Method for making an agricultural robot execute a half-turn maneuver

Abstract

The invention relates to a method for determining a trajectory for an agricultural machine (12), executing a half turn between a first row (N), referred to as exit row N, and a second row (N +1), referred to as entry row, this method being implemented by a computer, said agricultural robot comprising at least one geometric parameter and moving over an agricultural field or plot, the method being characterized in that it comprises: a) - a step of calculating at least one half-turn path (101) that the robot will follow during at least part of the half-turn maneuver to exit the exit row N and enter the entry row N +1, b) - a step of calculating at least one exit trajectory between the exit row N and a half-turn path and at least one entry trajectory between this half-turn path and the entry row N +1, c) - a step of assembling the trajectories thus calculated with the half-turn path to form a half-turn trajectory from row N to row N +1.

Description

[0001] DESCRIPTION

[0002] TITLE: METHOD FOR A TURNING AROUND FOR AN AGRICULTURAL ROBOT - TECHNICAL FIELD AND PRIOR ART

[0003] The invention relates to the field of guidance techniques and maneuvering methods for making an agricultural robot perform a U-turn.

[0004] The invention finds applications in particular in the field of row crop processing.

[0005] Guidance methods are known for agricultural robots within row crops. Indeed, in order to automate various processing operations carried out by agricultural robots, these robots must be able to move autonomously between crop rows.

[0006] The most difficult maneuver to perform is the U-turn, which allows the agricultural robot to move from one row of crops to another. This requires significant space in the field.

[0007] This area cannot be used for planting crops, as these would risk being crushed by the agricultural robot. It is therefore important to limit the space occupied by the agricultural robot during this maneuver and to ensure that it does not take place in areas containing crops.

[0008] However, there are many different field configurations, as well as agricultural robots with varying geometries and capabilities. Therefore, existing guidance methods that provide generic processes, without taking into account either the specific characteristics of the terrain on which the agricultural robot operates or the individual characteristics of the robots themselves, are not suitable.

[0009] For example, in Figure IA, we see a plot of land that an agricultural robot must cultivate, where herringbone rows are located near a physical obstacle (e.g., a ditch and a road). The robot has very little room to maneuver. Figure IA shows a significant offset between the rows (herringbone pattern). The area in front of these rows does not allow for a U-turn, so we can see that the row arrangement is adapted so that the robot follows path I (10, 20, ..., 210) to reach a row further along where it can maneuver. For example, after row 1, the robot will cultivate row 2, located several rows away from row 1.

[0010] In another example, illustrated in Figure IB, an agricultural robot must process a plot in which herringbone rows are located near various physical obstacles, particularly trees. The robot must perform these maneuvers between the trees, and a self-calculated U-turn would generate collisions.

[0011] None of the current systems can simultaneously meet all the required needs, namely to offer a technique that allows for a U-turn adapted to each agricultural robot, taking into account the specific characteristics of the terrain in which it operates, while protecting the crops.

[0012] DESCRIPTION OF THE INVENTION

[0013] The invention relates first to a method of determining a half-turn trajectory of an agricultural robot (or an agricultural machine, or an autonomous agricultural machine or highly automated agricultural machine (HAAM)), to move or moving between or on rows of crops.

[0014] In a process or device (robot) according to the invention (shown below):

[0015] - the agricultural robot is for example wheeled or tracked, and / or of the "straddle" type for crops or of the inter-row type;

[0016] - and / or at least one treatment tool is for example and without limitation of the type hoe, and / or seeder, and / or inter-row cultivator, and / or weeding finger (for example of the Kress type, registered trademark), and / or clod-breaking disc, and / or notched disc, and / or brush, and / or rigid tooth, and / or tine harrow, and / or opening share, and / or leaf guards, and / or sprayer;

[0017] - and / or the agricultural robot is used for example for one or more crop treatment missions, in one or more crop plots including in particular crop rows.

[0018] The invention relates in particular to a method for determining a U-turn trajectory for an agricultural machine, between a first row (N), called the exit row, and a second row (N+1), called the entry row, this method being implemented by computer, said agricultural robot comprising geometric parameters and operating on an agricultural field or a plot comprising an area of ​​row crops, which can be mapped in the form of a working map, said agricultural field comprising a plurality of consecutive rows of crops, including at least a first row and a second row, two consecutive rows of crops being, for example, separated by a working row, the method being characterized in that it comprises: a) - a calculation step of at least one U-turn path that the robot will follow during at least part of the U-turn maneuver to exit the exit row N and enter the entry row N+1, b) - a calculation step,for example using Bézier curves, at least one exit trajectory between the exit rank N and a U-turn path and at least one entry trajectory between this U-turn path and the entry rank N+1, c) - a step of assembling the trajectories thus calculated with the CDDT to form a U-turn trajectory from rank N to rank N+1.

