Method for generating digital twins of a cartesian motion system

Abstract

The invention relates to a method for generating a digital overall model of a Cartesian motion system (10). According to the invention, the associated linear motion system (20; 20a; 20b; 20c) is equipped with a rotary position sensor (25) and a digital nameplate (26), wherein the overall model is generated using individual models of the linear motion system (20; 20a; 20b; 20c) and data of the rotary position sensor (25) and the digital nameplate (26).

Description

TECHNICAL FIELD

[0001] The invention relates to a method for generating a digital overall model of a Cartesian motion system. Such a digital overall model is also referred to as digital twin. BACKGROUND

[0002] A product set of linear motion systems which can be assembled into a Cartesian motion system is known from the catalogue accessible under the address http:www.boschrexroth.com / various / utilities / mediadirectory / download / index.jsp object_nr=R999000044 on October 30, 2019. Each linear longitudinal axis or motion axis of a linear motion system corresponds here preferably to an axis of a corresponding Cartesian coordinate system. With corresponding components, various variants of a Cartesian motion system can be constructed in a simple manner.

[0003] In the context of the planning of production plants using such a Cartesian motion system, digital three-dimensional models are often constructed in order to simplify the planning of the production plant. The construction of these models is very time-consuming by hand. SUMMARY

[0004] An advantage of the invention is that a digital overall model is automatically constructed when a Cartesian motion system is installed. Furthermore, individual linear motion systems of the product set can be assembled into a Cartesian motion system particularly simply and quickly. A real motion system and its digital overall model can thus be constructed quickly and simply.

[0005] According to claim 1, a method for generating a digital overall model of a Cartesian motion system is proposed, which method comprises the following steps:

[0006] a) providing a product set of linear motion systems which can be assembled into a Cartesian motion system, wherein each linear motion system comprises a housing, a slider, a drive and a rotary position sensor and a digital nameplate, wherein the slider is linearly movably supported at the housing in the direction of a longitudinal axis, wherein the slider can be driven in the direction of the longitudinal axis by means of the drive, wherein the housing and / or the slider respectively have standardized fastening means which are configured in such a way that fastening means selected, preferably arbitrarily selected, from two linear motion systems of the product set can be firmly connected to one another in at least one fixedly predetermined relative arrangement, wherein the rotary position of the longitudinal axis relative to the direction of the gravitational force and / or the geomagnetic field can be measured by means of the rotary position sensor, wherein digital information is stored in the digital nameplate from which the construction type of the associated linear motion system can be derived, wherein these digital information can be read wirelessly or by wire;

[0007] b) providing a digital individual model of each linear motion system of the product set, wherein the digital individual model comprises a description of the three-dimensional geometry of the linear motion system, preferably including the movability with respect to the associated longitudinal axis;

[0008] c) assembling a Cartesian motion system using any selected linear motion systems of the product set;

[0009] d) reading the digital nameplate of each linear motion system of the assembled Cartesian motion system and calling the associated digital individual model using the data read from the associated digital nameplate;

[0010] e) measuring the rotational position of each linear motion system of the assembled Cartesian motion system using the associated rotational position sensor and generating a digital overall model of the entire assembled Cartesian motion system using the measured rotational positions and the called digital individual models of the linear motion systems.

[0011] The steps are preferably carried out in the order stated. The housings of the linear motion systems preferably each extend in the direction of the associated longitudinal axis. The linear motion systems preferably each comprise at least one linear rolling bearing with a guide rail and a guide carriage, wherein the guide rail extends parallel to the longitudinal axis, wherein the linear rolling bearing has at most preferably continuously encircling spherical rolling bodies. The drives of the linear motion systems preferably each comprise a belt drive, in particular a toothed belt transmission, and / or a screw drive, in particular a ball screw drive. The drives of the linear motion systems preferably comprise electric motors. All electric motors of the product set preferably have uniform electrical plug connections via which electrical energy and electrical control and measurement information can be exchanged with a control device. The digital nameplates are preferably read automatically. The entire method is preferably carried out automatically, with the exception of the assembly of the Cartesian motion system. The digital individual models and / or the overall model can be stored, for example, using the so-called STEP standard (http: / / en.wikipedia.org / wiki / ISO_10303), wherein any other data format for storing geometric 3D models can be used.

[0012] Advantageous refinements and improvements of the application are specified in the dependent claims.

