Agricultural machine steering control method, device and equipment and medium

Abstract

The invention discloses an agricultural machine steering control method, device and equipment and a medium, and belongs to the technical field of agricultural machine control. The method comprises the following steps: when a target agricultural machine performs harvesting operation along a first center line to a first vertex on the boundary of a first operation line, determining a second vertex in a second operation line; determining a first circumference according to the second vertex and the minimum turning radius of the target agricultural machine; the first circumference and the second center line are tangent to the second vertex; selecting a first intersection point in the first circumference, and generating a first path from the first vertex to the first intersection point; and according to the first path and the first circumference, controlling the target agricultural machine to steer and run to a second vertex. According to the scheme, the forward and backward states of the vehicle are changed only at the first intersection point, and the vehicle goes backward through the first path and then goes forward through the first circumference, so that the requirement for the field turning space can be reduced as much as possible, and meanwhile, the efficiency and reliability of automatic driving are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of path planning technology, and in particular to a method, device, equipment and medium for controlling the steering of agricultural machinery. Background Technology

[0002] With the development of agricultural machinery automation, a large number of agricultural operations can now be carried out by machinery. For example, after the crops are mature, operators can quickly harvest them by operating large cotton harvesters and combine harvesters.

[0003] Most large agricultural machinery still relies on manual operation by the driver, especially when turning around at the edge of the field after harvesting a row of crops. Drivers need to estimate the turning radius of the machinery and the available space at the edge of the harvested area based on experience to manually perform the turning maneuver. While more and more agricultural machinery has added automatic navigation functions with advancements in equipment, most still rely on the driver's experience to manually plan classic U-shaped, Ω-shaped, or fishtail-shaped trajectories for turns.

[0004] However, the above-mentioned turning trajectory requires a large turning space at the edge of the field. If the turning space at the edge of the field is small, it is necessary to switch between forward and backward multiple times, which cannot simultaneously meet the efficiency and reliability of turning during the automatic driving of agricultural machinery. Summary of the Invention

[0005] Therefore, it is necessary to provide a method, device, equipment, and medium for controlling the steering of agricultural machinery to address the above problems, thereby improving the efficiency and reliability of automatic steering of agricultural machinery.

[0006] This application provides a method for steering control of agricultural machinery, the method comprising: When the target agricultural machinery harvests along the first center line to the first vertex on the boundary of the first work row, the second vertex in the second work row is determined; the second vertex is the intersection of the second center line in the second work row and the boundary of the second work row; the second center line is parallel to the first center line; the first work row and the second work row are adjacent and parallel work rows in the target plot; The first circumference is determined based on the second vertex and the minimum turning radius of the target agricultural machinery; the first circumference is tangent to the second centerline at the second vertex; Select a first intersection point within the first circle and generate a first path from the first vertex to the first intersection point; the first intersection point is located within the first job row; Based on the first path and the first circle, control the target agricultural machinery to turn and run to the second vertex.

[0007] In one optional implementation, selecting the first intersection point within the first circumference includes: Obtain the boundary of the target land parcel; Determine whether the first circle intersects with the boundary of the target plot; If the first circle does not intersect with the boundary of the target plot, then the first intersection point is selected within the first circle.

[0008] In one optional implementation, selecting the first intersection point within the first circumference includes: The intersection of the boundary line between the first work line and the second work line and the first circumference is defined as the first endpoint; The second circumference is determined based on the position of the first vertex and the minimum turning radius of the target agricultural machinery; the second circumference is tangent to the first centerline at the first vertex; The intersection of the second circumference and the first circumference within the first work row is taken as the second endpoint; In the first arc segment formed by the first endpoint and the second endpoint, select the first intersection point.

[0009] In one alternative implementation, the first intersection point is the second endpoint of the first arc segment.

[0010] In one optional implementation, controlling the target agricultural machinery to turn and move to the second vertex according to the first path and the first circumference includes: The real-time motion state of the target agricultural machinery is obtained; the real-time motion state includes the real-time position, real-time speed, and real-time steering angle of the target agricultural machinery. The real-time error of the target agricultural machine is obtained based on its real-time motion state, the first path, and the first circumference; the real-time error includes lateral error and heading error. Calculate the feedback control quantity based on the lateral error and the heading error; The real-time speed and real-time steering angle of the target agricultural machinery are controlled based on the feedback control quantity.

[0011] In one optional implementation, controlling the real-time speed and real-time steering angle of the target agricultural machinery based on the feedback control quantity includes: Obtain the feedforward correction amount corresponding to the target agricultural machinery; Based on the feedback correction amount and the feedforward correction amount, the real-time control quantity of the target agricultural machinery is obtained; The real-time speed and real-time steering angle of the target agricultural machinery are controlled according to the real-time control quantity.

[0012] In an optional implementation, the method further includes: Obtain the tracking error of the target agricultural machinery from the first vertex to the second vertex; The feedforward error is updated based on the tracking error; The updated feedforward error is used to generate the real-time control quantity when the target agricultural machinery moves from the second vertex to the starting point of the harvesting operation in the third work row.

