METHOD FOR REGULATING A REAR LIFT OF AN AGRICULTURAL MACHINE

Description

[0001] The present invention relates to a method for controlling a rear power lift of an agricultural working machine according to the preamble of claim 1 and to an agricultural combination according to the preamble of claim 13.

[0002] Agricultural machines such as combine harvesters, forage harvesters, and tractors can be combined with various attachments. These attachments are attached to the agricultural machine via an interface, often the rear linkage. In this case, the focus is on agricultural combinations consisting of an agricultural machine and an agricultural attachment. The attachment is connected to the agricultural machine via the rear linkage.

[0003] Such attachments generally serve to perform an agricultural task. The primary focus here is on soil cultivation such as plowing or cultivating. What these types of soil cultivation have in common is that the attachments are usually set to a specific working depth. The success and energy consumption of soil cultivation often depend significantly on the working depth. However, this also depends on various machine parameters of the attachment and the agricultural machine, especially the rear power lift.

[0004] These days, rear linkage adjustments usually have to be made manually by the user. The user can specify a target position of the rear linkage relative to the tractor using position control, or indirectly a target tractive force using draft control, or a mixed factor between draft and position control. A maximum permissible slip can also be additionally specified using slip control. However, efficient adjustment of the rear linkage is difficult for the user. The exact effects of their settings are unknown. In particular, slip depends on tire and soil properties. Therefore, rear linkage adjustments are usually made once at the start of a work process and are not adjusted to the current situation.On inclines and declines, weight effects overlay a measured traction resistance force of the traction control and can lead to the working depth of an attachment being changed.

[0005] Incorrect settings of the rear power lift lead to increased fuel consumption, reduced area performance, increased wear and poorer work results.

[0006] Maximum slip is therefore traditionally set manually by the user based on their experience. Depending on experience and the situation, this setting is not always close to optimal.

[0007] In principle, various methods for supporting the user are known, but these still require further optimization. For example, WO 2016 / 078782 A1, EP 2 583 543 A1, and EP 3 305 053 A1 generally disclose methods for determining the operating parameters of an agricultural vehicle based on slip. In particular, there is a need for a way to optimize the setting of the maximum slip.

[0008] It is a challenge to improve the known state of the art.

[0009] The invention is based on the problem of designing and developing the known methods in such a way that an optimized adjustment of the rear power lift is achieved.

[0010] The above problem is solved by the features of the characterising part of claim 1.

[0011] The fundamental idea is that a driver assistance system of an agricultural machine, depending on at least one existing soil property and at least one existing tire property, can determine a slip that is optimized to improve the performance of a given control system, i.e., position control, draft control, and / or working depth control. Instead of a user setting a maximum slip, the driver assistance system controls the slip so that a predefined optimization goal is achieved. This optimization goal can, in particular, be maximum traction efficiency or a maximum traction coefficient. This allows even an inexperienced user to achieve a high level of efficiency in adjusting the slip by leaving this setting to the driver assistance system.

[0012] In detail, it is proposed that the driver assistance system determines, depending on at least one existing soil property and at least one existing tire property, a target slip for the slip control that is optimized with regard to the position control and / or traction control and / or working depth control and controls the rear power lift to the optimized target slip.

[0013] To detect at least one existing soil property, the agricultural vehicle according to claim 2 can have a sensor. Soil properties can be location-dependent, i.e., they can vary across the field, change over time, for example, during rain, and have a significant overall influence on optimal slip. Sensor detection can take some of these influences into account.

[0014] According to claim 3, additional soil properties can be entered by a user or stored in a database. For example, a soil type does not change, or at least not at a relevant rate, and is difficult to detect by sensors.

[0015] Furthermore, according to claim 4, the agricultural vehicle can have a sensor for detecting at least one existing tire property. Additionally or alternatively, the tire property can be entered by a user or stored in a database. Some tire properties can also be advantageously detected by sensors, while others cannot.

[0016] Claim 5 specifies machine parameters of the rear power lift preferably set by the driver assistance system.

[0017] According to claim 6, the driver assistance system determines the target slip preferably to achieve maximum traction efficiency or to achieve a maximum traction coefficient, or with regard to a combination thereof. Depending on user specifications or other specifications, higher efficiency is desired in some situations, and maximum speed or traction in others. These specifications can be taken into account in this way.

[0018] In certain circumstances, it may be desirable to deactivate the slip control. According to claim 7, the driver assistance system can then use traction control, position control, or mixed control based on the ground and tire properties.

