Method and device for classifying boundary sections of an agricultural area

Abstract

A method is described for classifying boundary sections of an agricultural area (1, 31, 41) with respect to a designated reference axis (2, 32, 42) of the agricultural area (1, 31, 41) as a side section and / or headland section, wherein the reference axis (2, 32, 42) characterizes a preferred processing direction, wherein a headland section marks a part of an agricultural area (1, 31, 41) or its boundary, which is particularly suitable for carrying out a turning operation during processing of the area with an agricultural machine (102), wherein the method can be carried out using a digitally recorded map of the agricultural area on a PC (104, 105, 108) or terminal (103) of an agricultural machine (102) or a mobile device, wherein the outer boundary of the agricultural area (1, 31, 41) is approximated by a closed polygonal line, wherein a reference axis (2,32, 42) for defining a preferred processing direction of the agricultural area (1, 31, 41) is stored in the PC, terminal, or mobile device. The minimum angles enclosing the sections of the polygon and the reference axis are determined, as well as a first limit angle (3, 33, 43) is established, and those sections of the polygon that enclose an angle with the reference axis that is smaller than the limit angle (3, 33, 43) are classified as side sections.

Description

The invention relates to a method according to the preamble of claim 1 and to a corresponding agricultural terminal.The working of an agricultural area with an agricultural machine is generally carried out in rows. This means that with an agricultural implement, for example a plough, the field is processed along parallel or approximately parallel lines, the distance of which depends on the working width of the implement. In order to be able to carry out this work as efficiently as possible, the parallel lanes are increasingly displayed to the operator on a terminal or other device, so that the operator can steer the device as precisely as possible along the lanes provided. Automatic steering along the parallel lanes is also conceivable.The position, orientation and geometry of the lanes depends primarily on the working width of the machine and the field geometry. In particular, it is of great importance for the efficiency of the working of the agricultural surface that the time-consuming, but typically necessary turning operations of the agricultural machine are carried out as efficiently as possible and the number of turning operations is minimized.The turning operations are normally carried out in a region of the field which is initially cut out during the processing of the surface. Typically, there are two (sometimes more than two) such areas found on opposite sides of the agricultural area. The agricultural host thus processes the field strip by strip and turns it in each case shortly before it reaches the end of the surface, wherein he interrupts the respective processing process during the turning process.In order to enable the planning of the front end as efficiently as possible, it has been proposed to automate the planning of the front end position on the agricultural area.EP 2 257 889 B1 proposes for this purpose defining a preferred machining direction and defining so-called secondary reference paths which run parallel to the preferred machining direction. It is now checked in each case whether a defined limit angle is undershot at the intersection of the secondary reference paths with the boundary of the agricultural surface and, in this case, a front end is placed at the location. Here, the secondary reference paths are offset by a fixed distance. This can be, for example, the working width of the agricultural machine, the machine width or some other value.It is disadvantageous in the known prior art that the position of the front weights or side sections of the agricultural area depends directly on the respective distances and positions of the reference paths and local circumstances and orientations of the boundary of the agricultural area have a direct effect on the classification as front weight.It is the object of the present invention to eliminate the disadvantages of the prior art and to provide an optimized method which is capable in particular of defining front and side sections of an agricultural surface on the basis of the field geometry.This object is achieved by the characterizing features of claim 1. A preferred machining direction is thus defined for determining one or more side sections and / or front end sections of an agricultural area. This can be defined by the user or in particular provided by a separate method. The outer boundary of the agricultural area in question is approximated by a closed polygonal path, wherein the length and direction of the sections of the polygonal path can be determined. According to the invention, the minimum angle is now determined which the sections of the polygonal line include and the reference axis, a first critical angle is defined and those sections of the polygonal line are classified as side sections which include an angle with the reference axis which are smaller than the critical angle. In this case, side sections are those sections of the polygon course which do not serve as a front end, i.e. in the immediate vicinity of which no turning process is to take place during the working with an agricultural machine or onto which the lanes planned for the working do not meet perpendicularly or predominantly perpendicularly. The present method therefore enables lateral sections of an agricultural area to be defined in an automated manner. For this purpose, only a preferred orientation is specified during the processing, which orientation can also be determined by a separate, automated method. It is also predetermined how large the angle is to be, which lateral sections and the preferred machining direction are allowed to enclose at most. Determination of the minimum angle here means that, in the case of the two possible angles which can indicate the relative orientation of two straight lines, the smaller is used for the