A HOLONIC FRAMEWORK OF RECONFIGURABLE SHOP FLOOR CONTROL SYSTEMS IN AUTOMATED MANUFACTURING SYSTEMS

The agility and the flexibility of the current shop floor control systems have been limited so far, owing to the lack of structural flexibility and agility in its control software layer. Most of them are based on traditional hierarchical architecture and the top down approach and depend structurally on their specific configuration and job scheduling. Not only can they hardly satisfactorily adapt to these increasing changes and disturbances, but also make the redevelopment and maintenance of shop floor control system (SFCS) to need high cost and much time. And SFCS based on the heterarchical architecture don′t provide a predictable and high performance system, especially not in the heterogeneous environments, where the resources are scarce and the current decisions have serious repercussions on the future performances. For this reason, the heterarchical control is hardly applied in industry. Obviously, it is necessary to develop a new structural framework of reconfigurable SFCS to improve their agility, flexibility and maintainability. This paper presents a holonic framework of reconfigurable SFCS based on holonic manufacturing concepts. The framework is composed of resource holons, product holons and other staff holons. The model of each holon and the co operative mechanisms of holons are described. To verify the proposed approach experimentally, a prototype reconfigurable SFCS for a flexible manufacturing shop floor producing discrete parts is implemented.

A Methodology for Developing Maintenance Policy for Automated Manufacturing Plants

An effort has been made in this paper to describe unique aspect of AMP's. Effects of unique aspects on maintenance management of AMP's are shown. In the absence of well validated and universally accepted models for managing AMP's maintenance, a step by step approach has been suggested.

The RFID-Based Manufacturing and Inventory Revolution

Radio frequency identification (RFID) is a contactless form of automatic identification and data capture (AIDC) technology. This paper explores the use of RFID in the new field of manufacturing automation and quality control. This paper consists of five parts. The first part gives a brief background and introduction of technology. The proposed use of RFID technology in the field of manufacturing automation and quality control is discussed in second part. The third part covers its use in the field of warehouse management system. Part four is a local review and analysis of RFID technology in manufacturing and warehousing which would support the potential use of this technology locally at China. The last part of paper gives concluding remarks about the RFID technology with recommendations of RFID use in these areas.

Sensor Networking: Concepts, Applications, and Challenges

Sensor network has experienced world-wide explosive interests in recent years. It combines the technology of modern microelectronic sensors, embedded computational processing systems, and modern computer and wireless networking methodologies. In this overview paper, we first provide some rationales for the growth of sensor networking. Then we discuss various basic concepts and hardware issues. Four basic application cases in the US. National Science Foundation funded Ceneter for Embedded Networked Sensing program at UCLA are presented. Finally, six challenging issues in sensor networks are discussed. Numerous references including relevant papers, books, and conferences that have appeared in recent years are given.

Computation of an Emptiable Minimal Siphon in a Subclass of Petri Nets Using Mixed-Integer Programming

Deadlock resolution strategies based on siphon control are widely investigated.Their computational efficiency largely depends on siphon computation.Mixed-integer programming(MIP)can be utilized for the computation of an emptiable siphon in a Petri net(PN).Based on it,deadlock resolution strategies can be designed without requiring complete siphon enumeration that has exponential complexity.Due to this reason,various MIP methods are proposed for various subclasses of PNs.This work proposes an innovative MIP method to compute an emptiable minimal siphon(EMS)for a subclass of PNs named S^(4)PR.In particular,many particular structural characteristics of EMS in S4 PR are formalized as constraints,which greatly reduces the solution space.Experimental results show that the proposed MIP method has higher computational efficiency.Furthermore,the proposed method allows one to determine the liveness of an ordinary S^(4)PR.

