JP2023508928A - Method for controlling hydraulic cylinders of working machines - Google Patents

Abstract

A method (100) for controlling a hydraulic cylinder of a working machine, in particular a mobile working machine, is proposed, comprising the steps of receiving by a control unit (1) a motion parameter target value (11) of the hydraulic cylinder; using a data-based model (10), in particular an artificial neural network (10), and , determined by the control unit (1), taking into account preset and/or presettable tolerances for the valve parameter target values (29) and the hydraulic cylinders of the working machine, in particular of a mobile working machine. and controlling the valve unit associated with the hydraulic cylinder by means of the control unit (1) in dependence on the determined valve parameter target value (29), in order to control the .

Description

The invention relates to a method of controlling a hydraulic cylinder of a working machine and a method of controlling an attachment of a working machine, according to the preamble of the independent claim. Objects of protection of the present invention are also the control unit controlling the hydraulic cylinders of the working machine and the control unit controlling the attachment of the working machine, as well as the working machine and the computer program.

Modern work machines are increasingly using automated or semi-automated work processes. The content of the function is currently often to follow a desired trajectory with respect to the Tool Center Point (TCP), or to guide the driver in following the desired trajectory in the case of an assist function. It is to support.

DISCLOSURE OF THE INVENTION The object of the present invention is a method for controlling hydraulic cylinders of working machines, in particular mobile working machines.

The method includes receiving, by a control unit, a motion parameter target value for a hydraulic cylinder. The method further comprises determining, by the control unit, valve parameter target values for the valve unit associated with the hydraulic cylinder in dependence on the received motion parameter target values. Here, the valve parameter target values are determined using data-based models, in particular artificial neural networks, and taking into account predetermined and/or predefinable tolerances for the valve parameter target values. The method further comprises controlling, by the control unit, a valve unit associated with the hydraulic cylinder in dependence on the determined valve parameter target value for the purpose of controlling the hydraulic cylinder of the mobile work machine. .

The object of protection of the present invention is also a control unit for controlling hydraulic cylinders of a working machine, in particular a mobile working machine, the control unit being arranged to perform or control the steps of the aforementioned method for controlling a hydraulic cylinder. It is

The object of protection of the present invention is also a method for controlling attachments of working machines, in particular mobile working machines. Here, the attachment is movable relative to the working machine by a hydraulic cylinder.

The method includes receiving by a control unit an attachment target position. The method further includes determining, by the control unit, a motion parameter target value for the hydraulic cylinder in dependence on the received attachment target position. Moreover, the method includes determining, by the control unit, a valve parameter setpoint value for the valve associated with the hydraulic cylinder in dependence on the received kinematic parameter setpoint value. The valve parameter target values are determined using data-based models, in particular artificial neural networks, and taking into account preset and/or presettable tolerances for the valve parameter target values. The method further comprises controlling, by the control unit, a valve unit associated with the hydraulic cylinder in dependence on the determined valve parameter target value for the purpose of controlling the attachment of the mobile work machine by the hydraulic cylinder. including.

The object of protection of the invention is additionally a control unit for controlling an attachment of a working machine, in particular a mobile working machine, which control unit performs or controls the steps of the aforementioned method for controlling the attachment. It is configured.

The object of protection of the invention is also a working machine, in particular a mobile working machine, with an attachment, at least one hydraulic cylinder for the movement of this attachment and the aforementioned control unit for controlling the attachment.

A subject of protection of the present invention is also a computer program adapted to implement and/or control one or both of the aforementioned methods of controlling hydraulic cylinders and/or of the aforementioned methods of controlling attachments.

The work machine may be a stationary work machine or, preferably, a mobile work machine. The work machine can be a work machine for construction, agriculture, forestry or logistics applications. The mobile work machine can be, for example, an excavator, wheel loader, industrial truck or aerial work platform. The stationary work machine can be, for example, a hydraulically driven industrial robot.

A work machine attachment may be an attachment for working and/or treating ground and/or an attachment for transporting loads in the agricultural and/or forestry and/or building industries. The attachment can be, for example, a shovel, shovel or working cage. The attachment can be located on the work arm, lift frame or lift platform of the work machine.