[0013] It can be provided that the digital individual models are stored in a database and can be called from there. In this way, particularly detailed individual models can be provided with a short access time. Furthermore, a large number of individual models can also be maintained without any problems.

[0014] It can be provided that for each individual model of a number in the database an explicit instance code is assigned and stored in the database, wherein the instance code is stored in the nameplate of the number of the associated linear motion system, so that the individual model of the number can be called from the database using the instance code. Only little storage space is therefore required in the nameplate of the number, so that the nameplate of the number can for example be designed as an RFID tag. The explicit instance code can for example relate to a natural number.

[0015] It can be provided that the individual models of the numbers are stored in and can be called from the respective associated nameplate of the number. Confusion can thereby be avoided when assigning individual models and linear motion systems. Furthermore, the operation of a server for providing the database can be dispensed with.

[0016] It can be provided that the standardized fixing means are designed in such a way that fixing means selected, preferably arbitrarily selected, from the two linear motion systems of the product set can only be firmly connected to one another in a unique, fixed relative arrangement. In this unique relative arrangement, the two associated longitudinal axes are preferably arranged perpendicular to one another. Only the axial orientation of the Cartesian coordinate system therefore has to be determined using a rotary position sensor. A particularly simple rotary position sensor can be used. When creating the overall model, only one of the possible relative arrangements in the two linear motion systems has to be taken into account.

[0017] It can be provided that the standardized fixing means comprise at least one clamping means which can be clamped and released again manually without a tool. The Cartesian motion system can thereby be assembled particularly quickly.

[0018] It can be provided that the standardized fixing means comprise a form-fitting calibration means which can be form-fittingly engaged when the clamping means are released, wherein the relative position of the two fixing means in the engaged state is determined form-fittingly when the clamping means are clamped. The relative position is preferably only determined form-fittingly when the clamping means are clamped. Correspondingly, a frictional fit should not be given at all, in particular a frictional fit which enables an infinitely adjustable relative position should not be given. The relative position should rather be firmly predetermined by the calibration means and the clamping means. When creating the overall model, only one of the possible relative positions in the two linear motion systems therefore has to be taken into account.

[0019] It can be provided that the fixing means comprise an electrical plug connector. The contact engagement at the electrical plug connector and the calibration engagement between the fixing means can preferably be established simultaneously in one method step. The electrical plug connector and the form-fitting calibration means preferably have the same movement direction for releasing or establishing the respective engagement.

[0020] It can be provided that a movement trajectory of the Cartesian movement system is predetermined, wherein the timing of the movement is optimized automatically in the case of use of the overall model in digital form in such a way that the movement time is as short as possible, wherein at the same time the Cartesian movement system is not overloaded and / or is not below the predetermined service life of the Cartesian movement system. With the overall model established according to the application, substantially all the data required for the optimization are present. The user only has to predetermine the movement trajectory in order to carry out the optimization.

[0021] It can be provided that the movement of the Cartesian movement system is detected, wherein the remaining service life of the Cartesian movement system is calculated in the case of use of the overall model in digital form. The calculation of the remaining service life can be carried out automatically in the case of use of the overall model according to the application, without the user having to input further data for this purpose. The movement of the Cartesian movement system is preferably detected in such a way that the drive control signals of the drives are detected, wherein the movement of the Cartesian movement system can be calculated from these drive control signals.

[0022] It can be provided that the movement of the Cartesian movement system is detected, wherein the lubrication time point is determined in such a way that a state of lack of lubrication is substantially excluded in the case of use of the overall model in digital form. The lubrication time point can be determined automatically in the case of use of the overall model according to the application, without the user having to input further data for this purpose. The lubrication time point should mean the time point at which lubricant is supplied to the Cartesian movement system. This supply of lubricant can take place manually, for example by feeding lubricating grease to the lubricating connections of the movement system. The supply of lubricant can also take place automatically.

