Agricultural equipment and methods for steering agricultural equipment

Abstract

Agricultural implement (1) which can be towed by means of a tractor (2), wherein the agricultural implement (1) comprises a first axle (3) with wheels (5) and a second axle (4) with wheels (5) arranged behind the first axle (3), where the first axle (3) and the second axle (4) are steerable axles and wherein in a first driving state (FZ1) the first axle (3) and the second axle (4) have steering angles (16, 17) in the same direction and in a second driving state (FZ2) the first axle (3) and the second axle (4) have steering angles (16, 17) in opposite directions, wherein it is possible to change from the first driving state (FZ1) to the second driving state (FZ2) and from the second driving state (FZ2) to the first driving state (FZ1), characterized by the fact that a sensor unit (6) is provided, wherein a steering angle (16) of the first axle (3) and / or a steering angle (17) of the second axle (4) can be determined by means of the sensor unit (6) and its sensor data, wherein if a required steering angle (16) of the first axle (3) and / or a required steering angle (17) of the second axle (4) is greater than a maximum possible steering angle of the respective axle (3, 4), a change from the first driving state (FZ1) to the second driving state (FZ2) can be made.

Description

[0001] The invention relates to an agricultural implement according to the preamble of claim 1. The invention further relates to a method for steering an agricultural implement.

[0002] There are known devices, in particular trailers, from the prior art which have a steerable axle to facilitate cornering, whether off-road or on the road, since such devices are designed to be correspondingly large and long for efficient use.

[0003] To ensure that the axle or axles of the devices can follow the axles of a towing vehicle as closely as possible, in order to keep the area driven over as small as possible, steering systems are already known, such as those from EP 3 090 922 A1 or EP 1 081 020 A2.

[0004] DE 10 2018 215 615 A1 concerns, by way of general term, a forced steering system for an agricultural or forestry trailer which includes at least two forced-steered axles. Two different driving states can be identified.

[0005] However, if the turning radius due to the driving movement of the tractor is smaller than the maximum possible steering angle of the wheels and axles of the device, it can happen that the wheels are moved along a curve in a maximally steered position, thereby exerting forces on the wheels and axles and deforming the rim of the wheel or axles, so that damage to the wheel or axles or the entire steering system of the device can result.

[0006] It is therefore an object of the present invention to provide an agricultural device and a method for steering an agricultural device by means of which the disadvantages of the prior art can be overcome, so that on the one hand damage to the steering of the device can be prevented and on the other hand the best possible tracking of a path of the tractor is possible.

[0007] This problem is solved by an agricultural device with the features of claim 1 and by a method with the features of claim 12. Advantageous embodiments of the invention are found in the dependent claims.

[0008] The core idea of ​​the invention is to provide an agricultural implement, in particular a trailer, which can be towed by a tractor, wherein the agricultural implement comprises a first axle with wheels and a second axle with wheels arranged behind the first axle, wherein the first axle and the second axle are steerable axles and wherein in a first driving condition the first axle and the second axle have a steering angle in the same direction and in a second driving condition the first axle and the second axle have an opposite steering angle, wherein it is possible to switch from the first driving condition to the second driving condition and from the second driving condition to the first driving condition.

[0009] Examples of such agricultural equipment include a fertilizer spreader, a field sprayer, a storage container, or the like.

[0010] From a certain design, such agricultural equipment has at least two axles in order to comply with legal requirements, for example regarding the maximum axle load during road travel.

[0011] When driving across a field, it is advantageous for agricultural equipment to be moved in existing and designated tramlines in order to reduce the area of ​​the field driven over.

[0012] Preferably, the device and the tractor are connected to each other at a single attachment point by means of a towing device.

[0013] Furthermore, it is conceivable that the towing device is, for example, a drawbar. It is particularly preferred that the towing device of the agricultural implement is steerable, meaning that the towing device also includes a variable steering angle or turning angle. The towing device or drawbar can thus be understood as a third steerable axle.

[0014] The first and second axles are arranged one behind the other when viewed along the longitudinal axis of the agricultural implement.

[0015] The first axle and the second axle of the agricultural implement are each assigned at least one wheel, preferably two or more wheels, which are spaced apart from each other, preferably in a width dimension of the agricultural implement.

[0016] A steerable axle means that the steering angle or turning angle of the wheels of an axle can be changed.

[0017] According to the invention, a first driving state and a second driving state are provided, wherein in the first driving state the first axle and the second axle have a steering angle in the same direction and in the second driving state the first axle and the second axle have an opposite steering angle.

[0018] Preferably, but not required, the steering angle is specified with respect to a normal condition. The normal condition is particularly preferably a steering angle of 0° for each axle, which corresponds to straight-ahead travel of the device or the vehicle combination. The steering angles of the axles or wheels are specified with respect to the normal condition, resulting in positive and / or negative steering angles.

