GB2605844A

GB2605844A - Agricultural boom height control system and method

Info

Publication number: GB2605844A
Application number: GB2105475.4A
Authority: GB
Inventors: Walters Nicolas; Davies Susan
Original assignee: Patchwork Tech Ltd
Current assignee: Patchwork Tech Ltd
Priority date: 2021-04-16
Filing date: 2021-04-16
Publication date: 2022-10-19
Also published as: GB202105475D0

Abstract

A control system 100 for controlling a reconfiguration of an agricultural sprayer boom 130 in dependence of a field topography and/or crop canopy height, and a method of control of a sprayer arm using the said control system comprises of providing, (i) a satellite navigation based positioning control subsystem 120 to produce field topography data (220, Fig 2) at a local field location, (ii) one or more distance measurement sensors 150 for sensing boom height and generating boom height data (250, Fig 2), (iii) one or more inertial measurement sensors 140 mounted on the boom for sensing boom geometry and generating boom geometry data (240, Fig 2) and (iv) a prediction subsystem adapted to receive and process the local field location topography data, the boom height data and the boom geometry data and generate required configuration parameters for the required boom height data and the required boom geometry data at a remote field location.

Description

AGRICULTURAL BOOM HEIGHT CONTROL SYSTEM AND METHOD

The present invention relates generally to an automated machine control system and specifically to an agricultural spray boom height control system and method.

Precision agriculture (PA), satellite farming or site-specific crop management (SSCM) has been made possible by satellite navigation systems such as Global Positioning System and Global Navigation Satellite System (GPS/GNSS), and local sensor data. These technologies enable the coupling of real-time data collection with accurate position information, used for farm planning, field mapping, soil sampling, tractor guidance, crop scouting, variable rate applications, and yield mapping.

During agricultural spraying, a chemical is applied to the soil via a wide boom of nozzles which is a series of metal arms that is pulled behind the sprayer vehicle. The crop grows at different stages and therefore the variable crop height together with undulations in fields creates a difficult task for the vehicle driver to keep the boom at a set height above the crop and ensure a uniform deposition of chemical across the crop.

Existing systems work on a reactive basis, determining the current location at a given moment in time and subsequently responding. If the changes required are substantial this can cause fast movement of what is typically an unstable part of the sprayer vehicle. This fast response can make a vehicle jerk resulting in incorrect spraying and in worst case scenarios the boom can either damage crops or itself be damaged by hitting the ground.

The proposed invention improves on those existing systems, such as disclosed in US20140277676A1, by including a multi sensor system which is necessary to provide sufficient information, at a speed capable of allowing decisions to be made in advance of the required movement. The system may utilise ultra-sonic sensors to sense crop height and gyroscopes on each boom arm (or moving parts of the sprayer) to continuously monitor the orientation of the boom. Moreover, the input of a real time satellite positioning of the sprayer and a known surface map of the terrain enables a novel prediction algorithm to conduct smooth movements of the boom in anticipation of changes in elevation.

The fusion of sensor input and satellite information feeds into a prediction algorithm and broadly follow the steps: 1. Read GPS, speed and heading of a vehicle with sprayer boom, then calculate a projected vehicle position; 2. Check the projected position against the 3d ground model to establish a projected boom position; 3. Compare, using angle and height sensors, the current position of the boom and determine if movement is required; and 4. Send signals to move the boom based on the required upcoming changes.

According to a first aspect of the present invention, a control system for controlling a reconfiguration of an agricultural sprayer boom in dependence of a field topography and/or crop canopy height, the control system comprising: a satellite navigation based positioning control subsystem to produce field topography data at a local field location; one or more distance measurement sensors for sensing boom height and generating boom height data; one or more inertial measurement sensors mounted on the boom for sensing boom geometry and generating boom geometry data; a prediction subsystem adapted to receive and process the local field location topography data, the boom height data, and the boom geometry data, and generate required configuration parameters for the required boom height data and the required boom geometry data at a remote field location.

In an embodiment, the remote field location is disposed on a trajectory path from the local field location.