determination of the side sections or front end sections. In comparison with the prior art, this method makes it possible not only to define the sections on the basis of an orientation relative to a reference axis, but also to take into account the orientation of adjacent sections. In this way, it is advantageously made possible, for example, for a side section which has a comparatively large angle with respect to the reference axis but a small angle with respect to the adjacent section likewise to be classified as a side section, with the result that trains of sections in which the orientation changes only slightly from one section to the next are classified in the same way.According to an advantageous development of the invention, a second and / or a third critical angle is now defined and those sections of the polygonal path which adjoin at least one side section are classified as side sections which enclose with all adjacent side sections a minimum angle which is smaller than the second critical angle and / or enclose with the reference axis a minimum angle which is smaller than the third critical angle. In this way, sections which adjoin lateral sections can now preferably be classified as lateral sections.This can be done, for example, by considering the relative orientation to adjacent side sections, so that preferably a plurality of contiguous side sections are classified. For this purpose, the second critical angle can be selected to be relatively large, for example. Additionally or alternatively, the orientation to the reference axis can be viewed. A preferred classification of a plurality of contiguous side sections can now be effected in that the sections adjacent to already classified side sections may have a greater angle with respect to the reference axis than side sections already classified in the first step in that the third critical angle is selected to be correspondingly greater than the first critical angle. In a preferred embodiment, the method described above is repeated for all newly classified page sections, so that it is not possible incorrectly to miss a classification of sections as a page section.In an advantageous development, all sections not classified as side sections are now classified as front end sections. Thus, it is determined which portions of the agricultural area appear to be particularly suitable for turning with the agricultural machine during the working. A front end section is a section onto which the lanes run preferably approximately vertically during the working of the agricultural surface and in the immediate vicinity of which preferably turning operations are carried out during the stripwise working of the agricultural surface.In an advantageous development of the invention, a vectorial directional information item is assigned to the reference axis and the respective sections of the polygonal train are likewise assigned a vectorial directional information item in such a way that the end point of a section is in each case the starting point of the adjacent section and those side sections are classified as the right side which enclose an angle greater than or equal to 90° and less than 270° with the reference axis and the remaining side sections are classified as the left side. Thus, the right and left sides of the agricultural area are separated and thus made distinguishable. The mutually opposite side sections are therefore marked as the right and left sides. It should be noted here that the measuring direction must be fixed and constant, for example in the clockwise direction.In an advantageous development of the invention, a vectorial directional information item is assigned to the reference axis and the respective sections of the polygon train are likewise assigned a vectorial directional information item in such a way that the end point of a section is in each case the starting point of the adjacent section and those front end sections are classified as upper front end which enclose an angle greater than or equal to 0° and less than 180° with the reference axis and the remaining front end sections are classified as lower front end. It should also be noted here that the measuring direction must be fixed and constant, for example in the clockwise direction. Thus, in this way, the front end sections are likewise divided into upper and lower front end sections which are opposite one another with respect to the agricultural surface, and upper and lower front end are thus made distinguishable.In an advantageous development, in the case of adjacent sections which are characterized by a change in the classification from right side to left side or vice versa and also an angle between the sections facing the interior of the surface of less than 180°, the classification is changed to upper front end or lower front end at least in one of the two sections. Thus, preferably no direct change from right side to left side should take place in adjacent sections if the angle between these two side sections, which faces the interior of the field, is less than 180°, since this would promote entry into wedges of the agricultural surface without a present front end. The agricultural host would therefore have to enter a wedge of the surface (angle <180°), wherein none of the relevant sections would be defined as a front end. Thus, it would be unclear to the agricultural host at which position within this wedge surface of the agricultural surface the turning operation should be carried out. The prior art does not put such a consideration in a transition from left side section to right side section, which leads to missing headland sections and thus to an unfavorable field or lane planning.In this case, according to a preferred development,the size of the respective angle of the sections to the reference axisthe length of the respective sectionsthe magnitude of the longitudinal component of the respective section transversely to the reference axisThe criterion used is which of the two sections is reclassified to a preland section. This enables the most efficient possible processing of the agricultural surface. If, for example, the magnitude of the angle of the respective