[0019] Same direction or equal steering angle means that the wheels of both axles are turned in the same direction, i.e., either to the left or to the right. In other words, the steering angles of the axles are either both positive or both negative.

[0020] Opposite steering angles mean that the wheels of one axle are turned in a different direction than the wheels of the other axle; for example, the wheels of the first axle turn right and the wheels of the second axle turn left. In other words, the steering angle of one axle is positive and the steering angle of the other axle is negative.

[0021] In the first driving condition, i.e., with the steering angles of the first and second axles aligned, the agricultural implement can maintain the most accurate tracking possible; this means that the wheels of the agricultural implement follow the wheels of the tractor as closely as possible. The area traversed by the implement, or rather by its wheels, can therefore be minimized.

[0022] In the second driving mode, the opposite design of the steering angles of the first and second axles allows for the smallest possible turning circle or curve radius of the implement. This is particularly advantageous when driving around tight curves. Although the area traversed by the agricultural implement is increased in the second driving mode, damage to the steering system can be avoided.

[0023] Furthermore, according to the invention, it is provided that a change between the first driving state and the second driving state is possible, i.e. from the first driving state to the second driving state and from the second driving state to the first driving state.

[0024] Preferably, a first actuator is assigned to the first axis and a second actuator to the second axis, wherein the actuators are each designed to be able to adjust the respective steering angle of the axes.

[0025] Preferably, a control and / or regulation unit is provided, which is designed to control the respective axis or the respective actuators.

[0026] It is intended that if a required steering angle of the first axle and / or a required steering angle of the second axle is greater than a maximum possible steering angle of the respective axle, it is possible to switch from the first driving state to the second driving state.

[0027] The control and / or regulation unit can perform a comparison of the required steering angles with the respective maximum possible steering angle.

[0028] The required steering angle should be adjusted to follow the tractor's track as precisely as possible. To avoid damage, a larger area is traversed, and the system switches to the second driving mode. By positioning the first and second axles in opposite directions, a smaller turning radius can be achieved, allowing the system to follow the tractor without damaging the agricultural implement.

[0029] A maximum possible steering angle of up to 35° is preferably possible, both to the left and to the right. This means that a wheel can steer up to 35° to the left as well as up to 35° to the right. A maximum possible steering angle of 30° is preferred, and 25° in one direction is even more preferred, although other values ​​are also conceivable. An angle of 10° is particularly preferred.

[0030] It is further preferred that the maximum possible steering angle can be predefined or is already predefined, and can be stored, for example, in a memory unit. The maximum possible steering angle can therefore differ from the technically feasible maximum steering angle. The memory unit and the control unit are preferably connected, at least via signals. The memory unit can preferably be designed as part of the control unit.

[0031] However, if, according to the preferred embodiment, a required steering angle of the first axle is greater than a maximum possible steering angle of the first axle and / or the steering angle of the second axle is greater than a maximum possible steering angle of the second axle, which is limited, for example, by the design or geometry of the agricultural implement, then the tractor can no longer be followed optimally and damage to the steering system may occur.

[0032] A sensor unit is provided, which is preferably assigned to and / or arranged on the agricultural implement, wherein a steering angle of the first axle and / or a steering angle of the second axle can be determined by means of the sensor unit and its acquired sensor data. Preferably, the sensor unit is connected to the control unit, at least via signal transmission.

[0033] According to a particularly preferred embodiment, the steering angle of one axis is determined, and the steering angle of the other axis is adjustable depending on the steering angle of the first axis. For example, the steering angle of the first axis is determined, and the steering angle of the second axis is set depending on the steering angle of the first axis.

[0034] The determination of the steering angle of an axle, for example the first axle or the second axle, is described in more detail below.

[0035] The movement of the agricultural implement can be detected by means of at least one sensor unit assigned to the implement, preferably a sensor unit functionally and / or spatially assigned to the implement, and the sensor data can be evaluated during the movement of the tractor and the implement to obtain control data for the steering of the first or second axle. Furthermore, the steering angle or turning angle of the axles or wheels of the axles and / or the drawbar of the implement can be calculated based on a path of the tractor calculated from the sensor data, in order to approximately follow the path of the tractor by the variable steering angle of the implement.

[0036] It is also conceivable that the sensor unit is assigned to the tractor unit.

[0037] The sensor unit assigned to the agricultural implement can preferably be arranged on the implement's frame. Based on the implement's movement, or its detected path or parts thereof, the tractor's movement can then be determined with sufficient accuracy. Given the implement's known position and orientation, the tractor's attachment point can be determined using the length of the towing device, preferably the drawbar. The tractor's position can thus be narrowed down.

[0038] By analyzing the temporal progression of individual positions and the changes in the implement's position, the tractor's trajectory can be determined with sufficient accuracy. Based on this calculated trajectory, the tractor's movement is also known, allowing the implement's steering angle, or the individual steering angles of the first or second axle, to be calculated using the acquired data. It is possible that the implement follows the tractor's path based on its movement data; that is, the implement's steering is based on its recorded movement. To determine the tractor's path, the current steering angle of the implement's first or second axle and / or drawbar should also be recorded, as this information is factored into the calculation of the steering angles.