[0019] Overall, in addition to the target slip, the driver assistance system can determine a setting for a mixed factor for a mixed control system comprising position control and traction control. Often, the user's goals are less technical than specifying a desired mixed factor, which serves merely as a means to an end. In particular, based on user specifications, the driver assistance system can take over the work of the control system and the specifications for the control system. This embodiment is the subject of claim 8.

[0020] Since not all necessary ground and tire properties are always available, according to claim 9, the driver assistance system can determine a map in a map routine that maps the interdependencies between ground, tires, and slip and serves as the basis for determining the target slip. This map routine can run across multiple work processes and improve incrementally, or it can run during each work process or as needed.

[0021] In a preferred embodiment according to claim 10, the agricultural implement can be provided with a sensor for determining an absolute working depth for working depth control. This makes it possible to directly control one of the most important machine parameters, namely the working depth, of the implement, using precise measurement data for this purpose and taking efficiency aspects into account overlaid with the slip control.

[0022] The machine parameters of the attachment are also relevant for a work process. Similar to the working depth control, these can be controlled or regulated depending on the target slip, or the target slip can be determined depending on the machine parameters. This also improves the coordination between slip and actual field cultivation. Various machine parameters of the combination have different influences on the slip and the work result. If the optimized target slip does not allow enough flexibility to adjust all machine parameters as desired, the slip control would partially lift the attachment. The proposed solution allows another machine parameter that influences the slip but, for example, has a lesser influence on the work result to be changed instead.

[0023] When the tractor-trailer combination travels up a slope, conventional systems often partially raise the implement, especially a plow, to compensate for the increased drive power requirement. According to claim 12, it is proposed to take the total weight of the tractor-trailer combination and the incline into account to counteract this effect. The target slip can be increased, in particular, to achieve a more consistent working depth on a slope, for example, at the expense of drive power efficiency.

[0024] According to a further teaching according to claim 13, which has independent significance, an agricultural team is claimed.

[0025] It is essential that the driver assistance system determines a target slip for the slip control that is optimized with regard to the position control and / or traction control, depending on at least one existing soil property and at least one existing tire property, and controls the rear power lift to the optimized target slip.

[0026] Reference may be made to all statements relating to the proposed procedure.

[0027] The invention will be explained in more detail below with reference to a drawing which merely represents an exemplary embodiment. Fig. 1 shows an agricultural team for use in the proposed method and Fig. 2 schematically shows the relationship between slip and traction efficiency.

[0028] In the illustrated and, in this respect, preferred embodiment, the agricultural work machine 1 is a tractor. It has a rear power lift 2 configured as a three-point linkage. An attachment 3 attached to the rear power lift 2 can, in particular, be a soil cultivation implement such as a plow 4, a cultivator, or a harrow. Together, the agricultural work machine 1 and the agricultural attachment 3 form an agricultural combination 5.

[0029] The exemplary embodiment shown in the figures and preferred in this respect relates to a method for controlling a rear power lift 2 of an agricultural working machine 1 in an agricultural combination 5, wherein the agricultural combination 5 has an agricultural working machine 1 and an agricultural attachment 3 and wherein the agricultural attachment 3 is connected to the agricultural working machine 1 via a rear power lift 2 of the agricultural working machine 1.

[0030] The agricultural work machine 1 has a driver assistance system 6 that controls machine parameters of the rear power lift 2. The driver assistance system 6 controls the machine parameters, in particular kinematics, of the rear power lift 2 by means of a position control and / or a draft control and / or a working depth control, over which a slip control is superimposed.

[0031] Position control and draft control have been known for a long time. With working depth control, the working depth 7 of the implement 3 is set to a predetermined value, and the draft and position of the rear power lift 2 are adjusted accordingly if necessary. This working depth 7 can be location-dependent, meaning it can vary across the field during a work process.

[0032] The driver assistance system 6 can be part of the agricultural work machine 1, but can also be arranged externally to the agricultural work machine 1, for example as a cloud control arrangement.

[0033] It is now essential that the driver assistance system 6, depending on at least one existing soil property and at least one existing tire property, determines a target slip P for the slip control that is optimized with regard to the position control and / or traction control and / or working depth control and controls the rear power lift 2 to the optimized target slip P.

[0034] Fig. 1 clarifies the two-part nature of the regulation. Fig. 1A schematic block diagram of the driver assistance system 6. The first block M contains a calculation rule, for example, an expert model or characteristic map model for determining the optimized target slip P. This is transferred to the second block R. The second block R contains the position control and / or traction control and / or working depth control, over which the slip control is superimposed. Data from a database, in particular the soil properties and / or tire properties and other data of the agricultural vehicle combination 5, flow into the first block M.

