A system and method for online detection of spray droplet deposition effect of a boom sprayer

Abstract

This invention proposes an online detection system and method for droplet deposition effect of a boom sprayer, comprising: a boom sprayer trajectory maintenance control unit for ensuring that the boom sprayer's trajectory remains unchanged during normal operation; a water-sensitive paper positioning unit for acquiring the position of the water-sensitive paper before spraying to detect droplet deposition effect; a boom sprayer speed measurement unit for measuring the speed of the boom sprayer; a droplet deposition effect information acquisition unit for acquiring image information of the water-sensitive paper after spraying; and an online droplet deposition effect information detection unit for calculating information characterizing the droplet deposition effect in real time based on the acquired position of the water-sensitive paper, the speed of the boom sprayer, and the image information of the water-sensitive paper after spraying.

Description

Technical Field

[0001] This invention belongs to the field of online detection technology for plant protection machinery, and particularly relates to an online detection system and method for the droplet deposition effect of a boom sprayer. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] A boom sprayer is a plant protection machine widely used in agriculture, landscaping, lawns and other fields. It is mainly used to spray liquids such as pesticides, herbicides and foliar fertilizers, and has the characteristics of high efficiency, uniformity and adjustability.

[0004] When evaluating the performance and spray quality of a sprayer, a spray droplet deposition test is required. This test is a key step in assessing the spray quality, uniformity of pesticide distribution, and control efficacy. It mainly involves the measurement of parameters such as droplet size, coverage density, and deposition amount. This test is of great value in optimizing spray effects, evaluating spray quality, assessing environmental impact, and promoting technological innovation.

[0005] However, current spray droplet deposition tests typically involve manually deploying numerous droplet collectors such as water-sensitive paper and stainless steel mesh in the field before spraying; after spraying, the collected droplets are sent to a laboratory for analysis. This field-laboratory analysis method is complex, time-consuming, and the results are easily affected by human factors.

[0006] In addition, the inventors discovered in their research that although there are related technical solutions in the prior art for actively controlling the operating parameters of boom sprayers based on the perception of the working environment, and for actively controlling the spraying parameters by acquiring dynamic information of the field working environment and the speed of the equipment through the CAN bus, it is still impossible to achieve online detection of the spraying effect. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, this invention provides an online detection system for the spray droplet deposition effect of a boom sprayer, which can realize real-time detection of spray effect, simplify the test process, improve detection efficiency, and provide a strong basis for real-time adjustment of spray parameters and intelligent plant protection.

[0008] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0009] In the first aspect, an online detection system for the droplet deposition effect of a boom sprayer is disclosed, comprising:

[0010] The boom sprayer travel trajectory maintenance control unit is used to ensure that the travel trajectory of the boom sprayer remains unchanged during normal operation;

[0011] The water-sensitive paper positioning unit is used to obtain the position of the water-sensitive paper before spraying to detect the droplet deposition effect;

[0012] The boom sprayer travel speed measurement unit is used to measure the travel speed of the boom sprayer.

[0013] The droplet deposition effect information acquisition unit is used to acquire image information of the water-sensitive paper after spraying;

[0014] The online detection unit for droplet deposition effect information calculates information characterizing the droplet deposition effect in real time based on the acquired position of the water-sensitive paper, the travel speed of the boom sprayer, and the image information of the water-sensitive paper after spraying.

[0015] As a further technical solution, the boom sprayer trajectory maintenance control unit ensures that the boom sprayer's trajectory remains unchanged during normal operation, while the water-sensitive paper positioning unit, boom sprayer speed measurement unit, droplet deposition effect information acquisition unit, and droplet deposition effect information online detection unit operate normally.

[0016] As a further technical solution, the boom sprayer travel trajectory maintenance control unit includes:

[0017] The system includes a limit switch, a steering angle sensor, a controller, an electromagnetic proportional directional valve, and a steering cylinder. The limit switch is installed on the left and right wheels of the boom sprayer. Both the limit switch and the steering angle sensor are connected to the controller to transmit the collected information. The controller is connected to the steering cylinder via the electromagnetic proportional directional valve, and the steering cylinder is used to control the movement of the steering wheels.