[0019] Depending on specific aspects of the implementation of the invention, it may include one or more of the following steps:

[0020] - a step to verify the validity of the resulting U-turn trajectory; this step is based, for example, on:

[0021] * on the number of intersection points between the U-turn path and the working path(s), this is for example the case for a "manual" U-turn path (not calculated, and which may have been entered or stored in the robot's computer by a user);

[0022] * or based on (this is particularly the case for a calculated or auto-generated path):

[0023] ° of the distance of the U-turn from the crops;

[0024] ° and / or the maximum rotation angle(s) imposed on the robot by the U-turn trajectory;

[0025] ° and / or the presence of one or more reverse phases; - and / or the turning paths can be generated or calculated according to the shape of the field or plot and the geometric parameters of the robot;

[0026] - and / or the calculation of step a) of at least one turnaround path, which the robot will follow for at least part of the turnaround maneuver to exit row N of exit and enter row N+l of entry, can be carried out according to the contours of the plot, and / or the dimensions of the robot, and / or the size of the tool and / or the space allowing to carry out a maneuver;

[0027] - and / or a U-turn path can be selected from among a plurality of U-turn paths;

[0028] - and / or the geometric parameter(s) of the robot include at least one of the following parameters: the turning radius of the robot and / or a template or dimension of the agricultural robot, for example a distance between the center of the robot and its rearmost point from the center and / or a distance between the center of the robot and its frontmost point from the center;

[0029] - and / or we can calculate the minimum distance (Ml) between a U-turn path and the last point of the output rank N and / or the first point of the input rank N+l; for example, we calculate or evaluate: the distance between the last point (P3) of the output rank N and the U-turn path and compare it to the minimum distance (Ml); and / or the distance between the first point (P4) of the input rank N + l and the U-turn path and compare it to the minimum distance Ml;

[0030] - and / or we can further calculate, in particular during step b), or step b) may include the calculation of: the intersection (11) between the U-turn path and the direction of the exit row N and / or the intersection (12) between the U-turn path and the direction of the entry row N+l;

[0031] - and / or we can evaluate whether, on its exit trajectory from row N of exit and / or on its entry trajectory into row N + l of entry, the robot does not move away from the crop beyond a safety distance (D4);

[0032] - and / or step b) can be carried out with a U-turn path entered by a user instead of the U-turn path calculated in step a); - and / or step b) can be a function of a steering angle of the agricultural robot;

[0033] - and / or the exit trajectory between the exit rank N and a U-turn path and / or the entry trajectory between this U-turn path and the entry rank (N+l) may include at least one phase of robot reversal;

[0034] - and / or the U-turn trajectory may include at least one phase of robot reversal between the exit trajectory between the exit rank N and a U-turn path and the entry trajectory between this U-turn path and the entry rank (N+l);

[0035] - and / or the U-turn trajectory may include at least one part:

[0036] * which is tangent on one side to the end of the exit row N and to the U-turn path and / or to the U-turn path and to the end of the entry row N+l;

[0037] * and / or which allows the widest possible angle of rotation while taking into account the limits imposed by the robot;

[0038] - and / or Bézier curves may have 4 control points;

[0039] - and / or the exit trajectory between the exit rank N and a U-turn path and the entry trajectory between this U-turn path and the entry rank (N+l) may intersect.

[0040] The invention also relates to a method for moving an agricultural machine comprising:

[0041] - the determination of a U-turn trajectory according to a method according to the invention, as defined above or in the rest of the description;

[0042] - a step of transmitting orders to control means of the agricultural robot for the execution of the U-turn trajectory determined in the previous step by the agricultural robot;

[0043] - the movement of the agricultural machine along said U-turn trajectory. The invention also relates to a system for determining a U-turn trajectory of an agricultural machine, between a first row (N), called the exit row, and a second row (N+1), called the entry row, comprising means, or electronic means, configured or programmed to implement a method according to the invention, as defined above or in the rest of the description. The invention also relates to an agricultural robot comprising wheels or tracks, means for controlling the wheels or tracks, means for moving the machine forward in a main direction of travel, a computer, one or more processing tools, and means for moving the processing tool(s), the computer being configured or programmed to implement a method according to the invention, as defined above or in the rest of the description.

