Sine function dynamic water pressure generation method based on electric control valve

Abstract

The invention discloses a sine function dynamic water pressure generation method based on an electric control valve. The sine function dynamic water pressure generation method comprises the steps that S1, generation parameters of target dynamic water pressure are set; s2, the maximum value and the minimum value of the downstream pressure are calculated based on the generated parameters, the corresponding valve body opening value is calculated according to the downstream pressure, the valve body opening is adjusted to the corresponding opening, and dynamic water pressure is generated; s3, the dynamic water pressure is processed, a plurality of discrete intervals are obtained, and the downstream pressure value, the electric pulse value and the valve opening and closing rate of each time node in each discrete interval are calculated; s4, a stepping motor is controlled to conduct valve opening and closing adjustment, and whether the device operation time exceeds the dynamic water pressure generation period or not is judged; and S5, if the dynamic water pressure generation period is not exceeded, repeating the steps S3-S4, and if the dynamic water pressure generation period is equal to or exceeded, returning to S1 to start the next period. The electric adjusting valve is adopted as an adjusting mechanism, and automatic generation of dynamic water pressure is achieved through the opening and closing speed of the valve.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural irrigation, and in particular to a method for generating sinusoidal function dynamic water pressure based on an electric regulating valve. Background Art

[0002] At present, drip irrigation uses surface water with a high sand content as the water source, which can effectively alleviate the problem of water shortage. However, since the emitters used in the drip irrigation system are relatively precise and tiny, the use of sand-containing water is accompanied by blockage, which seriously affects the uniformity of drip irrigation and causes crops to face the problem of reduced yields.

[0003] More and more studies have shown that the dynamic water pressure irrigation mode has an excellent effect on dripper anti-clogging. At present, the main ways to achieve dynamic water pressure are to install a pulse generator or control the frequency of a variable frequency water pump. Although it has good application effects and is widely used in agricultural irrigation, the existing dynamic water pressure generation technology mainly relies on external equipment, which greatly increases the cost of irrigation, and the dynamic water pressure generation process fluctuates greatly and is unstable. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a sinusoidal function dynamic water pressure generation method based on an electric regulating valve to solve the problems of high cost and instability of the prior art.

[0005] On the one hand, to achieve the above-mentioned purpose, the present invention provides a method for generating a sinusoidal function dynamic water pressure based on an electric regulating valve, comprising:

[0006] S1. Setting generation parameters of target dynamic water pressure;

[0007] S2, calculating the maximum and minimum values ​​of the pressure after the valve based on the generated parameters, and calculating the corresponding valve body opening value according to the pressure after the valve, adjusting the valve body opening to the corresponding opening, and generating dynamic water pressure;

[0008] S3, processing the dynamic water pressure to obtain a number of discrete intervals, and calculating the valve back pressure value, electric pulse value and valve opening and closing rate at each time node in each discrete interval;

[0009] S4, controlling the stepper motor to adjust the valve opening and closing according to the post-valve pressure value, the electric pulse value and the valve opening and closing rate, and judging whether the device operation time exceeds the dynamic water pressure generation cycle in the generation parameters;

[0010] S5. If the dynamic water pressure generation cycle is not exceeded, S3-S4 are repeated. If the dynamic water pressure generation cycle is equal to or exceeded, return to S1 to start the next cycle.

[0011] Preferably, the method for calculating the maximum and minimum values ​​of the post-valve pressure is:

[0012] A=H max -H min (1)

[0013]

[0014] Where A is the dynamic water pressure amplitude, m; H max is the maximum valve back pressure value, m; H min is the minimum pressure after the valve, m; is the average pressure after the valve, m;

[0015] By combining equation (1) and equation (2), the maximum and minimum values ​​of the pressure after the valve are calculated.

[0016] Preferably, the method for calculating the corresponding valve body opening value according to the post-valve pressure is:

[0017] l re =a1H 2 +b1H+c1(3)

[0018] In the formula, l re is the valve body opening value; H is the pressure after the valve, m; a1, b1, c1 are the opening calculation parameters respectively.

[0019] Preferably, the method for calculating the post-valve pressure value at each time node in each discrete interval is:

[0020]

[0021] In the formula, H i is the pressure after the valve at a certain moment, m; t i is the device operation time up to a certain moment, s; ω is the dynamic water pressure generation period, s; ​​A is the dynamic water pressure generation amplitude; H min It is the minimum downstream pressure setting value.

[0022] Preferably, the method for calculating the electrical pulse value at each time node in each discrete interval is:

[0023] K=a2l re -b2 (5)

[0024] Where K is the electric pulse value; a2 and b2 are the electric pulse calculation parameters, l re is the valve body opening value.

