An integrated methodology for manufacturing systems design using manual and computer simulation

Traditional approaches to manufacturing systems design utilize a sequential procedure that focuses on production capacity requirements, with human operator task design developed late in the systems design phase. Implementing manufacturing systems in this way is difficult when operations management must design flexible and efficient processes, with an often incomplete understanding of how people can best perform within the system. This study developed an integrated methodology that uses both manual and computer simulations to evaluate system performance and ergonomic issues early in the system design process. Information about operator performance and ergonomics is obtained in the manual simulations, while estimates of operator utilization and system throughput is obtained through computer simulations. An iterative design process is used, with the results of manual and computer simulations informing each other during subsequent simulations. An industrial case study is presented here to demonstrate the effectiveness of this methodology. The results show that the methodology can be used to design manufacturing systems with significant savings in labor cost and improved manufacturing system flexibility. © 2003 Wiley Periodicals, Inc. Hum Factors Man 13: 19–40, 2003.     

Using computer controlled physical models to analyze computer integrated manufacturing systems

It is usually difficult to design and install complex computer integrated manufacturing (CIM) systems without a large amount of time spent on debugging. In many cases miniature computer controlled physical models can provide information that reduces the time spent in the design and installation of larger systems. This paper describes how miniature physical models can be used to help industrial engineers design and install CIM systems.     

Flexible manufacturing cells and systems with computer intelligence

Conditions for the introduction of flexible automated manufacturing systems have much improved. Future flexible manufacturing cells and systems will increasingly use computer intelligence. The paper describes system concepts, the design and function of components, system control and supervisory strategies. The planning and introduction of flexible automated manufacturing systems and their economical application will also be discussed.     

Design of expert systems for integrated production automation

An approach to the design of expert systems for integrated production automation is presented. The major components in an integrated manufacturing system consist of corporate planning, marketing planning, research and development, engineering design, production planning, manufacturing, warehousing, and product distribution. These components are linked by management information flow, technology information flow, as well as materials flow. An intelligent computer is used to integrate information flow and to control materials flow. This paper discusses characteristics of the future factory, elements of knowledge based systems, and the design of computer based expert systems for production planning, for engineering design, and for integrated manufacturing.     

Integrating manufacturing resources planning (MRP II) with flexible manufacturing systems (FMS)

This paper will describe the gap that exists between the Manufacturing Resources Planning (MRP II) system and the Flexible Manufacturing System (FMS) and discuss several approaches for closing the gap. Considerable effort has gone into developing and integrating the various modules in the MRP II system. The modules for business planning, production planning, master production scheduling, material requirement planning, capacity requirements planning, and shop floor control have been integrated into a comprehensive computer package for planning and controlling manufacturing. At the same time, a similar effort has been underway to develop and integrate the several subsystems of a FMS. In particular, a number of computer control systems have been developed to automatically plan and control the operations of NC machines with automated tool changers, automated material handling, and automated test and inspection equipment. Unfortunately these two efforts have proceeded relatively independently with little interaction between the two groups. If computer integrated manufacturing (CIM) is to become a reality, the resulting gap must be closed, and closed rapidly.     

Planning and scheduling in new computer supported production contexts

New production concepts rely on the active (co-) shaping of planning, control and organisation processes on the shop floor level. Established CAPM technologies (CAPM =Computer Aided Production Management) only provide insufficient support, and a complete automation of the production management is not suited to close this gap. This is why new principles of system design have to be developed which meet various requirements: from taking into account a multidimensionality and contradiction of planning targets and the integration of learning opportunities with the use of systems up to the promotion of work process knowledge.     

Transitioning from tactical to strategic planning in computer integrated manufacturing

This paper describes a strategic manufacturing planning software system which is presently being developed to guide the planning, development and absorption of computer integrated manufacturing within manufacturing operations.     

Integrated decision support and expert systems in a computer integrated manufacturing environment

In a computer integrated manufacturing (CIM) environment, well planning, control and operational process require both expert knowledge of the area, and powerful decision support capabilities. This paper discusses the features of decision support systems and expert systems, and their integration to support the major functions from marketing and strategic level considerations to manufacturing operational planning and process. From the hierarchical structure of information flow in a company, this paper attempts to find the best way of combining decision support systems with expert systems in enhancing the planning, control and operational functions in a CIM environment.     

A PDES/STEP-based model and system for concurrent integrated design and assembly planning

Product data exchange and interfacing between different CAD/CAM systems are of great importance to the development of concurrent integrated design environments and computer integrated manufacturing systems. This paper presents a STEP-based method and system for concurrent integrated design and assembly planning. An integrated object model for mechanical systems and assemblies is first defined by a hierarchy of structure, geometry and feature. The structure is represented as a component-connector or joint multi-level graph with both hierarchical functional and assembly relations. These hierarchical relation models are then used for uniformly describing their causal relations both for assembly level and feature based single part level. The generic product assembly model is organized according to STEP, using mostly the entities of integrated resources and partly self-defined entities, which are necessary for design and assembly planning. Based on the generic product assembly model, STEP-based strategies and agent concepts are used for agent-based concurrent integration of design and assembly planning. A prototype system, consisting of a CAD system, a product modeling system, an assembly planning system, and an assembly evaluation system is developed, in which product data can be exchanged between these subsystems. Details about the implementation of the system are addressed. The integrated design and assembly planning system can support the introduction of a new product. The results of assembly planning are feedback to the stage of assembly design to improve on the design. A case study is carried out for assembly-oriented design of a gearbox, to illustrate the proposed approach and to validate the developed system.     

