain according to claim 1, characterized in that: the surface of the polypropylene sheet (2) is pasted with two pairs of parallel and alternately arranged front and back sides by pasting film (42). The strain gauges (41) are sequentially: the first strain gauge (a), the second strain gauge (b), the third strain gauge (c) and the fourth strain gauge (d); wherein, the first strain gauge (a) The third strain gauge (c) is pasted on the front side, and the second strain gauge (b) and the fourth strain gauge (d) are pasted on the reverse side. 4. an online wind field detection method utilizing the micro-strain wind field detection device according to claim 1, characterized in that: the method comprises the steps of: a. Establish the three-dimensional coordinate system of the wind field detection device: Adjust the wind field detection device to the initial state, and the polypropylene sheet (2) is in a horizontal state; Set the center point of the rotating frame (1) on the horizontal plane where the polypropylene sheet (2) is located as the origin O of the three-dimensional coordinate system, the X axis is parallel to the support bar (4), the positive direction is backward, and the Y axis is perpendicular to the support bar (4) , the positive direction is to the left, the Z axis is perpendicular to the XOY horizontal plane, and the positive direction is downward; b. Establish a simplified relationship model between wind speed v and output voltage difference U in different wind directions: b1. Set the anemometer at a certain test distance from the air outlet of the speed-adjustable fan, and measure n gradually increasing wind speeds v _i (i=0,1,2,3...n), and the wind speed range is 0～ 10m/s, wherein when v ₀ =0, adjust the resistance of the voltage amplifier (3) so that the output voltage difference U is 0, that is, U ₀ =0; b2. With the test distance, blow the measured n wind velocities v _i progressively increasing winds to the polypropylene sheet (2) in any horizontal state along the positive direction of the Z axis and the negative direction of the Z axis respectively, and To the polypropylene sheet (2) in any vertical state, blow out the measured n wind speeds v _i gradually increasing wind along the positive direction of the Y axis and the negative direction of the Y axis; in the process, through the data acquisition card (10) Collect the data of the corresponding voltage amplifier (3) to obtain the output voltage difference U _i corresponding to the downwind speed v _i of different winds, and finally obtain the positive direction of the Z axis, the negative direction of the Z axis, the positive direction of the Y axis, and the Y axis The relationship model between the wind speed v and the output voltage difference U in the negative direction, the positive direction of the X-axis, and the negative direction of the X-axis; where the relationship model between the positive direction of the X-axis and the positive direction of the Y-axis is the same, and the negative direction of the X-axis is the same as that of the negative direction of the Y-axis. The relationship model is the same; polynomial fitting is performed on n different wind speed values obtained in different wind directions and the output voltage difference signal, and the model of wind speed v and output voltage difference U is established, and the error correction coefficient k _j is determined: v=k _j U(j=1,2,3,4) Formula 2 In the formula, the unit of wind speed v is m/s, the unit of output voltage difference U is V, k _j is the error correction coefficient of different wind directions, k ₁ is the wind direction calibration coefficient in the positive direction of Z-axis, and k ₂ is the wind vane in the negative direction of Z-axis Fixed coefficient, k ₃ is the wind direction calibration coefficient in the positive direction of the X and Y axes, and k ₄ is the wind direction calibration coefficient in the negative direction of the X and Y axes; c. Wind field detection: c1. Place the wind field detection device adjusted to the initial state on the detection position of the wind field to be measured, and simultaneously record the detection coordinates of each polypropylene sheet (2) in the three-dimensional coordinate system; c2. Record the output voltage difference U _z of the Z-axis direction of the polypropylene sheet (2) in each horizontal state corresponding to each detection coordinate, and the output voltage of the Y-axis direction of the polypropylene sheet (2) in each vertical state difference U _y and the output voltage difference U _x in the direction of the X axis; according to the positive and negative values of U _z , U _y and U _x , select the positive direction of the Z axis, the negative direction of the Z axis, the positive direction of the Y axis, and the positive direction of the Y axis obtained in step b. The relationship model between the wind speed v in the negative direction of the Y-axis, the positive direction of the X-axis, and the negative direction of the X-axis and the output voltage difference U can obtain the wind speed v _z in the Z-axis direction corresponding to each detection coordinate, the wind speed v _y in the Y-axis direction and The wind speed v _x in the X-axis direction; c3. Calculate and obtain the wind speed and wind direction of each detection coordinate through formula 3 and formula 4 and wind speed In the formula, v _z is the wind speed in the Z-axis direction, v _y is the wind speed in the Y-axis direction, v _x is the wind speed in the X-axis direction, and the unit is m/s; It is a three-dimensional vector, containing wind direction and wind speed value information; v _x , v _y , v _z contain positive and negative direction information and wind speed. 