[0039] According to a further preferred embodiment, it is provided that, starting from a determined steering angle of the first axis, the steering angle of the second axis is adjustable, or, starting from a determined steering angle of the second axis, the steering angle of the first axis is adjustable.

[0040] It is important to consider the current driving mode of the device. In the first driving mode, it is preferably intended that the steering angle of the second axis is set so that it essentially corresponds to the steering angle of the first axis, or vice versa. "Essentially" here can mean that a certain offset is conceivable, which is preferably in a range of up to 15°, more preferably up to 10° or up to 5°. It is further preferably conceivable that the offset of the other steering angle can be adjusted depending on the size of the steering angle of the first axis, for example, such that the larger the steering angle of the first axis, the greater the offset of the second axis.

[0041] In summary, the device is preferably characterized by the ability to determine the path of any point on the agricultural implement. If the attachment point is known at any given time, the path dictated by the tractor can be determined at any time or program cycle. The path to be tracked can be entered and stored on a local, two-dimensional or higher-dimensional map. The movement of the implement, i.e., its current position, can be detected by means of at least one sensor unit functionally and / or spatially assigned to the device, preferably a sensor unit exclusively assigned to the device.

[0042] The current position of the agricultural implement and its hitch point can preferably be entered on the local, two-dimensional or higher-dimensional map. Based on the implement's current position and hitch point, the steering angle of the first or second axle and / or the drawbar can be calculated, and the other axle can be adjusted accordingly. This allows the implement to follow the path dictated by the towing vehicle and / or, in case of deviations, to be guided back to that path.

[0043] If all positions of the tractor and the attached agricultural implement are known, path deviations caused by sluggish steering response of the implement can be calculated. These path deviations can be minimized by improved steering angle control or by an additional lead angle that steers towards the desired path.

[0044] A preferred embodiment of the invention provides that the movement of the agricultural device, in particular of the first axis and / or the second axis, can be detected by means of at least one gyroscope and / or an accelerometer.

[0045] Preferably, the at least one gyroscope and / or the acceleration sensors are assigned to the device and / or the tractor. These can be fixed and / or detachably arranged on the agricultural device and / or the tractor. The at least one gyroscope can preferably be positioned on a frame.

[0046] The advantage is that changes in direction of the device and / or the tractor can be measured using the gyroscope, so that, conversely, the path of the tractor can be determined based on the distance traveled measured by the displacement system and / or speed sensor. Possible changes in direction of the device can occur when cornering and / or when the tractor is turning.

[0047] Using at least one gyroscope, the rotational speed of the device around its vertical axis can be measured during cornering. The translational motion, on the other hand, can be measured at at least one wheel on the first or second axis of the device. In principle, however, the rotational speed of the device around its vertical axis can be measured at any time step using the gyroscope, especially during straight-line travel.

[0048] Other specific sensors can be inertial sensors and / or sensors for determining velocity and / or acceleration. Furthermore, any other type of detection can be used that describes the movement of the towed device, in particular the first or second axis, in two-dimensional or higher-dimensional space.

[0049] The acquired sensor data can then be evaluated by a control unit for steering the first or second axle of the device and / or the drawbar, so that the steering angle of the wheels of the first or second axle of the device and / or the drawbar can subsequently be calculated to track the path of the tractor. Based on this result, the actuator can generate a corresponding actuating torque to deflect the first or second axle or the wheels of the respective axle of the device and / or the drawbar.

[0050] It may also be provided that the movement of the device and / or the tractor is recorded by means of at least one distance measuring system and / or speed sensor.

[0051] The at least one displacement measuring system and / or speed sensor can be assigned to the device, preferably exclusively to the device, which can be fixed and / or detachable. Furthermore, any other type of detection can be used that describes the movement of the towed device and / or the towing vehicle in two-dimensional or higher-dimensional space.

[0052] It may also be provided that the position and / or movement of the device and / or the tractor are recorded by a positioning system that is functionally and / or spatially assigned to the device and / or the tractor. It is particularly preferred that the positioning system is exclusively assigned to the device.

[0053] The position of the implement and / or the tractor can be determined, for example, using GPS, so that the current position of the implement and / or the tractor is transmitted, preferably continuously. It is also advantageous that, when determining the position, for example using GPS, inferences can be drawn about the speed of the implement and / or the tractor. The measured data can be evaluated by the control unit to calculate the steering angles of the first axle or the second axle and / or the drawbar of the implement. To determine the path of the tractor, the current steering angle of the first axle or the second axle and / or the drawbar of the implement can also be recorded, which is then factored into the calculation of the steering angles. Such positioning systems can be fixed and / or detachable.

