CN112269400B - Precise variable fertilization method and system for unmanned aerial vehicle - Google Patents

Abstract

The invention discloses a method and system for precise variable fertilization by unmanned aerial vehicle. The method includes: planning a route in combination with a fertilization prescription map of a target plot, and generating a waypoint plan; The flight speed and operating height of the man-machine operation calculate the landing time of the fertilizer, and predict the starting position of the drone when the discharged fertilizer just begins to fall into the corresponding area of the waypoint; Point the length and working width of the corresponding area to calculate the fertilizer discharge flow, generate fertilizer discharge control instructions, and cache them in advance, and preview when the UAV has not yet reached the target waypoint; read the current position of the UAV in real time, when there is no When the man-machine arrives at the starting position of the waypoint, the fertilizer discharge control system discharges the fertilizer according to the set flow. The invention can enable the drone to achieve precise variable fertilization according to the requirements of fertilizer requirements in different areas in the operation field, so as to avoid leakage of spraying or misplacement of fertilization areas.

Description

A method and system for precise variable fertilization by unmanned aerial vehicle

technical field

The invention relates to the technical field of unmanned aerial vehicle fertilization, in particular to a method and system for precise variable fertilization of unmanned aerial vehicles.

Background technique

As one of the main means of reducing costs and increasing efficiency in food production, the precise control of fertilizer application has always been the focus of research in the development of precision agriculture. Precision agriculture is based on "3S" technology and sensor technology, and is realized through intelligent control systems and decision-making algorithms. Agricultural production, improve resource utilization and agricultural production efficiency, reduce environmental pollution, reduce resource and labor costs, etc. Precise variable fertilization is to fertilize as needed under the premise of ensuring adequate nutrition according to the growth of crops, minimizing the use of fertilizers and improving the utilization rate of fertilizers.

Compared with ground fertilization machinery, the advantage of drone fertilization is that it has good passability. It can successfully complete tasks in areas where ground fertilization machinery is easy to get trapped or difficult to pass, and the stability, ease of use, The endurance and payload are constantly improving, and the application in agricultural production is becoming more and more extensive. The existing technologies of using drones for fertilization mainly include: the invention patent application with the publication number CN107097958A proposes a variable fertilization drone system and method, and designs a turntable mechanism with a horizontally arranged central axis. The number of grooves on the surrounding wall of the turntable realizes different fertilization efficiencies; the invention patent application with publication number CN107711018A proposes a variable fertilization device for unmanned aerial vehicles, which is equipped with a high-definition camera and a GPS locator to provide feedback information to regulate variable fertilization operations. The rotation speed of the motor and the number of troughs realize the adjustment of the amount of fertilization; the invention patent application with the publication number of CN107750542A proposes an unmanned aerial vehicle spreading device for fertilizer flow control and a control method thereof. Detect the fertilizer balance in the fertilizer box; the invention patent application with the publication number CN108773491A proposes a rapid fertilization device for agricultural drones, which uses a conveyor belt and a roller to discharge fertilizer, and throws the fertilizer out through the discharge pipe to spread around; authorized The invention patent with publication number CN106416530B proposes a multi-channel pneumatic unmanned aerial vehicle fertilizing device, which improves the uniformity of spreading and the controllability of fertilizer discharge; the invention patent application with publication number CN110920894A discloses a A method and system for spraying fertilizer by unmanned aerial vehicle based on satellite navigation. The application uses an input module by setting a display module, an input module, a CPU, a second feedback unit, a planning module, a database, a GPS positioning module, a driving module and a feedback unit one. Enter the longitude and latitude of the fertilization site, determine the fertilization area, and plan the spraying route through the planning module. The entire implementation process does not require remote control and is completely intelligent, and the fertilization box is installed directly below the bottom of the fixed plate to ensure that the drone is in the process of fertilization. The flight is stable, and the flight is not unstable due to the reduction of fertilizer, and the purpose of uniform fertilization is achieved. However, the above-mentioned existing technical solutions have the following deficiencies:

Due to the different types or growing conditions of crops, the amount of fertilizer required in each area is different; in addition, due to the inevitable delay of the fertilization actuator, and the operating height of the drone is usually high, it takes more time for the fertilizer particles to freely fall to the ground. For a long time, there is a relatively obvious delay phenomenon, and the flying speed of the UAV is relatively fast (usually above 4m/s). When fertilizing crops in multiple different areas, the above-mentioned prior art does not consider the influence of time delay, cannot accurately control the amount of fertilizer applied in each area, and cannot guarantee that the fertilizer with the expected amount of fertilizer application can be accurately sprinkled on the target crop area In the middle, there will be leakage of spraying or dislocation of the fertilization area, resulting in poor variable fertilization effect or even inability to achieve variable fertilization.