[0025] Preferably, the method for calculating the valve opening and closing rate at each time node in each discrete interval is:

[0026]

[0027] Where Vi t i The valve opening and closing rate at the moment, pulse / s; K i t i The valve electrical pulse at the moment, pulse; K i+1 t i+1 The valve electrical pulse at that moment, pulse.

[0028] Preferably, the method for judging whether the operation time of the device exceeds the dynamic water pressure generation period in the generation parameter is:

[0029] Taylor expansion is performed on the formula for calculating the valve opening and closing rate at each time node in each discrete interval, and the trigonometric function value is calculated for the time node to obtain the calculation result. Based on the calculation result, it is determined whether the operation time of the device exceeds the dynamic water pressure generation cycle in the generation parameter.

[0030] Preferably, the method of Taylor expansion of the formula for calculating the valve opening and closing rate at each time node in each discrete interval is:

[0031]

[0032] Where t′ is the period calculation coefficient, and σ is the high-order infinitesimal in the Taylor expansion.

[0033] On the other hand, in order to achieve the above-mentioned purpose, the present invention also provides a sine function dynamic water pressure generating device based on an electric regulating valve, comprising:

[0034] A water reservoir, an electric ball valve, a water pump, a PLC controller, a control terminal, a flow meter, an angle flat valve and a pressure sensor, wherein the water pump is connected to the water reservoir, the flow meter is connected to the water pump, a first pressure sensor is connected between the angle flat valve and the flow meter, a second pressure sensor is connected between the angle flat valve and the electric ball valve, the other end of the electric ball valve is connected to the water reservoir, the PLC controller controls the opening adjustment of the angle flat valve and monitors the operating data of each device, and the control terminal is connected to the PLC controller.

[0035] Compared with the prior art, the present invention has the following advantages and technical effects:

[0036] The present invention provides a method for generating sinusoidal function dynamic water pressure based on an electric regulating valve. The method sets the maximum valve rear pressure and the minimum valve rear pressure according to user needs, calculates the required amplitude and vibration period, and controls the opening and closing rate of the stepper motor of the electric regulating valve according to the relationship between the valve rear pressure and the regulation cycle time, thereby generating dynamic water pressure.

[0037] The present invention can not only be used as a new method for generating dynamic water pressure, but also solves the problems of high cost and unstable operation of generating dynamic water pressure in existing agricultural irrigation. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0039] Figure 1 This is a flow chart of a method for generating a sinusoidal function dynamic water pressure based on an electric regulating valve according to an embodiment of the present invention;

[0040] Figure 2 It is a schematic diagram of a sinusoidal function dynamic water pressure generating device according to an embodiment of the present invention;

[0041] Figure 3 The following are curves showing the relationship between the pressure after the valve and time under different periods and amplitudes of the embodiment of the present invention, wherein (a) is a 36s sine function dynamic water pressure effect diagram, (b) is a 48s sine function dynamic water pressure effect diagram, and (c) is a 60s sine function dynamic water pressure effect diagram;

[0042] Figure 4 Graphs showing the relationship between flow and time at different periods and amplitudes of the embodiments of the present invention, wherein (a) is a graph showing the flow rate changing over time at 36 s, (b) is a graph showing the flow rate changing over time at 48 s, and (c) is a graph showing the flow rate changing over time at 60 s;

[0043] Among them, 1. Water reservoir; 2. Electric ball valve; 3. Water pump; 4. PLC controller; 5. Control terminal; 6. Flow meter; 7. Angle flat valve; 8. Pressure sensor. DETAILED DESCRIPTION

[0044] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0045] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0046] The present invention proposes a method for generating a sinusoidal function dynamic water pressure based on an electric regulating valve. Figure 1 ,include:

[0047] S1. Setting generation parameters of target dynamic water pressure;

[0048] S2, calculating the maximum and minimum values ​​of the pressure after the valve based on the generated parameters, and calculating the corresponding valve body opening value according to the pressure after the valve, adjusting the valve body opening to the corresponding opening, and generating dynamic water pressure;

[0049] S3, processing the dynamic water pressure to obtain a number of discrete intervals, and calculating the valve back pressure value, electric pulse value and valve opening and closing rate at each time node in each discrete interval;

[0050] S4, controlling the stepper motor to adjust the valve opening and closing according to the post-valve pressure value, the electric pulse value and the valve opening and closing rate, and judging whether the device operation time exceeds the dynamic water pressure generation cycle in the generation parameters;

[0051] S5. If the dynamic water pressure generation cycle is not exceeded, S3-S4 are repeated. If the dynamic water pressure generation cycle is equal to or exceeded, return to S1 to start the next cycle.

