Improved hydraulic device

Abstract

Method (19) for controlling a hydraulic device (1) with a mounting base (5), a pivoting arm (3) arranged pivotably on the mounting base (5), a Z-kinematics (2) arranged on the pivoting arm (3) which is designed and configured to tilt a tool mounting device (10), wherein the tool mounting device (10) is pivotably attached to the pivoting arm (3), wherein the pivot arm (3) is moved by means of at least one lifting hydraulic piston (7), wherein the lifting hydraulic piston (7) is connected to the pivot arm (3) and the mounting base (5), and wherein the Z-kinematics (2) is moved by means of at least one tilting hydraulic piston (11), wherein the tilting hydraulic piston (11) is connected to a lever of the Z-kinematics (2) and the mounting base (5), wherein, after input of an input control signal to change the position of the lifting hydraulic piston (7), a compensation signal is automatically generated and applied to the tilting hydraulic piston (11) to substantially maintain the orientation of the tool mounting device (10), wherein the compensation command is automatically generated by a control device by outputting a suitable control command to the tilting hydraulic piston (11) using a mathematical model of the hydraulic device (1) based on the input control signal for the lifting hydraulic piston (7), and the control device thereby performs a suitable rotational compensation, where the compensation command can be individually selected to be limited or increased by a percentage.

Description

[0001] The invention relates to a method for controlling a hydraulic device which has a Z-kinematic mechanism. The invention further relates to a control device, a hydraulic device, and a work vehicle.

[0002] Whenever large quantities of bulk materials need to be handled, particularly in mines, on construction sites, in quarries, in agriculture, and in storage areas with large piles (to name just a few examples), telescopic handlers, telescopic wheel loaders, wheel loaders, and similar machines are frequently used. In particular, these machines can be used without extensive infrastructure. Consequently, they can be deployed much more flexibly and in areas where stationary structures such as overhead cranes, large storage bunkers, underground bunkers, or the like, despite their inherent advantages, are not practical.

[0003] The basic design of such telescopic handlers, telescopic wheel loaders, and general wheel loaders consists of a movable vehicle body on wheels and, in some cases, tracks. An arrangement of levers and pivoting arms is mounted on the vehicle body and can be pivoted. Typically, the lever arrangement is moved by hydraulic pistons, although different actuators can also be used. Movement of the hydraulic pistons causes the parts of the lever arrangement to move upwards and downwards. These parts are located on the side opposite the pivot point of the pivoting arm. Tilting attachments, such as a bucket, excavator bucket, forks, or similar implements, are usually mounted there. By tilting the bucket / excavator bucket / forks (or other attachment), the material to be moved can be either moved into or out of the excavated area.The device must be held in place in such a way that the vehicle can be moved without the goods being lost, or in such a way that the goods are released. For example, in the case of a shovel, the shovel can be positioned in a trough-like manner, allowing gravel or other types of solid bulk materials to be moved. By tilting the shovel, the gravel can be emptied at its destination. This destination could be a truck, a dump truck, a railway wagon, a pile of solid bulk material, and / or similar. Needless to say, such vehicles are very widespread and successfully used in a wide range of technical applications. Accordingly, the manufacture of such machines is an attractive economic sector.

[0004] Standard machines, however, require well-trained operators. The problem lies in the fact that, due to the machine's design and construction, controlling the various hydraulic pistons does not only have the desired effect on the directly driven parts of the machine, particularly the main swivel arm or similar components. Instead, side effects typically occur, resulting in various and undesirable types of movement. Up to now, such side effects have either had to be tolerated and / or compensated for by appropriate manual control of the machine by well-trained personnel.

[0005] To give an example: when the bucket of a telehandler needs to be raised, this is achieved by actuating the hydraulic pistons, which raises or lowers the main swing arm (more precisely: the parts of the main swing arm that are opposite to its mounting hinge). However, since the main swing arm is pivotally mounted to the vehicle body, actuating the hydraulic cylinders not only raises or lowers the swing arm and thus the attachments (such as a bucket), but also causes a certain tilting motion of the bucket. Particularly in the case of significant changes in height, this can lead to spillage of goods contained in the bucket. This is, of course, undesirable.It is even more problematic when goods are transported on the forks of a telehandler (to give another example), as it is then possible that goods stored on a pallet being moved by this telehandler may fall off the forks and / or the pallet.

[0006] With standard machines, the operator of the telehandler (or any other type of machine) must take these side effect movements into account and compensate for them by appropriately controlling a suitable compensating tilting movement of the shovel, fork, excavator bucket, and the like.