In an embodiment, the control system further comprises stored field topography data, wherein the stored field topography data is also received by the prediction subsystem to generate required configuration parameters for the boom.

In an embodiment, the prediction subsystem combines the stored field topography data and current field topography data to calculate a height correction parameter for the boom.

In an embodiment, the prediction subsystem combines the current field topography data and boom geometry data to calculate projected configuration parameters for the boom.

In an embodiment, the prediction subsystem combines the height correction parameters and projected configuration parameters to calculate future configuration parameters for the sprayer boom.

In an embodiment, the prediction subsystem combines the boom geometry data and boom height data to calculate the current configuration parameters of the boom.

In an embodiment, the prediction subsystem compares the current configuration parameters and future configuration parameters to calculate required configuration parameters of the boom.

In an embodiment, the required configuration parameters for the sprayer boom are output as controls to reconfigure the height and geometry of the sprayer boom.

In an embodiment, the sprayer boom comprises one or more moving parts and an inertial measurement sensors is mounted on each moving part.

In an embodiment, the inertial measurement sensors comprises: a 9-axis sensor; and the sprayer boom geometry data comprises: 3d linear acceleration; 3d angle rate; and, 3d magnetic position data; of the sprayer boom.

In an embodiment, a distance measurement unit is mounted on each moving part.

In an embodiment, the sprayer boom height data comprises; height from the crop canopy and/or height from the field surface.

According to a second aspect of the present invention, there is provided a method of controlling a reconfiguration of an agricultural sprayer boom in dependence of a field topography and/or crop canopy height, the method comprising the steps: producing field topography data at a local field location from a satellite navigation based positioning control subsystem; producing sprayer boom height data from one or more distance measurement sensors; producing sprayer boom geometry data from one or more inertial measurement unit sensors mounted on the sprayer boom; processing the local field location topography data, sprayer boom height data and sprayer boom geometry data with a prediction subsystem; and calculating required configuration parameters for the required boom height data and the required boom geometry data at a remote field location.

In an embodiment, the method includes the further step of receiving stored field topography data, to be processed with the prediction subsystem.

In an embodiment, the method includes the further step of outputting the positioning parameters as controls to reconfigure the height and geometry of the sprayer boom.

The invention may be produced in various ways and embodiments thereof will now be described, by way of example only, reference being made to the accompanying drawings, in which:-Figure 1 illustrates a control system according to an embodiment of the present invention, for controlling the position of an agricultural sprayer boom relative to a field surface to implement the method according to the present invention; Figure 2 is a data flow diagram illustrating the path of information within a control system according to an embodiment of the present invention; and, Figure 3 is a flow diagram illustrating the steps of a method according to an embodiment of the present invention.

Figure 1 illustrates a control system (100) according to an embodiment of the present invention for controlling the position of an agricultural sprayer boom (130) relative to a crop (C) and field surface (G). The control system is communicatively coupled to a vehicle (190) which is either integral with, mounts or tows a sprayer boom around the area of farming. This vehicle can be either a conventional agricultural tractor or a combined self-propelled vehicle which combines the sprayer boom into one vehicle. The sprayer boom (130) consists of a large tank (not shown) for holding chemical to be sprayed and a pump mechanism (not shown) in communication with the control system for spraying at the required flow rate, wherein the liquid is sent to the sprayer boom via sprayer hoses (not shown). The sprayer boom is the main part of the vehicle that consists of one or more movable components (130L, 130R). The sprayer boom is usually behind the vehicle and is required to fold to allow for road transport. The boom is suspended and comprises a plurality of boom sections articulately coupled via articulation points which allow the boom to articulate along a length thereof in dependence of the topography of the filed surface and crop canopy. The sprayer boom may include: a lift frame (not shown) controlled by a hydraulic ram (not shown) which lifts the boom up and down above the ground; a tilt frame (not shown) which tilts the whole boom using a hydraulic ram (not shown); and a back frame (not shown) from which individual movable sections are suspended. In the illustrated embodiment, the back frame comprises a central part of the sprayer boom and is connected to the vehicle by the lift frame and the tilt frame. The sprayer boom can be available in various sizes from 12m to 48m. Each boom is split into sections which have individual electric control valves to open or close the nozzles to control the flow of liquid. The sprayer boom is able to fold for storage, tilt and lift. A graphical user interface (GUI) or user interface can be located in view of the operator in the cab of the vehicle. A pictorial visualisation of the current status of the boom can be provided to ensure feedback on the status of all sensors and also the current geometry of the sprayer boom. The movable parts of the boom are possible with the use of electric solenoid hydraulic rams, this allows the flow of hydraulic fluid based on the decision of the control system, this will allow movement in multiple directions for each moveable part.