In addition, the existing variable fertilization control system suitable for ground fertilization machinery, such as the variable fertilization control system mentioned in the invention patent application with publication number CN101398677A, adjusts the electro-hydraulic proportional valve through the controller according to the prescription diagram to control the fertilization motor The system takes the ground fertilization machinery as the main body, and the operating conditions are different from those of the aerial drone; the invention patent application with publication number CN110809973A discloses a variable fertilization control device based on a light sensor, which uses an NDVI measuring instrument for information collection and The implementation is transmitted to the controller, and the improved nitrogen application optimization algorithm is used to calculate the amount of fertilizer required for variable application. The entire control device is installed on the variable fertilizer applicator. Due to the limited load of the drone, it is difficult to apply; the publication number is CN110780613A Invention patent application A variable fertilization control system is disclosed, which is mainly characterized in that the variable fertilization information is stored in an IC card, and a GIS system is used to control the fertilization amount according to the operation information of the fertilizer applicator. The variable fertilization control methods of the above-mentioned ground fertilization machinery are mostly matched with the ground mechanical power and the performance of the supporting devices. It is difficult to directly transplant the control logic and hardware structure into the fertilization control of the UAV, and it is not compatible with the operating height and flight speed of the UAV. It is difficult to be compatible with the delay time of the free fall of fertilizer particles to reach the ground.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above-mentioned problems and provide a method for precise variable fertilization by unmanned aerial vehicle, which can control the fertilization control system on the unmanned aerial vehicle to perform precise discharge according to the requirement of fertilizer demand in different areas in the operation field. , and can preview the target area to ensure that the fertilizer is accurately sprinkled in the corresponding area, and achieve precise variable fertilization.

Another object of the present invention is to provide a precise variable fertilization system for unmanned aerial vehicles.

The object of the present invention is achieved through the following technical solutions:

A method for precise variable fertilization by unmanned aerial vehicle, comprising the following steps:

(1) Preparation before operation: Combine the fertilization prescription map of the target plot, plan the route of the target plot, and generate a waypoint planning map. A waypoint in the waypoint planning map corresponds to a fertilization area in the prescription map. And record the prescription amount of the fertilization area corresponding to each waypoint; calibrate and save the control parameters for the target fertilizer in advance.

(2) The drone starts to operate, open the waypoint planning map, select the fertilizer type and the calibrated control parameters, set the flight parameters, spray parameters and operation mode, the drone precision variable fertilization system according to the planned route and prescription volume Execute job tasks, including:

(2.1) Calculate the landing time of fertilizer according to the flight speed and operating height of the drone operation, read the position of the waypoint and combine the landing time of the fertilizer to predict when the fertilizer discharged by the drone just falls into the The position of the drone when the starting boundary of the corresponding area is located, which is the starting position of the drone for the area corresponding to the waypoint; at the same time, the prescription amount of the waypoint is read and combined with the length of the corresponding area of the waypoint Calculate the fertilizer discharge flow with the working width, and generate the fertilizer control command, cache it in advance, and preview it when the drone has not yet reached the target waypoint;

(2.2), read the current position of the UAV in real time, when the UAV reaches the starting position of the operation at the waypoint, the fertilizer discharge control system executes the corresponding fertilizer discharge control command, and discharges the fertilizer according to the set flow;

(2.3) Repeat the above step (2.2) to achieve precise variable fertilization.

The working principle of the above-mentioned UAV precise variable fertilization method is as follows:

When working, firstly, plan the route of the target plot, and combine the fertilization prescription map of the target plot to generate a waypoint planning map. One waypoint in the waypoint planning map corresponds to a fertilization area, and obtain the Prescription amount, that is, the amount of fertilizer applied in each fertilization area; then set the operation parameters, and the drone flies according to the planned route; during the execution of the operation task, calculate the landing time of the fertilizer according to the flying speed and operation height of the drone operation, and read The position of the waypoint is combined with the described fertilizer landing time to predict the position of the drone when the fertilizer discharged by the drone just falls into the starting boundary of the corresponding area of the waypoint. The starting position of the operation in the area corresponding to the waypoint; at the same time, the prescription volume of the waypoint is read, and the fertilizer discharge flow is calculated according to the length and operation width of the corresponding area of the waypoint, and the fertilizer discharge control command is generated, cached in advance, and stored in the UAV. Preview before reaching the target waypoint to ensure that the drone can immediately execute the fertilizer control command when it reaches the starting position of the operation in the area corresponding to the target waypoint, so as to avoid missed spraying and wrong spraying caused by time delay; then, Read the current position of the drone in real time. When the drone reaches the start position of the waypoint, the fertilizer discharge control system discharges fertilizer according to the set flow; when spraying the next waypoint, repeat the above Step 1: Read the current position of the drone in real time, and when it is detected that the drone reaches the starting position of each waypoint, the fertilizer discharge control system discharges the fertilizer according to the set flow, and so on. If multiple waypoints are located on the same route, when the spraying of one waypoint is completed, immediately switch the fertilizer discharge flow in the area corresponding to the next waypoint to discharge fertilizer, and when the spraying in the area corresponding to the last waypoint of the route is completed , then stop fertilizing until the drone enters the next route, repeat the above steps, according to the prescription amount of the corresponding area of each waypoint, the fertilizer control system discharges fertilizer according to the set flow, and sprays the corresponding area of the waypoint Operation.