[0044] The invention also relates to a device for determining a U-turn trajectory of an agricultural machine, comprising configured means programmed to implement a method according to the invention as defined above or in the rest of the description.

[0045] The invention also relates to a computer program comprising instructions for implementing a method according to the invention, as defined above or in the rest of the description, when this program is executed by a computer.

[0046] The invention also relates to a computer-readable recording medium on which a computer program according to the invention is recorded.

[0047] BRIEF DESCRIPTION OF THE DRAWINGS

[0048] [Fig. IA] - [Fig. IB] represent 2 examples of situations that pose a problem for turning around agricultural robots;

[0049] [Fig. 2] represents crop rows and a case of a U-turn path with a rectangular map) with various parameters that can be taken into account in the context of an embodiment of the invention;

[0050] [Fig. 3A] - [Fig. 3B] represent an example of an embodiment of the invention with a complex half-turn path, having a herringbone shape, before (figure 3A) and after smoothing (figure 3B);

[0051] [Fig. 4] represents an embodiment of the invention taking into account a manually generated U-turn path;

[0052] [Fig. 5A] - [Fig. 5B] illustrate an example of generating an output path according to the invention, using Bézier curves, within the scope of the present invention; [Fig. 6A] - [Fig. 6B] illustrate another example of generating an output path according to the invention, using Bézier curves, within the scope of the present invention;

[0053] [Fig. 7] illustrates an example of a U-turn according to the invention, in one step;

[0054] [Fig. 8] illustrates an example of a U-turn according to the invention, in 3 steps, including a reverse gear;

[0055] [Fig. 9A] - [Fig. 9B] illustrate another example of a U-turn according to the invention, in 3 steps, including a reverse, for a locally herringbone map;

[0056] [Fig. 10] illustrates an example of a U-turn according to the invention, with 2 complex maneuvers, for a locally herringbone map;

[0057] [Fig. 11] illustrates another example of a half-turn according to the invention, with a complex-shaped field, with a robot capable of turning on itself;

[0058] Figure 12 represents a system, comprising an agricultural robot, capable of implementing the invention;

[0059] Figure 13 represents a computer device for an agricultural robot according to the invention or capable of implementing a method according to the invention;

[0060] [Fig. 14A] - [Fig. 14B] - [Fig. 14C] show schematic examples of robots and their respective centers.

[0061] DETAILED DESCRIPTION OF SPECIFIC METHODS OF IMPLEMENTATION

[0062] An agricultural robot 12 (or an agricultural machine, or an autonomous agricultural machine, or a highly automated agricultural machine (HAAM)) to which the invention can be applied:

[0063] - is for example wheeled 16, 18 (figures 14A, 14B) or tracked 17 (figure 14C), and / or of the "straddle" type for crops or of the inter-row type;

[0064] - and / or may be equipped with a tool 14 (shown schematically in figures 2, 14B and 14C); this is for example and without limitation a tool of the type hoe, and / or seeder, and / or inter-row, and / or weeding finger (for example of type Kress, registered trademark), and / or clod-breaking disc, and / or notched disc, and / or brush, and / or rigid tooth, and / or tine harrow, and / or opening share, and / or leaf guard, and / or sprayer.

[0065] Figure 2 illustrates various parameters that can be considered in embodiments of the invention. In this figure, line 10i (or, in subsequent figures, lines or paths IO2, IO3, etc.) represents the layout of a portion of a turning path (or CDDT). Generally, within the scope of the present invention, a turning path corresponds to at least a portion of the route to be followed to perform turning maneuvers, as well as to connect the exit of one row to the entrance of the next.

[0066] This path can be automatically generated or calculated by the robot's computer during planning, taking into account the plot's boundaries, the robot's dimensions, the tool's footprint, and the space available for maneuvering. This automatically generated path can handle certain scenarios. However, this path can also be created manually and added to the map to manage specific situations (for example, in the case of an obstacle and / or a longer path, etc.).

[0067] The agricultural robot 12 (or agricultural machine, or autonomous agricultural machine, or highly automated agricultural machine (HAAM)) has followed the work path N (also called the exit row), which ends at point P3 (the last point or exit point of row N), and is about to follow the work path N+1 (also called the entry row), which begins at point P4 (the first point or entry point of row N+1). It should be noted that, generally speaking and within the scope of this invention, the numbered row or work path N+1 is the row following which the robot will continue its mission; it is not necessarily the row immediately adjacent to row or work path N in the field or plot. We will see examples later, in connection with Figures 10 and 11, in which the entry row is the 2nd. ème rank after the exit rank. The CDDT is located at a distance from point P3 and at a distance from point P4.