[0023] Of course, the features described previously and explained in the following can be used not only in the combinations indicated, but also in other combinations or alone, without leaving the scope of the application. BRIEF DESCRIPTION OF DRAWINGS

[0024] The application is explained in more detail below with the aid of the drawings. In the drawings:

[0025] Figure 1 is a perspective view of a Cartesian movement system with a linear movement system;

[0026] Figure 2 is a perspective, partial view of a first linear movement system, in which the corresponding fixing means of the first type can be seen;

[0027] Figure 3 is a perspective view of a second linear movement system, in which the two corresponding fixing means can be seen;

[0028] Figure 4 is a perspective view of a third linear movement system, in which the corresponding fixing means of the second type can be seen. DETAILED DESCRIPTION

[0029] Figure 1 A perspective view of a Cartesian motion system 10 with three linear motion systems 20; 20a; 20b; 20c is shown. Corresponding linear motion systems without an energy guide chain 60 and the associated chain housing 61 that can be used within the scope of the present application are known from DE 197 38 988 B4, EP 340 751 B2, DE 200 80 368 U1, EP 828 083 B1, EP 1 975 463 B1, DE 103 54 040 A1, DE 10 2008 026 770 A1, EP 2 218 926 B1 or US 2005 / 265639. The linear guide mechanisms of these linear motion systems typically comprise linear rolling bearings, which mostly have continuously encircling, spherical rolling bodies. The drives can be designed electrically, pneumatically, linearly driven, piezomechanically or in any other conceivable way.

[0030] All linear motion systems 20 of the product family (from which a Cartesian motion system 10 is assembled) have in common that they each have a housing (number 22 in Figures 2 to 4 ) which extends along the associated longitudinal axis 21. An associated slide (number 23 in Figures 2 to 4 ) is supported in or at the housing (number 22 in Figures 2 to 4 ) in such a way that it can be moved in the direction of the associated longitudinal axis 21. In addition, an associated drive 24 is provided with which the slide can be driven in the direction of the longitudinal axis 21. The product family with these features is known from the catalog accessible under the address http: www.boschrexroth.com / various / utilities / mediadirectory / download / index.jsp object_nr=R999000044 on October 30, 2019.

[0031] The current linear motion system 20; 20a; 20b; 20c is furthermore equipped with a rotational position sensor 25, which is preferably fixed at the associated housing 22. With the rotational position sensor 25 the rotational position of the associated longitudinal axis 21 relative to the direction of the gravitational force and / or relative to the earth's magnetic field can be measured. Corresponding sensors are known, for example, from the web page http:www.bosch-sensortec.com / bst / products / all_products / bno055. The sensors preferably comprise a micro-mechanical system (MEMS), which is manufactured from a semiconductor substrate by means of a photochemical etching process. Furthermore, an electronic nameplate 26 is provided for each linear motion system 20; 20a; 20b; 20c. The electronic nameplate 26 relates to a digital information store, in which digital information is stored, from which the type of construction of the associated linear motion system 20; 20a; 20b; 20c can be derived, wherein these digital information can be read automatically wirelessly or wired. Such an information store can be combined with the rotational position sensor 25 in one component. It is also conceivable, however, that the digital nameplate 26 is integrated into the associated electric motor 27, so that the digital nameplate can be read via the connection cable thereof. In the digital nameplate 26 an instance code can be stored, wherein for each possible type of construction of the linear motion system 20; 20a; 20b; 20c a specific instance code is provided. The instance code relates in the simplest case to a natural number.

[0032] Furthermore, the linear motion system 20; 20a; 20b; 20c is equipped with at least one standardized fixing means, which is referenced Figures 2 to 4 is explained in more detail. In the case of the use of fixing means, the linear motion systems 20; 20a; 20b; 20c are assembled into a Cartesian motion system 10 in such a way that the associated longitudinal axes 21 are each arranged perpendicularly to one another in pairs, so that the three longitudinal axes 21 span a Cartesian coordinate system. By means of the three drives 24 the gripper 72 is currently made freely movable in this coordinate system. Instead of the gripper 72 any other tool can be provided, which is preferably automatically maneuverable. The current fixing means are designed in such a way that they each allow only one unique relative position of two linear motion systems 20; 20a; 20b; 20c mounted next to one another. It is also possible in the present embodiment that the third linear motion system 20c is built directly onto the first linear motion system 20a.