[0018] As a further technical solution, the water-sensitive paper positioning unit includes a first image acquisition unit, which is installed at the middle of the front end of the spray bar of the spray bar sprayer and transmits the acquired image to the industrial control computer via a bus. The industrial control computer determines the position of the water-sensitive paper based on the acquired image.

[0019] As a further technical solution, the boom sprayer travel speed measurement unit includes a speed encoder, which is installed at a set position on the sprayer wheels to measure the rotational speed of the front and rear wheels of the boom sprayer and send the acquired information to the industrial control computer via a bus.

[0020] As a further technical solution, the droplet deposition effect information acquisition unit includes a second image acquisition unit, which is installed at the middle of the rear end of the sprayer to acquire image information of the water-sensitive paper after spraying and send it to the industrial control computer.

[0021] As a further technical solution, the online detection unit for droplet deposition effect information includes an industrial control computer. When the industrial control computer determines the presence of water-sensitive paper based on the image acquired by the first image acquisition unit, it triggers a timer. After a time T, the industrial control computer acquires an image of the water-sensitive paper after spraying based on the second image acquisition unit. L is the distance between the first image acquisition unit and the second image acquisition unit, T = L / v, v is the speed of the boom sprayer, and T is the time for acquiring droplet deposition effect information.

[0022] Secondly, an online detection method for the droplet deposition effect of a boom sprayer is disclosed, including:

[0023] Ensure that the boom sprayer maintains its travel trajectory during normal operation;

[0024] The position of the water-sensitive paper before spraying to detect the droplet deposition effect was obtained;

[0025] Measure the travel speed of the boom sprayer;

[0026] The acquired image information of the water-sensitive paper after spraying;

[0027] Based on the acquired position of the water-sensitive paper, the travel speed of the boom sprayer, and the image information of the water-sensitive paper after spraying, information characterizing the droplet deposition effect is obtained through real-time online calculation.

[0028] As a further technical solution, droplet distribution and density data are obtained based on the water-sensitive paper image after spraying, and then the number and volume of droplets in the measurement area and the area ratio occupied by droplets are obtained to calculate the droplet density and droplet coverage.

[0029] As a further technical solution, to ensure that the travel trajectory of the boom sprayer remains unchanged during normal operation, the following are included:

[0030] When the crop touches the single-sided limit switch a set number of times within the set travel distance, the controller determines that the sprayer is deviating from the crop row, and then controls the electro-hydraulic proportional directional valve to make the steering wheel deflect in the opposite direction of the wheel direction signal source. At this time, the steering angle sensor detects the deflection angle and sends the detection signal to the controller. When the deflection angle reaches the set value, the electro-hydraulic proportional directional valve stops operating.

[0031] After the sprayer aligns with the row, if the crop does not touch any limit switch on either side within the set travel distance, the controller sends a signal to the proportional directional valve to return the steering wheel to the correct position, ensuring that the sprayer's travel trajectory remains unchanged.

[0032] The above one or more technical solutions have the following beneficial effects:

[0033] This invention addresses the challenges of maintaining a constant travel trajectory for the boom sprayer during normal operation, while utilizing a water-sensitive paper positioning unit to determine the position of the water-sensitive paper before spraying to detect droplet deposition. It also employs a boom sprayer speed measurement unit to measure the sprayer's speed, a droplet deposition effect information acquisition unit to obtain images of the water-sensitive paper after spraying, and an online droplet deposition effect detection unit to obtain information characterizing the droplet deposition effect. This allows for real-time acquisition of droplet density and droplet coverage information during the plant protection machine's operation, overcoming the current problems of time-consuming and complex field-to-laboratory processing of droplet deposition effects from boom sprayers. This provides a strong basis for real-time adjustment of spraying parameters and intelligent plant protection.

