阅读说明：本技术 一种变量喷雾控制方法、装置及系统 (Variable spray control method, device and system ) 是由 秦五昌 孟志军 张光强 尹彦鑫 梅鹤波 郭树霞 罗长海 于 2021-06-04 设计创作，主要内容包括：本发明提供一种变量喷雾控制方法、装置及系统,该方法包括：根据喷雾喷头实时的压力,采用前馈补偿的压力闭环模糊控制法,调节喷雾喷头的实时流量,直至喷雾喷头的当前压力与目标压力之间的误差小于第一误差阈值；采用实时自适应的喷头压力与喷头流量控制法,继续调节喷雾喷头的实时流量；获取实时顷喷量,采用基于实时顷喷量反馈的顷喷量控制法,继续调节喷雾喷头的实时流量,直至调整后的实时顷喷量与目标顷喷量之间的误差小于第二误差阈值。本发明提供的变量喷雾控制方法、装置及系统,采用双闭环双模糊自适应的变量喷雾控制方法,能克服解决变量喷洒作业过程中喷头不同压力性能差异等对喷洒精度的影响,有效地提高了变量喷洒控制装置的精度。(The invention provides a variable spray control method, a device and a system, wherein the method comprises the following steps: adjusting the real-time flow of the spray nozzle by adopting a pressure closed-loop fuzzy control method of feedforward compensation according to the real-time pressure of the spray nozzle until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold; continuously adjusting the real-time flow of the spray nozzle by adopting a real-time self-adaptive nozzle pressure and nozzle flow control method; and (3) acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is less than a second error threshold. The variable spray control method, the variable spray control device and the variable spray control system provided by the invention adopt the double closed-loop double fuzzy self-adaptive variable spray control method, can overcome the influence on the spraying precision caused by different pressure performance differences of the spray head in the variable spraying operation process, and effectively improve the precision of the variable spray control device.)

1. A variable spray control method, comprising:

step S1, acquiring the real-time pressure and flow of the spray nozzle;

step S2, according to the pressure, adopting a pressure closed-loop fuzzy control method of feedforward compensation to adjust the real-time flow of the spray nozzle until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

step S3, adopting a real-time self-adaptive spray head pressure and flow control method to continuously adjust the real-time flow of the spray head;

step S4, acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold value;

and step S5, iteratively executing the steps S1 to S4 until the spraying task is completed.

2. The variable spray control method according to claim 1, wherein the step S2 specifically comprises:

based on a gradient descent method, a hysteresis quantity comparison table is constructed by measuring the pressure control hysteresis of various types of spray nozzles;

designing a fuzzy controller according to the hysteresis quantity comparison table;

inputting the current pressure and the target pressure to the fuzzy controller to realize hierarchical control based on real-time pressure and target pressure.

3. The variable spray control method according to claim 2, wherein the hierarchical control specifically comprises:

step S21, determining a pressure error between the current pressure and the target pressure;

step S22, predicting the pressure lag and the duty ratio of pulse width modulation according to the pressure error;

a step S23 of setting a sum of the pressure hysteresis amount and a target pressure as an actual target pressure;

step S24, adjusting the real-time flow of the spray nozzle by adopting a pulse width modulation method according to the duty ratio and the actual target pressure;

and step S25, iteratively executing the steps S21 to S24 until the error between the current pressure of the spray nozzle and the target pressure is smaller than a first error threshold.

4. The variable spray control method according to claim 1, wherein the step S3 specifically comprises:

acquiring a spray head correction coefficient according to the pressure, the flow, the standard pressure range and the standard flow corresponding to the standard spray head and the standard pressure range;

and continuously adjusting the real-time flow of the spray nozzle according to the nozzle correction coefficient.

5. The variable spray control method according to claim 1, wherein the step S4 specifically comprises:

s41, according to the hectare spray error between the real-time hectare spray and the target hectare spray;

s42, adjusting the real-time spraying amount in the spraying process by adjusting the real-time flow of the spraying nozzle by adopting a successive approximation method;

s43, determining the time unit of the successive approximation method according to the hectare spraying amount error and the current pressure of the spraying nozzle;

s44, the steps S41 to S43 are executed iteratively until the error between the adjusted real-time spraying amount and the target spraying amount is less than a second error threshold.

6. The variable spray control method according to claim 5, wherein the calculation formula of the time unit of the successive approximation method is:

wherein Δ t is the time unit, k is the correction factor for the time unit, f is the current pressure, and e is the hectare spray error.