A hydraulic or hydraulic cylinder is configured to create relative motion between the attachment and the work machine. To this end, a hydraulic cylinder may include a housing and a piston. The piston is movable relative to the housing, in particular movable into and out of the housing, by the application of pressure of a hydraulic liquid, preferably hydraulic oil.

A valve unit associated with the hydraulic cylinder is configured to apply pressure to the hydraulic fluid in a defined manner. That is, the valve unit associated with the hydraulic cylinder is configured to generate relative movement between the piston and housing of the hydraulic cylinder.

A valve unit may include one or more valves. The valve can be configured as a magnetic valve or as a pneumatically actuable or pneumatic valve. The valve unit may comprise, in particular, an electromagnetic pilot valve and a main valve, preferably associated with this pilot valve, in particular pneumatically operable.

By controlling the valve unit it is possible to control the relative movement between the piston and the housing of the hydraulic cylinder. This relative movement can generate relative movement between the attachment and the working machine, in particular between the attachment and the working arm and/or lifting frame of the working machine, based on the arrangement of the hydraulic cylinders in the attachment. .

Control, in the context of the present invention, can be understood as control in the sense of producing an output quantity based on an input quantity. Control also preferably includes closed-loop control in the sense of continuously determining the actual value of the quantity to be closed-loop controlled and continuously comparing this actual value with the desired value of the quantity to be closed-loop controlled. It can be understood that

The attachment target position can be the spatial relative position of the attachment relative to the work machine containing the attachment, or the spatial position in an external reference coordinate system, e.g. It can be a spatial position in a reference coordinate system. The attachment target position is preferably the spatial position of the attachment's Tool Center Point (TCP). The target position of the attachment can, for example, be preset for one work step of one work process to be carried out by the work machine.

Determining the motion parameter target values in dependence on the attachment target position can be performed by software-based trajectory planning for the attachment or work machine. Determining the motion parameter target value may be performed while considering at least a portion of the kinematics of the work machine.

A motion parameter of a hydraulic cylinder is one parameter of motion of the hydraulic cylinder. The movement of the hydraulic cylinder is preferably relative movement between the piston of the hydraulic cylinder and the housing. The movement of the hydraulic cylinder can be uniform or preferably uniform acceleration.

The motion parameter of the hydraulic cylinder can be velocity or acceleration. Preferably, the motion parameter is the relative velocity or relative acceleration between the piston and housing of the hydraulic cylinder.

A motion parameter target value is one value of a motion parameter, or a change in the value of the motion parameter over time, according to which the movement of the hydraulic cylinder should be performed.

A valve parameter of a valve unit may be a parameter of one or more valves of the valve unit. The valve parameter can be the valve energization or current strength of the magnet valve. The valve parameter can also be the pressure that operates a pneumatically operable valve. The valve parameter can also be the valve throttle opening area of the valves of the valve unit.

A data-based model, in the context of the present invention, can be understood to be a mathematical model or a mathematical algorithm, which, given previously as input variables the values of the motion parameters, outputs It is configured to obtain the value of the valve parameter as the strength. That is, in other words, the data-based model associates or correlates one value of the motion parameter with one value of the valve parameter, or interlinks the value of the motion parameter and the value of the valve parameter. The determined value of the valve parameter depends in particular on the value of one or more other parameters of the hydraulic cylinder and/or on the unit interacting with the hydraulic cylinder.

Data-based models are based on learning or training data sets. These training data sets comprise combinations of values of motion parameters and valve parameters, and preferably one or more other parameters, eg value tuples. The training data set may be determined during operation of the hydraulic cylinders, eg, during operation of a work machine including the hydraulic cylinders. The training data set corresponds to combinations of values that occur or exist during operation of the hydraulic cylinders.

The data-based model is configured to output a value of the valve parameter for each arbitrary value of the motion parameter technically achievable by the hydraulic cylinder, based on the training data set, e.g., by using a regression process. ing. That is, in other words, the data-based model is configured to combine or correlate, or machine learn, even for combinations of values that are not included in the training data set. Preferably, the data-based model is not a priori provided with a physical-technical model of the hydraulic cylinder. Or, in other words, a data-based model is a model that is generated using machine learning methods.

