Systems Engineering Framework to Support Maintenance Systems M. Messaadia1, A.E.K Sahraoui2, K.-D. Thoben3, C. Hans3 1

LAAS-CNRS , Rue du Colonel Roch 07,31077 Toulouse, France [email protected] 2

IUT-B University of Toulouse, Le Mirail, France, [email protected]

3

BIBA, Hochschulring 20, 28359 Bremen, Germany, {tho, han}@biba.uni-bremen.de

Abstract The paper is on integrating product design and support system through the EIA systems engineering standard. The support sub system concerned is the maintenance process. We show in this work how to link effects and decision analysis results from the maintenance system on the final product system and the associated production subsystem. Such effect can be either to modify the requirements influencing the design for the product or to improve/change the production system technology or layout with respect to machining/assembling operation. Keywords System Engineering, Maintenance, Product Lifecycle Management.

1

Introduction

Usually a development process is starting with the requirements analysis. It aims to develop the needs to be fulfilled by a product or service in order to ensure its correct operation and to manage those requirements throughout the development cycle. Nowadays – as products or services become more and more complex – the Systems Engineering (SE) methodology is often applied in order to deal with this complexity. Originally Systems Engineering was conceived in the 1960’s to solve issues resulting from the increasing complexity of products developed in the space industry. Currently industry is again introducing and adapting SE, which describes an example of a “SE integrated development framework” [Sahraoui, Buede, Sages, 2004]. Here SE has been chosen to overcome the obstacles of current Concurrent Engineering environments [Lardeur, Auzet, 2003] by focusing on components maintenance. The vision for future manufacturing is that more and more organisations will have to adopt an agile mindset in managing relationships to find world-class customer and supplier partners. In this context, manufacturing businesses will have to make continuous reassessments of their core strengths and competencies. Today’s customer-driven markets force companies to increase their focus on high-added-value products and technologies, yet at the same time broaden the total service spectrum within which these are brought to market. Such objectives are based on initial requirements that are linked to the type of processes and the flexibility of product to be manufactured. Here Systems Engineering represents a suitable approach as all processes are considered while at the same time a focus can be put on the specific link between the support (maintenance) being part of enabling product and the final product. Following this approach though is to make modular decomposition and making abstraction of details of such modules/systems. The decomposition through the SE standard gives an opportunity to apply corresponding best practices. The approach presented in this paper considers the maintenance systems engineering which is supposed to affect the requirements. To increase the quality of products, earlier practices on co-

ordination between products and related maintenance systems engineering have to evolve, in order to improve the product development by returning the “lessons learned” throughout the maintenance activities back into the development process. At the same time maintenance is affected by high level requirements such as business and strategic requirements as well as technical and systems requirements. Considering all of them while addressing continuous improvement of product quality requires a novel approach for maintenance design; such an approach as discussed in the remaining of the paper is highly based on Systems Engineering in terms of processes, methods, tools and associated standards.

2

Systems Engineering issues and concepts

In the context of this paper Systems Engineering can be considered as the application of scientific and engineering efforts to: •

Transform an operational need into a description of system performance parameters and a system configuration through an iterative process of definition, synthesis, analysis, design, test, and evaluation.

•

Integrate reliability, maintainability, expandability, safety, survivability, human engineering and other factors into the total engineering effort to meet cost, schedule, supportability, and technical performance objectives. Thus Systems Engineering represents an interdisciplinary approach that: •

Encompasses the scientific and engineering efforts related to the development, manufacturing, verification, deployment, operations, support, and disposal of systems products and processes.

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Develops needed user training, equipment, procedures, and data.

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Establishes and maintains configuration management of the system.

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Develops work breakdown structures and statements of work and provides information for management decision making [Messaadia, Jamal, Sahraoui, 2005]. Applying the SE practice is illustrated by Figure 1. Following this paradigm a system is decomposed initially into the end product (the operating system itself) as well as all enabling products covering the production, testing, deployment or the support of the end product.

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O p e ra tio n a l P ro d u c ts ••• End P ro d u c t

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S u p p o rt P ro d u c ts

Figure 1: Product and enabling products structuring

The end product can be decomposed into further subsystems. Afterwards these subsystems are decomposed into end product and enabling products and this refinement process will follow until we obtain elementary parts or component on the shelf (COTS).

