METHOD FOR CONTROLLING A SCREWING PROCESS

Abstract

A method for controlling a screwing process, includes during the screwing process screwing a screw into a component with an electrical screwing device; detecting during the screwing process an actual course of at least one process parameter of the screwing; testing whether the actual course has a pattern which predicts an error of the screwing process; and terminating the screwing process early when the actual course has said pattern.

Claims

1. A method for controlling a screwing process, comprising: during the screwing process screwing a screw into a component with an electrical screwing device; detecting during the screwing process an actual course of at least one process parameter of the screwing; testing whether the actual course has a pattern which predicts an error of the screwing process; and terminating the screwing process early when the actual course has said pattern.

2. The method of claim 1, further comprising comparing the actual course detected during the screwing process with at least one erroneous course of an erroneous screwing process that has the pattern which has occurred during the erroneous screwing process prior to an occurrence of an error in the erroneous screwing process, wherein the pattern is identified in the actual course when the actual course corresponds to the erroneous course at least during a time interval.

3. The method of claim 2, wherein the at least one erroneous course of the erroneous screwing process is deduced from at least one other erroneous course which was detected during another erroneous screwing process performed prior to the erroneous screwing process.

4. The method of claim 1, wherein the at least one process parameter is a torque of the electrical screwing device.

5. The method of claim 1, further comprising performing multiple said screwing process with multiple respective screwing devices, transmitting at least one erroneous course resulting during at least one of the multiple screwing processes respectively from at least one of the multiple screwing devices screwing from the at least one electrical screwing device to a central higher-level data processing unit in real time, analyzing the at least one erroneous course by the central higher-level data processing unit in real time and transmitting the at least one erroneous course all of the multiple electrical screwing devices in real time.

6. A system for controlling a screwing process in which a screw is screwed by an electrical screwing device into a component, said system comprising: at least one sensor configured to detect during the screwing process an actual course of at least one process parameter of the screwing process; and at least one control unit configured to test whether the actual course has a pattern that predicts an error of the screwing process, and to prematurely terminate the screwing process when the actual course has said pattern.

7. The system according to claim 6, wherein the at least one control unit is arranged in the screwing device.

8. The system of claim 6, wherein the at least one control unit is arranged outside of the screwing device and is in data communication with the screwing device.

9. The system of claim 6, wherein the at least one control unit includes a data processing unit.

10. The system of claim 6, wherein the at least one control unit includes a data memory, in which at least one erroneous course of the at least one process parameter that has occurred in an erroneous screwing process is stored.

11. The system of claim 6, further comprising a central higher-level data processing unit in data communication with multiple electrical screwing devices.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0029] Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which:

[0030] FIG. 1 shows a diagram of an embodiment of the method according to the invention.

[0031] FIG. 2 shows a schematic representation of an embodiment of the system according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0032] Throughout all the Figures, same or corresponding elements may generally be indicated by same reference numerals. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figures are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.

[0033] The diagram of FIG. 1 for performing the embodiment of the method according to the invention with the system 2 schematically shown in FIG. 2, includes an abscissa 4 on which the time is plotted, and an ordinate 6 on which an actual course 8 of a process parameter, here a torque, of an electric screwing device 10 of the system 2 is plotted, which results in an actually performed screwing process.

[0034] When performing the screwing process, a screw 12 can be screwed into a component 14 with the screwing device 10. The screwing device 10 includes a control unit 16 which includes a data processing unit 18 internal to the screwing device, and a sensor 20 for detecting at least one process parameter during the screwing process.

[0035] FIG. 2 further shows a first data processing unit 22, which in the illustrated embodiment is arranged outside the screwing device 10 and is connected with the screwing device 10 via a connection 24 for exchanging data. This first data processing unit 22 outside of the screwing device 10 is connected with a second higher-level data processing device 26 also via a connection 28 for exchanging data.

[0036] Beside the screwing device 10 shown in detail in FIG. 2 the embodiment of the system 2 also includes a further screwing device 30, 32, which although being depicted smaller, includes the same components as the first screwing device 10. Hereby this first at least one further screwing device 30, 32 is connected with the second higher-level data processing unit 26. All screwing devices 10, 30, 32 are connected with each other via this higher-level central data processing unit 26.

[0037] During assembly of a plurality of components 14 by performing multiple screwing processes, all screwing devices 10, 30, 32 detect with sensors process parameters and transmit the process parameters in real time to the central higher-level data processing unit 26, which analyzes the process parameters. In an embodiment the actual courses of respective process parameters that accompany the screwing processes are analyzed in which during a respective erroneous screwing process an error has occurred in real time.

[0038] In an analysis of such an erroneous actual course of at least one process parameter it is tested whether this process parameter has a pattern 34, wherein the error 36 has occurred during the erroneous screwing process only after the pattern 34. Hereby it is conceivable that the pattern 34 and the error 36 are connected with each other or are correlated with each other, wherein the error 36 has resulted during the screwing process at a time point after the pattern 34 has occurred.

[0039] A plurality of erroneous courses that were sensed by the screwing devices 10, 30, 32 are analyzed by the central higher-level data processing unit and are subsequently transmitted to the control units 16 of the screwing devices 10, 30, 32 in real time, wherein a respective one of such erroneous course is to be understood and/or used as a negative example for a correct target course of a corresponding process parameter.

[0040] In a screwing process actually performed by the screwing device 10 the actual course 8 of the process parameter detected during operation is compared with at least one erroneous course. When such a comparison shows that the pattern 34 occurs during the actual course 8, the screwing process is immediately automatically terminated before the error 36 that is expected based on the pattern even occurs. It is thus possible within the framework of the method to predict the error 36 in time and/or early by detecting the pattern 34 in the actual course 8 and to avoid the error by terminating the screwing process.