SOFTWARE BASED CONDITION MONITORING FOR MACHINES

Abstract

A computer-implemented method of predicting conditions of machines as well as a corresponding data processing system, computer program and computer-readable medium are disclosed. A technical specification of a machine is received. A data set including at least one current operational parameter of the machine is continuously received. A current load of the machine is continuously derived based on the provided technical specification and the received data set via a knowledge base. A current condition of the machine is continuously predicted by integrating over the derived current load and all previously derived current loads.

Claims

1.-14. (canceled)

15. A computer-implemented method for determining conditions of electric motors, the method comprising: receiving a technical specification of an electric motor comprising at least maximal torque and/or maximal rotational speed of an electric motor; continuously receiving from a frequency converter of the electric motor, a data set including at least electrical current currently supplied to the electric motor by the frequency converter; continuously deriving a current load of the electric motor based on the technical specification and the data set via a knowledge base, wherein the knowledge base comprises relationships between the technical specification together with the data set and the current load of the electric motor, wherein deriving the current load comprises deriving a current electrical torque of the electrical motor by the frequency converter, and based on the derived current electrical torque, deriving the current load of the electric motor via the knowledge base; continuously determining a current condition of the electric motor by integrating over the derived current load and all previously derived current loads; and deriving and updating a time point for servicing of the electric motor based on the current condition of the electric motor.

16. The computer-implemented method of claim 15, wherein the electric motor is a geared electric motor.

17. The computer-implemented method of claim 15, wherein the knowledge base is implemented in a cloud system, and the cloud system is communicatively connected with a controller or connector, the controller or connector communicatively connected with the electric motor, or alternatively, the cloud system is communicatively connected with the electric motor.

18. The computer-implemented method of claim 17, wherein the controller or connector is communicatively connected with the frequency converter of the electric motor.

19. The computer-implemented method of claim 17, wherein the cloud system is communicatively connected with the frequency converter of the electric motor.

20. The computer-implemented method of claim 15, wherein the knowledge base is implemented in a controller communicatively connected with the electric motor.

21. The computer-implemented method of claim 20, wherein the controller is communicatively connected with the frequency converter of the electric motor.

22. The computer-implemented method of claim 15, wherein the knowledge base is implemented in the electric motor.

23. The computer-implemented method of claim 22, wherein the knowledge base is implemented in the frequency converter of the electric motor.

24. The computer-implemented method of claim 15, wherein continuously deriving the current load of the electric motor comprises deriving a current load of at least two different components of the electric motor, and wherein continuously determining a current condition comprises predicting current conditions of the at least two different components of the electric motor.

25. The computer-implemented method of claim 24, wherein deriving a time point for servicing comprises deriving time points for servicing of the at least two different components of the electric motor each based on the respective predicted current condition of the respective component.

26. A data processing system for predicting conditions of electric motors, the data processing system comprising means for carrying out a computers-implemented method as set forth in claim 15.

27. The data processing system of claim 26, wherein the knowledge base is implemented in a cloud system, and the cloud system is communicatively connected with a controller or connector, the controller or connector communicatively connected with the electric motor, or alternatively, the cloud system is communicatively connected with the electric motor.

28. The data processing system of claim 27, wherein the controller or connector is communicatively connected with the frequency converter of the electric motor.

28. The data processing system of claim 27, wherein the cloud system is communicatively connected with the frequency converter of the electric motor.

30. The data processing system of claim 26, wherein the knowledge base is implemented in a controller communicatively connected with the electric motor.

31. The data processing system of claim 30, wherein the controller is communicatively connected with the frequency converter of the electric motor.

32. The data processing system of claim 26, wherein the knowledge base is implemented in the electric motor.

33. The data processing system of claim 32, wherein the knowledge base is implemented in the frequency converter of the electric motor.

34. A computer program embodied in a non-transitory computer readable medium comprising instructions which, when the computer program is executed by a computer, cause the computer to carry out the steps of the method of claim 15.

35. A computer-readable medium having stored thereon the computer program of claim 33.

Description

[0053] The present invention and its technical field are subsequently explained in further detail by exemplary embodiments shown in the drawings. The exemplary embodiments only conduce better understanding of the present invention and in no case are to be construed as limiting for the scope of the present invention. Particularly, it is possible to extract aspects of the subject-matter described in the figures and to combine it with other components and findings of the present description or figures, if not explicitly described differently. Equal reference signs refer to the same objects, such that explanations from other figures may be supplementarily used.