[0068] The extremities of one part of rank N, or the exit path, and of the other part of rank N+1, or the entry or re-entry path following this exit, are preferably parallel, so as to avoid crossings, as can be seen in the various figures. The computer will be able to calculate the position of PI and P2, defined as follows:

[0069] PI is the exit point of row N, corresponding to the center C of the robot when its entire rear footprint is outside the row; figures 14A-14C show examples of centers C of various robots: this center is the midpoint of the 2 wheels if the robot has only 2 wheels or the midpoint of the 4 wheels or of the parallelogram formed by the 4 wheels if the robot has 4 wheels (case of figures 14A and 14B) or between the two tracks 17 (case of figure 14C) if the robot is tracked; more generally, it is the point located in the middle of the rolling part(s) of the robot;

[0070] P2 is the entry point of rank N+1, corresponding to the center C of the robot when its entire front bulk is outside the rank. Furthermore, the computer can have information on the position of points P3 and P4, already defined above, which are respectively the last point of rank N and the first point of rank N+1 (or the next rank to which the robot will continue its mission).

[0071] Furthermore, we call:

[0072] DI: the robot's template (i.e., the distance between the robot's center C and its furthest rear point); taking this distance DI into account allows the positioning of point PI.

[0073] D2 is the distance between the center C of the robot and its furthest forward point; taking into account this distance D2 allows the positioning of point P2.

[0074] We also define: the distance D3 as the exit and entry distance defined by the user to keep maneuvers away from crops; it is in fact a safety margin that can be introduced by the user; D3 can be zero, or not;

[0075] The turning radius R of the robot; this radius R is 0 cm for robots that can turn on the spot; Ml: the minimum distance between a U-turn path and the last point of a row (entry or exit); Ml is in fact equal to the maximum or the greater of the 2 distances (D1+D3+R) and (D2+D3+R); Ml can be considered, via D3, as taking into account the shape of the plot on which the robot will move.

[0076] Figure 2 shows robot 12, equipped with its tool 14, after exiting rank N, and then before entering rank N + 1. On the right of the figure, the distance M1 is shown. In this example, the distance D3 is non-zero.

[0077] The robot's computer can have in memory or calculate or estimate the distances Dl, D2, D3 and R. As we will see later, the turnaround paths are generated according to the shape of the plot (via D3 or Ml (which encompasses D3)) and the geometric parameters or distances Dl, D2, D3 and R, among which Dl, D2 and R are geometric parameters of the robot.

[0078] In the following sections, we can also use the following points (whose position is then calculated):

[0079] - It: intersection between the CDDT and the exit segment of rank N.

[0080] - 12: Intersection between the CDDT and the entry segment of rank N+1.

[0081] To find or calculate point 11, or 12 respectively, we take, for example, the orientation of the mean of rank N, or rank N+1 respectively. This orientation of the mean can be calculated based on the orientation of the last few meters, for example, the last 2 meters, of the row. Preferably, these mean orientations are parallel to each other.

[0082] The user can also define the D4 distance, which is the maximum permitted distance between a planned U-turn and the crop. Again, this is a safety margin, ensuring that the robot does not stray beyond a certain distance from the crop.

[0083] As can be seen in Figures 2 and 3A, the CDDTs 10i, IO2 are generated based on the shape or envelope 81, 82 of the plot, as well as the distances D1, D2, D3, and R (which are identified in Figure 2, which represents the generation of a turnaround path in a simple case with a rectangular map). Preferably, a CDDT is formed at a distance M1 from all the crops concerned; the CDDT can form an envelope around the plot or field at a distance M1 from the crops.

[0084] Figure 3A also shows the generation of a U-turn path IO2, but in a complex case with a herringbone shape. Once the CDDT is extracted or calculated, it is possible, particularly in a case such as that of Figure 3A, to perform a smoothing step to avoid the angle(s) causing abrupt changes in direction. The result of the smoothing is illustrated in Figure 3B.

[0085] To manage complex and / or specific situations, a user can input a CDDT (Circuit Deflection Timetable) onto a map, for example, into the robot's computer's memory, to indicate the area where the turnaround should occur; this is called a "manual" CDDT. Such a manual (non-calculated) CDDT can be located at least partially parallel to a CDDT calculated by the computer or as an alternative to such a calculated CDDT.

[0086] For example, in the case illustrated in figure 4 a manual CDDT 10' (previously entered by the user) makes it possible to avoid an obstacle 15, which would otherwise be located on the path of the calculated CDDT IO3.

