CN114787854A

CN114787854A - Method for controlling hydraulic cylinder of working machine

Info

Publication number: CN114787854A
Application number: CN202080088623.2A
Authority: CN
Inventors: N·施特克尔; S·本兹; O·德米尔
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2019-12-21
Filing date: 2020-12-16
Publication date: 2022-07-22
Also published as: WO2021122718A1; JP2023508928A; DE102019220501A1

Abstract

A method for controlling a hydraulic cylinder of a working machine, in particular a mobile working machine, is proposed, comprising the following steps: -receiving a nominal value of a movement parameter (11) of the hydraulic cylinder by means of a control unit (1); -determining a setpoint value of a valve parameter (29) assigned to a valve unit of the hydraulic cylinder by means of the control unit (1) from the received setpoint value of the kinetic parameter (11) using a data-based model (10), in particular an artificial neural network (10), and taking into account a predefined and/or predefinable tolerance range for the setpoint value of the valve parameter (29); and-controlling the valve units assigned to the hydraulic cylinders by means of the control unit (1) in accordance with the determined target values of the valve parameters (29) in order to control the hydraulic cylinders of the, in particular, mobile working machine.

Description

Method for controlling hydraulic cylinder of working machine

Technical Field

The present invention relates to a method for controlling a hydraulic cylinder of a working machine and a method for controlling an additional device of a working machine according to the preambles of the independent claims. The control unit for controlling the hydraulic cylinder of the working machine and the control unit for controlling the additional equipment of the working machine as well as the working machine and the computer program are also subjects of the present invention.

Background

Automated or partially automated work processes are increasingly used in modern work machines. Currently, the content of this functionality is often to follow a desired trajectory for the Tool Center Point (TCP), or in the case of an assistance function is often to support the driver to follow a desired trajectory.

Disclosure of Invention

The subject of the invention is a method for controlling a hydraulic cylinder of a working machine, in particular a mobile working machine.

The method comprises the following steps: a step of receiving, by means of a control unit, a nominal value of a movement parameter of the hydraulic cylinder. The method further comprises: a step of determining a setpoint value of a valve parameter of a valve unit assigned to the hydraulic cylinder by means of a control unit as a function of the received setpoint value of the movement parameter. In this case, the setpoint value of the valve parameter is determined using a data-based model, in particular an artificial neural network, and taking into account a predefined and/or predefinable tolerance range of the setpoint value of the valve parameter. The method further comprises: a step of controlling a valve unit assigned to the hydraulic cylinder by means of the control unit in accordance with the determined nominal value of the valve parameter in order to control the hydraulic cylinder of the mobile working machine.

The invention also relates to a control unit for controlling a hydraulic cylinder of a mobile work machine, wherein the control unit is designed to carry out or control the steps of the method for controlling a hydraulic cylinder.

The invention also relates to a method for controlling an additional device, in particular of a mobile working machine. In this case, the additional device can be moved relative to the working machine by means of a hydraulic cylinder.

The method comprises the following steps: a step of receiving the nominal position of the additional device by means of a control unit. The method further comprises: a step of determining a setpoint value of the movement parameter of the hydraulic cylinder from the received setpoint position of the additional device by means of the control unit. The method further comprises: a step of determining a setpoint value of a valve parameter of a valve unit assigned to the hydraulic cylinder by means of the control unit as a function of the received setpoint value of the movement parameter. In this case, the setpoint value of the valve parameter is determined using a data-based model, in particular an artificial neural network, and taking into account a predefined and/or predefined tolerance range for the setpoint value of the valve parameter. The method further comprises: a step of controlling a valve unit assigned to the hydraulic cylinder by means of the control unit in accordance with the determined nominal value of the valve parameter to control an additional device of the mobile working machine by means of the control of the hydraulic cylinder.

The invention also relates to a control unit for controlling an add-on device, in particular of a mobile work machine, wherein the control unit is set up to carry out or control the steps of the method described above for controlling the add-on device.

The subject matter of the invention is furthermore a working machine, in particular a mobile working machine, having an additional device, at least one hydraulic cylinder for moving the additional device, and the above-described control unit for controlling the additional device.

The subject matter of the invention is furthermore a computer program which is set up to carry out and/or control one or both of the above-described methods for controlling a hydraulic cylinder and/or for controlling an additional device.

The work machine may be a stationary work machine or preferably a mobile work machine. The work machine may be a work machine for construction, agricultural, forestry or logistics purposes. The mobile work machine may be, for example, an excavator, a wheel loader, a ground conveyor or an electric lift table. The stationary working machine may be, for example, a hydraulically driven industrial robot.

