Abstract
In an operating method for a transmission having a plurality of transmission components, an operating state of the transmission is established and a mechanical stress on a first transmission component is detected. An amount of damage to the first transmission component then determined based on the detected mechanical stress for a first damage mechanism and added to a defect total using a first defect accumulation model. A model-based remaining useful life of the first transmission component and a probability of occurrence are determined based on the first defect accumulation model. The probability of occurrence for the model-based remaining useful life is determined based on data sets of comparison components having an identical construction to the first transmission component. A corresponding computer program product, a control unit, a monitoring system and a transmission application operating according to the method are also described.
Claims
1.-17. (canceled)
18. A method for operating a transmission haying a plurality of transmission components, comprising: establishing an operating state of the transmission and measuring a mechanical stress on a first transmission component; determining an amount of damage to the first transmission component based on the measured mechanical stress for a first damage mechanism and a second damage mechanism; in a first defect accumulation model of the first damage mechanism and the second damage mechanism, adding the determined amount of damage for the first damage mechanism and the second damage mechanism to a defect total; determining a model-based remaining useful life of the first transmission component based on the first defect accumulation model and determining a probability of occurrence for the model-based remaining useful life based on data from comparison transmission components having an identical construction as the first transmission component and being employed in other transmissions; storing in a data set at least one of the measured mechanical stress, the amount of damage, the defect total, the model-based remaining useful life, and the probability of occurrence; and employing the data set as a comparison data set for other transmission components having the identical construction as the first transmission component.
19. The method of claim 18, further comprising outputting a warning when the model-based remaining useful life falls below a configurable first threshold value or the probability of occurrence falls below a configurable second threshold value.
20. The method of claim 18, further comprising determining a mechanical stress on a second transmission component based on the measured mechanical stress on the first transmission component by using a transfer function, adding the determined amount of damage for the first damage mechanism and the second damage mechanism to the defect total, and determining the model-based remaining useful life based on the first defect accumulation model and determining the probability of occurrence for the model-based remaining useful life also for the second transmission component.
21. The method of the claim 18, wherein the first or second damage mechanism comprise a feature selected from high-cycle fatigue, low cycle fatigue, wear, tooth root breakage and pitting at a toothed gearing.
22. The method of claim 18, wherein the probability of occurrence for the model-based remaining useful life is determined based on a distribution function of permitted defect totals of the comparison components.
23. The method of claim 18, wherein the defect total can be set by using an algorithm or a user input.
24. The method of claim 18, further comprising determining, based on the model-based remaining useful life or the probability of occurrence, an anticipated repair cost for the first transmission component or for the transmission.
25. The method of claim 24, further comprising providing inventory instructions to a materials management system for at least the first transmission component.
26. The method of claim 18, further comprising determining the model-based remaining useful life or the probability of occurrence based on a configurable load level for continued operation of the first transmission component.
27. A computer program product for operating a transmission, comprising a first part-program embodied in a non-transitory computer readable medium and being either entirely or at least partially in a data connection with a second part-program, wherein the first and second part programs, when loaded into a storage entity of a control unit and executed by the control unit, cause the control unit to perform the steps of establishing an operating state of the transmission and measuring a mechanical stress on a first transmission component, determining an amount of damage to the first transmission component based on the measured mechanical stress for a first damage mechanism and a second damage mechanism, in a first defect accumulation model of the first damage mechanism and the second damage mechanism, adding the determined amount of damage for the first damage mechanism and the second damage mechanism to a defect total, determining a model-based remaining useful life of the first transmission component based on the first defect accumulation model and determining a probability of occurrence for the model-based remaining useful life based on data from comparison transmission components having an identical construction as the first transmission component and being employed in other transmissions, storing in a data set at least one of the measured mechanical stress, the amount of damage, the defect total, the model-based remaining useful life, and the probability of occurrence, and employing the data set as a comparison data set for other transmission components having the identical construction as the first transmission component.