[0034] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0035] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0036] Figure 1 This is a system block diagram of the online detection system for spray droplet deposition effect of a boom sprayer provided in this invention patent;

[0037] Figure 2 This is a system schematic diagram of the online detection system for spray droplet deposition effect of a boom sprayer provided in this invention patent;

[0038] Figure 3 Flowchart illustrating the implementation process of the online detection system for droplet deposition effect of a boom sprayer provided in this invention patent;

[0039] In the diagram, 1 is water-sensitive paper, 2 is a high-speed positioning camera, 3 is a spray bar, and 4 is a high-speed data acquisition camera. Detailed Implementation

[0040] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0041] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0042] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0043] Example 1

[0044] See appendix Figure 1 As shown in the figure, this embodiment discloses an online detection system for the spray droplet deposition effect of a boom sprayer, including: a boom sprayer travel trajectory maintenance control unit, a water-sensitive paper positioning unit, a boom sprayer travel speed measurement unit, a droplet deposition effect information acquisition unit, and a droplet deposition effect information online detection unit. Each unit communicates with each other through a CAN bus.

[0045] The aforementioned boom sprayer trajectory maintenance control unit ensures that the boom sprayer's trajectory remains unchanged during normal operation; the water-sensitive paper positioning unit acquires the position of the water-sensitive paper before spraying to detect droplet deposition effects; the boom sprayer speed measurement unit measures the boom sprayer's speed; the droplet deposition effect information acquisition unit acquires the image information of the water-sensitive paper after spraying; and the online droplet deposition effect information detection unit calculates information characterizing the droplet deposition effect in real time based on the acquired water-sensitive paper position, boom sprayer speed, and post-spray image information. This system is highly intelligent, simple in structure, easy to operate, and readily applicable.

[0046] In one implementation example, Figure 2 The diagram shows the system principle of an online detection system for droplet deposition effects of a boom sprayer. The boom sprayer's trajectory maintenance control unit includes limit switches, a steering angle sensor mounted on the travel wheels, a controller, an electromagnetic proportional directional valve mounted on the steering hydraulic circuit, and a steering cylinder. Two limit switches are installed, one on each of the left and right wheels of the sprayer. This control unit ensures the sprayer's trajectory remains constant, facilitating precise positioning of the water-sensitive paper and accurate acquisition of droplet deposition effect information.

[0047] In one implementation example, the water-sensitive paper positioning unit includes a high-speed camera. The high-speed camera is mounted at the center of the front end of the spray boom of the boom sprayer, used to acquire images and detect and identify the water-sensitive paper with droplet deposition effects. Specifically, the high-speed camera transmits the acquired images to an industrial control computer via a CAN bus. Image recognition software installed in the industrial control computer processes the data in real time, and the industrial control computer starts timing upon detecting an image containing water-sensitive paper.

[0048] Among them, the identification of water-sensitive paper in the image, based on the fact that the color of water-sensitive paper is yellow and the size is uniform, can be improved by training with deep learning algorithms.

[0049] In one implementation example, the boom sprayer's travel speed measurement unit includes two speed encoders, each mounted on the axle of the front and rear wheels of the sprayer. The encoders measure the rotational speed of the front and rear wheels and convert this speed into the travel speed of the boom sprayer using the diameter of the wheels. The travel speed measurement unit then transmits the acquired information to an industrial control computer via a CAN bus.

[0050] In one implementation example, the droplet deposition effect information acquisition unit includes a high-speed camera, which is installed in the middle of the rear end of the sprayer to acquire images. The droplet deposition effect information acquisition unit sends the data to the industrial control computer via a CAN bus, and the industrial control computer can extract the droplet deposition information after processing.

[0051] The specific implementation method is as follows: when the water-sensitive paper positioning unit detects the water-sensitive paper, the industrial control computer starts timing. After time T, the high-speed camera of the droplet deposition effect information acquisition unit starts acquiring image information and sends the acquired information to the industrial control computer via the CAN bus. T = L / v, where L is the distance between the positioning high-speed camera and the acquisition camera, v is the travel speed of the spray boom sprayer, and T is the time to acquire droplet deposition effect information. That is, at this time, the industrial control computer just turns on the camera and can acquire the image of the water-sensitive paper after spraying.