A preferred solution of the present invention further includes step (3): after the fertilization of all fertilization areas of the target plot is completed, the drone automatically returns to the landing point for landing.

Preferably, in step (2.1), before the drone takes off, the fertilizer landing time is calculated by the following formula:

Among them, H is the set working height, T3 is the landing time _of the fertilizer, F is the resultant force during the falling process of the particles, including gravity, air resistance and the force of the rotor wind field, and m is the mass of the particles.

In order to avoid missed spraying or misplacement of the fertilization area, when the fertilizer discharged by the drone at the starting position of the operation falls to the starting boundary of the corresponding area of the target waypoint, the drone should not have left the corresponding area of the waypoint at this time. , that is, each parameter should satisfy the following conditions:

Among them, V _fly is the flight speed set by the drone, T ₃ is the landing time of the fertilizer, and A is the length of the area corresponding to the waypoint.

Preferably, in step (2.1), the UAV flies according to the set operating speed and operating altitude, and the on-board master control system automatically reads the information of the first waypoint, and predicts the UAV operation corresponding to this waypoint. Start position and calculate the fertilizer discharge flow, generate fertilizer discharge control instructions, and save them in the buffer; when the frequency is f, read and parse the information of subsequent waypoints on the route in real time, and convert them into fertilizer discharge control instructions , stored in the buffer, when the UAV reaches the operation starting position of the target waypoint, the on-board master control system sends the fertilizer discharge control command to the fertilizer discharge control system in turn, wherein the frequency is calculated by the following formula:

Among them, T ₀ is the response time of the on-board master control system.

When the drone reaches the starting position of the first waypoint, the fertilizer control commands to be sent for the first n waypoints have been cached. During this process, in order to ensure that the drone is performing the current task, To be able to preview the information in the fertilization waypoints in a timely manner, the following conditions must be met:

T ₀ × V Fe _≤ nA

A preferred solution of the present invention, wherein, in step (1), a remote sensing image is obtained by using a spectral camera mounted on an unmanned aerial vehicle, and the processed spectral image features are matched with the crop growth conditions, and the crop standards of the same period under standard planting are matched. The growth model is used to obtain the fertilizer requirements of the crops in the target plot corresponding to the current image, and generate the corresponding fertilization prescription map.

Preferably, in step (1), according to the map of the target plot, the UAV flight route is planned on the basis of the fertilization prescription map, the target waypoint and the corresponding area of the prescription map are matched, and the waypoint planning map is generated.

Preferably, in the above steps, when planning a route for the target plot, each target plot has at least one route, and each route has at least one waypoint. When the spraying of one waypoint on one route is completed, Repeat the above step (2.2) to spray the next waypoint to achieve precise variable fertilization; when the spraying of the area corresponding to the last waypoint in the route is completed, stop fertilizing until the drone enters the next route. Repeat steps (2.1)-(2.3).

A precise variable fertilization system for unmanned aerial vehicles, comprising an on-board master control system, a positioning and speed measurement system, a ground control station and a fertilizer discharge control system, wherein the positioning and speed measurement system, the ground control station and the fertilizer discharge control system are respectively connected with the on-board control system. Communication connection with the master control system; the ground control station is used to generate a waypoint plan and set parameters, and send them to the onboard master control system; the positioning and speed measurement system is used to obtain the position and flight parameters of the UAV in real time and transmit them To the on-board master control system;

The on-board master control system is used to control the drone to fly autonomously according to the waypoint plan, and to calculate the landing time of the fertilizer according to the flight speed and operation height of the drone, by reading the position of the waypoint and combining the fertilizer Landing time, predict the position of the drone when the fertilizer discharged by the drone just falls on the starting boundary of the corresponding area of the waypoint, and determine the starting position of the drone for the waypoint. Read the prescription volume of the waypoint, and calculate the fertilizer discharge flow in combination with the length and operation width of the corresponding area of the waypoint, and generate the fertilizer discharge control command; the on-board master control system is also used for real-time monitoring without The current position of the man-machine, when the unmanned aerial vehicle reaches the operation starting position of the waypoint, the on-board master control system sends a control command to the fertilizer discharge control system;

The fertilizer discharge control system is used for discharging fertilizer according to the set flow rate according to the instruction of the on-board master control system.

Preferably, it also includes a residual detection system and a pneumatic conveying control system, wherein the residual detection system and the pneumatic conveying control system are respectively connected in communication with the on-board master control system, and the residual detection system is used for real-time monitoring of the unmanned aerial vehicle feeding box The amount of fertilizer in the machine is sent to the general control on the machine for processing. The pneumatic conveying control system is used to control the wind speed of blowing out fertilizer and adjust the working width.

Preferably, the fertilizer discharge control system includes a fertilizer discharge motor provided on the drone, a drive controller for controlling the speed of the fertilizer discharge motor, and a rotational speed sensor set on the drive controller for detecting the speed of the fertilizer discharge motor.