[0007] It is obvious that such orchestrated control of different settings of various levers and pedals is not easy and requires sufficient training and experience on the part of the operator. Even then, this usually leads to operator fatigue after relatively short periods. Furthermore, even well-trained operators can make incorrect inputs, which can lead to spillage of bulk materials, for example.

[0008] Various proposals have already been made in the prior art to solve this problem for the operators of such machines.

[0009] US 6,233,511 B1, for example, proposes the use of electronic digital control in connection with a loader that has various conventional mechanical components. The hydraulic valves are electronically controlled in such a way that the control system rotates the bucket to maintain a substantially uniform angle between the bucket and the loader body (i.e., a constant orientation of the bucket is maintained) when the operator commands the tractor to raise or lower the bucket. US 9,822,507 B2 and US 6,763,619 B2 pursue a similar approach. However, the solutions implemented so far are limited to certain types of kinematics, such as P-kinematics.

[0010] US Patent 6,309,171 B1 describes a mobile construction machine with a front loader attachment, featuring a lifting frame rotatably mounted at its rear end to a front frame section of the loader. The lifting frame can be raised and lowered by means of a lifting cylinder. A work bucket, fork, or the like is rotatably coupled to the front of the lifting frame. A rocker arm is rotatably mounted in a central area of ​​the lifting frame. The lower end of the rocker arm is pivotally connected at a rocker cylinder coupling point to a rocker cylinder, which at its other end is connected at a rocker cylinder pivot point to the frame section (13). The upper end of the rocker arm is coupled at a rocker rod pivot point to a rocker rod, which at its other end is coupled to the work bucket.By placing the point above the blade pivot point, the kinematic system is to be further improved, which is achieved through special geometric relationships.

[0011] US 2014 / 0107841A1 proposes a control system for driving a linkage system, such as the articulated arm of a hydraulic excavator, which combines the automation of routine tasks with real-time correction by a human supervisor. One embodiment uses a differential control architecture with an inverse Jacobian matrix. This avoids the need to model the desired trajectory of the end effector in system space.

[0012] US 2018 / 0202126A1 describes a self-leveling mechanism for controlling a tilting movement of a device attached to a device connection of the main arm of a lifting device of a construction machine, preferably a wheel loader, when the main arm is pivoted. The self-leveling mechanism is configured to at least partially compensate for any tilting movement of the device.

[0013] One problem with limiting the design to P-kinematics (or possibly other types of kinematics) compared to Z-kinematics is that, due to the laws of leverage, a certain force exerted by the tilting hydraulic cylinder is transmitted directly to the bucket / excavator bucket / forks without amplification. Furthermore, such kinematics typically require more installation space compared to Z-kinematics. These are all significant disadvantages.

[0014] An application of the “automatic compensation idea” (as proposed, for example, in US 6 233 511 B1, US 9 822 507 B2 and US 6 763 619 B2) to Z-kinematics has not yet been proposed, possibly due to the more complicated and, in particular, ambiguous modeling of the motion behavior of at least some designs of Z-kinematics.

[0015] These and other problems can be solved by using the present idea.

[0016] One object of the present application is therefore to propose a method for controlling a hydraulic device having a Z-kinematic mechanism arranged on a pivot arm, such that the method is improved compared to previously known methods for operating a hydraulic device of this type. A further object of the present invention is to propose a control device that is improved compared to control devices known in the prior art. A further object of the invention is to propose a hydraulic device that is improved compared to hydraulic devices known in the prior art. A further object of the present invention is to propose a work vehicle that is improved compared to work vehicles known in the prior art.

[0017] These tasks are solved by a method for controlling a hydraulic device according to claim 1, a control device according to claim 12, a hydraulic device according to claim 13, or a work vehicle according to claim 14.

