Production Activity Control System Research Articles

Intelligent and collaborative Multi-Agent System to generate and schedule production orders

The authors present a Multi-Agent System for constructing and releasing production orders. In a manufacturing enterprise, the generation of production orders consists in a set of coordinated tasks among departments. This has been achieved traditionally as a module of the Production Activity Control (PAC) system. However, classic PAC modules lack collaborative techniques and intelligent behaviour. Moreover, in real-life situations experienced planners take over traditional PAC systems, since the range of possibilities to actually build production orders increases exponentially. To contribute to production planning, we present an intelligent and collaborative Multi-Agent System (MAS), having coordinated two forms to emulate intelligence. The learning capability is achieved by means of a Feed-forward Artificial Neural Network (FANN) with the back-propagation algorithm. The FANN is embedded within a machine agent whose objective is to obtain the appropriate machine in order to comply with requirements coming from the sales department. Also, an expert system is provided to a tool agent, which in turn is in charge of inferring the right tooling. The MAS also consists of a coordinator and a spy. The coordinator agent has the responsibility to control the flow of messages among the agents, whereas the spy agent is constantly reading the Enterprise Information System. Finally, a scheduler agent schedules the production orders. The resultant MAS improves the current form to plan production in a factory dedicated to produce labels.

A multi-agent system to construct production orders by employing an expert system and a neural network

The authors describe the implementation of a multi-agent system, whose goal is to enhance production planning i.e. to improve the construction of production orders. This task has been carried out traditionally by the module known as production activity control (PAC). However, classic PAC systems lack adaptive techniques and intelligent behaviour. As a result they are mostly unfit to handle the NP Hard combinatorial problem underlying the construction of right production orders. To overcome this situation, we illustrate how an intelligent and collaborative multi-agent system (MAS) obtains a correct production order by coordinating two different techniques to emulate intelligence. One technique is performed by a feed-forward neural network (FANN), which is embedded in a machine agent, the objective being to determine the appropriate machine in order to fulfil clients’ requirements. Also, an expert system is provided to a tool agent, which in turn is in charge of inferring the right tooling. The entire MAS consists of a coordinator, a spy, and a scheduler. The coordinator agent has the responsibility to control the flow of messages among the agents, whereas the spy agent is constantly reading the Enterprise Information System. The scheduler agent programs the production orders. We achieve a realistic MAS that fully automates the construction and dispatch of valid production orders in a factory dedicated to produce labels.

Development of an automated process planning and production activity control system for the manufacturing of engineered work surfaces

This paper describes the design and implementation of an Automated Process Planning and Production Activity Control system for a make-to-order business and presents a formal methodology for the development of integrated manufacturing systems. The research is based on concepts developed in a project undertaken in a job shop Case Study facility, producing precision-engineered work surfaces. Industry today is facing numerous challenges on many fronts demanding improved availability and dissemination of processing information. On the demand side there is increased pressure on the manufacturer to meet deadlines and provide the customer with a prompt, efficient service, with accurate lead-time information, and a product of the utmost quality, on time. On the supply side there is increasing competition, variety in the market, a diverse product range, varying processing times and extremely short lead times. The nature of today's business world means that real-time information is a requirement and not an extra. This paper documents the design, structure and implementation of an Automated Process Planning system, which completely automates and integrates Order Entry stages from order receipt to order release. The developed system, namely the Manufacturing Optimization Information System, or MOIS, relays information to and from shop floor operators via a Production Activity Control system at each of the manufacturing stations. The MOIS is part of ongoing research endeavouring to integrate order processing, Process Planning and production control activities with a combined dynamic scheduling and material optimization module in a holistic manufacturing optimization system. The two specific aims of this paper are very clear; first, to bridge the theory-practice gap between theoretical concepts and real industrial issues surrounding Process Planning and Production Control. Secondly, to outline the design, structure and evolution of an integrated Automatic Process Planning and Production Activity Control system, installed in a make-to-order enterprise.

Hybrid production control approach for JIT scheduling

A distributed production activity control system has been developed in the LAMIH laboratory to solve several problems inherent in the inflexibility of classic centralized production activity control systems. The distributed approach implies local decision making and real time control for task allocations. This forbids correct forecast on critical information such as time cycle for each manufacturing order, meaning a lack of viability for industrial application. The aim of our work is to provide a structure which takes advantage of both extrema and which is able to support just-in-time concepts: the hybrid production activity control structure. The hybrid approach uses the notion of bottleneck and non-bottleneck resources and is based on the distributed control structure developed in the laboratory. The bottleneck is the only resource scheduled. It forces the synchronicity of the whole production structure because of its characteristics. This paper evaluates the relative performances of the three control structures (centralized, distributed and hybrid) through theoretical discussions and practical examples from a simplified industrial case study.