[0013] This application also provides a steering control device for agricultural machinery, the device comprising: The location acquisition module is used to determine the second vertex in the second work row when the target agricultural machinery harvests along the first center line to the first vertex on the boundary of the first work row; the second vertex is the intersection of the second center line in the second work row and the boundary of the second work row; the second center line is parallel to the first center line; the first work row and the second work row are adjacent and parallel work rows in the target plot; A circumference determination module is used to determine a first circumference based on the second vertex and the minimum turning radius of the target agricultural machinery; the first circumference is tangent to the second centerline at the second vertex; The path generation module is used to select a first intersection point within the first circle and generate a first path from the first vertex to the first intersection point; the first intersection point is located within the first work row; The agricultural machinery control module is used to control the target agricultural machinery to turn and run to the second vertex according to the first path and the first circumference.

[0014] In another aspect, this application also provides an electronic device, including: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the above-mentioned agricultural machinery steering control method by executing the computer instructions.

[0015] This application also provides a computer-readable storage medium storing at least one instruction, which is loaded and executed by a processor to implement the above-described agricultural machinery steering control method.

[0016] Compared with the prior art, the technical solution provided in this application has the following advantages: When the target agricultural machinery is harvesting in the target plot, it can operate continuously along pre-planned parallel work rows. When the target machinery reaches the first vertex of the first work row along the first centerline, it needs to turn to the next work row, starting again from the second vertex. At this point, the target machinery needs to determine the position of the second vertex based on the centerline of the second work row. After obtaining the position of the second vertex, a first circle tangent to the second centerline and at the second vertex can be generated based on this position and the target machinery's minimum turning radius. Then, the target machinery only needs to find a drivable first path in the first work row and reach the first intersection point formed by the first path and the first circle. It can then reverse along the first path to the first intersection point and, along the center of the circle formed by the minimum turning radius, directly reach the second vertex to begin harvesting in the second work row. This scheme only changes the vehicle's forward and reverse state at the first intersection point, and by reversing along the first path and then moving forward along the first circle, it minimizes the need for turning space at the edge of the field, while ensuring the efficiency and reliability of autonomous driving. Attached Figure Description

[0017] Figure 1 A reference diagram of a U-shaped turn is shown.

[0018] Figure 2 A reference diagram of a fishtail turn is shown.

[0019] Figure 3 A flowchart of a method for controlling the steering of agricultural machinery according to an embodiment of the present invention is shown.

[0020] Figure 4 A schematic diagram of a first path and a first circumference involved in an embodiment of this application is shown.

[0021] Figure 5 A flowchart illustrating an agricultural machinery steering control method according to an embodiment of the present invention is shown.

[0022] Figure 6 A schematic diagram of a trajectory selection method according to an embodiment of this application is shown.

[0023] Figure 7 A complete flowchart of agricultural machinery control involved in the embodiments of this application is shown.

[0024] Figure 8 This is a schematic diagram of the structure of an agricultural machinery steering control device provided in an embodiment of this application.

[0025] Figure 9 This is a schematic diagram of the structure of an electronic device provided in an optional embodiment of the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0027] Nowadays, the planting and harvesting of a large number of crops are carried out by mechanized operations in large fields. In order to improve the efficiency of mechanized operations in large fields, crops are divided into multiple parallel work rows in the field. Large agricultural machinery (such as large cotton harvesters or combine harvesters) can carry out regular and repetitive harvesting operations in large fields according to the work rows.

[0028] However, when performing repeated harvesting operations along rows, large agricultural machinery faces certain difficulties in turning. For example, there may not be enough space at the edge of the field for large agricultural machinery to turn, and if the large agricultural machinery turns directly, its minimum turning radius may also cause turning difficulties. Therefore, most large agricultural machinery still relies on the driver's experience and uses classic trajectories such as U-shaped, Ω-shaped, and fishtail-shaped turns at the edge of the field, but problems such as poor environmental adaptability (large space requirements for turning at the edge of the field) and multiple turns still exist.

[0029] Figure 1 A reference diagram of a U-shaped turn is shown. (For example...) Figure 1 As shown, when the target agricultural machinery operates in a plot of land, the plot can typically be divided into several parallel working rows. The target agricultural machinery can then perform bow-shaped harvesting operations along these working rows. Figure 1 For example, when the target agricultural machinery travels along the centerline of work row 1 to carry out harvesting operations in work row 1, and finally reaches the end of work row 1, the center point of the target agricultural machinery can be considered as the intersection of the centerline of work row 1 and the boundary of work row 1. At this time, the target agricultural machinery needs to turn to reach work row 2, and make the center point of the target agricultural machinery coincide with the starting point of the centerline of work row 2 and the boundary of work row 2, so that the target agricultural machinery is at the center point of work row 2, which facilitates the harvesting operation in work row 2.

[0030] but Figure 1 As shown, the target agricultural machinery is constrained by the distance to the edge of the target plot during a direct turn. The edge of the target plot is the area within the target plot where no crops are planted and where the target agricultural machinery is permitted to travel. Assume... Figure 1The target agricultural machinery can make a direct U-turn from the end of work row 1 to the beginning of work row 2 (i.e., the maximum radius of curvature in the U-turn is less than the minimum turning radius of the target agricultural machinery). Simply put, if the distance between the center point of the boundary of work row 1 and the center point of the boundary of work row 2 is relatively large, and if the edge of the target plot is D1, then the target agricultural machinery will obviously exceed the range of D1 if it needs to make a U-turn, and in this case, the target agricultural machinery cannot make a U-turn. However, if the edge of the target plot is D2, the target agricultural machinery can make a U-turn normally. Therefore, although the U-turn method allows the target agricultural machinery to directly turn to work row 2 after harvesting work row 1 without changing its direction of movement or other complex operations, it has certain requirements regarding the distance between the edge of the target plot and the distance between the center points of the boundaries of adjacent work rows.

