阅读说明：本技术 卡尔曼滤波降雨量与压电式蒸发量一体化检测装置 (Kalman filtering rainfall and piezoelectric evaporation integrated detection device ) 是由 赵志浩 杨启良 周平 张健 苗为伟 于 2021-09-18 设计创作，主要内容包括：本发明公开了一种卡尔曼滤波降雨量与压电式蒸发量一体化检测装置,其包括机架机构、蒸发计、雨量计、雨水传感器；所述机架机构包括步进电机、机壳、斜拉索牵引线、支撑板Ⅰ、支撑板Ⅱ、机架挡板、滑杆；本发明将雨量计和蒸发计整合为结构紧凑、运行可靠的一体化检测装置,能根据天气变化自动切换有雨和无雨检测状态,有效降低了降雨天气对水面蒸发量检测的影响；能快速准确检测小雨及以上等级的降雨开始和停止信号；选用高精度压力传感器连续准确测量降雨量和水面蒸发量,并实现了远程监测。(The invention discloses a Kalman filtering rainfall and piezoelectric evaporation integrated detection device, which comprises a frame mechanism, an evaporometer, a rain gauge and a rain sensor, wherein the frame mechanism is used for detecting rainfall and piezoelectric evaporation; the frame mechanism comprises a stepping motor, a shell, a stay cable traction wire, a support plate I, a support plate II, a frame baffle and a slide rod; the rain gauge and the evaporometer are integrated into the integrated detection device which is compact in structure and reliable in operation, the states of rain detection and no-rain detection can be automatically switched according to weather changes, and the influence of rainfall weather on water surface evaporation capacity detection is effectively reduced; the rainfall starting and stopping signals of light rain and above levels can be rapidly and accurately detected; the high-precision pressure sensor is selected to continuously and accurately measure the rainfall capacity and the water surface evaporation capacity, and remote monitoring is realized.)

1. The utility model provides a karman filtering rainfall and piezoelectric type evaporation capacity integration detection device which characterized in that: comprises a frame mechanism, an evaporator (2), a rain gauge (6) and more than 3 rain sensors (1);

the frame mechanism comprises a stepping motor (3), a shell (5), a stay cable traction wire (14), a support plate I (15), a support plate II (22), a frame baffle (23) and slide rods (27), wherein one ends of the 4 slide rods (27) are fixed in the middle of the inside of the shell (5) through horizontal support seats (13), the other ends of the slide rods are fixed on the frame baffle (23) through the horizontal support seats, and an inner cavity at the lower part of the shell (5) is provided with a water storage tank (12); one end of a support plate I (15) is fixed on one side of a rack baffle plate (23), the other end of the support plate I is fixedly connected with the rack baffle plate (23) through a stay cable traction wire (14), and an evaporator (2) is placed on the support plate I (15); one end of a support plate II (22) is fixed on the other side of the rack baffle plate (23), the other end of the support plate II is fixedly connected with the rack baffle plate (23) through a stay cable traction wire, and the rain gauge (6) is placed on the support plate II (22); the stepping motor (3) is fixed on the shell (5), an output shaft of the stepping motor (3) is connected with one end of the transmission screw rod (4) through a fastening sleeve (19), and the other end of the transmission screw rod (4) is fixed on a frame baffle plate (23); the left side and the right side of the middle part of the shell (5) are provided with openings, and when the support plate I (15) is arranged in the shell (5), the support plate II (22) is arranged outside the shell (5); a rainwater splash-proof grid (7) is fixed on one side of the top of the casing (5) and is positioned on one side above the rain gauge (6), the rainwater sensor (1) is arranged on the top of the casing (5), the rainwater sensor (1) comprises a base, a spiral conical lead I (31) and a spiral conical lead II (32), and the spiral conical lead I (31) and the spiral conical lead II (32) are wound on the base alternately; the bottom of the evaporator (2) is communicated with a submersible pump (18) through a hose I (16), the submersible pump (18) is arranged in a water storage tank (12), an electromagnetic valve I (17) is arranged on the hose I (16), the outlet at the bottom of the rain gauge (6) is communicated with an electromagnetic valve II (20) through a hose II (21), a pressure sensor I (26) is arranged at the bottom of the evaporator, and a pressure sensor II (29) is arranged at the bottom of the rain gauge.

2. The Kalman filtering rainfall and piezoelectric evaporation integrated detection device of claim 1, wherein: a transparent observation door (8) is arranged on the casing (5).

3. The Kalman filtering rainfall and piezoelectric evaporation integrated detection device of claim 1, wherein: the bottom of the machine shell (5) is provided with a fixed base (11).