The goodness or quality of performance of the data-based model is determined by the predetermined motion parameter targets when controlling the valve unit associated with the hydraulic cylinder using the valve parameter targets determined by the data-based model. value and the actual value of the motion parameter. For the hydraulic cylinder operating range for which the training data set is representative, i.e. for which the training data set contains a sufficient number of relevant value combinations, the actual values of the kinematic parameters and the preliminary Small deviations from the stated target values can be expected.

For hydraulic cylinder operating ranges for which the training data set is not representative, i.e. for which the training data set does not contain a sufficient number of relevant value combinations, the actual values of the motion parameters and Large deviations from the predetermined target value can occur.

The data-based model is preferably configured as an artificial neural network.

The allowable range of the valve parameter represents the value range of the valve parameter that is allowed or permitted for the control of the valve unit. Advantageously, the tolerance range for the valve parameter target value is a subrange of a technically realizable or conceivable value range for the valve parameter. For example, a technically possible value range for a valve parameter may be a current strength range that includes a current strength greater than or equal to a first minimum current strength and less than or equal to a first current strength maximum for valve energization. The acceptable range may be a current strength range including a current strength greater than or equal to a second minimum current strength and less than or equal to a second current strength maximum for valve energization, where the second minimum is the second current strength. greater than or equal to a minimum value of 1, the second maximum value being less than or equal to the first maximum value, excluding both maximum values and both minimum values being equal. This configuration makes it possible to restrict the valve parameter setpoint values to a subset of the technically possible value range, thereby ensuring a reliable operating state of the hydraulic cylinders, in particular of the working machine.

The method and corresponding control unit increase safety and reliability in automated control of hydraulic cylinders or attachments movable by hydraulic cylinders. By using data-based models, the method can also be used for working machines with complex hydraulic properties that can only be physically and technically modeled in sufficient detail with great effort. . Taking into account the tolerance ranges when determining the desired valve parameter values ensures that the hydraulic cylinders or attachments are always driven within a safe value range, ie even in rare operating states. This can enhance the safety of data-based closed-loop control strategies for partially or fully automated work machines.

Determining the valve parameter target value includes determining a valve parameter provisional target value, and depending on this provisional target value, the valve parameter target value is preset with respect to the valve parameter target value. and/or within presettable tolerances. Preferably, in a first step the provisional valve parameter target values are determined and then in a second step the valve parameter target values are determined.

A valve parameter interim target value can be a value of a valve parameter that is within or outside of an acceptable range for the valve parameter target value. Preferably, the valve parameter target value matches the valve parameter provisional target value when the valve parameter provisional target value is within the acceptable range.

When the valve parameter interim target values are out of the acceptable range, the valve parameter interim target values can be changed or matched or corrected when the target values are determined. It is conceivable here that the determined setpoint value corresponds to the tolerance value of the valve parameter, which has the shortest distance to the provisional setpoint value with respect to the received or predetermined setpoint value of the kinematic parameter. is.

With this arrangement, provisional setpoint values outside the permissible range are not used for the control of the valve unit, whereby dangerous operating states can be avoided.

It is likewise advantageous for the tolerance range to represent the permitted value range for the valve parameter, the permitted value range, in particular the size of the permitted value range, depending on the value of the motion parameter. The size or width of the permitted value range can be the same for all values of the motion parameter or, preferably, different sizes. The size of the value range for a valve parameter can be the width of the value range. The assumption here is that the size of the value range represents the difference between the maximum value of the value range and the minimum value of the value range.

It is advantageous if the permitted value range, in particular the size of the permitted value range, additionally depends on the actual values of the hydraulic cylinders and/or other parameters of the working machine. Other parameters may correspond to time derivatives of motion parameters. Another parameter may be pressure, for example the pressure of hydraulic fluid in a hydraulic cylinder. Another parameter could be the temperature of the hydraulic fluid in the hydraulic cylinder. Furthermore, it is conceivable that another parameter is the number of revolutions of the motor of the work machine.