28. A control unit for controlling a transmission, said control unit comprising: a storage entity, and a computing unit configured to execute a computer program having program instructions stored on a non-transitory computer-readable storage medium, with the program instructions comprising at least one part-program which operates either entirely or at least partially in data connection with a second part-program, wherein the program instructions, when stored in the storage entity and executed by the computing unit, cause the control unit to perform the steps of establishing an operating state of the transmission and measuring a mechanical stress on a first transmission component, determining an amount of damage to the first transmission component based on the measured mechanical stress for a first damage mechanism and a second damage mechanism, in a first defect accumulation model of the first damage mechanism and the second damage mechanism, adding the determined amount of damage for the first damage mechanism and the second damage mechanism to a defect total, determining a model-based remaining useful life of the first transmission component based on the first defect accumulation model and determining a probability of occurrence for the model-based remaining useful life based on data from comparison transmission components having an identical construction as the first transmission component and being employed in other transmissions, storing in a data set at least one of the measured mechanical stress, the amount of damage, the defect total, the model-based remaining useful life, and the probability of occurrence, and employing the data set as a comparison data set for other transmission components having the identical construction as the first transmission component.
29. The control unit of claim 28, wherein the control unit is arranged at the transmission as an internal control unit or is installed separately from the transmission as a supervisory control unit.
30. A monitoring system for a transmission coupled with at least one first transmission component to be monitored, comprising a plurality of sensors for detecting measured data that corresponds to a mechanical stress on the first transmission component, and a control unit connected to the plurality of sensors and designed as an internal control unit or as a supervisory control unit, said control unit being designed as set forth in claim 28.
31. A transmission, comprising a plurality of first and second transmission components, wherein at least one first transmission component is coupled to at least one sensor associated with a monitoring system, with the monitoring system designed as set forth in claim 30.
32. A transmission application, comprising a transmission arranged between a drive unit and a driven unit and configured to change a rotational speed, said transmission application being embodied as an industrial application, a wind turbine, a and vehicle, a watercraft or an aircraft, with the transmission is designed as set forth in claim 31.
Description
[0025] The invention is described below with reference to individual embodiment variants. The features of the individual embodiment variants can be combined with each other in this case. The figures are mutually complementary to the extent that the same reference characters in the figures also have the same technical significance, wherein:
[0026] FIG. 1 shows a schematic structure of a first embodiment variant of the claimed transmission;
[0027] FIG. 2 shows a schematic execution of a first embodiment variant of the claimed method;
[0028] FIG. 3 shows a diagram of a step of the claimed method;
[0029] FIG. 4 shows a schematic execution of a second embodiment variant of the claimed method;
[0030] FIG. 5 shows a schematic execution of a third embodiment variant of the claimed method;
[0031] FIG. 6 shows a schematic structure of a claimed monitoring system;
[0032] FIG. 7 shows a schematic structure of a claimed transmission application.
[0033] FIG. 1 schematically shows a structure of a first embodiment variant of a claimed transmission 10, including sensors 22 and a control unit 40 in the form of an internal control unit 42, by means of which the claimed method 100 is implemented. The transmission 10 comprises a housing 11, in or on which are arranged a plurality of transmission components 12. The transmission components 12 take the form of gearwheels 14, shafts 16 and bearings 18. Without restricting the general applicability of the invention, the transmission 10 is designed as a spur gear transmission in FIG. 1. The gearwheels 14 are mounted on the shafts 16, which in turn are rotatably mounted in bearings 18. The bearings 18 are secured to the housing 11. Each of the transmission components 12, i.e. each gearwheel 14, each shaft 16 and each bearing 18, is provided with a sensor 22 which is suitable for indirectly or directly detecting a mechanical stress 25 on the corresponding transmission component 12 during operation of the transmission 10. To this end, the sensors 22 are designed as strain gauges, force transducers, temperature sensors, rotational speed sensors, surface acoustic wave (SAW) sensors, cameras, or a combination of these. Direct detection of a mechanical stress 25 is understood to mean e.g. detecting a strain at a surface of a shaft 16 by means of a strain gauge or a SAW sensor. Indirect detection of a mechanical stress 25 is understood to mean e.g. detecting a temperature of a bearing 18, wherein a thermal strain state of the bearing can be ascertained by means of a corresponding model on the basis of the detected temperature. The sensors 22 are designed to correspondingly generate measured data 27 which is transferred to a control unit 40. In the case of indirect detection of the mechanical stress 25 on a transmission component 12, the mechanical stress 25 can be ascertained by at least one of the control units 40 from the received measured data 27.