4. The Kalman filtering rainfall and piezoelectric evaporation integrated detection device of claim 1, wherein: the device also comprises a single chip microcomputer, wherein the single chip microcomputer is respectively connected with the stepping motor (3), the rainwater sensor (1), the pressure sensor I (26), the pressure sensor II (29), the electromagnetic valve I and the electromagnetic valve II; the single chip microcomputer comprises more than 3 Kalman filtering modules, a liquid level control module and a stepping motor control module;

the Kalman filtering module is used for collecting the electric signals output by the rainwater sensor, and then filtering by utilizing a Kalman filtering algorithm to remove the noise of the electric signals and give accurate rainfall starting and stopping signals;

the step motor control module receives a rainfall starting signal given by the Kalman filtering module and is used for driving the step motor to move the evaporometer into the shell, and the rain gauge is moved out of the shell; receiving a rainfall termination signal given by the Kalman filtering module, and driving a stepping motor to move the evaporometer out of the shell and move the rain gauge into the shell;

the liquid level control module is used for detecting liquid levels in the evaporation meter and the rain gauge, calculating evaporation capacity and rainfall capacity and controlling the addition and discharge of liquid in the evaporation meter and the rain gauge.

5. The Kalman filtering rainfall and piezoelectric evaporation integrated detection device of claim 4, wherein: the singlechip also comprises a wireless transmission module which is used for transmitting the singlechip data to a mobile phone or a computer.

Technical Field

The invention belongs to the technical field of water-saving irrigation and accurate irrigation, and particularly relates to a Kalman filtering rainfall and piezoelectric evaporation integrated detection device.

Background

Rainfall is the depth of water accumulated on the water level without evaporation, penetration and loss of liquid rainfall falling from the sky to the ground within a period of time. Soil evaporation capacity is the amount of water that evaporates from the soil surface into the atmosphere over a period of time. The farmland soil evaporation process after rain can be divided into 3 stages, namely a stable evaporation rate stage in which the soil evaporation intensity is close to the water surface evaporation intensity, an evaporation rate decreasing stage in which the soil evaporation intensity changes along with the water content, and a water vapor diffusion stage in which the soil moisture diffuses to the surface soil in a vapor state. The water surface evaporation capacity refers to the depth of water evaporated from a free water body without infiltration and loss in a period of time. Numerous scholars construct a mathematical model of farmland soil evaporation by water surface evaporation at home and abroad, so that indirect detection of farmland soil evaporation capacity is realized, and the method has the advantages of simplicity and easiness in operation, accurate detection result, stability and reliability in operation and the like.

For a long time, an evaporometer and a rain gauge are commonly used at home and abroad to respectively detect the water surface evaporation amount and the rainfall amount, but the problems of complex data processing, low automation degree, accumulated detection errors and the like exist. Therefore, many scholars are concerned about studying the integrated remote monitoring device of rainfall and water evaporation.

In the current monitoring system of facility agriculture, the integrated remote monitoring of rainfall and water surface evaporation has the following 4 defects:

(1) there is a lack of lightweight portable detection devices. In the current stage, the rainfall and the water surface evaporation are observed, most of which adopt a rain gauge and a large evaporator to directly detect or form an integrated detection system, and are mainly applied to a meteorological station or a hydrological station; the light-weight portable rainfall and water surface evaporation integrated detection device suitable for facility agriculture is lacked;

(2) the influence of rainfall weather on the detection of the evaporation capacity of the water surface is large. The water surface evaporation process of the existing evaporator is often influenced by the weather, and the detection result has larger error; the method for monitoring the water surface evaporation by covering and shielding rain is considered to be one of the ways capable of effectively reducing the influence of rainfall weather on the detection of the water surface evaporation amount, but has few applications;

(3) it is difficult to accurately detect the rainfall start-stop signal. When the capping and rain-shielding method is adopted to observe the evaporation capacity of the water surface of the evaporator, whether the accurate detection of the rainfall start-stop signal is the key to influence the timeliness of capping and uncapping is determined. The traditional rain sensor has lag response to the stop of rainfall and low detection sensitivity, the rainfall stop can be responded only after the rain on the surface of the sensor is naturally dried, the metal surface is easy to be oxidized, and the service life is short;

(4) and the remote online monitoring of the mobile phone is not realized. The integrated detection system of rainfall and water surface evaporation applied at the present stage can remotely transmit data, but does not realize data checking at any time and any place by using a mobile phone;

no report related to the content of the invention is found at present.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the integrated detection device for the rainfall capacity and the piezoelectric type evaporation capacity of the Kalman filtering, the integrated detection device has the advantages of high working efficiency, simple operation and low cost, can meet the detection precision requirements of national standards of the rainfall capacity and the evaporation capacity, improves the production quality and greatly saves the manpower.