7. A variable spray control device, comprising:

the data acquisition unit is used for acquiring the real-time pressure and flow of the spray nozzle;

the first control module is used for adjusting the real-time flow of the spray nozzle by adopting a pressure closed-loop fuzzy control method of feedforward compensation according to the pressure until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

the second control module is used for continuously adjusting the real-time flow of the spray nozzle by adopting a real-time self-adaptive nozzle pressure and nozzle flow control method;

the third control module is used for acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold;

and the iteration control module is used for controlling the iteration operation of the data acquisition unit, the first control module, the second control module and the third control module in an iteration mode until a spraying task is finished.

8. A variable spray control system, comprising: the spraying device comprises a spraying nozzle, a controller, and a variable control valve, a flow sensor and a pressure sensor which are connected with the controller;

the flow sensor and the pressure sensor are both arranged in a pipeline connected with the variable control valve and the spray nozzle;

the flow sensor is used for acquiring the real-time flow of the spray nozzle in real time; the pressure sensor is used for acquiring the real-time pressure of the spray nozzle in real time;

the controller is configured to perform the steps of:

step S2, according to the pressure, adopting a pressure closed-loop fuzzy control method of feedforward compensation to adjust the real-time flow of the spray nozzle until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

step S3, adopting a real-time self-adaptive spray head pressure and flow control method to continuously adjust the real-time flow of the spray head;

step S4, acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold value;

and step S5, iteratively executing the steps S2 to S4 until the spraying task is completed.

9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the variable spray control method steps of any of claims 1 to 6 when executing the computer program.

10. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the computer program when executed by a processor implements the variable spray control method steps of any of claims 1 to 6.

Technical Field

The invention relates to the technical field of intelligent sprinkling irrigation, in particular to a variable spraying control method, device and system.

Background

The liquid medicine amount of agricultural spraying operation is mainly determined by spraying pressure, the relation of flow pressure of different types of spray heads is limited in national standard, and the flow per minute is obtained by multiplying the type of the spray head by 0.4 liter under the condition of 0.3 Mpa.

The traditional spraying pesticide application and liquid fertilizer spraying machines are easy to cause uneven spraying, and the solution is to increase the application amount, not only cause low utilization rate, but also cause environmental pollution. In recent years, variable based on speed sprays, the constant voltage sprays, unmanned aerial vehicle sprays and develops rapidly, mainly is based on the pressure control of shower nozzle characteristic, because long-time spraying back shower nozzle is easy to wear and is blockked up, causes the flow and the pressure characteristic of shower nozzle to change, leads to the liquid medicine to spray the volume degree of accuracy and reduce. At present, a great amount of traditional plant protection machines are kept in a long service life, and after-installed variable spraying equipment is not adaptive and complex in calibration and cannot adapt to the current situations of dirty water, non-standard spray heads and performance difference of the spray heads.

The aim of current variable spray operation adjustment is to adjust the flow rate of the spray head, mainly by adjusting the pressure. For example, in a variable spraying control system of the topotecan, only a pressure sensor is used, spraying amount control is carried out by controlling pressure, and the relation between the spraying amount and the pressure needs to be calibrated before operation. And the PWM control technology is adopted, the rotating speed of the liquid pump or the opening degree of the electromagnetic valve is adjusted in real time, and the pressure is adjusted in real time through pressure feedback. In addition, the prior art also improves the accuracy of pressure control by not calibrating (adaptive) the operation. The other method is to feed back through a flow sensor to adjust the rotating speed of the liquid pump or the opening degree of the electromagnetic valve in real time.

The pressure is adjusted in real time through pressure feedback, and an adjusting mode without calibration (namely self-adaption) operation is adopted, so that errors exist in spray amount (hectare spray amount) per hectare due to the fact that errors exist in spray head correction and pressure control all the time; another kind of spraying control based on flow sensor needs high accuracy flow sensor, and the turbine flowmeter who uses at present has big to the calculation error of instantaneous flow, can feed back after need accumulate certain time flow smoothness, and the control cycle is long, and turbine flowmeter error under the turbulent flow is very big.

Disclosure of Invention

Aiming at the problems in the prior art, the embodiment of the invention provides a variable spray control method, device and system.

In a first aspect, the present invention provides a variable spray control method, comprising the steps of:

step S1, acquiring the real-time pressure and flow of the spray nozzle;

step S2, according to the pressure, adopting a pressure closed-loop fuzzy control method of feedforward compensation to adjust the real-time flow of the spray nozzle until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

step S3, adopting a real-time self-adaptive spray head pressure and flow control method to continuously adjust the real-time flow of the spray head;

step S4, acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold value;

and step S5, iteratively executing the steps S1 to S4 until the spraying task is completed.

