Ricerche applicate sul controllo e la gestione del workflow produttivo Cesare Fantuzzi Universita’ di Modena e Reggio Emilia Facolta’ di Ingegneria Reggio Emilia Automazione Industriale

Production Workflow Production Workflow e’ il flusso che un manufatto (prodotto industriale, documento, etc.) segue all’interno di un processo produttivo per la sua trasformazione/elaborazione in un prodotto finito. Production Workflow: Strutturazione dei compiti (task) di produzione. Identificazione degli attori (macchine/umani) che sovraintendono ai tasks. Ordinamento/sincronizzazione dei tasks. Elaborazione dell’informazione (controllo, supervisione, acqusizione dei dati di produzione) per la gestione dei tasks. Workflow at its simplest is the movement of documents and/or tasks through a work process. More specifically, workflow is the operational aspect of a work procedure: how tasks are structured, who performs them, what their relative order is, how they are synchronized, how information flows to support the tasks and how tasks are being tracked. As the dimension of time is considered in Workflow, Workflow considers "throughput" as a distinct measure. Workflow problems can be modeled and analyzed using Petri nets. While the concept of workflow is not specific to information technology, support for workflow is an integral part of document management and imaging software. Distinction can be made between "scientific" and "business" workflow paradigms. While the former is mostly concerned with throughput of data through various algorithms, applications and services, the latter concentrates on scheduling task executions, including dependencies which are not necessarily data-driven and may include human agents. Scientific workflows found wide acceptance in the fields of bioinformatics and cheminformatics in the early 2000s, where they successfully met the need for multiple interconnected tools, handling of multiple data formats and large data quantities. Also, the paradigm of scientific workflows was close to the well-established tradition of Perl scripting in life-science research organizations, so this adoption represented a natural step forward towards a more structured infrastructure setup. Business workflows are more generic, being able to represent any structuring of tasks, and are equally applicable to task scheduling within a software application server and organizing a paper or electronic document trail within an organization. Their origins date back to the 1970s, when they were purely paper-based, and the principles from that period made the transition to modern IT infrastructure systems.

Un esempio: Linea di produzione Tetra Pak Un esempio di production workfow: linea di impacchettamento Tetra Pak. Il task consiste nella produzione di pacchetti contenenti liquido alimentare.

Production workflow. Packaging line control Production batch scheduling Packaging Line Monitor System (PLMS) Quali sono le interazioni tra il sistema informativo e il production workflow? La schedulazione dei batch di produzione. Il sistema di controllo delle singole macchine e il controllore di linea. Il sistema di supervisione e raccolta dati

I temi di ricerca applicata per il workflow produttivo Metodologie per descrivere ed organizzare il workflow produttivo (progetto del processo). Nuove tecnologie IC (Information & Communicario) per la gestione del workflow produttivo (controllo del processo) Tools per l’analisi del workflow produttivo (analisi del processo).

1. Organizzazione del workflow produttivo Nuove metodologie di progetto per un workflow process complesso (industriale, business, software oriented, etc.). Uso di diagrammi logici visuali: Reti di Petri. Activity Diagram di UML

Consentono di descrivere il flusso della produzione. Diagrammi di stato (Reti di Petri) per la descrizione di un Process Workflow Consentono di descrivere il flusso della produzione. Questi diagrammi sono molto utili in fase di progetto e alla analisi. Permettono di mettere in evidenza criticita’ progettuali. The application of Petri nets to workflow management. van der Aalst, W.M.P. In: Journal of Circuits, Systems and Computers, Vol. 8, No. 1, pages 21-66. 1998. Workflow management promises a new solution of an age-old problem: controlling, monitoring, optimizing, and supporting business processes. What is new about workflow management is the explicit representation of of the business process logic which allows for computerized support. This paper discusses the use of Petri nets in the context of workflow management. Petri nets are an established tool for modeling and analyzing processes. On the one hand, Petri nets can be used as a design language for the specification of complex workflows. On the other hand, Petri net theory provides for powerful analysis techniques which can be used to verify the correctness of workflow procedures. This paper introduces workflow management as an application domain for Petri nets, presents state-of-the-arts results with respect to the verification of workflows, and highlights some Petri net based workflow tools.