[0034] The internal control unit 42 is connected to a further control unit 40, which is designed as a supervisory control unit 44. The control units 40 are communicatively linked to each other via a data connection 45. A computer program product 80 is executably stored in non-volatile form on both control units 40 and is also executed during the operation of the transmission 10. The computer program products 80 are suitable for processing the received measured data 27 and are designed to implement the inventive method 100 at the transmission 10 by means of the measured data 27. It is also possible via the data connection 45 to exchange parameters 73, by means of which the execution of the method 100 is influenced, between the internal control unit 42 and the supervisory control unit 44. The parameters 73 which are used in the internal control unit 42 for the execution of the method 100 can therefore be configured in respect of type and value by the supervisory control unit 44 as specifications 77. Specifications 77 for the method 100 that are specified by an algorithm 79 can likewise be exchanged between the supervisory control unit 44 and the internal control unit 42. In this case, such an algorithm 79 can be executed on the internal control unit 42 and the supervisory control unit 44. The specifications 77 can also be generated by means of a user input 78 which takes place at the supervisory control unit 44. The supervisory control unit 44 is also communicatively linked to a database 60 via a data connection 45. In the database 60 are stored data sets 64 of comparison components 62, which can also be forwarded to the internal control unit 42 as parameters 73. The data sets 64 of the comparison components 62 are used as comparison values for the purpose of performing the inventive method 100. These are comparison components 62 which have a largely identical construction to the corresponding transmission component 12 that is to be monitored by the method 100. The supervisory control unit 44 is also communicatively connected to a materials management system 68 via a data connection 45. The supervisory control unit 44 is designed to output a stock level statement 66 to the materials management system 68 in order thus to allow a corresponding spare part to be reserved or procured in the event of an impending failure of a transmission component 12, for example. The supervisory control unit 44 is equally suitable for outputting a warning 65 to a user if the method 100 ascertains that a failure of a transmission component 12 is imminent.
[0035] FIG. 1 illustrates the transmission 10 in an operating state 20 in which a first method step 110 is performed. Driving power 21 is supplied which, allowing for mechanical losses, is then output by the transmission 10 as output power 23. As a result of the driving power 21, mechanical stresses 25 that are detected by the sensors 22 occur in the transmission components 12. The operating state 20 from which the method 100 starts in the first method step 110 is understood to be an operating state in which measured data 27 that is useful in the context of the method 100 is generated by the sensors 22. In this case, the operating state 20 can be a steady operating state or a transient event, e.g. an acceleration.
[0036] FIG. 2 schematically illustrates a further execution of an embodiment variant of the claimed method 100 which is executed at a transmission component 12 as shown in FIG. 1. In this case, the transmission component 12 is a shaft 18 which is linked to a sensor 22. The transmission component 12, i.e. the shaft 18, is subjected to a torsional load 26 during an operating state 20 that is present in a first method step 110. As a result of the torsional load 26, a mechanical stress 25 on the shaft 18 is produced, and captured in the form of measured data 27 and sent to a processing unit 49 of the control unit 40. By means of the processing unit 49, which can be assigned individually or modularly to the internal and/or the supervisory control unit 42, 44, an amount of damage 35 is ascertained in a second method step 120. The amount of damage 35 corresponds in this case to a damage of the monitored transmission component 12, i.e. the shaft 18, which was caused by the detected mechanical stress 25. The ascertainment of the amount of damage 35 takes place in the context of a respective defect accumulation model 30, which can be configured for the transmission component 12.