In an embodiment, the step S2 specifically includes:

based on a gradient descent method, a hysteresis quantity comparison table is constructed by measuring the pressure control hysteresis of various types of spray nozzles;

designing a fuzzy controller according to the hysteresis quantity comparison table;

inputting the current pressure and the target pressure to the fuzzy controller to realize hierarchical control based on real-time pressure and target pressure.

In one embodiment, the hierarchical control specifically includes:

step S21, determining a pressure error between the current pressure and the target pressure;

step S22, predicting the pressure lag and the duty ratio of pulse width modulation according to the pressure error;

a step S23 of setting a sum of the pressure hysteresis amount and a target pressure as an actual target pressure;

step S24, adjusting the real-time flow of the spray nozzle by adopting a pulse width modulation method according to the duty ratio and the actual target pressure;

and step S25, iteratively executing the steps S21 to S24 until the error between the current pressure of the spray nozzle and the target pressure is smaller than a first error threshold.

In an embodiment, the step S3 specifically includes:

acquiring a spray head correction coefficient according to the pressure, the flow, the standard pressure range and the standard flow corresponding to the standard spray head and the standard pressure range;

and continuously adjusting the real-time flow of the spray nozzle according to the nozzle correction coefficient.

In an embodiment, the step S4 specifically includes:

s41, according to the hectare spray error between the real-time hectare spray and the target hectare spray;

s42, adjusting the real-time spraying amount in the spraying process by adjusting the real-time flow of the spraying nozzle by adopting a successive approximation method;

s43, determining the time unit of the successive approximation method according to the hectare spraying amount error and the current pressure of the spraying nozzle;

s44, the steps S41 to S43 are executed iteratively until the error between the adjusted real-time spraying amount and the target spraying amount is less than a second error threshold.

In one embodiment, the calculation formula of the time unit of the successive approximation method is as follows:

wherein Δ t is the time unit, k is the correction factor for the time unit, f is the current pressure, and e is the hectare spray error.

In a second aspect, the present invention provides a variable spray control device comprising:

the data acquisition unit is used for acquiring the real-time pressure and flow of the spray nozzle;

the first control module is used for adjusting the real-time flow of the spray nozzle by adopting a pressure closed-loop fuzzy control method of feedforward compensation according to the pressure until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

the second control module is used for continuously adjusting the real-time flow of the spray nozzle by adopting a real-time self-adaptive nozzle pressure and nozzle flow control method;

the third control module is used for acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold;

and the iteration control module is used for controlling the iteration operation of the data acquisition unit, the first control module, the second control module and the third control module in an iteration mode until a spraying task is finished.

In a third aspect, the present invention provides a variable spray control system comprising: the spraying device comprises a spraying nozzle, a controller, and a variable control valve, a flow sensor and a pressure sensor which are connected with the controller;

the flow sensor and the pressure sensor are both arranged in a pipeline connected with the variable control valve and the spray nozzle;

the flow sensor is used for acquiring the real-time flow of the spray nozzle in real time; the pressure sensor is used for acquiring the real-time pressure of the spray nozzle in real time;

the controller is configured to perform the steps of:

step S2, according to the pressure, adopting a pressure closed-loop fuzzy control method of feedforward compensation to adjust the real-time flow of the spray nozzle until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

step S3, adopting a real-time self-adaptive spray head pressure and flow control method to continuously adjust the real-time flow of the spray head;

step S4, acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold value;

and step S5, iteratively executing the steps S2 to S4 until the spraying task is completed.

In a fourth aspect, the present invention provides an electronic device, comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor executes the program to implement the steps of the variable spray control method according to any one of the above aspects.

In a fifth aspect, the present invention also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the variable spray control method as described in any one of the above.

The variable spray control method, the variable spray control device and the variable spray control system provided by the invention adopt the double closed-loop double fuzzy self-adaptive variable spray control method, can overcome the influence on the spraying precision caused by different pressure performance differences of the spray head in the variable spraying operation process, and effectively improve the precision of the variable spray control device.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a schematic flow diagram of a variable spray control method provided by the present invention;

FIG. 2 is a schematic flow diagram of another variable spray control method provided by the present invention;

FIG. 3 is a schematic structural diagram of a variable spray control device provided by the present invention;

FIG. 4 is a schematic diagram of a variable spray control system according to the present invention;

FIG. 5 is a schematic diagram of the variation of the driving speed and the spraying amount of the crane with time according to the present invention;

fig. 6 is a schematic structural diagram of an electronic device provided in the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that in the description of the embodiments of the present invention, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element. The terms "upper", "lower", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The variable spray control method and apparatus provided by the embodiments of the present invention will be described below with reference to fig. 1 to 6.