[0054] FIG. 1 shows a schematic flow-chart of an embodiment of the computer-implemented method of predicting conditions of machines and of the corresponding computer program.

[0055] FIG. 2 shows a schematic view of an embodiment of the electric geared motor.

[0056] FIG. 3 shows a schematic view of an embodiment of the controller and the electric geared motor.

[0057] FIG. 4 shows a schematic view of another embodiment of the controller and the electric geared motor.

[0058] FIG. 5 shows a schematic view of an embodiment of the cloud system, controllers and electric geared motors.

[0059] FIG. 6 shows a schematic view of an embodiment the data processing system for predicting conditions of machines.

[0060] FIG. 7 shows a schematic view of an embodiment of the computer-readable medium.

[0061] FIG. 8 shows an exemplary graph of a statically calculated current condition and time point for servicing and a dynamically calculated current condition and time point for servicing of the machine.

[0062] In FIG. 1 a possible embodiment of the computer-implemented method of predicting conditions of machines according to the first aspect of the present invention and of the corresponding computer program according to the third aspect of the present invention are schematically depicted.

[0063] The computer-implemented method comprises the steps of receiving S1 a technical specification TS, continuously receiving S2 a data set DS.sub.i, continuously deriving S3 a current load CL.sub.i, continuously predicting S4 a current condition CC.sub.i and deriving S5 a time point T.sub.s.

[0064] In the step of receiving S1 a technical specification TS of a machine, here exemplarily an electric geared motor 10 (see FIGS. 2 to 5) is received. The technical specification TS includes values of quantities and references describing the machine. In particular, the technical specification TS may include: a type of the motor, an installation size of the motor, a number of poles, a maximal power of the motor, a maximal torque of the motor, a maximal rotational speed of the motor, a type of the gearbox, an amount of gears, an installation size of the gearbox, a transmission ratio, a type of the drive shaft, a size/diameter of the drive shaft, a maximal load torque, a maximal load rotational speed, a maximal radial force, a drive direction (forward, backward, both), a type of the lubricating oil (for the gearbox or motor), type of oil cooling (air flow, water, none), an (average, minimal, maximal) ambient temperature, a type of bearing (for the motor or the gearbox), a type of gasket, outer mass moments of inertia, and the like.

[0065] The continuously executed steps S2 to S4 and optionally S5 are executed with a predefined clock (sampling) rate. In other words, at every equidistant time point (sampling instance) T.sub.i of the clock rate, the steps are executed.

[0066] In the step of continuously receiving S2 a data set DS.sub.i, a current data set DS.sub.i is received from the machine 10, here, from a frequency converter 5 (see FIGS. 2 to 5) of the machine 10. Each current data set DS.sub.i at the time point T.sub.i includes at least one current operational parameter OP.sub.i of the machine 10. In particular, each current data set DS.sub.i may include a current electric power, a current electric current, and additionally or alternatively a current voltage supplied to drive the machine.

[0067] In the step of continuously deriving S3 a current load CL.sub.i, current load CL.sub.i of critical components 1, 2, 3, 4 (see FIGS. 2 to 5) of the machine 10 is derived from the provided technical specification TS and from the received current data set (DS.sub.i) via a knowledge base KB. The current load CL.sub.i comprises a quantification of wear of the machine 10 or rather of each of its critical components 1, 2, 3, 4 due to the current operational state and values of physical quantities present in or at the machine or the critical components 1, 2, 3, 4 in the current operational state (e.g. current torque, current rotational speed, current temperature, current vibrations, etc.). In particular, the current load CL.sub.i includes or rather is dependent on a current torque of the machine (motor) 10 that may be derived by the frequency converter 5 or the knowledgebase KB from the current electric current/voltage supplied to the machine 10. Further, the current load CL.sub.i may include or rather be dependent on: a current power of the motor, a current torque of the motor, a current rotational speed of the motor, a current radial force, a current drive direction (forward, backward), mass moments of inertia of components (electric machine, break, gearbox, etc.) of the machine, a mass acceleration factor, an impact level and the like which may be derived by the frequency converter 5 or the knowledgebase KB. For example, the mass acceleration factor may be calculated as:

[00001]$m_{\mathrm{BF}}=\frac{\mathrm{outer}\mathrm{mass}\mathrm{moments}\mathrm{of}\mathrm{inertia}}{\mathrm{mass}\mathrm{moments}\mathrm{of}\mathrm{inertia}\mathrm{of}\mathrm{components}}$

and the impact level may be determined as:

m.sub.BF≤0,3.fwdarw.impact level I

m.sub.BF≤3.fwdarw.impact level II

m.sub.BF≤10.fwdarw.impact level III.