[0052] In one implementation example, the online detection unit for droplet deposition effect information includes an industrial control computer. The industrial control computer receives the position information of the water-sensitive paper and the travel speed of the boom sprayer via a CAN bus, accurately calculates the droplet deposition effect acquisition time (T), and acquires images of the water-sensitive paper after spraying. Simultaneously, it uses DepositScan software installed on the industrial control computer to process and analyze the acquired images of the water-sensitive paper after spraying in real time, obtaining information characterizing the droplet deposition effect, such as droplet density and droplet coverage.

[0053] The specific implementation method is as follows: the droplet deposition effect information acquisition unit sends the image of the water-sensitive paper after spraying, acquired by the high-speed camera, to the online detection unit of droplet deposition effect information via the CAN bus in image format; the water-sensitive paper image after spraying is scanned by DepositScan software, and then the number, size, area, volume, and distribution data of droplets on the water-sensitive paper are processed and analyzed by the built-in tools of DepositScan software or third-party software (such as Excel, MATLAB, etc.). Specifically, based on the scanning of DepositScan software, the number and diameter of droplets can be directly obtained, and then the area of ​​a single droplet can be calculated. Since droplets are usually considered to be spherical, the volume of droplets can be calculated. Based on the number and volume of droplets in the measurement area and the proportion of area occupied by droplets, the density and coverage of droplets can be calculated.

[0054] Specifically, droplet density refers to the number of droplets deposited per unit area, usually expressed as the number of droplets covering each square centimeter on the crop surface. Water-sensitive paper is typically 25 mm * 76 mm in size. Assuming the area of ​​the water-sensitive paper is S square centimeters and the number of droplets on the water-sensitive paper is N, then the droplet density is N / S, with the unit being droplets per square centimeter.

[0055] Droplet coverage refers to the proportion of the target surface covered by droplets during a spraying operation. Assuming the area of ​​the water-sensitive paper is S square centimeters and the number of droplets on the paper is N, the area of ​​the nth droplet... Then the area of ​​all the droplets on the water-sensitive paper is If the unit is square centimeters, then the droplet coverage rate on the water-sensitive paper is A / S*100%, with the unit being _____.

[0056] Based on the above description, in this embodiment, the boom sprayer trajectory maintenance control unit, based on limit switches and steering angle sensors, maintains and controls the boom sprayer's trajectory, ensuring accurate positioning of the water-sensitive paper and precise acquisition of droplet deposition effect information. Through the water-sensitive paper positioning unit and the boom sprayer speed measurement unit, the droplet deposition effect information acquisition time is accurately calculated, and the acquired information is sent to the industrial control computer via the CAN bus. The DepositScan software installed on the industrial control computer acquires information characterizing the droplet deposition effect, such as droplet density and droplet coverage, in real time.

[0057] Example 2

[0058] In this embodiment, an online detection method for the droplet deposition effect of a boom sprayer is disclosed, including:

[0059] First, ensure that the boom sprayer maintains its travel trajectory during normal operation;

[0060] Then, the position of the water-sensitive paper before spraying was obtained to detect the droplet deposition effect;

[0061] Measure the travel speed of the boom sprayer;

[0062] The acquired image information of the water-sensitive paper after spraying;

[0063] Based on the acquired position of the water-sensitive paper, the travel speed of the boom sprayer, and the image information of the water-sensitive paper after spraying, information characterizing the droplet deposition effect is obtained through real-time online calculation.

[0064] In one implementation example, droplet distribution and density data are obtained based on the water-sensitive paper image after spraying. Then, the number and volume of droplets in the measurement area and the area ratio occupied by droplets are obtained, and the droplet density and droplet coverage are calculated.

