IMPLEMENT AND METHOD OF ACTUATING A DRIVE THEREOF

Abstract

This disclosure relates to an implement, in particular crane or excavator, comprising a drive, a control unit, a measuring device and a memory. A component of the implement can be moved by means of the drive, wherein the drive can be actuated via the control unit. The measuring device can detect an actual variable relating to a movement of the driven component. In the memory, at least one characteristic curve for the actuation of the drive is stored. On the basis of a detected deviation, the control unit according to the disclosure can independently adjust the characteristic curve stored already or generate a new characteristic curve and store the same in the memory. The disclosure furthermore relates to a method of actuating a drive of such an implement.

Claims

1. An implement comprising: a drive by means of which a component can be moved, a control unit by means of which the drive can be actuated, a measuring device by means of which an actual variable relating to a movement of the actuated component can be detected, and a memory in which at least one characteristic curve for the actuation of the drive is stored, wherein the control unit is adapted to determine a control variable for the actuation of the drive in dependence on a setpoint variable relating to the movement of the component with reference to a stored characteristic curve, to compare the detected actual variable with the setpoint variable and to detect a deviation between the same and to adjust the characteristic curve or to generate a new characteristic curve on the basis of the deviation and to store the same in the memory.

2. The implement according to claim 1, wherein the control unit is adapted to carry out the detection of the actual variable and the comparison with the setpoint variable several times during an operating period of the implement.

3. The implement according to claim 1, wherein in the memory a plurality of characteristic curves are stored, wherein the control unit is adapted to determine the control variable in dependence on the setpoint variable and at least one further variable with reference to the stored characteristic curve.

4. The implement according to claim 3, wherein the control unit is adapted to adjust a plurality of stored characteristic curves on the basis of the deviation between actual variable and setpoint variable and by taking account of the further variable, or to generate a plurality of new characteristic curves and store the same in the memory.

5. The implement according to claim 2, wherein the control unit is adapted to analyze a detected deviation between actual variable and setpoint variable and automatically carry out an adjustment of the stored characteristic curve or a generation and storage of a new characteristic curve.

6. The implement according to claim 2, wherein by means of the measuring device a plurality of measurement values of the actual variable can be detected at different times during the operating period of the implement, wherein the control unit is adapted to select one or more measurement values from the detected measurement values of the actual variable for the comparison with the setpoint variable.

7. The implement according to claim 1, wherein the control unit is adapted to generate a new characteristic curve and store it in the memory on the basis of a detected deviation between actual variable and setpoint variable and to furthermore determine the control variable with reference to an old characteristic curve.

8. The implement according to claim, 7, wherein the control unit is adapted to adjust the new characteristic curve upon detection of a further deviation between newly detected actual variable and setpoint variable and/or to generate another new characteristic curve and store it in the memory and to furthermore determine the control variable with reference to an old characteristic curve.

9. The implement according to claim 8, wherein the control unit is adapted to change the determination of the control variable with reference to an old characteristic curve to a determination of the control variable with reference to a newly generated characteristic curve, wherein the change is effected when a limit value for a deviation between actual variable and setpoint variable and/or between old and newly generated characteristic curve is exceeded, when a defined period of time expires and/or when a limit value for another detectable variable is exceeded or fallen short of.

10. The implement according to claim 9, wherein the control unit is adapted to carry out the change from the old to the new characteristic curve automatically.

11. The implement according to claim 1, wherein in a calibration mode the control unit is adapted to generate at least one new characteristic curve and store it in the memory by the targeted actuation of the drive and the sequential detection of a plurality of values of the actual variable during the movement of the component, wherein the calibration mode can be activated manually and/or automatically.

12. The implement according to claim 1, wherein the control unit is adapted to take account of operating information stored in the memory when the deviation between actual variable and setpoint variable is detected and/or when the detected deviation is analyzed, which operating information relates to an exchange, a repair, a period of use or a wear of at least one component of the implement.

13. The implement according to claim 1, wherein the drive is a hydraulic drive which can be pilot-controlled via a hydraulic actuator.