[0052] The present embodiment provides a method for generating sinusoidal function dynamic water pressure based on an electric control valve. The method sets the maximum valve post-pressure and the minimum valve post-pressure according to user needs, calculates the required amplitude and vibration period, and controls the opening and closing rate of the stepper motor of the electric control valve according to the relationship between the valve post-pressure and the adjustment cycle time, thereby generating dynamic water pressure.

[0053] Furthermore, the generation parameters of the target dynamic water pressure include generation parameters such as the amplitude, period and average pressure of the target dynamic water pressure.

[0054] Furthermore, the method for calculating the maximum and minimum values ​​of the post-valve pressure is:

[0055] A=H max -H min (1)

[0056]

[0057] Where A is the dynamic water pressure amplitude, m; H max is the maximum valve back pressure value, m; H min is the minimum pressure after the valve, m; is the average pressure after the valve, m;

[0058] Combine equation (1) and equation (2) to calculate the maximum and minimum pressure after the valve.

[0059] Specifically, the maximum and minimum values ​​of the valve rear pressure are calculated according to the generated parameters, and the corresponding opening value is calculated according to the minimum valve rear pressure setting value, the valve body opening is adjusted to the opening corresponding to the minimum valve rear pressure setting value, and dynamic water pressure is started to be generated at the same time.

[0060] Furthermore, the method for calculating the corresponding valve body opening value according to the pressure after the valve is:

[0061] l re =a1H 2 +b1H+c1(3)

[0062] In the formula, l re is the valve body opening value; H is the pressure value after the valve; a1, b1, c1 are the opening calculation parameters respectively.

[0063] Furthermore, the required dynamic water pressure is discretized into images to obtain several discrete intervals, and the post-valve pressure value, electric pulse value and valve opening and closing rate at each time node in each discrete interval are calculated.

[0064] Specifically, the method for calculating the post-valve pressure value at each time node in each discrete interval is:

[0065]

[0066] In the formula, H i is the pressure after the valve at a certain moment; t i is the device operation time up to a certain moment, s; ω is the dynamic water pressure generation cycle, s.

[0067] The method for calculating the electrical pulse value at each time node in each discrete interval is:

[0068] K=a2l re -b2 (5)

[0069] Where K is the electric pulse value; a2 and b2 are the electric pulse calculation parameters, l re is the valve body opening value.

[0070] The method for calculating the valve opening and closing rate at each time node in each discrete interval is:

[0071]

[0072] Where V i t i The valve opening and closing rate at the moment, pulse / s; K i t i The valve electrical pulse at the moment, pulse; K i+1 t i+1 The valve electrical pulse at that moment, pulse.

[0073] Furthermore, the method for determining whether the device operation time exceeds the dynamic water pressure generation period in the generation parameters is:

[0074] Taylor expansion is performed on the formula for calculating the valve opening and closing rate at each time node in each discrete interval, and the trigonometric function value is obtained for the time node to obtain the calculation result. Based on the calculation result, it is judged whether the device operation time exceeds the dynamic water pressure generation cycle in the generation parameter. The relationship between the current total operation time and the generation cycle is judged every 3 seconds, and the PLC automatically determines it.

[0075] Specifically, it is determined whether the device operation time exceeds the dynamic water pressure generation cycle. If not, steps S3-S4 are repeated; if just equal to or exceeded, a cycle of dynamic water pressure has been completed, and the next cycle starts from S1.

[0076] Since the calculation of the pressure after the valve at each time node requires the trigonometric function value of the time node, but because the device controls the stepper motor through the PLC, and the PLC cannot directly calculate the pressure after the valve at each time point in the discrete interval, the Taylor expansion of formula (6) is performed, and the expression is:

[0077]

[0078] Where t′ is the period calculation coefficient; σ is the high-order infinitesimal in the Taylor expansion and can be ignored.

[0079] This embodiment also provides a sine function dynamic water pressure generating device based on an electric regulating valve, such as Figure 2 , used to implement a sinusoidal function dynamic water pressure generation method based on an electric regulating valve, comprising:

[0080] Water reservoir 1, electric ball valve 2, water pump 3, PLC controller 4, control terminal 5, flow meter 6, angle flat valve 7 and pressure sensor 8, wherein the water pump 3 is connected to the water reservoir 1, the flow meter 6 is connected to the water pump 3, a first pressure sensor is connected between the angle flat valve 7 and the flow meter 6, a second pressure sensor is connected between the angle flat valve 7 and the electric ball valve 2, the other end of the electric ball valve 2 is connected to the water reservoir 1, the PLC controller 4 controls the opening adjustment control of the angle flat valve 7 and monitors the operating data of each device, and the control terminal 5 is connected to the PLC controller 4.