[0065] Ensuring that the boom sprayer maintains its trajectory during normal operation includes:

[0066] When the crop touches the single-side limit switch a set number of times within the set travel distance, the controller determines that the sprayer is deviating from the crop row. It then controls the electro-hydraulic proportional directional valve to make the steering wheel deflect in the opposite direction of the wheel direction signal source. At this time, the steering angle sensor detects the deflection angle and sends the detection signal to the controller. When the deflection angle reaches the set value, the electro-hydraulic proportional directional valve stops operating, completing the sprayer deflection alignment.

[0067] After the sprayer aligns with the row, if the crop does not touch any limit switch on either side within the set travel distance, the controller sends a signal to the proportional directional valve to return the steering wheel to the correct position, ensuring that the sprayer's travel trajectory remains unchanged.

[0068] For the implementation of the online detection system for spray droplet deposition effect of boom sprayer, please refer to the appendix. Figure 3 As shown,

[0069] The implementation process of the online detection system for spray droplet deposition effect of boom sprayer:

[0070] Before operating the boom sprayer, water-sensitive paper 1 is manually placed at a suitable position on the crop. In order to obtain more accurate information on the droplet deposition effect, the water-sensitive paper is generally placed on top of the crop.

[0071] During normal operation, the crops will not touch the limit switches on the sprayer wheels. If the crops repeatedly touch a single limit switch within the set travel distance, the controller determines that the sprayer has deviated from the crop row. It then controls the electro-hydraulic proportional directional valve to cause the steering wheel to deflect in the opposite direction of the wheel direction signal. At this time, the steering angle sensor detects the deflection angle and sends a signal to the controller. When the deflection angle reaches the specified (set) value, the electro-hydraulic proportional directional valve stops operating. After the sprayer has aligned itself with the crop row, if the crops do not touch any limit switches on either side within the specified travel distance, the controller sends a signal to the proportional directional valve to return the steering wheel to the correct position, ensuring the sprayer's travel trajectory remains unchanged. This guarantees accurate positioning of the water-sensitive paper and accurate collection of droplet deposition information.

[0072] When the high-speed camera 2, positioned by the water-sensitive paper positioning unit at the front center of the spray boom 3 installed on the boom sprayer, detects the water-sensitive paper, it starts timing. The industrial control computer calculates the time for collecting droplet deposition information based on the water-sensitive paper detection time and the speed of the sprayer. After the time is reached, the high-speed camera 4 of the droplet deposition effect information acquisition unit starts working to acquire image information after spraying. The above information is sent to the industrial control computer via the CAN bus. The DepositScan software installed on the industrial control computer acquires information characterizing the droplet deposition effect, such as droplet density and droplet coverage, in real time.

[0073] The above process continues in a loop until the spraying operation is completed.

[0074] This embodiment of the sub-technology solution enables real-time monitoring of droplet density, droplet coverage, and other characterizing values ​​of droplet deposition effect during boom sprayer operation. It overcomes the current problems of time-consuming and complex field-to-laboratory processing of droplet deposition effect data, providing a strong basis for real-time adjustment of spraying parameters and intelligent plant protection. Furthermore, the system is highly intelligent, simple in structure, easy to operate, and readily applicable.

[0075] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0076] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An online detection system for the droplet deposition effect of a boom sprayer, characterized in that, include: The boom sprayer travel trajectory maintenance control unit is used to ensure that the travel trajectory of the boom sprayer remains unchanged during normal operation; The water-sensitive paper positioning unit is used to obtain the position of the water-sensitive paper before spraying to detect the droplet deposition effect; The water-sensitive paper positioning unit includes a first image acquisition unit, which is installed at the middle of the front end of the spray bar of the spray bar sprayer. The boom sprayer travel speed measurement unit is used to measure the travel speed of the boom sprayer. The boom sprayer travel speed measurement unit includes a speed encoder, which is installed at a set position on the sprayer wheels and is used to measure the rotational speed of the front and rear wheels of the boom sprayer. The droplet deposition effect information acquisition unit is used to acquire image information of the water-sensitive paper after spraying; The droplet deposition effect information acquisition unit includes a second image acquisition unit, which is installed at the middle of the rear end of the sprayer. The online detection unit for droplet deposition effect information calculates information characterizing the droplet deposition effect in real time based on the acquired position of the water-sensitive paper, the travel speed of the boom sprayer, and the image information of the water-sensitive paper after spraying. The online detection unit for droplet deposition effect information includes an industrial control computer. When the industrial control computer determines the presence of water-sensitive paper based on the image acquired by the first image acquisition unit, it triggers a timer. After a time T, the industrial control computer acquires an image of the water-sensitive paper after spraying based on the second image acquisition unit. L is the distance between the first image acquisition unit and the second image acquisition unit, T = L / v, v is the speed of the boom sprayer, and T is the time to acquire droplet deposition effect information.

