Patent Application
20170038745
The invention relates to a method for operating an automation arrangement according to the preamble of claim 1.
The prior art discloses programmable logic controllers (PLCs) that can be used in automation engineering to program and automatically actuate actuators, particularly end effectors and provision systems, and also sensors and other functional units of a machine or installation. A functional element of this kind, which is actuatable by a programmable logic controller, in principle, is generally referred to both individually and in a combination, here and subsequently, as an input/output module. Conventionally, these programmable logic controllers have been provided by devices and electronic arrangements provided specifically for this purpose. Habitually, such programmable logic controllers communicate with the input/output module that they are configured to actuate via a bus, such as e.g. a field bus.
In the meantime, programmable logic controllers whose functionality is provided by a computer program executed on a computer are also known. Such a computer program can be referred to as a PLC computer program, the system operated using such a PLC computer program being able in turn to be referred to as a soft PLC as a whole. There is thus no further provision for special hardware for the programmable logic controller, but rather its functionality is formed by a computer program that runs on a conventional computer or on an industrial PC or embedded PC tailored to the automation environment. For the purpose of actuating the input/output modules, such a computer may accordingly likewise be connected to a field bus.
The prior art and specifically EP 1 586 967 A2, on which the present invention is based, also disclose expansions through software for such a PLC computer program. One such known expansion can e.g. be used to allow communication with a specific device by a driver or the like. However, the expansions presented in this prior art are expansion modules such as e.g. dynamic program libraries or DLLs (dynamic-link libraries) that can be addressed or incorporated by the PLC computer program. They are thus ultimately under the software control of the PLC computer program in this case. There is no provision for control of the programmable logic controller for software purposes by this expansion.
When automation cells are part of an automation system, it is habitually the case that an input/output module actuated by a programmable logic controller is arranged on a manipulator, which is e.g. a multi-axis robot. Specifically, the input/output module may be arranged at the tool center point (TCP) of the manipulator.
Such a manipulator habitually has its movements actuated by a numerical controller, here and subsequently referred to as an NC controller. This NC controller can also, in principle, be provided by a computer program executed on a computer. The provision of the input/output module on the manipulator closely relates the activities performed by the input/output module—which are prescribed e.g. by the PLC computer program—and the movements of the manipulator—which are in turn controlled by the NC controller.
Against this background, the object of the invention is to improve a method for operating an automation arrangement, and particularly an automation arrangement in which the functionality of a programmable logic controller is provided by a computer program, such that improved integration between the computer program for the programmable logic controller and an NC controller for the actuation of a manipulator is made possible.
The cited problem is solved for a method for operating an automation arrangement having the features of the preamble of claim 1 by the features of the characterizing part of claim 1.
An essential aspect of the invention is the insight that, besides a PLC computer program for providing a programmable logic controller, and in a manner superordinate to said programmable logic controller in terms of software, there is a cell control computer program provided on the computer apparatus, which cell control computer program firstly actuates the input/output module by actuating the interface of the PLC computer program and secondly provides the function of an NC controller, this cell control computer program itself then performing the actuation of the manipulator and of other components.
In other words, this cell control computer program forms the superordinate—for software purposes—“roof” that has all the necessary functions for the automation arrangement, including the PLC functionality, under its control and in this way can coordinate them with one another. In this case, the functionality of the PLC computer program can be accessed in modular fashion, this PLC computer program being able to be introduced into the overall system as a component that is already present. This standardization under the roof of the cell control computer program can also outwardly provide a standard interface of the system as a whole but in turn allows actuation of the automation arrangement in a standard manner.
The preferred embodiment according to subclaim 3 relates to advantageous bus systems for linking the input/output modules and the manipulators to the computer apparatus.
The preferred embodiments of subclaims 6 to 8 in turn describe meaningful splits for the PLC computer program or the cell control computer program within an operating system and a process structure of the computer apparatus.