[0054] An advantageous embodiment provides that the sensor data of the sensor unit are updated at regular intervals during a driving movement of the tractor.

[0055] As the tractor unit moves, the device also moves continuously. To enable the approximate tracking of the tractor unit's path, it is necessary to regularly query the device's position. Changes in the device's position can be advantageously detected and evaluated directly, allowing for the calculation of the steering angles of the first or second axle and / or the drawbar. The intervals for updating the sensor data typically correspond to a defined time interval. It is also advantageous that the system's inertia with respect to the deflection of the first axle, the second axle, and / or the trailer's drawbar can be taken into account.

[0056] According to a further embodiment, a steering movement of the device can be carried out in real time when the movement of the device is detected by the sensor unit.

[0057] According to a preferred embodiment, it is possible to capture the movement and position of the device in real time in order to initiate a steering movement of the first or second axis of the device. The real-time data can be used to draw conclusions about the current position and movement of the device and to calculate the steering angle of the first or second axis and / or the drawbar of the device, for example by the control unit.

[0058] A further embodiment provides that the steering of the first axle or the second axle and / or the drawbar of the device is carried out on the basis of the calculated movement data of the device.

[0059] The advantage is that, based on the calculated steering angles and the variable steering angle of the first or second axle of the device, and derived from the previously recorded movement data, the steering of the first or second axle and / or the drawbar of the device is controlled. This allows the first or second axle and / or the drawbar of the device to be deflected by an actuator-generated control element in such a way that they follow the path of the towing vehicle.

[0060] It may also be provided that the steering movement of the first axle and / or the second axle of the device is carried out in the opposite direction to the turning movement of the towing vehicle.

[0061] Due to the trailer's opposing deflection, the implement's path follows the same radius as the towing vehicle's path; that is, the implement, with its first or second axle wheels, travels the same curve radii or path as the rear wheels of the towing vehicle. Otherwise, the implement, due to its being pulled, would travel a smaller curve radius and cut across the path dictated by the towing vehicle.

[0062] The invention further comprises at least one actuator by means of which a steering movement of the first axle or the second axle and / or the drawbar can be effected, wherein preferably a first actuator by means of which a steering movement of the first axle can be effected, a second actuator by means of which a steering movement of the second axle can be effected, and more preferably a third actuator by means of which a steering movement of the drawbar can be effected, wherein preferably the control and / or regulation unit is connected to the at least one sensor unit and at least one of the actuators, wherein preferably the control and / or regulation unit is designed such that it can control the at least one actuator for a defined movement of the first axle or the second axle and / or a drawbar, taking into account the movement of the device detected by the at least one sensor unit.Preferably, it may be provided that each wheel of the trailer coupled to the steerable axle can be moved at least approximately in one lane of the tractor unit.

[0063] The at least one actuator can comprise at least one cylinder, which can be hydraulically and / or electrically controlled. As a result, the actuator can generate a torque on the first axle or the second axle and / or the steerable drawbar to achieve the previously calculated steering angle, depending on the tractor's turning maneuver, and a rotational movement of the first axle or the second axle of the implement.

[0064] If the positions, preferably all positions, of the tractor and the implement are known, path deviations caused by sluggish steering response of the implement can be calculated. These path deviations can be minimized by improved steering angle control or by an additional lead angle of the first or second axle, which steers towards the desired path.

[0065] A further advantageous embodiment of the invention provides that the at least sensor unit can comprise motion and / or speed sensors and / or a gyroscope.

[0066] To detect the device's movement by the tractor, the device is equipped with various types of sensors, such as motion and / or speed sensors. Likewise, any other type of detection that describes the device's movement in a two-dimensional or higher-dimensional space can be used. To determine the tractor's path with sufficient accuracy, it is also necessary to additionally detect the current steering angle of the first or second axle and / or the steerable drawbar. Based on the device's acquired movement data, it is possible to achieve at least an approximate tracking of the tractor's path with respect to the first or second axle by preferably using at least one actuator to control the deflection of the respective axle and / or drawbar.Such sensor units can be permanently attached to the device and / or be removable.

[0067] It is also possible for the sensor unit to be configured as a position determination system, either alternatively or cumulatively. Likewise, it is possible for the sensor unit to be located on the tractor unit.

[0068] Furthermore, it is advantageous to detect the movement of the device using position and orientation determination methods and subsequently to steer the first or second axle and / or a drawbar of the device. GPS, for example, can be used as a position determination system so that the respective position and speed of the device can be recorded. Such systems can be permanently and / or detachably mounted on the device.

[0069] According to the above description, it is therefore possible to determine the path of the first axle or the second axle, and if applicable the drawbar, in such a way that it is possible to follow the tractor, in particular the rear wheels of the tractor, as precisely as possible.

[0070] Preferably, only one path of one of the axes is selected from the first and second axes. Preferably, only the steering angle of one axis is determined using sensor data, and the steering angle of the other axis is set depending on the steering angle of the selected axis.