Reference models and object-oriented method for reuse in production activity control system design

The design of the Production Activity Control system (PAC) of a manufacturing system is a costly and difficult task since it must be adapted to the workshop characteristics and to its environment. Reuse of past experiences and integration of commercial software is a key issue in order to improve the PAC system quality, and in order to decrease the cost and time of its development. In order to fulfil these requirements two types of tools are necessary: reference models to structure the organisation of the PAC system and software engineering tools to build the PAC system. The object-oriented methods are good candidates to realise the latter since they are recognised as providing efficient support in order to shorten the code development phases. Moreover, they allow to develop modular and reusable software. Nevertheless, most of the applications developed in the past years focused on very low level control structure design, and there is still a lack in supporting tools for the design of complex production activity control architectures. In this paper, we suggest to define modular reference models of PAC modules in order to provide a structuring framework for PAC system organisation specification. Then we use adapted object-oriented techniques to derive the PAC organisation description into a real PAC system. An example, based on a real workshop of AEROSPATIALE and using the FUSION method, is provided.

A decision support system for production activity control

The increase of manufacturing system flexibility makes variations in routings, operations, machines or operators possible. These degrees of freedom may be used at the Production Activity Control (PAC) level in order to react to unpredictable events such as machine failures, absence of operators or changes in the workshop environment. In order to manage these degrees of freedom, we suggest a Decision Support System that should make the choice of solutions easier in order to reduce the consequences of a failure. This DSS complements the scheduling module of the PAC system since it may be used, either in order to slightly modify an existing schedule, or to choose the scheduling hypothesis. This DSS uses fuzzy logic and theory of possibility because of the imprecision and uncertainty of the information managed, first to model the objectives, then to spread the expected consequences of an imprecisely known event. The DSS has successively been prototyped with the SuperCard™ environment on a Macintosh microcomputer, then with the Oracle™ data base on a Sun Sparcstation.

A conceptual framework for shopfloor production activity control

Abstract It is now recognized that production activity control (PAC) is a key factor of productivity. Some aspects of this theme, such as scheduling of production operations or shopfloor monitoring, have been the subject of extensive research and solutions are now available and regularly used in industry. In spite of this, PAC remains a complex activity for which no generic solution is available. In this paper, we suggest a conceptual framework for PAC which aims to provide support for the choice and integration of the various components of a PAC system. Several types of PAC modules are suggested and have to be chosen and organized in relation to the workshop characteristics. This proposal is supported both by a bibliographic study of current approaches and by the requirements expressed in AEROSPATIALE'S shopfloors.

Project 477: pilot implementation of a production activity control (PAC) system in an electronics assembly environment

Abstract Abstract, Production activity control (PAC)is concerned wkh the short-term planning and execution of manufacturing orders in the production process. The aims of ESPRIT project 477, entitled 'Control Systems for Integrated Manufacturing' were to develop a generic PAC architecture and software tools to support the design and implementation of PAC systems. This paper outlines the PAC architecture and development principles, and describes the first pilot implementation of a PAC system in the Digital electronics assembly facility at Clonmcl, Ireland. The paper introduces the PAC architecture and highlights the importance of PAC in a computer integrated manufacturing environment. The development cycle for PAC systems is described, and reference made to the PAC simulation model which was used for validating the architecture. The main emphasis of this paper is on the pilot implementation of PAC in a live manufacturing environment. The rationale for a PAC pilot implementation is explained, and the pilot p...

The monitor in production activity control systems

Abstract Effective control of manufacturing processes depends on accurate, timely recording of data from the shop floor. Data collected as result of this is translated into information which may be the basis for real-time control or later management decisions. Thus there is a need for a data capture and analysis mechanism which operates reliably, quickly and accurately. This mechanism is called the monitoring function. The monitoring function comprises of three distinct elements, namely: data capture; data analysis and decision support. The data capture system collects all the relevant information from the shop floor and then this is ‘massaged’ by the data analysis mechanism to produce real-time and historical reports which aid the decision making process in the manufacturing system. This paper outlines the development of a software tool for the control of the manufacturing operation at the operational level (i.e. quasi real-time) and describes in detail the development and use of software modules to supp...

Production activity control—a key aspect of production control

This paper reviews the role of Production Activity Control (PAC) in modern production and inventory management systems. It argues that the PAC system is fundamental to the realisation of computer integrated manufacturing (CIM) at the operational or shop floor level. It presents an architecture for PAC and suggests that to date research has overemphasised one element of PAC, namely the scheduling function, and further has considered scheduling as an isolated problem without reference to the overall PAC system requirement. This, along with the tendency to consider scheduling as a combinatorial problem to be solved using mathematically elegant techniques accounts for the ‘theory-practice gap’ in scheduling. The paper concludes with some suggestions for further research effort in the PAC area.