The actual values of the other parameters are defined values of the motion parameters and/or defined values of the valve parameters and/or at least one other definition of the other parameters considered by the data-based model. It is conceivable to represent multiple training data sets for the values obtained. For example, the tolerance size for a value of a motion parameter with a large number of training data sets should be larger than that for a value of a motion parameter with a smaller number of training data sets. can be done.

This arrangement allows the tolerances to be matched depending on the goodness or quality of performance of the data-based models for the various motion parameters, thereby ensuring safe operation of the hydraulic cylinder or work machine. Efficiency of control is enhanced.

The method includes determining a tolerance range for the valve parameter target value, the tolerance range being determined by the frequency of exceeding a preset and/or presettable threshold during operation of the hydraulic cylinder. It is even more advantageous if the value is included. For this purpose, the values of valve parameters and motion parameters and the frequency of occurrence of these values can be determined during operation of the hydraulic cylinder. The threshold can be determined absolutely or relative to an average or maximum frequency of occurrence of the value of the valve parameter. Preferably, the threshold increases as the value of the motion parameter increases. Thereby, the width of the tolerance range becomes smaller for safety reasons at higher values of the motion parameter.

During operation of the hydraulic cylinder, for each value of the valve parameter, a corresponding value of at least one of the motion parameters occurs with increased probability. For each value of the valve parameter, the value of the individual motion parameter having the highest frequency of value occurrence during hydraulic cylinder operation may represent the ideal or dominant value of the motion parameter. The ideal or dominant value of the motion parameter may correspond to the value of the motion parameter in a steady state of the hydraulic cylinder or in a state of the hydraulic cylinder in which no change in the value of the motion parameter over time occurs. In transition states of the hydraulic cylinder, where changes in the values of the motion parameters over time can occur, values of the motion parameters that differ from the ideal values of the motion parameters can also occur with a correspondingly reduced frequency of occurrence. There is

This arrangement allows the tolerances to be determined in a particularly simple way before carrying out the method. Furthermore, this also makes the control of the hydraulic cylinders and work machine robust against sensor failures, because the tolerances are based on values determined prior to implementation of the method or determined off-line. , and does not depend on the measurement signals detected during the execution of the method.

Moreover, it is advantageous if the valve parameter setpoint value is additionally determined as a function of at least one other parameter of the hydraulic cylinder and/or of the work machine, in particular its value. The other parameter is preferably a parameter different from the motion parameter. Other parameters can also correspond to time derivatives of motion parameters. Another parameter may be pressure, for example the pressure of hydraulic fluid in a hydraulic cylinder. Another parameter is preferably the pressure difference between the pressure on the piston side of the hydraulic cylinder and the pressure on the rod side of the hydraulic cylinder. Alternatively or additionally, the other parameter is the LS pressure (load sensing pressure) of the load sensing system associated with the hydraulic cylinder and the pressure supplied from the pump unit for pressurizing the hydraulic fluid. is the difference between

Another parameter could be the temperature of the hydraulic fluid in the hydraulic cylinder. Furthermore, it is conceivable that another parameter is the number of revolutions of the motor of the work machine.

The one or more other parameters are preferably included in the combination of values of the training data set on which the data-based model is based. Or, in other words, the data-based model preferably maps the value of one valve parameter to a combination of values of motion parameters and values of other parameters. This arrangement allows valve parameter target values to be determined with improved accuracy even in transitional operating regions where changes in the values of the kinematic parameters occur over time.

Furthermore, if the step of determining the valve parameter target value includes determining a target position of an operating member, particularly a joystick, of the work machine, wherein the valve parameter target value is determined using the determined target position of the operating member, Advantageous. The target position of the operating member is determined using a data-based model, in particular an artificial neural network, and taking into account preset and/or predefinable tolerances for valve parameter target values, receiving motion parameters. determined depending on the set target value.

The operating member is used as means for controlling the movement of the hydraulic cylinder. The target position of the operating member of the work machine can be the target position or target state of the operating member. In order to operate the hydraulic cylinder, the valve unit associated with the hydraulic cylinder is controlled depending on the position or state of the operating member. For this purpose, each position of the operating member is assigned a control signal for controlling the valve unit or a state of the valve unit.

With this arrangement, the motion parameter target values can initially be assigned target positions of the operating members, whereby the control of the valve unit is based on the software and hardware already provided on the working machine, of the operating members. It can be done depending on the position.