[0018] It is therefore proposed to implement a method for controlling a hydraulic device with a mounting base, a swivel arm pivotably arranged on the mounting base, and a Z-kinematics arranged on the swivel arm, wherein the Z-kinematics is designed and configured to tilt a tool mounting device, wherein the tool mounting device is pivotably attached to the swivel arm, in such a way that the swivel arm is moved by at least one lifting hydraulic piston attached to the swivel arm and the mounting base, and wherein the Z-kinematics is moved by at least one tilting hydraulic piston connected to a lever of the Z-kinematics and to the mounting base.After inputting a control signal to change the position of the lifting hydraulic piston, a compensation signal is automatically generated and applied to the tilting hydraulic piston to essentially maintain the position of the tool clamping device. The compensation command, based on the input control signal for the lifting hydraulic piston, is automatically generated by a control device by outputting a suitable control command to the tilting hydraulic piston using a mathematical model of the hydraulic device. The control device then performs appropriate rotational compensation. The magnitude of the compensation command can be individually selected and either limited or amplified as a percentage. The Z-kinematics proposed here have the advantage that, thanks to the laws of leverage, the force applied by the respective hydraulic piston can typically be amplified (and / or at least remain constant).In this way, the hydraulic piston in question can be smaller, the hydraulic oil pressure can be lower, the tilting force of the bucket / excavator bucket / fork (or the tool mounting device for attaching such or different tools) can be high, and the kickback forces of the tool against the hydraulic piston can be reduced (for example, when a forward movement of a telehandler pushes a bucket into a pile of relatively large stones, etc.). Furthermore, the installation space required for a Z-bar linkage typically offers certain advantages. Z-bar linkages are typically designed such that a rotary lever is rotatably mounted on the mounting base. The rotatable mounting is usually located in a central area of ​​the rotary lever.Typically, the mounting base of the rotary lever is a pivot arm, while the pivot arm is usually mounted to a vehicle body or similar structure in a pivotable manner. However, a different type of mounting and / or a different mounting base is also possible for the Z-bar linkage. Typically, the tilting hydraulic piston, whose main function is to move the various parts of the Z-bar linkage, and thus the tool mounting device and ultimately the tool attached to it (possibly including the goods being moved), is attached at one end to a first end of a rotary lever, while its other end is rotatably mounted to the mounting base of the hydraulic device (typically a vehicle body). The second end of the rotary lever (opposite to the first end relative to the pivot point) is usually directly or indirectly (i.e.,(possibly using a further lever-like device) is connected to the tool mounting device and / or the attached tool. By using a suitable ratio of the distances of the relevant end sections to the relevant pivot point (length of the relevant sections of the pivot lever), a suitable increase (if any) in the driving forces can be easily achieved. The pivot arm, which is pivotally mounted on the mounting base (such as a vehicle body or the like), is driven by a hydraulic piston, which is connected at one end to the pivot arm and at the opposite end to the mounting base (such as a vehicle body). Its main function is to move the tool mounting device / attached tool up and down.Due to the typically pivotable mounting of the swivel arm on its base, an undesirable additional movement (a kind of side effect movement) is usually induced in the swivel arm, at least for a certain range of positions. More precisely, an upward and downward movement of the swivel arm will typically also lead to a certain forward and backward movement of the tool clamping device / the mounted tool. Additionally and / or alternatively, an upward and downward movement of the swivel arm will also typically lead to a certain change in orientation, i.e., a certain rotational movement of the tool clamping device / the mounted tool, unless special compensating means are provided.As proposed here, such compensation with respect to the tool's orientation is performed automatically when an operator commands an up / down movement of the swivel arm. The orientation compensation can also be performed, at least partially, mechanically. Typically, (largely) logical compensation is preferred, where logical compensation means that a control device or similar device automatically performs appropriate rotational compensation by issuing a suitable control command to the tilting hydraulic piston when the operator commands an up / down movement of the swivel arm. In this way, the operation of the device can be simplified, additional work resulting from the unintentional spillage of transported goods can be avoided, and accidents caused by falling goods can potentially be prevented as well.The compensation is performed, at least in part, using a mathematical model of the hydraulic device. This model can preferably be implemented during the device's manufacturing process, for example, in the production facility. The (electronic) control system can then be used to automatically calculate, based on the mathematical model / geometric considerations upon which the mathematical model is based and using the device's current position, that a specific commanded action of an upward / downward movement will require a specific corrective control of the tilting hydraulic piston. Admittedly, from an academic standpoint, the corrective control is not perfect, i.e.,Despite the corrections, a certain, usually significantly reduced, rotation of the tool clamping device / attached tool may occur (under normal operating conditions, this will only happen at a negligible level). The advantage of the proposed idea of ​​using a correction based on a mathematical model is that it is fast and without any time delay (which can occur when a sensor signal / angle signal / position signal is first read, interpreted, and then a correction control is calculated and commanded). For the sake of completeness, it should be mentioned that, depending on the forces the arrangement is designed to withstand, there may be one, two, three, four, or even more devices of the appropriate type.For example, a single swivel arm (a single rod) may be used. If larger geometries and / or greater forces are involved, two swivel arms may be employed (which is the typical number). In the case of particularly heavy loads, three or four swivel arms may also be considered. The devices in question may or may not be connected to each other (for example, in a truss-like manner). The foregoing applies not only to passive components (rods / swivel levers, tools, fastening devices, etc.) but also to active components such as hydraulic pistons and the like.