[0037] The defect accumulation model 30 for the corresponding transmission component 12 is illustrated in FIG. 2 by the left-hand diagram. It comprises a horizontal load-cycle-alternation axis 31 and a vertical intensity axis 32 for relevant load cycles. The defect accumulation model 30 also has model limit lines 33, each of which is assigned to a first or second damage mechanism 38, 39. The model limit lines 33 specify in each case the defect total 43 that is assumed by the defect accumulation model 30 to signify a failure of the transmission component 12 as a result of the corresponding damage mechanism 38, 39. This can be e.g. LCF and HCF, wear, tooth root breakage or pitting at a toothed gearing. In a third method step 130, the amount of damage 35 that is ascertained in the second method step 120 and occurs in the operating state 20 is added in the current defect accumulation model 30 to an existing defect total 43 in a defect group 34. As shown in FIG. 1, the defect total 43 is an aggregation of damages in individual defect groups 34 of different intensity. In a fourth method step 140 following thereupon, the model remaining useful life 36 of the transmission component 12 is ascertained for a configurable load level 29. This ascertainment of the model remaining useful life 36 is also illustrated in FIG. 2 by the arrows 48, whose lengths extend from a block of the corresponding defect group 34, this corresponding to the load level 29, to the model limit line 33 of the first or second damage mechanism 38, 39. Corresponding model total useful lives 41 of the transmission component 12 are then derived from the corresponding model remaining useful lives 36 for the first and second damage mechanisms 38, 39 respectively.
[0038] On the basis of the model remaining useful lives 36 for the first and second damage mechanism 38, 39, and therefore the model total useful lives 41 of the transmission component 12, the occurrence probabilities 57 that the transmission component 12 will actually achieve the corresponding model total useful life 41 are ascertained. This is illustrated in FIG. 2 in the right-hand distribution diagram 50, which comprises a horizontal useful life axis 53 and a vertical frequency axis 52. The diagram also features a curve of a distribution function 51 that indicates the frequency with which a specific defect total 43 is reached during operation in the case of comparison components 62 having an identical construction to the transmission component 12. In the fourth method step 140, a vertical line 47 in the distribution diagram 50 specifies which model total useful life 41 is required by the transmission component 12 in the case of a first or second damage mechanism 38, 39 and a previously ascertained model remaining useful life 36. This results in a survival region 55 and a failure region 54 in the distribution diagram 50 for each of the damage mechanisms 38, 39. The respective area under the distribution function 51 in the corresponding survival region 55 corresponds to an occurrence probability 57 with which the transmission component 12 will surpass a required model remaining useful life 36 for the respective damage mechanism 38, 39. It is consequently possible to establish the probability with which the transmission component 12 will also achieve the required model remaining useful life 36. The distribution function 51 is specified by a plurality of data sets 64 of comparison components 62 which are stored in a database 60. The data sets 64 are continuously updated by means of a multiplicity of comparison components 62, so that experiences of users of identically constructed comparison components 62 can be used for the transmission component 12. By means of a distribution function 51 which is updated in this way, it is possible inter glia to make use of unexpectedly long useful lives, i.e. unexpectedly high defect totals 43 before failure, of transmission components 12 during operation. Conversely, surprisingly short useful lives, i.e. low defect totals 43 before failure, can be taken into consideration. By means of continuously updating the distribution function 51 using comparison components 62, a dynamic monitoring system 90 is realized which becomes more reliable and precise in the prediction of failures of transmission components 12 as the duration of operation increases.
[0039] FIG. 3 schematically shows a further aspect of the fifth method step 150 of the claimed method 100. In particular, the evaluation diagram 70 shown in FIG. 3 represents a warning or response characteristic of the method 100. The evaluation diagram 70 comprises a horizontal time axis 71 and a vertical magnitude axis 72 relative to which a model remaining useful life 36 and an occurrence probability 57 are indicated. Both variables are shown in FIG. 4 for the first damage mechanism 38 and relate to a transmission component 12 which can take the form of a gearwheel 14, a shaft 16 or a bearing 18. Furthermore, the transmission component 12 is subjected to a specifiable load level 29 along the time axis 71. The model remaining useful life 36 and the occurrence probability 57 decease along the time axis 71. A configurable first threshold value 75 is also defined for the model remaining useful life 36. If the model remaining useful life 36 fails below the first threshold value 75, a warning 65 and/or a stock level statement 66 is triggered. As a result of this, a user is warned or the provision of a spare part is initiated in advance of an impending failure of the transmission component 12. In a similar manner, a configurable second threshold value 76 is specified for the occurrence probability 57. If the occurrence probability 57 falls below the second threshold value 76, a warning 65 and/or a stock level statement 66 is likewise output for the transmission component 12. The first and second threshold values 75, 76 belong to the parameters 73 which, as illustrated in FIG. 1, influence the execution of the method 100 and can be specified by a user input 78 or an algorithm 79.