The additional equipment of the working machine may be additional equipment for working and/or treating agricultural and/or forestry and/or construction areas and/or additional equipment for transporting loads. The additional equipment may be, for example, a bucket, or a tool basket. The additional equipment may be arranged on a working arm, crane or hoist of the working machine.

The hydraulic cylinder or cylinder is configured to produce relative movement between the attachment and the work machine. To this end, the hydraulic cylinder comprises a housing and a piston. The piston can be moved relative to the housing by applying pressure to a hydraulic fluid, preferably a hydraulic fluid, and in particular can be introduced into and withdrawn from the housing.

The valve units assigned to the hydraulic cylinders are configured for loading the hydraulic fluid with pressure in a defined manner. The valve unit assigned to the hydraulic cylinder is thus configured for generating a relative movement between the piston and the housing of the hydraulic cylinder.

The valve unit may comprise one or more valves. The valve can be designed as a solenoid valve or as a pneumatically actuable or pneumatic valve. The valve unit may comprise a pilot valve, in particular of the electromagnetic type, and preferably a main valve assigned to the pilot valve, in particular pneumatically actuatable.

The relative movement between the piston and the housing of the hydraulic cylinder can be controlled by means of the control of the valve unit. Such a relative movement may be generated between the attachment and the work machine, in particular between the attachment and the working arm and/or crane of the work machine, on the basis of the arrangement of the hydraulic cylinder at the work machine.

Within the scope of the invention, control may be understood as: control in the sense that the output variable is generated on the basis of the input variable. Control may also and preferably be understood as control involving regulation in the sense that the actual value of the variable to be regulated is continuously determined and continuously compared with the target value of the variable to be regulated.

The nominal position of the add-on device may be a relative position of the add-on device in space with respect to the working machine comprising the add-on device or a spatial position in an external reference frame, for example a reference frame of a global satellite navigation system or a sensor unit detecting the position. The nominal position of the add-on device is preferably the spatial position of the Tool Center Point (TCP) of the add-on device. The target position of the additional device can be predefined, for example, for a working step of a working process to be performed by means of the working machine.

The determination of the setpoint value of the movement parameter as a function of the setpoint position of the additional device can be carried out by means of a software-based trajectory planning for the additional device or for the working machine. The setpoint value of the movement parameter can be determined taking into account at least part of the kinematics of the working machine.

The motion parameters of the hydraulic cylinder are parameters of the motion of the hydraulic cylinder. The movement of the hydraulic cylinder is preferably a relative movement between the piston and the housing of the hydraulic cylinder. The movement of the hydraulic cylinder may be a uniform movement or a preferably uniformly accelerated movement.

The motion parameter of the hydraulic cylinder may be a speed or an acceleration. The motion parameter is preferably the relative velocity or relative acceleration between the piston and the housing of the hydraulic cylinder.

The setpoint value of the movement parameter is the value of the movement parameter or the time profile of the value, according to which the movement of the hydraulic cylinder is to be carried out.

The valve parameter of the valve unit may be a parameter of one or more valves of the valve unit. The valve parameter may be the valve energization or the current strength of the solenoid valve. The valve parameter can also be a pressure, by means of which a pneumatically actuable valve is actuated. The valve parameter may furthermore be an opening area of a valve orifice of a valve of the valve unit.

A data-based model is understood within the scope of the present invention to be a mathematical model or mathematical algorithm which is designed to determine a value of a valve parameter as an output variable when a value of a movement parameter is predefined as an input variable. That is, in other words, the data-based model assigns values of the valve parameter to values of the kinetic parameter, or correlates or associates values of the kinetic parameter and the valve parameter with each other. 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 of a unit interacting with the hydraulic cylinder.

The data-based model is based on a learning data set or a training data set. These training data sets comprise value combinations, e.g. value tuples, of the motion parameters and the valve parameters and preferably the one or more further parameters. The training data set may be determined when operating the hydraulic cylinder, for example when operating a working machine comprising the hydraulic cylinder. In this case, the training data set corresponds to a combination of values which occur or exist when the hydraulic cylinder is operated.

The data-based model is designed to output the value of the valve parameter for each arbitrary value of the movement parameter technically achievable by means of the hydraulic cylinder, for example by means of a regression method, on the basis of the training data set. That is, in other words, the data-based model is set up for determining or machine learning associations or correlations for value combinations that are also not included by the training data set. In this case, the physical-technical model of the hydraulic cylinder is preferably not predefined for the data-based model. That is, in other words, the data-based model is a model generated using a method for machine learning.