[0019] Preferably, the method is applied to a hydraulic device, in particular to a hydraulic device having a Z-kinematic mechanism that is operated on opposite sides of a dead center position of the device in question (hydraulic device, Z-kinematic mechanism, etc.), preferably across a dead center position of the device. Certain parts of certain devices, in particular the connection between a rotary lever and a connecting lever (where the connecting lever typically connects an end region of the rotary lever to a suitable part of the tool mounting device and / or the tool), exhibit a so-called dead center. This can be understood to mean that a movement of the device in question in a certain direction of rotation causes a kind of back-and-forth movement of the connected device, i.e.,First, there is a movement in a specific translational direction, a halt with respect to that direction, and a reversal of the direction of movement in that direction if the rotational movement continues. For the sake of completeness, it should be noted that the translational movement in the first direction is usually (though not necessarily) superimposed on a translational movement in a second direction (which typically does not reverse its direction of movement). Typically, however, the velocity of movement in this second direction is essentially constant near the dead center position. Furthermore, the first and second directions of movement are typically perpendicular to each other. Due to the mechanical design of the components involved, the probability of the described situation occurring is particularly high in Z-type hydraulic kinematics.This design is particularly advantageous because the forces that can be applied / transmitted are typically very high in the dead center position. Furthermore, if a Z-axis kinematic mechanism is operated in or across the dead center position, the Z-axis kinematic mechanism can typically be designed to be particularly compact, which is also beneficial.

[0020] It is further proposed to carry out the procedure when a shovel, fork, excavator bucket, and / or grapple can be attached to (is attached to) the tool mounting device, and / or when the hydraulic device forms part of a wheel loader, telescopic wheel loader, telehandler, backhoe, excavator, and / or forklift. In this case, the proposed procedure demonstrates its intrinsic advantages and properties particularly well. For the sake of completeness, it should be noted that the devices in question may be directly connected to certain parts of the hydraulic device (or at least to certain parts of the devices in question). Typically, however, the devices in question are attached to a tool mounting device of the hydraulic device.

[0021] Furthermore, it is proposed that the hydraulic device be mounted on a vehicle and / or that the mounting base be a vehicle body and / or that the mounting base preferably be permanently connected to a vehicle body. In this way, the method proposed here can demonstrate its intrinsic advantages particularly well.

[0022] Furthermore, it is proposed that the input control signal be provided by a human operator. The human operator can be seated in or on the machine, or operate the machine remotely. A combination of human control and autonomous driving can be used, particularly in the case of a remote control device, where the human operator might only specify the destination or certain aspects of the route, while the autonomous driving logic fills in the missing commands.

[0023] It is further proposed to implement the method such that the control commands are influenced by at least one sensor signal, in particular a position sensor signal and / or an angle sensor signal. Although the main correction function—as described above—is essentially based on a mathematical model of the hydraulic device, verification and / or fine-tuning (improved correction effect) can be performed by using at least one sensor signal as an additional input. In particular, the sensor signal can be the output of a position sensor and / or an angle sensor, preferably measuring certain aspects of the hydraulic device, such as position, relative arrangement to each other, etc. This can relate to a direct and / or indirect measurement of the orientation of the tool mounting device and / or the orientation of the mounted tool.However, additional sensors (position sensors / angle sensors) can also be used for all / a majority / some / several of the different parts of the hydraulic device. This information can be used to determine the current position of the respective parts relative to each other, which can then be used as input for the mathematical model of the hydraulic device used to perform the correction function. For example, if the hydraulic device is in a certain position, a lift command of a specific magnitude might require a different corrective response from the tilting hydraulic cylinder compared to a different, second position of the hydraulic device.

[0024] In particular, the method can be used such that the Z-kinematics comprise a rotary lever and a connecting lever, wherein the rotary lever is pivotably connected at its central region to the pivot arm; at one of its first end regions to the tilting hydraulic piston; and at its second end region to the connecting lever; and wherein the connecting lever is connected at one of its first end regions to the rotary lever and at its second end region to the tool clamping device. In particular, the method proposed herein can demonstrate its intrinsic advantages and properties especially well with such a device.

[0025] It is further proposed to carry out the procedure in such a way that an angle ϕ1 between the line OE, which connects the points O and E, and the line EJ, which connects the points E and J, is determined using the formula ϕ1=cos−1(|JE|2+|OE|2−|OJ|22⋅|JE|⋅|OE|) The calculation is performed where O is the hinge point between the swivel arm and the mounting base, E is the hinge point between the swivel arm and the tool clamping device, and J is the hinge point between the connecting lever of the Z-kinematics and the tool clamping device. In this way, the mathematical model can be easily implemented and / or an advantageous correction function can be applied.