Figure 2 shows that some subsystems or products are refined and some others are not refined as they exist already: For instance a PC computer is an end product that doesn’t need to be refined since it is a COTS system [Jamal, Sahraoui 2005]. U s e r o r C u s to m e r D e s ire d S y s te m

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Figure 2: System development structure

In SE it is a good practice to describe processes adopting the EIA standard (see Figure 3 below). There are thirteen processes covering the management issues, the supply/acquisition, design and requirement and verification validation processes [EIA632 Standard, 1998]. T e c h n ic a l M a n a g e m e n t P la n n in g P ro c e s s P la n s , D ir e c t iv e s & S ta tu s

A ssessm ent P ro c e s s

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R e q u ir e m e n ts D e fin itio n P r o c e s s S o lu tio n D e fin itio n P ro c e s s D e s ig n s P ro d u c t R e a liz a tio n Im p le m e n ta tio n P ro c e s s T r a n s itio n to U s e P ro c e s s P ro d u c ts T e c h n ic a l E v a lu a t io n S y s te m s A n a ly s is P ro c e s s

R e q u ir e m e n ts V a lid a t io n P ro c e s s

S y s te m V e r ific a tio n P ro c e s s

E n d P ro d u c ts V a lid a t io n P ro c e s s

Figure 3: System engineering process

•

Technical management processes (three processes): these processes monitor the whole process ranging from the initial idea to build a system till the system delivering

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Acquisition and supply processes (two processes): these processes ensure the supply and acquisition (and are very close to logistics)

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System design processes (two processes): these processes are on the elicitation and acquisition of requirements and their modelling, the definition of the solution and its logical design.

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Product realization processes (two processes): theses processes deal with implementation issues of system design and its use.

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Technical evaluation processes (four processes): theses processes deal with verification, validation and testing issues. These categories support an adequate and complete description of the underlying processes to be considered for the following steps.

3

From SE to maintenance: the framework

Along the Systems Engineering view maintenance is seen as a further subsystem. Figure 4 shows the link to this subsystem.

Figure 4: Maintenance system via ES

The tree structure resulting from the decomposition of the processes as shown above gives an overview concerning the end product (here maintenance) as well the associated enabling products to be considered here. Within Figure 4 the enabling products/components comprises tests, persons tools etc and some others.

3.1

Linking the end product and enabling product

The connections of an end product with its enabling products allow planning and control of the engineering. The manufacturing mission of the production system is the source of the connection. This link is refined when the engineering of the product or the maintenance system is performed. As soon as the architectures are found, this link becomes a relation between defined systems and targeted deliverable exchange (still not valued) could be planned. The link enables to optimize concretely the simultaneous engineering of product and related maintenance systems.

Exchange of valued information must occur between the distinct technical tasks of each system. For instance, solutions of product design are taken as constraints for the maintenance system requirements analysis. Solutions of maintenance system design are taken as constraints for product requirements analysis.

R e q u ire m e n t

P ro d u c t (Y + 1 )

M a in te n a n c e (Z + 1 )

S y ste m P ro d u c tio n (X + 1 ) M a in te n a n c e (Z ’+ 1 )

Figure 5: From requirement to maintenance

Concrete values must be considered here, because they induce feasibility and delay constraints. Essential contribution of enabling product design for the design of the end product is located in requirements engineering, as described in [EIA632 Standard, 1998]. We can confirm this point of view: requirements analysis of the end product brings the source of information required by each of the enabling products. In the context of this paper, the maintenance system monitors the product behaviour. Following the observations will be introduced to improve the reliability of the final product. We see in this example that only PLM ensures that the linkage is carried out between the enabling product (manufacturing, maintenance) and final product. Of course this can be applied only in the case of applying system engineering concept: distinction between final and enabling product as illustrated by Figure 5.

3.2

PLM: Product Lifecycle Management

More commonly referred to as PLM – is emerging as the new method for industrial companies to better manage product development and “in-service” processes from beginning to end in the product lifetime (cf. Figure 6).