A central processing unit, CPU (110) receives data from all connected sensors and using sensor fusion (the process of combining sensory data or data derived from disparate sources such that the resulting information has less uncertainty than would be possible when these sources were used individually) combines the data based on current position, heading, and angle, of all movable components and the future requirements, thereby providing decision making for moving of the moveable components of the sprayer boom. A communication network (112) can be utilised, commonly known as Controller Area Network (CAN) for transmitting sensor messages at high speed around the vehicle. This will allow for an unlimited number of sensors and control systems.

A geographic information system or mapping system (120) can be located in the farm office on a computer or via a connected cloud internet service and is used to process the map data from the field and to build an elevation map (210) to send to all vehicles as part of the CPU sensor fusion functionality to predict the requirements for the boom geometry. The topographic 3d map or surface map can contain position and elevation data recorded by the GNSS receiver as the field is navigated in previous operations and processed using the farm computer. The outside of the field can be recorded using a GNSS receiver at set intervals and the data combined to create the field perimeter, this ensures the boundary of the maps is enclosed within a selected area. This perimeter is also usable to classify the data to ensure all data points are not just geo-referenced but are traceable to a specific plot of land. GNSS receivers can provide altitude measurements as well as position data. All data recorded with each plot of land can be collected over subsequent runs across a field to enable the mapping of each plot of land for altitude readings. An elevation/topographic map can be prepared from the separate initial survey of the field using the office mapping software for each field and transferred to the control system (110) via either removable media or transferred directly from the cloud storage. The elevation data will be created from the altitude readings. The elevation map will be corrected in real-time with current altitude and position readings, reducing the need for survey grade/real-time kinematic GNSS receivers to be used.

During the crop spraying operation, the current GNSS readings (220) are compared to the stored topographic map (210) and corrections can be made to provide an accurate height based on current position. This reduces the need for higher accuracy GPS (RTK). This operation is so called real-time height correction explained with respect to the dataflow and method (Figures 2 and 3). An accurate GNSS receiver can be used to ensure precise, repeatable location and altitude measurements whilst moving across the field. Only a single receiver would be required and can be located within the vehicle and the locations of each of the sensors calculated by measurements between them. This increases the practicality of the system and reduces costs, but it is necessary to ensure the height readings are accurate using comparison and correction techniques via the sensor fusion.

Inertial measurement units (140) such as a single chip 9-axis sensor are provided on the boom and utilised to provide 3d linear acceleration, 3d angle rate and 3d magnetic position (240) (a 9-axis absolute orientation sensor is a combination of a 3-axis acceleration sensor, a 3-axis gyroscope and a 3-axis geomagnetic sensor). This will provide both the current angle and shape of the boom, additionally also the rate of movement during change, vehicle movement and vehicle turning. The addition of a digital compass via the magnetic position provides accurate heading data and allow for comparison of the angle of each moving component compared to the desired shape required.

Distance measurement sensors (150) such as ultrasonic sensors can be placed at each end of the sprayer boom and also at strategic places along the boom to enable the sensing of the crop (C) rather than the ground (G). This measurement can be utilised to correct the target height based on the current crop height at that location. The height sensor can provide actual height readings in mm in real-time. The height readings are provided at intervals across the sprayer boom to provide measurements to be used to provide movement. If the crop canopy is not completely closed, then two readings will be available, one from the ground (G) and the second from the crop canopy (C). The software methodology within the control system (100) can be used to differentiate and provide both readings if available for the boom shape correction.