A computer program product or computer program with program code is also advantageous, which program code can be stored on a machine-readable carrier or a machine-readable storage medium, such as a semiconductor memory, a hard disk storage device or an optical storage device; This program code can be used to perform, implement and/or control the steps of the method according to one of the previously described embodiments when the product or program is run on a computer or device. .

The invention will now be described by way of example with reference to the accompanying drawings.

Fig. 4 schematically shows a control unit controlling hydraulic cylinders; FIG. 4 is a diagram schematically showing how an attachment of a work machine is controlled based on data in a closed loop; FIG. 5 is a diagram showing the frequency of positions of the operating member of the excavator depending on the target velocity of the hydraulic cylinder of the excavator; 4 is a flow chart illustrating a method of controlling hydraulic cylinders of a mobile work machine;

FIG. 1 schematically shows a control unit 1 for controlling hydraulic cylinders of a working machine, for example an excavator.

The control unit 1 comprises a data-based model 10 configured as an artificial neural network 10 , a storage unit 20 , a limiting unit 26 and a calculation unit 30 . The control unit 1 is configured to determine a setpoint position 27 or a setpoint position value 27 of an operating member controlling an excavator attachment in response to a kinematic parameter setpoint value 11 formed as a relative velocity 11 of the hydraulic cylinder. . The control unit 1 is further arranged to determine valve parameter target values 29 of the valve units associated with the hydraulic cylinders on the basis of the operating member target positions 27, whereby the determined valve parameter target values 29 to control the valve unit associated with the hydraulic cylinder controls the hydraulic cylinder.

An artificial neural network 10 is arranged to receive a relative velocity target value 11 of a hydraulic cylinder. Furthermore, the artificial neural network 10 is arranged to receive the actual values of the pressure differences 13,15. The pressure difference 13 is preferably the pressure difference between the pressure on the piston side of the hydraulic cylinder and the pressure on the rod side of the hydraulic cylinder. The pressure difference 15 is the difference between the LS pressure (load sensing pressure) of the load sensing system associated with the hydraulic cylinder and the pressure supplied from the pump unit to apply pressure to the hydraulic fluid.

Moreover, the artificial neural network 10 is configured to determine a provisional target position value 21 of the operating member on the basis of the received values 11, 13, 15. FIG. In addition to this, the artificial neural network 10 has a coefficient 23 such that: 1 configured to output one or more values. In operating regions with a large training data set, this coefficient is higher in the data-based model than in operating regions with a smaller training data set, since the quality of the data-based model is higher. Therefore, it can take larger values.

The memory unit 20 contains at least one characteristic curve with the relative velocity 11 and the ideal or prevailing position 25 of the operating member, see FIG. The memory unit 20 is arranged to output the value of the ideal or preferred position 25 of the operating member in response to the relative velocity setpoint value 11 of the hydraulic cylinder.

The limiting unit 26 is arranged to output a target position value 27 of the operating member in response to the provisional target position value 21 of the operating member, the ideal position 25 of the operating member and the factor 23 . For this purpose, the limiting unit 26 is arranged to determine the width of the tolerance range for the target position 27 of the operating member on the basis of the value of the ideal position 25 of the operating member and the factor 23 . This tolerance extends from ideal position 25 values decreased by a factor of 23 to ideal position 25 values increased by a factor of 23 .

Moreover, the limiting unit 26 is configured to take this tolerance into account when determining the desired position value 27 of the operating member. For this purpose, the limiting unit is configured to determine whether the provisional desired position value 21 of the operating member lies within or outside the determined tolerance range. If the temporary target position value 21 of the operating member is within the allowable range, the value of the target position 27 matches the temporary target position value 21 . If the provisional setpoint position value 21 of the operating member is outside the permissible range, the setpoint value 27 of the position of the operating member corresponds to the value of the permissible range which has the smallest distance to the provisional setpoint position value 21 of the hydraulic cylinder.

In response to the determined position setpoint values 27 of the operating member, the calculation unit 30 determines valve parameter setpoint values 29 of the valve unit associated with the hydraulic cylinder for the purpose of controlling the hydraulic cylinder of the mobile working machine. , to control the valve unit as a function of the determined valve parameter desired value 29 .