5. The method according to claim 4, characterized in that: the specific process of the step b2 is as follows: b2.1. Move the fan to the test distance directly above the polypropylene sheet (2) in any horizontal state, and blow out n winds with increasing wind speed v _i step by step. When the wind speed is v _i , the polypropylene The sheet (2) cooperates with the strain gauge (41) to bend downward and deform, the resistance of the strain gauge (41) changes, and the output differential voltage changes, and the data acquisition card (10) collects the voltage data of the voltage amplifier (3), and passes The wireless transmission module (11) transmits the output voltage difference U _i corresponding to different wind speeds v _i to the remote computer for display and recording, and the remote computer obtains the polynomial fitting between the wind speed v in the positive direction of the Z axis and the output voltage difference U according to formula 2 Relational model: v=k ₁ U; b2.2. Move the fan to the test distance directly below the polypropylene sheet (2) in any horizontal state, and blow n winds with increasing wind speed v _i step by step, and the other operations are the same as step b2.1 , the voltage and wind speed are all negative values at this time, and the polynomial fitting relationship model between the wind speed v in the negative direction of the Z axis and the output voltage difference U is obtained: v=k ₂ U; b2.3. Change the fan to blow air along the positive direction of the Y axis. The test distance remains unchanged. The support bar (4) is rotated 90° clockwise, and the polypropylene sheet (2) is adjusted vertically downward and perpendicular to the Y axis. Other operations are the same as step b2.1. At this time, the voltage and wind speed are all positive values, and the polynomial fitting relationship model between the wind speed v in the positive direction of the Y-axis and the output voltage difference U is obtained: v=k ₃ U; the positive direction of the X-axis and The relationship model in the positive direction of the Y axis is the same; b2.4. Change the fan to blow air along the negative direction of the Y-axis. Other operations are the same as step b2.1. Combined relationship model: v=k ₄ U; the relationship model in the negative direction of the X axis is the same as that in the negative direction of the Y axis. 6. according to the method described in any one of claim 4-5, it is characterized in that: the specific process of described step c2 is as follows: 1) The polypropylene sheet (2) in the horizontal state can detect the wind speed v _z of the wind field in the Z-axis direction, and the polypropylene sheet (2) corresponding to each detection coordinate cooperates with the strain gauge (41) to sense the bending deformation of the wind field, and the strain The resistance value of the chip (41) changes, and the output differential voltage changes, and the data acquisition card (10) collects the voltage data of each voltage amplifier (3), and transmits the corresponding Z-axis direction of each detection coordinate through the wireless transmission module (11). The output voltage difference U _z is transmitted to the remote computer terminal, and the remote computer terminal converts U _z to v _z according to the relationship model between the wind speed v in the positive direction of the Z axis or the negative direction of the Z axis in step b and the output voltage difference U, and records data; where, when the value of U _z is positive, the wind speed is calculated using the Z-axis positive direction relationship model with an error correction coefficient of k ₁ , and the wind direction is along the positive direction of the Z axis; when the value of U _z is negative, the error correction coefficient is k The Z-axis negative direction model of ₂ calculates the wind speed, and the wind direction is along the negative direction of the Z-axis; 2) In order to detect the wind speed v _y in the Y-axis direction, the support bar (4) is rotated 90° clockwise, and the polypropylene sheet (2) is adjusted vertically downward and perpendicular to the Y-axis and parallel to the X-axis to obtain the The output voltage difference U _y in the Y-axis direction corresponding to the coordinates, the remote computer converts U _y into v _y according to the relationship model between the wind speed v in the positive direction of the Y-axis or the negative direction of the Y-axis in step b and the output voltage difference U, And record the data; among them, when the value of U _y is positive, use the Y-axis positive direction model with an error correction coefficient of k ₃ to calculate the wind speed, and the wind direction is along the positive direction of the Y-axis; when the value of U _y is negative, use the error correction coefficient of The Y-axis negative direction model of k ₄ calculates the wind speed, and the wind direction is along the Y-axis negative direction; 3) In order to detect the wind