Figure 2 is a data flow diagram showing how data is processed within a system based on inputs and outputs from the sensors and the processes that transform the data to provide for the improved positioning and function of the boom. As described above the data inputs to the control system (100) are the topographic map (210), the current GNSS position and height above sea level (220), IMU or 9 axis sensor readings (240) and height sensor readings (250).

The stored elevation/topographic map (210) is fused with the current GNSS position data (220) to perform real time height correction (P1) calculations. The implementing method/software is required to ensure the most accurate height calculation for both current location and projected future location. This is required to enable the use of lower cost GNSS receivers.

The current GNSS position data (220) is fused with the inertial measurement unit readings (240) which can include 9 degrees of freedom measurements, to determine a projected position (P2) of the sprayer boom. The future requirement (P3) of the sprayer boom shape can then be determined using the current position (220), heading (240) and projected position (P2) at a set distance together with the height correction (P1). This is repeated at set intervals across the sprayer boom, which will provide a series of corrected height readings (P1) for the future location of the moveable parts (130L,130R) of the sprayer boom. These readings will enable the algorithm to decide on the required shape of the sprayer boom for the future location before reaching the location. The difference between the ground and crop canopy height can also be taken into account to cater for differences in thickness and height of crop.

The current boom shape (P4) is determined by the inertial measurement unit readings (240) and the height sensor readings (250). To change from the current boom shape (P4) to the future boom shape (P3) the movement required per moving part/boom section (P5) is required. The control system (100) is arranged to calculate the required movement of the current boom shape to achieve the future boom shape. This provides movement requirements in advance of a projected location allowing for smoother transition between boom configurations, rather than rapid jerky movements which cause destabilisation of the boom shape. This can be output as electro-hydraulic controls (290) or other suitable control output to the configure the boom geometry.

Referring to Figure 3 of the drawings, there is illustrated a flow chart sequencing the steps of a method (300) according to an embodiment of the present invention, comprising the steps: producing field topography data at a local field location from a satellite navigation based positioning control subsystem (310); producing sprayer boom height data from one or more distance measurement sensors (320); producing sprayer boom geometry data from one or more inertial measurement unit sensors mounted on the sprayer boom (330); processing the current field surface data, sprayer boom height data and sprayer boom geometry data with a prediction subsystem (340); and calculating positioning parameters for the sprayer boom. The method may include the further step of receiving stored field topography data (210), to be processed with the prediction subsystem. The method may include the further step of outputting the positioning parameters as controls to reconfigure the shape and height of the sprayer boom (350).

The method predicts the required orientation of the sprayer boom arms to best fit the topography of the field at a projected location, using a prediction algorithm working from the topographic map and the current position and elevation provided by the GNSS receiver. Based on the ultra-sonic sensors and the tilt sensors, the software is arranged to control a change in the height and shape of the boom in advance to ensure a smoother transition between boom configurations. To accurately calculate the position, configuration and orientation of the boom as it moves across the field, a rear offset calculation is required for both towed and self-propelled sprayers. The height of the middle of the back frame above the ground, is calculated from the lift frame angle, which pivots up and down to provide an increase or decrease in the height of the middle of the boom. The height of each of the boom sections is then calculated based on the boom angle difference to the vehicle and the programmed size and pivot location. The GNSS position and heading is then used to calculate the location on the elevation map and predict where the boom will be in the time it takes to make a movement change e.g. 1 second whilst travelling across the field at speeds up to 30km/h. The elevation for each section of the boom is also calculated based on the elevation map. The height of the crop is sensed using an ultra-sonic sensor and is used to provide small changes required based on inconsistent crop height, which can also be variable depending on the elevation of the field. This process will provide small changes to add to the calculation above for the predicted height of the boom in the future.

