Study of Object Oriented Petri Net and Its Application in Flexible Manufacturing Cells

This paper presents an object oriented Petri net (OOPN) schema to model the dynamic behaviors of a flexible manufacturing cells (FMCs). The OOPN paradigm incorporates the characteristics of a Petri net and OOP. It increases the maintainability and reusability of objects in Petri net modeling, thus it has more powerful modeling and analysis abilities.

Device design principles and bioelectronic applications for flexible organic electrochemical transistors

Organic electrochemical transistors(OECTs) exhibit significant potential for applications in healthcare and human-machine interfaces, due to their tunable synthesis, facile deposition, and excellent biocompatibility. Expanding OECTs to the fexible devices will significantly facilitate stable contact with the skin and enable more possible bioelectronic applications. In this work,we summarize the device physics of fexible OECTs, aiming to offer a foundational understanding and guidelines for material selection and device architecture. Particular attention is paid to the advanced manufacturing approaches, including photolithography and printing techniques, which establish a robust foundation for the commercialization and large-scale fabrication. And abundantly demonstrated examples ranging from biosensors, artificial synapses/neurons, to bioinspired nervous systems are summarized to highlight the considerable prospects of smart healthcare. In the end, the challenges and opportunities are proposed for fexible OECTs. The purpose of this review is not only to elaborate on the basic design principles of fexible OECTs, but also to act as a roadmap for further exploration of wearable OECTs in advanced bio-applications.

Intelligent Examination Monitoring and Maintenance for the Safety of Operation of Flexible Manufacturing Systems

Based on the system of electric power supply for flexible manufacturing systems (FMS), a study has been carried out on the intelligent safety examination, monitoring and maintenance of its running environment. On the basis of the specific feature of the power supply network of an FMS, real time monitoring system of the power supply network and the fault diagnostic expert system for the power equipment have been designed. This system can diagnose not only definite fault phenomena, but also fuzzy, uncertain fault phenomena as well. Fault diagnostic knowledge base for the power equipment has been founded hierarchy architecture model and the method of fault tree analysis. Feasibility of this system has been proved by computer simulation.

Petri net based modeling and analysis for weldingflexible manufacturing cell

Due to the development of advanced manufacturing technology and the introduction of Smart Manufacturing notion in the field of modern industrial production, welding flexible manufacturing using robot technology has become the inevitable developing direction on welding automation. Based on a new intelligent arc welding flexible manufacturing cell (WFMC), its system structure and control policies are studied in this paper. Aiming at the different information flows among every subsystem and central monitoring computer in this WFMC, Petri net theory is introduced into the process of welding manufacturing. A discrete control model of WFMC has been constructed, in which the system's status is regarded as place and the control process is regarded as transition. Moreover, grounded on automation Petri net principle, the judging and utilizing of information obtained from welding sensors are imported into Petri net structure, which extends the traditional Petri net concepts. The control model and policies researched in this paper have established foundation for further intelligent real time control on welding flexible manufacturing cell and system.

A Beam Search-based Algorithm for Flexible Manufacturing System Scheduling

A new algorithm is proposed for the flexible manufacturing system (FMS) scheduling problem in this paper. The proposed algorithm is a heuristic based on filtered beam search. It considers the machines and automated guided vehicle (AGV) as the primary resources. It utilizes system constraints and related manufacturing and processing information to generate machines and AGV schedules. The generated schedules can be an entire scheduling horizon as well as various lengths of scheduling periods. The proposed algorithm is also compared with other well-known dispatching rules-based FMS scheduling. The results indicate that the beam search algorithm is a simple, valid and promising algorithm that deserves further research in FMS scheduling field.

Simultaneous scheduling of machines and automated guided vehicles in flexible manufacturing systems using genetic algorithms

The problem of simultaneous scheduling of machines and vehicles in flexible manufacturing system (FMS) was addressed.A spreadsheet based genetic algorithm (GA) approach was presented to solve the problem.A domain independent general purpose GA was used,which was an add-in to the spreadsheet software.An adaptation of the propritary GA software was demonstrated to the problem of minimizing the total completion time or makespan for simultaneous scheduling of machines and vehicles in flexible manufacturing systems.Computational results are presented for a benchmark with 82 test problems,which have been constructed by other researchers.The achieved results are comparable to the previous approaches.The proposed approach can be also applied to other problems or objective functions without changing the GA routine or the spreadsheet model.

Component-based Control Software Design for Flexible Manufacturing System

A new method that designs and implements the component-based distributed & hierarchical flexible manufacturing control software is described with a component concept in this paper. The proposed method takes aim at improving the flexibility and reliability of the control system. On the basis of describing the concepts of component-based software and the distributed object technology, the architecture of the component-based software of the control system is suggested with the Common Object Request Broker Architecture (CORBA). And then, we propose a design method for component-based distributed & hierarchical flexible manufacturing control system. Finally, to verify the software design method, a prototype flexible manufacturing control system software has been implemented in Orbix 2.3c, VC + + 6. 0 and has been tested in connection with the physical flexible manufacturing shop at the WuXi Professional Institute.