[0081] Furthermore, the water pump 3 is used to provide the required water pressure, the flow meter 6 is used to monitor the pipeline flow, the angle flat valve 7 is the action mechanism of the normal water pressure, and the electric ball valve 2 is used as the user simulation end.

[0082] In order to more clearly express the technical solution of the present invention, the following specific embodiments are provided to introduce the solution:

[0083] The present embodiments are all carried out under a pre-valve pressure of 0.1 MPa. According to user needs, three amplitude levels of 5m, 4m and 3m, three periods of 36s, 48s and 60s, and corresponding three average pressure levels of 2.5m, 2m and 1.5m are set.

[0084] According to the set dynamic water pressure generation parameters, the maximum and minimum pressures after the valve are calculated respectively. The relevant calculation formula is:

[0085] A=H max -H min (9)

[0086]

[0087] Where A is the dynamic water pressure amplitude, m; H max is the maximum valve back pressure value, m; H min is the minimum pressure after the valve, m; is the average pressure after the valve, m.

[0088] By combining equation (9) and equation (10), the maximum and minimum values ​​of the pressure after the valve can be calculated; that is, the three pressure ranges after the valve are 0-0.05MPa, 0.01-0.05MPa and 0.02-0.05MPa.

[0089] According to user needs, calculate the opening value corresponding to the minimum valve back pressure respectively. The opening calculation expression is:

[0090] l re =0.0248H 2 +0.0083H+0.1709(11)

[0091] In the formula, l re is the valve opening, %; H2 is the pressure after the valve, m.

[0092] It is calculated that when the pressure behind the valve is 0MPa, the opening is 0%, when the pressure behind the valve is 0.01MPa, the opening is 20%, and when the pressure behind the valve is 0.02MPa, the opening is 29%. The valve body opening is adjusted to the opening corresponding to the minimum valve back pressure setting value to start generating dynamic water pressure.

[0093] In order to ensure that the angle flat valve can operate at a certain opening and closing rate within a certain period of time, the required dynamic water pressure is discretized into images to obtain several discrete intervals. Then, the valve back pressure value, valve electrical pulse and valve opening and closing rate of each discrete interval at each time node in each discrete interval are calculated.

[0094] Furthermore, the calculation formula of the post-valve pressure value at each time node is:

[0095]

[0096] In the formula, H i is the pressure after the valve at a certain moment, m; t i is the device operation time up to a certain moment, s; ω is the dynamic water pressure generation cycle, s.

[0097] Furthermore, the calculation formula for the pressure after the valve under different period and amplitude conditions is obtained by the above method and is shown in Table 1.

[0098] Table 1

[0099]

[0100] Furthermore, since the calculation of the valve back pressure at each time node requires the trigonometric function value of the time node, but because the device controls the stepper motor through the PLC, and the PLC cannot directly calculate the valve back pressure at each time point in the discrete interval, the sine function part in equation (12) is Taylor expanded, and the expression obtained is:

[0101]

[0102] The calculation formula of the electric pulse at each time node is:

[0103] K=256l re (15)

[0104] Where K is the valve electrical pulse.

[0105] The calculation formula for the valve opening and closing rate at each time node is:

[0106]

[0107] Where V i t i The valve opening and closing rate at the moment, pulse / s; K i t i The valve electrical pulse at the moment, pulse; K i+1 t i+1 The valve electrical pulse at the moment, pulse;

[0108] Furthermore, the post-valve pressure value, valve electrical pulse and valve opening and closing rate at each time node calculated according to different user requirements are recorded in the following Tables 2(a), 2(b) and 2(c).

[0109] Table 2(a)

[0110]

[0111] Table 2(b)

[0112]

[0113]

[0114] Table 2(c)

[0115]

[0116] The calculated and actual values ​​of the valve back pressure under different cycles and amplitudes are shown in Figure 3 (a)-(c), calculated flow values ​​and actual flow values ​​are shown in Figure 4 (a)-(c).

[0117] The present invention can not only be used as a new method for generating dynamic water pressure, but also solves the problems of high cost and unstable operation of generating dynamic water pressure in existing agricultural irrigation.