speed v _x in the X-axis direction, the polypropylene sheet (2) is kept vertical, and the horizontal rotation mechanism is rotated 90° clockwise so that the polypropylene sheet (2) is perpendicular to the X-axis and parallel to the Y-axis. At this time The position of the original polypropylene sheet (2) changes, but each detection coordinate still corresponds to a new polypropylene sheet (2); the output voltage difference U _x in the X-axis direction corresponding to each detection coordinate is obtained, and the remote computer According to the relationship model between the wind speed v and the output voltage difference U in the positive direction of the X-axis or the negative direction of the X-axis in step b, the terminal converts U _x to v _x and records the data; where the value of U _x is positive, use the error The wind speed is calculated by the _{X -} axis positive direction model with a correction factor of k ₃ , and the wind direction is along the positive direction of the X-axis; direction. 7. The method according to any one of claims 5-6, characterized in that: in the step c1, the multi-stage hydraulic lifting cylinder (14) is controlled to adjust the detection height of the wind field detection device, so as to realize the wind field of different levels Detection: the change of the measured wind distance is realized by adjusting the wind distance adjustment mechanism and the distance between the polypropylene sheets (2) on the support bar (4). 8. A method for evaluating the uniformity of online wind field distribution based on the micro-strain wind field detection device claimed in claim 1, characterized in that: the method comprises the steps of: a. Establish the three-dimensional coordinate system of the wind field detection device: Adjust the wind field detection device to the initial state, and the polypropylene sheet (2) is in a horizontal state; Set the center point of the rotating frame (1) on the horizontal plane where the polypropylene sheet (2) is located as the origin O of the three-dimensional coordinate system, the X axis is parallel to the support bar (4), the positive direction is backward, and the Y axis is perpendicular to the support bar (4) , the positive direction is to the left, the Z axis is perpendicular to the XOY horizontal plane, and the positive direction is downward; b. Establish a simplified relationship model between wind speed v and output voltage difference U in different wind directions: b1. Set the anemometer at a certain test distance from the air outlet of the speed-adjustable fan, and measure n gradually increasing wind speeds v _i (i=0,1,2,3...n), and the wind speed range is 0～ 10m/s, wherein when v ₀ =0, adjust the resistance of the voltage amplifier (3) so that the output voltage difference U is 0, that is, U ₀ =0; b2. With the test distance, blow the measured n wind velocities v _i progressively increasing winds to the polypropylene sheet (2) in any horizontal state along the positive direction of the Z axis and the negative direction of the Z axis respectively, and To the polypropylene sheet (2) in any vertical state, blow out the measured n wind speeds v _i gradually increasing wind along the positive direction of the Y axis and the negative direction of the Y axis; in the process, through the data acquisition card (10) Collect the data of the corresponding voltage amplifier (3) to obtain the output voltage difference U _i corresponding to the downwind speed v _i of different winds, and finally obtain the positive direction of the Z axis, the negative direction of the Z axis, the positive direction of the Y axis, and the Y axis The relationship model between the wind speed v and the output voltage difference U in the negative direction, the positive direction of the X-axis, and the negative direction of the X-axis; where the relationship model between the positive direction of the X-axis and the positive direction of the Y-axis is the same, and the negative direction of the X-axis is the same as that of the negative direction of the Y-axis. The relationship model is the same; polynomial fitting is performed on n different wind speed values obtained in different wind directions and the output voltage difference signal, and the model of wind speed v and output voltage difference U is established, and the error correction coefficient k _j is determined: v=k _j U(j=1,2,3,4) Formula 2 In the formula, the unit of wind speed v is m/s, the unit of output voltage difference U is V, k _j is the error correction coefficient of different wind directions, k ₁ is the wind direction calibration coefficient in the positive direction of Z-axis, and k ₂ is the wind vane in the negative direction of Z-axis Fixed coefficient, k ₃ is the wind direction calibration coefficient in the positive direction of the X and Y axes, and k ₄ is the wind direction calibration coefficient in the negative direction of the X and Y axes; c. Evaluation of distribution uniformity of wind field: Return the wind field detection device to the initial state, according to the target detection wind direction (x, y, z), calculate and determine the horizontal rotation angle α that should be adjusted by the horizontal rotation mechanism and the rotation angle of the support bar that should be adjusted by the support bar rotation mechanism through formula 5 and formula 6 beta; In the