FIG. 2 shows schematically how the closed-loop control unit 2 is used for the data-based closed-loop control of a working machine, in particular an attachment of a shovel. This closed-loop control includes model-based velocity closed-loop control of the hydraulic cylinders of the mobile work machine, similar to FIG. The hydraulic cylinder is configured to generate movement of an attachment located on a working arm of the work machine, in which the joint angle between the joints of the working arm of the work machine is varied.

The closed-loop control unit 2 includes an attitude controller 32 (“pose controller”), an inverse kinematics 34 (“inverse kinematics”), a velocity controller 36 (“velocity controller”), a controlled system 38, a forward kinematics 40 (“direct kinematics ”), one or more sensors 42 (“sensors”), and a model based filter 44 (“model based filter”).

The attitude controller 32 calculates the difference between the tool center point (TCP) target coordinates 31 of the attachment on the work machine generated by the calculation unit 30 for trajectory generation (“trajectory generator”) and the received TCP actual coordinates 41 . In response, it is arranged to determine the TCP target rate 33 .

Inverse kinematics 34 is configured to determine a joint angular velocity target 35 or a work machine hydraulic cylinder velocity target 35 in response to the determined TCP velocity target 33 .

The speed controller 36 is configured to determine the adjustment amount target value 37 in response to the determined joint angular velocity target value 35 or in response to the determined hydraulic cylinder speed target value 35 .

To this end, the speed controller 36 includes an inverse behavior 36a (“inverse manipulator behavior”) and a feedback controller 36b (“Feedback Controller”) of the controlled system 38 .

The reversal behavior 36a of the controlled system 38 is formed as a data-based model 10', in this example as an artificial neural network 10', and responds to the determined velocity setpoint 35 and the received pressure difference 51. Then, the adjustment amount 37 is output. The pressure difference 51 is the pressure difference between the pressure on the piston side of the hydraulic cylinder and the pressure on the rod side of the hydraulic cylinder, and the LS pressure (load sensing pressure) of the load sensing system associated with the hydraulic cylinder and the pump unit to the pressure supplied for applying pressure to the hydraulic oil.

A feedback controller 36b responds to the determined target velocity 35 and the actual joint angular velocity 45 or the actual hydraulic cylinder velocity 45 based on the difference or deviation between the target 35 and the actual 45: It is configured to match the adjustment amount 37 .

The controlled system 38 responds to the determined adjustment variable setpoint value 37 and, as a result, produces an actual angle value 39 of the joint or a position or setting position actual value 39 of the hydraulic cylinder.

The controlled system 38 includes valve dynamics 38a (“valve dynamics”), valve geometry 38b (“valve geometry”), valve cross section 38c (“valve cross section”), and hydraulic cylinder 38d (“hydraulic cylinder”). include. Controlled system 38 represents a hydraulic cylinder located on the excavator, which is configured to control the attachment.

Based on the valve dynamic 38a of the valve associated with the hydraulic cylinder, the valve is controlled to the valve spool position 55 of the valve corresponding to the adjustment amount 37. FIG.

Due to the valve geometry 38b of the valve, the valve results in a metering orifice restriction cross-section 57 of the valve at the valve spool position 55 .

Due to the valve cross section 38c of the valve and the pressure difference 51, this metering orifice restriction cross section 57 results in an actual volumetric flow 59 of hydraulic oil in the valve.

The hydraulic cylinder 38d is configured to adjust the joint angle actual 39 or hydraulic cylinder position actual in response to the determined actual volumetric flow 59 of hydraulic fluid and the load force 53 acting on the hydraulic cylinder 38d. It is

Via forward kinematics 40 , TCP actual coordinates 41 are obtained from joint angle actual values 39 or hydraulic cylinder speed actual values 39 .

One or more sensors 42 are configured to detect these TCP actual coordinates 41 . Furthermore, these sensors are arranged to convert the detected actual coordinates into electronically processable signals 43 .