[0071] According to a particularly preferred embodiment, the change between the first driving state and the second driving state is performed automatically. If it is detected, for example by the control unit, that the required steering angle of the first axle and / or the second axle is greater than a maximum possible steering angle of the respective axle, a corresponding signal is sent by the control unit to the first actuator and / or the second actuator and / or the third actuator in order to adjust the steering angles of the axles in opposite directions.

[0072] According to a further preferred embodiment, it is provided that if the agricultural machine is in the second driving state and the required steering angle of the axles is smaller than the maximum possible steering angle of the axles, it is possible to switch from the second driving state to the first driving state.

[0073] According to a further preferred embodiment, the control unit is designed and configured to perform a change between the first driving state and the second driving state. For this purpose, the corresponding actuators can be controlled by the control unit, depending on which driving state has been detected.

[0074] Particularly preferably, the sensor unit may include a first angle sensor for detecting the steering angle of the first axis and / or the steering angle of the second axis. Alternatively or cumulatively, it is conceivable that a displacement measurement and / or a force measurement is carried out in actuators, preferably steering cylinders, wherein the actuators are assigned to the respective axis.

[0075] It is further preferred that at least one steering cylinder is assigned to the first axle and at least one steering cylinder to the second axle, wherein the first steering cylinder is intended to adjust the steering angle of the first axle, and wherein the second steering cylinder is intended to adjust the steering angle of the second axle. The first steering cylinder can correspond to the first actuator and the second steering cylinder to the second actuator. It is conceivable that the first axle and / or the second axle each have two steering cylinders, one for each wheel of the axle, so that the wheels can be controlled separately.

[0076] According to a further preferred embodiment, a third driving mode can be set, and in this third driving mode, one axle selected from the first and second axles has a fixed steering angle, while the other axle has a variable steering angle. Preferably, switching between the driving modes is possible.

[0077] This can correspond in particular to a driving condition on a road, so that controlling both axles simultaneously is not necessary, since minimizing the area driven over or preventing possible damage is not required.

[0078] The underlying problem is also solved by a method for steering an agricultural implement which is pulled by a tractor, wherein the agricultural implement comprises a first axle with wheels and a second axle with wheels arranged behind the first axle, wherein the first axle and the second axle are steerable axles, wherein the method comprises the following steps: a) Determining a steering angle of the first axis or determining a steering angle of the second axis; b) Comparing the determined steering angle of the first axle with a maximum possible steering angle of the first axle or comparing the determined steering angle of the second axle with a maximum possible steering angle of the second axle; c) Adjusting the steering angle of the second axle based on the determined steering angle of the first axle, or adjusting the steering angle of the first axle based on the determined steering angle of the second axle, wherein, if the determined steering angle of the first axle and the determined steering angle of the second axle are smaller than the corresponding maximum possible steering angle, setting a first driving condition in which the steering angles of the axles are in the same direction; and if at least one steering angle of the axles is greater than or equal to the corresponding maximum possible steering angle of the axle, setting a second driving condition in which the steering angles of the axles are in opposite directions.

[0079] Specifically, using the first axis as an example, this means: a) Determining a steering angle of the first axle; b) Comparing the determined steering angle of the first axle with a maximum possible steering angle of the first axle; c) Adjusting the steering angle of the second axle based on the determined steering angle of the first axle, or adjusting the steering angle of the first axle based on the determined steering angle of the second axle, whereby if the determined steering angle of the first axle and the determined steering angle of the second axle are smaller than the corresponding maximum possible steering angle, setting a first driving condition in which the steering angles of the axles are in the same direction; and if at least one steering angle of the axles is greater than or equal to the corresponding maximum possible steering angle of the axle, setting a second driving condition in which the steering angles of the axles are in opposite directions.

[0080] Further advantageous embodiments are described in the dependent claims.

[0081] The described characteristics regarding the device and the method can be exchanged in a corresponding manner and can be applied to both the device and the method in corresponding notation.

[0082] Further objectives, advantages, and suitability of the present invention can be found in the following description in conjunction with the drawings. The drawings show: Fig. 1 agricultural piece of equipment in accordance with the state of the art; Fig. 2. State-of-the-art methods; Fig. 3A agricultural equipment according to a preferred embodiment in a first driving condition; Fig. 3B agricultural equipment according to the embodiment of the Fig. 3A in a second driving state; Fig. 3C agricultural equipment according to a further embodiment; Fig. 4 methods for controlling the device.

[0083] In the figures, identical components are to be understood as having the corresponding reference numerals. For clarity, some components may not be marked with a reference numeral in some figures, but are identified elsewhere. The illustrated embodiments merely represent examples of how the inventive method or device may be configured and do not constitute an exhaustive limitation.