[0026] Similarly, it is proposed to use the procedure in such a way that an angle ϕ2 between the line OJ connecting points O and J and the line EJ connecting points E and J is determined using the formula ϕ2=cos−1(|OJ|2+|JE|2−|OE|22⋅|OJ|⋅|JE|) The calculation is performed where O is the hinge point of the swivel arm and the mounting base, E is the hinge point of the swivel arm and the tool clamping device, and J is the hinge point of the connecting arm of the Z-kinematics and the tool clamping device. In this way, the mathematical model can be easily implemented and / or an advantageous correction function can be applied.

[0027] It is further proposed to carry out the procedure in such a way that an angle ϕ3 is determined between the line OJ, which connects the points O and J, and the line OE, which connects the points O and E, using the formula ϕ3=cos−1(|OJ|2+|OE|2−|JE|22⋅|OJ|⋅|OE|) The calculation is performed where O is the hinge point of the swivel arm and the mounting base, E is the hinge point of the swivel arm and the tool mounting device, and J is the hinge point of the connecting lever of the Z-kinematics and the tool mounting device. In this way, the mathematical model can be easily implemented and / or an advantageous correction function can be applied.

[0028] As mentioned, the compensation command can be individually limited or increased as a percentage. Furthermore, it is proposed that the compensation command be limited in its range. In particular, the compensation can be limited to a specific fraction of the full compensation, for example, up to / a maximum of (possibly including or excluding) 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 10%. Conversely, it can also be advantageous to use overcompensation, for example, up to / at least (possibly including or excluding) 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 250%, 300%, 350%, 400%, 450%, or 500%. The amount can be chosen by the manufacturer, a maintenance mechanic, the employer, or the operator themselves.It is particularly important to note that a person accustomed to compensating for alignment changes through manual control with a suitable correction signal may be confused by the proposed method, which exhibits automatic compensation behavior. Accordingly, the operator may be surprised and / or the proposed method may even be counterproductive (especially if "full" compensation is performed). Using individually selectable percentage compensation can be helpful in phasing out the manual compensation behavior of today's experienced operators. Additionally and / or alternatively, it is also possible for the amount of at least partial compensation to depend on specific ranges of movement.Accordingly, compensation can be implemented for a specific range of movements, whereas no compensation is performed (or compensation is performed only to a limited extent) when this range is exceeded.

[0029] This can be based on any consideration, for example, considerations regarding the mechanical ability of the hydraulic device to perform movements.

[0030] Furthermore, a control device is proposed that is designed and configured to carry out a procedure according to the previous proposals. The control device in question can also be adapted in accordance with the previous description. Typically, such a control device exhibits the same advantages and characteristics as described above, at least by analogy. In particular, the control device can be an electronic control device.

[0031] Furthermore, a hydraulic device is proposed that includes a Z-axis kinematics and a swivel arm, and furthermore comprises a plurality of hydraulic actuators, in particular at least one tilting hydraulic piston and at least one lifting hydraulic piston, as well as a control device of the type described above. In this way, the driven device can exhibit the same advantages and properties as described above, at least by analogy. Furthermore, the driven device can also be adapted in the manner described above, at least by analogy.

[0032] Furthermore, a work vehicle is proposed which has a hydraulic device of the type described above. In this way, the resulting work vehicle can have the same properties and advantages, at least by analogy. Likewise, the work vehicle can also be adapted in the manner described above, at least by analogy.

[0033] Further advantages, features and functions of the invention will become apparent from the following detailed description of the invention in conjunction with the accompanying drawings, the drawings of which show the following: Fig. 1: an embodiment of a kinematic system for a wheel loader in a first position; Fig. 2: an exemplary embodiment of a kinematic system for a wheel loader according to Fig. 1 in a second position; Fig. 3: the kinematics of a wheel loader according to Fig. 1 in a third position; Fig. 4: a flowchart illustrating a possible method for controlling a hydraulic kinematic system; Fig. 5: Different definitions of parts, angles, lines, and connections in kinematics according to the Fig. 1 to 3.

[0034] Fig. Figure 1 shows a kinematics 1 for a wheel loader (not shown) in a first position, featuring a Z-kinematics 2. In the Fig. In the position shown, the kinematics 1 are shown in a lowered position of the swivel arm 3 with a horizontal orientation of the fork 4.