Cycle Time Analysis for Wafer Revisiting Process in Scheduling of Single-arm Cluster Tools

Some wafer fabrication processes performed by cluster tools require revisiting. With wafer revisiting, a cluster tool is very difficult to be scheduled due to a large number of possible schedules for the revisiting process. Atomic layer deposition （ALD） is a typical process with wafer revisiting that should be performed by cluster tools. This paper discusses the scheduling problem of single-arm cluster tools for the ALD process. In scheduling such a system, the most difficult part is to schedule the revisiting process such that the cycle time is minimized. Thus, this paper studies the revisiting process of ALD with revisiting times k = 3, 4, and 5, and analytical expressions are obtained to calculate the cycle time for the k possible schedules. Then, the schedule with the minimal cycle time is the optimal one. In this way, the scheduling problem of such a revisiting process becomes very simple and this is a significant improvement in scheduling cluster tools with wafer revisiting. Illustrative example is presented to show the application of the proposed method.

Measurement and Compensation of Deviations of Real Tooth Surface of Spiral Bevel Gear

This paper presents a method for measurement of deviation of the real gear tooth surface from the theoretical one with a coordinate measurement machine and compensation of repeatable parts. By investigation of characteristics of distortion of the gear tooth surface along the circle direction, the deviation is derived from distortion, and the definition of deviation with the geometrical invariability is proposed. Then the approach for determination of the location and orientation of the gear with respect to the coordinate measurement machine and the measurement way are developed. The deviation is represented with a difference surface, and an algorithm for derivation of parameters of global form deviations from the discrete points has been provided. Finally, the compensation approach is discussed.

Anti⁃icing/De⁃icing Mechanism and Application Progress of Bio⁃inspired Surface for Aircraft

Icing on the surface of aircraft will not only aggravate its quality and affect flight control,but even cause safety accidents,which is one of the important factors restricting all-weather flight.Bio-inspired anti-icing surfaces have gained great attention recently due to their low-hysteresis,non-stick properties,slow nucleation rate and low ice adhesion strength.These bio-inspired anti-icing surfaces,such as superhydrophobic surfaces,slippery liquid-infused porous surfaces and quasi-liquid film surfaces,have realized excellent anti-icing performance at various stages of icing.However,for harsh environment,there are still many problems and challenges.From the perspective of bioinspiration,the mechanism of icing nucleation,liquid bounce and ice adhesion has been reviewed together with the application progress and bottleneck issues about anti-icing in view of the process of icing.Subsequently,the reliability and development prospect of active,passive and active-passive integrated anti-icing technology are discussed,respectively.

The Realization of Mass Customization Using Modularization Method

In the view of the comparison of Mass Customization ( MC) with Mass Production and Customization Production, the objectives of MC are analyzed. It is pointed out that the core objectives of MC are to realize in dividuation customization, low cost, quick response to market demands. The modul arization theory is simply introduced. Based on the characteristics of modular ization, the mechanism of realizing MC with modularization is analyzed. The in dividuation customization can be realized with the different combinations of mod ules. The low cost can be realized with the scale economy and the category econo my of modules. The quick response can be realized with standard modules and its interfaces. So, the modularization is a kind of effective method in realizing MC . The modularization for MC is a systems engineering. With product modularized, production organization and management and manufacturing equipment will be chang ed. In addition, the paper also proposes a Mass Customization production model w hich is based on modularization. This Mass Customization production model is con sisted of modularization of product design, specialization of manufacturing, Vir tual Enterprises based on modularizing enterprises, and modularizing manufacturi ng equipment. The module design for MC, modularizing enterprises, and reconfigur able automation manufacturing equipment are discussed, and it is pointed out tha t they are the important supports for MC.

A differentiated approach for justification of advanced manufacturing technologies

European companies rely on advanced manu- facturing technologies （AMTs） in order to succeed in an environment of high labour costs, increasing competition and rising customer expectations. AMT implementation is often a high-risk investment. Many companies experience a misalignment between the installed functionality and pro- duction needs. There is a need for decision support in order to take into account all possible advantages and disad- vantages of the technology implementation, and ensure that the technology meets the requirements of the production processes. In this article, a differentiated technology justi- fication approach is introduced. The approach suggests a combination of strategic, financial and risk justification methods. The recommended number and type of methods depend on the integration level of the technical system under consideration, ranging from stand-alone machines to large and integrated production systems. The approach was developed based on a literature review and a case study. The application of the approach was presented in a case where several types of pipe bending technology were evaluated.