section with respect to the reference axis is used, a front end section can be formed which is as perpendicular as possible to the reference axis. Furthermore, the length of the relevant section can be taken into account, so that a maximum or short front end section is produced depending on the requirement. For example, it may be desired to adjust the length of the two opposing front end sides. Alternatively, only the length of the transverse component relative to the reference axis can be taken into account in the selection of which section is reclassified in order to reclassify a section to the present party which has a transverse component as long as possible or else short as possible relative to the reference axis. For example, a portion which is particularly long but includes a very small angle to the reference axis may have a smaller transverse component than a comparatively short portion which has a large angle to the reference axis.In an advantageous development of the invention, the method is applied to a second surface within the agricultural surface, which marks a recess, in particular an obstacle, within the agricultural surface, wherein the second surface is likewise approximated as a closed polygonal line. Thus, in an advantageous manner, a classification of the sections of a boundary of a recess can likewise take place, wherein the boundary marks a recess within an agricultural area in this case. This can be, for example, an obstacle such as a tree, a power mast or the like. It can also be, for example, a water surface or the like within the agricultural area. A plurality of recesses within an agricultural area are also conceivable. The sections of the boundary of this recess can be divided in an analogous manner into lateral sections and front walls. The classification of the sections into the right side and the left side can also be carried out in a completely analogous manner.Preferably, however, the classification into upper and lower front weights will be carried out differently for the delimiting of a cutout by also assigning vectorial directional information to the respective sections of the polygon course in such a way that the end point of a section is in each case the start point of the adjacent section, those sections of the second surface which have not been classified as a side region, thus preferably as a front weight region, the angles of which with respect to the reference axis are greater than or equal to 0° and less than 180°, being classified as a lower front weight and the remaining sections not classified as a side region being classified as an upper front weight. It is thus ensured that an upper front end is opposite a lower front end without a cutout being found in the agricultural area therebetween. In other words, the lower portions of the recess boundary front end are classified as the upper front end because they are opposed to the lower front end of the outer boundary of the agricultural area. Also, the upper portions of the recess boundary front end are classified as lower front ends because they are opposed to the upper front end of the outer boundary of the agricultural area.In an advantageous development of the invention, for delimiting the recess within the agricultural area, in the case of adjacent sections which are characterized by a change in the classification from the right side to the left side or vice versa and also an angle between the sections facing the inner surface of more than 180°, the classification is changed to the upper front end or lower front end at least in one of the two sections, wherein one or more of the following criteria can be used to determine which of the two sections is reclassified:size of the respective angle of the sections to the reference axislength of the respective sectionssize of the length component of the respective section transversely to the reference axis.It is thus also provided for the recesses that, in the case of directly adjacent side sections, a reclassification of one of the sections can take place with a change from right to left. In this case, reclassification is provided if the angle facing the recess is greater than 180°. This means that a front end is provided with rather wide recesses, whereas a front end does not necessarily have to be provided with rather narrow recesses, since these recesses sometimes do not have to be turned in front of them, but rather can be passed by simple passage during the machining, which is particularly advantageous since time-consuming turning operations are avoided. The reason for this procedure can be seen in the fact that, in the case of such a geometry, in which the angle facing the recess is greater than 180°, a wedge-shaped geometry results within the surface into which the agricultural machine has to be driven. Accordingly, the placement of a preview here is advantageous.In an advantageous development of the invention, at least one lane for processing the agricultural surface is planned by means of an agricultural working machine, wherein the at least one lane runs at least approximately between two mutually at least approximately opposite front end sections of the agricultural surface and / or at least approximately parallel to at least one of the side sections of the agricultural surface. The working of the agricultural surface is thus planned according to the created front end and / or side sections by means of one or more preferably parallel lanes, wherein these preferably run between mutually opposite front end sections, in particular upper and lower front end, and furthermore preferably at least approximately parallel to one or more of the side sections.In an advantageous development, a limit value is defined for the minimum ratio of the sums of the lengths of the upper and lower front end sections and / or for the minimum ratio of the sums of the lengths of the upper and lower front end sections transversely with respect to the reference axis, and if this limit value is undershot, the length of the longer front end is shortened by reclassifying front end sections into side sections or, conversely, the length of the shorter front end is