Simulation and graphical animation of advanced manufacturing systems

Automated production systems, known as Flexible Manufacturing Systems (FMS), offer a promising solution for the low productivity of mid-volume, mid-variety batch production. These systems consist of integrated machine modules and material handling equipment under computer control.This paper describes a general purpose discrete-event Flexible Manufacturing Systems Simulator (FMSSIM). The package is programmed in FORTRAN and is capable of simulating different configurations, material handling systems, and topologies including bidirectional tracks. The simulator checks blockage of routes due to interference of carts and simulates random failures and repairs of the various components in the system. The simulator provides the user with a wide range of priority rules to select from, and enables the user to define his own rules if required. The simulator produces reports on various vital system performance statistics and also displays the movement of parts through the system on a refreshed CRT. This simulator is a modular, user-oriented package which allows the designer to evaluate a wide range of systems with varied design parameters and select an efficient flexible manufacturing system. Some general trends in the behaviour of the flexible manufacturing systems are identified and guidelines for their design and operation are suggested.     

The ergonomics of computer aided design within advanced manufacturing technology

Many manufacturing companies have now awakened to the significance of computer aided design (CAD), although the majority of them have only been able to purchase computerised draughting systems of which only a subset produce direct manufacturing data. Such companies are moving steadily towards the concept of computer integrated manufacture (CIM), and this demands CAD to address more than draughting. CAD architects are thus having to rethink the basic specification of such systems, although they typically suffer from an insufficient understanding of the design task and have consequently been working with inadequate specifications. It is at this fundamental level that ergonomics has much to offer, making its contribution by encouraging user-centred design. The discussion considers the relationships between CAD and: the design task; the organisation and people; creativity; and artificial intelligence. It finishes with a summary of the contribution of ergonomics.     

Implementation of rule-based information systems for integratedmanufacturing

Focuses on the development of a methodology within a software environment for automating the rule-based implementation of specifications of integrated manufacturing information systems. The specifications are initially formulated in a natural language and subsequently represented in terms of a graphical representation by the system designer. A new graphical representation tool is based on updated Petri nets (UPN) that we have developed as a specialized version of colored Petri nets. The rule-based implementation approach utilizes the similarity of features between UPN and the general rule specification language used for the implementation. The automation of the translation of UPN to the rule specification language is expected to considerably reduce the life-cycle for design and implementation of the system. The application presented deals with the control and management of information flow between the computer-aided design, process planning, manufacturing resource planning and shop floor control databases. This provides an integrated information framework for computer integrated manufacturing systems     

VirMIC—一个基于Internet的IC虚拟制造环境

该文展示了一个Internet环境下的集成电路虚拟制造环境VirMIC,着重于系统的三个核心模块,即电路性能仿真与成品率优化模块、工艺线仿真与调度模块和产品决策模块,电路性能仿真与成品率优化模块,建立了一个基于OO-DCE的技术CAD环境,以这个环境为依托,通过协调效益和成品率进行了工艺流程的可制造性优化设计;工艺线仿真与调度模块,以一定的工艺流程和制造系统配置为基础,建立制造系统Petri网模型,从而进行系统性能仿真和生产调度,对制造系统的整体性能进行优化;产品决策模块以前两个模块为基础,对如何选择合作伙伴,如何在合作伙伴之间分配用户提交的制造负荷,为构成“虚拟企业”提供指导性信息,以上三个模块构成了Vir-MIC系统的功能核心。     

Structuring and configuration of CIM systems for branch-specific medium-sized enterprises

Strong international competition makes it necessary for an enterprise to reduce organizational overhead and costs. This goal can be reached by integrating of the available islands of automation. This integration would be facilitated greatly if there were a generally agreed upon architectural structure in which the software modules of the various vendors could operate. CIMOSA (computer integrated manufacturing—open system architecture) aims at providing such an architectural structure and strives to become a European standard. An important part of CIMOSA consists of the enterprise model. In this article the results of a project are described which is aimed at the validation of CIMOSA in a typical SME (small and medium-sized enterprise) environment. In a first step, the CIMOSA partial and particular models for SMEs were developed. The authors developed a coarse model of the order management and a detailed model of the future concept of the CAD/PPC interface. In order to master the increasing complexity of the planning of software systems of an enterprise, new planning methods and tools are required. Thus in the second part, an integrated approach to software system planning and selection based on CIMOSA enterprise models was developed. The underlying idea of the approach is the conversion of the planning problem into an equivalent constraint satisfaction problem. The conversion process can be accomplished fully automatically. To interconnect a real system, in a lot of cases, it is required to configure data conversion modules. In the third part, the article focuses on a configuration system which allows a straightforward configuration of the data conversion modules.     