Preferably, the on-board master control system includes a single-chip microcomputer chip and a CAN bus, wherein the single-chip microcomputer chip receives the UAV flight speed, operating height and position coordinate information sent by the positioning and speed measurement system through the CAN bus, and receives the information from the ground control station. The sent waypoint planning map, operation parameters and feedback information are used for the internal calculation of the single-chip microcomputer chip, and the fertilizer discharge command is sent to the fertilizer discharge control system.

Compared with the prior art, the present invention has the following beneficial effects:

1. In the present invention, by combining the fertilization prescription map of the target plot and the planned route, a waypoint plan is generated in advance before the operation, and the waypoint plan contains both the route information during the operation of the drone, and the In the process of UAV operation, according to the waypoint planning map, the prescription volume of each waypoint in the route can be quickly obtained, and the variable operation can be carried out according to the set route, thus greatly reducing the data processing time. Time, so that the UAV can calculate the prescription volume of each waypoint in real time, quickly and accurately during the operation, so as to realize precise fertilizer control and precise variable fertilization according to the prescription volume.

2. During the operation of the unmanned aerial vehicle of the present invention, the prescription quantity of the fertilization area corresponding to each waypoint is obtained in real time, and the landing time of the fertilizer is calculated according to the flying speed and operation height of the unmanned aerial vehicle, and the information of the waypoint is read. Combined with the described fertilizer landing time, predict the position of the UAV when the fertilizer discharged by the UAV just falls on the starting boundary of the corresponding area of the waypoint, and this position is the UAV targeting the waypoint. At the same time, read the prescription volume of the waypoint, and calculate the fertilizer discharge flow in combination with the length of the corresponding area of the waypoint and the operation width, so as to generate the fertilizer discharge control command for each waypoint. The fertilizer control instructions are pre-calculated during the operation of the UAV to realize the waypoint preview, so that when the UAV reaches the operation starting position of the waypoint, the fertilizer control system can immediately press the set value. The fertilization control command discharges fertilizer, thereby reducing the delay error, and there will be no leakage of spraying or dislocation of the fertilization area, so that each waypoint can achieve precise fertilization according to the set prescription amount, which greatly improves the variable fertilization operation of the drone. of accuracy.

Description of drawings

FIG. 1 is a schematic process diagram of a method for precise variable fertilization by UAV in the present invention.

FIG. 2 is a control flow chart of the precise variable fertilization of a method for precise variable fertilization of an unmanned aerial vehicle according to the present invention.

FIG. 3 is a schematic diagram of the operation mode decision-making process of a UAV precise variable fertilization method according to the present invention.

Fig. 4 is a flow chart of variable decision-making in the process of executing a route of a UAV precise variable fertilization method according to the present invention.

FIG. 5 is a schematic diagram of the process of variable fertilization and preview of the area corresponding to the waypoint in a method for precise variable fertilization of an unmanned aerial vehicle according to the present invention.

FIG. 6 is a process diagram of generating a waypoint planning diagram of a method for precise variable fertilization of an unmanned aerial vehicle according to the present invention.

FIG. 7 is a schematic diagram of the composition of a UAV precise variable fertilization system in the present invention.

FIG. 8 is a schematic diagram of the working process of a UAV precise variable fertilization operation in the present invention.

FIG. 9 is a schematic diagram of a man-machine interaction interface of a ground control station in a UAV precise variable fertilization system according to the present invention.

Detailed ways

In order to make the technical solutions of the present invention well understood by those skilled in the art, the present invention will be further described below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

Referring to Fig. 1-Fig. 2 and Fig. 7-Fig. 8, the present embodiment discloses a method for precise variable fertilization by unmanned aerial vehicle, including the following steps:

(1) Preliminary preparation: For different fertilizers, at the specific speed of the fertilizer discharge motor, the control parameters are calibrated and saved by counting the fertilizer discharge amount for one minute.

(2) Preparation before operation: Open the ground control station, connect to the on-board master control system, import the fertilization prescription map of the target plot, plan the route for the target plot, and generate the waypoint planning map. One waypoint corresponds to one fertilization area, and the fertilization prescription amount of the corresponding area of each waypoint is recorded.

(3) The drone starts to operate, open the waypoint planning map, select the fertilizer type and the calibrated control parameters, set the flight parameters, spray parameters and operation mode, the drone precision variable fertilization system according to the planned route and prescription volume Execute job tasks, including:

(3.1) Calculate the landing time of fertilizer according to the flight speed and operating height of the drone operation, read the position of the waypoint and combine the landing time of the fertilizer to predict when the fertilizer discharged by the drone just falls into the The position of the UAV at the starting boundary of the corresponding area, which is the starting position of the UAV for this waypoint; at the same time, read the prescription amount of the waypoint, and combine the length of the area corresponding to the waypoint and the operation The width calculates the fertilizer discharge flow, and generates the fertilizer discharge control command, which is cached in advance and previewed when the UAV has not yet reached the target waypoint;

(3.2) The UAV reads the current position of the UAV in real time through the positioning and speed measurement system. When the UAV reaches the starting position of the waypoint, the fertilizer discharge control system discharges fertilizer according to the set flow;

(3.3), repeat the above step (3.2) to achieve precise variable fertilization.