14. A method of actuating the drive of the implement according to claim 5, comprising the following steps: determining the control variable in dependence on the setpoint variable with reference to the stored characteristic curve by means of the control unit, actuating the drive by means of the control unit on the basis of the control variable, in order to move the component, detecting the actual variable by means of the measuring device, comparing actual variable and setpoint variable by means of the control unit, detecting the deviation between actual variable and setpoint variable by means of the control unit, and adjusting the stored characteristic curve or generating and storing the new characteristic curve on the basis of the detected deviation by means of the control unit.

15. The method according to claim 14, wherein the actual variable is detected several times in a row during the operating period of the implement and is compared with the setpoint variable, wherein during operation the old stored characteristic curve is adjusted and/or the new characteristic curve is generated and the same is adjusted dynamically, wherein the control variable furthermore is determined with reference to an old stored characteristic curve until the limit value for the deviation between actual variable and setpoint variable and/or between the old stored characteristic curve and the newly generated characteristic curve is exceeded, until a defined time period expires and/or until a limit value for another detectable variable is exceeded or fallen short of, whereupon the control variable is determined from this time with reference to the newly generated characteristic curve.

16. The implement according to claim 1, wherein the implement is a crane or excavator.

17. The implement according to claim 2, wherein the control unit is adapted to carry out the detection of the actual variable and the comparison with the setpoint variable at regular time intervals.

18. The implement according to claim 3, wherein the further variable can be detected by means of a further measuring device and relates to an operating parameter of the implement, a temperature and/or a load.

19. The implement according to claim 10, wherein the control unit is adapted to carry out the change outside the operation of the implement.

20. The implement according to claim 13, wherein the control variable relates to a current value for the actuation of the drive or actuator and/or the setpoint variable relates to a speed.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0042] Further features and details of the disclosure can be taken from the exemplary embodiments explained below with reference to the Figures, in which:

[0043] FIG. 1: shows a schematic representation of the method of the disclosure according to a first exemplary embodiment; and

[0044] FIG. 2: shows a schematic representation of the method of the disclosure according to a second exemplary embodiment.

DETAILED DESCRIPTION

[0045] FIG. 1 schematically shows a first exemplary embodiment of the adaptive characteristic curve or characteristic map adjustment of the method according to the disclosure. In the following, the adaptive system of the disclosure will be described with reference to the example of a crane. However, the disclosure is not limited to cranes, but can be used for any kind of implement.

[0046] In the exemplary embodiment shown in FIG. 1 a crane gear or a hoisting winch for lifting a load is actuated via a hydraulic drive. The drive is pilot-controlled via a hydraulic valve, wherein the valve is electronically actuated via a control unit of the crane or a crane controller. In the memory of the implement characteristic maps 10 are stored for implementing a setpoint speed in the hoisting gear, which are used for determining a corresponding current value for actuating the drive. The characteristic maps 10 in part take account of the non-linear characteristic values of the hydraulic system (e.g. valve characteristic curves).

[0047] The characteristic maps 10 are grouped with reference to measurable variables such as temperature, load or torque. Depending on the temperature or the load to be lifted, a particular characteristic map 10 hence is used for determining the current value. This determination can be made for example by means of interpolation between discrete characteristic values stored in the characteristic map 10. As an alternative to characteristic maps, individual characteristic curves can also be stored and grouped correspondingly.

[0048] In known systems, the dependencies of the characteristic maps 10 due to aging or wear (e.g. leakage increased over time) or exchange of components are not taken into account or require a manual adjustment of the characteristic maps 10 in the factory. Possible inaccuracies typically are manually adjusted to the detriment of other operating points (e.g. slower movement, in-between loads etc.). To improve the actuation and reduce or abolish the necessity of manual adjustments, the present disclosure provides an adaptive characteristic map adjustment.

[0049] In dependence on the load to be lifted and the existing temperature (both parameters are detected by means of sensors provided for this purpose), a suitable characteristic map 10 is selected from the stored characteristic maps 10. With reference to a setpoint speed specified for example by an operator input (step S1), a current value is determined from the selected characteristic map 10 for the actuation of the hoisting gear or the valve piloting the hoisting gear, whereupon the actuation is effected by the crane controller (step S2). The actuation leads to a movement of the hoisting gear (step S3), i.e. to a lifting of the load.