Subclaim 9 describes advantageous possibilities for interprocess communication on the computer apparatus between the cell control computer program and the PLC computer program that meet particularly the synchronization demands on these two programs.
Subclaims 10 to 12 describe the embodiment of an NC processor as part of the cell control computer program and its specific interaction with the PLC computer program, on the one hand, and the actuation of the manipulator, on the other.
As described by subclaims 13 to 15, an object-oriented software architecture is used to great advantage for this actuation of the manipulator and other access operations.
Further details, features, aims and advantages of the present invention are explained below with reference to the drawing of a preferred exemplary embodiment. In the drawing,
The method according to the proposal is used for operating an automation arrangement 1 having a manipulator 2a, b and an input/output module 3a, b, the manipulator 2a, b and the input/output module 3a, b each being configured for automated production.
Such an automation arrangement 1 is shown in
The automation arrangement 1 that is intended to be operated using the method according to the proposal further has a computer apparatus 5. The automation arrangement 1 may particularly be an automation cell 1a, that is to say a modular arrangement for automation within a larger automation system e.g. of a larger factory.
According to the proposal, the computer apparatus 5 is used to execute a PLC computer program 6 for providing a programmable logic controller for the input/output module 3a, b, the PLC computer program 6 being communicatively connected to the input/output module 3a, b via a module bus 7 for the purpose of actuating said input/output module.
The method according to the proposal is now characterized in that the computer apparatus 5 is used to execute a cell control computer program 8 for actuating the PLC computer program 6 via a PLC interface 9 of the PLC computer program 6, in that the cell control computer program 9 provides an NC controller 10 for the manipulator 2a, b and in that the cell control computer program 8 is communicatively connected to the manipulator 2a, b via a network bus 11 for the purpose of actuating said manipulator.
As in the present case, the manipulator 2a, b may be a multi-axis manipulator, and particularly a six-axis manipulator. The computer apparatus 5 may also consist of multiple individual computer units. Similarly, both the PLC computer program 6 and the cell control computer program 8 may be constructed from a series of individual computer programs that can each also be executed in a separate process. Details in this regard are described below.
In a preferred embodiment, the input/output module 3a, b has an application apparatus 12 arranged on the manipulator 2a, b. The input/output module 3a, b may also consist of such an application apparatus 12. This application apparatus 12 may be arranged particularly at the tool center point of the manipulator 2a, b, and it may preferably be a tool, a measuring apparatus or a receptacle in this case. The application apparatus 12 can then be actuated particularly by the PLC computer program 6 by virtue of actuation of the input/output module 3a, b itself
Further, it is preferred for the module bus 7 to be a field bus 13. Alternatively or additionally, the network bus 11 may be an Ethernet bus 14, with particularly a realtime Ethernet bus 14a being possible in this case. A realtime Ethernet bus 14a is an Ethernet bus based on a protocol that provides a realtime capability.
Similarly, it is preferred for the cell control computer program 8 to be communicatively connected to a sensor apparatus 15a, b via the network bus 11 for the purpose of reading the sensor apparatus 15a, b. In the exemplary embodiment of
The automation arrangement 1 and specifically the automation cell 1a can—as already stated—be part of a larger automation system, which is controlled e.g. centrally, together with other automation arrangements. In such a case, there is preferably provision for the cell control computer program 8 to provide a cell control interface via a factory bus 16, for which factory bus 16 the cell control computer program 8 is communicatively connected. An appropriate factory bus driver 16a is shown in
In principle, the computer apparatus 5 may be any computer-type apparatus, for example specifically an industrial computer or another microprocessor system. However, it is preferred for the computer apparatus 5 to be a personal computer 17. This provides the opportunity for not only the cell control computer program 8 but also other computer programs to be executed flexibly on the computer apparatus 5. A further preference in this case is for the PLC computer program 6 and the cell control computer program 8 to run on a multimedia operating system 18 for a personal computer 17.