[0031] Since the distance between the boundary center points of adjacent work rows is too close to be able to perform a U-shaped turn, a fishtail turn can be used to reduce the distance restriction between the boundary center points of adjacent work rows. Figure 2 A reference diagram of a fishtail turn is shown. Figure 2 As shown, by using the fishtail turn method, the target agricultural machine first moves in an arc towards the direction of work row 2; then moves forward until the direction of the target agricultural machine is close to perpendicular to the direction of work row 2, then moves backward a certain distance, and then moves forward along a curve that the target agricultural machine can travel to the end of work row 2. That is, the target agricultural machine can turn when the boundary center points of adjacent work rows are relatively close.

[0032] But by Figure 2 and Figure 1 In comparison, the operational complexity is significantly increased. Each turn requires repeated switching between forward and backward, which can cause considerable wear and tear on the machine's mechanical structure over extended periods. Furthermore, the fishtail turn method employed by the target machine places significantly higher demands on the field's edge compared to a U-turn, making it unsuitable for narrower fields.

[0033] Therefore, to overcome the above-mentioned defects, this application also provides a method for controlling the steering of agricultural machinery. Figure 3 A flowchart of a method for controlling the steering of agricultural machinery according to an embodiment of the present invention is shown, as follows: Figure 3 As shown, the method flow includes: Step 301: When the target agricultural machinery harvests along the first center line to the first vertex on the boundary of the first work row, determine the second vertex in the second work row.

[0034] The second vertex is the intersection of the second centerline and the boundary of the second work row; the second centerline is parallel to the first centerline; the first work row and the second work row are adjacent and parallel work rows in the target plot.

[0035] In this embodiment, when the target agricultural machinery performs harvesting operations on the first working row along the first centerline and reaches the first vertex at the boundary of the first working row, this embodiment first determines the starting position of the next working row (the second working row), i.e., the second vertex. In this embodiment: the first centerline is the planned driving route of the first working row; the second centerline is the planned driving route of the second working row; the second centerline is parallel to the first centerline and separated by a preset row spacing; the first working row and the second working row are adjacent and parallel in the field.

[0036] When the target agricultural machinery is detected to have reached the first vertex, the system determines the position of the second vertex based on the pre-defined geometric relationship of the work row. This second vertex is the intersection of the second centerline and the boundary of the second work row, representing the desired position of the target agricultural machinery after completing its turn and entering the second work row. The coordinates of the second vertex can be calculated using a plot map, GNSS positioning, RTK-assisted positioning, or a pre-defined work row model.

[0037] Step 302: Determine the first circumference based on the second vertex and the minimum turning radius of the target agricultural machinery.

[0038] The first circle is tangent to the second center line at the second vertex.

[0039] After determining the second vertex, in order to enable the target agricultural machinery to turn with minimal space requirements, this embodiment constructs a first circumference based on the minimum turning radius of the target agricultural machinery. Specifically, a circle is constructed with the minimum turning radius of the target agricultural machinery as the radius, such that the circle is tangent to the second centerline at the second vertex. The constructed circle is the first circumference.

[0040] The first circle defines the trajectory constraint for the target agricultural machine from entering the turning area to aligning with the second centerline with the minimum turning radius, enabling the vehicle to achieve smooth curved turning within a minimal space and naturally align with the second working row at the end of the circle.

[0041] Step 303: Select a first intersection point within the first circle and generate a first path from the first vertex to the first intersection point; the first intersection point is located within the first work row.

[0042] In order for the target agricultural machinery to enter the turning trajectory of the first circle, this embodiment needs to select a drivable point inside the first working row as the turning connection point, i.e. the first intersection point, and further generate the first path from the first vertex to the first intersection point.

[0043] Optionally, in this embodiment, the second circumference is determined based on the position of the first vertex and the minimum turning radius of the target agricultural machine; then, the intersection of the second circumference and the first circumference within the first working row is taken as the first intersection point. In this case, the first path is essentially the path from the first vertex along the second circumference to the first intersection point. After reaching the first circumference via this first path, the target agricultural machine can directly move to the second vertex along the first circumference, minimizing changes in its motion state (only changes in forward and backward states exist at the first intersection point), and minimizing the turning trajectory of the target agricultural machine, thus improving its turning efficiency.

[0044] Figure 4 A schematic diagram of a first path and a first circumference according to an embodiment of this application is shown. Figure 4 As shown, when the target agricultural machinery operates along the first centerline in the first working row and reaches the end of the first working row, the center point of the target agricultural machinery should coincide with point A, the intersection of the first centerline and the boundary of the first working row. The target agricultural machinery's goal at this time is to move to the adjacent second working row to begin working. In order to ensure the normal operation of the target agricultural machinery, it should move to point D, the intersection of the boundary of the second working row and the second centerline of the second working row. That is to say, the starting point of the target agricultural machinery when performing a turning operation is A, and the ending point is D.

[0045] To achieve the above process, in this embodiment, point D is first used as the tangent point, and the minimum turning radius of the target agricultural machinery is used as the radius of the circle to construct a first circle with center O1 (theoretically, there are two possible positions for O1, but since the first circle is used to determine the turning radius from the first working row to the second working row, the center O1 of the first circle should obviously be one closer to the area where the first working row is located). After constructing the first circle, theoretically, the target agricultural machinery can travel along the first circle from any position on the first circle, eventually reaching point D, and the velocity direction when reaching D is exactly parallel to the second center line, allowing direct commencement of the second working row operation.

