SYSTEM AND METHOD FOR THE STEERING CONTROL OF A TRAINED SIDE-DRAINER

Description

[0001] The invention relates to a system and a method for steering control of a towed side rake and a correspondingly equipped side rake.

[0002] A trailed twin-rotor side-delivery rake is known, for example, from DE 102 05 499 A1. According to this patent, it comprises a front rotor unit with a drawbar and a hitch articulated to it and connected to a tractor, a rear rotor unit, and a longitudinal beam pivotally connected to the front and rear rotor units. When the rear rotor unit is offset to the left relative to the front rotor unit (viewed in the direction of travel) during operation, a swath is transferred from the front rotor unit to the rear rotor unit and deposited to the side. The lateral offset of the rear rotor unit is adjusted with a hydraulic steering cylinder and can be corrected by an additional steering cylinder when turning left, in order to transfer the swath as completely as possible from the front to the rear rotor unit.This correction is set by a control device located in the area of ​​the first gyroscope unit, which, for example, moves a control pin and a switching cam relative to each other depending on a longitudinal beam articulated to it between this unit and the longitudinal beam connected to it.

[0003] However, a disadvantage is that such a control mechanism is comparatively complex and difficult to position in the area of ​​the first rotor unit. Therefore, the design of the first rotor unit and the associated longitudinal beam may need to be fundamentally modified, which, for example, makes retrofitting twin-rotor side-delivery rakes with such a correction function difficult or even impossible.

[0004] An alternative control system for steering cylinders using hydraulic master cylinders requires numerous hydraulic components such as accumulators, valves, and the like. Mechanical components are also necessary, for example, to limit the stroke for creating side swaths or individual swaths, or for transport operations. All of this results in considerable equipment complexity and requires suitable installation space for the hydraulic and mechanical components.

[0005] There is therefore a need for improved systems and procedures for steering control of trailed side-delivery rakes, especially those with two rotor units.

[0006] The problem is solved by a system and a method according to the independent claims and by a correspondingly equipped side-delivery rake. Preferred embodiments are specified, among others, in the dependent claims.

[0007] The system is used for steering a trailed side-delivery rake, in particular a twin-rotor side-delivery rake, with a front and a rear rotor unit articulated by a longitudinal beam, and with a drawbar attached to the front rotor unit. The system comprises: a first sensor for measuring the steering angle formed between the longitudinal beam and the chassis of the rear rotor unit; a second sensor for measuring the caster angle formed between the longitudinal beam and the drawbar; a hydraulic steering cylinder for adjusting the steering angle; and an electronic control unit for regulating the hydraulic supply to the steering cylinder. The control unit is designed to regulate the hydraulic supply such that, in a selectable first steering mode for generating a side swath, the actual steering angle continuously approaches a first target value dependent on the measured caster angle.

[0008] The steering angle can thus be continuously adjusted and, if necessary, corrected during operation using electronic control to optimize the track of the rear rotor unit relative to the front rotor unit, particularly for optimal swath transfer from the front to the rear rotor unit. Compared to hydraulic and / or mechanical control of the steering angle, this system saves on equipment costs. Furthermore, electronic control allows for more flexible track adjustments for different driving situations.

[0009] The first sensor is preferably a position sensor that measures the angular position of the longitudinal member relative to the chassis of the rear gyro unit, for example in the form of a rotary encoder, or the retraction / extension position of the steering cylinder. The same applies to the second sensor, which measures the angular position relative to the chassis of the front gyro unit or the retraction / extension position of a further steering cylinder associated there. This is based on the fact that different length positions (retraction / extension positions) of the steering cylinders are each fixedly assigned known angular positions of the longitudinal member.

[0010] Preferably, the first steering mode is implemented in the control unit in such a way that the track of the rear gyroscope unit is automatically corrected towards the outside of the curve depending on the measured caster angle when it is offset to the left relative to the front gyroscope unit and when cornering to the left.

[0011] This enables overlap control, which automatically reduces the pivot angle formed, for example, between the direction of travel of the rear rotor unit and the longitudinal axis of the frame, and increases the turning radius of the rear rotor unit. This prevents or at least minimizes incomplete transfer of the swath from the front to the rear rotor unit. Simultaneously, the overall working width of the side-delivery rake, comprised of the working widths of the front and rear rotor units, can be automatically maximized when turning.