Fig. 1 is a schematic flow chart of a variable spray control method provided by the present invention, as shown in fig. 1, including but not limited to the following steps:

step S1, acquiring the real-time pressure and flow of the spray nozzle;

the variable spray control method provided by the invention realizes variable spray control mainly by adjusting the opening of a variable control valve (also called a proportional valve). The flow sensor and the pressure sensor are arranged on a pipeline connected with the variable control valve and the spray nozzle, so that the pressure and the flow of the spray nozzle can be acquired in real time.

The collected pressure and flow are uploaded to a flow controller in real time.

Step S2, according to the pressure, adopting a pressure closed-loop fuzzy control method of feedforward compensation to adjust the real-time flow of the spray nozzle until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

fig. 2 is a schematic flow chart of another variable spray control method provided by the present invention, and as shown in fig. 2, the present invention is a method for implementing variable spray control by using dual closed-loop dual fuzzy adaptive control, wherein the method mainly comprises two closed-loop control parts and an adaptive control part, and in step S2, the control part of the first closed-loop is mainly implemented.

The first closed loop is mainly a closed loop of pressure closed loop fuzzy control adopting feedforward compensation.

Due to the characteristics of large hysteresis and nonlinearity of pressure or flow control, the invention adjusts the control speed of the proportional valve by the conventional Pulse Width Modulation (PWM) technology through pressure closed loop fuzzy control, and can effectively reduce the hysteresis quantity.

In addition, the invention further eliminates the influence of the hysteresis quantity by adopting a feedforward compensation method. The feed forward compensation amount may be experimentally predetermined and is previously considered in the control of the actual proportional valve so that the adjusted pressure maximally coincides with the target pressure.

The first error threshold may be 0 or infinitesimal, or may be preset according to the requirement of implementing the control accuracy. In the case where the error threshold is set slightly larger, the control accuracy can be sacrificed appropriately to accelerate the speed of adjustment.

Step S3, adopting a real-time self-adaptive spray head pressure and flow control method to continuously adjust the real-time flow of the spray head;

step S3 mainly executes an adaptive control section.

After the matching between the current pressure and the target pressure is realized in step S2, the real-time flow of the spray nozzle is corrected and adjusted by fully considering the influences caused by the nozzle blockage and abrasion, the different types of the nozzle, the pipeline deposition and other factors, so that the flow of the spray nozzle can be adaptively adjusted, thereby precisely controlling the real-time flow of the spray nozzle, and enabling the real-time flow of the spray nozzle to be close to the flow when the blockage or abrasion condition is normal or to the flow of the nozzle of the standard type.

Step S4, acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold value;

step S4 is to perform a closed-loop-one control part, which includes a spraying amount control method using real-time spraying amount feedback, and adjust the real-time flow rate of the spraying nozzle according to the current flow rate detected by the flow rate sensor and the current vehicle speed detected by the vehicle speed sensor (e.g., vehicle-mounted GNSS receiver) so that the real-time spraying amount is as close as possible to the target spraying amount.

The second error threshold may be 0 or infinitesimal, or may be preset according to the requirement of implementing the control accuracy. In the case where the error threshold is set slightly larger, the control accuracy can be sacrificed appropriately to accelerate the speed of adjustment.

And step S5, iteratively executing the steps S1 to S4 until the spraying task is completed.

It should be noted that, the variable spray control method provided by the present invention can acquire the real-time pressure and flow rate of the spray nozzle according to the preset frequency by circularly executing the steps S1 to S4, and automatically perform the double-closed-loop and double-fuzzy adaptive control according to the acquired pressure and flow rate, so as to adjust the real-time flow rate of the spray nozzle until the whole spray task is completed, or receive the termination instruction of the operator.

The variable spray control method provided by the invention adopts a double closed-loop double fuzzy self-adaptive variable spray control method, can overcome the influence of different pressure performance differences of a spray head and the like on the spraying precision in the variable spraying operation process, and effectively improves the precision of the variable spraying control device.

Based on the content of the foregoing embodiment, as an alternative embodiment, step S2 specifically includes: based on a gradient descent method, a hysteresis quantity comparison table is constructed by measuring the pressure control hysteresis of various types of spray nozzles; designing a fuzzy controller according to the hysteresis quantity comparison table; inputting the current pressure and the target pressure to the fuzzy controller to realize hierarchical control based on real-time pressure and target pressure.

The invention provides a variable spray control method, in a control part of a closed loop I, a feedforward compensation amount can be obtained in advance through experiments by adopting a gradient descending method, and classification is carried out based on the current pressure and a target pressure so as to execute classification control, such as: different PWM values are set for different levels, and fuzzy control is carried out on the pressure through proportional and differential control.