(4) After the fertilization operation is completed, the ground control station will receive a prompt, and the drone will automatically return to the destination and land at the indicated location.

Referring to Fig. 2, in the above steps, when planning the route for the target plot, each target plot has at least one route, and each route has at least one waypoint. When fertilizing, repeat the above step (3.2) to spray the area corresponding to the next waypoint to achieve precise variable fertilization; when the spraying of the area corresponding to the last waypoint in the route is completed, stop fertilizing until the drone enters For the next route, repeat steps (3.1)-(3.3).

Referring to Figure 6 and Figure 7, in step (2), remote sensing images are obtained by using a spectral camera mounted on an unmanned aerial vehicle, and the processed spectral image features are matched with the crop growth condition, and the standard crop growth model of the same period under standard planting is used. , to obtain the fertilizer requirement of the crops in the target plot corresponding to the current image, and generate the corresponding fertilization prescription map.

Referring to FIG. 6 and FIG. 7 , in step (2), according to the map of the target plot, plan the route on the basis of the fertilization prescription map, and generate the waypoint planning map.

Referring to FIG. 3, in step (2), the operation modes are divided into three types, namely flow mode, mu consumption mode and prescription map mode, wherein, the flow mode is determined by setting the flow value (the discharge per minute). Fertilizer amount), query the flow-speed calibration table, change the speed of the fertilizer discharge motor, and control the spraying of fertilizer; the said mu consumption mode takes mu consumption demand, operation width and UAV flight speed as decision-making parameters, through fertilization decision-making The model outputs the corresponding flow value; the prescription map mode is to convert the prescribed amount given on the prescription map into the amount per mu, and output the corresponding flow value through the fertilization decision model.

Further, the rotation speed of the fertilization decision model converted into the fertilization motor is calculated by the following algorithm;

q=f ₁ (N) (1)

Q=f ₂ (q) (2)

Wherein, the N is the rotational speed of the fertilizer discharge motor, q is the fertilizer discharge amount per minute, Q is the amount per mu, and f ₁ and f ₂ are linear or nonlinear fitting functions.

Referring to Figure 1 and Figure 2, in steps (2) and (3), before the drone takes off, the fertilizer landing time is calculated by the following formula:

Among them, H is the set working height, T3 is the landing time _of the fertilizer, F is the resultant force during the falling process of the particles, including gravity, air resistance and the force of the rotor wind field, and m is the mass of the particles.

In order to avoid missed spraying or misplacement of the fertilization area, when the initially discharged fertilizer falls to the operation start boundary of the area corresponding to the target waypoint, the drone should have not left the fertilization area, and there is enough time for the next waypoint corresponding to the UAV. To prepare for the fertilization operation in the area, each parameter should meet the following conditions:

Among them, V _fly is the flight speed set by the drone, T ₃ is the landing time of the fertilizer, and A is the length of the area corresponding to the waypoint.

Referring to Figure 1 and Figure 2, in step (3.1), the UAV flies at the set operating altitude, and the onboard master control system automatically reads the information of the first waypoint, and predicts the UAV corresponding to this waypoint. The starting position of the operation and the fertilizer discharge flow in the target area are calculated, and the fertilizer discharge control command is generated and saved in the buffer; when the frequency is f, the information of the nth waypoint is read and analyzed in real time in turn, and the fertilizer discharge control command is generated. The instruction is stored in the buffer and sent to the fertilizer control system, wherein the frequency is calculated by the following formula:

Wherein, T ₀ is the response time of the on-board master control system in the UAV precise variable fertilization system of the present invention.

Further, when the drone reaches the operation start position of the first waypoint, the fertilizer control commands to be sent for the first n waypoints have been cached. During this process, in order to ensure that the drone performs the current operation task, To be able to preview the information in the fertilization waypoints in a timely manner, the following conditions must be met:

T ₀ ×Vf _≤nA (6)

Referring to Figure 4, in the process of executing the route, the on-board master control system will prejudge the waypoint when making the spraying decision according to the information in the prescription map, that is, when the UAV is performing the current spraying task, the subsequent waypoints will The location information will be read and matched with the information in the prescription map. If there is no error, the information of the waypoint will be converted into fertilizer control instructions and sent to the fertilizer control system to drive the fertilizer motor to continue operation. If the waypoint is not in the prescription map, the fertilization amount will be forced to be set to 0 (ie no spraying operation), and then continue to read the position information of the next waypoint. This cycle of detection is performed until the fertilization amount information in the area corresponding to the next waypoint in the prescription map is correct, and the fertilization task continues to be executed until the execution of the route is completed.

Specifically, as shown in formula (6), it is assumed that the distance between the position of the _drone when the speed of the drone reaches the set value V and the time when the information of the prescription map of the n-th waypoint in the future is read is L (L=n ×A), then L is a function of the flight speed V. When the UAV is flying at a faster speed, L is larger; on the contrary, when the UAV is flying at a slower speed, L is smaller to ensure the waypoint Position information can be transmitted to the control system accurately and efficiently.