[0084] In the Fig. 1 and in the Fig. Figure 2 shows the known state of the art for adjusting the steering angle of a single axle 3, 4 of an agricultural implement 1, which is attached to a tractor 2 via a hitch point 11. The agricultural implement 1 and the tractor 2 form a tractor unit 100.

[0085] Fig. Figure 1 shows a tractor-implement combination 100 with a tractor 2 and an agricultural implement 1, which has a steerable axle 3, 4, pulled by the tractor 2 in a left-hand turn. The tractor 2 and the implement 1 are connected to each other at a hitch point 11 by means of a drawbar 12, in particular a drawbar. At least one sensor unit 6 is spatially and / or functionally assigned to the implement 1, which detects the movement of the implement 1. The at least one sensor unit 6 is preferably attached to the frame of the implement 1 and is designed as a gyroscope. The gyroscope detects the rotational speed of the implement 1 about a vertical axis at each time step, where the vertical axis corresponds to the z-axis. The translational speed is preferably measured at at least one wheel 5 of the implement 1.

[0086] Furthermore, the train assembly 100 comprises at least one actuator 8, 9 (not shown here), by means of which a steering movement of the steerable axle 3, 4 can be effected, and a control and / or regulation unit 7, which is in at least signal-technical communication with the at least one sensor unit 6 and the at least one actuator 8, 9. The control and / or regulation unit 7 is designed such that, based on the movement of the device 1 detected by the sensor unit 6, it can control the at least one actuator 8, 9 for a defined movement of the at least one steerable axle 3, 4. For this purpose, a steering angle 13 of the corresponding axle 3, 4 with at least two wheels 5 of the device 1 is calculated based on the sensor data in order to achieve at least an approximate tracking of a path 14 of the tractor 2, in particular the tracking of the path 14 by the rear wheels 15 of the tractor 2.

[0087] An actuator 8, 9 generates a steering torque, causing at least one steerable axle 3, 4 to turn at the calculated steering angle 13. The steering movement, based on the calculated motion data of the device 1, is opposite to the turning motion or the path 14 of the tractor 2, so that at least two wheels 5 of axle 3, 4 follow the path 14 of the tractor 2. Due to the regular updates of the sensor data from the sensor unit 6 during the tractor 2's movement, it is possible to continuously determine the path 14 of the tractor 2, the path to be followed, and the path and position of the device 1, and to continuously correct and / or adjust the steering angle 13 accordingly.

[0088] Fig. Figure 2 illustrates individual steps for implementing the method for steering a device 1 towed by a tractor 2, the device 1 having a steerable axle 3, 4, wherein the tractor 1 and the device 1 are connected to each other at a hitch point 11 by means of a drawbar 12. The movement of the device 1 towed by the tractor 2 is detected by at least one sensor unit 6, which is functionally and / or spatially assigned to the device 1.

[0089] The at least one sensor unit 6 is preferably a gyroscope to detect the rotational speed of the device 1 during changes of direction. The sensor data is then evaluated during the journey of the tractor 2 and the device 1 to obtain control data. This control data serves as the basis for steering the axles 3, 4 with wheels 5 of the device 1 and for determining the path of the tractor 2. The steering angle 13 of the axles 3, 4 of the device 1 is then calculated using the acquired control data to approximately track the path 14 of the tractor 2. To continuously adapt the steering movement of the device 1 to its position, movement, and speed, the sensor data is updated at regular intervals during travel, so that the movement of the device 1 is re-detected.

[0090] Based on the current position of device 1 and its attachment point 11, the steering angle of axle 3, 4 with the wheels 5 of device 1 and / or the drawbar 12 can be calculated. This allows device 1 to follow the path 14 specified by the tractor 2 and / or to return to this path in case of deviations.

[0091] In the Fig. Figure 3 shows the agricultural implement 1 according to a preferred embodiment in a first driving state FZ1. The implement 1 comprises a first steerable axle 3 and a second steerable axle 4, which are arranged one behind the other in one direction of extension of the implement 1. Wheels 5 are assigned to axles 3 and 4. The implement 1 is connected to the tractor 2 by means of a hitch point 11 and follows the tractor 2 accordingly. In the first driving state FZ1, axles 3 and 4 are steered in the same direction, in this example to the left.

[0092] The determination of the steering angle of the first axle 3 or the second axle 4 is in accordance with the state of the art, which is described in the Fig. As shown in 1, it has been carried out.

[0093] According to the invention, the steering angle of the second axis 3, 4 is also adjusted, preferably depending on the determined steering angle of the other axis 3, 4. This means, for example, that when the steering angle 16 of the first axis 3 is adjusted, the steering angle 17 of the second axis 4 is also adjusted. The same applies when the steering angle 17 of the second axis 4 is adjusted: the steering angle 16 of the first axis 3 is also adjusted.