This relationship is shown schematically in
The cell control computer program 8 addresses the PLC computer program 6 via this PLC interface 9. At the same time, the cell control computer program 8 has a network bus driver 8a for the communicative connection to the network bus 11. Other, in particular software-oriented, modules of the cell control computer program 8 are a visualization module 8b, a diagnosis module 8c, a robot module 8d, a normality sensor module 8e, a position sensor module 8f, a laser sensor module 8g and an NC module 8h. These modules communicate among one another. Further, there may be still further modules provided.
Outside the cell control computer program 8, and on the operating system, which in this case is the multimedia operating system 18, there now in turn runs—besides the above factory bus driver 16a for the communicative connection to the factory bus 16—a configuration module 18a, which allows e.g. access to the cell control computer program 8 via a conventional user interface of the multimedia operating system 18 for configuration purposes.
A further preference is for the PLC computer program 6 and the cell control computer program 8 each to be executed by different processes. In the present case, the term process is intended to be understood for software purposes. Both the PLC computer program 6 and the cell control computer program 8 can each be executed by a single process in this case. However, it may also be that the PLC computer program 6 and the cell control computer program 8 are each executed by a multiplicity of different processes. The split for the PLC computer program 6 or the cell control computer program 8 over the single processes can correspond to the split into the modules shown in the representation of
A preferred split for the cell control computer program 8 into different processes provides for an NC computer subroutine of the cell control computer program 8 for providing the NC controller 10 to be executed in an NC process and for a manipulator subroutine of the cell control computer program 8 for actuating the manipulator 2a, b to be executed in a manipulator process. In this case, the manipulator process is thus different than the NC process. The NC controller 10—and hence the NC computer subroutine—processes NC commands that relate firstly to an actuation of the input/output module 3a, b and secondly to an actuation of the manipulator 2a, b. The information obtained from the NC commands in relation to the actuation of the manipulator 2a, b, that is to say “purged” of the information in relation to the actuation of the input/output module 3a, b, can then be processed by the manipulator subroutine. This NC subroutine for providing the NC controller 10 may—as shown in the representation in
The PLC interface 9 of the PLC computer program 6 can, in principle, be addressed by any programs and accordingly from different processes. Firstly, it is addressed by the cell control computer program 8 for the purpose of actuating the input/output module 3a, b, and secondly, the PLC interface 9 is also used to provide data for retrieval that can then be presented on a screen of the computer apparatus 5, for example by the visualization module 8b of the cell control computer program 8.
It may also be that system processes of an operating system of the computer apparatus 5 and particularly of the multimedia operating system 18 need to access the PLC interface 9 of the PLC computer program 6. To produce synchronization between the actions of the input/output module 3a, b and the movements of the manipulator 2a, b, access for actuating the input/output modules 3a, b is habitually more important and particularly more time critical than visualization on a screen, for example.
Therefore, it is preferred for the computer apparatus 5 to provide multiple interprocess channels for communication with the PLC computer program 6, specifically with different prioritization at least in part. In the present instance, prioritization means the order in which a relevant communication via such an interprocess channel is processed by the operating system, a communication via an interprocess channel with a higher priority being reacted to more quickly than a communication via an interprocess channel with a lower priority. Specifically, a process having a higher priority can interrupt a process having a lower priority that is currently being processed.
This can be accomplished firstly by virtue of a single process providing the communication via the interprocess channels and handling said communication on the basis of the respective priority of the interprocess channels. Alternatively or additionally, each interprocess channel may be allocated to a process with a priority corresponding to the priority of the interprocess channel, with the respective process then being handled on the basis of its priority.
Further, it is preferred for the NC computer subroutine and a visualization program executed in a visualization process each to communicate with the PLC computer program 6 via an interprocess channel and for the interprocess channel of the NC computer subroutine to have a higher priority than that of the visualization program. This takes account of the described circumstance that the actuation by the NC computer subroutine is more important and needs to be executed more quickly than a visualization.