The Kalman filtering rainfall and piezoelectric evaporation integrated detection device comprises a frame mechanism, an evaporometer, a rain gauge and a rain sensor; the frame mechanism comprises a stepping motor, a shell, a stay cable traction wire, a support plate I, a support plate II, a frame baffle and 4 sliding rods, wherein one end of each sliding rod is fixed at the middle part in the shell through a horizontal support seat, the other end of each sliding rod is fixed on the frame baffle through the horizontal support seat, and an inner cavity at the lower part of the shell is provided with a water storage tank; one end of a support plate I is fixed on one side of a rack baffle, the other end of the support plate I is fixedly connected with the rack baffle through a stay cable traction wire, and an evaporator is placed on the support plate I; one end of a support plate II is fixed on the other side of the rack baffle, the other end of the support plate II is fixedly connected with the rack baffle through a stay cable traction wire, and a rain gauge is placed on the support plate II; the stepping motor is fixed on the shell, an output shaft of the stepping motor is connected with one end of the transmission screw rod through the fastening sleeve, and the other end of the transmission screw rod is fixed on the frame baffle; the left side and the right side of the middle part of the shell are provided with openings, and when the support plate I is arranged in the shell, the support plate II is positioned outside the shell; a rainwater splash-proof grid is fixed on one side of the top of the casing and is positioned on one side above the rain gauge, a rainwater sensor is arranged on the top of the casing and comprises a base, a spiral conical lead I and a spiral conical lead II, and the spiral conical lead I and the spiral conical lead II are alternately wound on the base; evaporimeter bottom is passed through hose I and immersible pump intercommunication, and the immersible pump setting is provided with solenoid valve I on the hose I in the aqua storage tank, and the export of rain gauge bottom is passed through hose II and II intercommunications of solenoid valve, and pressure sensor I sets up in the evaporimeter bottom, and pressure sensor II sets up in the rain gauge bottom.

The transparent observation door is arranged on the casing, and the fixed base is arranged at the bottom of the casing.

The device also comprises a singlechip, wherein the singlechip is respectively connected with the stepping motor, the rainwater sensor, the pressure sensor I, the pressure sensor II, the electromagnetic valve I and the electromagnetic valve II; the single chip microcomputer comprises a Kalman filtering module, a liquid level control module and a stepping motor control module;

the Kalman filtering module is used for collecting the electric signals output by the rainwater sensor, and then filtering by utilizing a Kalman filtering algorithm to remove the noise of the electric signals and give accurate rainfall starting and stopping signals; removing electric signal noise by using a Kalman filtering algorithm and adopting a conventional method and a conventional flow;

after the rainwater is communicated with the spiral conical lead I and the spiral conical lead II, the loop resistance of a rainwater detection circuit is large, the resistance thermal noise is white noise, and the Kalman filtering module is adopted to reduce the white noise interference; sampling continuously-changed rainwater detection signals by using a Kalman filter, wherein the sampling period is 1s, and obtaining the optimal estimated value of the k moment by recursive estimation according to the electric signal estimated value of the detection signal at the k-1 moment and the detection value at the k moment to realize signal optimization, wherein the algorithm flow is shown in FIG. 6;

the Kalman filtering module estimates the electric signal according to the k-1 momentElectric signal estimation value for predicting k timeThe calculation equation is:

P(k|k-1)＝U·P(k-1|k-1)·UT+Q；

in the formula: u is a state transition matrix, and U is 1 because the change of the rainwater detection signals at adjacent moments is not large; v is a control matrix, u (k-1) is a state control quantity, and u (k-1) is 0; q is covariance of process excitation noise, P (k | k-1) is covariance corresponding to the electric signal estimation value at the moment k, and P (k-1| k-1) is covariance corresponding to the optimal electric signal estimation value at the moment k-1, wherein P (0|0) ═ 0; u shape^TIs the transposition of the matrix;

(2) the Kalman filtering module adopts the electric signal detection value z (k) at the moment k to correct the electric signal estimation value at the moment kThereby obtaining the value of the electric signal at the k momentThe calculation equation is:

λ(k)＝P(k|k-1)·H^T·[H·P(k|k-1)·H^T+R]^-1

P(k|k)＝[1-λ(k)·H]·P(k|k-1)；

in the formula: λ (k) is the kalman gain of the electrical signal at time k; p (k | k) is the covariance corresponding to the optimal estimation value of the electric signal at the time k; h is a measurement matrix; r is the covariance of the measurement noise, H^TIs a transpose of the measurement matrix;

due to the determination of the state transition matrix, the smaller the parameter Q is and the better the filtering convergence stability is when the parameter Q is not zero, the smaller the value when the parameter R is too small or too large is, the worse the filtering convergence stability is, but the larger the R value isThe faster the small filter converges; combining a filtering effect test result of the Kalman filtering module on the rainwater detection signal, and setting a parameter Q to be 10^-4R ═ 10; repeating the prediction process and the correction process, recursively obtaining a Kalman filtering signal of a single rainwater detection signal, effectively reducing the interference of resistance thermal noise generated in the detection process on the rainwater detection signal, and realizing smooth filtering;

in order to improve the fault tolerance of the rainfall starting and stopping signal judgment, more than 3 rainwater sensing modules with the same parameters are adopted to simultaneously detect rainfall, and more than 3 Kalman filtering modules are used for processing respectively to obtain more than 3 groups of Kalman filtering signals i (i is 1,2, 3.) with the value at the time k beingSince a single kalman filter takes about 0.2ms to operate for 1 time, more than 3 kalman filter modules operating sequentially may be considered to operate simultaneously; analyzing more than 3 Kalman filtering signals according to the following steps, and realizing the discrimination of rainfall starting and stopping signals;

(1) and acquiring a discrimination reference value. Simultaneously acquiring signal values of each Kalman filter at intervals of delta tRespectively serving as a judgment reference value of each Kalman filtering signal at the moment k, wherein k/delta t represents an integer division quotient; the system periodically samples the discrimination reference value of each Kalman filtering signal at intervals of delta t, and periodically discriminates the Kalman filtering signals at intervals of delta t, so that the delta t is determined as a discrimination period;

(2) and calculating a discrimination signal value. Subtracting the corresponding discrimination reference value from each Kalman filtering signal value at the k moment in the discrimination period to obtain the discrimination signal value at the k moment, wherein the calculation formula is as follows:

where yi (k) is the discrimination signal value of the Kalman filtering signal i at the moment k;the value of a Kalman filtering signal i at the moment k is obtained;a judgment reference value corresponding to the Kalman filtering signal i at the moment k;

(3) and determining upper and lower threshold limits. The discrimination signal values yi (K) at the time K are respectively compared with the upper threshold K₊The lower limit K-contrast analysis can dynamically judge the rising inflection point and the falling inflection point of each Kalman filtering signal so as to judge the rainfall starting and stopping signal; as the signal value at the beginning or the stopping of rainfall can rapidly descend or ascend, the change gradient of the Kalman filtering signal value at the stage per second is at least 1, namely, the change amplitude of the Kalman filtering signal value is at least the value of a discrimination period within the discrimination period delta t at the beginning or the stopping of rainfall, so that K₊Taking a positive value of delta t, and taking a negative value of delta t by K-;

(4) and judging a rainfall starting and stopping signal. If at least 2 Kalman filtering signals satisfy y at the moment k_i(k)＜K_-When the judgment signal enters a descending inflection point from the moment k, a rainfall starting signal is transmitted to the stepping motor control module; if at least 2 Kalman filtering signals satisfy y at the moment k_i(k)＞K₊When the judgment signal enters the rising inflection point from the moment k, the rainfall stop signal is transmitted to the stepping motor control module; the rainfall starting or stopping is judged for a plurality of times continuously, namely, only 1 time of rainfall starting and stopping signals are transmitted in the 1-time rainfall process judged by the system.

The dynamic analysis of the whole rainfall process can be completed by repeating the steps, and the rainfall starting and stopping signal is judged.

The step motor control module receives a rainfall starting signal given by the Kalman filtering module and is used for driving the step motor to move the evaporometer into the shell, and the rain gauge is moved out of the shell; receiving a rainfall termination signal given by the Kalman filtering module, and driving a stepping motor to move the evaporometer out of the shell and move the rain gauge into the shell;

the liquid level control module is used for detecting liquid levels in the evaporation meter and the rain gauge, calculating evaporation capacity and rainfall capacity and controlling the addition and discharge of liquid in the evaporation meter and the rain gauge.

The single chip microcomputer also comprises a wireless transmission module which is used for transmitting the data of the single chip microcomputer to a mobile phone or a computer.