[0046] To improve the turning efficiency of the target agricultural machinery, in this embodiment, point A can be used as the tangent point, and the minimum turning radius of the target agricultural machinery can be used as the radius to construct a second circle with center O2, and the center of the second circle is away from the direction of the second working row. The second circle constructed in the above manner intersects the first circle at point B in the first working row (at this time, B can be used as the first intersection point). At this time, the target agricultural machinery moves backward in the AB direction, which is the shortest path for the target agricultural machinery to reach the point on the first circle.

[0047] It is important to note that the target agricultural machinery must reach point B on the first circumference by reversing. The speed of the target machinery upon reaching point B must have a certain angle with the tangent of its speed from B along the first circumference to D. This angle is usually relatively small. The target machinery typically has a rear-wheel steering function; it stops when reversing to point B, turns its rear wheels in place, and then moves forward, thus achieving the path ABD. However, if the target machinery directly reaches the intersection point T of the first and second circumferences outside the first working row by moving forward, the angle between the speed direction from A to T and the speed direction from T along the circumference to D is very large, exceeding the maximum rear wheel turning angle limit. Therefore, T cannot be chosen as the first intersection point.

[0048] And as Figure 4 As shown, during the movement of the target agricultural machinery along the first circumference, as long as the width of the field head area is greater than W, it can pass through as follows: Figure 4 The trajectory shown is used to achieve the turn, and since the trajectory of the first circle satisfies the minimum turning radius of the target agricultural machinery, therefore... Figure 4 The driving trajectory shown can be considered a turning trajectory with almost minimal requirements for the width of the heading area.

[0049] Step 304: Based on the first path and the first circumference, control the target agricultural machinery to turn and run to the second vertex.

[0050] After obtaining the first path and the first circle, the system can control the target agricultural machinery to drive according to the two paths. Specifically, the target agricultural machinery reverses along the first path to the first intersection point, and then switches to forward gear from the first intersection point; then it controls the agricultural machinery to move forward according to the set curve of the first circle; when it moves along the first circle to the second vertex, the target agricultural machinery's orientation is consistent with the second neutral line, so the target agricultural machinery can directly perform the harvesting operation of the next work row along the second center line.

[0051] The above solution enables fast, reliable, and high-precision turning between adjacent work rows, significantly reducing reliance on open space at the edge of the field. Furthermore, the solution is more adaptable to the shape of the plot and the space at the edge of the field, enabling large agricultural machinery (such as cotton harvesters and combine harvesters) to perform stable turning in narrower field areas.

[0052] In summary, when the target agricultural machinery is harvesting in the target plot, it can operate continuously along pre-planned parallel work rows. When the target machinery operates along the first centerline in the first work row and reaches the first vertex of the first work row, it needs to turn to the next work row, starting again from the second vertex of the second work row. At this point, the target machinery needs to determine the position of the second vertex based on the centerline of the second work row. After obtaining the position of the second vertex, a first circle tangent to the second centerline and at the second vertex can be generated based on this position and the target machinery's minimum turning radius. Then, the target machinery only needs to find a drivable first path in the first work row and reach the first intersection point formed by the first path and the first circle. It can then reverse along the first path to the first intersection point and, along the center of the circle formed by the minimum turning radius, directly reach the second vertex to begin harvesting in the second work row. This scheme only changes the vehicle's forward and reverse state at the first intersection point, and by reversing along the first path and then moving forward through the first circle, it minimizes the need for turning space at the edge of the field, while ensuring the efficiency and reliability of autonomous driving.

[0053] Figure 5 shows a flowchart of an agricultural machinery steering control method according to an embodiment of the present invention, as follows: Figure 5 As shown, the method includes: Step 501: When the target agricultural machinery harvests along the first center line to the first vertex on the boundary of the first work row, determine the second vertex in the second work row.

[0054] Step 502: Determine the first circumference based on the second vertex and the minimum turning radius of the target agricultural machinery; the first circumference is tangent to the second centerline at the second vertex.

[0055] Steps 501-502 can be found in [reference]. Figure 3 The embodiments shown are not described in detail here.

[0056] Step 503: The intersection of the boundary line between the first work row and the second work row and the first circumference is determined as the first endpoint E.

[0057] After constructing the first circle, this embodiment further calculates the geometric intersection of the circle with the boundary of the second work row. Since the boundary line between the first and second work rows may have 0 or 1 intersection with the first circle, when there are 0 intersections (i.e., no intersections), it means that the width of the work row is greater than twice the minimum turning diameter of the target agricultural machinery, and the first circle and the second circle may not have any intersections. Therefore, this embodiment is not applicable to this method.

[0058] When there is one intersection point, it means that the width of the work row is less than twice the minimum turning diameter of the target agricultural machine. In this case, the first circle must have a trajectory in the first work row, and subsequent steps can be executed.

[0059] Step 504: Determine the second circumference based on the position of the first vertex and the minimum turning radius of the target agricultural machinery; the second circumference is tangent to the first centerline at the first vertex.