[0035] The settings of the driver assistance system 6 can generally be made in a dialogue-based manner with the involvement of the user 8.

[0036] The term "optimized target slip" does not necessarily refer to the optimal target slip P. It is sufficient that optimization is carried out with respect to some kind of optimal target slip P. The optimization goal can be specified by the user 8 or otherwise. This will be explained in more detail below. As already mentioned in the introduction, the optimal target slip P depends on the soil properties and the tire properties. It can differ significantly between wet and dry soil, for example. Optimization can preferably be carried out using an expert model. Various measurement series on the topic of "optimal slip" are known, which can be implemented in such an expert model. Here and preferably, the optimized target slip P is a maximum slip. If this is reached or exceeded, the attachment 3 is partially raised to reduce the slip again.It is therefore not the case that the target slip P is necessarily set permanently.

[0037] Fig. 2 shows a schematic representation of the relationship between a percentage slip S on the abscissa and a driving force efficiency T on the ordinate during field work. The various curves K relate to different soil properties. The maximum of the curves K, for typical soil properties, lies in the range of a percentage slip S of 10% to 20%. The respective maximum driving force efficiency O lies between approximately 50% and 80% and is marked with a circle, while the diamond indicates an optimal slip for a maximum driving force coefficient D. The graph is only schematic.

[0038] Furthermore, it is preferably provided here that the agricultural vehicle 5 has a sensor 9 for detecting at least one of the existing soil properties, preferably that the sensor 9 detects a slope of the soil and / or a surface property of the soil, in particular a crumbling of the soil and / or a leveling of the soil.

[0039] How Fig. 1represents, it can be provided that the sensor 9 is located in an area before soil cultivation by the attachment 3. In particular, the sensor 9 can be located on the agricultural work machine 1. The sensor 9 can basically be a sensor 9 based on electromagnetic waves or acoustic waves. The sensor 9 can be a radar sensor or a lidar sensor or an optical sensor or an ultrasonic sensor. Furthermore, the sensor 9 can also be an inclination sensor which detects an inclination of the agricultural work machine 1 and from this preferably deduces whether the machine is traveling uphill or downhill. The incline as a soil property is particularly relevant in the present case, since it can be detected with very little effort and at the same time it has a major influence on the control of the rear power lift 2.

[0040] It can be provided that at least one of the soil properties is entered by a user 8 and / or stored in a database DB. The at least one soil property can be stored in the database DB in a location-dependent manner. It is preferred that the at least one soil property in the database DB includes compaction.

[0041] Regardless of its origin, the ground property can be location-dependent. This is usually inherent in a sensor 9, but it is also preferred for a ground property that is input or originates from a database DB. The ground property can, for example, include lane data that allows conclusions to be drawn about compaction in the lanes. The database DB can generally be part of the driver assistance system 6, or the data can be transmitted to the driver assistance system 6.

[0042] The term "location-dependent" means that soil properties vary across a field and therefore still have a spatial resolution on the individual field.

[0043] Additionally or alternatively, it can be provided that the agricultural vehicle 5 has a sensor 9 for detecting at least one existing tire property, and / or that at least one of the at least one tire property is entered by the user 8 and / or stored in the database DB. In this respect, the statements regarding the soil properties apply accordingly.

[0044] It is preferably provided that the at least one tire property comprises a weight of the agricultural work machine 1, in particular an axle load and / or an axle ballasting, and / or a tire size and / or a rolling radius of the tire and / or a tire pressure.

[0045] All of the above properties can be used individually or in any combination. The tire properties can each affect one or more tires. Overall, therefore, slip depends on the ground, the weight on the tire, the tire materials, and so on. Therefore, these properties can be considered to determine the target slip P.

[0046] Within the framework of the respective regulations, it may now be the case that the driver assistance system 6 on the rear power lift 2 regulates as machine parameters a lifting gear position of the top link 10 and / or one or more of the lower links 11 and / or a lifting gear force of one or more of the lower links 11 and / or a length of the top link 10 and / or one or more of the lower links 11 and / or a lifting strut and / or a top link force 10. It should be noted that the driver assistance system 6 is defined broadly here. It may also have a rear force controller, which as such can be an independent module and which is Fig. 1 represented by the second block R.

[0047] Furthermore, it is preferably provided here that the driver assistance system 6 determines the target slip P in order to achieve a maximum traction efficiency or a maximum traction coefficient or with regard to an optimized combination of traction efficiency and traction coefficient.