Specifically, in the variable spray control method provided by the invention, a pressure closed-loop fuzzy control method of feedforward compensation is adopted to adjust the real-time flow of the spray nozzle, and the method comprises the following two aspects:

(1) and because the pressure or flow control has the characteristics of large hysteresis and nonlinearity, the control speed of the proportional valve is adjusted by adopting the PWM speed regulation so as to reduce the hysteresis quantity.

(2) And eliminating the influence of the hysteresis quantity by adopting a feedforward compensation method. The feedforward compensation amount is obtained through experiments. The corresponding lag is obtained by measuring the pressure control lag by adopting a gradient reduction method for various models of pesticide sprayers, so that the corresponding feedforward compensation quantity is determined according to the lag. And finally, correspondingly adjusting the PWM speed regulation parameter according to the feedforward compensation amount so as to compensate the influence of the hysteresis amount in a feedforward compensation mode.

Specifically, the hierarchical control includes, but is not limited to, the following steps:

step S21, determining a pressure error between the current pressure and the target pressure;

step S22, predicting the pressure lag and the duty ratio of pulse width modulation according to the pressure error;

a step S23 of setting a sum of the pressure hysteresis amount and a target pressure as an actual target pressure;

step S24, adjusting the real-time flow of the spray nozzle by adopting a pulse width modulation method according to the duty ratio and the actual target pressure;

and step S25, iteratively executing the steps S21 to S24 until the error between the current pressure of the spray nozzle and the target pressure is smaller than a first error threshold.

Table 1 is a comparison table of the hysteresis at the time of pressure decrease provided by the present invention, and table 2 is a comparison table of the hysteresis at the time of pressure increase provided by the present invention, specifically as follows:

TABLE 1 comparative hysteresis at pressure drop

TABLE 2 comparative table of hysteresis at pressure rise

As shown in tables 1 and 2, the "current" indicates the current pressure, the "target" indicates the target pressure, the unit of the current pressure and the target pressure is Mpa, the first column in the hysteresis prediction is the deviation range, the second column is the predicted hysteresis pressure value, and the third column is the PWM duty ratio (unit is%).

The variable spray control method provided by the invention comprises the steps of firstly adopting a gradient descent method, constructing a hysteresis quantity comparison table shown in tables 1 and 2 according to an experiment result by a measurement experiment of pressure control hysteresis of various types of spray nozzles, and then designing a fuzzy controller according to the hysteresis quantity comparison table; and finally, according to the current pressure and the target pressure, a designed fuzzy controller is adopted to realize the hierarchical control of the adjusting speed of the proportional valve.

Taking the example shown in table 1 and table 2, the specific fuzzy implementation method of the fuzzy controller comprises the following steps:

under the conditions that the current pressure is 0.79bar and the target pressure is 0.40Mpa, the hysteresis quantity can be predicted by using the table 1 firstly because the pressure drop control is performed when the 0.79bar is in the range of 0.58-0.90 Mpa and the 0.40Mpa is in the range of 0.23-0.58 Mpa.

And calculating the current pressure error to be 0.79-0.40-0.39 Mpa according to the difference between the current pressure and the target pressure. As can be seen from table 1, when the error is greater than 0.30Mpa, the predicted pressure hysteresis is 0.18Mpa, so the actual target pressure is automatically set to 0.40+0.18 Mpa, which is the sum of the pressure hysteresis and the target pressure, and table 1 shows that the PWM is to be adjusted at 41% duty ratio for the first adjustment of the proportional valve.

In the process of adjustment, the current pressure is gradually reduced, and when the pressure error is reduced to be less than or equal to 0.30Mpa and greater than 0.18Mpa, the predicted pressure lag is automatically adjusted to be 0.095Mpa according to the parameters inquired in the table 1; and the actual target pressure was set to 0.40+0.095 ═ 0.495Mpa, and the duty ratio was set to 41%. This allows the proportional valve to be readjusted.

During the continuous adjustment process, the current pressure is further reduced, and when the pressure error is reduced to be less than 0.12Mpa and more than 0.05Mpa, the controller adjusts the predicted pressure lag to be 0.05Mpa according to the parameters inquired in the table 1; the actual target pressure was set to 0.40+ 0.05-0.45 Mpa with a duty cycle set to 30%.

Further, in the case where the real-time pressure is adjusted to 0.45Mpa, which is equal to the target pressure (at this time, the first error threshold social group is 0), the adjustment is stopped.

The variable spray control method provided by the invention realizes the control of the adjusting speed of the proportional valve in a fuzzy control mode of pressure lag prediction, especially considers the influence of the lag on the adjusting result, and effectively improves the precision of variable spray control.