The quality or quality of the data-based model is dependent on the deviation between a predefined setpoint value of the movement parameter and an actual value of the movement parameter, which is the actual value when the valve unit assigned to the hydraulic cylinder is controlled by using the setpoint value of the valve parameter determined by the data-based model. For a working range of the hydraulic cylinder, which is representative of the training data set, i.e. which comprises a sufficient number of relevant value combinations, a small deviation between the actual value of the movement parameter and the predefined setpoint value should be expected. For a working range of the hydraulic cylinder for which the training data set is not representative, i.e. does not comprise a sufficient number of associated value combinations, a significant deviation between the actual value of the movement parameter and the predefined setpoint value may occur.

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

The tolerance range of the valve parameter represents the range of values of the valve parameter tolerated or allowed for controlling the valve unit. Advantageously, the tolerance range for the setpoint value of the valve parameter is a subrange of the technically achievable or possible value range of the valve parameter. For example, the technically possible value range of the valve parameter may be a current intensity range which includes a current intensity which is greater than or equal to a first minimum value of the current intensity for the valve energization and which is less than or equal to a first maximum value of the current intensity for the valve energization. In this case, the tolerance range may be a current intensity range including a current intensity greater than or equal to a second minimum value of the current intensity for valve energization and less than or equal to a second maximum value of the current intensity for valve energization, wherein the second minimum value is greater than or equal to the first minimum value and the second maximum value is less than or equal to the first maximum value, and the two maximum values and the two minimum values are excluded from being equal. By means of this embodiment, the setpoint values of the valve parameters can be limited to a subset of the range of values that is technically possible in order to ensure safe operating conditions of the hydraulic cylinder, in particular of the working machine.

The method and the corresponding control unit improve the safety and reliability when automatically controlling a hydraulic cylinder or an additional device that can be moved by means of the hydraulic cylinder. The use of data-based models makes it possible to apply the method also to working machines with complex hydraulic behavior that can only be modeled in a cost-effective manner in a sufficiently detailed manner physically. In this case, by taking into account the tolerance range when determining the setpoint values of the valve parameters, it is ensured that the hydraulic cylinder or the additional device is always operated within a safe value range and therefore also within a safe value range even under rare operating conditions. This makes it possible to: the safety of a data-based control strategy of a partially or fully automated working machine is increased.

Advantageously, determining the nominal value of the valve parameter comprises: a temporary setpoint value of the valve parameter is determined, wherein the setpoint value of the valve parameter is determined as a function of the temporary setpoint value such that the determined setpoint value lies within a predefined and/or predefinable tolerance range for the setpoint value of the valve parameter. Preferably, in a first step, a temporary setpoint value of the valve parameter is determined, and subsequently in a second step, the setpoint value of the valve parameter is determined.

The temporary rating of the valve parameter may be a value of the valve parameter that is within or outside a tolerance range for the rating of the valve parameter. The nominal value of the valve parameter preferably corresponds to the temporary nominal value of the valve parameter if the temporary nominal value of the valve parameter is within the tolerance range.

If the temporary setpoint value of the valve parameter is outside the tolerance range, the temporary setpoint value of the valve parameter is changed or adapted or corrected in the determination of the setpoint value. It is conceivable that the determined setpoint value corresponds to a value of the tolerance range of the valve parameter which, with regard to the setpoint value of the received or predefined movement parameter, has a minimum distance from the provisional setpoint value.

By means of this embodiment, temporary target values outside the tolerance range are not used for controlling the valve unit, whereby critical operating states can be prevented.

It is also advantageous for the tolerance range to represent an admissible value range for the valve parameter, wherein the admissible value range, in particular the size of the admissible value range, depends on the value of the motion parameter. The size or width of the range of allowed values may be the same or preferably different for all values of the motion parameter. The size of the range of values of the valve parameter may be the width of the range of values. It is contemplated that the size of the range of values represents the difference between the maximum value of the range of values and the minimum value of the range of values.

In this case, it is advantageous to make the permissible value range, in particular the size of the permissible value range, dependent on the actual values of the other parameters of the hydraulic cylinder and/or of the working machine. Other parameters may correspond to time derivatives of the motion parameters. Other parameters may be pressure, for example the pressure of the hydraulic fluid of the hydraulic cylinder. It is also conceivable that the other parameter is the temperature of the hydraulic fluid of the hydraulic cylinder. It is also conceivable for the other parameter to be the rotational speed of the electric motor of the working machine.