[0068] In the step of continuously predicting S4 a current condition CC.sub.i, current conditions CC.sup.x.sub.i of the critical components 1, 2, 3, 4 of the machine 10 are predicted, The current conditions CC.sub.i are predicted by integrating over the derived current load CL.sub.i and all previously derived current loads CL.sub.i−1 . . . CL.sub.i−N. The current conditions CC.sup.x.sub.i of the critical components 1, 2, 3, 4 determined by continuously summing up all the derived current loads CL.sub.i . . . CL.sub.i−N of the machine 10, each multiplied by the predefined interval between two time points T.sub.i, T.sub.i+1 of the clock rate. In other words, the current conditions CC.sup.x.sub.i of the critical components 1, 2, 3, 4 are the summarised wear of the critical components 1, 2, 3, 4. In particular, the “weakest link of the chain”, which is important to determine the part/critical component 1, 2, 3, 4, of the machine 10 that will fail first, can thus be identified based on the respective determined current conditions CC.sup.x.sub.i of the critical components 1, 2, 3, 4.

[0069] The step of deriving S5 a time point T.sub.s may be executed with the predefined clock rate, with another predefined dock rate (e.g. once a week), or at predefined events (e.g. upon request of a user, etc.).

[0070] In the step of deriving S5 a time point T.sub.s, time points T.sup.x.sub.s for servicing of the critical components 1, 2, 3, 4 of the machine 10 are derived each based on the respective predicted current condition CC.sup.x.sub.i of the respective component 1, 2, 3, 4. The predicted current conditions CC.sup.x.sub.i may be compared to predefined service conditions of the critical components 1, 2, 3, 4 of the machine 10, which predefined service conditions give the conditions of the critical components at which they need servicing or replacement. Based on the difference between the predicted current conditions CC.sup.x.sub.i and the predefined service conditions the time points T.sup.x.sub.s for servicing may be projected based on a mean load of the machine 10 which may be determined from the current and all previous derived current loads CL.sub.i . . . CL.sub.i−N of the machine 10.

[0071] In FIG. 2 an embodiment of an electric geared motor 10 is schematically depicted.

[0072] The electric geared motor 10 is a possible type of machine for which the current conditions CC.sup.x.sub.i and time points for servicing T.sup.x.sub.x of its critical components can be predicted with the method according to FIG. 1. The electric geared motor 10 comprises the following critical components: an electric machine 1, a gearbox 2, bearings 3 and a brake 4. The electric geared motor 10 further comprises a frequency converter 5.

[0073] The electric machine 1 is electrically connected with the frequency converter 5 and driven by an electrical power supplied to the electric machine 1 by the frequency converter 5.

[0074] The gearbox 2 is mechanically connected to the electric machine 1 and transmits the torque generated by the electric machine 1 into a drive torque at a drive shaft of the electric geared motor 10.

[0075] The bearings 3 pivot the pivotable elements of the electric machine 1 and the gearbox 2 in their respective housings.

[0076] The brake 4 is mechanically connected with the electric machine 1 and additionally or alternatively with the gearbox and decelerates the pivotable elements upon actuation.

[0077] The frequency converter 5 is electrically connected to an electrical power source (not depicted) and to a controller 20 (see FIGS. 3 to 5). The frequency converter 5 adapts the electrical power of the electrical power source according to control commands of the controller 20 and provides the adapted electrical power to the electric machine 1.

[0078] The frequency converter 5 comprises a data processing system 40 (see FIG. 6) like a computer and is configured to execute the method according to FIG. 1.

[0079] In FIG. 3 an embodiment of the controller 20 and the electric geared motor 10 is schematically depicted. The electric geared motor 10 corresponds to the electric geared motor according to FIG. 2, except its frequency converter 5 which is here not configured to execute the method according to FIG. 1.

[0080] The controller 20 is here a programmable logic controller PLC 21 and communicatively connected to the frequency converter 5 of the electric geared motor 10. The PLC 21 may be communicatively connected to several machines like electric geared motors 10. The PLC 21 provides control commands to the frequency converter 5 for controlling the drive torque of the electric geared motor 10 (and may further provide control commands to several other machines).