[0048] The optimization with regard to the drive efficiency and the drive accessory is here and preferably dependent on a user specification. This user specification can be a target specification. The target specification can be a minimization of consumption or a maximization of the speed of the work process and / or a minimization of the process costs and / or a maximization of work quality. Preferably, the user 8 can set the weighting of the target specifications visually on the agricultural work machine 1.

[0049] It can also be provided that the driver assistance system 6, based on the at least one existing soil property and the at least one existing tire property, temporarily controls the rear power lift 2 using position control without slip control and / or traction control without slip control and / or a mixed control system comprising position control and traction control without slip control, and preferably determines an optimized mixed factor of the mixed control for this purpose. Additionally or alternatively, the driver assistance system 6 can determine the optimized mixed factor for periods in which the target slip P is not reached and the slip control therefore does not take effect.

[0050] This takes into account the fact that slip control is not always possible or sensible. Thus, the driver assistance system 6 can fall back on known control systems. In particular, it can be provided that the driver assistance system 6 detects a lack of information regarding the ground and tire properties and deduces from this that an optimized target slip P cannot be determined with sufficient certainty.

[0051] Furthermore, it is preferably provided here that the driver assistance system 6 determines an optimized setting of a mixing factor of a mixed control system comprising position control and traction control on the basis of the at least one existing ground property and the at least one existing tire property and / or the desired slip and controls the rear power lift 2 based thereon.

[0052] In addition to slip control, the position control or traction control, or in particular their combination, can also be optimized by the driver assistance system 6. This can be done to achieve a user specification. Thus, the user 8 can, for example, make the aforementioned target specifications or set a desired working depth 7, and the driver assistance system 6 takes over the control of the rear power lift 2. The driver assistance system 6 can then, by default, optimize the slip with regard to efficiency, provided there is still room for maneuver.

[0053] Preferably, the driver assistance system 6 determines the mixing factor and preferably the target slip P to achieve a specification, in particular a user specification. The specification can in particular be a specified working depth 7 or a specified driving speed or a specified tractive force. A preferred procedure is for the user 8 to specify a working depth 7, and the tractive force and preferably a driving speed of the tractor / trailer combination 5 are derived from the target slip P, since the agricultural work machine typically operates at or close to full load during soil cultivation.

[0054] It is also possible for the driver assistance system 6 to vary the settings of the rear power lift 2 in a map routine for given soil properties and tire properties in order to determine dependencies between the soil properties and tire properties and the slip, in particular in the form of a map, and then to determine the target slip P based thereon.

[0055] This makes it possible to determine the influences of unknown tire and soil properties, or unknown influences on slip. The map routine can be run across multiple work processes, thus leading to optimization step by step, or can be performed at the beginning of each work process, if necessary.

[0056] Characteristic maps are equations or combinations of equations and / or inequalities or otherwise depicted dependencies between settings of machine parameters, measured data, influencing factors and the like.

[0057] Furthermore, it is preferably provided here that the agricultural attachment 3 has a sensor 9 for determining an absolute working depth 7 for the working depth control.

[0058] The sensor measures an absolute working depth. The term "absolute" does not necessarily refer to a highly precise measurement, but rather a general measurement relative to the ground. It is conceivable that the measurement is taken relative to a component whose height relative to the ground is known, but preferably the absolute working depth is measured directly relative to the ground.

[0059] The sensor can be part of a sensor assembly. The sensor assembly can have at least one sensor mount, wherein the sensor is reversibly mounted at a mounting position on different attachments by means of the at least one sensor mount.

[0060] The sensor is mounted at the mounting position using the sensor mount in such a way that the installation is non-destructive and reversible. In particular, it is not performed during the manufacture of the attachment, but rather can be carried out on-site in the field using simple tools or even without any tools at all.

[0061] The sensor can therefore be used with various attachments and is therefore modular. One advantageous application of this modular sensor technology also relates to the measurement of the working depth on an attachment that does not have its own electronics. As will be shown below, the sensor arrangement can therefore be independent of the attachment. Alternatively, it can be provided that the sensor does not communicate with the attachment. However, it can equally well be provided that the sensor is integrated into the electronics of the attachment or communicates with it. Even with attachments with electronics, however, it can be provided that the sensor does not communicate directly with the attachment. It is preferred that the sensor arrangement can be used with attachments with and without electronics. Overall, it can even be provided that the determination of the working depth is completely independent of the agricultural attachment.