Diagrammi di stato e di flusso (UML Activity diagram) per la descrizione di un Process Workflow Come le reti di Petri permettono di analizzare workflow complessi. Disponibili molti tools software di analisi (ref. www.uml.org )

2. Gestione del workflow produttivo Il controllo del processo produttivo organizzato su flussi di produzione richiede l’utilizzo estensivo di strumenti ICT (Information Communication Technology). Ler ricerche sono rivolte verso lo sviluppo di strumenti ICT per: Scheduling della produzione in batch. Controllo remoto delle isole produttive con ottimizzazione dei percorsi (re-routing in caso di blocchi). Raccolta dei dati di produzione.

La ricerca nel settore del controllo del production Workflow. Technologies for Business Processes (TBP) and Integration in Manufacturing (IiM) . Decine di progetti di ricerca sviluppati da consorzi europei (ricerca finanziata) http://www.cordis.lu/esprit/src/projlist.htm

Alcuni esempi PLENT: PLanning small medium Enterprise NeTworks. Sviluppo di software tools per mettere in comunicazione i sistemi informativi di PMI che gia’ collaborano in un process workflow. VIVE: Vertical VIrtual Enterprise. E-commerce per PMI che collaborano in un process workflow. FLUENT: Flow-oriented Logistics Upgade for Enterprise NeTworks.: Sviluppo di software tools per la la gestione del flusso logistico in un network di PMI. 20723 PLENT Planning Small Medium Enterprise Networks http://www.cordis.lu/esprit/src/20723.htm The PLENT project is performed by a consortium of seven independent partners and four associated partners of three EU countries: Italy, Spain and Greece. A Hungarian partner has jointed the consortium to expand and generalise the experience. The co-ordinating partner is Democenter, an Italian non-profit organisation comprised of several manufacturing SMEs and representing the most important regional enterprise associations and local administrations. The project will develop a set of innovative software tools to support co-ordinated planning in networks of autonomous small and medium sized manufacturing enterprises. In this context, the most important problem is not the study of a sophisticated decision-making technique but the definition of a planning policy that is based on well defined, completely visible and strictly applicable rules. This is necessary to remove the historical distrust between enterprises traditionally in competition with each other, so as to reach the needed degree of confidence in the network organisation. The project is subdivided into three main phases: network planning; software design, development and testing; system validation and tuning. The first experiment, carried out with the Italian network, aims at verifying the basic planning functionalities in an already constituted organisation. The second experiment, carried out within the Spanish network, aims at verifying the system's capability of coping with frequent interactions caused by duration variability of complex product phases. The third experiment, carried out by the Greek network, aims at verifying the global system performance with respect to a highly reconfigurable network. The project results will be exploitable in three ways: via the user partners, mainly interested in extending the respective networks to increase offer variety and production capacity; via the intermediate users by promoting the adoption of this organisational paradigm by enterprise networks to be created; via the software developer by incorporating the resulting package into its software product line. 26854 VIVE Vertical Virtual Enterprise http://www.cordis.lu/esprit/src/26854.htm, New market opportunities and product innovation require financial and technical ability that individual SMEs are rarely equipped to face, and as a consequence, they can benefit from working together to cover all the required business functions, through the creation of a “Virtual Vertical Enterprise ”. The VIVE project will facilitate the creation of SME virtual enterprises (VE), by delivering methodologies and technologies. It aims to create, A new entity, the “Business Integrator “, that will be able to, Identify market opportunities; Simulate and specify the required business processes, the enterprise integration infrastructure, the required skills and capacities; Solicit and support suitable SMEs to enter the VE; SMEs, that will be able to re-engineer their processes to join the VE using VIVE adapted ICT solutions. 29088 FLUENT Flow-oriented Logistics Upgade for Enterprise Networks The project aims to design, implement and experiment a new IT solution for managing complex logistic flows, occuring in a distributed manufacturing network with multiple plants and co-operating firms. Networks of this kind are gaining relevance today as the result of (1) emerging virtual/extended enterprise paradigms; (2) pull-oriented production models, like Just-In-Time, requiring synchronisation of internal and external flows; (3) lean/agile manufacturing models, based on horizontal, goal-oriented process chains; and (4) evolving market conditions, calling for business globalisation and decentralisation of manufacturing facilities. In response to these changes, FLUENT project will provide manufacturing companies advanced IT tools for logistics decision-making, to enhance their capability to operate in a distributed production environment. In particular, the project will offer the following benefits to end users, Improved control of suppliers and sub-contractors, resulting from (1) better synchronisation between supply and production and between the suppliers themselves; (2) increased reactiveness to changes and unexpected events; (3) optimisation of workload distribution, through advanced decision-making techniques; Improved relationship with customers, resulting from (1) more accurate estimations; (2) improved offer qualification in terms of functional specifications, capacity and performance; (3) improved customer support, through timely and formal communication throughout the business relationship; Increased potential for co-operation, resulting from (1) network-level visibility, including co-operation possibilities and available partners; (2) clear definition of roles and responsibilities between the nodes; (3) support to different forms of co-operation, to comply with each node disposition and needs. To meet these objectives, FLUENT intends to develop an advanced IT infrastructure based on the following, A standard Communication and Workflow Infrastructure, that provides basic data interchange and message services and can be easily accessed and configured to realise higher level functionalities; A high-level Network Model, constructed on top of this basic layer; An Active Flows Control (AFC) component, which monitors interaction with nodes in the Network Model; A Performance Measurement System (PMS), acting in parallel with the AFC; Two Decision Support Sub-systems (DSS), respectively for input and output flows management; An Interface to Enterprise Resource Planning (ERP) systems that allows transparent interaction with the node local production management. Up to now, immature solutions have been developed in this field, still too much dependent on a specific ERP platform, industrial sector or organisation model, and thus failing to achieve above listed requirements. FLUENT by integrating logistics decision-making, ERP and workflow management into a flexible architecture, has a high potential for penetration in the market segment currently occupied by Supply Chain Planning (SCP) software, thanks to its innovative features.