[0040] FIG. 4 schematically shows the execution of a second embodiment variant of the claimed method 100. The method 100 starts from a first method step 110, in which the transmission 10 with the plurality of transmission components 12 is provided, wherein at least one first transmission component 12 is to be monitored. In this case, the transmission 10 is in an operating state 20 in which a mechanical stress 25 on the first transmission component 12 is ascertained using a sensor 22. This is followed by a second method step 120 in which, on the basis of the mechanical stress 25, an amount of damage 35 is ascertained more correspondingly in the context of a configurable defect accumulation model 30 and a configurable first damage mechanism 38. In a third method step 130 following thereupon, the amount of damage 35 is added to a defect total 43 in the defect accumulation model 30 for the first damage mechanism 38. In a subsequent fourth method step 140, a model remaining useful life 36 is ascertained for the first damage mechanism 38 in the context of the defect accumulation model 30. An occurrence probability 57 for the corresponding model remaining useful life 36 is likewise ascertained in the fourth method step 140. In this case, the ascertainment of the model remaining useful life 36 and occurrence probability 57 thereof is based on a configurable load level 29 corresponding to an expected or intended future operation of the transmission component 12 and hence of the transmission 10. The occurrence probability 57 in this case is ascertained with reference to data sets 64 of comparison components 62, by means of which a distribution function 51 of useful lives is established. A sixth method step 160 takes place in parallel with the fourth method step 140 and, on the basis of the model remaining useful life 36 and the occurrence probability 57, performs a cost forecast 67 for a maintenance job for the first transmission component 12. A result of the cost forecast 67 can be displayed to a user. The fourth method step 140 is followed by a first branch point 145, at which the model remaining useful life 36 and/or the occurrence probability 57 from the fourth method step 140 are compared with configurable parameters 73. The configurable parameters 73 also comprise a first and a second threshold value 75, 76 for the model remaining useful life 36 and the occurrence probability 57 respectively. If the threshold values 75, 76 are exceeded, it is confirmed that no operating state is present which requires a response, and the method 100 returns to the first method step 110 via a return loop 170. If the model remaining useful life 36 or the occurrence probability 57 falls below the first and/or second threshold value 75, 76, a fifth method step 150 is performed. In said fifth method step 150, a warning 65 is output and/or a stock level statement 66 for the first transmission component 12 is output. The method 100 finally arrives at an end state 200. The method 100 according to FIG. 4 executes entirely or in a functionally distributed manner in one or a plurality of computer program products 80 which are stored in a non-volatile and executable manner on a control unit 40. The control unit 40 in this case comprises an internal control unit 42 and/or a supervisory control unit 44.
[0041] FIG. 5 shows a schematic execution of a third embodiment variant of the claimed method 100. The method 100 starts from a first method step 110, in which a mechanical stress 25 on a first transmission component 12.1 in an operating state 20 is ascertained by means of a sensor 22. With the aid of a transfer function 83, a mechanical stress 25 on a second transmission component 12.2 in the same operating state 20 is ascertained therefrom. The first and second transmission components 12.1 and 12.2 belong to the same transmission 10. A transfer function 83 is understood to be a physical relationship between the first and second transmission components 12.1, 12.2, which relationship describes a mechanical stress 25 on the first transmission component 12.1 as essentially a function of the mechanical stress 25 on the second transmission component 12.2. Such a transfer function 83 can take the form of a value table, an algorithm 79 or a simulation. On the basis of the mechanical stress 25 on the second transmission component 12.2, the second, third, fourth, fifth and sixth method steps 120, 130, 140, 150, 160 are performed in a similar manner to FIG. 4.