When the device is used, the device is fixed in a field to be monitored, the system is initialized after the device is electrified, the single chip drives the stepping motor to completely move the rain gauge into the shell, the evaporator is moved out of the shell, the submersible pump is started to inject initial water quantity into the evaporator, the initial liquid level heights in the evaporator and the rain gauge are recorded, and the device enters a rain-free detection state; if the rain sensor does not detect the rainfall weather, the system always keeps a no-rain detection state, and after a period of time, the liquid level height in the evaporator is detected, and the water surface evaporation amount in the time period is output after the liquid level reduction value is analyzed and judged; if the rain sensor detects that rainfall begins, the stepping motor is driven to completely move the rain gauge out of the shell cavity, the evaporator moves into the shell cavity along with the rain gauge, and simultaneously enters a rain detection state, after the rain sensor detects that the rainfall stops, the liquid level height in the rain gauge is detected, and the rainfall is output after the liquid level increase value is analyzed and judged. After the rainfall stops, the system opens the electromagnetic valve II to discharge the liquid in the rain gauge into the water storage tank for storage, and the rainfall-free detection state is entered. The liquid level height in evaporimeter and the rain gauge adopts pressure sensor to detect, utilizes piezoelectric effect, converts the water pressure in evaporimeter and the rain gauge into the signal of telecommunication output, becomes the liquid level height in the container through voltage signal fitting to the liquid level condition in the decision-maker utilizes the liquid level difference value can draw rainfall or surface of water evaporation capacity.

The invention has the beneficial effects that: the rainfall gauge and the evaporometer are integrated into an integrated detection device which has compact structure and reliable operation, and the states of rain detection and no rain detection can be automatically switched according to the weather change, thereby effectively reducing the influence of the rainfall weather on the detection of the water surface evaporation capacity; the rainfall starting and stopping signals of light rain and above levels can be rapidly and accurately detected; a high-precision weighing type liquid level sensor is selected to continuously and accurately measure rainfall capacity and water surface evaporation capacity, and remote monitoring of a mobile phone is realized.

Drawings

FIG. 1 is a schematic view of the apparatus of the present invention;

FIG. 2 is a schematic view of a part of the structure of the apparatus of the present invention;

FIG. 3 is a schematic view of a part of the frame mechanism of the apparatus of the present invention;

FIG. 4 is a schematic view of a part of the frame mechanism of the apparatus of the present invention;

FIG. 5 is a schematic view of a rain sensor structure;

FIG. 6 is a schematic view of a Kalman filtering module algorithm flow;

FIG. 7 is a schematic control flow chart of the apparatus of the present invention;

FIG. 8 is a diagram illustrating a Kalman filtering signal processing result according to the present invention;

in the figure: 1-rain sensor; 2-an evaporometer; 3-a step motor; 4-driving a screw rod; 5-a machine shell; 6-a rain gauge; 7-a rainwater splash barrier; 8-transparent viewing doors; 9-fixing the loose-leaf I; 10-fixing the loose-leaf II; 11-a stationary base; 12-a water storage tank; 13-horizontal support seat; 14-stay cable traction lines; 15-support plate I; 16-hose I; 17-a solenoid valve I; 18-a submersible pump; 19-a fastening sleeve; 20-a solenoid valve II; 21-hose II; 22-support plate II; 23-a rack baffle; 24-evaporating dish rain-receiving port; 25-adapter I; 26-pressure sensor I; 27-a slide bar; 28-adapter II; 29-pressure sensor ii; 30-a rainfall barrel rain bearing port; 31-a spiral conical wire I; 32-spiral conical wire II.

Detailed Description

The present invention is further illustrated in detail by the following figures and examples, but the scope of the present invention is not limited to the above, and the examples are all conventional methods unless otherwise specified; the control mode or method of the single chip microcomputer is a conventional method if no special description is provided;