3. Analisi del workflow produttivo Analisi dei dati di un workflow process per la sua ottimizazione. Il progetto: ottimizzare il throughput produttivo di una linea di impacchettamento Tetra Pak. Partners: Tetra Pak – Facolta’ di Ingegneria, Reggio Emilia

Il progetto di ricerca. Ogni macchina è soggetta ad inceppamenti che sono in grado di interrompere il flusso produttivo della linea e causare di conseguenza il blocco di altre macchine. Si utilizzano quindi degli accumulatori di prodotto (buffer) che disaccoppiano le macchine garantendo una certa continuità di funzionamento. Lo scopo del progetto e’ la determinazione della configurazione ottimale dei buffer lungo la linea di produzione.

Ottimizzazione di una linea di produzione Plant Master planning schedule Forecasts, orders, budget Produ ction sched ule Setups Line operation Breakdowns Saleable production Idle, speed Waste …………… Shop floor System performance Line performance

Un modello matematico della linea B1 p1, r1, 1 p2, r2, 2 N1 M3 B2 p3, r3, 3 N2 Mm Bm-1 pm, rm, m Nm-1 ……… Mu(1) Md(1) B(1) pu(1), ru(1), u(1) pd(1), rd(1), d(1) L(1) Mu(2) Md(2) B(2) pu(2), ru(2), u(2) pd(2), rd(2), d(2) L(2) Mu(m-1) Md(m-1) B(m-1) pu(m-1), ru(m-1), u(m-1) pd(m-1), rd(m-1), d(m-1) L(m-1) ………………………

Risultati della ricerca Determinazione di: Posizionamento ottimo dei buffer. Dimensione ottima dei buffer. Calcolati in base a modelli matematici della linea e del comportamento statistico dei fermi macchina. I risultati teorici sono in attesa di conferma sperimentale (simulazioni su modelli funzionali)

Ulteriori info: cesare.fantuzzi@unimore.it Bibliografia Marlon Dumas and Arthur H.M. ter Hofstede , UML Activity Diagrams as a Workow Specfication Language, in UML 2001 Conference, Toronto (Canada). van der Aalst, W.M.P. , The application of Petri nets to workflow management, Journal of Circuits, Systems and Computers, Vol. 8, No. 1, pages 21-66. 1998. A. Grassi e C. Fantuzzi, Modellazione del comportamento prestazionale delle linee di produzione, DISMI, rapporto interno. Ulteriori info: cesare.fantuzzi@unimore.it