[0060] To determine the feasible range for the agricultural machinery to reverse into the turning zone from the first vertex, embodiments of this application construct a second circle based on the first vertex. Specifically, as shown... Figure 4 As shown, the direction of the first centerline can be determined at the first vertex; based on the direction vector, a circle tangent to the first centerline is constructed at that position, and the radius of this circle is also set to the radius of the target agricultural machine under the minimum turning constraint. At this time, the second circle represents the limit value of the curve that the agricultural machine may form when it reverses from the first vertex.

[0061] Step 505: The intersection of the second circle and the first circle within the first work row is taken as the second endpoint.

[0062] After obtaining the second circumference, this embodiment calculates the intersection point of the first and second circumferences. Since the two circles may have two geometric intersection points, this embodiment selects only the intersection point that meets the following conditions as the second endpoint (i.e., B): the intersection point must be located within the internal area of ​​the first working row; the intersection point must be within the range that the agricultural machinery can reach when reversing; and the position of the intersection point must ensure that there is reachability between the arc segment and the reversing path.

[0063] Step 506: Select the first intersection point in the first arc segment formed by the first endpoint and the second endpoint.

[0064] A defined arc segment is formed on the first circumference through the first endpoint E and the second endpoint B. In this embodiment, a suitable key node for switching from reverse to forward is selected on this arc segment, namely the first intersection point.

[0065] Preferably, in this embodiment of the application, the second endpoint B can be directly used as the first intersection point, in which case, as follows: Figure 4 As shown, the target agricultural machine generates a backward path from AB along the second circumference and a forward path from B to D along the first circumference. At this time, the path length is the shortest among the first paths selected by the target agricultural machine.

[0066] like Figure 4As shown, when the target agricultural machine reaches point B, its speed direction needs to undergo a certain abrupt change. The angle of this abrupt change is the angle between the tangent of the first circle at point B and the tangent of the second circle at point B. If this angle is too large, for example, greater than the rear wheel steering angle of the target agricultural machine, the machine's ability to turn in place may not meet the requirements for transitioning from the first circle to the second circle. In this case, it is necessary to obtain the first intersection point that meets the requirements.

[0067] In one alternative implementation, Figure 6 This illustration shows a trajectory selection diagram related to an embodiment of this application, such as... Figure 6 As shown, if the angle α between the tangent of the first circle at the second endpoint B and the tangent of the second circle at the second endpoint B is greater than the rear wheel steering angle, then the target agricultural machine generates a third circle with the first vertex A as the tangent point and the target radius, and the center of the third circle is close to the second working row; the intersection point N of the third circle and the first arc segment is taken as the first intersection point. The target radius is greater than or equal to the minimum turning radius of the target agricultural machine.

[0068] In the above scheme, if the included angle α is greater than the rear wheel steering angle, it means that the on-the-spot steering ability of the target agricultural machinery may not meet the requirement of turning from the first circle to the second circle at the second endpoint B. In this case, the second endpoint B cannot be directly selected as the first intersection point.

[0069] Therefore, this application provides a trajectory selection scheme with a smaller requirement for the rear wheel steering angle. That is, with A as the tangent point, a third circle with a larger radius is drawn. At this time, the third circle will intersect the first arc segment BE at point N. If point N is directly taken as the first intersection point, then the path of the target agricultural machine becomes from A back to N, and then moves along the first circle to D at point N. At this time, the angle between the tangent of the first circle at point N and the tangent of the third circle at point N is significantly smaller than α, which has a lower requirement for the rear wheel steering angle of the target agricultural machine.

[0070] Furthermore, in this embodiment of the application, the target radius can be one of several preset radii. The control device of the target agricultural machinery can generate each candidate circumference according to each preset radius. Then, among each candidate circumference, each candidate intersection point generated by each candidate circumference and each first arc segment is determined. Then, for each candidate intersection point, the candidate angle between the tangent of the candidate circumference at the candidate intersection point and the tangent of the first arc segment at the candidate intersection point is calculated, and the target radius is selected from the preset radii whose corresponding candidate angle is less than the rear wheel steering angle.

[0071] Furthermore, if multiple preset radii correspond to candidate angles that are all smaller than the rear wheel steering angle, then the smallest preset radius can be selected as the target radius from among the preset radii whose corresponding candidate angles are smaller than the rear wheel steering angle. Figure 6It can be seen that the smaller the preset radius, the smaller the distance the target agricultural machine travels backward through the third circle to the first intersection point, and the smaller the distance it travels from the first intersection point to the second vertex. This can improve the turning efficiency of the target agricultural machine while ensuring that it can complete the turning operation.

[0072] In one alternative implementation, such as Figure 6 As mentioned above, the first centerline and the first circumference also intersect at a point. This means that after the target agricultural machinery completes harvesting along the first centerline, it can reverse back to the intersection of the first centerline and the first circumference. If the angle between the tangent at this intersection and the first centerline is less than the rear wheel steering angle, the target agricultural machinery can move from this intersection along the first circumference to point D. If the target agricultural machinery operates according to this scheme, there is no need to simulate and generate the first and third circumferences, significantly reducing the computational load during the navigation process.

[0073] Step 507: Generate a first path from the first vertex to the first intersection point; the first intersection point is located within the first job line.

[0074] In this embodiment, the first path is generated based on the positional relationship between the first vertex and the first intersection point, combined with the kinematic constraints of the agricultural machinery (such as the maximum steering angle, minimum reversing radius, maximum reversing speed, etc.).

[0075] Step 508: Based on the first path and the first circumference, control the target agricultural machinery to turn and run to the second vertex.