[0033] Figure 2 A perspective partial view of the first linear motion system 20a is shown, in which a first embodiment of a fixing means 33 can be seen, which is designed according to the first type 31. The fixing means of the first type 31 are provided for the mounting of a fixing means of the second type 32, which is designed according to the second type 32. The fixing means of the second type 32 are provided for the mounting of a fixing means of the third type 34, which is designed according to the third type 34. The fixing means of the third type 34 are provided for the mounting of a fixing means of the fourth type 35, which is designed according to the fourth type 35. Figure 3 and4 32 in the figure). The first type of fixing device 31 is a more complex fixing device in this case. It comprises a calibration plate 80 having a flat surface 82 that faces the associated fixing device of the second type, wherein the calibration plate 80 is currently firmly connected to the slide 23. However, it is also conceivable that the calibration plate 80 of the first type of fixing device 31 is connected to the housing 22, thereby creating corresponding combination possibilities within the product portfolio of linear motion systems. Of course, the flat surface 82 can also be integrally provided on the slide 23 or the housing 22, in which case the calibration plate 80 is omitted.

[0034] The flat surface 82 is aligned parallel to the longitudinal axis 21 of the linear motion system 20a with the associated fixing means 31 of the first type and parallel to the longitudinal axis 21 of the other linear motion system ( Figure 3 The longitudinal axis of the number 20b) is aligned with the second type of fixing device ( Figure 3 32 in the figure. Flat surface 82 is currently equipped with calibration means 41 in the form of two calibration screws 42 oriented perpendicularly to flat surface 82. Calibration screws 42 are currently designed as separate components that are screwed to calibration plate 80. They can be equipped with a ball head to facilitate installation. These calibration screws 42 are also referred to as "receiving screws with a ball attachment." DIN 6321B and DIN 6321C describe other usable calibration screws.

[0035] Furthermore, the calibration plate is provided with a support pin 44, which serves to support the weight of the further linear motion system during installation. Reference is made to the German patent application with the document number 102019209806 for this purpose. The only possible relative position of the two involved linear motion systems is determined by the form fit of the flat surface 82 and the calibration bolt 42. This position is currently ensured by a clamping device 40 in the form of two clamping rods 83. The currently selected embodiment of the clamping rod 83 is also referred to as a "pivoting clamp with an eccentric rod". The clamp 86, which can be clamped relative to the second type of fixing device with an eccentric rod, can be pivoted about an axis oriented perpendicular to the flat surface 82. This simplifies the assembly of the further linear motion system. Figure 2 In FIG, two end positions of the clamping rod 83 and the clamp 86 are shown simultaneously.

[0036] Furthermore, the calibration plate 80 is provided with a plug connector 84. This plug connector is designed to be purely electrical in the present case, wherein a pneumatic plug connector can be provided in addition or alternatively. The plug connector 84 is provided in the present case for plugging into a loosened mating plug connector ( Figure 385 in the figure) and is therefore arranged close to the calibration screw 42. However, it is also conceivable that the associated mating connector is fixedly integrated into an associated fixing means of a second type. The calibration screw 42 and the plug connector 84 can then preferably be arranged at a small distance from each other, so that a corresponding engagement can be easily established.

[0037] The rotational position sensor 25 and the numbered nameplate 26 are integrated in the present case into a common housing sub-housing, which is fixedly arranged at the location indicated by the dashed line on the housing 22. The housing sub-housing is located in particular in the end region of the first linear motion system 20a.

[0038] In the present case, the drive of the first linear motion system 20 a comprises a toothed belt which is in drive connection with an electric motor 27 .

[0039] Figure 3 A perspective view of the second linear motion system 20b is shown, wherein two corresponding fixing means 30; 31; 32; 34; 35 can be seen. A first type of fixing means 31 is arranged on the slide 23, which is designed essentially in the same way as the fixing means arranged on the first linear motion system. This can be seen in the example of FIG. Figure 2 The explanation, in which Figure 2 and 3 In the embodiment, the same or corresponding parts are marked with the same reference numerals. Figure 2 The difference between the first embodiment (number 33 in the figure) and the second embodiment 34 occurs only in the immediate vicinity of the engagement between the first and second types of fastening means. In particular, the first type of fastening means 31 can be designed as freely as possible, as long as the standardized engagement between the first and second types of fastening means is not impaired. In the second embodiment of the fastening means 34, the support pin ( Figure 2 44 in the figure), wherein these supporting pins can also be provided. The relative position between the supporting pins and the fastening screws is preferably designed to be identical in all embodiments with respect to the distance dimension 87. This distance 87 is measured from the side of the docking calibration plate 81 that abuts the calibration pins during installation.