It is conceivable that the actual values of the other parameters account for: a plurality of training data sets for defined values of the motion parameter and/or defined values of the valve parameter and/or other values defined by at least one of the other parameters considered by the data-based model. For example, the size of the tolerance range for values of the motion parameter having a large number of training data sets may be larger than the size of the tolerance range for values of the motion parameter having a smaller number of training data sets.

With this embodiment, the tolerance range can be adapted to the different motion parameters depending on the quality or quality of the data-based model, thereby increasing the efficiency of the control of the hydraulic cylinder or the additional device while ensuring operational safety.

It is furthermore advantageous if the method comprises a step of determining a tolerance range for a setpoint value of the valve parameter, wherein the tolerance range comprises values of the valve parameter which are determined when the hydraulic cylinder is operated at a frequency above a predefined and/or predefinable threshold value. For this purpose, the values of the valve and movement parameters and the frequency of occurrence of these values can be determined during operation of the hydraulic cylinder. The threshold value may be determined absolutely or relative to an average or maximum value of the frequency of occurrence of the value of the valve parameter. The threshold value preferably increases as the magnitude of the value of the motion parameter increases. For safety reasons, the width of the tolerance range is therefore smaller at higher values of the movement parameter.

During operation of the hydraulic cylinder, for each value of the valve parameter, at least one corresponding value of the movement parameter occurs with an increased probability. For each value of the valve parameter, the value of the respective motion parameter that occurs with its highest frequency when the hydraulic cylinder is operated may represent the desired or dominant value of the motion parameter. The desired or dominant value of the motion parameter may correspond to a value of the motion parameter in a stationary condition or a value of the hydraulic cylinder in a condition in which the value of the motion parameter does not change over time. In transient conditions of the hydraulic cylinder in which the value of the movement parameter can be changed over time, values of the movement parameter which deviate from the desired value of the movement parameter can also occur with a correspondingly reduced frequency of occurrence.

By means of this embodiment, the tolerance range can be determined in a particularly simple manner before the method is carried out. Furthermore, since the tolerance range is determined on the basis of values determined before the method is carried out or is determined off-line and is independent of the measurement signals detected at the run time of the method, the control of the hydraulic cylinder and the working machine also becomes robust against sensor failures.

It is furthermore advantageous if the setpoint value of the valve parameter is determined additionally as a function of at least one further parameter of the hydraulic cylinder and/or of the working machine, in particular the value of at least one further parameter. The other parameter is preferably a different parameter than the motion parameter. The other parameters may also correspond to time derivatives of the motion parameters. The other parameter may be a pressure, for example the pressure of the hydraulic fluid of the hydraulic cylinder. The further parameter is preferably the pressure difference between the pressure on the piston side of the hydraulic cylinder and the pressure on the piston rod side of the hydraulic cylinder. Alternatively or additionally, the further parameter is the difference between the LS pressure (load sense pressure) of the load sense system assigned to the hydraulic cylinder and the pressure provided by the pump unit for pressurizing the hydraulic fluid.

It is also contemplated that the other parameter is the temperature of the hydraulic fluid in the hydraulic cylinder. It is also conceivable that the further parameter is the rotational speed of the electric motor of the working machine.

The one or more other parameters are preferably comprised by a combination of values of a training data set on which the data-based model is based. That is, in other words, the data-based model preferably assigns values of the valve parameters to a combination of values of the kinetic parameters and values of the other parameters. With this configuration, the setpoint value of the valve parameter can also be determined with improved accuracy in a transient operating range in which no temporal changes in the value of the movement parameter occur.

It is also advantageous if the step of determining the setpoint value of the valve parameter comprises: the target state of an operating element of the working machine, in particular of the actuating lever, is determined, wherein the target value of the valve parameter is determined using the determined target state of the operating element. In this case, the setpoint state of the actuating element is determined as a function of the received setpoint value of the movement parameter using a data-based model, in particular an artificial neural network, and taking into account a predefined and/or predefinable tolerance range of the setpoint value of the valve parameter.

The operating element serves as a means for controlling the movement of the hydraulic cylinder. The nominal state of the operating element of the working machine may be a nominal position or a nominal condition of the operating element. The valve units assigned to the hydraulic cylinders are controlled in dependence on the state or position or condition of the operating element in order to move the hydraulic cylinders. For this purpose, a control signal for controlling the valve unit or the state of the valve unit is assigned to each state of the operating element.