Based on the content of the foregoing embodiment, as an alternative embodiment, the step S3 specifically includes:

acquiring a spray head correction coefficient according to the pressure, the flow, the standard pressure range and the standard flow corresponding to the standard spray head and the standard pressure range;

and continuously adjusting the real-time flow of the spray nozzle according to the nozzle correction coefficient.

The calculation formula of the nozzle correction coefficient may be:

wherein, P_iPressure of the spray head, P_aIs a standard pressure range, F_iIs the flow rate of the spray head, F_aIs the standard flow rate of the standard spray head corresponding to the standard pressure range, K_iIs the nozzle correction factor.

In the variable spray control method provided by the present invention, the step S3 is executed by steps mainly including:

collecting the pressure and flow of a plurality of groups of spray nozzles in real time; the pressure is the real-time pressure of the spray nozzle in a standard pressure range, and the flow is the real-time flow of the spray nozzle corresponding to the real-time pressure.

According to a plurality of shower nozzle flow, judge whether the real-time flow of knowing the spraying shower nozzle is in steady state, include: and calculating the average value of the difference integrals of the plurality of flows collected in sequence, and judging to know that the real-time flow of the spray nozzle is in a stable state if the average value of the difference integrals is not greater than a preset threshold value.

And calculating the spray head correction coefficient corresponding to each group of data according to the obtained multiple groups of pressures and spray head flow rates, the standard pressure range and the standard flow rate corresponding to the standard spray head and the standard pressure range, and then calculating the average value to determine the final spray head correction coefficient.

And correcting and adjusting the real-time flow of the spray head according to the calculated spray head correction coefficient.

The variable spray control method provided by the invention can calibrate the flow of the spray nozzle in real time by adopting a real-time self-adaptive nozzle pressure and nozzle flow control method, and can correct and adjust the real-time flow of the spray nozzle under the conditions that the spray nozzle is blocked and worn, or the types of the spray nozzle are different (for example, a non-standard nozzle is used), and water consumption is not clean due to impurity deposition of a pipeline, so that the flow of the spray nozzle can be adjusted in a self-adaptive manner, thereby accurately controlling the real-time flow of the spray nozzle, and enabling the real-time flow of the spray nozzle to be close to the flow under the conditions of no blockage or wear, or to the flow of the nozzles with standard types.

Based on the content of the foregoing embodiment, as an alternative embodiment, the foregoing step S4 specifically includes, but is not limited to, the following steps:

s41, according to the hectare spray error between the real-time hectare spray and the target hectare spray;

s42, adjusting the real-time spraying amount in the spraying process by adjusting the real-time flow of the spraying nozzle by adopting a successive approximation method;

s43, determining the time unit of the successive approximation method according to the hectare spraying amount error and the current pressure of the spraying nozzle;

s44, the steps S41 to S43 are executed iteratively until the error between the adjusted real-time spraying amount and the target spraying amount is less than a second error threshold.

It should be noted that, because of the hysteresis, the final pressure of the system may reach 0.40Mpa after the hysteresis. Therefore, the adjustment can be continued by the adjustment method described in the subsequent step 4.

Specifically, after the adjustment of the loop one in step S2, if the current pressure approaches the target pressure, a pressure threshold (generally, the predicted pressure hysteresis amount obtained last time) may be set, and if the pressure error between the current pressure and the target pressure is within the threshold (i.e., smaller than the threshold), the pressure adjustment is stopped, and the closed-loop adjustment of the spraying amount described in step S4 is performed; of course, if the pressure error between the current pressure and the target pressure is still greater than the threshold, the adjustment in step S2 is continued.

In step S4, the real-time hectare spray rate can be made to approach or reach the target hectare spray rate by predicting a certain time unit and using a successive approximation method.

Optionally, the calculation formula of the time unit of the successive approximation method is as follows:

wherein Δ t is the time unit, k is the correction factor for the time unit, f is the current pressure (in mpa), and e is the hectare spray rate error.

Therein, by calculating the current hectare spray error (determined by the difference between the real-time hectare spray and the target hectare spray), the corresponding time unit is obtained by experiment based on the current pressure, the fuzzy rule as shown in table 3 is designed. .

TABLE 3 time cell correction factor

Wherein, the pressure refers to the current pressure, and the error refers to the error of the spraying amount per hectare.

Specifically, the level of the spraying error per hectare can be determined to be one of PB, PM, PS, AZ, NS and NM according to the difference between the real-time spraying amount per hectare and the target spraying amount per hectare, and the value of k is determined by combining the current pressure; finally, the corresponding time unit can be accurately calculated according to the value of k; and finally, according to the time unit, adjusting the real-time spraying amount in the spraying process by adopting a successive approximation method and adjusting the real-time flow of the spraying nozzle.