increased by reclassifying side sections into front end sections. This ensures that the lengths of the two front end sides do not become miscompetent. Preferably, the front end sides, i.e. the total length of upper and lower front end, are approximately the same length, since the number of lanes which end at the respective front end side is preferably the same. It can also be provided during the observation that instead of the sum of the total lengths of the sections, the sum of the lengths of the sections with respect to a specific direction, for example the transverse component perpendicular to the reference axis, is observed, since the reference axis at least approximately defines the direction of travel during the machining and this is preferably perpendicular to the front end sections.There is also provided an agricultural machine terminal for performing any of the methods described above. The terminal is designed as an operating terminal and has a display and preferably an input device, for example in the form of buttons or a touchscreen. The method according to the invention can be carried out directly on the terminal or on a job computer connected to the latter or on an external computer and the results, for example the position of the headland sections or the position of the lanes, can be displayed only on the touchscreen.According to a preferred embodiment, the geographical data of the agricultural area are stored on the terminal and can thus be processed directly by the terminal. For example, the outer boundary of the agricultural area can be approximated by a closed polygon sequence by means of an algorithm stored in the terminal, to which the method according to the invention is then applied by the terminal.According to a possible development, at least one lane to be worked is displayed together with the current position of the agricultural machine on a display of the terminal. The agricultural host thus receives direct feedback with respect to the own position relative to the lane to be machined, so that deviations can be corrected directly. Alternatively or additionally, it is indicated, for example by corresponding arrows on the display of the terminal, in which direction the agricultural host must steer in order to keep or turn a course along the lane to be worked.In an advantageous development, the terminal is designed to determine a lane system as a function of the classified sections and to adapt the working width of the agricultural machine as a function of the current position of the agricultural machine and of the processed lane and / or of the lane to be subsequently processed. The lane system is generated in such a way that the lanes extend at least predominantly parallel to the reference axis between the front end sections. Lanes are thus determined by the terminal based on the geometry of the agricultural surface and the classified sections in such a way that the lanes preferably run parallel or approximately parallel to the reference axis. A successive change in the orientation of adjacent lanes, which is caused and necessary, for example, by the contour of the agricultural surface, can now be advantageously achieved by adapting the working width, for example, in the form of a cut width adjustment on the plough, as a function of the current position. For this purpose, corresponding actuators on the agricultural machine are preferably controlled for setting the desired working width. As a result, the following lane to be processed can be defined accordingly, so that the lane receives the desired orientation. In this way, trapezoidal surfaces, for example, can be machined completely and without gaps.In a possible development, the terminal or a control system connected to the terminal at least partially autonomously steers the agricultural machine, so that the agricultural surface is processed along the previously planned lanes.Further aspects and embodiments of the invention are evident from the figures and the exemplary description, in which FIG. 1 shows an agricultural machine system, FIGS. 2 to 6 show the application of the method according to the invention to a schematically illustrated boundary of a first agricultural area, FIGS. 7 to 9 show the application of the method according to the invention to a schematically illustrated delimitation of a second agricultural area, FIG. 10 shows the application of the method according to the invention to a schematically illustrated delimitation of a third agricultural area, and FIG. 11 shows the application of the method according to the invention to a schematically illustrated delimitation of a fourth agricultural area.An agricultural machine system comprising a terminal 103 according to the invention is shown in Fig. 1. The agricultural machine system here comprises a tractor 101 and a plough 102 coupled to the tractor. The coupled plough can be seen here by way of example. Any other agricultural machine for working an agricultural surface may also be attached to the tractor 101. The agricultural machine system can also be designed as a self-propelled agricultural machine system, for example a self-propelled syringe or combine harvester.The tractor 101 has a terminal 103 which can display information to the driver of the tractor 101 by means of a display device, in particular information of the agricultural machine 102 and of the tractor, such as position, speed etc., can be displayed and operating parameters, for example the working width and / or working depth, can be changed. For this purpose, the terminal 103 has operating elements in the form of switches, buttons and / or, in particular, a touch-sensitive screen. The terminal is in particular connected to one or more job computers 104, 105, which can be located on the tractor and / or the coupled agricultural machine. The data connection between the job computer 105 of the agricultural machine 102 and the job computer 104 of the tractor is preferably effected via a standardized data connection 106, in particular a so-called ISOBus interface. Alternatively, the terminal 103 can also be connected directly via the bus system, in particular the ISOBus, to the job computer 