[0012] Preferably, the control unit is further configured to regulate the hydraulic supply to the steering cylinder in such a way that the actual value of the steering angle in a second optionally activatable steering mode for generating individual swaths approaches a second target value dependent on the measured caster angle.

[0013] Preferably, the control unit is further configured to control the hydraulic supply to the steering cylinder in such a way that the steering angle in a third optionally activatable steering mode for transport journeys is set to essentially zero (alignment of the longitudinal beam and direction of travel of the rear gyroscope unit essentially identical) and the hydraulic supply to the steering cylinder is then shut off.

[0014] The measured steering angle can also be described as its actual value at the first sensor. Similarly, the actual value of the caster angle corresponds to the caster angle measured by the second sensor.

[0015] Preferably, the control unit is configured to control the hydraulic supply to the steering cylinder in such a way that the actual value of the caster angle in a fourth optionally activatable steering mode for reversing approaches a predetermined minimum value, in particular zero (alignment of the longitudinal member and direction of travel of the front gyroscope unit essentially identical).

[0016] Preferably, the system further comprises a third sensor for measuring a thrust direction angle (thrust direction when reversing) between a drawbar arranged on the front rotary unit and a trailer hitch that can be coupled to a tractor. The control unit is then further configured to control the hydraulic supply such that: the actual value of the caster angle decreases when reversing and the thrust direction angle increases, and in particular approaches zero (alignment of the longitudinal beam and direction of travel of the rear rotary unit essentially identical); the hydraulic supply is only activated when the third sensor detects a turn; and / or the hydraulic supply is not activated when stationary (only when the rotary rake is moving) and is proportional to the driving speed.

[0017] The third sensor, designed for example as a rotary encoder (angle sensor), preferably directly measures the angular position between the drawbar and the hitch or the direction of travel of the tractor (thrust angle of reversing).

[0018] The system can also include a fourth sensor for detecting and / or monitoring reversing movements, which is then specifically designed for non-contact scanning of the surface being driven on, for example optically or by means of radar.

[0019] The side-delivery rake comprises a system according to at least one of the described embodiments and a connection for linking the control unit to an operating terminal, which is arranged, in particular, on a tractor and / or provided in the form of a mobile communication device. The operating terminal could also be arranged on the control unit or elsewhere on the rotary rake.

[0020] The method serves to control the steering of a trailed side-delivery rake, in particular a twin-rotor side-delivery rake, with a front and a rear rotor unit, which are articulatedly connected by means of a longitudinal beam, and with a drawbar arranged on the front rotor unit, wherein the following are continuously, i.e., repeatedly at suitable time intervals: an actual value of a pivot angle formed between the longitudinal beam and the chassis of the rear rotor unit is measured; an actual value of a caster angle formed between the longitudinal beam and the drawbar is measured; the pivot angle is set by means of a hydraulic steering cylinder; and the hydraulic supply to the steering cylinder is electronically controlled.Furthermore, the hydraulic supply is regulated in such a way that the actual value of the steering angle continuously approaches a first target value dependent on the respective actual value of the caster angle as a result of the activation of a first electronically implemented steering mode for generating a side swath.

[0021] This allows the advantages described regarding the system to be achieved.

[0022] The steering angle can be measured with a position sensor as the angular position of the longitudinal member relative to the chassis of the rear gyro unit (directly) or as the length position (retracted or extended position) of the steering cylinder (indirectly). The same applies to the measurement of the caster angle, then relative to the chassis of the front gyro unit or an associated steering cylinder.

[0023] Preferably, therefore, in the first steering mode, the track of the rear gyroscope unit is automatically corrected to the right when it is offset to the left relative to the front gyroscope unit and when cornering to the left, depending on the actual value of the caster angle, viewed in the direction of travel.

[0024] Preferably, the hydraulic supply is regulated as a result of the activation of a second electronically implemented steering mode for generating individual swaths in such a way that the actual value of the steering angle approaches a second target value which depends on the actual value of the caster angle.

[0025] Preferably, the hydraulic supply is controlled as a result of the activation of a third electronically implemented steering mode for transport journeys in such a way that the actual value of the steering angle is essentially set to zero and the hydraulic supply to the steering cylinder is then shut off.