[0042] The first method step 110 is followed by a second method step 120 in which, on the basis of the mechanical stress 25, an amount of damage 35 ascertained more correspondingly in the context of a configurable defect accumulation model 30 and a configurable first damage mechanism 38. In a third method step 130 following thereupon, the amount of damage 35 is added to a defect total 43 in the defect accumulation model 30 for the first damage mechanism 38. In a subsequent fourth method step 140, a model remaining useful life 36 is ascertained for the first damage mechanism 38 in the context of the defect accumulation model 30. An occurrence probability 57 for the correspond model remaining useful life 36 is likewise ascertained in the fourth method step 140. In this case, the ascertainment of the model remaining useful life 36 and occurrence probability 57 thereof is based on a configurable load level 29 corresponding to an expected or intended future operation of the second transmission component 12.2 and hence of the transmission 10. The occurrence probability 57 in this case is ascertained with reference to data sets 64 of comparison components 62, by means of which a distribution function 51 of useful lives is established. A sixth method step 160 takes place in parallel with the fourth method step 140 and, on the basis of the model remaining useful life 36 and the occurrence probability 57, performs a cost forecast 67 for a maintenance job for the second transmission component 12.2. A result of the cost forecast 67 can be displayed to a user. The fourth method step 140 is followed by a first branch point 145, at which the model remaining useful life 36 and/or the occurrence probability 57 from the fourth method step 140 are compared with configurable parameters 73. The configurable parameters 73 also comprise a first and a second threshold value 75, 76 for the model remaining useful life 36 and the occurrence probability 57 respectively. If the threshold values 75, 76 are exceeded, it is confirmed that no operating state is present which requires a response, and the method 100 returns to the first method step 110 via a return loop 170. If the model remaining useful life 36 or the occurrence probability 57 falls below the first and/or second threshold value 75, 76, a fifth method step 150 is performed. In said fifth method step 150, a warning 65 is output and/or a stock level statement 66 for the second transmission component 12.2 is output. The method 100 finally arrives at an end state 200. The method 100 according to FIG. 5 executes entirely or in a functionally distributed manner in one or a plurality of computer program products 80 which are stored in a non-volatile and executable manner on a control unit 40. The control unit 40 in this case comprises an internal control unit 42 and/or a supervisory control unit 44.
[0043] The structure of a first embodiment variant of the claimed monitoring system 90 is depicted in FIG. 6. The monitoring system 90 comprises a plurality of sensors 22 which are designed to indirectly or directly detect a mechanical stress 25 on a transmission component 12 of a transmission 10. In order to achieve this, measured data 27 is transferred from the sensors 22 to a control unit 40 which comprises an internal control unit 42. A computer program product 80 is executably stored in non-volatile form in a storage entity of the internal control unit 42. The internal control unit 42 is designed to receive the measured data 27 from the sensors 22 and process it by means of the computer program product 80. The computer program product 80 has a first part-program 82, which is executably stored in a non-volatile manner on the first control unit 42. The claimed method 100 is partially implemented by the first part-program 82 in at least one embodiment variant. The first part-program 82 is communicatively linked to a supervisory control unit 44 via a data connection 45. Furthermore, a second part-program 84 is executably stored in a non-volatile manner on the supervisory control unit 44, and belongs to the same computer program product 80 as the first part-program 82. Using the communicative data connection 45 between the internal and the supervisory control unit 42, 44, communication takes place between the first and second part-programs 82, 84. The second part-program 84 partially implements the claimed method 100. By means of the communicative data connection 45, the first and second part-programs 82, 84 work together to fully realize the claimed method 100. To this end, the first and second part-programs 82, 84 exchange parameters 73, values from specifications 77 and/or values from algorithms 79.
[0044] FIG. 7 schematically shows the structure of a claimed transmission application 95 comprising a drive unit 96, a driven unit 97 and a transmission 10. The transmission 10 is attached between the drive unit 96 and the driven unit 97. By means of the transmission 10, a driving power 21 is transferred from the drive unit 96 to the driven unit 97 as output power 23, and changed in terms of rotational speed and torque. The transmission application 95 in this case can take the form of an industrial application, a wind turbine, a land vehicle, a watercraft or an aircraft.