According to the variable spray control method provided by the invention, the hectare spray control method based on real-time hectare spray feedback is adopted, the hectare spray error is determined by comparing the real-time hectare spray with the target hectare spray, and the time unit of a successive approximation method is determined by combining the current pressure, so that the reduction and adjustment of the hectare spray error are realized, and the precision of the variable spray control is further improved.

Fig. 3 is a schematic structural diagram of a variable spray control device provided by the present invention, as shown in fig. 3, mainly including: data acquisition unit 31, first control module 32, second control module 33, third control module 34 and fourth control module 35, wherein:

the data acquisition unit 31 is mainly used for acquiring the real-time pressure and flow of the spray nozzle; the first control module 32 is mainly configured to adjust the real-time flow rate of the spray nozzle by using a pressure closed-loop fuzzy control method of feed-forward compensation according to the pressure until an error between the current pressure of the spray nozzle and a target pressure is smaller than a first error threshold; the second control module 33 is mainly used for continuously adjusting the real-time flow of the spray nozzle by adopting a real-time self-adaptive nozzle pressure and nozzle flow control method; the third control module 34 is mainly used for obtaining the real-time spraying amount of the hectare, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold; the iteration control module 35 is mainly used for controlling the data acquisition unit, the first control module, the second control module and the third control module to perform iteration operation until the spraying task is completed.

The variable spraying control device provided by the invention adopts a double closed-loop double fuzzy self-adaptive variable spraying control method, can overcome the influence of different pressure performance differences of a spray head and the like on the spraying precision in the variable spraying operation process, and effectively improves the precision of the variable spraying control device.

It should be noted that, when the device for improving train positioning accuracy provided in the embodiment of the present invention is in specific operation, the method for improving train positioning accuracy in any of the above embodiments may be executed, and details of this embodiment are not described herein.

Fig. 4 is a schematic structural diagram of a variable spray control system provided by the present invention, as shown in fig. 4, mainly including: the spraying device comprises a spraying nozzle, a controller, and a variable control valve, a flow sensor and a pressure sensor which are connected with the controller;

the flow sensor and the pressure sensor are both arranged in a pipeline connected with the variable control valve and the spray nozzle;

the flow sensor is used for acquiring the real-time flow of the spray nozzle in real time; the pressure sensor is used for acquiring the real-time pressure of the spray nozzle in real time;

the controller is configured to perform the steps of:

step S2, according to the pressure, adopting a pressure closed-loop fuzzy control method of feedforward compensation to adjust the real-time flow of the spray nozzle until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

step S3, adopting a real-time self-adaptive spray head pressure and flow control method to continuously adjust the real-time flow of the spray head;

step S4, acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold value;

and step S5, iteratively executing the steps S2 to S4 until the spraying task is completed.

Specifically, the invention is characterized in that a flow sensor and a pressure sensor are arranged in a pipeline connected with a variable control valve and a spray nozzle (spray nozzle for short), the flow sensor is used for measuring the flow of the spray nozzle in the pipeline, and the pressure sensor is used for measuring the pressure of the spray nozzle in the pipeline.

Then, the controller collects the data, and the method described in the above embodiment is adopted to iteratively execute the steps in the steps S2-S5 during the spraying process until the whole spraying task is completed.

The variable spray control system provided by the invention adopts a double closed-loop double fuzzy self-adaptive variable spray control method, can overcome the influence of different pressure performance differences of a spray head and the like on the spraying precision in the variable spraying operation process, and effectively improves the precision of the variable spray control device.

In order to more clearly show the advantages of the variable spray control method, device and system provided by the present invention, the following embodiments are first described.

1) The invention provides a variable spraying device which comprises the following components:

the whole spraying device adopts a Yongjia 3WP-500 type self-propelled boom sprayer, and comprises 22 spray heads with VP110 type No. 2 (the working pressure of the spray heads is 0.3-0.5Mpa), and the spray width is 11.5 meters. The variable spray control device provided by the invention is connected in series in a pipeline system of the self-propelled sprayer as shown in fig. 4. The variable spray control method provided by the invention is embedded into a controller of the variable spray control device, and the correction coefficient of the variable spray control method is displayed on a display screen of a control system.

2) Experiment one:

the spray heads of the self-propelled boom sprayer are replaced by 16 spray heads 3 and 6 spray heads 2, and the models of all the spray heads are assumed to be 3, so that the effectiveness of the variable spray control method provided by the invention is verified under the condition that the spray heads are worn.