By means of this embodiment, the setpoint state of the actuating element can be assigned to the setpoint value of the movement parameter in the first place, so that the valve unit can be controlled as a function of the state of the actuating element on the basis of software and hardware already present at the work machine.

A computer program product or a computer program with a program code which can be stored on a machine-readable carrier or storage medium, for example a semiconductor memory, a hard disk memory or an optical memory, and which is used, in particular when the program product or the program is executed on a computer or a device, to carry out, implement and/or handle the steps of the method according to one of the embodiments described above, is also advantageous.

Drawings

The invention is elucidated in more detail below by way of example in accordance with the accompanying drawings.

Wherein:

fig. 1 shows a schematic view of a control unit for controlling a hydraulic cylinder; and

FIG. 2 is a schematic diagram illustrating data-based adjustment of an attachment of a work machine;

FIG. 3 shows a graphical representation of the frequency of the position of the operating element of the excavator as a function of the rated speed of the hydraulic cylinder of the excavator; and

fig. 4 shows a flow chart of a method for controlling a hydraulic cylinder of a mobile work machine.

Detailed Description

Fig. 1 shows a schematic view of a control unit 1 for controlling a hydraulic cylinder of a work machine, such as an excavator.

The control unit 1 comprises a data-based model 10, which is designed as an artificial neural network 10, a memory unit 20, a limiting unit 26 and a determination unit 30. The control unit 1 is set up to determine a setpoint value for the setpoint state 27 or the state 27 of an operating element for controlling an additional device of the excavator in response to a setpoint value of the movement parameter 11, which is designed as the relative speed 11 of the hydraulic cylinder. The control unit 1 is also set up to determine a setpoint value of a valve parameter 29 assigned to the valve unit of the hydraulic cylinder on the basis of the setpoint state 27 of the operating element, in order to control the hydraulic cylinder by means of controlling the valve unit assigned to the hydraulic cylinder according to the determined setpoint value of the valve parameter 29.

The artificial neural network 10 is set up to receive a setpoint value for the relative speed 11 of the hydraulic cylinder. The artificial neural network 10 is also set up to receive the actual values of the

pressure differences

13, 15. The pressure difference 13 is preferably a pressure difference between the pressure on the piston side of the hydraulic cylinder and the pressure on the piston rod side of the hydraulic cylinder. The pressure difference 15 is the difference between the LS pressure (Load-Sensing-drop) of the Load-Sensing system assigned to the hydraulic cylinder and the pressure provided by the pump unit for loading the hydraulic fluid with pressure.

The artificial neural network 10 is also set up to determine a temporary value for the setpoint state 21 of the operating element on the basis of the received values 11, 13, 15. Additionally, the artificial neural network 10 is set up to output values for one or more of the factors 23, which describe a measure of the quality of the artificial neural network 10 in the operating range of the hydraulic cylinder specified by the

values

11, 13, 15. In a working range with many training data sets, because the quality of the data-based model is higher, the factor may have a larger value than in a working range with fewer training data sets, because the quality of the data-based model is lower in the latter case.

The memory unit 20 comprises at least one characteristic curve of the relative speed 11 and the desired or prevailing state 25 of the operating element, see fig. 3. The memory unit 20 is set up to output the value of the ideal or prevailing state 25 of the operating element in response to the nominal value of the relative speed 11 of the hydraulic cylinder.

The limiting unit 26 is set up for outputting the nominal value of the state 27 of the operating element in response to the temporary value of the nominal state 21 of the operating element, the ideal state 25 of the operating element and the factor 23. For this purpose, the limiting unit 26 is set up to determine the tolerance range width of the nominal value of the state 27 of the actuating element on the basis of the value of the ideal state 25 of the actuating element and the factor 23. The tolerance range extends from a value of ideal 25 that decreases by a factor of 23 to a value of ideal 25 that increases by a factor of 23.

The limiting unit 26 is also designed to take into account the tolerance range when determining the setpoint value of the state 27 of the actuating element. For this purpose, the limiting unit 26 is set up to determine whether the temporary setpoint value of the state 25 of the actuating element is within or outside the determined tolerance range. The value of the nominal state 27 corresponds to the temporary value of the nominal state 25 if the temporary nominal value of the state 25 of the operating element is within the tolerance range. If the temporary nominal value of the state 25 of the operating element is outside the tolerance range, the nominal value of the state 27 of the operating element corresponds to the value of the tolerance range having the smallest distance to the temporary nominal value of the state 25 of the hydraulic cylinder.