[0076] Furthermore, in this embodiment, the control device of the target agricultural machinery can perform real-time control of the target agricultural machinery based on the first path and the first circumference. The real-time control steps are as follows: The real-time motion state of the target agricultural machinery is obtained, including its real-time position, real-time speed, and real-time steering angle. Based on the real-time motion state, the first path, and the first circle, the real-time error of the target agricultural machinery is obtained, including its lateral error and heading error. Based on the lateral error and heading error, a feedback control quantity is calculated. Based on the feedback control quantity, the real-time speed and real-time steering angle of the target agricultural machinery are controlled.

[0077] Specifically, in the embodiments of this application, the real-time motion state of the target agricultural machinery can be described by a kinematic single-track model based on Ackerman vehicles, and its formula is as follows:

[0078] Where v is the longitudinal speed of the target agricultural machinery, and L is the wheelbase of the target agricultural machinery. For heading angle, is the rear wheel steering angle; x and y are the coordinates of the target agricultural machinery in the xy coordinate system, respectively. The derivative of the x-coordinate represents the velocity of the target agricultural machinery along the x-axis; similarly... The derivative of the y-coordinate represents the velocity of the target agricultural machinery along the y-axis. Then the error state can be obtained in trajectory-aligned (Frenet) coordinates: , ; in For lateral error, For heading error; The turning angle at the current moment; The control input is defined as the rate of change of the steering angle.

[0079] Then, based on the discrete error dynamics under the low-speed, small-angle approximation, the relationship between the above error states is constructed: ; in, The reference path curvature is T; T is the discrete time step. This can be further summarized into the following formula: ; in , , ; It is the error state predicted at time K; Construct a quadratic cost function: , ; Where Q is the state error weight matrix (symmetric positive semi-definite); R is the control input weight matrix (symmetric positive definite). To predict the length of the time domain; To control the time domain length; J(U) is the cost function; C is the output matrix; Combined with the following constraints , The optimal control sequence can be obtained by solving. Taking only the first element of the sequence is the feedback control quantity. .

[0080] Furthermore, when the control equipment controls the real-time speed and steering angle of the target agricultural machinery based on the feedback control quantity, the control equipment of the target agricultural machinery can also correct the feedback control quantity through a feedforward correction quantity, as follows: The control equipment acquires the feedforward correction amount corresponding to the target agricultural machine, and then acquires the real-time control amount of the target agricultural machine based on the feedback correction amount and the feedforward correction amount; finally, it controls the real-time speed and real-time steering angle of the target agricultural machine based on the real-time control amount.

[0081] In other words, for the j-th turn in the target plot, the actual control quantity issued to the target agricultural machinery is... .

[0082] in, It is the feedforward correction amount at the k-th discrete position when the double circular arc turning mode is executed for the j-th time. This feedforward control amount is essentially a "memory bias" superimposed on the MPC, thereby offsetting the systematic error that always occurs on this double circular arc.

[0083] Furthermore, in this embodiment, the feedforward correction amount is not constant, but can be updated in real time based on the operating records of the target agricultural machinery. Specifically: The tracking error of the target agricultural machine from the first vertex to the second vertex is obtained; the feedforward error is updated based on the tracking error; wherein the updated feedforward error is used to generate the real-time control quantity when the target agricultural machine moves from the second vertex to the starting point of the harvesting operation of the third working row.

[0084] To improve the path tracking accuracy of the target agricultural machinery during continuous row turning, the above steps are essentially a technical solution for real-time adaptive updating of the feedforward correction. The feedforward correction provides feedforward compensation to the control commands when the target agricultural machinery executes a turning path from the first working row to the second working row, making the target agricultural machinery's trajectory more closely match the planned path. Furthermore, to avoid the gradual accumulation of control deviations caused by vehicle model deviations, actuator lag, or changes in ground conditions, this embodiment dynamically updates the feedforward correction to achieve self-learning and continuous optimization of control performance.

[0085] Specifically, as the target agricultural machinery moves from the first apex to the second apex, its control equipment continuously acquires operational records for this phase. These records include the target machinery's real-time position, real-time heading, real-time speed, real-time steering angle, and the reference position and heading corresponding to the planned path. Based on these operational records, the control equipment calculates the tracking error for this phase. The tracking error can include lateral deviation, heading deviation, and statistical errors derived from the deviation sequence, such as average deviation, mean square deviation, and maximum deviation.

[0086] After acquiring the tracking error of the target agricultural machinery from the first apex to the second apex, the control equipment adjusts the feedforward correction amount according to a preset update strategy. The updated feedforward correction amount is stored in the target agricultural machinery's control equipment and used as the feedforward input for the next steering control. For example, when the target agricultural machinery is preparing to move from the second apex to the starting point of the third work row, the control equipment uses the updated feedforward correction amount and the feedback control amount to generate a real-time control amount, and controls the real-time speed and steering angle of the target agricultural machinery accordingly. In this way, the target agricultural machinery can gradually reduce systematic deviations during continuous steering operations, improving the stability and accuracy of path tracking.

[0087] Specifically, in this embodiment, during the path travel of the target agricultural machinery to complete a turn, the travel trajectory is evenly segmented according to the arc length, and a feedforward correction table indexed by the arc length position is established and initialized to zero. During operation, based on the projected position of the vehicle on the reference curve, the feedforward correction is obtained from the table according to the current position or by interpolation, and superimposed with the real-time MPC output as the actual steering command. After completing a turn, the tracking deviation along the way is written back according to the corresponding arc length position and the correction table is updated. In subsequent repeated executions of the turning path, the system gradually corrects and solidifies the position-related control compensation accordingly.

