WO2008025304A1

WO2008025304A1 - Monitoring method

Info

Publication number: WO2008025304A1
Application number: PCT/DE2006/001516
Authority: WO
Inventors: Hubert Bellm; Wolfgang Ens; Herbert Grieb
Original assignee: Siemens Aktiengesellschaft
Priority date: 2006-08-30
Filing date: 2006-08-30
Publication date: 2008-03-06
Also published as: DE112006004117A5

Abstract

The invention relates to a method for monitoring a facility that is involved in a production process, especially a packaging machine, comprising at least one drive (10). According to this method, at least once drive-related reference data (24) are acquired during operation of the drive (10), especially during a reference travel, and at least one reference data item is stored in relation to these data (24). Drive-related data (26) are acquired in a continuous manner or at defined or definable intervals and at least one actual data item is derived therefrom. The one or more actual data are compared with the reference data item and an action is triggered if the data item deviates by more than one defined or definable threshold value.

Description

description

monitoring procedures

As a monitoring method, the invention relates to a method for monitoring a device involved in a production process, in particular a packaging machine ^, with one or more drives.

In packaging machines are often downtime, depending on the application z. B. are caused by packaging residues in the machine, filling in a sealed seam or incomplete filled packaging. Furthermore, there are failures due to mechanical defects in the drive of the machine, such as loose elements for power transmission, such. As timing belt, or defective .Lager and the like.

So far, the machines are usually monitored by the operator visually and maintained at fixed intervals. Downtimes are unpredictable and are essentially accepted.

Accordingly, it is an object of the present invention to provide a monitoring method with which standstill times or deterioration of the performance can be virtually predicted. This in turn is based on a prediction of a situation that would lead to a standstill or reduced performance of the machine without precautionary maintenance.

This object is achieved with the features of claim 1. For this purpose, in a method for monitoring a device involved in a production process, in particular a packaging machine, provided with at least one drive that during operation of the drive at least once drive-related reference data is recorded and at least one reference date is stored with respect to these reference data that continuously or drive-related data are recorded at predetermined or predefinable times and at least one momentum is derived therefrom and that the or each instantaneous date is compared with the reference datum and an action is triggered if there are deviations by more than a predefined or specifiable threshold value.

The term "drive-related" here and in the following means that the respective data are obtained by monitoring the drive, ie a setpoint value which can be specified in a manner known per se, eg a speed setpoint, is not a drive-related datum. However, an instantaneous speed, ie a value determined during control of the drive to maintain the speed setpoint value, ie monitored value, is a drive-related datum in this terminology.

The invention is based on the recognition that, in the case of electronically controlled drives, wherein the electronic control includes a processing function included in the drive with z. As a memory and a microprocessor o- the like - ie a "self-intelligence" - requires, from the drive above as the current date called performance indicators can be determined as a performance indicator comes, for example, a time integral of the motor current and the like The current momentum can be continuously checked as a measure of "health" of the respective machine during production or evaluated in production breaks by comparison with a reference run. Before a standstill or reduced performance of the machine occurs, it can be deduced from the medium-term tendency of the instantaneous date, ie the respective performance indicator, whether operator measures or maintenance of the machine are required.

The advantage of the method described is that with the help of the performance indicators in advance, ie before it comes to a standstill of the respective machine, an indication for the operator to existing problems can take place. Necessary interventions can then be carried out cost-optimally planned.

If the performance indicators can be formed using the information already available in the drive, a determination of the "health" can be made without additional sensors and thus without mechanical intervention in the machine, which saves costs and can also be retrofitted on machines already in operation.

Overall, this results in the situation that during production rejects and downtimes are minimized and accordingly an output of the respective machine is maximized.

Relationships used in subclaims indicate the further development of the subject of the main claim by the features of the respective subclaim; they should not be construed as a waiver of obtaining independent, objective protection for the feature combinations of the dependent claims. Furthermore, with a view to an interpretation of the claims in a closer concretization of a feature in a subordinate claim, it is to be assumed that such a restriction does not exist in the respective preceding claims.

If a rotary encoder is assigned to the drive and the drive-related reference data and the drive-related data result from an output signal supplied by the rotary encoder, a standard deviation of an acceleration signal or the like at this rotary encoder during constant travel and the like can be considered as a performance indicator ,

On the one hand, production breaks can be considered to determine the drive-related reference data. Next or additional It can also be provided that the determination of the drive-related reference data takes place during the production process.