[0087] In a case such as that of Figure 4, there is a choice between the manual CDDT 10' and the calculated CDDT; the choice of the CDDT to use can be automatic, for example based on one or more criteria, such as the following: presence of an intersection between the CDDT and rank N, as well as between the CDDT and rank N+1; these intersections will allow the calculation of the robot's entry and exit trajectories; and / or distance (P3; 11) > Ml? This condition allows verification that the distance between the last point P3 of rank N and the CDDT is greater than the minimum distance Ml; and / or distance (P4; 12) > Ml; this condition allows verification that the distance between the first point P4 of rank N + 1 and the CDDT is greater than the minimum distance Ml; and / or distance (P3; 11) < D4; This condition allows us to verify that, on its exit trajectory from rank N, the robot does not move away from the crop beyond the distance D4; and / or distance (P4; 12) < D4;This condition allows us to verify that, on its entry trajectory into row N + 1, the robot is not further from the crop than the distance D4.

[0088] Preferably, priority is given to the manual CDDT. If it meets the above conditions, it is selected; otherwise, the calculated or auto-generated IO3 CDDT is chosen.

[0089] Preferably, a U-turn path does not intersect one or more of the work paths.

[0090] If several turning paths are available, a turning path can be selected from among a plurality of them. For example, a manual turning path and / or a turning path that does not intersect one or more of the working paths can be chosen.

[0091] Once the CDDT(s) have been calculated and / or selected, it is possible to calculate the trajectories that will define the maneuvers the robot must perform to reach the CDDT from rank N and leave the CDDT to reach rank N+1. These calculations are preferably performed by the same computer that performed the previous calculations.

[0092] If the robot can rotate on the spot (R = 0 cm), then only points 11 and 12 can be placed as defined above. The robot moves to these points and rotates on the spot. The robot travels from P3 to 11, then from 11 to 12 along the CDDT, and then from 12 to point P4.

[0093] If the turning radius R is greater than 0 cm, a rotation on the spot is not possible. At least two maneuvering phases can then be planned: the exit phase (to leave lane N and join the CDDT) and the entry phase (to leave the CDDT and join lane N+1). Depending on the specific situation (see examples below), one or more reversing phases may be included in the exit phase, the entry phase, and / or the interchange phase.

[0094] Preferably, Bézier curves are used for calculating maneuvers. Bézier curves are parametric curves. They are defined by a set of control points, and their shape is influenced by these points. They allow the generation of a maneuver path or robot trajectory.

[0095] - which is tangent on one side to the end of rank N and to the CDDT and on the other side to the CDDT and to the end of rank N+l;

[0096] - which allows the widest possible angle of rotation while taking into account the limits imposed by the robot.

[0097] The simplest Bézier curve is the linear curve, which is a straight line between two points. Higher-degree Bézier curves (quadratic, cubic, etc.) use three, four, or more control points.

[0098] Such a curve begins at the first control point and ends at the last control point. It is contained within the polygon formed by the control points (what is called the Bézier "hull"). An affine transformation (translation, and / or rotation, or scaling) of the control points transforms the curve in the same way.

[0099] Within the framework of the present invention, Bézier curves allow for the tracing of rounded trajectories during maneuvers to exit rank N, reach the CDDT, then exit the CDDT and reach rank N+1. For this purpose, it is possible, for example, to fix four control points: two at the beginning (PI and B1 in Figures 5A and 5B, 6A and 6B) and two at the end (B2 and B3 in Figures 5A and 5B, 6A and 6B) of the curve, so as to be tangent at the exit and the end, while respecting the radius of curvature; the control points can be positioned according to the radius; for example:

[0100] - point PI is fixed at a distance R from the CDDT and point B1 at an arbitrary distance from point Pl (B1 being located between PI and 11), for example a few centimeters away, for example even 5 cm away;

[0101] - point B2 is fixed at a distance R from point 11 on the CDDT and point B3 at an arbitrary distance from point B2 (B2 being located between B3 and 11), for example a few centimeters away, for example even 5 cm away;

[0102] Segl is the segment defined by [P3, PI] and Seg2 is the segment defined by [P4, P2]. If the angle between Segl and the CDDT segment at intersection 11 is less than a limiting angle (below which the robot can rotate), for example 100°, the radius of the trajectory is compatible with the machine's rotation capacity. This is the case illustrated in Figures 5A and 5B: Figure 5A shows the points Pl, Bl, 11, B2, B3, while Figure 5B shows the trajectory Ti calculated from these points using Bézier curves; this trajectory will connect the exit row and the 180-degree turn path IO4.