[0026] Preferably, the hydraulic supply is controlled as a result of the activation of a fourth electronically implemented steering mode for reverse driving in such a way that the actual value of the caster angle approaches a predetermined minimum value, in particular zero.

[0027] Preferably, a thrust direction angle formed between a drawbar arranged on the front rotary unit and a trailer coupling device that can be coupled to a tractor is measured. The hydraulic supply is then further controlled such that the actual value of the caster angle decreases during reverse travel and when the thrust direction angle increases, and in particular approaches zero.

[0028] Preferably, the first steering mode is activated at an operating terminal located on a tractor pulling the side-delivery rake and / or connected via radio link. This preferably also applies to the second and third steering modes, provided the respective steering mode is implemented.

[0029] The described directions for track offset, track correction, curve direction, gyro rotation or the like, for example to generate a side swath or single swaths, could each also be completely mirrored (reversal of right / left).

[0030] Preferred embodiments of the invention are illustrated in the drawings. They show: Fig. 1 a schematic circuit diagram of the system; Fig. 2 a schematic top view of a rotary rake with the system during left-hand turning; and Fig. 3 a top view of a structural design of the rotary rake in a straight-ahead position, for example during transport.

[0031] As the Fig. 1 and 2 As can be seen in the overall view, the steering control system 1 is assigned to a trailed side rake2, which for the sake of simplicity is also referred to here only as side rake 2 and in the simplest case is designed as a twin-rotor side rake.

[0032] The side-delivery rake 2 comprises a drawbar 3 and a front rotary unit 4 connected thereto in a manner known in principle, comprising a chassis 4a, a rotary mount 4b, and a rotating gyroscope 4c with a counterclockwise direction of rotation 4d. The side-delivery rake 2 also comprises at least one rear rotary unit 5 with a chassis 5a, an associated rotary mount 5b, and a rotating gyroscope 5c with a counterclockwise direction of rotation 5d. For embodiments with a clockwise direction of rotation of the rotating gyroscopes 4c and 5c, the description applies accordingly, in reverse.

[0033] The front and rear gyroscope units 4, 5 are laterally pivotable and coupled to each other by a longitudinal beam 6, here indirectly via the drawbar 3. This means that the drawbar 3 or the associated front gyroscope mount 4b pulls the rear gyroscope unit 5 behind it by means of the longitudinal beam 6 during normal driving operation.

[0034] The system 1 comprises a first sensor 7, with which a steering angle 8 formed between the longitudinal beam 6 and the chassis 5a or the gyroscope mount 5b of the rear gyroscope unit 5 is measured, and a second sensor 9, with which a caster angle 10 formed between the longitudinal beam 6 and the drawbar 3, the chassis 4a and / or the gyroscope mount 4b of the front gyroscope unit 4 is measured.

[0035] The steering angle 8 is formed here between the longitudinal axis 6a of the longitudinal beam 6 and the respective direction of travel 5e of the rear gyro unit 5, but could in principle also be defined between the longitudinal axis 6a and the axis direction 5f of the rear chassis 5a.

[0036] The first sensor 7 is, for example, arranged on a joint connecting the longitudinal member 6 with the rear gyroscope unit 5, and / or the second sensor 9 is arranged on a joint connecting the longitudinal member 6 with the front gyroscope unit 4, as indicated by way of example. The first and / or second sensor 7, 8 is then designed as a rotary encoder (angle sensor) for measuring the respective angular position.

[0037] System 1 comprises a first hydraulic steering cylinder 11 for adjusting the steering angle 8. The first steering cylinder 11 is, for example, articulated in a manner known in principle to the longitudinal member 6 and to the gyroscope mount 5b of the rear gyroscope unit 5 and is thus also steerably connected to its chassis 5a or the gyroscope mount 5b.

[0038] The rotary rake 2 optionally includes a second hydraulic steering cylinder 12 for adjusting an angle of attack 25 between the chassis 4a of the front rotor unit 4 and the longitudinal axis 3a of the drawbar 3, in the principle known from other systems. The second steering cylinder 12 is articulated to the drawbar 3. The angle of attack 25 allows for a lateral offset to the right or left between the tractor track and the track of the front rotor unit 4.

