Integration of Time Management in the Digital Factory

Transcription

1 Integration of Time Management in the Digital Factory Ulf Eberhardt a,, Stefan Rulhoff b,1 and Dr. Josip Stjepandic c a Project Engineer, Daimler Trucks, Mannheim, Germany b Consultant, PROSTEP AG, Darmstadt c Head of Competence Center CA Technology, PROSTEP AG, Darmstadt Abstract. This paper reflects the current work on the integration of Time Management in the Digital Factory. To eliminate deficits in the integration of leading planning tools, a methodical approach was established in order to develop application protocols based on a systematic basis for the Digital Factory. Therefore, a joint project with both industrial and research partners has been initiated. Beside the fundamental methodology for the standardisation in the Digital Factory as further important result an interface between the software products Teamcenter Manufacturing and TiCon will be developed. Keywords. digital factory, time management, application protocol, STEP, PLM services 1 Initial Situation Today globally operating companies face due to the increasing complexity of processes and products, the growing demands on flexibility and the shortened development cycles additional challenges. This leads more than ever to a conflict between time - cost - quality in design, development, acquisition and commissioning at different locations. Furthermore these plants represent independent organizational units within affiliated groups, which have grown with hierarchically self-sufficient IT and staffing. An approach to handle this situation is the introduction of production systems, such as adaptations of the Toyota Production System (TPS). This methods, designed and established in the mid of 1990 s allow the standardization of the production of enterprise-equitable and corporate assembly-groups, aggregates and finished products in worldwide locations to a large extent. As an example one engine architecture for heavy-duty engines from Daimler Trucks is planned and manufactured by Detroit Diesel (Detroit, USA), Mercedes-Benz (Mannheim, Germany) and partially by Mitsubishi Fuso (Kawasaki, Japan). The introduction of such standardized methods and processes abet the implementation of the digital factory as an additional approach 1 Consultant, PROSTEP AG, Dolivostrasse 11, Darmstadt, Germany; Tel: +49 (0) ; Fax: +49 (0) ; stefan.rulhoff@prostep.com;

2 2 U. Eberhardt, S. Rulhoff and J. Stjepandic to encounter the new challenges. Today the concept of the digital factory is used in industrial enterprises in order to plan and secure the manufacturing of products with the necessary processes in the early phases of product development, and to optimize existing processes. The digital support of these planning processes includes methods, models and tools that enable the integrated planning of production processes [1]. Thereby the traceability, validation and optimization of existing processes are secured, the planning quality will be increased and the planning cycle on the whole noticeable shortened. The implementation of the digital factory and therefore the digital production planning is not yet well advanced in many companies. But such an integrated IT environment is the base of the parallelization of development and planning processes necessary for the efficient use of concepts such as the simultaneous and concurrent engineering. This IT integration is well implemented in the product development. In the planning departments the corresponding system environment, the digital factory lacks of integration and standardization. The reasons for this are multifaceted and partly founded in the necessary requirements for the implementation of the digital factory in companies. 2 Requirements and need for action In this situation, where global operating manufactures have varying processes, methods and standards in different locations, also the existing systems of the digital factory often differs from location to location. Even same or similar IT environments can lead to different data processes and structures, due to the supported variability. Apart from these different data structures various data sets and planning states must be taken into account in parallelized planning processes also with respect to the increasing globalization. In addition, partner companies planning data are also supposed to be integrated into the own system at any time. The system landscape of the digital factory differs between two partners for example in an OEM and supplier partnership. In order to make it possible for international planning and production departments to learn from each other and participate in the planning of consistent and uniform production lines there are valid processes, methods and standards all across the group required which has to be implemented in the production planning department. The foundation for this is the usage of digital models and a network of methods, standards and tools for the consistent and integrated data management. Due to this challenges where conventional planning methods often reach their limits the implementation of the integrated digital factory as the central resource for the production planning is the approach to fulfill these requirements. For many OEMs as well as the Daimler Trucks the introduction of the integrated Digital Factory is an important strategic research and development goal in the next few years. Crucial to the development of a Digital Factory and the successful use of digital design tools is a continuous process support for the production and factory design. Because usually a variety of planning domains are involved in the production and because their results must be matched with each other and exchanged, it is necessary to have a continuous integrated planning process across the entire Product Emergence Process (PEP).