[0040] Furthermore, at the second linear motion system 20b there is provided a second type of fixing means 32, which forms a third embodiment of the fixing means 35. The fixing means 35 comprises a flat surface 82, which abuts against the flat surface at the first type of fixing means. The flat surface 82 is currently arranged at a separate docking calibration plate 81, which is currently fixed at the housing 22 of the second linear motion system 20b. The housing 22 currently comprises a separate chain housing 61, in which an energy guide chain is arranged. The docking calibration plate 81 is currently fixed at this chain housing. It can of course also be fixed at another part of the housing 22 or be constructed in one piece with the housing 22. The flat surface 82 is typically arranged in an end region of the housing 22, so that the movement path of the slide is optimally utilized. The docking calibration plate 81 is currently designed in the form of a flat plate of constant thickness, which has a rectangular contour. It is only important in this respect that on the side facing away from the flat surface 82 there is a docking clamping face for the clamping device 40, the number 86 in Figure 2

[0041] Furthermore, the docking calibration plate 81 is equipped with two calibration means 41 in the form of calibration bores 43, which match the calibration screws (number 42 in Figure 2

[0042] It is also pointed out that a docking plug connector 85 is inserted into the plug connector (number 84 in Figure 2

[0043] The rotary position sensor 25 and the digital nameplate 26 are currently integrated into a common sub-housing, which is firmly arranged at the housing 22 at the point marked with a dashed line. The sub-housing is in particular in an end region of the second linear motion system 20b.

[0044] ​​​The drive of the second linear motion system 20b currently comprises a ball screw drive, which is in driving connection with the electric motor 27 via a toothed belt.

[0045] Figure 4 A perspective view of the third linear motion system 20c is shown, in which the corresponding fixing means 32 of the second type can be seen. A corresponding docking alignment plate 81 with a flat surface 82 is fixed at the slide 23. This docking alignment plate is in turn designed as a rectangular flat plate of constant thickness. The spacing of the alignment bores 43 in the fourth embodiment of the fixing means 36 coincides with the fixing means 35 in the third embodiment (cf. Fig. 3), so that interchangeability of the two variants is obtained. The contour of the docking alignment plate 81 is designed differently in the two described embodiments, since the contour is of subordinate importance in the context of standardization, apart from the spacing dimension 87. Figure 3

[0046] At present, a clamp 72 is fixed at the housing 22 of the third linear motion system 20c. It is also conceivable that the housing 22 is equipped with the fixing means of the first type in order to enable the retrofitting of another linear motion system. In the context of the product family according to the application, it is preferred to provide at least two linear motion systems, which differ only in the equipped fixing means.

[0047] The rotary position sensor 25 and the digital nameplate 26 are currently integrated into a common sub-housing, which is firmly arranged at the housing 22 at the location marked with a dashed line. The sub-housing is in particular in the end region of the third linear motion system 20c.

[0048] The drive of the third linear motion system 20c currently comprises a ball screw drive, which is in direct driving connection with the electric motor 27.