[0088] In other words, this tracking error It can be set as follows: ; in, This is the desired reference position. The actual output position at time k during the j-th execution of the turning process.

[0089] Furthermore, to prevent abnormal operating conditions from being learned and solidified, this embodiment of the application can also set millimeter-wave radar environment gating for iterative learning. Specifically, during each turning process, environmental feature vectors (such as the lateral distance from the crop boundary to the reference trajectory, the number / nearest distance of obstacles in the preset sector, occupancy rate, etc.) are extracted from the millimeter-wave radar point cloud and recorded as the current environmental features; these features are compared with historical normal samples for similarity. When the similarity is higher than a threshold, it is determined that the environment is consistent, and the gating signal is set to 1, allowing iterative updates to the feedforward correction table of the template; otherwise, it is set to 0, freezing the update.

[0090] In other words, the embodiments of this application can extract environmental features (based on millimeter-wave radar). (Point cloud information such as terrain obstacles in the turning area), and historical features Perform similarity assessment:

[0091] To learn the gating factor, the gating factor is set to 1 when the similarity between the obstacle distribution and crop boundary detected by the millimeter-wave radar and the historical template environment is greater than a preset threshold, and 0 otherwise, in order to avoid incorrect updates to the feedforward control in abnormal situations such as temporary obstacle detours.

[0092] When the gating factor is 1, the feedforward correction can be updated using the iterative learning law: Where L is a constant; For tracking error; This represents the actual output position at time k during the j-th execution of the turning process; This represents the actual output position at time k during the (j+1)th execution of the turning process.

[0093] Figure 7 A complete flowchart of the agricultural machinery control involved in the embodiments of this application is shown. Figure 7 As shown, after the target agricultural machinery begins operation, it can collect relevant information about the target plot through various sensors installed on it, including the field edge, harvested areas, and unharvested areas. If the target agricultural machinery has finished harvesting, the machinery control process ends; if the target agricultural machinery has not finished harvesting, it continues with subsequent operations.

[0094] During the operation of the target agricultural machinery, a turning path will be planned and generated based on the terrain information of the target plot and the scheme shown in the embodiments of this application, such as the preferred method. Figure 4 The double-circular-arc turning path is shown. Then, in this embodiment, it is necessary to further determine whether the path is located in a safe and feasible area, such as whether there are obstacles in the path or whether the path exceeds the edge of the field; if feasible, then considering environmental constraints (boundaries, radar safety constraints, etc.), the LMPC tracking controller is used to control the turning of the target agricultural machinery during agricultural operations.

[0095] In summary, when the target agricultural machinery is harvesting in the target plot, it can operate continuously along pre-planned parallel work rows. When the target machinery operates along the first centerline in the first work row and reaches the first vertex of the first work row, it needs to turn to the next work row, starting again from the second vertex of the second work row. At this point, the target machinery needs to determine the position of the second vertex based on the centerline of the second work row. After obtaining the position of the second vertex, a first circle tangent to the second centerline and at the second vertex can be generated based on this position and the target machinery's minimum turning radius. Then, the target machinery only needs to find a drivable first path in the first work row and reach the first intersection point formed by the first path and the first circle. It can then reverse along the first path to the first intersection point and, along the center of the circle formed by the minimum turning radius, directly reach the second vertex to begin harvesting in the second work row. This scheme only changes the vehicle's forward and reverse state at the first intersection point, and by reversing along the first path and then moving forward through the first circle, it minimizes the need for turning space at the edge of the field, while ensuring the efficiency and reliability of autonomous driving.

[0096] This application also provides an agricultural machinery steering control device for implementing the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0097] This application provides a steering control device for agricultural machinery. Figure 8 This is a schematic diagram of the structure of an agricultural machinery steering control device provided in an embodiment of this application. The device includes: The location acquisition module 801 is used to determine the second vertex in the second work row when the target agricultural machinery harvests along the first center line to the first vertex on the boundary of the first work row; the second vertex is the intersection of the second center line in the second work row and the boundary of the second work row; the second center line is parallel to the first center line; the first work row and the second work row are adjacent and parallel work rows in the target plot; The circumference determination module 802 is used to determine the first circumference based on the second vertex and the minimum turning radius of the target agricultural machinery; the first circumference is tangent to the second centerline at the second vertex; The path generation module 803 is used to select a first intersection point within the first circle and generate a first path from the first vertex to the first intersection point; the first intersection point is located within the first work row; The agricultural machinery control module 804 is used to control the target agricultural machinery to turn and run to the second vertex according to the first path and the first circumference.

[0098] In summary, when the target agricultural machinery is harvesting in the target plot, it can operate continuously along pre-planned parallel work rows. When the target machinery operates along the first centerline in the first work row and reaches the first vertex of the first work row, it needs to turn to the next work row, starting again from the second vertex of the second work row. At this point, the target machinery needs to determine the position of the second vertex based on the centerline of the second work row. After obtaining the position of the second vertex, a first circle tangent to the second centerline and at the second vertex can be generated based on this position and the target machinery's minimum turning radius. Then, the target machinery only needs to find a drivable first path in the first work row and reach the first intersection point formed by the first path and the first circle. It can then reverse along the first path to the first intersection point and, along the center of the circle formed by the minimum turning radius, directly reach the second vertex to begin harvesting in the second work row. This scheme only changes the vehicle's forward and reverse state at the first intersection point, and by reversing along the first path and then moving forward through the first circle, it minimizes the need for turning space at the edge of the field, while ensuring the efficiency and reliability of autonomous driving.

