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Manufacturing Systems (manufacturing + systems)
Kinds of Manufacturing Systems Selected AbstractsDEADLOCK AVOIDANCE FOR FLEXIBLE MANUFACTURING SYSTEMS WITH CHOICES BASED ON DIGRAPH CIRCUIT ANALYSISASIAN JOURNAL OF CONTROL, Issue 2 2007Wenle Zhang ABSTRACT Due to existence of concurrent part flows and resource sharing in modern automated flexible manufacturing systems (FMS), deadlock is a common problem and its occurrence causes loss of productivity. When a manufacturing system is modeled by a digraph, existence of circuits in such a graph is a necessary condition for deadlock. Our previous work further showed that the knot and order of a circuit is closely related to impending deadlocks , a type of deadlock that is more difficult to detect. In this paper, we extend our previous work on deadlock avoidance for flexible manufacturing systems to allow choices in process flows (a.k.a., flexible part routing). Due to introduction of choices, part flow dynamics become more sophisticated and our previous results are no longer valid. A systematic circuit analysis is performed in this paper. New concepts such as broken circuit, basic circuit, choice circuit and supremal circuit are introduced to reduce significantly the number of circuits thus improving efficiency of our approach. The extended method is highly permissive with the adjusted effective free space calculation to capture more necessary parts flow dynamics, especially when multiple knots exist in the digraph model. The online policy runs in polynomial time once the set of basic circuits of the digraph is computed offline. Simulation results on selected examples are given. [source] The concept of work compatibility: An integrated design criterion for improving workplace human performance in manufacturing systemsHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 4 2004S. Abdallah In this paper, we present the concept of work compatibility as an integrated work design criterion that simultaneously improves human health and safety, productivity, and work quality in manufacturing systems. In this respect, we have modeled work compatibility as a work design parameter that mathematically integrates the energizing (i.e., system resources) and the demand (i.e., system requirements) forces in the work system. A mathematical equation has been derived for the work compatibility matrix. Furthermore, an operating zone has been developed in which there is a region of optimality for the employee to function on practical grounds with a good degree of efficiency and sustainability. An application example is provided to demonstrate the potential of work compatibility to improve productivity and quality along with improvement in worker safety and health. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 379,402, 2004. [source] System design in normative and actual practice: A comparative study of cognitive task allocation in advanced manufacturing systemsHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 2 2004Sotiris Papantonopoulos The Human Factors Engineering approach to human-machine system design is based largely on normative design methods. This article suggests that the scope of Human Factors Engineering shall be extended to the descriptive study of system design in actual practice by the application of theoretical frameworks that emphasize the role of the system-design practitioner and organization in the design process. A comparative study of system design in normative and actual practice was conducted in the design of cognitive task allocation in a Flexible Manufacturing System (FMS) cell. The study showed that the designers' allocation decisions were influenced strongly by factors related to their own design practices, yet exogenous to the tasks to be allocated. Theoretical frameworks from Design Research were applied to illustrate differences between normative and actual practice of system design. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 181,196, 2004. [source] A comparative simulation study of work processes in autonomous production cellsHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 1 2002Christopher Schlick An approach to human-centered design and assessment of work processes in flexible manufacturing systems with the help of dynamic task networks is presented. To model and simulate the task networks, the method of timed colored Petri Nets is used. Two task networks are developed. The first task network is a model of work processes in Autonomous Production Cells (APCs). The second task network represents work processes in conventional Computer Numerically Controlled (CNC)-based manufacturing systems. The material processing technology is associated with 5-axis milling. The values of attributes of task elements were acquired empirically on a fine-grained level with reference to a sample milling order. Comparative hypotheses regarding time-on-task, supervisory control functions, levels of cognitive control, human error (HE), and labor division were then formulated. To test these hypotheses, several simulation experiments were conducted. The results from inferential statistics show that single-operator APCs have a 30% higher efficiency in relation to total time-on-task. Moreover, the level of cognitive control is significantly shifted toward rule- and knowledge-based behavior. Surprisingly, the simulation of minor HE does not demonstrate a significantly worse performance from APCs. A simulated labor division among central process planner and production operator allows an additional efficiency improvement of approximately 15%. However, the labor division has two important drawbacks: first, a sequential incompleteness of operators' task spectrum occurs; second, the operator has to cope with hierarchical task incompleteness. Finally, a sensitivity analysis was carried out to investigate the effects of varying lot sizes and number of processed orders. © 2002 John Wiley & Sons, Inc. [source] A conceptual framework for agent-based agile manufacturing cellsINFORMATION SYSTEMS JOURNAL, Issue 2 2004Jianming Yu Abstract., Agile manufacturing techniques are perceived as the manufacturing systems of the future. Agile manufacturing cells are dynamic and reconfigurable and the modelling of the manufacturing cells and its interaction mechanism is critical to its successful use. This paper deals with the architecture and cooperation mechanism of web-based agile manufacturing cells. Based on an analysis of structure and organization