[0103] Conversely, if the angle between Segl and the CDDT segment at intersection Il is greater than the limiting angle, for example 100°, a reversing maneuver can be performed to ensure that the turning radius does not exceed the machine's specifications. This is illustrated in Figures 6A and 6B: in these figures, points B2 and B3 are placed on a straight line passing through 11 and located within the limit of the chosen angle (here, 100°). The robot will therefore follow a trajectory that will allow it to reach the CDDT, first by joining the line connecting 11, B2, and B3, and then by performing a reversing maneuver along a trajectory T. r to position oneself along the CDDT and then by advancing along the latter.

[0104] For the trajectory which connects the CDDT and rank N+l, the same calculations and considerations are applied, but with points 12 and P4.

[0105] Finally, the calculated maneuvers and the CDDT can be combined. Thus, the exit trajectory of rank N can be linked to the CDDT, and the CDDT to the entry trajectory of rank N+1; this forms a complete U-turn with a path starting at P3 and ending at P4. To link the two maneuvers (and therefore the robot's exit trajectory with its entry trajectory), the selected CDDT will be followed. This is shown in Figure 7: the robot first follows an exit trajectory Ti, then follows the CDDT lOe, and finally follows the entry trajectory T2.

[0106] If the two maneuvers intersect, as illustrated in Figure 8, a reverse movement phase T rThis separates the movement along the exit trajectory Ti from the movement along the entry trajectory T2. The maneuver explained in relation to this figure can also be applied when the distance X between the exit rank N and the entry rank N+1 is zero, that is, when the entry rank is identical to the exit rank. In other words, the robot then performs a reverse movement between the trajectory that allows it to exit the rank in which it has just worked and the trajectory that allows it to re-enter that same rank, to work there again.

[0107] Complex cases (for example with rows arranged in herringbone, as illustrated in figures 9A, 9B and 10) can be handled automatically: if a card is in herringbone and the exit maneuver is already done in three phases (including a reverse phase), the assembly will be done in the same way as described above, this is the case illustrated in figures 9A and 9B.

[0108] If the maneuvers intersect, as illustrated in Figure 10, an additional reverse phase can be added; there is then a Tri reverse phase in the exit trajectory and a T reverse phase. r 2 for the entry trajectory and, between these 2 reverse phases, the following of the U-turn path IO2, which is herringbone as in the case of Figure 3A. It can also be noted that Figure 10 represents the case where rank N+1 is not the rank immediately adjacent to rank N.

[0109] The robot's exit trajectory then includes a forward movement phase Ti, a backward movement phase, and a movement phase along the CDDT.

[0110] The robot's entry trajectory then includes a movement phase along the CDDT, a T phase r i of backward movement and a T2 phase of forward movement.

[0111] For cases with a radius R of 0 cm (the robot can perform a rotation on the spot), the calculation remains the same (but there is no need to perform a calculation with Bézier curves); however, the maneuvers are limited only to an angle at the intersections: thus, in figure 11, the robot joins the CDDT IO2, performs a rotation at point 11, follows the CDDT, then performs a rotation at point 12 to join rank N+l.

[0112] A method according to the invention may implement a validation phase of an exit trajectory at rank N and then an entry trajectory at rank N+1. Such a validation phase may implement one or more of the following criteria:

[0113] - checking the distance of the turnaround relative to the crops (is this distance less than D4?); - and / or checking the maximum angles of the path to ensure that, depending on the turning radius, the robot can follow the trajectory;

[0114] - and / or, for robots that do not allow for reverse movement (this may be the case, for example, of a straddle robot), verification that no reverse movement phase has been added during the assembly of the different trajectories.

[0115] If this phase leads to an invalidation of the planned trajectories, then an error is reported, indicating that an area of ​​the field or plot needs to be adapted to the configuration and / or characteristics of the robot.

[0116] A robot according to the invention may be equipped with:

[0117] - means for guidance by a "GPS" or "GNSS" type guidance system;

[0118] - and / or an inertial measurement unit (IMU); guidance is then preferably based on a line drawn on the ground. GNSS data acquisition can be performed on the top of the robot;

[0119] - and / or one or more rotation and / or position sensor(s) of one or more robot motor(s).

[0120] These means allow the robot's computer to compare the trajectory it actually follows with the trajectories calculated according to the invention. It can thus correct the trajectory if it deviates from such a calculated trajectory.