3 Integration of Time Management in the Digital Factory 3 Because of this requirement of a distributed planning process in a world wide concurrent engineering approach the associated data exchange is necessary and via standardized interfaces reasonable. With the development and implementation of such standardized interfaces the companies achieve the ability to flexible the applications of the Digital Factory in the company specific, heterogeneous system environment This standardization is lacking in many areas of the Digital Factory. Today often there are isolated applications which has to be connected with great effort. 3 Approach The joint project ADiFa ("Application Protocol for the harmonization process in the Digital Factory") is developing a system to allow the standardized exchange of planning data in the Digital Factory. In a basic system concept several planning domains such as time management, logistics or the layout planning shall be supported. After the system is developed it should be possible to evaluate a process model for unifying the used processes as well as a data model for exchanging planning data for each planning domain of the Digital Factory. The procedure is orientated at the standard series ISO (STEP). Within the project ADiFa the technical focus is on time management. The process model allows a common understanding and points to possible interfaces between systems that are used to support the planning process. Therefore exemplary interfaces are implemented of the software vendors involved in the project. For the integration with other systems implementation guidelines for the interface development will be elaborated. The application protocol is validated with the help of several practically relevant use cases from the user. In this publication, the current status of the work will be presented with the following priorities: Conceptual methodology Development of a process model to analyze the possible interfaces between the IT systems Development of a data model to exchange time data (e.g. for assembly planning). Implementation of the application protocol for data exchange Validation of the various project phases 3.1 Conceptual methodology The project consists of two parts built up on each other; the basic system concept and the application protocol. The basic system concept sets the frame in which different application protocols for different technical domains of the Digital Factory can be created (fig.1).

4 4 U. Eberhardt, S. Rulhoff and J. Stjepandic Figure 1. Conceptual structure of ADiFa Basic system concept setup The basic system concept is composed of a total of seven sub-sections (part A to part G) [2]. The first part provides a general overview of the basic system s functionality and structure. It introduces the systematic approach to the development of application protocols and explains the use of the basic system for the application protocol development. The second part describes a universal process model. This model will set the foundation for application-specific process models, which then determine the technical focus and the scope of validity of each application protocol. Part C represents the basic models, the basic system s main components. Application-specific data models of an application protocol can be defined, based on the basic data model. The data structures within the basic data models are defined in such a way that they are suitable for a variety of applications within the Digital Factory. Basic data models consist of objects and structures from the application protocol 214 of the ISO standard STEP and on this basis the OMG standard Product Lifecycle Management (PLM) Services 2.0. This enables the use of already existing and proven data structures. Part D of the basic system includes description methods, which are used in the data and process modelling of the basic system and the application protocols. The necessary implementation methods are defined in Part E. Thereby both, the necessary implementation architectures and formats, with which data models that are able to convert data models into a computer processable form, are specified. In Part F the necessary test methods and cases for a sufficient test of the application protocol are documented. The Glossary in Part G explains essential terms and definitions which are necessary for understanding the basic structure and development of application protocols.

5 Integration of Time Management in the Digital Factory 5 Structure of the application protocol Similar to the basic system, the application protocol also consists of 7 parts from A to G. Part A includes an introduction to the technical focus of the application protocol on time management and a delimitation to other planning domains. The further development and therefore the application protocol itself is geared to the approach of the development of application protocols from the ISO standard STEP [3]. This approach is shown in figure 2. Figure 2. Development of a STEP application protocol Part B initially defines a basic Application Activity Model (AAM), after the analysis of the user s planning processes. This process model serves on the one hand as a delimitation of the processes in relation to other technical domains and on the other hand as an analysis of the data transferred between the process steps. Consequently an Application Reference Model (ARM) is created in part C, which contains data objects and their structural relations. This data model is, with respect to certain areas of time management, divided into several sub-models. Part D specifies the Application Interpreted Model (AIM). AIM is a XML model representing the data format for the data exchange. In this part the mapping of the application data model into the exchange format is defined using the basic data model. Implementation guidelines for the implementation of the program interfaces are found in Part E. They will enable the implementation for the static and dynamic data exchange. For the dynamic data exchange web services are defined in the context of an SOA approach. In Part F different validation scenarios are built. Here various parts of the application protocol will be evaluated according to defined criteria and validated. Finally in part G, an application-specific glossary is created. The defined concepts in part C reflect the understanding of also partially misunderstood technical terminologies used in the application protocol. In the following a closer look is taken at the sub-sections process model, data model, implementation and validation of the application protocol. 3.2 Process model The process model or application activity model is based on the methodical representations assigned in the basic system concept. Within the application protocol specific processes are merged into the product emergence process for delimination [4]. In the classic representation the production planning joins the