example 1: as shown in fig. 1-5, the kalman filter rainfall and piezoelectric evaporation integrated detection device comprises a frame mechanism, an evaporometer 2, a rain gauge 6 and 3 rain sensors 1; the frame mechanism comprises a stepping motor 3, a shell 5, a stay cable traction wire 14, a support plate I15, a support plate II 22, a frame baffle 23 and slide rods 27, wherein one end of each of the 4 slide rods 27 is fixed in the middle of the shell 5 through a horizontal support seat 13 and a bolt, the other end of each of the 4 slide rods 27 is fixed on the frame baffle 23 through the horizontal support seat and the bolt, an inner cavity in the lower part of the shell 5 is provided with a water storage tank 12, the left side and the right side of the middle of the shell 5 are provided with openings, and a transparent observation door 8 is arranged on the shell 5 through a fixed hinge I9 and a fixed hinge II 10; one end of a support plate I15 is fixed on one side of a rack baffle plate 23, the other end of the support plate I is fixedly connected with the rack baffle plate 23 through 2 stay cable traction wires 14, an evaporator 2 is placed on the support plate I15, the evaporator 2 comprises an evaporation dish rain bearing opening 24, and a pressure sensor I26 is arranged at the bottom of the evaporator 2; one end of a support plate II 22 is fixed on the other side of the rack baffle plate 23, the other end of the support plate II is fixedly connected with the rack baffle plate 23 through 2 stay cable traction lines, a rain gauge 6 is placed on the support plate II 22, the rain gauge 6 comprises a rain gauge barrel rain bearing port 30, and a pressure sensor II 29 is arranged at the bottom of the rain gauge; the stepping motor 3 is fixed on the shell 5, the output shaft of the stepping motor 3 is connected with one end of a transmission screw rod 4 through a fastening sleeve 19, and the other end of the transmission screw rod 4 is fixed on a frame baffle plate 23; when the support plate I15 is arranged in the shell 5, the support plate II 22 is arranged outside the shell 5; a rainwater splash-proof grid 7 is fixed on one side of the top of the machine shell 5 and is positioned on one side above the rain gauge 6, the rainwater sensor 1 is arranged on the top of the machine shell 5, the rainwater sensor 1 comprises a base, a spiral conical lead I31 and a spiral conical lead II 32, and the spiral conical lead I31 and the spiral conical lead II 32 are alternately wound in parallel in a lead groove of the base and are not in contact with each other; the bottom of the evaporator 2 is communicated with a submersible pump 18 through a conversion joint I25 and a hose I16, the submersible pump 18 is arranged in a water storage tank 12, an electromagnetic valve I17 is arranged on the hose I16, and the outlet at the bottom of the rain gauge 6 is communicated with an electromagnetic valve II 20 through a conversion joint II 28 and a hose II 21; the bottom of the machine shell 5 is provided with 8 fixed bases 11 through which the machine shell is fixed on the ground; the rainwater splash-proof grid 7 is made of high-density polylactide; the evaporometer 2 and the rain gauge 6 are made of type 304 stainless steel.

Example 2: the device of the embodiment has the same structure as that of the embodiment 1, and is different from the device of the embodiment 1 in that the device further comprises a single chip microcomputer, wherein the single chip microcomputer is respectively connected with the stepping motor 3, the rainwater sensor 1, the pressure sensor I26, the pressure sensor II 29, the electromagnetic valve I and the electromagnetic valve II; the single chip microcomputer comprises 3 Kalman filtering modules, a liquid level control module, a stepping motor control module and a wireless transmission module; the Kalman filtering module is used for collecting the electric signals output by the rainwater sensor, and then filtering by utilizing a Kalman filtering algorithm to remove the noise of the electric signals and give accurate rainfall starting and stopping signals; the step motor control module receives a rainfall starting signal given by the Kalman filtering module and is used for driving the step motor to move the evaporometer into the shell, and the rain gauge is moved out of the shell; receiving a rainfall termination signal given by the Kalman filtering module, and driving a stepping motor to move the evaporometer out of the shell and move the rain gauge into the shell; the liquid level control module is used for detecting liquid levels in the evaporation meter and the rain gauge, calculating evaporation capacity and rainfall capacity and controlling the addition and discharge of liquid in the evaporation meter and the rain gauge; the wireless transmission module is used for transmitting the singlechip data to a mobile phone or a computer.

As shown in fig. 7, when the device is used, the casing 5 of the device is fixedly connected with the horizontal ground to be detected through the fixed base 11, the system is initialized after the device is powered on, the singlechip drives the stepping motor 3 to completely move the rain gauge 6 into the casing 5, the evaporator 2 is moved out of the casing, the submersible pump 18 is started to inject initial water into the evaporator, the initial liquid level heights in the evaporator and the rain gauge are recorded, and the device enters a rain-free detection state; if the rain sensor does not detect the rainfall weather, the system always keeps a no-rain detection state, and after a period of time, the liquid level height in the evaporator is detected, and the water surface evaporation amount in the time period is output after the liquid level reduction value is analyzed and judged; if the rain sensor detects that rainfall begins, the stepping motor 3 is driven to completely move the rain gauge out of the shell cavity, the evaporometer moves into the shell cavity along with the rain gauge, and simultaneously enters a rain detection state, after the rain sensor 1 detects that the rainfall stops, the liquid level height in the rain gauge is detected, and the rainfall is output after the liquid level increase value is analyzed and judged. After the rainfall stops, the system opens the electromagnetic valve II to discharge the liquid in the rain gauge into the water storage tank for storage, and the rainfall-free detection state is entered.