105 of the agricultural machine 102. Via this bus system, information of the agricultural machine, for example set actual values or sensor data, is transmitted to the job computer 104 or the terminal 103. Control commands from the job computer 104 or terminal 103 are also transmitted in the opposite direction to the job computer 105 of the agricultural machine 102. To execute the control commands, the job computer 105 is connected to actuators and sensors via a data connection, for example to an actuator 109 for setting the section width of the plough 102. It is also conceivable for the job computer 105 of the agricultural machine 102 to transmit control commands to the tractor 101 via the bus system 106 within the scope of what is known as a TIM application (Tractor Implement Management). By means of the coupled machine 102, for example, a control command for reducing the speed or for raising a three-point power lifter for reducing the working depth can be carried out in this way. Such a measure can be triggered, for example, by corresponding sensor signals on the agricultural machine 102.The terminal 103 is now designed to determine a preferred machining direction in the form of a reference axis on the basis of a stored map of the agricultural surface to be machined. Alternatively, the reference axis can also be input or determined by traversing and recording a route.The field boundary stored in the card in the terminal 103 is now preferably automated and divided into sections of a polygonal line by means of a method known per se. The sections are then classified into headland sections and side sections based on their relative orientation to the reference axis and their relative orientation with respect to each other, as explained in detail below.A lane system is now determined on the basis of the classified sections of the polygon and the agricultural surface along this lane system is processed. In a particularly preferred embodiment, the terminal is connected to a GPS receiver 107, and the working width of the agricultural machine 102, here of the plough, is set automatically as a function of the distance of the lanes of the lane system determined by the terminal at the location of the machine.The modules for calculating the lane system are executed either on the terminal 103 or on the job computer 104 connected to the terminal, and the lane system is then merely displayed on the terminal. It is also conceivable for the lane system to be ascertained on an external data processing system 108 and for the lane data and field coordinates to be transmitted to the terminal 103 or the job computer 104 by means of a data connection or a data carrier.The modules for planning the lane system are therefore executed on the terminal 103 or the job computer 104 or executed on the data processing system 108 and the lane system is made available to the job computer 104 or terminal 103. The agricultural surface is worked along the laid lane system. For this purpose, it is provided that the lane system is displayed on a screen of the terminal. The user can now steer the tractor 101 along the displayed lanes and edit the field accordingly. For this purpose, the cutting width of the plough or working width of the agricultural machine is also adapted in accordance with the distances of the lanes of the lane system at the current position.As already mentioned, it is optionally provided that the machine system automatically determines and sets the working width of the agricultural machine in accordance with the lane spacing at the current position of the machine system. For this purpose, corresponding control commands are transmitted from the terminal 103 or the job computer 104 to the job computer 105 of the agricultural machine 102, whereupon the job computer 105 in the present example sets the working width of the plough 102 by means of the actuator 109 if necessary. The automatic setting of the working width can be realized for any agricultural machines which can be controlled by the tractor 102 via a data connection; in particular, the working width of sowing machines, field sprayers or fertilizer spreaders can be adapted to the local conditions in this way.In an advantageous development, it is likewise conceivable for the agricultural machine system to partially or fully autonomously process the agricultural surface along the planned lane system. For this purpose, steering commands and / or control commands for adapting the speed are output by the terminal 103 or the job computer 104, in addition to the control commands to the job computer 105 of the agricultural machine, so that the tractor 101 processes the agricultural surface along the lane system. The turning processes at the end or at the beginning of a respective lane can also be automated in this way.The agricultural surface 1 is illustrated in FIG. 2 as a closed polygonal line. This can correspond identically to the real shape of the agricultural area or can be approximated to the real shape of the agricultural area by means of a mathematical approximation method.A reference axis 2 marks the preferred machining direction. This reference axis can be provided by a separate method or can be manually defined by the agricultural host, for example by input of corresponding direction data at an operating terminal. Alternatively, a distance can also be recorded by traversing and recording a so-called AB line between two points A and B and stored as a reference axis. For this purpose, a corresponding terminal or a job computer is connected to a position receiver.The method according to the invention now provides for classifying page sections. For this purpose, as shown in FIG. 3, a first critical angle is defined relative to the reference axis, in the case of which a section of the polygonal path is to be classified as a side section when the latter is undershot. In the present example, this angle 3 is, for example, 10°. Since the sections 4 and 5 run parallel to the reference axis, they are thus classified as side sections. In contrast, the angle 12 between reference axis 2 and section 6 and the angle 13 between reference axis 2 and section 7 are