[0121] In a method according to the invention, a preprocessing step can be implemented to process a working map of an agricultural plot comprising at least two rows of crops. This preprocessing step may include defining a boundary around the plot, encompassing the crop rows. It is thus possible to define an end-of-row zone between the ends of the crop rows and the plot boundary, a zone within which at least part of at least one turning path and / or one or more exit paths from row N and entry paths into row N+1 may be located.

[0122] A method according to the invention may further include one or more of the following steps: - a step or substep for determining an auxiliary half-turn comprising substantially straight sections and turns made substantially on the spot, when a half-turn path as a function of the minimum steering angle of the agricultural robot cannot be determined with a Bézier curve;

[0123] - and / or a step of calculating the orientation of the agricultural robot at the exit of the first row with respect to a mean line of the first row, including a first sub-step of calculating a distance Ml, being the shortest distance between the end point of the first row and the turnaround path of the agricultural robot, from the geometric parameters of the agricultural robot;

[0124] - and / or a step of calculating the orientation of the agricultural robot at the entrance of the second row, the orientation of the agricultural robot at the entrance of the second row with respect to an average line of the second row being substantially identical in absolute value to that calculated during the step;

[0125] - a step or substep of determining two target points, a first target point and a second target point, and the determination of a first turnaround path segment between the exit point of the first row and a first target point, of a third turnaround path segment between the second target point and the entry point of the second row, the second segment being calculated using a Bézier curve as a function of a minimum steering angle of the agricultural robot.

[0126] An agricultural robot 100 to which the invention can be applied is schematically represented in figure 12.

[0127] It includes wheels 16, 18, a motor (not shown in the figure), and means of transmission between the motor and the wheels.

[0128] It includes the features already described and can be equipped with:

[0129] - a number of rotation sensors and / or position sensors 140i, 1402 -, 140 n which allow us to measure one or more of the parameters already mentioned above;

[0130] - and / or means (including an antenna) for GNSS guidance or

[0131] GPS. Data measured using sensors 140i, 1402, 140 n can be transmitted to a 120 computer or an on-board computer.

[0132] This includes, for example (Figure 13), a central unit, which itself comprises a microprocessor 56, a set of non-volatile memories and RAM 57, peripheral circuits, all these elements being coupled to a bus 55. Data can be stored in the memory areas, in particular data to implement a method according to the present invention, for example:

[0133] - the geometric data DI, D2, R of the robot and / or tool,

[0134] - and / or data such as user-defined D3 and / or D4 distances,

[0135] - and / or a map (or work map) of the agricultural plot comprising several rows of crops and on which the robot must work and / or specific points, for example points P3 and P4 of rows of this plot).

[0136] The memory area(s) form(s) a computer-readable recording medium for implementing a process according to the invention, or containing instructions that, when read by a computer, enable the implementation of a process according to the invention. Other types of media may include a USB key or any other type of data storage medium used in computing, which, when read by a computer, enables the implementation of a process according to the invention. The robot's computer can therefore be programmed or configured to implement a process according to the invention. Means 59 will manage the input data flow (and in particular from sensors 140i, 1402 ..., 140 n ) and output, and towards the various components of the robot. These means of receiving and / or transmitting wireless data can also be provided.

[0137] The above data can be processed by a method according to the invention. The calculations can be performed by the robot's computer. Commands are then applied to the robot's components (motor and then transmission) based on these calculations.

[0138] Alternatively, a method according to the invention can be implemented by a computer other than that of the robot, provided with the aforementioned data. The trajectories and paths calculated by this other computer can then be loaded into the memory of a robot's computer.

[0139] This other calculator or computer may have the same type of elements as described above in relation to Figure 13. The data mentioned above may be provided.

[0140] The invention proposes a method for generating U-turn trajectories, which can be applied to many different robots, for example 4-wheel drive or "tracked" type, etc.

[0141] Such a process is: - configurable: it takes into account the dimensions of the vehicle, the tools, the turning radius, as well as any possible margins of travel;

[0142] - adaptive: it is suitable for complex cases, with the possibility of being manually adjusted for very specific areas or areas with obstacles.

Claims

DEMANDS 1. A method for determining a U-turn trajectory for an agricultural robot (12), between a first row (N), called the exit row N, and a second row (N+l), called the entry row N+l, this method being implemented by computer, said agricultural robot comprising one or more geometric parameter(s) and operating on a field or agricultural plot comprising a row crop area mapped as a working map, said field or agricultural plot comprising a plurality of consecutive crop rows, including at least a first row and a second row, the method being characterized in that it comprises: a) - a calculation step of at least one U-turn path (10i, IO2, IO3, 1C) that the robot will follow for at least part of the U-turn maneuver to exit the exit row N and enter the entry row N+l, b) - a calculation step,of at least one output trajectory (Ti) between the output rank N and a U-turn path and of at least one input trajectory (T2) between this U-turn path and the input rank N+1, c) - a step of assembling the trajectories thus calculated with the U-turn path to form a U-turn trajectory from rank N to rank N+1, the process further comprising a step of verifying the validity of the U-turn trajectory obtained, this verification of the validity of the U-turn trajectory being based on the number of intersection points between the U-turn path and the working paths.