A model-based filter 44 analyzes the electronically processable signals 43 of the sensors 42 to provide TCP actual coordinates 41, joint angle actual values 39 or hydraulic cylinder position actual values 39, and joint angular velocity actual values 45 or It is arranged to determine the hydraulic cylinder speed actual value 45 . The model-based filter 44 also passes the determined TCP actual coordinates 41 to the attitude controller 32, the determined joint angle actual values 39 to the inverse kinematics 34, and the determined joint angular velocity actual values 45 to the velocity controller 32. 36.

For the closed-loop control described so far, the artificial neural network 10' is trained prior to closed-loop control implementation.

The artificial neural network 10' calculates the adjustment amount 37, the pressure difference 51 and the difference 61 between the joint angle actual value 39 and the joint angle 63 determined by the artificial neural network 10' or the position actual value 39 of the hydraulic cylinder. It is configured to perform machine learning in response to the difference between the hydraulic cylinder position actual value 63 determined by the artificial neural network 10'. That is, the artificial neural network 10' is configured to machine-learn so that the difference 61 is as small as possible, preferably zero.

FIG. 3 shows the frequency of positions of the actuating member of the excavator as a function of the setpoint velocity of the hydraulic cylinder of the excavator. This drawing is based on measurement data detected during excavator operation.

On the horizontal axis of FIG. 3, the position or setting position x of the operating member configured as a joystick is plotted. The relative velocity v of the hydraulic cylinder is plotted on the vertical axis of FIG.

The gray levels indicate the relative frequency with which the corresponding value combinations of setting position x and relative velocity v occur during excavator operation. The frequency of occurrence of value combinations increases from black to white or from dark to light in the case of FIG. That is, the brighter the point in FIG. 3 corresponding to the combination of values, the higher the frequency of the combination of values.

What is evident from FIG. 3 is that, corresponding to the markedly bright points, for each joystick setting position a dominant velocity occurs with a significantly higher probability of occurrence. This speed can also be regarded as the ideal speed. Centered around the dominant velocity and parallel to the velocity axis, a region or band can be identified that can be taken as a form of variation. This variation or this region does not exist in an ideal shovel. In the case of an ideal work machine, each joystick position can be uniquely associated with one speed, while the control of the corresponding pump of the work machine optimally compensates for the action of load forces.

The width of the region or band in this sense is a measure for the deviation of the excavator hydraulic system from ideal hydraulics. Preferably, the prevailing speed is also the speed that the hydraulic cylinder reaches in steady state, while also different speeds occur in transition regions, eg during pressure build-up/acceleration processes.

FIG. 4 shows a flowchart of a method for controlling hydraulic cylinders of a mobile work machine. This method is generally referenced 100 .

At step 110, hydraulic cylinder motion parameter target values are received by a mobile work machine control unit.

In step 120, valve parameter target values for the valve unit associated with the hydraulic cylinder are determined as a function of the received kinematic parameter target values. The valve parameter target values are determined by the control unit using data-based models, in particular artificial neural networks, and taking into account preset and/or predefinable tolerances for the valve parameter target values. .

In step 130, for the purpose of controlling the hydraulic cylinders of the mobile working machine, the valve units associated with the hydraulic cylinders are controlled by the control unit in dependence on the determined valve parameter target values.

If an embodiment includes "and/or" a combination of a first feature and a second feature, this means that, according to one embodiment, this embodiment , having both the first characteristic and the second characteristic, and according to other embodiments, only the first characteristic or only the second characteristic.

Claims (14)