[0062] Here, and preferably, it is provided that the sensor mount can be mounted separately from the sensor on the various attachments. The sensor can then be reversibly mounted on the sensor mount. In principle, it can be provided that the sensor mount is a relatively inexpensive mass-produced component, while the sensor itself is relatively expensive. The proposed method enables the reuse of the expensive sensor.

[0063] For convenience, however, the sensor mount may remain attached to the attachment. This allows for a more stable and more complex installation of the sensor mount, while preferably the sensor itself is relatively simple to mount. This also allows for the reuse of the same mounting position when reattaching the sensor.

[0064] To determine the working height, a reference height can be stored that indicates the working height at a known distance between the sensor and the ground. The working height can then be determined from the difference.

[0065] Furthermore, it is preferably provided here that the driver assistance system 6 further controls or regulates machine parameters of the attachment 3 as a function of the target slip P and / or determines the target slip P as a function of the machine parameters, preferably that the driver assistance system 6 controls or regulates a cutting width and / or a working depth 7 of a plough 4 as a function of the target slip P.

[0066] It can also be provided that the driver assistance system 6 continues to determine the target slip P as a function of the total weight of the agricultural combination 5 and the inclination of the ground and / or the agricultural combination 5. For this purpose, the agricultural combination 5 can have an inclination sensor for determining the inclination of the agricultural combination 5. Alternatively, the inclination of the ground can be taken from a database DB. The combined weight of the agricultural work machine 1 and the agricultural implement 3 significantly determines the behavior of the combination 5 on a slope.

[0067] Preferably, the driver assistance system 6 determines the weight of the agricultural vehicle combination 5 from an actual slip, in particular by successively adjusting the target slip. If the driver assistance system 6 sets a target slip P on a slope, the attachment is raised to a specific working depth 7 by the downstream control system. Conclusions about the weight can be drawn from this. Additionally or alternatively, the driver assistance system 6 can use another actual variable, in particular an actual position and / or an actual tractive force and / or an actual working depth, to determine the weight. The weight does not have to be determined as such; it is sufficient to adjust the target slip P depending on a weight-dependent variable determined in this way or on the basis of a calculation rule that indirectly takes the weight into account. Preferably, the target slip is adjusted depending on the weight on a slope.

[0068] However, the weight can also be entered by the user.

[0069] Also proposed according to a further teaching which is of independent importance is an agricultural combination 5, wherein the agricultural combination 5 has an agricultural working machine 1 and an agricultural attachment 3, wherein the agricultural attachment 3 is connected to the agricultural working machine 1 via a rear power lift 2 of the agricultural working machine 1, wherein the agricultural working machine 1 has a driver assistance system 6 which regulates machine parameters of the rear power lift 2, wherein the driver assistance system 6 regulates the machine parameters of the rear power lift 2 by means of a position control and / or a traction control, on which a slip control is superimposed.

[0070] It is now essential that the driver assistance system 6, depending on at least one existing soil property and at least one existing tire property, determines a target slip P for the slip control that is optimized with regard to the position control and / or traction control and controls the rear power lift 2 to the optimized target slip P.

[0071] Reference may be made to all statements relating to the proposed procedure. List of reference symbols

[0072] 1agricultural machine 2rear power lift 3agricultural implement 4plough 5agricultural team 6driver assistance system 7working depth 8user 9sensor 10top link 11lower link PSoll slip Merster block Rsecond block DBdatabase Spercentage slip TTructure efficiency KKurve Omaximum traction efficiency Dmaximum traction coefficient

Claims

1. A method for regulating a rear power lift (2) of an agricultural working machine (1) in an agricultural combination (5), wherein the agricultural combination (5) has an agricultural working machine (1) and an agricultural attachment (3), wherein the agricultural attachment (3) is connected to the agricultural working machine (1) via a rear power lift (2) of the agricultural working machine (1), wherein the agricultural working machine (1) has a driver assistance system (6) which regulates machine parameters of the rear power lift (2), wherein the driver assistance system (6) regulates the machine parameters of the rear power lift (2) by means of a position regulation and / or a tractive force regulation and / or a working depth regulation, on which a slip regulation is superimposed, characterized in that the driver assistance system (6) determines, as a function of at least one existing ground property and at least one existing tyre property, a slip setpoint (P) for the slip regulation which is optimised with regard to the position regulation and / or tractive force regulation and / or working depth regulation and regulates the rear power lift (2) towards the optimised slip setpoint (P).