In the experiment, a fixed engine with a speed of 2200r/Min was used, the simulated traveling speed was inputted into the piping system of the self-propelled sprayer, the traveling speed was fixed at 6.18km/h, and the target amount per hectare was changed successively, thereby obtaining one of the spray data tables shown in table 4:

TABLE 4 one of the spray data sheets

3) Experiment two:

the spray heads of the self-propelled boom sprayer are replaced by 16 spray heads 3 and 6 spray heads 2, and the models of all the spray heads are assumed to be 3, so that the effectiveness of the variable spray control method provided by the invention is verified under the condition that the spray heads are worn.

In the experiment, a fixed engine with the rotating speed of 2200r/Min is adopted, the simulated driving speed is input into a pipeline system of the self-propelled spraying machine, the driving speed is adjusted in a mode of decreasing from small to large, and the target spraying amount is gradually changed, so that a schematic diagram of the change of the driving speed and the spraying amount with time as shown in fig. 5 can be obtained.

4) Experiment three

The spray heads of the self-propelled boom sprayer are replaced by 16 spray heads 3 and 6 spray heads 2, and the models of all the spray heads are assumed to be 3, so that the effectiveness of the variable spray control method provided by the invention is verified under the condition that the spray heads are worn.

In the experiment, a fixed engine with the rotating speed of 2200r/Min is adopted, the simulated driving speed is input into a pipeline system of the self-propelled spraying machine, the driving speed is adjusted by adopting a random accelerator mode, and the target spraying amount is gradually changed, so that a second spraying data table shown in a table 5 can be obtained:

TABLE 5 spraying data Table II

5) Analysis on the effects of implementation:

in experiment one, the spraying errors are all less than 2.5%.

In experiment two, the real-time spraying amount can quickly follow the speed change, and besides the larger error of the speed change point, the errors of other operation points are smaller.

Experiment three: except that the error of the spraying amount 285L/Ha of the target per hectare is higher than 3 percent, the other errors are less than 2 percent, which shows that the control method is effective in the aspect of controlling the total spraying amount.

From the contents shown in table 4, fig. 5, and table 5 above, it can be understood that: the variable spray control method, the variable spray control device and the variable spray control system provided by the invention adopt the double closed-loop double fuzzy self-adaptive variable spray control method, can overcome the influence on the spraying precision caused by different pressure performance differences of the spray head in the variable spraying operation process, and effectively improve the precision of the variable spray control device.

Fig. 6 is a schematic structural diagram of an electronic device provided in the present invention, and as shown in fig. 6, the electronic device may include: a processor (processor)610, a communication Interface (Communications Interface)620, a memory (memory)630 and a communication bus 640, wherein the processor 610, the communication Interface 620 and the memory 530 are communicated with each other via the communication bus 640. The processor 610 may invoke logic instructions in the memory 630 to perform a variable spray control method comprising:

step S1, acquiring the real-time pressure and flow of the spray nozzle;

step S2, according to the pressure, adopting a pressure closed-loop fuzzy control method of feedforward compensation to adjust the real-time flow of the spray nozzle until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

step S3, adopting a real-time self-adaptive spray head pressure and flow control method to continuously adjust the real-time flow of the spray head;

step S4, acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold value;

and step S5, iteratively executing the steps S1 to S4 until the spraying task is completed.

In addition, the logic instructions in the memory 630 may be implemented in software functional units and stored in a computer readable storage medium when the logic instructions are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

In another aspect, the present invention also provides a computer program product comprising a computer program stored on a non-transitory computer readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform a variable spray control method provided by the above methods, the method comprising:

step S1, acquiring the real-time pressure and flow of the spray nozzle;

step S2, according to the pressure, adopting a pressure closed-loop fuzzy control method of feedforward compensation to adjust the real-time flow of the spray nozzle until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

step S3, adopting a real-time self-adaptive spray head pressure and flow control method to continuously adjust the real-time flow of the spray head;

step S4, acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold value;

and step S5, iteratively executing the steps S1 to S4 until the spraying task is completed.

In yet another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program being implemented by a processor to perform the variable spray control method provided in the above embodiments, the method including:

step S1, acquiring the real-time pressure and flow of the spray nozzle;

step S2, according to the pressure, adopting a pressure closed-loop fuzzy control method of feedforward compensation to adjust the real-time flow of the spray nozzle until the error between the current pressure and the target pressure of the spray nozzle is smaller than a first error threshold;

step S3, adopting a real-time self-adaptive spray head pressure and flow control method to continuously adjust the real-time flow of the spray head;

step S4, acquiring the real-time hectare spraying amount, and continuously adjusting the real-time flow of the spraying nozzle by adopting a hectare spraying amount control method based on real-time hectare spraying amount feedback until the error between the adjusted real-time hectare spraying amount and the target hectare spraying amount is smaller than a second error threshold value;

and step S5, iteratively executing the steps S1 to S4 until the spraying task is completed.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.