A method (100) for controlling hydraulic cylinders of a work machine, particularly a mobile work machine, comprising:
receiving (110) by a control unit (1) a motion parameter target value (11) of said hydraulic cylinder;
a data-based model (10), in particular an artificial neural network (10), for determining valve parameter target values (29) of the valve unit associated with said hydraulic cylinder in dependence on said received motion parameter target values (11); and taking into account pre-set and/or pre-settable tolerances for the valve parameter target value (29), determining (120) by said control unit (1);
In order to control the hydraulic cylinders of the working machine, in particular of a mobile working machine, the valve units associated with the hydraulic cylinders are activated in dependence on the determined valve parameter setpoint values in the control unit (1 ) controlling (130) by
A method (100) comprising: The step of determining (120) said valve parameter target value (29) comprises determining a valve parameter provisional target value, wherein depending on said provisional target value, said valve parameter target value (29) is converted to a determined target value ( 27) is within a preset and/or presettable tolerance for said valve parameter target value (29);
The method (100) of claim 1. said tolerance range represents a permitted value range for said valve parameter, said permitted value range depending on the value of said motion parameter (11);
A method (100) according to claim 1 or 2. Said permitted value range also depends on the actual values of other parameters (13, 15), in particular said movement parameters and/or pressure and/or speed and /or depending on the actual value of the time derivative of temperature,
The method (100) of claim 3. determining said tolerance for said valve parameter target value (27), said tolerance determined by the frequency of exceeding a preset and/or presettable threshold during operation of said hydraulic cylinder; containing the values of the valve parameters,
The method (100) of any one of the preceding steps. said tolerance range for said valve parameter target value (29) is a subrange of a technically realizable value range for said valve parameter,
The method (100) of any one of the preceding steps. Said valve parameter target value (29) further depends on at least one other parameter (13, 15), in particular said motion parameter and/or pressure and/or rotation of said hydraulic cylinder and/or said work machine. depending on the number and/or the time derivative of the temperature,
The method (100) of any one of the preceding steps. A method of controlling an attachment of a work machine, particularly a mobile work machine, said attachment being movable relative to said work machine by means of a hydraulic cylinder, comprising:
receiving a target position of said attachment by a control unit (1);
determining by the control unit (1) a motion parameter target value (11) of the hydraulic cylinder in dependence on the received attachment target position;
a data-based model (10), in particular an artificial neural network (10), for determining valve parameter target values (29) of the valve unit associated with said hydraulic cylinder in dependence on said received motion parameter target values (11); and taking into account pre-set and/or pre-settable tolerances for the valve parameter target value (29), determining (120) by said control unit (1);
for controlling the attachment of the working machine, in particular of the mobile working machine, by controlling the hydraulic cylinder, the valve unit associated with the hydraulic cylinder is adjusted to the determined valve parameter target value (29). dependently controlling (130) by said control unit (1);
method including. Said step (120) of determining said valve parameter target value (29) comprises determining a target position (27) of an operating member, in particular a joystick, of said work machine, said valve parameter target value (29) using the determined target position (27) of the member;
9. The method of claim 8. A control unit (1) for controlling a working machine, in particular a hydraulic cylinder of a mobile working machine, said control unit (1) comprising:
receiving a motion parameter target value (11) for said hydraulic cylinder;
a data-based model (10), in particular an artificial neural network (10), for determining valve parameter target values (29) of the valve unit associated with said hydraulic cylinder in dependence on said received motion parameter target values (11); and taking into account pre-set and/or pre-settable tolerances for said valve parameter target value (29),
for controlling the hydraulic cylinder of the working machine, in particular of a mobile working machine, to control the valve unit associated with the hydraulic cylinder in dependence on the determined valve parameter target value (29). A control unit (1), comprising: A control unit (1) for controlling an attachment of a working machine, in particular a mobile working machine, said attachment being movable relative to said working machine by means of a hydraulic cylinder, wherein The control unit (1) is
receiving a target position for the attachment;
determining a motion parameter target value (11) of said hydraulic cylinder in dependence on said received attachment target position;
a data-based model (10), in particular an artificial neural network (10), for determining valve parameter target values (29) of the valve unit associated with said hydraulic cylinder in dependence on said received motion parameter target values (11); and taking into account pre-set and/or pre-settable tolerances for said valve parameter target value (29),
for controlling the attachment of the working machine, in particular of the mobile working machine, by controlling the hydraulic cylinder, the valve unit associated with the hydraulic cylinder is adjusted to the determined valve parameter target value (29). A control unit (1) configured to control dependently. A working machine, in particular a mobile working machine, comprising an attachment, at least one hydraulic cylinder for movement of said attachment and a control unit (1) according to claim 11 for controlling said attachment. A computer program adapted to implement and/or control the method (100) according to any one of claims 1 to 7 and/or the method according to claim 8 or 9. 14. A machine-readable storage medium having a computer program according to claim 13 stored thereon.

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