greater than the limit angle 3, so that these sections are not initially classified as a side section. This applies analogously to sections 8, 9, 10 and 11.In a second step, as shown in FIG. 4, a second and a third critical angle 14 are now considered with respect to the sections 6, 7 and 11 adjacent to the sections 4 and 5 already classified as lateral sections. Here, for the comparison with the second critical angle, the angle between the respectively directly adjacent sections is considered. For comparison with the third critical angle, on the other hand, the angle between the respective section and the reference axis is analyzed. In the present case, the second and the third critical angle 14 are identical. However, these can just as well be angles of different sizes.The angle between the section 6 and the reference axis is first compared with the third critical angle 14. In the present case, the third critical angle 14 is greater than the angle 12, so that the section 6 is classified as a side section.Analogously, it is checked for the section 7 whether the angle to the reference axis 13 is smaller than the third critical angle 14. Since this condition is satisfied, the section 7 is also classified as a side section. The angle of the sections 4 and 5 to the section 11 is, on the other hand, in each case greater than the critical angle 14, so that the section 11 is not classified as a side section.In the next step corresponding to FIG. 5, a consideration of the sections 8 and 9 is now carried out. The angle 15 between the section 8 and the reference axis 2 is greater than the third critical angle 14, so that the section 8 is not initially classified as a side section. It is now checked whether the angle 16 between the section 6 and the section 8 is smaller than the second critical angle. Since this condition is satisfied, the section 8 is also classified as a side section. In the present case, therefore, a reclassification of a section adjacent to a side section is carried out if the angle between this section and the adjacent side section is smaller than the second critical angle or the angle between the section and the reference axis is smaller than the third critical angle.However, it can alternatively be provided that both conditions must be fulfilled for reclassification of a section. The angle to the reference axis would then likewise be determined for sections which are not adjacent to lateral sections, and if the first limit angle were undershot, this section would be classified as a lateral section. In the case of a second section which adjoins the latter, the angle of this second section with respect to the reference axis would likewise be determined. If the angle is smaller than the first critical angle, this section is also classified as a side section. If this is not the case, a check is made as to whether the angle is smaller than the third limit angle. If this is the case, it is additionally checked whether the angle between the two adjacent sections is smaller than the second critical angle and only if the last two conditions are fulfilled is the second section likewise classified as a side section. It is of course arbitrary whether a check is first made with regard to the second or the third limit angle. The advantage of this alternative procedure is that sections which are adjacent to already classified side sections may have a somewhat greater angle with respect to the reference axis, so that trains of comparatively parallel-oriented side sections are preferably classified. However, it is prevented by means of the third limit angle to be taken into account that, in the case of a plurality of sections which each have only a small relative angle, no preview section at all is classified, because, if the third limit angle is exceeded, a section is in any case not defined as a side section.Generally, the third critical angle is greater than the first critical angle. The second and the third critical angle are preferably different from one another, but can also be identical.Further, the portion 9 adjacent to the portion 7 classified as the side portion is considered. Since the angle 17 between the section 9 and the reference axis is greater than the third critical angle 14 and the angle 18 between the section 7 and the section 9 is greater than the second critical angle, the section 9 is not reclassified as a side section.The section 10 is directly adjacent to the side section 8, but the angle between the section 10 and the reference axis is greater than the third critical angle and the angle between the section 8 and the section 10 is greater than the second critical angle, so that the section 10 is not classified as a side section.In a further step, sections 9, 10, 11 that were not classified as page sections are now classified as a headland section.It is now determined, as shown in FIG. 6, which side sections are classified as the left side and which are classified as the right side. For this purpose, directional information is assigned to the individual sections of the polygon and also to the reference axis, as can be read in FIG. 6 by means of the arrows. The end point of each section of the polygon is the beginning point of the next section. The side sections which lie in an angle range 19 relative to the reference axis, i.e. enclose an angle greater than or equal to 90° and less than 270° with the reference axis, are classified as right sides. The remaining side sections lie accordingly in an angle range 20 and are classified as the left side.Analogously, the front end sections which lie in an angle range 21 and enclose an angle with the reference axis which is greater than or equal to 0° and less than 180° are classified as upper front end and those sections which, taking into account the defined measurement direction, are located in an angle range 22 greater than or equal to 180° and less than 0° relative to the reference axis are classified as lower front end.A second embodiment, shown in FIG. 7, shows a pentagonal agricultural surface 31 with reference axis 32. According to the defined first critical angle 33 and third critical angle 39, sections 34, 35, 36 and 