requirements of agile manufacturing cells and a comparison of three basic architectures of manufacturing systems, the quasi-heterarchical architecture is used for the agile manufacturing cell. Functional layers are defined in this architecture to make the cell's control system reconfigurable and reusable. Agent technology is adopted for implementation of each layer's functions to establish an agent-based model of agile manufacturing cells. Four types of agents including cooperation agent, job management agent, resource broker agent, and resource control agent are defined, and their functions discussed. Finally, a real time interaction mechanism of the agents is presented by considering the activities during the agents' cooperation in an agile manufacturing cell. [source] Two-dimensional occluded object matching using petri netsINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 3 2002Chuan Zhou This article discusses the use of Petri nets to model the process of object matching between an image and a model under different two-dimensional geometric transformations. This transformation finds its applications in sensor-based robot control, flexible manufacturing systems, industrial inspection, and so on. Its topological structure relation, called point-line relation structure (PLRS), presents a Petri net-based description approach for object structure. It has been shown how Petri nets can be used to model the matching process, and an optimal or near optimal matching can be obtained by tracking the reachability graph of the net. The experiment result shows that objects can be successfully identified and located under two-dimensional transformation such as translations, rotations, scale changes, and distortions due to partial object occlusion. © 2002 Wiley Periodicals, Inc. [source] Sequencing material handling equipment in production facilitiesINTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 4 2007Manolis N. Kritikos Abstract In this article we consider the problem of sequencing material handling equipment in manufacturing systems, subject to constraints that restrict the start and end time of each production activity, according to pre-specified daily resource operational schedules and process planning information. The underlying decision problem is modeled using an integer programming formulation similar to vehicle routing with time windows (VRPTW). To take advantage of standard approaches for the VRPTW, we develop a transformation schema that allows a one-to-one mapping between the manufacturing problem and VRPTW. An efficient heuristic to solve the resulting transformed problem is proposed. The method, which is a penalty-based sequential insertion heuristic, allows routes to be constructed by exploiting the tradeoff between material handling and resource starvation costs. The steps of the method are illustrated via a comprehensive example and results on benchmark problems are reported. [source] Material handling device selection in cellular manufacturingJOURNAL OF MULTI CRITERIA DECISION ANALYSIS, Issue 6 2001Marcello Braglia Abstract This paper presents a new multi-criteria decision model for the material handling device (MHD) selection problem in cellular manufacturing systems. Given a set of manufacturing cells based on several automatic work-centres, the technique makes it possible to select a particular MHD for each cell in an integrated way, with different constraints being taken into consideration. The approach is based on two different multi-attribute analyses executed with analytic hierarchy process (AHP) methodology, and a final integer linear programming including important limitations faced by the designer when making MHD investment decisions. An example using real data is provided to illustrate this methodology. Copyright © 2002 John Wiley & Sons, Ltd. [source] An application of robust control technique to manufacturing systems with uncertain processing timeOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 6 2000E. K. Boukas Abstract This paper studies the inventory control problem for a production system with uncertain processing time and delay in control. First, the stabilization of the delayed system is analysed. Then, a controller is designed such that a disturbance attenuation of the system is achieved. The problem of robust control of the system with parametric uncertainty is also investigated. Linear matrix inequality approach is employed to solve the above problems. A numerical example is given to show the potential of the proposed techniques. Copyright © 2000 John Wiley & Sons, Ltd. [source] Introduction of flexible packaging systems for toiletry productsPACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2001Yuji Ikeda Abstract Flexible manufacturing systems (FMS) are rapidly gaining in importance for manufacturers throughout the industrialized world. Lion Corporation is no exception in its need of FMS because of the great variety of toiletry and household products it produces. Toiletry products, such as toothpaste, detergent and shampoo, are our mainstay products, which account for 75% of our total sales. On our production lines, therefore, it is essential that they can be changed flexibly for the manufacture of ever-changing products. Introduced in this report are some of our flexible packaging systems, which use carriers, robots, standardized shampoo bottles, etc., without relying on special tools or new parts for line change. Innovation of our flexible packaging systems for greater flexibility and cost reduction will continue in the future. Copyright © 2001 John Wiley & Sons, Ltd. [source] A Cumulative Sum scheme for monitoring frequency and size of an eventQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 6 2010Zhang Wu Abstract This article proposes a Cumulative Sum (CUSUM) scheme, called the TC-CUSUM scheme, for monitoring a negative or hazardous event. This scheme is developed using a two-dimensional Markov model. It is able to check both the time interval (T) between occurrences of the event and the size (C) of each occurrence. For example, a traffic accident may be defined as an event, and the number of injured victims in each case is the event size. Our studies show that the TC-CUSUM scheme is several times more effective than many existing charts for event monitoring, so that cost or loss incurred by an event can be reduced by using this scheme. Moreover, the TC-CUSUM scheme performs more uniformly than other charts for detecting both T shift and C shift, as well as the joint