[0035] As is generally known in the prior art, the kinematics 1 has a pivot arm 3 which is pivotably connected at the hinge point O to the mounting base 5 of the kinematics 1 (see Fig. 5) The mounting base 5 is designed in such a way that it can be connected to a vehicle body (not shown) by means of a hinge 6 having a vertical axis. In this way, the kinematics 1 can be rotated parallel to the ground within a certain range.

[0036] The swivel arm 3 can be raised and lowered by means of a hydraulic piston 7. The hydraulic piston 7 is pivotally connected to the mounting base 5 at point B at one of its end sections (see figure). Fig. 5) With its other end area, the lifting hydraulic piston 7 is pivotably connected to the swivel arm 3 at point C.

[0037] Furthermore, a Z-kinematic mechanism 2 is provided on the swivel arm 3, which has a rotary lever 8. The rotary lever 8 is rotatably attached to the swivel arm 3 at point F. As can easily be seen from the figures, point F is located in a central region of the rotary lever 8, with the position of point F being offset from the exact center, in this case in the direction of point H.

[0038] Furthermore, the rotary lever 8 is rotatably connected at point G to a connecting lever 9. Point G is located – as can easily be seen in the figures – at one of the end regions of the connecting lever 9, while the other end region of the connecting lever 9 is rotatably connected at point J to a tool mounting 10. The tool mounting 10 can be used to detachably attach a tool, such as a fork 4, a shovel, an excavator bucket, and the like.

[0039] The Z-kinematics 2 can be driven by the tilting hydraulic piston 11. The tilting hydraulic piston 11 is connected at one end of its end at point H to one end of the rotary lever 8, whereas at its other end it is connected at point A to the mounting base 5.

[0040] Furthermore, the tool holder 10 is pivotably connected to the swivel arm 3 at point E.

[0041] As is known from the prior art, the swivel arm 3 can be raised or lowered by driving the lifting hydraulic piston 7, while the tool holder 10 (and accordingly the tool attached to it, such as a fork 4) can be tilted by corresponding expansion or contraction of the tilting hydraulic piston 11.

[0042] When the kinematics 1 moves from its lowered position, as seen in Fig. 1 is shown, in a raised position, as shown in Fig. As shown in Figure 2, the fork 4 is to be moved. This movement can be carried out by an expanding movement of the lifting hydraulic piston 7. Based on the basic structure of the kinematics 1, this causes a certain problem. Specifically, the lifting movement caused by the lifting hydraulic piston 7 leads to a change in the orientation of the fork 4. In this case, the upward movement causes the fork 4 to tilt downwards, so that the kinematics 1 ultimately change in the Fig. 2 will be located in the position shown.

[0043] To avoid this effect, which can cause goods (not shown) located on the fork 4 to fall off when the fork 4 is raised, a corrective control is applied to the tilting hydraulic piston 11, as described in the present disclosure. This correction is applied automatically by an (electronic) controller (for example, a programmable single-board controller) when the operator commands raising or lowering. Accordingly, in addition to a simple control of the lifting hydraulic piston 7, the controller will also command a suitable control of the tilting hydraulic piston 11. In this way, raising with the correction applied results in the end position as described in the Fig. Figure 3 shows that the fork 4 remains in a horizontal position, although the operator only manually commands an expansion of the lifting hydraulic piston 7.

[0044] In order for the controller to calculate a suitable correction signal, the controller requires, in addition to the control command applied by the operator, information regarding the current position of kinematics 1.

[0045] In the embodiment shown here, two angle detectors are used for this purpose. The two sensors (not shown) are positioned at point F and point O, respectively. They are used to measure the angle α (which corresponds to the angle between lines OA and OF) and the angle β (which corresponds to the angle between lines AF and HF).

[0046] It should be noted that this is only one possible embodiment. Angle detectors at other positions and / or position detectors, in particular for measuring the positions of the hydraulic pistons 7, 11 or the like, can be used (partially) additionally and / or (partially) alternatively.

[0047] Fig. Figure 4 shows an elementary flowchart 19 of the procedure to be carried out. A controller checks 20 whether there is an input from the operator. If an input is detected, the controller checks the type of command. If a movement of the tilting hydraulic piston 11 is commanded, the algorithm 22 jumps directly to step 30, where the command is applied to the appropriate actuators, in this case to the tilting hydraulic piston 11.

[0048] However, if a raise or lower command is applied, the algorithm jumps to step 23, where sensor data from the angle / position sensors is read in.

[0049] Using the position data and the input control signal (control of the lifting hydraulic piston 7), a correction command 24 is calculated (in this case for the tilting hydraulic piston 11). Both commands, i.e., the input control signal and the correction command, are passed on to step 30 and applied to the respective hydraulic pistons 7 and 11.