37 are classified as lateral sections, while section 38 is classified as a headland.If the individual sections and the reference axis are now assigned their directional information, as shown in FIG. 8, and the individual sections are classified by their orientation relative to the reference axis as left side 34 and 36 as well as right side 35 and 37 and as lower front wall 38, it follows that a left side 36 directly adjoins a right side 37. For this reason, it may be provided to reclassify one of the pages 36 or 37. Different criteria can be used for this, thus provision can be made to reclassify the longer section or to reclassify the section with the greater transverse component relative to reference axis 32. All of these criteria would in this case result in the section 36 being reclassified and therefore the left side classification changed to top will. This has the result that a respective front end side is provided on at least approximately opposite sides of the agricultural surface 31, namely the lower front end 38 and the upper front end 36. For this purpose, the length of the transverse component of the sections 36 and 37 is preferably determined and compared with the front end section 38 or its transverse component.Processing which takes place at least approximately along the reference axis 32 in at least approximately parallel lanes 39 can thus be carried out in such a way that turning processes take place in each case at or in the vicinity of the front end sections 38 and 36, as illustrated in FIG. 9. In general, provision can be made for lanes for processing the agricultural surface to be placed at least approximately along or parallel to the reference axis in such a way that the turning processes can advantageously take place at or in the vicinity of the front end sections. The lanes can be determined according to the method according to the invention by means of an agricultural terminal according to the invention or job computer of an agricultural machine and displayed on a terminal.Another application of the method according to the invention is shown in Fig. 10, wherein in a seven sided agricultural area, using the reference axis 42 and the first limit angle 43, four sections 44, 45, 46, 47 are defined as the side section. The second and third critical angles, not shown, are selected in this case such that none of the sections 48, 49 or 50 is additionally defined as a side section. Thus, three front end sections 48, 49 and 50 result. Taking into account the directional information, the sections 44 and 47 result as the left side, the sections 45 and 46 as the right side, the section 50 as the lower front end and the sections 48 and 49 as the upper front end, analogously to the exemplary embodiments described above.An application of the method according to the invention to an agricultural surface which has recesses, such as obstacles, for example, is illustrated in FIG. 11. The agricultural surface 1 with reference axis 2 is shown analogously to FIGS. 2-6, but in this case additionally with the recesses 61 and 71. A classification corresponding to the first critical angle 3 and the second and third critical angles 14 is likewise shown.The recess 61 has two left side sections 62 and 63 and two right side sections 64 and 65, wherein a left and a right side section are adjacent to each other. Reclassification into corresponding front end sections is not provided here, since the angles 66, 67 between the side sections 63, 64 and 62, 65 are each less than 180°.The recess 71 has, in contrast, a left side section 72 and a right side section 74 in accordance with the orientation of the individual sections of the polygonal line of the delimitation of the surface 71 relative to the reference axis 2 and taking into account the critical angles 3 and 14. In addition, the surface is assigned the front end sections 75 and 73. Note that, according to the present invention, the front end portion 73 is classified as the portion opposed to the front end upper portion of the boundary of the agricultural area 10 as the lower front end, and accordingly, the front end portion 75 is classified as the front end portion opposed to the front end lower portion 11 of the outer boundary of the agricultural area as the upper front end. In this way, a lower front end section is in each case opposite an upper front end section without a cutout, an obstacle or the like being located between them.The recess 61 in FIG. 11 can be passed through the agricultural machine provided for the machining without turning operation because of its shape, whereas this is not possible with the recess 71 and a turning operation must be carried out accordingly.Since the radius of curvature which is minimally traveled on during the processing with the agricultural machine depends on the type of agricultural machine, one or more of the three limit angles are preferably selected depending on the agricultural machine provided for the processing of the agricultural surface under consideration. For example, the minimally drivable curve radius of a plough being worked is very much larger than that of a cluster, so that the three limit angles are correspondingly selected to be smaller during plough than during the cluster. This has the result that, for example, during ploughing, sections are preferably classified as headland sections in comparison with the rubber and therefore, if appropriate, a comparatively large number of turning maneuvers have to be carried out.The angles considered in each case in the present application are generally to be understood as minimum angles. Thus, the angle between two straight lines having the lower value is considered. However, the larger angle could just as well be considered if required without deviating from the teaching of the invention. This is different only if the directional information of the respective sections or of the reference axis is explicitly taken into account. The reference axis is only necessary for defining a preferred direction of travel. Their position relative to the agricultural surface is thus arbitrary, so that in the exemplary embodiments no restriction results therefrom.