The determination unit 30 is set up to determine a setpoint value of the valve parameter 29 of the valve unit assigned to the hydraulic cylinder in response to the determined setpoint value of the state 27 of the operating element and to control the valve unit in accordance with the determined setpoint value of the valve parameter 29 in order to control the hydraulic cylinder of the mobile working machine.

Fig. 2 shows a schematic illustration of a data-based control of an additional device of a working machine, in particular an excavator, by means of a control unit 2. The adjustment includes: model-based speed adjustment of hydraulic cylinders of mobile work machines is performed in a manner similar to that of fig. 1. The hydraulic cylinder is designed to generate a movement of an additional device arranged on a work arm of the work machine, wherein a joint angle between joints of the work arm of the work machine is changed.

The adjusting unit 2 includes: attitude modifier 32 ("position controller"), inverse kinematics 34 ("inverse kinematics"), velocity modifier 36 ("velocity controller"), conditioning object 38 ("direct kinematics"), positive kinematics 40 ("direct kinematics"), one or more sensors 42 ("sensors"), and model-based filter 44 ("model-based filter").

The position controller 32 is designed to determine a setpoint speed 33 of the Tool Center Point (TCP) in response to a difference between setpoint coordinates 31 of the TCP and received actual coordinates 41 of the TCP, which are generated by the determination unit 30 for trajectory generation ("trajectory generator").

The inverse kinematics 34 is designed to determine a setpoint value 35 for the velocity of the joint angle or a setpoint value 35 for the velocity of the hydraulic cylinder of the working machine in response to the determined setpoint velocity 33 of the TCP.

The speed regulator 36 is designed to determine a setpoint value of the adjustment variable 37 in response to the determined setpoint value 35 for the speed of the joint angle or the determined setpoint value 35 for the speed of the hydraulic cylinder.

To this end, the speed Controller 36 includes a reverse operator behavior 36a ("reverse operator behavior") and a Feedback Controller 36b ("Feedback Controller") of the control object 38.

The retrobehavior 36a of the control object 38 is designed as a data-based model 10', in this exemplary embodiment as an artificial neural network 10', and is set up to output an adjustment variable 37 in response to the determined setpoint value 35 for the speed and the received pressure difference 51. The pressure difference 51 represents: the pressure difference between the pressure on the piston side of the hydraulic cylinder and the pressure on the piston rod side of the hydraulic cylinder and the difference between the LS pressure (load sense pressure) of the load sense system assigned to the hydraulic cylinder and the pressure provided by the pump unit for pressurizing the hydraulic fluid.

The feedback control device 36b is designed to adapt the manipulated variable 37 on the basis of the difference or deviation between the setpoint value 35 and the actual value 45 of the velocity of the joint angle or of the velocity of the hydraulic cylinder in response to the determined setpoint value 35 for the velocity and the actual value 45 of the velocity of the joint angle.

In response to the determined target value of the manipulated variable 37, the control object 38 derives therefrom an actual value 39 of the angle of the joint or an actual value 39 of the position or the actuating position of the hydraulic cylinder.

The control object 38 includes valve dynamics 38a ("valve dynamics"), valve geometry 38b ("valve geometry"), valve cross-sectional area 38c ("valve cross section"), and hydraulic cylinder 38d ("hydraulic cylinder"). The control object 38 represents a hydraulic cylinder arranged on the excavator, which is designed to control additional devices.

Due to the valve dynamics 38a of the valve assigned to the hydraulic cylinder, the valve is controlled to its spool position 55 corresponding to the adjustment 37.

Based on the valve geometry 38b of the valve, the valve in the position 55 of the valve slide results in a throttle plate cross section 57 of the valve.

The orifice cross section 57 causes an actual volume flow 59 of hydraulic liquid at the valve, based on the valve cross section 38c of the valve and the pressure difference 51.

The hydraulic cylinder 38d is designed to adjust the actual value 39 of the joint angle or the actual value of the state of the hydraulic cylinder in response to the determined actual volume flow 59 of hydraulic fluid and the load force 53 acting on the hydraulic cylinder 38 d.

The actual coordinates 41 of the TCP are derived from the actual value 39 of the joint angle or the actual value 39 of the speed of the hydraulic cylinder by means of the positive kinematics 40.

The one or more sensors 42 are designed to detect these actual coordinates 41 of the TCP. Furthermore, the sensors are designed to convert the detected actual coordinates into electronically processable signals 43.