If the drive-related reference data are recorded during production breaks, this can be done without affecting the production process. Preferably, it is provided that during the production break a reference run is performed to create defined conditions. If the antriebsbezoge- nen reference data during the production process are aufgenom ^¬ men, this can also be non-reactive with respect to the production process if predefined or predetermined characteristic phases of movement for receiving the reference data are used.

Preferably come as a drive-related reference data and / or data acceleration or power consumption of the drive into consideration. More preferably come as a reference date and current date, so as performance indicators, which are derived from the drive-related reference data or data, a standard deviation or a higher statistical moment, an autocorrelation, a characteristic frequency or a characteristic frequency range of the drive-related reference data or the drive-related Into consideration.

Alternatively or additionally, the determination of performance indicators may also be based on a temporal change of defined movement sequences, comparison of the integral of the received electrical power over a cycle, deviation from reference curve, definition of envelopes, gradient change, etc.

In addition to the evaluation of already existing information, additional sensors can be used. Since the machines generally work cyclically (defined sequences of movements are repeated over and over again), a management of performance indicators can also be brought about by the comparison of characteristic sub-processes.

Then, it becomes possible to dispense with homing or the like by taking the drive-related reference data and an associated reference data during a first such cycle or sub-cycle or a characteristic portion of such a cycle or subcycle, and the drive related data and an associated instantaneous date be recorded in a subsequent cycle.

The or each embodiment is not to be understood as limiting the invention. Rather, numerous changes and modifications are possible within the scope of the present disclosure, in particular those variants, elements and combinations, for example, by combination or modification of individual described in conjunction with the general or specific description part and in the claims and / or the drawings Characteristics or elements or method steps for the expert in terms of solving the problem can be removed and lead by combinable features to a new subject or to new process steps or procedural steps.

An embodiment of the invention will be explained in more detail with reference to the drawing. Corresponding objects or elements are provided in all figures with the same reference numerals.

Show in it

1 shows a schematically simplified representation of a device involved in a production process with a drive,

FIG. 2 shows an example of drive-related reference data determined during operation of the drive. acceleration signal in a driven by the drive tight tensioned timing belt and

FIG. 3 shows an acceleration signal with a loosened toothed belt as an example of drive-related data determined during operation of the drive.

1 shows a greatly simplified example of a device involved in a production process with at least one drive 10, a kinematic chain with a controlled by the drive motor 12, a driven by the engine 12 gear, z. B. in the form of a toothed belt 14, and a driven load 16. The engine 12 includes in a conventional manner not shown bearing, z. B the ball bearing, the Lagerunge an effective to drive the belt 14 motor shaft 18. The timing belt 14 itself runs in the illustrated embodiment on timing pulleys 20, 22, which are also stored in basically known per se and not shown manner.

The toothed belt drives 14, 20, 22 and bearings described above are generally used as construction elements in production machines, in particular packaging machines. If toothed belts 14 are incorrectly mounted too loosely or have become loose due to wear or if a ball bearing has too much play, malfunctions of the respective machine occur. It would therefore be desirable, loose timing belt z. B. to recognize by a test run in production breaks.

So far, defective design elements, ie in particular loose or worn toothed belt or chain drives, could only be detected by additional sensors.

In contrast, for monitoring a device involved in a production process, in particular a packaging machine, with at least one drive 10, the invention proposes a method in which during operation of the drive 10 at least once drive-related reference data 24 are added. Thereafter, drive-related data 26 are recorded continuously or at predefined or predefinable times. For this purpose, a rotary encoder 28 assigned to the motor 12 is provided. An output signal of the rotary encoder 28, z. As the time course of an acceleration signal is transmitted via a designated signal line 30 to the drive 10. The drive 10 provides the output signal of the rotary encoder 28 as drive-related reference data 24 and as drive-related data 26.

The drive-related data 26 are then compared directly or indirectly with the reference data 24. In case of deviation by more than a predetermined or predefinable threshold, an action is triggered, the z. B. operator indicates an imminent need for maintenance or to be attended standstill of the machine.

In addition to a possible direct comparison of drive-related data 26 and drive-related reference data 24, which may be numerically complex because of the data sets to be examined, an indirect comparison of these data is particularly suitable, by providing a reference data and the drive-related data 26 from the drive-related reference data 24 a momentum is derived. By deriving the reference or instantaneous date, one or more features of the respectively underlying acceleration signal (eg standard deviation or higher statistical moments, autocorrelation, spectrum, characteristic frequencies and the like) are determined.

By traversing a characteristic velocity profile z. B. in production breaks and the calculation of characteristics of the acceleration signal during cruise phases can be seen loose timing belt 14 or a larger bearing clearance by z. For example, the determined value of the standard deviation as an example of an instantaneous date with an heren, when "good" timing belt determined value, ie the associated reference date, is compared.