MULTI-AGENT APPROACH FOR DISTRIBUTED FLEXIBLE MANUFACTURING SYSTEMS

This paper presents a multi agent model for the realization of the tasks dispatched in a distributed flexible manufacturing system.Agent behavior is described in terms of its capabilities and related environment.According to task execution forms,two kinds of task allocation methods are used and the proper communication mechanisms and negotiation mechanisms are involved to guarantee a high performance and high reliability for a DFMS.

Research on Flexible Flow⁃Shop Scheduling Problem with Lot Streaming in IOT⁃Based Manufacturing Environment

It is urgent to effectively improve the production efficiency in the running process of manufacturing systems through a new generation of information technology.According to the current growing trend of the internet of things(IOT)in the manufacturing industry,aiming at the capacitor manufacturing plant,a multi-level architecture oriented to IOT-based manufacturing environment is established for a flexible flow-shop scheduling system.Next,according to multi-source manufacturing information driven in the manufacturing execution process,a scheduling optimization model based on the lot-streaming strategy is proposed under the framework.An improved distribution estimation algorithm is developed to obtain the optimal solution of the problem by balancing local search and global search.Finally,experiments are carried out and the results verify the feasibility and effectiveness of the proposed approach.

Deadlock prevention for flexible manufacturing system

Deadlock must be prevented via the shop controller during the flexible manufacturing system （FMS） performing. Various models have been tried for the analysis and design of shop controller. Petri net is suitable to describe the dynamic behavior of the discrete event system, such as concurrency, conflict and deadlock, however, the verification of the .system behavior needs structure analysis with complex theoretical proof method. Temporal logic model checking has important advantages over traditional theorem prover. It is flatly automatic and can produce possible counter-example which is particularly important in finding subtle error in complex transition systems. In this paper, a new method for the deadlock prevention based on Petri net and Temporal Logic model checking is presented. The specification in the Temporal Logic is expressed according to some result of structure analysis of the Petri net. The model checking is employed to execute the formal verification, which will conduct an exhaustive exploration of all possible behaviors. Finally, an example is presented to demonstrate how the method works.

Flexible Developing System for Modern Instrument Manufacturing

The modern instrument manufacturing has many features, such as high technologies, multiple varieties and small quantities. Aiming at those features, an instrumentation flexible developing system （IFDS） is presented. It constitutes a kind of opening, compatible, extensible and upgradeable flexible developing system, and it will offer a kind of technology equipment for the research and development of new modern instrument products. Its flexible mechanism is able to be suited for different and special requirements of many instrument systems, and its system integrated mechanism is able to adapt to common technological features of most instrument systems. It is IFDS that makes it easy to accomplish a quick system integration of instrument products. IFDS solves key technological problems related to modern instruments development, develops multiple systems for modern instrument development and accomplishes rapid development of series of new products.

Development of a Simulation-Based Intelligent Decision Support System for the Adaptive Real-Time Control of Flexible Manufacturing Systems

This paper describes a simulation-based intelligent decision support system (IDSS) for real time control of a flexible manufacturing system (FMS) with machine and tool flexibility. The manufacturing processes involved in FMS are complicated since each operation may be done by several machining centers. The system design approach is built around the theory of dynamic supervisory control based on a rule-based expert system. The paper considers flexibility in operation assignment and scheduling of multi-purpose machining centers which have different tools with their own efficiency. The architecture of the proposed controller consists of a simulator module coordinated with an IDSS via a real time event handler for implementing inter-process synchronization. The controller’s performance is validated by benchmark test problem.

Manufacturing Communication: DCOM-MMS-based Approach for Flexible Manufacturing System

A design approach of manufacturing communication is presented for flexible manufacturing system in this paper. The primary objective aims at making the flexible manufacturing control system provided with interoperability and reconfigurability. Based on describing manufacturing message specification (MMS) and distributed component object model (DCOM), a client/server manufacturing communication model is built with MMS standard and DCOM middleware, and the communication interfaces between MMS client and MMS server are designed with Microsoft interface definition language (MIDL) and abstract syntax notation one (ASN.1) of MMS services. As a result, DCOM and MMS integration leads to such client/ server communication capabilities independent of different operating systems and manufacturing devices in flexible manufacturing automation environment. Finally, to verify the new design approach, a prototype system of robot control system has been implemented in MS 2000 Server/Professional Operating System and VC++ 6.0 Developer Environments.

A Critical Review of Machine Loading Problem in Flexible Manufacturing System

Production planning is the foremost task for manufacturing firms to deal with, especially adopting Flexible Manufacturing System (FMS) as the manufacturing strategy for production seeking an optimal balance between productivity-flexibility requirements. Production planning in FMS provides a solution to problems regarding part type selection: machine grouping, production ratio, resource allocation and loading problem. These problems need to be solved optimally for maximum utilization of resources. Optimal solution to these problems has been a focus of attention in production and manufacturing, industrial and academic research since a number of decades. Evolution of new optimization techniques, software, technology, machines and computer languages provides the scope of a better optimal solution to the existing problems. Thus there remains a need of research to solve the problem with latest tools and techniques for higher optimal use of available resources. As an objective, the researchers need to reduce the computational time and cost, complexity of the problem, solution approach viz. general or customized, better user friendly communication with machine, higher freedom to select the desired objective(s) type(s) for optimal solution to the problem. As an approach to the solution to the problem, a researcher first needs to go for an exhaustive literature review, where the researcher needs to find the research gaps, compare and analyze the tools and techniques used, number of objectives considered for optimization and need, and scope of research for the research problem. The present study is a review paper analyzing the research gaps, approach and techniques used, scope of new optimization techniques or any other research, objectives considered and validation approaches for loading problems of production planning in FMS.