The model-based filter 44 is designed to evaluate the electronically processable signal 43 of the sensor 42 in order to determine the actual coordinates 41 of the TCP, the actual value 39 of the joint angle or the actual value 39 of the position of the hydraulic cylinder and the actual value 45 of the velocity of the joint angle or the actual value 45 of the velocity of the hydraulic cylinder. The model-based filter 44 is also designed to provide the determined actual coordinates 41 of the TCP to the position controller 38, the determined actual value 39 of the joint angle to the inverse kinematics 34 and the determined actual value 45 of the velocity of the joint angle to the velocity controller 36.

For the above described conditioning, the artificial neural network 10' is trained prior to performing the conditioning.

The artificial neural network 10' is set up to machine-learn the pressure difference 51 in response to the manipulated variable 37 and to machine-learn the difference 61 between the actual value 39 of the joint angle and the joint angle 63 determined by the artificial neural network 10' or the difference 61 between the actual value 39 of the position of the hydraulic cylinder and the actual value 63 of the position of the hydraulic cylinder determined by the artificial neural network 10 '. The artificial neural network 10' is therefore set up to perform machine learning in such a way that the difference 61 is as small as possible, preferably zero.

Fig. 3 shows a diagram of the frequency of the position of the operating element of the excavator as a function of the rated speed of the hydraulic cylinder of the excavator. The illustration is based on measurement data detected during operation of the excavator.

The state or adjustment position x of the operating element configured as a joystick is plotted on the abscissa of fig. 3. The relative speed v of the hydraulic cylinder is plotted on the ordinate in fig. 3.

The relative frequencies at which the corresponding value combinations of the adjustment position x and the relative speed v occur when the excavator is operated are plotted in gray scale. In fig. 3, the frequency of occurrence of the value combinations increases from black to white or dark to bright. That is, the brighter the dots corresponding to a value combination are shown in fig. 3, the more frequent the value combinations.

FIG. 3 shows that: for each adjusted position of the joystick, corresponding to a very bright spot, the dominant speed appears with a significantly improved probability of occurrence. This speed can also be assumed to be an ideal speed. Around these prevailing speeds, regions or bands parallel to the speed axis can be seen, which can be interpreted as scattered forms. Such a dispersion or such a region is not present in the case of an ideal excavator. In the case of an ideal working machine, a speed is unambiguously assigned to each lever position, and the effect of the load force is optimally compensated by controlling the respective pump of the working machine.

In this sense, the width of the area or band is a measure for the deviation of the hydraulic system of the excavator from an ideal hydraulic device. The prevailing speed is preferably also the speed which the hydraulic cylinder reaches in stationary conditions, while other speeds also occur in the transient range, for example during a pressure build-up/acceleration process.

Fig. 4 shows a flow chart of a method for controlling a hydraulic cylinder of a mobile work machine. The method is provided with reference numeral 100 in its entirety.

In step 110, a setpoint value for a movement parameter of the hydraulic cylinder is received by means of a control unit of the mobile working machine.

In step 120, a setpoint value of the valve parameter assigned to the valve unit of the hydraulic cylinder is determined as a function of the received setpoint value of the movement parameter. In this case, the setpoint value of the valve parameter is determined by means of the control unit using a data-based model, in particular an artificial neural network, and taking into account a predefined and/or predefinable tolerance range of the setpoint value of the valve parameter.

In step 130, the valve unit assigned to the hydraulic cylinder is controlled by means of the control unit as a function of the set value of the valve parameter determined, in order to control the hydraulic cylinder of the mobile working machine.

If an embodiment includes an "and/or" association between a first feature and a second feature, this should be construed as an embodiment having both the first and second features according to one embodiment and either only the first or only the second feature according to another embodiment.

Claims

1. A method (100) for controlling a hydraulic cylinder of a, in particular mobile, working machine, the method comprising the steps of:

-receiving (110), by means of a control unit (1), a nominal value of a movement parameter (11) of the hydraulic cylinder;

-determining (120), by means of the control unit (1), a setpoint value of a valve parameter (29) assigned to a valve unit of the hydraulic cylinder from the received setpoint value of the kinetic parameter (11) using a data-based model (10), in particular an artificial neural network (10), and taking into account a predefined and/or predefined tolerance range for the setpoint value of the valve parameter (29); and

-controlling (130) a valve unit assigned to the hydraulic cylinder by means of the control unit (1) in accordance with the determined nominal value of the valve parameter in order to control the hydraulic cylinder of the, in particular, mobile working machine.