Advantageously the claimed invention can utilise the sensor fusion with the use of topography mapping to enable true "look-ahead" prediction. The use of height sensors to measure both height above ground and height above crop will allow for changes in crop canopy variance. The use of low cost GNSS to calculate real-time height correction reduces the barrier to entry and reduces the price point. Additionally, this also allows for the same GNSS system to be used to survey and spray. Using the 9-axis sensors to provide accurate boom shape data, on current shape and required shape, enables the movement required to attain desired the required shape to be calculated. The combination of sensors provides sufficient information, quickly enough to allow decisions to be made in advance of the required movement. The predictive capabilities of the system would allow for much smoother movements of the boom giving each moving part time to acquire the correct shape and configuration. Sensing both the canopy and the ground allows for the system to adapt at each moving part/boom section to the height of the crop at a particular location and also relay that information to other systems to increase or decrease the applied chemical dose e.g. liquid fertiliser or grow regulators in that area.

Claims

CLAIMS1. A control system (100) for controlling a reconfiguration of an agricultural sprayer boom in dependence of a field topography and/or crop canopy height, the control system comprising: a satellite navigation based positioning control subsystem (120) to produce field topography data (220) at a local field location; one or more distance measurement sensors (150) for sensing boom height and generating boom height data (250); one or more inertial measurement sensors (140) mounted on the boom for sensing boom geometry and generating boom geometry data (240); a prediction subsystem adapted to receive and process the local field location topography data (220), the boom height data (250), and the boom geometry data (240), and generate required configuration parameters (P5) for the required boom height data and the required boom geometry data at a remote field location.
2. The control system according to claim 1, wherein the remote field location is disposed on a trajectory path from the local field location.
3. The control system according to claim 1, further comprising stored field topography data (210), wherein the stored field topography data is also received by the prediction subsystem to generate required configuration parameters (PS) for the boom.
4. The control system according to claim 3, wherein the prediction subsystem combines the stored field topography data (210) and current field topography data (220) to calculate a height correction parameter (P1) for the boom.
5. The control system according to claim 4, wherein the prediction subsystem combines the current field topography data (220) and boom geometry data (240) to calculate projected configuration parameters (P2) for the boom.
6. The control system according to claim 5, wherein the prediction subsystem combines the height correction parameters (P1) and projected configuration parameters (P2) to calculate future configuration parameters (P3) for the sprayer boom.
7. The control system according to claim 6, wherein the prediction subsystem combines the boom geometry data (240) and boom height data (250) to calculate the current configuration parameters (P4) of the boom.
8. The control system according to claim 7, wherein the prediction subsystem compares the current configuration parameters (P4) and future configuration parameters (P3) to calculate required configuration parameters (P5) of the boom.
9. The control system according to claim 8, wherein the required configuration parameters (P5) for the sprayer boom are output as controls to reconfigure the height and geometry of the sprayer boom.
10. The control system according to any previous claim, wherein the sprayer boom comprises one or more moving parts and an inertial measurement sensors is mounted on each moving part.
11. The control system according to any previous claim, wherein the inertial measurement sensors (140) comprises: a 9-axis sensor; and the sprayer boom geometry data (240) comprises: 3d linear acceleration; 3d angle rate; and, 3d magnetic position data; of the sprayer boom.
12. The control system according to claim 10 or 11, wherein a distance measurement unit is mounted on each moving part.
13. The control system according to any previous claim, wherein the sprayer boom height data (250) comprises; height from the crop canopy and/or height from the field surface.
14. A method (300) of controlling a reconfiguration of an agricultural sprayer boom in dependence of a field topography and/or crop canopy height, the method comprising the steps: producing field topography data (220) at a local field location from a satellite navigation based positioning control subsystem (120); producing sprayer boom height data (250) from one or more distance measurement sensors (150); producing sprayer boom geometry data (240) from one or more inertial measurement unit sensors (140) mounted on the sprayer boom; processing the local field location topography data (220), sprayer boom height data (250) and sprayer boom geometry data (240) with a prediction subsystem; and calculating required configuration parameters (P5) for the required boom height data and the required boom geometry data at a remote field location.
15. The method according to claim 14, including the further step of receiving stored field topography data (210), to be processed with the prediction subsystem.
16. The method according to claim 15, including the further step of outputting the positioning parameters (P5) as controls (290) to reconfigure the height and geometry of the sprayer boom.