shift in T and C. The improvement in the performance is achieved because of the use of the CUSUM feature and the simultaneous monitoring of T and C. The TC-CUSUM scheme can be applied in manufacturing systems, and especially in non-manufacturing sectors (e.g. supply chain management, health-care industry, disaster management, and security control). Copyright © 2009 John Wiley & Sons, Ltd. [source] Process vs resource-oriented Petri net modeling of automated manufacturing systems,ASIAN JOURNAL OF CONTROL, Issue 3 2010NaiQi Wu Abstract Since the 1980s, Petri nets (PN) have been widely used to model automated manufacturing systems (AMS) for analysis, performance evaluation, simulation, and control. They are mostly based on process-oriented modeling methods and thus termed as process-oriented PN (POPN) in this paper. The recent study of deadlock avoidance problems in AMS led to another type of PN called resource-oriented PN (ROPN). This paper, for the first time, compares these two modeling methods and resultant models in terms of modeling power, model complexity for analysis and control, and some critical properties. POPN models the part production processes straightforwardly, while ROPN is more compact and effective for deadlock resolution. The relations between these two models are investigated. Several examples are used to illustrate them. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Non-blocking decentralized control of discrete event systems based on Petri nets,ASIAN JOURNAL OF CONTROL, Issue 3 2010Feihua Lu Abstract The non-blocking property of discrete event systems can formulate many practical and important properties of manufacturing systems, such as deadlock freeness, liveness and reversibility. But it is difficult to guarantee non-blocking control. This paper presents a hybrid approach to decentralized control of discrete event systems. More generalized constraints are considered in this approach, which gives a graphical way of designing coordinators to keep the non-blocking property of the closed-loop system with decentralized supervisors. This approach also guarantees that the closed-loop system is maximally permissive. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] An optimal maintenance policy based on generalized stochastic Petri nets and periodic inspectionASIAN JOURNAL OF CONTROL, Issue 3 2010Ching-Kao Chang Abstract Periodic maintenance of equipment is essential for its optimum performance, thereby enabling production efficiency. In the past, studies on preventive maintenance of automated manufacturing systems (AMS) determined the optimal preventive maintenance policy under different performance indexes. Generally, most hypotheses indicate that equipment reliability can be restored to 1.0 through preventive and corrective maintenance. However, in practical application, the implementation of preventive maintenance results in partial deterioration of equipment; moreover, the reliability of equipment cannot be restored to as-good-as-new. In addition, the greater the complexity of connections of the equipment, the greater is the difficulty in determining the timing for preventive maintenance. On account of these characteristics, generalized stochastic Petri nets (GSPN) are well-suited for the implementation of preventive maintenance. Therefore, this paper applies GSPN for deciding the optimal maintenance policy and constructing models for different levels of maintenance and renewal for an AMS with a serial-parallel layout. As a result of the application of GSPN, the following optimal maintenance policy for an AMS was obtained in this study: Preventive maintenance conducted at intervals of every 240 hours will reduce cost by 46% as opposed to the practice of replacing defective parts when necessary. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] DEADLOCK AVOIDANCE FOR FLEXIBLE MANUFACTURING SYSTEMS WITH CHOICES BASED ON DIGRAPH CIRCUIT ANALYSISASIAN JOURNAL OF CONTROL, Issue 2 2007Wenle Zhang ABSTRACT Due to existence of concurrent part flows and resource sharing in modern automated flexible manufacturing systems (FMS), deadlock is a common problem and its occurrence causes loss of productivity. When a manufacturing system is modeled by a digraph, existence of circuits in such a graph is a necessary condition for deadlock. Our previous work further showed that the knot and order of a circuit is closely related to impending deadlocks , a type of deadlock that is more difficult to detect. In this paper, we extend our previous work on deadlock avoidance for flexible manufacturing systems to allow choices in process flows (a.k.a., flexible part routing). Due to introduction of choices, part flow dynamics become more sophisticated and our previous results are no longer valid. A systematic circuit analysis is performed in this paper. New concepts such as broken circuit, basic circuit, choice circuit and supremal circuit are introduced to reduce significantly the number of circuits thus improving efficiency of our approach. The extended method is highly permissive with the adjusted effective free space calculation to capture more necessary parts flow dynamics, especially when multiple knots exist in the digraph model. The online policy runs in polynomial time once the set of basic circuits of the digraph is computed offline. Simulation results on selected examples are given. [source] Changing economies of scale , synergies between implementation of an ecological tax reform and development of industrial ecosystemsBUSINESS STRATEGY AND THE ENVIRONMENT, Issue 6 2001Christoph Bey In this paper an investigation is presented into the long-term effects of an ecological tax reform. Exploring time frames of different length, the paper considers the reform's effects on manufacturing systems, especially on economies of scale. Industrial ecology, a framework for restructuring into industrial ecosystems, is one attempt at transforming the socio-economic system for sustainability. The paper points out the synergetic effects an ecological tax reform has with those restructuring efforts for sustainable industry and society. For that purpose, the economies of scale in the current linear production system and those found in the closed-loop circular structures of industrial ecosystems are compared, and the paper is concluded by a discussion of opportunity costs of implementation of an ecological tax reform and industrial ecological restructuring. Copyright © 2001 John Wiley & Sons, Ltd and ERP Environment [source] | ||||||||||||||||