2. The method (100) of claim 1, wherein determining (120) the nominal value of the valve parameter (29) comprises: determining a temporary target value of the valve parameter, wherein the target value of the valve parameter (29) is determined as a function of the temporary target value such that the determined target value (27) lies within a predefined and/or predefinable tolerance range for the target value of the valve parameter (29).

3. The method (100) according to claim 1 or 2, wherein the tolerance range represents an allowed value range of the valve parameter, wherein the allowed value range depends on the value of the motion parameter (11).

4. Method (100) according to claim 3, characterized in that the permissible value range is furthermore dependent on actual values of other parameters (13, 15) of the hydraulic cylinder and/or of the working machine, in particular of time derivatives of the motion parameters and/or of pressure and/or of rotational speed and/or of temperature.

5. The method (100) according to one of the preceding steps, characterized by the step of determining a tolerance range for the setpoint value of the valve parameter (27), wherein the tolerance range comprises values of the valve parameter which are determined if the hydraulic cylinder is operated at a frequency above a predefined and/or predefinable threshold value.

6. The method (100) according to one of the preceding steps, characterized in that the tolerance range for the nominal value of the valve parameter (29) is a subrange of the technically achievable value range of the valve parameter.

7. Method (100) according to one of the preceding steps, characterized in that the setpoint value of the valve parameter (29) is determined in addition as a function of a time derivative and/or a pressure and/or a rotational speed and/or a temperature of at least one further parameter (13, 15) of the hydraulic cylinder and/or of the working machine, in particular of the movement parameter.

8. Method for controlling an additional device of a working machine, in particular of a mobile type, wherein the additional device can be moved relative to the working machine by means of a hydraulic cylinder, comprising the following steps:

-receiving the nominal position of the additional device by means of a control unit (1);

-determining a nominal value of a movement parameter (11) of the hydraulic cylinder from the received nominal position of the additional device by means of the control unit (1);

-determining (120), by means of the control unit (1), a setpoint value of a valve parameter (29) assigned to a valve unit of the hydraulic cylinder from the received setpoint value of the kinetic parameter (11) using a data-based model (10), in particular an artificial neural network (10), and taking into account a predefined and/or predefinable tolerance range for the setpoint value of the valve parameter (29); and

-controlling (130) a valve unit assigned to the hydraulic cylinder by means of the control unit (1) in dependence on the determined nominal value of the valve parameter (29) in order to control an additional device of the, in particular, mobile working machine by means of the control of the hydraulic cylinder.

9. The method of claim 8, wherein the step of determining (120) the nominal value of the valve parameter (29) comprises: a setpoint state (27) of an operating element of the working machine, in particular of a control lever, is determined, wherein a setpoint value of the valve parameter (29) is determined using the determined setpoint state (27) of the operating element.

10. A control unit (1) for controlling a hydraulic cylinder of a working machine, in particular a mobile working machine, wherein the control unit (1) is set up for

-receiving a nominal value of a motion parameter (11) of the hydraulic cylinder;

-determining a setpoint value of a valve parameter (29) assigned to a valve unit of the hydraulic cylinder from the received setpoint value of the kinetic parameter (11) using a data-based model (10), in particular an artificial neural network (10), and taking into account a predefined and/or predefinable tolerance range for the setpoint value of the valve parameter (29); and

-controlling a valve unit assigned to the hydraulic cylinder in dependence on the determined nominal value of the valve parameter (29) in order to control the hydraulic cylinder of the, in particular mobile, working machine.

11. A control unit (1) for controlling an add-on device of a, in particular, mobile, working machine, wherein the add-on device is movable relative to the working machine by means of a hydraulic cylinder, and the control unit (1) is set up for:

-receiving a nominal position of the add-on device;

-determining a nominal value of a movement parameter (11) of the hydraulic cylinder as a function of the received nominal position of the additional device;

-determining a setpoint value of a valve parameter (29) assigned to a valve unit of the hydraulic cylinder from the received setpoint values of the kinetic parameter (11) using a data-based model (10), in particular an artificial neural network (10), and taking into account a predefined and/or predefinable tolerance range for the setpoint value of the valve parameter (29); and

-controlling the valve units assigned to the hydraulic cylinders as a function of the determined setpoint values of the valve parameters (29) in order to control additional devices of the in particular mobile working machine by means of the control of the hydraulic cylinders.

12. A working machine, in particular a mobile working machine, having an additional device, at least one hydraulic cylinder for moving the additional device, and a control unit (1) according to claim 11 for controlling the additional device.

13. A computer program set up for carrying out and/or controlling 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 the computer program of claim 13 stored thereon.