[0094] According to the Fig. 3A is the steering angle 16 of the first axle 3 such that the wheels 5 of the first axle 3 follow the rear wheels or the path 18 of the rear wheels 15. Due to the geometry, in particular because the second axle 4 is arranged behind the first axle 3, the wheels 5 of the second axle 4 cannot follow the path 18 of the rear wheels 15 exactly, but describe a path 19 of the second axle 4 which is as close as possible to the path 19 of the rear wheels 15 in order to minimize the area 20 traveled by the wheels 15.

[0095] The steering angle 17 of the second axis 4 is preferably adjustable depending on the steering angle 16 of the first axis 3. It is conceivable that the steering angles 16 and 17 have the same angular value, although preferably, due to the arrangement of axes 3 and 4 relative to each other, a different angular value for axes 3 and 4 appears advantageous. It is also possible that the steering angle 17 of the second axis 4 is offset from the steering angle 16 of the first axis 3, i.e., with an additional angular value relative to the steering angle 16.

[0096] The setting of the steering angles 16, 17 or the control of the axes 3, 4 is carried out by means of the control and / or regulation unit 7, based on the sensor data of the sensor unit 6.

[0097] The control and / or regulation unit 7 preferably comprises a storage unit 10. Preferably, a maximum possible steering angle of each axis 3, 4 is stored in the storage unit 10 and can be recalled for comparison with the required steering angle 16, 17.

[0098] Similarly, for the first axle 3 and the second axle 4, the control unit 7 compares the required steering angle with the maximum possible steering angle of each axle 3, 4, and the respective driving state FZ1, FZ2 is set accordingly. The second driving state FZ2 is exemplified in the Fig. 3B is shown.

[0099] The surface 20 traversed is the surface which is traversed by the wheels 5, 15 and includes the tracks 18, 19 and is at least partially circular in shape when driving around a curve, with a ring thickness 21.

[0100] In the Fig. 3B is the embodiment according to the Fig. 3A is shown during a tighter turn and accordingly in the second driving condition FZ2, meaning that the steering angles 16, 17 are opposite to each other, i.e., one axis 3, 4 is deflected or rotated in a different direction than the other axis 3, 4. In the present case according to the Fig. 3B is the first axle 3 with wheels 5 oriented to the left and the second axle 4 with wheels 5 oriented to the right. This means that the steering angle 16, 17 of one axle 3, 4 is positive and the steering angle 16, 17 of the other axle 3, 4 is negative.

[0101] It is conceivable that a normal state is driving straight ahead. The steering angles 16, 17 in the normal state are therefore 0°. Steering angles 16, 17 deviating from the normal state are specified relative to this normal state.

[0102] As can be further seen, due to the fact that the agricultural machine 1 is in the second driving state FZ2, the area 20 driven over changes in order to be able to master the curve with as little damage as possible.

[0103] In the Fig. Figure 3C further shows a first actuator 8 and a second actuator 9, wherein the first actuator 8 is configured to adjust the steering angle 16 of the first axle 3, and wherein the second actuator 9 is configured to adjust the steering angle 17 of the second axle 4. Each actuator 8, 9 can include at least one steering cylinder, which can be hydraulically and / or electrically controlled. As a result, each actuator 8, 9 can generate an actuating torque for the wheels 5 of the steerable axles 3, 4 and / or the steerable drawbar 12 in order to effect the previously calculated steering angle depending on the turning maneuver of the tractor and a rotational movement of the wheels or axles 3, 4.

[0104] According to the Fig. Figure 4 shows a further method according to the invention, comprising the following process steps: a) Determining a steering angle of the first axis or determining a steering angle of the second axis; b) Comparing the determined steering angle of the first axle with a maximum possible steering angle of the first axle or comparing the determined steering angle of the second axle with a maximum possible steering angle of the second axle; c) Adjusting the steering angle of the second axle based on the determined steering angle of the first axle, or adjusting the steering angle of the first axle based on the determined steering angle of the second axle, wherein, if the determined steering angle of the first axle or the determined steering angle of the second axle is smaller than the corresponding maximum possible steering angle, setting a first driving condition in which the steering angles of the axles are in the same direction; and if at least one steering angle of the axles is greater than or equal to the corresponding maximum possible steering angle of the axle, setting a second driving condition in which the steering angles of the axles are in opposite directions.

[0105] The determined steering angle preferably corresponds to the required steering angle, so these formulations are synonymous.

[0106] The steering angle of an axis 3, 4 is preferably determined as described below. Fig.2 as described.