2. The method according to claim 1, characterized in that the agricultural combination (5) has a sensor (9) for detecting at least one of the existing ground properties, preferably in that the sensor (9) detects a gradient of the ground and / or a surface property of the ground, in particular crumbling of the ground and / or levelling of the ground.

3. The method according to claim 1 or claim 2, characterized in that at least one of the ground properties is input by a user (8) and / or is stored in a database (DB), preferably in that the at least one ground property is stored in the database (DB) in a location-dependent manner, more preferably in that the at least one ground property in the database (DB) comprises a compaction.

4. The method according to one of the preceding claims, characterized in that the agricultural combination (5) has a sensor (9) for detecting at least one existing tyre property, and / or in that at least one of the at least one tyre properties is input by the user (8) and / or is stored in the database (DB), preferably in that the at least one tyre property is a weight of the agricultural working machine (1), in particular an axle loading and / or an axle ballast, and / or a tyre size and / or a rolling radius of the tyre and / or a tyre pressure.

5. The method according to one of the preceding claims, characterized in that the driver assistance system (6) regulates, as the machine parameter, a lifting gear position of the upper link (10) and / or of one of the lower links (11) or of the lower links (11) and / or a lifting gear force of one of the lower links (11) or of the lower links (11) and / or a length of the upper link (10) and / or of one of the lower links (11) or of the lower links (11) and / or of a lifting strut and / or an upper link force (10) on the rear power lift (2).

6. The method according to one of the preceding claims, characterized in that the driver assistance system (6) determines the slip setpoint (P) in order to obtain a maximum motive force efficiency or a maximum motive force coefficient or in view of obtaining an optimised combination of motive force efficiency and motive force coefficient.

7. The method according to one of the preceding claims, characterized in that, on the basis of the at least one existing ground property and the at least one existing tyre property, the driver assistance system (6) temporarily regulates the rear power lift (2) by means of a position regulation without slip regulation and / or a tractive force regulation without slip regulation and / or a combined regulation of position regulation and tractive force regulation without slip regulation and preferably determines an optimised combined factor of the combined regulation therefor.

8. The method according to one of the preceding claims, characterized in that, on the basis of the at least one existing ground property and the at least one existing tyre property and / or the slip setpoint, the driver assistance system (6) determines, in an optimised manner, a setting of a combined factor of a combined regulation of position regulation and tractive force regulation and regulates the rear power lift (2) on the basis thereof, preferably in that the driver assistance system (6) determines the combined factor and preferably the slip setpoint (P) in order to obtain a specification, in particular a user specification, more preferably in that the specification is a specified working depth (7) or a specified driving speed or a specified tractive force.

9. The method according to one of the preceding claims, characterized in that, in a characteristic diagram routine, for given ground properties and tyre properties, the driver assistance system (6) varies settings of the rear power lift (2) in order to determine dependencies between the ground properties and tyre properties and the slip, in particular in the form of a characteristic diagram, and then to determine the slip setpoint (P) on the basis thereof.

10. The method according to one of the preceding claims, characterized in that the agricultural attachment (3) has a sensor (9) for determining an absolute working depth (7) for the working depth regulation.

11. The method according to one of the preceding claims, characterized in that the driver assistance system (6) furthermore controls or regulates machine parameters of the attachment (3) as a function of the slip setpoint (P) and / or determines the slip setpoint (P) as a function of the machine parameters, preferably in that the driver assistance system (6) controls or regulates a cutting width and / or a working depth (7) of a plough (4) as a function of the slip setpoint (P).

12. The method according to one of the preceding claims, characterized in that the driver assistance system (6) furthermore determines the slip setpoint (P) as a function of a total weight of the agricultural combination (5) and of an inclination of the ground and / or of the agricultural combination (5).

13. An agricultural combination, wherein the agricultural combination (5) has an agricultural working machine (1) and an agricultural attachment (3), wherein the agricultural attachment (3) is connected to the agricultural working machine (1) via a rear power lift (2) of the agricultural working machine (1), wherein the agricultural working machine (1) has a driver assistance system (6) which is configured to regulate machine parameters of the rear power lift (2), wherein the driver assistance system (6) is configured to regulate the machine parameters of the rear power lift (2) by means of a position regulation and / or a tractive force regulation, on which a slip regulation is superimposed, characterized in that the driver assistance system (6) is further configured to determine, as a function of at least one existing ground property and at least one existing tyre property, a slip setpoint (P) for the slip regulation which is optimised with regard to the position regulation and / or tractive force regulation and to regulate the rear power lift (2) towards the optimised slip setpoint (P).