Design and Implementation of Distributed Numerical Control in Flexible Manufacturing System

To monitor, control and manage the work process of computer numerical control machine tools in a flexible manufacturing system (FMS) effectively, the distributed numerical coutrol (distributed-NC) software should be innovated with the characteristics of modularization and reconfiguration. In this paper, firstly, distributed-NC functions in the FMS environment are described. Then, we present a design and development method of the real time distributed-NC that is on the basis of the re-coufigurable software and hardware platform and with an object-oriented model concept. Finally, to verify the proposed method, the distributed-NC software has been implemented in VC++ 6.0 and has been tested in connection with the different physical flexible manufacturing shops.

Research on Flexible Manufacturing System in Mechatronics Professional Comprehensive Training

According to the characteristics of flexible manufacturing systems, the article describes the equipment components and hardware architecture of flexible manufacturing systems in school. Taking welding assemble process as an example to elaborate production process automation, the paper put forward a flexible manufacaxring system combined with laboratory equipment and various grades, professional knowledge and teaching characteristics and differentiated teaching programs, the creation of the laboratory project was planned and implemented to specific engineering training programs, so that students has been expanded in the depth of expertise and breadth, experimental skills and innovation capacity has been improved, the teaching effect has also been significantly improved..

Study on Robot Sequencing Model in Flexible Manufacturing System Using Timed Petri Net

In a flexible manufacturing system, both the productivity and the flexibility of the manufacturing processes are highly influenced by robot sequencing. In this paper a petri net based approach for sequencing of industrial robot in a flexible manufacturing cell is presented and a decision structure for robot sequencing based on different criteria is described.

Recent advances in nanofiber-based flexible transparent electrodes

Flexible and stretchable transparent electrodes are widely used in smart display,energy,wearable devices and other fields.Due to the limitations of flexibility and stretchability of indium tin oxide electrodes,alternative electrodes have appeared,such as metal films,metal nanowires,and conductive meshes.However,few of the above electrodes can simultaneously have excellent flexibility,stretchability,and optoelectronic properties.Nanofiber(NF),a continuous ultra-long one-dimensional conductive material,is considered to be one of the ideal materials for high-performance transparent electrodes with excellent properties due to its unique structure.This paper summarizes the important research progress of NF flexible transparent electrodes(FTEs)in recent years from the aspects of NF electrode materials,preparation technology and application.First,the unique advantages and limitations of various NF materials are systematically discussed.Then,we summarize the preparation technology of various advanced NF FTEs,and point out the future development trend.We also discuss the application of NFs in solar cells,supercapacitors,electric heating equipments,sensors,etc,and analyze its development potential in flexible electronic equipment,as well as problems that need to be solved.Finally,the challenges and future development trends are proposed in the wide application of NF FTEs in the field of flexible optoelectronics.

Direct fabrication of flexible tensile sensors enabled by polariton energy transfer based on graphene nanosheet films

A fundamental problem in the direct manufacturing of flexible devices is the low melting temperature of flexible substrates,which hinders the development of flexible electronics.Proposed here is an electron-cyclotron-resonance sputtering system that can batch-fabricate devices directly on flexible substrates under a low temperature by virtue of the polariton energy transfer between the plasma and the material.Flexible graphene nanosheet-embedded carbon(F-GNEC)films are manufactured directly on polyimide,polyethylene terephthalate,and polydimethylsiloxane,and how the substrate bias(electron energy),microwave power(plasma flux and energy),and magnetic field(electron flux)affect the nanostructure of the F-GNEC films is investigated,indicating that electron energy and flux contribute to the formation of standing graphene nanosheets in the film.The films have good uniformity of distribution in a large size(17 mm×17 mm),and tensile and angle sensors with a high gauge factor(0.92)and fast response(50 ms)for a machine hand are obtained by virtue of the unique nanostructure of the F-GNEC film.This work sheds light on the quantum manufacturing of carbon sensors and its applications for intelligent machine hands and virtual-reality technology.

Flexible ERP:Enterprise Information System Under the Agile Manufacture Mode

Flexibility is the demand of management revolution,and also the milestone of management development.The flexible ERP system is the information system to orientate variety and handle uncertainties.The market with rapid change and agile manufacture need a flexible ERP system.The article elaborates the meanings and characteristics about flexibility,the flexibility of ERP and the flexible ERP system;it discussed the necessity,the possibility and the related condition of setting up the flexible ERP system;and puts forward the strategy and the approaches of setting up the flexible ERP system.