[0050] By means of a measuring device, the actual speed of the hoisting gear (for example the speed of rotation of the hoisting winch or the speed of the traction means or traction cable) is measured and provided to the crane controller (step S4). The crane controller compares the measured actual speed with the specified setpoint speed (step S5). When these values differ from each other and exceed a limit value stored in the crane controller or in the memory (this limit value can be defined globally or likewise depend on further parameters, such as e.g. the movement or hoisting speed, temperature, load, an operating parameter of the crane or the like), the crane controller detects a deviation and carries out a characteristic map adaption (step S6).

[0051] By means of the characteristic map adaption, the current values for the actuation of the hoisting gear can be adapted to the deviations and thus, these deviations can be compensated, which result for example from component aging, a different component characteristic curve due to an exchange of components or from component tolerances. In other words, different current values are determined with reference to the adapted characteristic maps 10 to achieve the same setpoint speed.

[0052] In normal crane operation, the actual speed ideally is detected continuously (step S4) and compared with the setpoint specifications (step S5) so that deviations can be detected promptly and at any time. Moreover, larger data quantities thereby are available for a more robust characteristic map adaption (step S6).

[0053] Furthermore, special filters and/or algorithms can be provided, by means of which the measurement values or measurement cycles to be used or exploited for the comparison can be selected from the measured data. The actual and setpoint speeds can be maximum values. In addition, a fuzzy logic, RMS and/or other suitable methods can be used for the analysis of the deviations between actual and setpoint speeds. The characteristic map adaption (step S6) can be effected by means of a self-learning algorithm or by using machine-learning methods.

[0054] Due to the characteristic map adaption according to the disclosure, the quality of the (pilot) control is increased distinctly and systematic malfunctions and deviations are compensated by the superimposed regulation (adaption of the characteristic maps 10).

[0055] In the exemplary embodiment of FIG. 1, a direct feedback is effected, i.e. the characteristic maps 10 used for determining the current value (i.e. the control variable or regulating variable) are adjusted directly by the crane controller. An alternative exemplary embodiment is shown in FIG. 2. Here, the characteristic maps 10 currently used for determining the current values (also referred to as old, active or stationary characteristic maps or basic characteristic maps 10) are not adjusted, but upon detection of corresponding deviations between actual and setpoint speeds in step S5 new characteristic maps 12 (also referred to as new, inactive or passive characteristic maps 12) initially are generated and stored in the memory (or in a separate memory to which the crane controller has access) in parallel to the active characteristic maps 10 (step S6).

[0056] The characteristic map adaption continued in the further crane operation, is applied only to the inactive characteristic maps 12 so that the active characteristic maps 10 remain unchanged. A direct feedback thereby is avoided, which renders the system more robust. A change from the old characteristic maps 10 to the new optimized characteristic maps 12 in the determination of the current values (step S7) is effected at a fixed time, for example upon detection of a deviation between old and new characteristic maps 10, 12 or when a deviation between actual and setpoint speed lies above a defined limit value or threshold value (step S8). The change is effected in particular during a downtime of the crane so that the operator is not confronted with a sudden change in the control dynamics of the crane.

[0057] From the time of the change (step S7) the newly adjusted or optimized characteristic maps 12 are used for a determination of the current values or for actuation (step S2). The old characteristic maps 10 either are deleted or remain stored, for example as reference values which allow a future evaluation as regards the aging/wear of the components. Now, new characteristic maps 12 can again be generated in parallel and be adjusted by means of the continued measurement of the actual speed (step S4), until a new change in turn is effected (step S7).

[0058] In the exemplary embodiments described here, all steps are carried out locally in the implement. It is likewise conceivable, however, that one or more steps are outsourced to an external computer unit or cloud, for example the comparison between actual variable and setpoint variable, the selection of the measurement data used for this comparison, the evaluation of the deviations, the generation and possibly further adjustment of new characteristic curves and/or the decision as to when a change from the old to the new characteristic curves is effected.

LIST OF REFERENCE NUMERALS

[0059] 10 stored characteristic map [0060] 12 newly generated characteristic map [0061] S1 specified setpoint speed [0062] S2 actuation [0063] S3 movement [0064] S4 detection of actual speed [0065] S5 comparison of actual and setpoint speed [0066] S6 characteristic map adaption [0067] S7 switch between old and new characteristic map [0068] S8 initiation of the change