[0039] The caster angle 10 is defined, for example, between the longitudinal axis 3a of the drawbar 3 and the longitudinal axis 6a of the longitudinal beam 6. The two bearing points of the second steering cylinder 12 are then preferably located on the drawbar 3 and on a control lever 26, which is steerably connected to the chassis 4a of the front gyroscope unit 4 via the axis of rotation of the gyroscope 4c. The second steering cylinder 12 can be manually controlled in a manner known in principle.

[0040] The fact that the first steering cylinder 11 can be pivoted on both sides means that the first sensor 7 could measure not only an angular position but also a length position (extension / retraction position) of the first steering cylinder 11, from which the respective angular position and thus the steering angle 8 can then be unambiguously derived. This too is to be understood as a (in this case indirect) measurement of the steering angle 8 of the described control method.

[0041] As in the Fig. 1 As schematically indicated, system 1 comprises an electronic control unit 13 for controlling / regulating the hydraulic supply 11a ( Fig. 1 ) to the first steering cylinder 11. While the sensors 7, 9 and the first steering cylinder 11 are necessarily components of the side rake 2, the control unit 13, although it is part of the system 1, could in principle also be arranged outside the side rake 2, for example on an associated tractor 30 ( Fig. 2 However, an arrangement on the side rake 2 is advantageous for simplified cable routing, for example using ISOBUS.

[0042] The electronic control unit 13 continuously calculates, i.e., repeatedly at suitable time intervals, the actual values ​​8a of the steering angle 8 measured by the first sensor 7 and the actual values ​​10a of the caster angle 10 measured by the second sensor 9 for the described steering control. The associated signal transmission preferably takes place by means of wiring, for example via ISOBUS, but would in principle also be possible wirelessly via radio connection.

[0043] In the control unit 13, at least one first, optionally activatable steering mode 14 for generating a side swath 14c is provided by suitable programming ( Fig. 2 ) implemented, preferably also a second, optionally activatable steering mode 15 for generating individual swaths (not shown) and / or a third, optionally activatable steering mode 16 for transport journeys (corresponding straight-ahead position of the rotary rake 2 see Fig. 3 ) and / or a fourth optionally activatable steering mode 17 for reversing (not shown).

[0044] The fourth steering mode 17, if implemented, can preferably only be selected starting from the third steering mode 16 or during transport operation. The first to third steering modes 14 to 16 are mutually exclusive, so only one of them can be selected at a time.

[0045] In the first steering mode 14, the control unit 13 regulates the hydraulic supply 11a to the first steering cylinder 11 such that the actual value 8a of the steering angle 8 approaches and ideally aligns with a first target value 8b that depends on the (measured) actual value 10a of the caster angle 10. The first target value 8b lies, for example, in a range between the first steering cylinder 11 being fully retracted and its (in contrast, half-extended) neutral position.

[0046] The first steering mode 14 is used for tracking correction of the rear gyro unit 5 during cornering 14a ( Fig. 2 ) to the left during side swath laying, whereby in the control unit 13 a suitable first setpoint 8b can be selected from a stored table of values ​​and / or calculated using suitable algorithms for different values ​​or ranges of the caster angle 10.

[0047] Accordingly, depending on the driving situation, the driving path of the rear gyroscope unit 5 is automatically corrected towards the outside of the curve by automatically approximating the actual value 8a to the respective first target value 8b when it is offset to the left 14b with respect to the front gyroscope unit 2 and when cornering 14a, i.e. depending on the respective measured caster angle 10.

[0048] This ensures that the crop picked up by the rake 4c of the front rotor unit 4 is effectively transferred to the rake 5c of the rear rotor unit 5 and deposited as a common side swath 14c, which is in the Fig. 2 is indicated schematically.

[0049] In the second steering mode 15, the control unit 13 regulates the hydraulic supply 11a such that the actual value 8a of the steering angle 8 approaches a second target value 8c, which depends on the (measured) actual value 10a of the caster angle 10. The second target value 8c lies, for example, in a range between the first steering cylinder 11 being fully extended and its (in contrast, half-retracted) neutral position.

[0050] This also causes a tracking correction of the rear gyroscope unit 5, but with its rightward offset (not shown) relative to the front gyroscope unit 2 and when cornering to the right (not shown), in order to maintain and in particular optimize the lateral distance of the swath placement in suitable areas, analogous to the control principle described for the first steering mode 14.