2. The online detection system for spray droplet deposition effect of a boom sprayer as described in claim 1, characterized in that, Under the premise that the travel trajectory of the boom sprayer remains unchanged during normal operation, the water-sensitive paper positioning unit, the boom sprayer travel speed measurement unit, the droplet deposition effect information acquisition unit, and the droplet deposition effect information online detection unit shall operate normally.

3. The online detection system for spray droplet deposition effect of a boom sprayer as described in claim 1, characterized in that, The boom sprayer trajectory maintenance control unit includes: The system includes a limit switch, a steering angle sensor, a controller, an electromagnetic proportional directional valve, and a steering cylinder. The limit switch is installed on the left and right wheels of the boom sprayer. Both the limit switch and the steering angle sensor are connected to the controller to transmit the collected information. The controller is connected to the steering cylinder via the electromagnetic proportional directional valve, and the steering cylinder is used to control the movement of the steering wheels.

4. The online detection system for spray droplet deposition effect of a boom sprayer as described in claim 1, characterized in that, The first image acquisition unit transmits the acquired image to the industrial control computer via a bus, and the industrial control computer determines the position of the water-sensitive paper based on the acquired image.

5. The online detection system for spray droplet deposition effect of a boom sprayer as described in claim 1, characterized in that, The speed encoder is used to measure the rotational speed of the front and rear wheels of the boom sprayer and sends the acquired information to the industrial control computer via a bus.

6. The online detection system for spray droplet deposition effect of a boom sprayer as described in claim 1, characterized in that, The second image acquisition unit acquires image information of the water-sensitive paper after spraying and sends it to the industrial control computer.

7. An online detection method for the spray droplet deposition effect of a boom sprayer, applied to an online detection system for the spray droplet deposition effect of a boom sprayer as described in any one of claims 1-6, characterized in that, include: Ensure that the boom sprayer maintains its travel trajectory during normal operation; The position of the water-sensitive paper before spraying to detect the droplet deposition effect was obtained; Measure the travel speed of the boom sprayer; The acquired image information of the water-sensitive paper after spraying; Based on the acquired position of the water-sensitive paper, the travel speed of the boom sprayer, and the image information of the water-sensitive paper after spraying, information characterizing the droplet deposition effect is obtained through real-time online calculation.

8. The online detection method for spray droplet deposition effect of a boom sprayer as described in claim 7, characterized in that, Based on the water-sensitive paper image after spraying, droplet distribution and density data are obtained. Then, the number and volume of droplets in the measurement area and the area occupied by droplets are obtained, and the droplet density and droplet coverage are calculated.

9. The online detection method for spray droplet deposition effect of a boom sprayer as described in claim 7, characterized in that, Ensuring that the boom sprayer maintains its trajectory during normal operation includes: When the crop touches the single-sided limit switch a set number of times within the set travel distance, the controller determines that the sprayer is deviating from the crop row, and then controls the electro-hydraulic proportional directional valve to make the steering wheel deflect in the opposite direction of the wheel direction signal source. At this time, the steering angle sensor detects the deflection angle and sends the detection signal to the controller. When the deflection angle reaches the set value, the electro-hydraulic proportional directional valve stops operating. After the sprayer aligns with the row, if the crop does not touch any limit switch on either side within the set travel distance, the controller sends a signal to the proportional directional valve to return the steering wheel to the correct position, ensuring that the sprayer's travel trajectory remains unchanged.

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