[0081] The controller 20/PLC 21 comprises a data processing system 40 (see FIG. 6) like a computer and is configured to execute the method according to FIG. 1 (for each of the machines 10 connected to the PLC 21). Thereto, the frequency converter 5 forwards the current data set DS to the PLC 21 at every sampling instance of the predefined clock rate.

[0082] In FIG. 4 another embodiment of the controller 20 and the electric geared motor 10 is schematically depicted. The electric geared motor 10 corresponds to the electric geared motor according to FIG. 3 and the PLCs 21 correspond to the PLC 21 according to FIG. 3, except here they are not configured to execute the method according to FIG. 1.

[0083] The controller 20 is here an industrial edge device 22 and communicatively connected to several, here exemplarily two, PLCs 21 which are each communicatively connected with exemplarily one electric geared motor 10. The industrial edge device 22 provides control commands to the PLCs 21 for controlling the drive torques of the electric geared motors 10 (and several other (not depicted) machines connected to the PLCs 21).

[0084] The controller 20/industrial edge device 22 comprises a data processing system 40 (see FIG. 6) like a computer and is configured to execute the method according to FIG. 1 for each of the electric geared motors 10 (and for the several other machines connected to the PLCs 21). Thereto, the frequency converters 5 forward the current data sets DS to the PLCs 21 which in turn forwards the current data sets DS.sub.i to the industrial edge device 22 at every sampling instance of the predefined clock rate.

[0085] In FIG. 5 an embodiment of the cloud system 30, controllers 20 and electric geared motors 10 is schematically depicted. The electric geared motor 10 corresponds to the electric geared motor according to FIGS. 3 and 4, the PLCs 21 correspond to the PLCs 21 according to FIGS. 3 and 4, except here they are not configured to execute the method according to FIG. 1, and the industrial edge device 22 corresponds to the industrial edge device 22 according to FIG. 4, except here it is not configured to execute the method according to FIG. 1.

[0086] The cloud system 30 is communicatively connected to the industrial edge device 22, which is connected to two of the PLCs 21, and to one of the PLCs 21, which is not connected to the industrial edge device 22. The PLCs 21 are each communicatively connected with exemplarily one electric geared motor 10 (and several other (not depicted) machines). The cloud system 30 may also be communicatively connected to a connector, in particular an IoT gateway (not depicted), which connector is communicatively connected to one or more machines 10 or rather frequency converters 5 of electric (geared) motors 10. Moreover, the cloud system 30 may be directly communicatively connected to one or more machines 10 or rather frequency converters 5 of electric (geared) motors 10 (not depicted).

[0087] The cloud device 30 comprises a data processing system 40 (see FIG. 6) like a computer and is configured to execute the method according to FIG. 1 for each of the electric geared motors 10 (and for the several other machines connected to the PLCs 21). Thereto, the frequency converters 5 forward the current data sets DS.sub.i either directly to the cloud system 30 (not depicted) or to the PLCs 21 and connector (not depicted). The PLCs 21 forward the current data sets DS to the industrial edge device 22, if connected thereto The PLC 21 not connected to the industrial edge device 22, the connector (not depicted), and the industrial edge device 22 forward the current data sets DS.sub.i to the cloud system 30 at every sampling instance of the predefined clock rate.

[0088] In FIG. 6 an embodiment of the data processing system 40 for predicting conditions of machines according to the second aspect of the present invention is schematically depicted.

[0089] The data processing system 40 may be a personal computer (PC), a laptop, a tablet, a server, a distributed system (e.g. cloud system) and the like. The data processing system 40 comprises a central processing unit (CPU) 41 a memory having a random-access memory (RAM) 42 and a non-volatile memory (MEM, e.g. hard disk) 43, a human interface device (HID, e.g. keyboard, mouse, touchscreen etc.) 44, an output device (MON, e.g. monitor, printer, speaker, etc.) 45 and an interlace (I/O) 46 for receiving and sending data. The CPU 41, RAM 42, HID 44 MON 45 and I/O 46 are communicatively connected via a data bus. The RAM 42 and MEM 43 are communicatively connected via another data bus.