In addition, the UAV will adjust the operation parameters according to the forecast information. For example, when the fertilization amount in the corresponding area of the adjacent waypoint is basically the same, the flight speed of the drone can be adjusted appropriately, and it can be adjusted faster or slower by a small increment. The flight parameters will be fed back to the control system for measurement.

Referring to Figure 5, in step (3.2), the UAV receives the information of the positioning and speed measurement system, reads the position coordinates of the UAV in real time, and compares it with the coordinate information in the stored fertilizer control instructions. When the drone arrives at the starting position of the operation in the corresponding area of waypoint 1, send the execution fertilizer control command to the fertilizer motor in the fertilizer control system to adjust the speed of the fertilizer motor. When the drone flies for a period of time After (T ₃ ), the initially discharged fertilizer just falls on the operation starting boundary of the corresponding area of waypoint 1, and continues to fall continuously in the forward direction of the UAV, forming a blanking belt with a certain width. The on-board master control system continuously receives the positioning information of the positioning and speed measurement system, updates and compares it in real time, until it detects the operation start boundary of the area corresponding to the second waypoint, then sends the execution fertilizer control command corresponding to the waypoint to adjust the The speed of the fertilization motor reaches the new fertilization rate. This cycle occurs as the drone flies along the route. When the drone reads and parses the information of the last waypoint on the route, it automatically reads the prescription map information of the next route to be executed, and continues to parse and convert. At this time, the UAV has not completed the spraying task of the current route, and it is necessary to continue to perform step (3.2) until it detects the starting position of the UAV in the area corresponding to the last waypoint, and starts to execute the operation in the area corresponding to the waypoint. spraying work. In order to avoid missed spraying or misplacement of the fertilization area, the UAV needs to fly away from the end boundary of the area corresponding to the last waypoint for a period of time (T ₃ ) to ensure that the operation is performed to the end boundary.

Referring to Figure 1-Figure 2 and Figure 7-Figure 8, the working principle of the above-mentioned precise variable fertilization method by UAV is:

When working, firstly, combined with the fertilization prescription map of the target plot, plan the route of the target plot, and generate a waypoint planning map. One waypoint in the waypoint planning map corresponds to a fertilization area, and obtain the Prescription amount, that is, the amount of fertilizer applied in each fertilization area; then set the operation parameters, and the drone flies according to the planned route; during the execution of the operation task, calculate the landing time of the fertilizer according to the flying speed and operation height of the drone, and read the flight path. The position of the point and combined with the fertilizer landing time, predict the position of the UAV when the fertilizer discharged by the UAV just falls into the starting boundary of the corresponding area of the waypoint. The operation starting position of the waypoint; at the same time, read the prescription amount of the waypoint, and calculate the fertilizer discharge flow according to the length and operation width of the corresponding area of the waypoint; then, read the current position of the UAV in real time. When reaching the starting position of the operation at the waypoint, the fertilizer discharge control system discharges fertilizer according to the set flow rate; when spraying the area corresponding to the next waypoint, repeat the above steps to read the current position of the drone in real time, When it is detected that the drone arrives at the starting position of the operation of each waypoint, the fertilizer discharge control system discharges the fertilizer according to the set flow, and so on. If multiple waypoints are located on the same route, when the spraying of the corresponding area of one waypoint is completed, immediately switch the fertilizer flow rate of the corresponding area of the next waypoint for spraying. When the spraying of the corresponding area of the last waypoint of the route is completed, the When applying, stop the fertilizer discharge until the drone enters the next route, repeat the above steps, control the fertilizer discharge control system according to the prescription amount of the corresponding area of each waypoint, discharge fertilizer according to the set flow, and spray the waypoint. .

Referring to FIGS. 7 and 8 , this embodiment also discloses a UAV precise variable fertilization system, including an on-board master control system, a positioning and speed measurement system, a ground control station, a fertilizer discharge control system, a surplus detection system, and a pneumatic conveying control system. system, wherein the positioning and speed measurement system, the ground control station, the fertilizer discharge control system, the residual detection system and the pneumatic conveying control system are respectively connected to the on-board master control system; the ground control station is used to generate a waypoint planning map And set parameters, and send them to the on-board master control system; the positioning and speed measurement system is used to obtain the position and flight parameters of the UAV in real time and transmit them to the on-board master control system;

The on-board master control system is used to control the drone to fly autonomously according to the waypoint plan, and to calculate the landing time of the fertilizer according to the flight speed and the working height of the drone. By reading the position of the waypoint and combining the fertilizer landing time Time, predict the position of the drone when the fertilizer discharged by the drone just falls on the starting boundary of the corresponding area of the waypoint, and determine the starting position of the drone for the waypoint. Take the prescription volume of the waypoint, and calculate the fertilizer discharge flow in combination with the length and operation width of the corresponding area of the waypoint, and generate the fertilizer discharge control command; the on-board master control system is also used for real-time detection of unmanned persons through the positioning and speed measurement system The current position of the aircraft, when the drone reaches the operation start position of the waypoint, the on-board master control system sends a fertilizer discharge control command to the fertilizer discharge control system;

The fertilizer discharge control system is used to execute the fertilizer discharge control instruction sent by the on-board master control system, and discharge fertilizer according to the set flow rate.