[0050] The algorithm then jumps back to 31 and is executed again.

[0051] The mathematical model used in step 24 of flowchart 19 to calculate the correction signal is derived using the following equations, which refer to the in Fig.The notation shown in Figure 5 is explained in more detail below. Furthermore, the notation BC is used to denote a line between points B and C (and correspondingly for other points). The law of cosines for general triangles (non-right-angled triangles) is also used regularly below. As is readily apparent to a person skilled in the art, some distances are fixed by the mechanical design of the driven device, while others change. In particular, the lengths of the hydraulic pistons 7 and 11 change. It should be noted that in the embodiment described here, the angles α and β are measured using angle sensors. Naturally, the method can be easily adapted if different sensors are used.

[0052] We have the identity β = β' + β'', where β is measured and β'=cos−1(|AF|2+|OF|2−|AO|22⋅|AF|⋅|OF|) applies.

[0053] Using θ5=cos−1(|FC|2+|EF|2−|CE|22⋅|FC|⋅|EF|)−θ6, and assuming that points H, F and G are arranged along a straight line, one can use the relationship θ6 = π - (θ7 + β) and obtain: θ7=cos−1(|FC|2+|FO|2−|OC|22⋅|FC|⋅|FO|)−β''.

[0054] Knowing these angles, |GE| can be calculated: |GE|=|EF|2+|FG|2−2⋅|EF|⋅|FG|⋅cos(θ5).

[0055] Since all side lengths are known in triangle ΔFGE, the remaining angles in the triangle can be calculated. θ1+θ2=cos−1(|GE|2+|FG|2−|FE|22⋅|GE|⋅|FG|), θ8+θ4=cos−1(|JE|2+|GE|2−|JG|22⋅|JE|⋅|GE|), θ1=cos−1(|JG|2+|GE|2−|JE|22⋅|JG|⋅|GE|).

[0056] Thus, θ2 can be determined. In the following, we must consider two different cases, since triangle ΔFJE rotates at a specific point. Therefore, |OJ| must be calculated by distinguishing between two cases: for β≤49.505:θ2=cos−1(|GE|2+|FG|2−|FE|22⋅|GE|⋅|FG|)+θ1 and for β>49.505:θ2=cos−1(|GE|2+|FG|2−|FE|22⋅|GE|⋅|FG|)−θ1.

[0057] This results in |FJ|=|JG|2+|FG|2−2⋅|JG|⋅|FG|⋅cos(θ2).

[0058] If you know |FJ| you can θ 10 about the equation θ10=cos−1(|FJ|2+|FE|2−|JE|22⋅|FJ|⋅|EF|) calculate.

[0059] Due to the fact that triangle ΔFJG rotates at a certain point, two cases must be considered to calculate |OJ|: for β≥95: |OJ|=|OF|2+|FJ|2−2⋅|OF|⋅|FJ|⋅cos(β'+θ7+θ6+θ5−θ10), and for β>95: |OJ|=|OF|2+|FJ|2−2⋅|OF|⋅|FJ|⋅cos(β'+θ7+θ6+θ5+θ10).

[0060] Therefore, it is possible to calculate all angles within triangle AOEJ as follows: ϕ1=cos−1(|JE|2+|OE|2−|OJ|22⋅|JE|⋅|OE|) ϕ2=cos−1(|OJ|2+|JE|2−|OE|22⋅|OJ|⋅|JE|) ϕ3=cos−1(|OJ|2+|OE|2−|JE|22⋅|OJ|⋅|OE|). Reference list 1 Kinematics 2 Z-kinematics 3 swivel arms 4 Forks 5 Mounting base 6 hinge 7-stroke hydraulic pistons 8 rotary levers 9 connecting levers 10 Tool fastening 11 tilting hydraulic pistons 19 Flowchart 20 Check for user input 21 Check command type 22 Jump to 30 23 Reading in sensor data 24 Calculation of correction command 30 Application Command 31 Return