The advantage of the described method is, in particular, that no additional sensor system on the toothed belt drive is ^required . All it takes is the position and speed sensor, which is already available in the engine and drive.

Based on the illustration in FIG. 2 and FIG. 3, the differences of the recorded drive-related data or reference data will be explained below using the example of a tightly tensioned toothed belt 14 (FIG. 2) and a loose toothed belt 14 (FIG. 3).

In FIG. 2, a desired speed 32, an actual speed 34, an actual acceleration (acceleration) 36 and a torque 38 are shown for operating the device shown in FIG. 1 with the toothed belt 14 tensioned. The same quantities are shown in FIG. 3 for a situation with a loose toothed belt 14.

Comparing the illustrations in FIG. 2 and FIG. 3, it can be seen that there are hardly any deviations between the actual speed 34 with the toothed belt 14 (FIG. 2) and the loose toothed belt 14 (FIG. 3). If, on the other hand, one compares the acceleration 36 with the toothed belt 14 (FIG. 2) and the loose toothed belt 14 (FIG. 3), clear differences can be briefly described as significant noise on the acceleration signal 36 with a loose toothed belt 14 (FIG. 3).

If the standardized deviation is taken as the basis for the investigated characteristic of the output signal of the rotary encoder 28 and if a situation as shown in FIG. 2 is used to record drive-related reference data, whereby a partial course of the local acceleration signal 36 is detected as drive-related reference data 24, this is referred to as drive-related Date the standard deviation of the local Acceleration signal 36 calculated. If the tension of the toothed belt 14 decreases during operation, z. B. a situation that corresponds to the situation shown in FIG 3 or at least comes close. The corresponding partial course of the local acceleration signal 36 is recorded as drive-related data 26 and the standard deviation is formed as the instantaneous data. However, the standard deviation of the acceleration signal 36 in FIG. 2 (reference datum) is significantly lower than the standard deviation of the acceleration signal 36 in FIG. 3 (instantaneous datum). If the current date differs from the reference date by more than a predetermined or predefinable threshold, an action is initiated that alerts operating personnel to the need for maintenance or a service shutdown of the particular machine. In this context, comes as an action triggering an audible or visual warning or the like into consideration.

Thus, the invention can be briefly represented as follows:

A method is provided for monitoring a device involved in a production process, in particular a packaging machine, with at least one drive 10, in which at least one drive-related reference data 24 is recorded during operation of the drive 10 and at least one reference datum in relation to FIG this data 24 is stored, in which drive-related data 26 are recorded continuously or at predefined or predefinable points in time and at least one instantaneous date is derived from it and in which the or each instantaneous date is compared with the reference datum and, if deviated, by more than one predefined or specifiable threshold value an action is triggered.

Claims

claims

1. A method for monitoring a device involved in a production process, in particular a packaging machine, with at least one drive (10), characterized in that during operation of the drive (10) at least once drive-related reference data (24) are recorded and at least one reference datum is stored in relation to this data (24), that drive-related data (26) are recorded continuously or at predefined or specifiable times and at least one instantaneous datum is derived therefrom and that the or each current datum is compared with the reference datum and in case of deviation by more than a predetermined or predefinable threshold, an action is triggered.

2. Monitoring method according to claim 1, wherein the drive (10) is associated with a rotary encoder (28) and the drive-related reference data (24) and the drive-related data (26) result from an output signal supplied from the rotary encoder (28).

3. Monitoring method according to claim 1 or 2, wherein the drive-related reference data (24) are included in production breaks, in particular by a reference run is performed during the production break.

4. Monitoring method according to claim 1 or 2, wherein the drive-related reference data (24) are recorded during the production process by predetermined or predetermined characteristic movement phases for recording the reference data (24) are used.

5. Monitoring method according to one of claims 2 to 4, wherein as the drive-related reference data (24) or data (26) via the rotary encoder (28) determined acceleration of the drive (10) is used.

6. Monitoring method according to claim 5, wherein a standard deviation, an autocorrelation, a characteristic frequency or a characteristic frequency range of the drive-related reference data (24) or the drive-related data (26) is determined as reference date and instantaneous date.

A computer program comprising computer executable program code instructions for implementing the method of any one of claims 1 to 6 when the computer program is run on a computer.

8. Computer program product, in particular storage medium, with a computer-executable computer program according to claim 7.

9. Monitoring device with means for carrying out the method according to one of claims 1 to 6, in particular with a processing unit and a computer program product executable by the processing unit according to claim 8.