Claims

Method for classifying boundary sections of an agricultural surface (1, 31, 41) with respect to an excellent reference axis (2, 32, 42) of the agricultural surface (1, 31, 41) as a side section and / or a front end section, wherein the reference axis (2, 32, 42) characterizes a preferred processing direction, wherein a front end section marks a part of an agricultural surface (1, 31, 41) or its boundary which is particularly suitable for carrying out a turning operation during the processing of the surface with an agricultural machine (102), wherein the method can be carried out on the basis of a digitally recorded map of the agricultural surface (1, 31, 41) on a PC or terminal of an agricultural machine or a mobile terminal, wherein the outer boundary of the agricultural surface (1, 31, 41) is approximated by a closed polygon path, wherein a reference axis (2, 32, 32, 41) is defined by a polygonal path, 42) for defining a preferred working direction of the agricultural surface is stored in the PC, terminal or mobile terminal, characterized by the fact that the minimum angles which enclose the sections of the polygonal line and the reference axis are determined, a first limit angle (3, 33, 43) is established and those sections of the polygonal line which enclose an angle with the reference axis which is smaller than the limit angle (3, 33, 43) are classified as a side section.Method according to claim 1, characterised bydefining a second and a third critical angle (14) and classifying those sections of the polygonal line - which adjoin at least one side section, as a side section, - which enclose with all adjacent side sections a minimum angle (16, 18), which is smaller than the second critical angle and / or enclose with the reference axis (2) a minimum angle, which is smaller than the third critical angle (15, 17), as a side section.Method according to claim 2, characterized in that the method according to claim 2 is repeated for all newly classified page sections.Method according to at least one of the preceding claims, characterized byclassifying all sections not classified as side sections as front end sections.Method according to one of the preceding claims, characterized in that the reference axis (2, 32, 42) is assigned vectorial directional information, in that the respective sections of the polygonal train are likewise assigned vectorial directional information in such a way that the end point of a section is in each case the start point of the adjacent section and those side sections are classified as the right side which enclose an angle greater than or equal to 90° and less than 270° with the reference axis and the remaining side sections are classified as the left side.Method according to Claim 4 or 5, characterized in that the reference axis (2, 32, 42) is assigned vectorial directional information, in that the respective sections of the polygonal train are likewise assigned vectorial directional information in such a way that the end point of a section is in each case the starting point of the adjacent section and those front end sections are classified as upper front end which enclose an angle greater than or equal to 0° and less than 180° with the reference axis and the remaining front end sections are classified as lower front end.Method according to at least one of Claims 5 or 6, characterized in that, in the case of adjacent sections (36, 37) which are characterized by a change in the classification from right side to left side or vice versa and also an angle between the sections facing the inner surface of less than 180°, the classification is changed to upper front end or lower front end at least in one of the two sections (36, 37).Method according to claim 7, characterised in that one or more of the following criteria is used to determine which of the two sections is reclassified: - size of the respective angle of the sections to the reference axis (32) - length of the relevant sections (36, 37) - size of the length component of the respective section (36, 37) transversely to the reference axis (32).Method according to at least one of claims 1 - 5, applied to a second surface (61, 71) within the agricultural surface (1) which marks a recess, in particular an obstacle, within the agricultural surface, wherein the second surface (61, 71) is also approximated as a closed polygonal path.Method according to Claim 9, characterized in that vectorial directional information is assigned to the reference axis, in that the respective sections of the polygonal train are likewise assigned vectorial directional information in such a way that the end point of a section is in each case the starting point of the adjacent section, in that those sections of the second surface (61, 71) which have not been classified as a lateral region, that is to say preferably as a front end region, the angles of which with respect to the reference axis are greater than or equal to 0° and less than 180°, are classified as a lower front end and the remaining sections which have not been classified as a lateral region are classified as an upper front end.Method according to at least one of claims 9 or 10, characterised in that in the case of adjacent sections which are characterised by a change of the classification from right side to left side or vice versa and in addition an angle between the sections facing the inner surface of the second surface of more than 180°, at least in one of the two sections the classification is changed into upper front end or lower front end, wherein one or more of the following criteria can be used to determine which of the two sections is reclassified: - size of the respective angle of the sections to the reference axis - length of the relevant sections - size of the length component of the respective section transversely to the reference axis.Method according to at least one of the preceding claims, characterized in that at least one lane (39) for processing the agricultural surface (31) is planned by means of an agricultural working machine (102), wherein the at least one lane (39) runs at least approximately between two mutually at least approximately opposite front end sections (36, 38) of the agricultural surface and / or at least approximately parallel to at least one of the side sections (34, 35, 37) of the agricultural surface.Method according to at least one of Claims 6 to 12, characterized in that a limit value is defined for the minimum ratio of the sums of the lengths of the upper and lower front end sections and / or for the minimum ratio of the sums of the lengths of the upper and lower front end sections transversely with respect to the reference axis, and in that, if this limit value is undershot, the length of the longer front end is shortened by reclassifying front end sections into side sections or, conversely, the length of the short front end is increased by reclassifying side sections into front end sections.Terminal for an agricultural machine (102) for carrying out a method according to at least one of Claims 1-12.Terminal according to Claim 14, characterized in that the geographical data of the agricultural area are stored in the terminal (103).Terminal according to claim 14 or 15, characterised in that at least one lane (39) to be worked is displayed on a display of the terminal (103) together with the current position of the agricultural machine (102).Terminal according to at least one of Claims 14 to 16, characterized in that the terminal (103) is designed to determine a lane system as a function of the classified sections and to adapt the working width of the agricultural machine (102) as a function of the current position of the agricultural machine and of the lane being worked and / or of the lane being worked subsequently.Terminal according to at least one of Claims 14 to 17, characterized in that the agricultural machine is steered by the terminal (103) autonomously along the determined lanes (39).

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