Claims

[1] Method (19) for controlling a hydraulic device (1) with a mounting base (5), a pivoting arm (3) arranged pivotably on the mounting base (5), a Z-kinematics (2) arranged on the pivoting arm (3) which is designed and configured to tilt a tool mounting device (10), wherein the tool mounting device (10) is pivotably attached to the pivoting arm (3), wherein the pivot arm (3) is moved by means of at least one lifting hydraulic piston (7), wherein the lifting hydraulic piston (7) is connected to the pivot arm (3) and the mounting base (5), and wherein the Z-kinematics (2) is moved by means of at least one tilting hydraulic piston (11), wherein the tilting hydraulic piston (11) is connected to a lever of the Z-kinematics (2) and the mounting base (5), wherein, after input of an input control signal to change the position of the lifting hydraulic piston (7), a compensation signal is automatically generated and applied to the tilting hydraulic piston (11) to substantially maintain the orientation of the tool mounting device (10), wherein the compensation command is automatically generated by a control device by outputting a suitable control command to the tilting hydraulic piston (11) using a mathematical model of the hydraulic device (1) based on the input control signal for the lifting hydraulic piston (7), and the control device thereby performs a suitable rotational compensation, where the compensation command can be individually selected to be limited or increased by a percentage. [2] Method (19) according to claim 1, characterized by, that the Z-kinematics (2) has a rotary lever (8) and a connecting lever (9), wherein the rotary lever (8) is pivotably mounted on the pivot arm (3) with its central region; is pivotably connected to the tilting hydraulic piston (11) with a first of its end regions; and is pivotably connected to the connecting lever (9) with a second of its end regions; and wherein the connecting lever (9) is connected to the rotary lever (8) at a first of its end regions, and to the tool fastening device (10) with a second of its end regions. [3] Method (19) according to claim 2, characterized by, that the method is applied to a hydraulic device (1), in particular to a hydraulic device (1) having a Z-kinematics (2) which is operated on different sides of one of its dead center positions, preferably across its dead center position, wherein at the dead center position a movement of the hinge point between the rotary lever (8) and the connecting lever (9) in a certain transaction direction, a stopping with respect to this direction and a reversal of the direction of movement in this direction takes place when a rotational movement of the rotary lever (8) is carried out. [4] Method (19) according to any of the preceding claims, characterized by, that a shovel, a fork (4), an excavator bucket and / or a grabber can be attached to the tool attachment device (10) and / or by the fact that the hydraulic device (1) forms part of a shovel loader, a wheel loader, a telescopic wheel loader, a telehandler, a backhoe excavator, an excavator and / or a forklift. [5] Method (19) according to any of the preceding claims, characterized by that the hydraulic device (1) is mounted on a vehicle and / or characterized by that the mounting base is a vehicle body and / or characterized by that the mounting base is preferably permanently attached to the vehicle body. [6] Method (19) according to any of the preceding claims, characterized by that the input control signal is provided by a human operator. [7] Method (19) according to any of the preceding claims, characterized bythat the control commands are influenced by at least one sensor signal, in particular by a position sensor signal and / or an angle sensor signal. [8] Method (19) according to any of the preceding claims, characterized by , that the method determines the angle ϕ1 between the line OE connecting points O and E and the line EJ connecting points E and J using the formula ϕ1=cos−1(|JE|2+|OE|2−|OJ|22⋅|JE|⋅|OE|) calculated where O is the hinge point between the swivel arm (3) and the mounting base (5), E is the hinge point between the swivel arm (3) and the tool mounting device (10), and J is the hinge point between the connecting lever (9) of the Z-kinematics (2) and the tool mounting device (10). [9] Method (19) according to any of the preceding claims, characterized by, that the method determines the angle ϕ2 between the line OJ connecting points O and J and the line EJ connecting points E and J, using the formula ϕ2=cos−1(|OJ|2+|JE|2−|OE|22⋅|OJ|⋅|JE|) calculated where O is the hinge point between the swivel arm (3) and the mounting base (5), E is the hinge point between the swivel arm (3) and the tool mounting device (10), and J is the hinge point between the connecting lever (9) of the Z-kinematics (2) and the tool mounting device (10). [10] Method (19) according to any of the preceding claims, characterized by , that the method determines the angle ϕ3 between the line OJ connecting points O and J and the line OE connecting points O and E, using the formula ϕ3=cos−1(|OJ|2+|OE|2−|JE|22⋅|OJ|⋅|OE|) calculated where O is the hinge point between the swivel arm (3) and the mounting base (5), E is the hinge point between the swivel arm (3) and the tool mounting device (10), and J is the hinge point between the connecting lever (9) of the Z-kinematics (2) and the tool mounting device (10). [11] Method (19) according to any of the preceding claims, characterized by , that the compensation order is limited in its scope. [12] Control device, in particular electronic control device, which is designed and configured to perform a method according to one of the preceding claims. [13] Hydraulic device (1) comprising a Z-kinematics (2) and a swivel arm (3), further comprising a plurality of hydraulic actuators (7, 11), in particular at least one tilting hydraulic piston (11) and at least one lifting hydraulic piston (7), and a control device according to claim 12. [14] Work vehicle comprising a hydraulic device (1) according to claim 13.

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