The liquid level heights in the evaporator and the rain gauge are detected by adopting pressure sensors, the water pressure in the evaporator and the rain gauge is converted into an electric signal to be output by utilizing a piezoelectric effect, the liquid level height in the container is fitted through a voltage signal, so that the liquid level condition in the device is judged, and the rainfall or the water surface evaporation can be obtained by utilizing a liquid level height difference value;

(1) before the system starts liquid level detection, the liquid level in the evaporator reaches a set value through the submersible pump 18; the liquid level in the rain gauge reaches the lowest value through the electromagnetic valve II 20;

(2) after the system is started and the liquid level is detected, the evaporation capacity of the water surface can be calculated according to the liquid level change of the evaporator

E_W＝L_EI-L_EA-(L_RI-L_RT)

In the formula E_WThe water surface evaporation capacity is mm; l is_EIThe liquid level of the evaporating dish is mm before starting liquid level detection; l is_EAThe liquid level of the evaporating dish after the timing time is reached is mm; l is_RIThe liquid level of the evaporating dish at the beginning of rainfall is mm; l is_RTThe liquid level is mm after the evaporating dish is completely moved into the cavity of the machine shell.

The rainfall can be calculated according to the liquid level change of the rain gauge as

R_P＝L_RB-L_RA+(L_RI-L_RT)

In the formula R_PIs the rainfall, mm; l is_RBThe liquid level of the rainfall barrel at the beginning of rainfall is mm; l is_RAIs the liquid level of the rainfall barrel when the rainfall stops, and is mm.

The singlechip outputs 1 pulse signal, and the stepping motor rotates 1 step angle (1.8 degrees), so the stepping motor needs the singlechip to output 200 pulse signals when finishing 360-degree angular displacement. Under the drive of a transmission screw rod with a lead of 14mm, a stepping motor rotates for 1 circle (360-degree angular displacement), and the transmission screw rod drives a rack baffle plate for 14 mm; moving the bracket from the leftmost end to the rightmost end of the housing cavity by 265mm, wherein the stepping motor needs to rotate 265/14-18.9 circles and needs to output 200 × 18.9-3780 pulses; after the device is electrified, the stepping motor is driven to rotate forwards to move the support leftwards, and when the support triggers the limit switch, the stepping motor stops rotating to realize support resetting. When rainfall begins, the stepping motor is driven to rotate reversely, and the rack baffle is moved to the rightmost side in the shell; when the rainfall stops, the stepping motor is driven to rotate forwards, and the rack baffle is moved to the leftmost side in the shell.

Simulation detection test of rainfall and water surface evaporation capacity:

setting the observation ranges of the simulated rainfall and the water surface evaporation liquid level to be 15-170 mm and 10-70 mm respectively; setting the simulated rainfall capacity and the water surface evaporation liquid level to be 11 levels, wherein the test scheme is shown in table 1; simulating rainfall intensity to be light rain, and simulating 3 continuous stages of no rainfall, continuous rainfall and rainfall stop for 10min respectively;

TABLE 1 rainfall evaporation integrated device's accuracy test scheme

The test was carried out according to the following procedure, each set of tests was repeated 3 times for a total of 11 sets of 33 tests;

(1) in the stage of no rainfall, from 0s to the moment before rainfall, the wires I and II are in a disconnected state, and the voltage division end outputs 5V power supply voltage; from 0s to the time before the start of rainfall in fig. 8, the value of the rain detection signal is maintained at 1023 and is stable; the initial liquid level system value of the evaporator of the device is set according to the experimental scheme, and after the system is reset, the evaporator automatically adds water from a water storage tank to a set liquid level value through an electromagnetic valve I and a submersible pump;

(2) at the beginning of rainfall, the rainwater connects the wires I and II, the pull-up resistor starts to divide the voltage, the output voltage of the voltage dividing end is reduced, the value of a rainwater detection signal in the graph 8 is suddenly reduced from 1023, and when a falling inflection point appears in the signal, the rainfall starting moment is the moment, and the rain gauge is moved out of the shell by the device. According to the test scheme, tap water with a corresponding amount is measured by using a special measuring cylinder of a rain gauge, then the spray head is used for simulating light rain, a small amount of water is randomly added into the evaporator before the evaporator of the device is completely moved into a cavity of a shell in the test process, the rest amount of water is slowly added into the rain gauge, and the condition that rain water splashes into the shielded evaporator in the rain falling process is simulated;

(3) in the continuous rainfall stage, water is accumulated in a wire groove of a base of the rain sensor, so that the resistance between the wires I and II is close to the minimum value; in fig. 8, the value of the rain detection signal is nearly minimum, but the water accumulation amount is changed by the rain splash, so that the resistance value between the wires i and ii is changed, and the signal has small amplitude fluctuation and detection value noise; the light-colored curve in fig. 8 is the true detected electrical signal value, and the black solid-line curve in fig. 8 is the electrical signal value after kalman filtering;