[0099] Please see Figure 9 , Figure 9 This is a schematic diagram of the structure of an electronic device provided in an optional embodiment of the present invention. This electronic device can be a computer device used to execute the above-described method. Figure 9 As shown, the electronic device includes one or more processors 10, a memory 20, and interfaces for connecting the various components, including high-speed interfaces and low-speed interfaces. The various components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processor can process instructions executed within the electronic device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces).

[0100] The processor 10 may further include a hardware chip. This hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0101] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.

[0102] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the use of the electronic device based on the display of a mini-program landing page. Furthermore, the memory 20 may include high-speed random access memory (RAM), and may also include non-transient memory, such as at least one disk storage device, flash memory device, or other non-transient solid-state storage device. The memory 20 may include volatile memory, such as RAM; the memory may also include non-volatile memory, such as flash memory, hard disk, or solid-state drive; the memory 20 may also include combinations of the above types of memory.

[0103] The electronic device also includes a communication interface 30 for communicating with other devices or communication networks.

[0104] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code, which, when accessed and executed by the computer, processor, or hardware, implements the methods shown in the above embodiments.

[0105] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An agricultural machine steering control method characterized by, The method comprises: determining a second vertex in a second work row when a target agricultural machine harvests along a first center line to a first vertex on a first work row boundary; the second vertex is an intersection of a second center line in the second work row and a second work row boundary; the second center line is parallel to the first center line; the first work row and the second work row are adjacent and parallel work rows in a target land plot; determining a first circumference according to the second vertex and a minimum turning radius of the target agricultural machine; the first circumference is tangent to the second center line at the second vertex; selecting a first intersection point in the first circumference and generating a first path from the first vertex to the first intersection point; the first intersection point is located in the first work row; controlling the target agricultural machine to turn and run to the second vertex according to the first path and the first circumference.

2. The method of claim 1, wherein, The selecting the first intersection point in the first circumference comprises: obtaining a head boundary of the target land plot; judging whether there is an intersection point between the first circumference and the head boundary of the target land plot; if there is no intersection point between the first circumference and the head boundary of the target land plot, selecting the first intersection point in the first circumference.

3. The method of claim 2, wherein, The selecting the first intersection point in the first circumference comprises: determining a first end point as an intersection point between an interface line between the first work row and the second work row and the first circumference; determining a second circumference according to a position of the first vertex and the minimum turning radius of the target agricultural machine; the second circumference is tangent to the first center line at the first vertex; determining a second end point as an intersection point between the second circumference and the first circumference in the first work row; selecting the first intersection point in a first arc segment formed by the first end point and the second end point.

4. The method of claim 3, wherein, The first intersection point is the second end point of the first arc segment.

5. The method of claim 3, wherein, The controlling the target agricultural machine to turn and run to the second vertex according to the first path and the first circumference comprises: obtaining a real-time motion state of the target agricultural machine; the real-time motion state comprises a real-time position, a real-time speed and a real-time turning angle of the target agricultural machine; obtaining a real-time error of the target agricultural machine according to the real-time motion state of the target agricultural machine, the first path and the first circumference; the real-time error comprises a lateral error and a heading error; calculating a feedback control amount according to the lateral error and the heading error; controlling the real-time speed and the real-time turning angle of the target agricultural machine according to the feedback control amount.

6. The method of claim 5, wherein, The controlling the real-time speed and the real-time turning angle of the target agricultural machine according to the feedback control amount comprises: obtaining a feedforward correction amount corresponding to the target agricultural machine; obtaining a real-time control amount of the target agricultural machine according to the feedback correction amount and the feedforward correction amount; controlling the real-time speed and the real-time turning angle of the target agricultural machine according to the real-time control amount.

7. The method of claim 6, wherein, The method further comprises: obtaining a tracking error of the target agricultural machine from the first vertex to the second vertex; updating the feedforward error according to the tracking error. The updated feedforward error is used to generate a real-time control amount of the target agricultural machine when the target agricultural machine runs from the second vertex to a starting point of the harvesting operation of the third work row.

8. An agricultural machine steering control apparatus characterized by comprising: The device comprises: a position acquisition module configured to determine a second vertex on a second work row when a target agricultural machine performs a harvesting operation along a first center line to a first vertex on a first work row boundary; the second vertex is an intersection of a second center line and a second work row boundary in the second work row; the second center line is parallel to the first center line; the first work row and the second work row are adjacent and parallel work rows in a target land plot; a circle determination module configured to determine a first circle according to the second vertex and a minimum turning radius of the target agricultural machine; the first circle is tangent to the second center line at the second vertex; a path generation module configured to select a first intersection point in the first circle and generate a first path from the first vertex to the first intersection point; the first intersection point is located in the first work row; an agricultural machine control module configured to control the target agricultural machine to turn and run to the second vertex according to the first path and the first circle.

9. An electronic device, comprising: comprise: a memory and a processor in communication connection with each other, the memory storing computer instructions, and the processor executing the computer instructions to perform the agricultural machine turning control method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions for causing a computer to perform the agricultural machine turning control method according to any one of claims 1 to 7.

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