The residual quantity detection system is used for real-time detection of the fertilizer amount on the drone, and the detection information is sent to the on-board master control for processing. The pneumatic conveying control system is used to control the wind speed of the blown fertilizer and adjust the spray width. The UAV precision variable fertilization system is based on the on-board master control system, combined with the positioning and speed measurement system and the fertilizer control system to achieve precise control of the fertilizer flow in the corresponding areas of different waypoints in the target plot, and can be used during spraying operations. According to the information in the prescription map, the information on the waypoint is predicted to reduce the delay error of the system response.

Referring to Figures 7 and 8, the on-board master control system includes a single-chip microcomputer chip and a CAN bus. The single-chip microcomputer chip adopts the STM32 series, and receives the UAV flight speed, operating height and position coordinate information sent by the positioning and speed measurement system through the CAN bus. , and receive the waypoint planning map, operation parameters and feedback information sent by the ground control station, combined with the variable fertilization decision model, through the internal calculation of the single chip chip, output control commands and display information to each mechanism module.

Referring to Figure 7 and Figure 8, the fertilizer discharge control system includes a fertilizer discharge motor arranged on the drone, a drive controller for controlling the speed of the fertilizer discharge motor, and a drive controller for detecting the speed of the fertilizer discharge motor. A rotational speed sensor, wherein the fertilizer discharge motor and the drive controller are integrated, and the rotational speed sensor is built in the drive controller to facilitate the measurement of the rotational speed of the fertilizer discharge motor shaft.

Referring to Figure 7 and Figure 8, the pneumatic conveying control system realizes the control of the wind speed in the pneumatic channel by controlling the rotational speed of the fan, and realizes low-altitude wide-width spraying. , using PWM signal regulation. For the specific structure of the above-mentioned fertilizer discharge control system and pneumatic conveying control system, reference is made to a fertilizer spreading device mounted on an agricultural unmanned aerial vehicle disclosed in the invention patent with the authorization announcement number CN106416530B.

Referring to FIG. 7 and FIG. 8 , the residual detection system includes a photoelectric sensor and a detection signal output circuit.

Referring to FIG. 7 and FIG. 8 , the positioning and speed measurement system includes a GNSS positioning module, a speed measurement module, 4G-LTE and a data transmission station, wherein the GNSS positioning module and the speed measurement module are integrated on the main control board.

Referring to Fig. 9, the ground control station is operated through the human-computer interaction interface. The ground control station is based on the Android system, which can control the switches of each system, the import of the fertilization prescription map, the selection of the plot and the waypoint planning map. Generation, operation parameter setting, fertilizer and operation mode selection and calibration, etc., it can also display key information such as operation information, flight status information and residual detection alarm prompt in real time.

The above is the preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned content, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention, All should be equivalent replacement modes, which are all included in the protection scope of the present invention.

Claims (9)

1. an unmanned aerial vehicle precise variable fertilization method, is characterized in that, comprises the following steps: (1) Preparation before operation: Combine the fertilization prescription map of the target plot, plan the route of the target plot, and generate a waypoint planning map. A waypoint in the waypoint planning map corresponds to a fertilization area in the prescription map. And record the prescription amount of the fertilization area corresponding to each waypoint; calibrate and save the control parameters for the target fertilizer in advance; (2) The drone starts to operate, open the waypoint planning map, select the fertilizer type and the calibrated control parameters, set the flight parameters, spray parameters and operation mode, and the drone precision variable fertilization system will follow the planned route and fertilization prescription. Quantitatively perform spraying tasks, including: (2.1) Calculate the landing time of fertilizer according to the flight speed and operating height of the drone operation, read the position of the waypoint and combine the landing time of the fertilizer to predict when the fertilizer discharged by the drone just falls into the The position of the drone when the starting boundary of the corresponding area is located, which is the starting position of the drone for the area corresponding to the waypoint; at the same time, the prescription amount of the waypoint is read and combined with the length of the corresponding area of the waypoint Calculate the fertilizer discharge flow with the working width, and generate the fertilizer control command, cache it in advance, and preview it when the drone has not yet reached the target waypoint; (2.2) Read the current position of the drone in real time. When the drone reaches the starting position of the operation, the fertilizer control system executes the fertilizer control command, discharges the fertilizer according to the set flow, and sprays it on the target fertilization area; (2.3), repeat the above step (2.2) to achieve precise variable fertilization; In step (2.1), before the drone takes off, the fertilizer landing time is calculated by the following formula:

Among them, H is the set working height, T3 is the landing time _of the fertilizer, F is the resultant force during the falling process of the particles, including gravity, air resistance and the force of the rotor wind field, and m is the particle mass; In order to avoid missed spraying or misplacement of the fertilization area, when the fertilizer discharged by the drone at the starting position of the operation falls within the starting boundary of the corresponding area of the waypoint, the drone should not have left the area, that is, the parameters should meet the following conditions :