[0051] In the third steering mode 16, the control unit 13 controls the hydraulic supply 11a in such a way that the actual value 8a of the steering angle 8 is essentially set to zero, i.e., to the straight-ahead position of the rear gyroscope unit 5 with respect to the longitudinal member 6, and the hydraulic supply 11a to the steering cylinder 11 is then shut off in order to lock its position against external forces.

[0052] In the fourth steering mode 17, the control unit 13 regulates the hydraulic supply 11a of the first steering cylinder 11 in order to minimize the actual value 10a of the caster angle 10 (indirectly in this way), i.e., to set it as close to zero as possible, corresponding to a straight-ahead position of the longitudinal beam 6 with respect to the front rotary unit 4 or the drawbar 3. This minimization of the angle serves to approximate and, if possible, align the driving behavior of the rotary rake 2 when reversing with that of a single-axle trailer.

[0053] Alternatively or additionally, the second steering cylinder 12 could also be controlled by the control unit 13 to (directly) minimize the caster angle 10 when reversing.

[0054] The first steering cylinder 11 and, if applicable, the second steering cylinder 12 are electronically controlled based on sensors 7, 9, in contrast to hydraulic control using a hydraulic master cylinder and / or mechanical control via cams or the like. The described track correction of the rear gyroscope unit 5 in the first and / or second steering mode 14, 15 is possible with relatively little equipment effort thanks to such electronic control and can also be flexibly adapted to the respective requirements by programming the control unit 13.

[0055] To support the fourth steering mode 17, the system 1 can include an optional third sensor 18 for measuring a thrust direction angle 19 formed between the longitudinal axis 3a of the drawbar 3 and a pivotally connected trailer hitch 20, or the direction of travel 31 (orthogonal to the transversely oriented trailer hitch 20) of an associated tractor 30. As the Fig. 2 As can be seen, the attachment device 20 is designed, for example, as a trailer rail and can then be coupled to a tractor 30 in a known manner, for example by anchoring it to the lower links of a three-point linkage.

[0056] The third sensor 18 is particularly advantageous when stationary or when reversing and then provides, for example, at least one actual value 19a ( Fig. 1 ) of the thrust direction angle 19 to the control unit 13.

[0057] According to Fig. 1 System 1 for controlling the hydraulic supply 11a to the first steering cylinder 11 can include a directional control valve 21 and a shut-off valve 22, each of which is electronically controlled by the control unit 13. The directional control valve 21 and the shut-off valve 22 are connected between the first steering cylinder 11 and the associated tractor hydraulics 32 (of the tractor 30) and can be located on the rotary rake 2.

[0058] System 1 also includes an operating terminal 23, which is used to operate the control unit 13, for example, to select one of the described steering modes 14 to 17. The operating terminal 23 can, in principle, be part of the rotary rake 2, but is preferably located on the associated tractor 30 so that it can be operated by the tractor driver while driving. Alternatively, the operating terminal 23 could be provided in the form of a mobile device or the like.

[0059] System 1 can also include a fourth sensor 24 that scans the surroundings without contact, for example optically or via radar, in order to detect and / or monitor the driving speed and / or a reverse movement and to trigger or activate the fourth steering mode 17 accordingly. The fourth sensor 24 can communicate with the control unit 13 and / or the operating terminal 23, for example, wirelessly or via ISOBUS using suitable wiring. In principle, signals for detecting and / or monitoring a reverse movement could also be received by the associated tractor 30 in other ways.

[0060] System 1 can operate as follows, for example: The required steering force at the steering cylinder 11 is generated by the associated tractor hydraulics 32. For this purpose, the hydraulics are switched to constant oil circulation (in operating position), for example, according to the "open center" principle, ideally according to the "closed center" principle. A constant supply of hydraulic oil is not required and, in open-center systems, leads to overheating and reduces efficiency. Only at a specific steering angle (corresponding to the depicted thrust direction angle 19) and duration of application (bandwidth) does System 1 (using a suitable algorithm) detect a turn and activate the hydraulic flow. This avoids constant, unnecessary steering corrections.