(4) in the stage of stopping rainfall, accumulated water in a wire guide groove of a base of the rain sensor is discharged, the resistance value between the wires I and II is increased, the output voltage of a voltage dividing end is increased, the rain detection signal value is rapidly increased in a short time in the graph 8, the rising inflection point of the signal is the moment of stopping rainfall, the device moves the evaporator out of the shell, then the accumulated water discharge rate is reduced, and the rain detection signal value is slowly increased and approaches to the maximum value of 1023; a dropper is used for taking out 2mm of water from an evaporator of the device, and the water surface evaporation process is simulated;

(5) the detection values of the rainfall capacity and the water surface evaporation capacity are displayed through the mobile phone, the receiving success rate, the detection error and the detection stability of the rainfall capacity and the water surface evaporation capacity of the device are statistically analyzed, and the operation accuracy and the stability of the device are tested.

The test results are shown in table 2, and the results show that the standard deviation of the system values of the rainfall and the water surface evaporation is not obvious, the standard deviation ranges are 0.06-0.38 and 0.01-0.09 s respectively, and the detection result of the device is relatively stable. The detection error range of the rainfall and the water surface evaporation capacity is-0.73-0.71 and-2.50-2.00 percent;

TABLE 2 simulation test results of rainfall evaporation integrated device

Field test

In order to verify the adaptability of the device to the outdoor environment, a field test is carried out in a pseudo-ginseng field of modern agriculture engineering institute of university of Kunming technology at 12/1/2021/3/1 in 2020, the average outdoor temperature is 11.2 ℃, the average humidity is 18.3 percent, the wind power is mainly 1-2 grade, and the rainfall weather is mainly small rain. The test device is stably fixed in an open environment without shielding around a field;

before the test starts, the initial test liquid level system value of the evaporator of the device is set to be 20mm, and 20mm tap water is measured and injected into a traditional evaporating dish; measuring the daily rainfall and the daily water surface evaporation in the previous 24h time period by using a measuring cylinder at 08:00 a day;

in order to test the performance of the device, 9d test data of rainfall weather is screened out, the detection result of the device is compared with the manual detection result for analysis, and the analysis result is shown in table 3;

the rainfall detected by the device is higher than the manual detection result, the relative error of the rainfall detection result is reduced along with the increase of the rainfall, and the relative error range is 1.42-11.11%, which probably is because the device adopts a funnel-type rain bearing device without leakage, so that the interception of the rain bearing device to the rain is reduced.

The water surface evaporation amount detected by the device is lower than an artificial detection result, the relative error of the water surface evaporation amount detection result is increased along with the increase of rainfall, and the relative error range is-5.20 to-1.34 percent, which may be that the detection result of the traditional rainfall gauge is smaller, so that the artificial detection value of the water surface evaporation amount after the rainfall is deducted is larger, and meanwhile, an artificial reading error exists.

By integrating the analysis, the device can adapt to the field detection environment, can stably and remotely monitor rainfall capacity and water surface evaporation capacity, and has accurate detection results.

TABLE 3 comparison of rainfall evaporation automatic monitoring integrated device and manual detection results

In a word, the success rate of switching the running state of the device is 100%, the mean time ranges of the delays for starting to switch the states with rain and without rain are respectively 8.3-14.7 s and 11-23 s, and the range of the extreme differences of the state switching delays is respectively 1-4 s and 2-5 s, so that the device meets the requirements of the industry standard of automatic rain shielding monitor technical requirements and detection methods on the automatic rain shielding device for shielding rain within 60s and eliminating rain within 5min, and the device is proved to run reliably; the rainfall and water surface evaporation simulation test results show that in the 33 times of simulated rainfall and water surface evaporation test processes, the detection errors of the rainfall and the water surface evaporation are respectively-0.73-0.71%, -2.50-2.00%, the standard deviation ranges are respectively 0.06-0.38 mm and 0.01-0.09 mm, the requirements of national standards of rainfall observation instruments and water surface evaporators on the detection errors of the rainfall and the water surface evaporation are not more than +/-3%, and the detection results of the device are more accurate and stable; the field test results of rainfall and water surface evaporation show that the rainfall detected by the device is higher than the manual detection result, and the relative error range is 1.42-11.11%; the water surface evaporation amount detected by the device is lower than a manual detection result, and the relative error range is-5.20 to-1.34 percent, which shows that the device can adapt to a field detection environment, can stably and remotely monitor rainfall amount and water surface evaporation amount, and has accurate detection result.