Among them, V _fly is the flight speed set by the drone, T ₃ is the landing time of the fertilizer, and A is the length of the area corresponding to the waypoint. 2. a kind of UAV precise variable fertilization method according to claim 1, is characterized in that, in step (2.1), UAV flies according to set flight speed and working height, and the on-board master control system automatically reads Take the information of the first waypoint on the route, predict the starting position of the operation in the corresponding area of the waypoint and calculate the fertilizer discharge flow, generate the fertilizer discharge control command, and save it in the buffer; according to a certain frequency f, read it in real time in sequence And analyze the information of the subsequent waypoints on the route, when the UAV reaches the starting position of the operation, the on-board master control system sends the fertilizer control command to the fertilizer control system, wherein the frequency is determined by the following formula calculate:

Among them, T ₀ is the response time of the UAV precise variable fertilization system; When the drone arrives at the starting position of the operation in the area corresponding to the first waypoint, the fertilizer control commands to be sent for the first n waypoints have been cached, and each parameter must meet the following conditions: T ₀ × V Fe _≤ nA Among them, V _fly is the flight speed set by the drone, and A is the length of the area corresponding to the waypoint. 3. a kind of UAV precise variable fertilization method according to claim 1, is characterized in that, in step (1), by UAV carrying spectral camera to obtain remote sensing image, the spectral image feature after processing and crop The growth conditions are matched, and according to the standard crop growth model of the same period under standard planting, the fertilizer requirements of the crops in the target plot corresponding to the current image are obtained, and the corresponding fertilization prescription map is generated. 4. a kind of UAV precise variable fertilization method according to claim 1 or 3, is characterized in that, in step (1), according to the map of target plot, plan out UAV on the basis of fertilization prescription map The flight route matches the information of the target waypoint and the corresponding area of the prescription map to generate the waypoint planning map. 5. A kind of UAV precise variable fertilization method according to claim 1, is characterized in that, in the above-mentioned steps, when carrying out route planning to the target plot, each target plot has at least one route, and each route has at least one route. There is at least one waypoint. When the spraying of the corresponding area of a waypoint on a route is completed, repeat the above step (2.2) to spray the corresponding area of the next waypoint to achieve precise variable fertilization; Stop fertilizing when spraying in the area corresponding to the last waypoint, and repeat steps (2.1)-(2.3) until the drone enters the next route. 6. A UAV precise variable fertilization system for realizing the UAV precise variable fertilization method according to any one of claims 1-5, characterized in that it comprises an on-board master control system, a positioning and speed measurement system, a ground A control station and a fertilizer discharge control system, wherein the positioning and speed measurement system, the ground control station and the fertilizer discharge control system are respectively connected in communication with the on-board master control system; the ground control station is used to generate a waypoint plan and set parameters, and send it to the on-board master control system; the positioning and speed measurement system is used to obtain the position and flight parameters of the UAV in real time and send it to the on-board master control system; The on-board master control system is used to control the drone to fly autonomously according to the waypoint plan, and calculate the landing time of the fertilizer according to the flight speed and the working height of the drone. By reading the waypoint information and combining the landing time of the fertilizer , predict the position of the drone when the fertilizer discharged by the drone just falls on the starting boundary of the corresponding area of the waypoint, and determine the starting position of the drone for the waypoint. The prescribed amount of the waypoint, combined with the length and operation width of the corresponding area of the waypoint, calculate the fertilizer discharge flow, and generate the fertilizer discharge control command; the on-board master control system is also used to detect the UAV in real time through the positioning and speed measurement system. The current position of the drone, when the drone arrives at the start position of the waypoint, the on-board master control system sends a fertilizer control command to the fertilizer control system; The fertilizer discharge control system is used to execute the fertilizer discharge control instructions of the on-board master control system, and discharge fertilizer according to the set flow rate. 7 . The precise variable fertilization system for unmanned aerial vehicles according to claim 6 , further comprising a residual detection system and a pneumatic conveying control system, wherein the residual detection system and the pneumatic conveying control system are respectively connected with the on-board total control system. 8 . Communication connection with the control system, the residual detection system is used to detect the fertilizer amount in the fertilizer tank on the drone in real time, and the detection information is sent to the general control system on the aircraft for processing. The pneumatic conveying control system is used to control the wind speed of blowing out fertilizer. , adjust the working width. 8. The precise variable fertilization system for an unmanned aerial vehicle according to claim 6 or 7, wherein the fertilization control system comprises a fertilization motor arranged on the unmanned aerial vehicle, a fertilization motor for controlling the rotational speed of the fertilization motor. A drive controller and a rotational speed sensor arranged on the drive controller for detecting the rotational speed of the fertilizer discharge motor. 9. A UAV precision variable fertilization system according to claim 6 or 7, wherein the on-board master control system comprises a single-chip microcomputer chip and a CAN bus, wherein the single-chip microcomputer chip receives the positioning and speed measurement system through the CAN bus The flight speed, operation height and position coordinate information of the UAV sent, and the waypoint planning map, operation parameters and operation feedback information sent by the ground control station are received, and the internal calculation of the single-chip chip is performed, and the fertilizer removal control system is sent to the fertilizer control system. Control instruction.

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