[0061] At the operating terminal 23, the driver selects a desired working strategy, for example, one of the described steering modes 14 to 17. This selection is transmitted to the control unit 13, for example, via ISOBUS. The rotary rake 2 can have a suitable connection (not shown) for the operating terminal 23. The connection can be configured for an internal, external (e.g., to the tractor), wired, and / or wireless connection of the operating terminal 23.

[0062] After selecting the third steering mode 16, i.e., during a transport journey, the first sensor 7 continuously determines the actual value 8a of the steering angle 8, possibly also indirectly via the current position of the first steering cylinder 11, and transmits the corresponding sensor values ​​to the control unit 13. This controls the hydraulic supply 11a, for example via the directional control valve 21, so that the steering cylinder 11 reaches its position for the transport journey, i.e., the straight-ahead position of the rear gyroscope unit 5. The locking valve 22 locks this steering cylinder position against external forces.

[0063] When the chassis and drawbar cylinders are fully extended and pressurized for transport, a further monitoring signal can be generated to confirm the third steering mode 16.

[0064] After selecting the first steering mode 14, i.e., for generating a side swath 14c, the steering cylinder 11 retracts at least partially, and possibly completely. During driving, the steering angle 8 and the caster angle 10 are continuously determined by means of the associated first and second sensors 7, 9 and the control unit 13.

[0065] When cornering (here, cornering to the left), the actual value 10a of the caster angle 10 typically varies. For individual angle values ​​and / or angle ranges, the control unit 13 assigns initial target values ​​8b of the steering angle 8 to this value. If the respective actual value 8a of the steering angle 8 deviates from the currently assigned initial target value 8b, the control unit 13 actuates the directional control valve 21 such that the first steering cylinder 11 is actuated by the tractor hydraulics 32 and thus adjusted accordingly, thereby changing the steering angle 8 until its actual value 8a reaches the currently valid initial target value 8b or at least approaches it to a suitable extent.

[0066] In other words, the directional control valve 21 is controlled such that the first steering cylinder 11 extends to a predetermined correction value, which is determined by comparing it with the actual value 8a measured by the first sensor 7. The described control loop thus optimizes the rotor overlap and consequently the swath transfer between the front and rear rotor units 4, 5. The caster angle 10 results from the swept path of the front rotor chassis 4a and changes only during normal driving. No control is to take place when stationary or at crawling speeds. The control of the directional control valve 21 can be proportional to the driving speed.

[0067] After selecting the second steering mode 15, i.e., when generating two individual swaths, the first steering cylinder 11 extends at least partially, and possibly fully. During operation, the steering angle 8 and the caster angle 10 are continuously determined by means of the associated first and second sensors 7, 9 and the control unit 13. A [missing information] in the Fig. 3 The rear swath former 2a, shown as an example, is then swung upwards out of the potential collision area.

[0068] When cornering (here, cornering to the right), the actual value 10a of the caster angle 10 typically varies. For individual angle values ​​and / or angle ranges, the control unit 13 assigns second target values ​​8c of the steering angle 8 to this value. If the respective actual value 8a of the steering angle 8 deviates from the currently assigned second target value 8c, the control unit 13 actuates the directional control valve 21 such that the first steering cylinder 11 is actuated by the tractor hydraulics 32 and thus adjusted accordingly, thereby changing the steering angle 8 until its actual value 8a reaches the currently valid second target value 8c or at least approaches it to a suitable extent.

[0069] In other words, the directional control valve 21 is then controlled so that the first steering cylinder 11 retracts to a predetermined correction value, which results from a comparison with the actual value 8a determined by the first sensor 7. The described control loop thus optimizes the track of the rear rotor unit 5 and consequently the distance between the swath placement at the front and rear rotor units 4, 5.

[0070] In principle independent of the described electronic lane correction in the first and / or second steering mode 14, 15, the system 1 in the fourth steering mode 17 enables simplified handling of the rotary rake 2 when reversing, for which otherwise a considerable amount of driver practice is required. This makes the handling similar to that of a single-axle trailer.

[0071] The fourth steering mode 17 is preferably only activatable in transport position, for example starting from the third steering mode 16, and with recirculating hydraulics. For example, the fourth sensor 24 and / or the tractor 30 detects a reverse movement and the associated speed and transmits a corresponding signal to the control unit 13 to activate the reverse control in the fourth steering mode 17 (after its selection) and to carry it out, for example, as follows.