Referring to the representation of
The NC processor 19 can firstly consist of multiple modules that are each executed in a separate process. Alternatively, the NC processor 19 as a whole can be executed in one process, this particularly being able to be the NC process above. Hence, the NC processor 19 may particularly correspond to or be comprised by the NC computer subroutine above. Consequently, the NC processor may also be formed by the NC module 8h above.
The NC program 20 above is, then, a succession of NC commands that are composed in a plain text. This is also referred to as G code. G code can comprise G commands or else M commands and general parameters. The NC processor 19 comprises an NC interpreter 19a and an NC command converter 19b, which has access to a command database 23. The NC interpreter 19a and the NC command converter 19b translate the plain text of the NC program 20 into geometry data 22a and/or technology data 22b, on the one hand, in each case for the purpose of actuating the manipulator 2a, b, and switching commands 21 for actuating the input/output module 3a, b, on the other. In this case, production of the switching commands 21 can also be based on the technology data 22b.
The NC program 20 may also comprise references to or dependencies on sensor data, which means that there is preferably provision for the NC processor 19 also to be configured to translate the NC program 20 into sensor queries for reading the sensor apparatus 15a, b.
In the present example, the NC processor 19 also comprises an NC data collector 19c that stores automatically generated data records in a protocol database 24 during execution of the NC program.
Further, there is provision for the NC processor 19 to execute a computation routine 25 for trajectory planning for the manipulator 2a, b on the basis of the geometry data 22a and/or on the basis of the technology data 22b. Preferably, the trajectory planning performed by the computation routine 25 comprises a kinematic transformation, that is to say a conversion from Cartesian coordinates to axial coordinates or vice versa. Alternatively or additionally, the trajectory planning performed by the computation routine 25 can also comprise an interpolation. Based on the results of the computation routine 25, it is then possible for one or more position controllers 25a of the manipulator 2a to be supplied with reference variables. This variant corresponds to the representation of
According to a further variant, this computation routine 25 performs the above kinematic transformation, but not the trajectory planning. In the present case, on the basis of the kinematic transformation, a robot controller—not shown—of the manipulator 2a, b is supplied with the results of the kinematic transformation. Both the trajectory planning and the functionality of the above position controllers 25a are then accordingly provided by this robot controller.
For the input/output module 3a, b, there is specific provision for the NC processor 19 to execute the switching commands 21 by virtue of the cell control computer program 8—of which the NC processor 19 is part, of course—accessing the PLC interface 9 of the PLC computer program 6, and the PLC computer program 6 responding to the access by actuating the input/output module 3a, b via the module bus 7.
For this access and other access operations, there may be a specific type of encapsulation provided in this case, as shown hereinbelow again with reference to
Both this access to the encapsulation interface 26 and the access to the PLC interface 9 can be effected by means of an object-oriented interface class. Therefore, it is preferred for the access to the encapsulation interface 26 and/or to the PLC interface 9 to comprise the access to an object-oriented interface class 27 having the nature of a manipulator class 27a, of an input/output module class 27b, of a trajectory planning class 27c and/or of a sensor class 27d. Hence, the same interface—for the actuation of a manipulator, of an input/output module, of a trajectory planning routine or of a sensor, respectively—is thus always provided for these access operations, and any differences are encapsulated in the implementation. It is specifically possible for the access to the PLC interface 9 to comprise the access to the input/output module class 27b.
These are now taken into consideration in that, as preferred, the manipulator class 27a, the input/output module class 27b and/or the sensor class 27d are implemented by a manipulator object 28a, an input/output module object 28b and a sensor object 28d, respectively, which are dependent on the type of the manipulator 2a, b, of the input/output module 3a, b and of the sensor apparatus 15a, b, respectively. Similarly, the trajectory planning class 27d may be implemented by a trajectory planning object 28d, which is dependent on the specific algorithms that are used to implement the trajectory planning and specifically the interpolation and the kinematic transformation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 105 381.8 | Apr 2014 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/058146 | 4/15/2015 | WO | 00 |