[0090] The computer program according to the third aspect of the present invention and schematically depicted in FIG. 1 can be loaded into the RAM 42 from the MEM 43 or another computer-readable medium 50 (see FIG. 7). According to the computer program the CPU executes the steps S1 to S5 of the computer-implemented method according to the first aspect the present invention and schematically depicted in FIG. 1. The execution can be initiated and controlled by a user via the HID 44. The status and/or result of the executed computer program may be indicated to the user by the MON 45 or output via the I/O 46, The result of the executed computer program may be permanently stored on the non-volatile MEM 43 or another computer-readable medium.

[0091] In particular, the CPU 41 and RAM 42 for executing the computer program may comprise several CPUs 41 and several RAMs 42 for example in a computation cluster or a cloud system 30 (see FIG. 5). The HID 34 and MON 35 for controlling execution of the computer program may be comprised by a different data processing system like a terminal communicatively connected to the data processing system 40 (e.g. cloud system 30).

[0092] In FIG. 7 an embodiment of the computer-readable medium 50 according to the fourth aspect of the present invention is schematically depicted.

[0093] Here, exemplarily a computer-readable storage disc 50 like a Compact Disc (CD), Digital Video Disc (DVD), High Definition DVD (HD DVD) or Blu-ray Disc (BD) has stored thereon the computer program according to the third aspect of the present invention and as schematically shown in FIG. 1. However, the computer-readable medium may also be a data storage like a magnetic storage/memory (e.g. magnetic-core memory, magnetic tape, magnetic card, magnet strip, magnet bubble storage, drum storage, hard disc drive, floppy disc or removable storage), an optical storage/memory (e.g. holographic memory, optical tape, Tesa tape, Laserdisc, Phasewriter (Phasewriter Dual, PD) or Ultra Density Optical (UDO)), a magneto-optical storage/memory (e.g. MiniDisc or Magneto-Optical Disk (MO-Disk)), a volatile semiconductor/solid state memory (e.g. Random Access Memory (RAM), Dynamic RAM (DRAM) or Static RAM (SRAM)) or a non-volatile semiconductor/solid state memory (e.g. Read Only Memory (ROM), Programmable ROM (PROM), Erasable PROM (EPROM), Electrically EPROM (EEPROM), Flash-EEPROM (e.g. USB-Stick), Ferroelectric RAM (FRAM), Magnetoresistive RAM (MRAM) or Phase-change RAM).

[0094] In FIG. 8 an exemplary graph of a statically calculated current condition CC.sub.0 (hatched area) and time point T.sub.S,0 for servicing and a dynamically calculated current condition CC.sub.N and time point T.sub.s for servicing of the machine 10 (see FIGS. 2 to 5) is schematically depicted.

[0095] The current condition CC.sub.0 (hatched area) and time point T.sub.S,0 for servicing are statically calculated based on the technical specification TS and one static data set that includes static information about a static operational state of the machine 10.

[0096] In real operation, however, the current load CL.sub.i of the machine 10 varies depending on multiple factors (e.g. level of current utilisation, idle times, etc.). For example, the current load CL.sub.N at time point T.sub.N is lower than the assumed load.

[0097] Consequently, the real wear and the resulting real current condition of the machine 10 differ significantly from the statically calculated values. In particular, the statically calculated time point T.sub.S,0 for servicing is here much earlier than the time point T.sub.S for servicing predicted according to the present invention. Consequently, premature servicing of the machine 10 and accompanying unnecessary consumption of resources can be avoided. Also in the other case, where the real current load CL.sub.i i.e. wear is often higher than statically calculated, too late servicing and possible failure of the machine can be reliably avoided.

[0098] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations exist. It should be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

[0099] In the foregoing detailed description, various features are grouped together in one or more examples for the purpose of streamlining the disclosure. It is understood that the above description is intended to be illustrative, and not restrictive. It is intended to cover all alternatives, modifications and equivalents as may be included within the scope of the invention. Many other examples will be apparent to one skilled in the art upon reviewing the above specification.

[0100] Specific nomenclature used in the foregoing specification is used to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art in light of the specification provided herein that the specific details are not required in order to practice the invention. Thus, the foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed; obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. Throughout the specification, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein,” respectively. Moreover, the terms “first,” “second,” and “third,” etc., are used merely as labels, and are not intended to impose numerical requirements on or to establish a certain ranking of importance of their objects. In the context of the present description and claims the conjunction “or” is to be understood as including (“and/or”) and not exclusive (“either . . . or”).