6 6 U. Eberhardt, S. Rulhoff and J. Stjepandic product development and leads to the production. In addition to further analysis of scientific process models for production planning the existing planning processes of the industrial user Daimler Trucks were considered. As a result a generalized planning process was derived, which already begins during the product development and also includes planning processes for optimization during the production. Thereby sub-processes are executed in different systems. The necessary data exchange of time management data between the systems is enabled through the application protocol. The basis for this is a structured data model. 3.3 Data model The data model consists of three parts, the basic data model, the application data model and the data exchange format covering different aspects of data modeling. The basic data model provides generic basic structures through objects and their relations. In doing so, these elements were not developed lately but rather proven standards used as a basis. The ISO standard STEP provides in its application protocol AP 214 objects and structures for a process plan with hierarchical operations [5]. These objects and structures are exactly represented in the OMG PLM Services 2.0 [6] in form of UML class diagrams. The basic data model uses these objects and expands them with objects and relations which are recognized as necessary. This ADiFa extension forms, together with the standard structures, the basic data model, which represents together with the basic process model the core of the basic system. Based on that, the technical realization of the domain time management with the application process model and the application data model follow. The application data model or application reference model reflects the requirements of the users for the time management in eligible data objects. Considered are the individual time-values or -ranges and also information about the datas origin are taken into account. Therefore different sub-models are defined in the application data model. In addition to metadata, such as the user and planning date, time calculation methods and influencing factors are also included. Also important is the relation between the actual time values and the associated time codes as well as special features such as the property of value adding or non value adding. This time management system is defined in UML class models in the application data model (fig 3).

7 Integration of Time Management in the Digital Factory 7 Figure 3. ADiFa concept of process- and data models The application data model is transferred together with the basic data model into the actual data exchange format, the application interpreted model. Thereby the semantics from the application data model are mapped to the generic objects and structures of the basic data model, defining a third data model as a XML Schema. This XML schema is admitted to a PLM XML extension [7] and can then be used for exchanging data between the time management systems of the Digital Factory. 3.4 Implementation The implementation concept provides the static and the dynamic data exchange. The static data exchange occurs in form of XML files, which are compiled and read from interface processors. The dynamic data exchange transmits the data embedded in a SOA concept by using web services. In these web services the requests and the corresponding data from the application interpreted model are defined in order to be exchanged between the programs in the Digital Factory. Each program functions work both as a server to provide the data as well as a client to request data from other systems. During the ADiFa project an exemplary implementation between the systems Teamcenter Manufacturing and TICON from the vendors Siemens and MTM Softwarehaus will be developed. This system integration, with help of the ADiFa application protocol, will enable the exchange of the time management data between the involved systems. 3.5 Validation Suitable validation scenarios for the process model, data model, methodical approach and for the introduction and expansion of the Digital Factory in a SME were developed on the basis of industrial use cases. The validation of the softwaresolution, which has to be developed, is carried out by the users, based on these scenarios.

8 8 U. Eberhardt, S. Rulhoff and J. Stjepandic 4 Conclusion and Outlook The joint project ADiFa has the goal to enable the exchange of planning data for time management in the Digital Factory through an application protocol and to simultaneously lay foundations for further application protocols. Therefore a system for unified data description is developed. The core of this system is the presented three-layered data model, which forms an essential basis for the integration of planning tools of the Digital Factory. By including universal standards, as well as PLM Services 2.0 or the STEP AP 214, a solid foundation for the data exchange will be created. The prototypical realisation of an application protocol ensues within the ADiFa framework using the example of the area of time management and of the exchange of time data. The research project ADiFa (Process Harmonisation based on Application Protocols) is supported by the German Federal Ministry of Education and Research (BMBF) within the Framework Concept Research for Tomorrow s Production and managed by the Project Management Agency Forschungszentrum Karlsruhe, Production and Manufacturing Technologies Division (PTKA-PFT). The author is responsible for the contents of this publication. 5 Citations and References 5.1 Journal Articles [1] VDI-Richtlinie 4499, Blatt 1: Digitale Fabrik - Grundlagen. Berlin: Beuth-Verlag [2] Petzelt, D.; Schallow, J.; Deuse, J.; Rulhoff, S. : Anwendungsspezifische Datenmodelle in der Digitalen Fabrik. In: ProduktDaten Journal 16 (2009) 1, S [3] Anderl R, Trippner D. STEP Standard for the Exchange of Product Model Data. B.G. Teubner Stuttgart Leipzig 2000, S [4] Deuse, J, Petzelt, D.; Schallow, J.; Reinhart, G.; Wiedemann, M.; Magenheimer, K.: Anwendungsprotokoll zur Prozessharmonisierung in der Digitalen Fabrik. In: Zeitschrift für wirtschaftlichen Fabrikbetrieb 104 (2009) 1-2, S [5] ISO Industrial automation systems and integration - Product data representation and exchange - Part 214: Application protocol: Core data for automotive mechanical design processes. Berlin: Beuth-Verlag Internet References [6] Product Lifecycle Management (PLM) Services 2.0. Available at: < >. Accessed on: Feb. 16 th [7] PLM XML Available at: < Accessed on: Mar. 24 th 2010.