Manufacturing Engineering Product Engineering

Manufacturing And production Sales And distribution

Info System

Concept engineering And prototyping

Maintenance And repair

Requirement analysis And planning

Disposal And recycling

Figure 6: PLM information system context

PLM is a systematic, controlled method for managing and developing industrially manufactured products and related information. PLM offers management and control of the production (development and marketing) process and the order-delivery process, the control of product related data throughout the product life cycle, from the initial idea to the scrap yard. Almost without exception, the PDM and PLM abbreviations also refer to a data system developed to manage product data [Saaksvuori, Immonen, 2004]. In basic terms, PLM involves the use of digital software to eliminate much of the costly trial and error that has plagued manufacturers since the industry took a step beyond the industrial revolution [Bodington et al, 1999]. PLM is seen as an information system; Product Lifecycle Management systems control critical product information that must be shared with other enterprises and enterprise systems such as ERP, CRM and SCM. This bi-directional connection between PLM and other systems is critical to enable a seamless flow of information among the different functional groups involved in product development, particularly engineering and manufacturing [Messaadia, Jamal, Sahraoui, 2005]. A comprehensive approach means that many organizations and individuals must collaborate in the process. Because this collaboration spans different levels of the organizations involved, the solution requires seamless integration between the project information and the product information in order to support coordinated, collaborative business processes. The organizations and individuals to be linked together are both internal (marketing, legal, advertising R&D, production, etc.) and external (testing labs, outsourced production, ad agencies, etc.) [Terzi, 2005].

4

An example

We adopt the linking approach for bicycle production and focus on PLM. The bicycle is the final product in SE taxonomy and we try to apply such framework for a bicycle manufacturing project by enhancing PLM processes as an information system. The manufacturing is a part of the life cycle of the product which is covered by the PLM containing the processes of manufacturing of the product. In our example the end products of subsystems would include things like the wheels, the handlebars, and the frame.

System System(Y) (Y)

Bicycle Bicycle(Y) (Y)

Well Well

Development Development

Production Production Product Product(X) (X)

Frame Frame

Chain Chain

Training Training Product Product

Test TestProduct Product

Disposal Disposal Product Product Support Support Product Product

Deployment Deployment Product Product

PLM

Pedals Pedals Adding Spring

System System(Y+1) (Y+1)

Bicycle Bicycle (Y+1) (Y+1)

Well Well

Chain Chain

Development Development

Production Production Product Product(X+1) (X+1)

Frame Frame

Pedals Pedals

Test TestProduct Product

Training Training Product Product

Deployment Deployment Product Product

Spring Spring

Disposal Disposal Product Product

Support Support Product(X+1) Product(X+1)

Linkage Flow New requirement

Figure 7: Bicycle frame linking processes

Each association between product and the corresponding enabling product set can be managed as a connection between systems of each hierarchical system structure. In the example of the bicycle we can see the process of manufacturing, which defines the manufacturing of all parts of the bike until the end product. Whenever a new requirement is emitted - which is for example to add a spring in the frame of the bicycle - this decision is managed by the PLM system. Firstly it is transferred via the PLM towards the team from engineering which will use it in order to define the impact of this modification as well as the system for production taking care for the change of the manufacturing processes. The PLM will be also given the responsibility to safeguard and bring up to date the new product and its manufacturing process (cf. Figure 7).

5

Conclusions and perspectives

A preliminary approach for PLM used as a tool for linking both the development of the product and the development of enabling products (maintenance), has been presented. Such approach is highly based on a systems engineering framework for manufacturing systems. Perspectives forward are planned to refine this approach for maintenance process as enabling support product and the development of a tool. References A.E.K.Sahraoui, D.M.Buede, A.P.Sages:Issues for systems engineering research, 14th Annual International Symposium INCOSE 2004, Toulouse (France), 11p, 20-25 June 2004,. E. Lardeur, C. Auzet: Deployment of SE including Manufacturing Systems development: Practical Aspects . The 13th annual International Symposium INCOSE 2003, INCOSE, Washington, DC, USA.2003. M. Messaadia, M.H. Jamal, AEK. Sahraoui: Systems Engineering Processes Deployment for PLM. International Conference on Product Lifecycle Management (PLM'05), pp.282-291, 11-13 July 2005. M.H. Jamal AEK. Sahraoui, Customising systems engineering concepts: case study on concurrent engineering Context. ESEC, European symposium on concurrent engineering systems, Toulouse April 2005. EIA Standard processes for Engineering a System 1998: EIA- 632-1998 On-line Reliability Engineering Resources for the Reliability Professional http://www.weibull.com

A. Saaksvuori and A. Immonen: Product lifecycle Management, Springer-Verlag Berlin. Heidelberg 2004. R. Bodington et al: Product Data Sharing in Virtual enterprise 1999. S. Terzi, : Elements of Product Lifecycle Management Definitions, Open Issues and reference Models . PhD thesis politecnico di milano, Italia. 2005.