[0072] If the thrust direction angle 19 changes during reverse travel between the direction of travel 31 of the tractor 30 and the drawbar 3, this generates a signal at the third sensor 18, which is preferably designed as an angle sensor (rotary encoder).

[0073] The respective axis direction 5f of the rear gyroscope unit 5 causes a change in the caster angle 10 during further reverse travel, the actual value 10a of which is detected by the second sensor 9 and transmitted to the control unit 13.

[0074] For individual angle values ​​and / or angle ranges, the caster angle 10 is then assigned third setpoint values ​​8d of the steering angle 8 in the control unit 13. If the respective actual value 8a of the steering angle 8 deviates from the currently assigned third setpoint value 8d, the control unit 13 controls the directional control valve 21 such that the first steering cylinder 11 is actuated by the tractor hydraulics 32 and thus adjusted accordingly, thereby reducing the caster angle 10, preferably until its actual value 10a reaches zero, i.e., until the drawbar 3 and the longitudinal beam 6 are aligned parallel to each other.

[0075] The described steering correction for reverse driving could in principle be carried out via the second steering cylinder 12 on the front gyroscope unit 4 or supported by its suitable control.

[0076] The second steering cylinder 12 can otherwise be controlled on the tractor side in a generally known manner, i.e., when driving forward, which is therefore not described in detail.

[0077] Reversing around a curve presents a particular challenge for the driver. System 1 can therefore include a reversing aid that displays guidelines for a predicted reversing route on the control terminal 23, enabling the driver to select the most ideal steering angle and avoid multiple forward and backward maneuvers.

[0078] Preferably, a camera (not shown) is mounted at the rear of the tractor, which focuses on the implement (rotary rake) and records the position of rotor units 4 and 5. Optical markings on rotor units 4 and 5 can facilitate such position determination.

[0079] Furthermore, a steering sensor signal from the tractor 30 is provided and compared with the sensor values ​​of the drawbar position, here with at least one actual value 19a of the thrust direction angle 19, and with the positions of the gyroscope units 4, 5 in the control unit 13 determined by image evaluation of the camera images (so) and compared with the respective target values. Such target values ​​can be based on AI databases, which, for example, also allows obstacles in the camera image to be detected and alarm notifications to be issued.

[0080] The steering cylinder 11 is then additionally controlled so that the reverse driving curves approximate the guidelines of the reversing aid and thus relieve the driver.

Claims

1. System (1) for steering control of a pulled side rake (2) with a front and a rear rotary unit (4, 5), which are joint connected by means of a longitudinal member (6), and with a drawbar (3) arranged on the front rotary unit (4), the system (1) comprising: - a first sensor (7) for measuring an articulation angle (8) formed between the longitudinal member (6) and the chassis (5a) of the rear rotary unit (5); - a second sensor (9) for measuring a caster angle (10) formed between the longitudinal member (6) and the drawbar (3); - a hydraulic steering cylinder (11) for adjusting the articulation angle (8); and - an electronic control unit (13) for controlling the hydraulic supply (11a) to the steering cylinder (11), wherein the control unit (13) is arranged to control the hydraulic supply (11a) in such a way that the actual value (8a) of the articulation angle (8) in a selectively activatable first steering mode (14) for generating a lateral swath approaches a first setpoint value (8b) dependent on the measured caster angle (10).

2. System according to claim 1, wherein the first steering mode (14) is implemented in the control unit (13) in such a way that the track of the rear rotary unit (5) is automatically corrected to the right as a function of the measured caster angle (10), viewed in the direction of travel, when the rear rotary unit (5) is offset to the left with respect to the front rotary unit (4) and when cornering to the left.

3. System according to one of the preceding claims, wherein the control unit (13) is furthermore set up to control the hydraulic supply (11a) in such a way that the actual value (8a) of the steering angle (8) in a second steering mode (15), which can be activated as desired, for generating individual swaths approaches a second setpoint value (8c) which is dependent on the actual value (10a) of the caster angle (10).

4. System according to one of the preceding claims, wherein the control unit (13) is further arranged to control the hydraulic supply (11a) in such a way that the actual value (8a) of the steering angle (8) in a third optionally activatable steering mode (16) for transport travel is set essentially to zero and the hydraulic supply (11a) to the steering cylinder (11) is then shut off.