[0118] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for generating sinusoidal function dynamic water pressure based on an electric regulating valve, characterized in that: include: S1. Setting generation parameters of target dynamic water pressure; S2, calculating the maximum and minimum values ​​of the pressure after the valve based on the generated parameters, and calculating the corresponding valve body opening value according to the pressure after the valve, adjusting the valve body opening to the corresponding opening, and generating dynamic water pressure; S3, processing the dynamic water pressure to obtain a number of discrete intervals, and calculating the valve back pressure value, electric pulse value and valve opening and closing rate at each time node in each discrete interval; S4, controlling the stepper motor to adjust the valve opening and closing according to the post-valve pressure value, the electric pulse value and the valve opening and closing rate, and judging whether the device operation time exceeds the dynamic water pressure generation cycle in the generation parameters; S5. If the dynamic water pressure generation cycle is not exceeded, S3-S4 are repeated. If the dynamic water pressure generation cycle is equal to or exceeded, return to S1 to start the next cycle.

2. The method for generating sinusoidal function dynamic water pressure based on an electric regulating valve according to claim 1, characterized in that: The method for calculating the maximum and minimum values ​​of the pressure after the valve is: A=H max -H min (1) Where A is the dynamic water pressure amplitude, m; H max is the maximum valve back pressure value, m; H min is the minimum pressure after the valve, m; is the average pressure after the valve, m; By combining equation (1) and equation (2), the maximum and minimum values ​​of the pressure after the valve are calculated.

3. The method for generating sinusoidal function dynamic water pressure based on an electric regulating valve according to claim 1, characterized in that: The method for calculating the corresponding valve body opening value according to the valve rear pressure is: l re =a1H 2 +b1H+c1(3) In the formula, l re is the valve body opening value; H is the pressure after the valve, m; a1, b1, c1 are the opening calculation parameters respectively.

4. The method for generating sinusoidal function dynamic water pressure based on an electric regulating valve according to claim 1, characterized in that: The method for calculating the valve back pressure value at each time node in each discrete interval is: In the formula, H i is the pressure after the valve at a certain moment, m; t i is the device operation time up to a certain moment, s; ω is the dynamic water pressure generation period, s; ​​A is the dynamic water pressure generation amplitude; H min It is the minimum downstream pressure setting value.

5. The method for generating sinusoidal function dynamic water pressure based on an electric regulating valve according to claim 4, characterized in that: The method for calculating the electrical pulse value at each time node in each discrete interval is: <h2 style=";text-align:left;direction:ltr">K=a2l<h2 style=";text-align:left;direction:ltr"> re <h2 style=";text-align:left;direction:ltr"> -b2 (5) Where K is the electric pulse value; a2 and b2 are the electric pulse calculation parameters, l re is the valve body opening value.

6. The method for generating sinusoidal function dynamic water pressure based on an electric regulating valve according to claim 5, characterized in that: The method for calculating the valve opening and closing rate at each time node in each discrete interval is: Where V i t i The valve opening and closing rate at the moment, pulse / s; K i t i The valve electrical pulse at the moment, pulse; K i+1 t i+1 The valve electrical pulse at that moment, pulse.

7. The method for generating sinusoidal function dynamic water pressure based on an electric regulating valve according to claim 6, characterized in that: The method for judging whether the operation time of the device exceeds the dynamic water pressure generation period in the generation parameter is: Taylor expansion is performed on the formula for calculating the valve opening and closing rate at each time node in each discrete interval, and the trigonometric function value is calculated for the time node to obtain the calculation result. Based on the calculation result, it is determined whether the operation time of the device exceeds the dynamic water pressure generation cycle in the generation parameter.

8. The method for generating sinusoidal function dynamic water pressure based on an electric regulating valve according to claim 7, characterized in that: The method of Taylor expansion of the formula for calculating the valve opening and closing rate at each time node in each discrete interval is: Where t′ is the period calculation coefficient, and σ is the high-order infinitesimal in the Taylor expansion.

9. A sine function dynamic water pressure generating device based on an electric regulating valve, used to implement the sine function dynamic water pressure generating method based on an electric regulating valve according to any one of claims 1 to 8, characterized in that: include: A water reservoir (1), an electric ball valve (2), a water pump (3), a PLC controller (4), a control terminal (5), a flow meter (6), an angle plate valve (7) and a pressure sensor (8), wherein the water pump (3) is connected to the water reservoir (1), the flow meter (6) is connected to the water pump (3), a first pressure sensor is connected between the angle plate valve (7) and the flow meter (6), a second pressure sensor is connected between the angle plate valve (7) and the electric ball valve (2), the other end of the electric ball valve (2) is connected to the water reservoir (1), the PLC controller (4) controls the opening adjustment of the angle plate valve (7) and monitors the operating data of each device, and the control terminal (5) is connected to the PLC controller (4).

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