[0107] All features disclosed in the application documents are claimed to be essential to the invention, provided that they are novel individually or in combination compared to the prior art. Reference symbol list 1 Agricultural implement 2 tractor 3 first axis 4 second axis 5 wheels 6 sensor unit 7 Control and / or regulating unit 8 first actuator 9 second actor 10 storage units 11 Attachment point 12 Towing device, drawbar 13 Steering angle, steering angle 14 lane 15 rear wheel 16 Steering angle first axle 17 Steering angle second axle 18 Track of a rear wheel 19 Path of the second axis 20 areas driven over 21 Ring thickness 100 train sets FZ1 first driving condition FZ2 second driving mode FZ3 third driving mode

Claims

[1] Agricultural implement (1) which can be towed by means of a tractor (2), wherein the agricultural implement (1) comprises a first axle (3) with wheels (5) and a second axle (4) with wheels (5) arranged behind the first axle (3), where the first axle (3) and the second axle (4) are steerable axles and wherein in a first driving state (FZ1) the first axle (3) and the second axle (4) have steering angles (16, 17) in the same direction and in a second driving state (FZ2) the first axle (3) and the second axle (4) have steering angles (16, 17) in opposite directions, wherein it is possible to change from the first driving state (FZ1) to the second driving state (FZ2) and from the second driving state (FZ2) to the first driving state (FZ1), characterized by , that a sensor unit (6) is provided, wherein a steering angle (16) of the first axle (3) and / or a steering angle (17) of the second axle (4) can be determined by means of the sensor unit (6) and its sensor data, wherein if a required steering angle (16) of the first axle (3) and / or a required steering angle (17) of the second axle (4) is greater than a maximum possible steering angle of the respective axle (3, 4), a change from the first driving state (FZ1) to the second driving state (FZ2) can be made. [2] Agricultural implement (1) according to claim 1, characterized by , that the sensor unit (6) is assigned to and / or arranged on the agricultural device (1), [3] Agricultural implement (1) according to claim 2, characterized by, that starting from a determined steering angle (16) of the first axis (3) the steering angle (17) of the second axis (4) is adjustable, or starting from a determined steering angle (17) of the second axis (4) the steering angle (16) of the first axis (3) is adjustable. [4] Agricultural implement (1) according to any one of claims 1 to 3, characterized by , that the change between the first driving state (FZ1) and the second driving state (FZ2) can be carried out automatically. [5] Agricultural implement (1) according to any one of claims 1 to 4, characterized by , that if the agricultural implement (1) is in the second driving state (FZ2) and the required steering angle (16, 17) of the axles (3, 4) is each smaller than the maximum possible steering angle of the axles (3, 4), it is possible to switch from the second driving state (FZ2) to the first driving state (FZ1). [6] Agricultural implement (1) according to any one of claims 1 to 5, characterized by, that the sensor unit (6) comprises a first angle sensor for detecting the steering angle (16) of the first axis (3) and / or the steering angle (17) of the second axis (4). [7] Agricultural implement (1) according to any one of claims 1 to 6, characterized by , that the first axis (3) is assigned a first actuator (8) with at least one first steering cylinder and the second axis (4) is assigned a second actuator (9) with at least one second steering cylinder, wherein the first steering cylinder is intended to adjust the steering angle (16) of the first axis (3), and wherein the second steering cylinder is intended to adjust the steering angle (17) of the second axis (4). [8] Agricultural implement (1) according to any one of claims 1 to 7, characterized by , that the maximum possible steering angle can be stored in a storage unit (10). [9] Agricultural implement (1) according to any one of claims 1 to 8, characterized by, that a control and regulation unit (7) is provided which is designed and intended to perform a change between the first driving state (FZ1) and the second driving state (FZ2). [10] Agricultural implement (1) according to any one of claims 1 to 9, characterized by , that in a third driving condition (FZ3) one axle (3, 4) selected from the first axle (3) and the second axle (4) is unchangeable in its steering angle (16, 17) and the other axle (3, 4) is changeable in its steering angle (16, 17). [11] Method for steering an agricultural implement (1) which is pulled by a tractor (2), wherein the agricultural implement (1) comprises a first axle (3) with wheels (5) and a second axle (4) with wheels (5) arranged behind the first axle (3), wherein the first axle (3) and the second axle (4) are steerable axles, wherein the method comprises the following steps: a) Determining a steering angle (16) of the first axis (3) or determining a steering angle (17) of the second axis (4); b) Comparing the determined steering angle (16) of the first axis (3) with a maximum possible steering angle of the first axis (3) or comparing the determined steering angle (16) of the second axis (4) with a maximum possible steering angle of the second axis (4); c) Adjusting the steering angle (17) of the second axle (4) based on the determined steering angle (16) of the first axle (3), or adjusting the steering angle (16) of the first axle (3) based on the determined steering angle (17) of the second axle (4), wherein, if the determined steering angle (16) of the first axle (3) and the determined steering angle (17) of the second axle (4) are smaller than the corresponding maximum possible steering angle, adjusting the first driving condition (FZ1) in which the steering angles (16, 17) of the axles (3, 4) are in the same direction; and if at least one steering angle (16, 17) of the axles (3, 4) is greater than or equal to the corresponding maximum possible steering angle of the axle (3, 4), adjusting a second driving condition (FZ2) in which the steering angles (16, 17) of the axles (3, 4) are opposite directions.

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