5. System according to one of the preceding claims, wherein the control unit (13) is furthermore set up to control the hydraulic supply (11a) in such a way that the actual value (10a) of the caster angle (10) approaches a predetermined minimum value, in particular zero, in a fourth optionally activatable steering mode (17) for reverse travel.

6. System according to one of the preceding claims, further comprising a third sensor (18) for measuring a thrust direction angle (19) between the drawbar (3) and a hitch (20) which can be coupled to a tractor (30), wherein the control unit (13) is further arranged to control the hydraulic supply (11a) in such a way that: the actual value (10a) of the caster angle (10) decreases and, in particular, approaches zero during reverse travel and increase of the thrust direction angle (19); and / or the hydraulic supply (11a) is only activated when cornering is detected by means of the third sensor (18); and / or the hydraulic supply (11a) is, on the one hand, not carried out at a standstill and, on the other hand, proportional to the travel speed.

7. Side rake (2) comprising a system (1) according to at least one of the preceding claims and a connection for connecting the control unit (13) to an operator terminal (23) arranged in particular on a tractor (30) and / or provided in the form of a mobile radio device.

8. Method for steering control of a trailed side rake (2) with a front and a rear rotary unit (4, 5), which are articulatedly connected by means of a longitudinal member (6), and with a drawbar (3) arranged on the front rotary unit (4), wherein in each case running: - an actual value (8a) of an articulation angle (8) formed between the longitudinal member (6) and the running gear (5a) of the rear rotary unit (5) is measured; - an actual value (10a) of a caster angle (10) formed between the longitudinal member (6) and the drawbar (3) is measured; - the steering angle (8) is set by means of a hydraulic steering cylinder (11); and - the hydraulic supply (11a) to the steering cylinder (11) is electronically controlled, wherein the hydraulic supply (11a) is controlled in such a way that the actual value (8a) of the steering angle (8) continuously approaches a first setpoint value (8b) dependent on the respective actual value (10a) of the caster angle (10) as a result of activation of a first electronic steering mode (14) for generating a side swath.

9. Method according to claim 8, wherein the track of the rear rotary unit (5) is automatically corrected towards the outside of the curve as a function of the actual value (10a) of the caster angle (10) when the rear rotary unit (5) is offset to the left with respect to the front rotary unit (4) and when cornering to the left in the first steering mode (14).

10. Method according to claim 8 or 9, wherein the hydraulic supply (11a) is controlled as a result of an activation of a second electronic steering mode (15) for generating individual swaths in such a way that the actual value (8a) of the steering angle (8) approaches a second setpoint value (8c) dependent on the actual value (10a) of the caster angle (10).

11. Method according to one of claims 8 to 10, wherein the hydraulic supply (11a) is controlled as a result of an activation of a third electronic steering mode (16) for transport travel such that the actual value (8a) of the steering angle (8) is set to zero and the hydraulic supply (11a) to the steering cylinder (11) is then shut off.

12. Method according to one of claims 8 to 11, wherein the hydraulic supply (11a) is controlled as a result of an activation of a fourth electronic steering mode (17) for reversing in such a way that the actual value (10a) of the caster angle (10) approaches a predetermined minimum value, in particular zero.

13. Method according to one of claims 8 to 12, wherein a thrust direction angle (19) formed between a drawbar (3) arranged on the front rotary unit (4) and a towing device (20) which can be coupled to a tractor (30) is measured, and wherein the hydraulic supply (11a) is controlled in such a way that the actual value (10a) of the caster angle (10) decreases and in particular approaches zero during reverse travel and increase of the thrust direction angle (19).

14. Method according to any one of claims 8 to 13, wherein the first steering mode (14) is activated at an operator terminal (23) which is arranged on a tractor (30) pulling the side rake (2) and / or is connected by radio link.

15. Method according to any one of claims 8 to 14, wherein it is determined whether the respectively preselected steering mode (14, 15, 16, 17) corresponds to values of the measured steering angle (8) and / or caster angle (10) and / or thrust direction angle (19) and / or to measured values of a speed and driving direction sensor (24), and wherein, in the event of a lack of correspondence, an optical and / or acoustic warning signal is emitted and / or at least one critical operating state is automatically prevented, in particular in that a swath former (2a) is automatically pivoted out of a collision plane.