formula, the unit of α and β is degree; Then the first stepper motor (13) and the second stepper motor (34) drive the horizontal rotation mechanism and the support bar rotation mechanism to rotate corresponding angles respectively, so that the polypropylene sheet (2) of each detection coordinate is aligned with the detected wind field The wind direction (x, y, z) is vertical; Each polypropylene sheet (2) cooperates with the strain gauge (41) to sense the bending deformation of the wind field, the resistance value of the strain gauge (41) changes, and the output differential voltage changes, and the data acquisition card (10) collects the voltage of each voltage amplifier (3) Voltage data, and transmit the output voltage difference signal U to the remote computer terminal through the wireless transmission module (11), and the remote computer terminal calculates the wind speed value corresponding to the mth polypropylene sheet (2) through formula 7 In the formula, is the wind speed value of the mth detection point, the unit is m/s; U _m is the output voltage difference of the mth detection point, the unit is V; β is the rotation angle of the support bar rotation mechanism, The direction is (x,y,z); k _m is the error correction coefficient of the mth detection point, and its determination method is: k _m U _m cosβ is , where U _m cosβ is the vertical component voltage of U _m . When U _m cosβ is positive, the wind speed in the vertical direction is calculated using the relationship model with the error correction coefficient of k _1. When U _m cosβ is negative, Then use the error correction coefficient k ₂ relational model; k _m ^* U _m sinβ is The horizontal component velocity of U _m sinβ is the horizontal component voltage of U _m , when U _m sinβ is positive, the error correction coefficient is k ₃ relationship model is used to calculate the horizontal direction wind speed, when U _m sinβ is negative, the error correction is used The coefficient is k ₄ relational model; Calculate the wind speed standard deviation of each polypropylene sheet (2) by formula 8, then calculate the wind speed distribution coefficient of variation of each polypropylene sheet (2) by formula 9: In the formula, S is the wind speed standard deviation of each polypropylene sheet (2), is the average wind speed, is the wind speed value of the mth detection point, and the unit is m/s; q is the total number of detected points; CV is the coefficient of variation of wind speed distribution at each point in the plane where the polypropylene sheet (2) is located, and its unit is % . 9. The method according to claim 8, characterized in that: the specific process of the step b2 is as follows: b2.1. Move the fan to the test distance directly above the polypropylene sheet (2) in any horizontal state, and blow out n winds with increasing wind speed v _i step by step. When the wind speed is v _i , the polypropylene The sheet (2) cooperates with the strain gauge (41) to bend downward and deform, the resistance of the strain gauge (41) changes, and the output differential voltage changes, and the data acquisition card (10) collects the voltage data of the voltage amplifier (3), and passes The wireless transmission module (11) transmits the output voltage difference U _i corresponding to different wind speeds v _i to the remote computer for display and recording, and the remote computer obtains the polynomial fitting between the wind speed v in the positive direction of the Z axis and the output voltage difference U according to formula 2 Relational model: v=k ₁ U; b2.2. Move the blower to directly below the polypropylene sheet (2) in any horizontal state, and at the test distance, blow out n wind speeds v _i gradually increasing step by step, and other operations are the same as step b2.1 Similarly, the voltage and wind speed are all negative values at this time, and the polynomial fitting relationship model between the wind speed v in the negative direction of the Z axis and the output voltage difference U is obtained: v=k ₂ U; b2.3. Change the fan to blow air along the positive direction of the Y axis. The test distance remains unchanged. The support bar (4) is rotated 90° clockwise, and the polypropylene sheet (2) is adjusted vertically downward and perpendicular to the Y axis. Other operations are the same as step b2.1. At this time, the voltage and wind speed are all positive values, and the polynomial fitting relationship model between the wind speed v in the positive direction of the Y-axis and the output voltage difference U is obtained: v=k ₃ U; the positive direction of the X-axis and The relationship model in the positive direction of the Y axis is the same; b2.4. Change the fan to blow air along the negative direction of the Y axis. Other operations are the same as step b2.1. Combined relationship model: v=k ₄ U; the relationship model in the negative direction of the X axis is the same as that in the negative direction of the Y axis. 10. The method according to claim 8, characterized in that: control the multi-stage hydraulic lifting cylinder (14) to adjust the detection height of the wind field detection device to obtain more wind speed values, and substitute them into the calculation space of formula 7 and formula 8 The standard deviation of wind speed and the coefficient of variation of wind speed distribution in each plane.