2. Method according to claim 1, the turnaround paths being generated according to the shape of the field or plot and at least one geometric parameter(s) of the robot.

3. Method according to claim 1 or 2, calculating in step a) at least one U-turn path (10i, IO2, IO3, 1C) that the robot will follow during at least part of the U-turn maneuver to exit row N and enter row N+l input being carried out according to the contours of the plot, the dimensions of the robot, the bulk of the tool and the space allowing to carry out a maneuver.

4. A method according to any one of claims 1 to 3, wherein step b) is carried out using Bézier curves.

5. Method according to the preceding claim, wherein the Bézier curves have 4 control points.

6. A method according to any one of claims 1 to 5, wherein the minimum distance (Ml) between a U-turn path and the last point of the output row N and / or the first point of the input row N+l is further calculated.

7. Method according to claim 6, wherein: the distance between the last point (P3) of the output row N and the turnaround path is evaluated and compared to the minimum distance (Ml); and / or the distance between the first point (P4) of the input row N + l and the turnaround path is evaluated and compared to the minimum distance Ml.

8. A method according to any one of claims 1 to 7, wherein step b) comprises the calculation: - of the intersection (11) between the U-turn path and the direction of the exit row N; - and / or the intersection (12) between the U-turn path and the direction of the entry row N+l.

9. A method according to any one of claims 1 to 8, in which it is evaluated whether, on its exit trajectory from the exit row N and / or on its entry trajectory into the entry row N + l, the robot does not move away from the crop beyond a safety distance (D4).

10. A method according to any one of claims 1 to 9, wherein step b) is carried out with a U-turn path entered by a user instead of the U-turn path calculated in step a).

11. A method according to any one of the preceding claims wherein step b) is a function of a steering angle of the agricultural robot.

12. A method according to any one of the preceding claims wherein the exit trajectory between the exit rank N and a U-turn path and / or the entry trajectory between this U-turn path and the entry rank (N+1) includes at least one robot retreat phase.

13. A method according to any one of the preceding claims, wherein the turnaround path includes at least one robot retreat phase between the exit path between the exit rank N and a turnaround path and the entry path between this turnaround path and the entry rank (N+1).

14. A method according to any one of the preceding claims, wherein the U-turn trajectory comprises at least one part: - tangent on one side to the end of row N of exit and to the U-turn path and / or to the U-turn path and to the end of row N+l of entry; - and / or which allows the widest possible angle of rotation while taking into account the limits imposed by the robot.

15. A method according to any one of the preceding claims wherein the exit trajectory between the exit rank N and a U-turn path and the entry trajectory between this U-turn path and the (N+l) entry rank intersect.

16. A method according to any one of the preceding claims, comprising selecting a U-turn path from a plurality of U-turn paths.

17. Method for moving an agricultural machine (12) comprising: - the determination of a U-turn trajectory according to a method according to any one of the preceding claims; - a step of transmitting orders to control means of the agricultural robot for the execution of the U-turn trajectory determined in the previous step by the agricultural robot; - the movement of the agricultural machine (12) along said turning trajectory.

18. System (120) for determining a half-turn trajectory of an agricultural machine (12), between a first (N) row, called exit row N, and a second row (N+l), called entry row N+l, comprising electronic means configured or programmed to implement a method according to any one of claims 1 to 16.

19. Agricultural robot (100) comprising wheels (16, 18) or tracks (17), wheel or track control means, advancement means, enabling the machine to advance in a main direction of advancement, a computer (120), one or more processing tool(s) (14), means for moving the processing tool(s), the computer being configured or programmed to implement a process according to one of claims 1 to 16.

20. Agricultural robot according to claim 19, the tool being of the type hoe, and / or seeder, and / or inter-row cultivator, and / or weeding finger, and / or clod-breaking disc, and / or notched disc, and / or brush, and / or rigid tooth, and / or tine harrow, and / or opening share, and / or leaf guard, and / or sprayer.

21. Agricultural robot according to claim 19 or 20, of the wheeled type (16, 18) or tracked (17) and / or of the "straddle" type of crops or of the inter-row type.

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