[0049] List of reference signs

[0050] 10 Cartesian motion system

[0051] 20 linear motion system

[0052] 20a first linear motion system

[0053] 20b second linear motion system

[0054] 20c third linear motion system

[0055] 21 longitudinal axis

[0056] 22 housing

[0057] 23 slide

[0058] 24 drive​

[0059] 25 rotational position sensor

[0060] 26 digital nameplate

[0061] 27 electric motor

[0062] 30 securing means

[0063] 31 securing means of the first type

[0064] 32 securing means of the second type

[0065] 33 securing means of the first embodiment

[0066] 34 securing means of the second embodiment

[0067] 35 securing means of the third embodiment

[0068] 36 securing means of the fourth embodiment

[0069] 40 clamping means

[0070] 41 calibration means

[0071] 42 calibration bolt

[0072] 43 calibration bore

[0073] 44 support pin

[0074] 45 plug connector at the securing means

[0075] 60 energy guide chain

[0076] 61 chain housing

[0077] 70 base plate

[0078] 71 stand

[0079] 72 clamp

[0080] 80 calibration plate

[0081] 81 docking calibration plate

[0082] 82 flat surface

[0083] 83 clamping lever

[0084] 84 plug connector

[0085] 85 docking plug connector

[0086] 86 clamp

[0087] 87 spacing of the calibration bore to the side for the support pin

Claims

1. A method for generating a digital general model of a Cartesian motion system (10), comprising the following steps: a) providing a product set consisting of linear motion systems (20; 20a; 20b; 20c) that can be assembled into a Cartesian motion system (10), wherein: Each linear motion system (20; 20a; 20b; 20c) comprises a housing (22), a slide (23), a drive (24) and a rotational position sensor (25) as well as a numbered nameplate (26), wherein the slide (23) is supported on the housing (22) so as to be linearly movable in the direction of the longitudinal axis (21), wherein the slide can be driven in the direction of the longitudinal axis (21) by the drive (24), wherein the housing (22) and / or the slide (23) each have a standardized fixing device (30-36), which is constructed in such a way that two types of fixing devices from the product set can be used. Selected fastening elements (30-36) of a linear motion system (20; 20a; 20b; 20c) can be firmly connected to one another in at least one fixedly predetermined relative arrangement, wherein the rotational position of the longitudinal axis (21) relative to the direction of gravity and / or relative to the Earth's magnetic field can be measured by a rotational position sensor (25), wherein digital information is stored in a digital nameplate (26), from which the design type of the relevant linear motion system (20; 20a; 20b; 20c) can be inferred, wherein the digital information can be read wirelessly or by wire; b) providing a digital individual model of each linear motion system (20; 20a; 20b; 20c) of the product set, wherein the digital individual model comprises a description of the three-dimensional geometry of the linear motion system (20; 20a; 20b; 20c), including the movability with respect to the associated longitudinal axis (21); c) assembling a Cartesian kinematic system (10) using any selected linear kinematic system (20; 20a; 20b; 20c) from the product set; d) reading the numerical nameplates (26) of the individual linear kinematic systems (20; 20a; 20b; 20c) of the assembled Cartesian kinematic system (10) and calling up the associated numerical individual model using the data read from the relevant numerical nameplates (26); e) measuring the rotational positions of the individual linear motion systems (20; 20a; 20b; 20c) of the assembled Cartesian motion system (10) using the associated rotational position sensors (25) and generating a digital overall model of the assembled entire Cartesian motion system (10) using the measured rotational positions and the called digital individual models of the individual linear motion systems (20; 20a; 20b; 20c).

2. The method according to claim 1, wherein The individual models of the numbers are stored in a database and can be called up from there.

3. The method according to claim 2, wherein: Each digital individual model in a database is assigned a unique instance code and stored in the database, wherein the instance code is stored in a digital nameplate (26) of the associated linear motion system (20; 20a; 20b; 20c), so that the digital individual model can be called up from the database using the instance code.

4. The method according to claim 1, wherein The individual models of the numbers are stored in the respective assigned number plate (26) and can be called up from there.

5. A method according to any one of the preceding claims, wherein The standardized fixing means (30-36) are designed in such a way that fixing means (30-36) selected from two linear motion systems (20; 20a; 20b; 20c) of the product set can only be firmly connected to each other in a single fixed predetermined relative arrangement.

6. The method according to any one of claims 1 to 4, wherein The standardized fastening means (30-36) include at least one clamping means (40) which can be tightened and loosened again manually without tools.

7. The method according to claim 6, wherein The standardized fixing means (30-36) comprises a form-fitting calibration means (41) which can be engaged in a form-fitting manner when the clamping means (40) is loosened, wherein when the clamping means (40) is clamped, the relative position of the two engaged fixing means (30-36) is determined in a form-fitting manner.

8. The method according to any one of claims 1 to 4, wherein The fixing means (30-36) include an electrical plug connector (84).

9. The method according to any one of claims 1 to 4, wherein The movement trajectory of the Cartesian motion system (10) is predetermined, wherein the timing of the movement is automatically optimized using the digital overall model in such a way that the movement time is as short as possible, while at the same time the Cartesian motion system (10) is not overloaded and / or does not fall below a predetermined service life of the Cartesian motion system (10).

10. The method according to any one of the preceding claims 1 to 4, wherein The movement of the Cartesian kinematic system (10) is detected, wherein the remaining service life of the Cartesian kinematic system (10) is calculated using the digital overall model.

11. The method according to any one of the preceding claims 1 to 4, wherein The movement of the Cartesian kinematic system (10) is detected, wherein the lubrication time is determined using the digital overall model in such a way that a state of lack of lubrication is excluded.

12. The method according to claim 1, wherein The fixing means are selected arbitrarily.

13. The method according to claim 5, wherein: The fixing means are selected arbitrarily.

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