Product platform configuration for product families: Module clustering based on product architecture and manufacturing process

Product family design utilizes platform-based modularity to enable product variety and efficient mass-production. While product platform issues have attracted much attention from both academia and industry, traditional product platform design for product families emphasized the platform-based modularity that focuses on product structure dimension (functional or non-functional) to realize cost reductions during the design stage. Both the design architecture and manufacturing process are objectives that define product family modularity (PFM). They should be closely coupled with each other for the planning and configuration of platforms. This paper focuses on the product platform configuration by recognizing and utilizing shared product modules for product families. Instead of clustering product modules only based on their design structure, this approach differentiates each product variant, and considers the inherent relationship between product architecture and processing activities. The advantage is that similar components can be grouped and produced on a shared platform, thus benefitting from lower cost and shorter production time. First, both the architecture and manufacturing information of the product variety are captured in matrix format. Then, hierarchical clustering is applied over the components to generate PFM. Finally, a set of platforms are constructed to efficiently process most components of variants.     

Design of practical optimum JIT systems by integration of computer simulation and analysis of variance

This study introduces a framework for re-design of manufacturing systems into practical optimum just-in-time systems by integration of computer simulation and analysis of variance. The conventional JIT approach is mostly applicable to static production systems and the dynamic production systems require a more practical integrated JIT approach. In addition, the re-design of existing dynamic systems into just-in-time systems must follow a practical path, which can be a cumbersome task. This means, a unique practical optimum just-in-time system that considers system's limitations and its dynamic behavior must be designed. To achieve the objective of this study, first, the actual system must be totally modeled and simulated. Second, the integrated simulation model is tested and validated by analysis of variance. Third, the optimum (most fitted) JIT design is developed and tested by modeling actual system's limitations and its dynamic behavior. The framework is applied and tested for an auto production line and a heavy rolling mill workshop.     

Color-defective vision and computer graphics displays

A color space defined by the fundamental spectral sensitivity functions of the human visual system is used to assist in the design of computer graphics displays for color-deficient users. The functions are derived in terms of the CIE standard observer color-matching functions. The Farnsworth-Munsell 100-hue test, a widely used color vision test administered using physical color samples, is then implemented on a digitally controlled color television monitor. The flexibility of this computer graphics medium is then used to extend the Farnsworth-Munsell test in a way that improves the specificity of the diagnoses rendered by the test. The issue of how the world appears to color-deficient observers is addressed, and a full-color image is modified to represent a color-defective view of the scene. Specific guidelines are offered for the design of computer graphics displays that will accommodate almost all color-deficient users     

A knowledge-based inspection process planning system for coordinate measuring machines

The coordinate measuring machine (CMM) is one of the most effective geometry inspection facilities used in manufacturing industry. To fully utilize its capabilities in a computer-integrated manufacturing (CIM) environment, we should integrate CMM with other systems and facilities. This paper presents the development of a knowledge-based inspection planner based on the fundamental principles of AI planning to integrate computer-aided design systems and CMMs. The issues involved in CAD-directed inspection process planning are examined; the task of inspection process planning is decomposed into a number of sub-tasks. According to the task decomposition, a knowledge-based planning system was designed with several modules. Each of these modules consists of a knowledge base, a control operator, a context and a communication interface. The knowledge base is the local knowledge source for problem solving; the control operator determines when and where the knowledge is applied; the context contains the initial planning state which is essential input part information, the intermediate planning states which result from the tentative decision made by the modules, and the goal state. The module interfacing was realized by directly calling procedures defined in other modules to pass the planning tasks and decisions. Examples are included to explain the planning knowledge and strategy.     

A two phase optimization method for Petri net models of manufacturing systems

Optimization is a key issue in the design of large manufacturing systems. An adequate modeling formalism to express the intricate interleaving of competition and cooperation relationships is needed first. Moreover, robust and efficient optimization techniques are necessary. This paper presents an integrated tool for the automated optimization of DEDS, with application to manufacturing systems. After a very quick overview of optimization problems in manufacturing systems, it presents the integration of two existing tools for the modeling and evaluation with Petri nets and a general-purpose optimization package based on simulated annealing. The consideration of a cache and a two phase technique for optimization allows to speed-up the optimization by a factor of about 35. During the first preoptimization phase, a rough approximation of the optimal parameter set is computed based on performance bounds. Two application examples show the benefits of the proposed technique.     

基于Linux系统分析计算机C语言编程技巧

C语言程序设计是高效计算机专业学生必修的一门基础课程,同时也是后续课程的入门课程,对于掌握基本计算机技术有着重要意义。尤其在Linux系统下,该系统在所有操作系统中占着重要地位,如何掌握计算机C语言编程技巧是当务之急。为此,本文重点探讨基于Linux系统分析计算机C语言编程技巧。