A distributed architecture for automated manufacturing systems

The concept of distributed architectures for automated manufacturing systems is presented here. A modular architecture for a logical cell-controller is proposed where shopfloor level modules are incorporated in the cell control system so as to allow active co-operation for distributed decision making and control. Two examples illustrating distributed formulations for specific planning and control are presented. These examples demonstrate the feasibility and potential for distributed architectures for automated manufacturing. This work has been supported by a grant from the Institute of Manufacturing Research, Wayne State University, USA.     

基于CORBA-MMS的制造自动化通讯系统设计

为了有效地集成自动化制造车间中数控机床、机器人、自动导向小车等智能设备,进行控制实体与智能设备之间的合理通信设计是十分必要的。在描述制造报文规范(MMS)和CORBA分布式技术的基础上,提出了制造自动化通讯系统的设计方法。构建了基于CORBA-MMS的自动化制造控制系统通讯系统结构,并对建立在此通讯结构基础上的自动化制造控制系统中控制实体的通讯接口进行了设计。此设计方法在无锡职业学院的单元自动化控制系统中得到了验证。     

Computer-aided feature-based design for net shape manufacturing

Contemporary computer-based design tools are not suitable for concurrent engineering oriented product design due to (a) their particular and stand-alone functionality, (b) the lack of a capability to support interactive decision-making, and (c) the heavy involvement of designer expertise and experience. This paper presents a feature-based design for a manufacturing framework which is able to support the practice of concurrent engineering by providing functions designed specifically for net shape product design and on-line design guidance. Knowledge-based and object-oriented modeling technologies are employed to develop design evaluation facilities. An object-oriented product model, embedded with product design and process knowledge, is constructed and used for design evaluation. Geometric reasoning is performed on features, feature interactions, and overall shape to identify areas that may conflict with design principles. This paper concentrates on design for net shape manufacturing with an emphasis on die casting and injection molding processes. However, the proposed framework is general enough for other net shape processes by customizing process specific features and encoding process design rules.     

Technology for the control of quality in automated manufacturing

This paper reviews the present status of technology for the quality assurance of products produced by flexible automation parts-manufacturing. Two examples of practical systems that represent typical products (rotational and prismatic work-pieces) are described with particular emphasis on control functions relevant to product quality     

A hybrid approach of ordinal optimization and iterated local search for manufacturing cell formation

One of the fundamental problems in cellular manufacturing is grouping products with similar features into families and associated machines into cells. The objective is to maximize grouping efficacy, which indicates the within-cell machine utilization and the inter-cell movement. In this paper, a novel hybrid approach combining ordinal optimization (OO) and iterated local search (ILS) is presented to solve it in a short time. The hybrid algorithm takes ordinal optimization as the main framework, while ILS is embedded in the framework as a sub-procedure. In each iteration of the algorithm, according to OO strategy, r best solutions are accepted as the initial solutions for the embedded ILS in turn. From each initial solution, H solutions are generated and totally rH “good enough” solutions are obtained. For the ILS algorithm, a very-large scale neighborhood, cyclic transfer neighborhood is adopted, the characteristic of which is several products moving simultaneously in a cyclical manner. A reinforcement kick strategy is also proposed for the ILS algorithm, in which the products and machines are regrouped according to the current grouping relationships between products and machines. Computational experience on a set of group technology problems available in the literature shows the efficiency of the new hybrid algorithm. The results obtained by the hybrid algorithm are comparable to those obtained by other known algorithm in the literature for the problem.     

西门子S7-200PLC在冲床送料及加工中的应用

针对空调电动机端盖类零件,利用西门子S7-200PLC(CPU224)对多工位连续模冲床的送料机构及加工实现自动控制,提高了冲床送料及加工的自动化水平和可靠性.     

On an iterative deadlock prevention approach for automated manufacturing systems

In Hu (Transactions of the Institute of Measurement and Control 33:59–76, 2011), Petri nets are utilized to describe, analyse and control automated manufacturing systems (AMS). In order to suppress deadlock occurrences in AMS, a method to derive the bad markings iteratively using a mixed integer programming-based algorithm is proposed. To validate the effectiveness and efficiency of the proposed approach, two examples were demonstrated in Hu (Transactions of the Institute of Measurement and Control 33:59–76, 2011). This paper shows that the uncontrolled Petri net model in one of the examples is incorrect. It is also shown that the structural complexity of the computed monitors for both examples can be reduced with the same or more permissive system behaviours.     

A virtual testbed for the life-cycle design of automated manufacturing facilities

A large-scale automated manufacturing facility employs various types of automated machines and equipment including material handling and material processing systems. It typically involves extremely complicated operations to achieve the desired performance with less or no manual labour. Design of such a complete system requires a series of difficult design and implementation tasks. This paper describes a virtual testbed to support the life-cycle design of large-scale automated manufacturing facilities such as the postal mail process facility and gear manufacturing factory. The architecture of the virtual testbed is based on the extended real-time control system. The virtual environment provides the design engineer with a unique way of considering all functions of life-cycle system support in the process of facility design. Two examples are given to illustrate the effectiveness and extent of the virtual design system.     

自动制造系统中的迭代式死锁预防策略

为解决自动制造系统中的死锁问题,提出一种将混合整数规划算法和Petri网相结合的迭代式预防策略。在该策略中,混合整数规划算法中的0／1变量用来表示Petri网模型中的库所和变迁是否与一个最大的可被清空的信标相关。由于从一个最大的可被清空的信标中可以容易地计算出一个严格极小信标,就可以在不遍历所有的严格极小信标的情况下,直接求得一组基本信标,从而大大地降低了策略的时间算法复杂度。同时,控制该组基本信标可以确保目标系统具有简单的控制器结构和尽可能多的许可行为。实验结果表明了该控制策略的有效性和高效性。     

Object-oriented Petri nets for modelling and analysis of automated manufacturing systems

This paper presents an Object-oriented Petri Net (OPN) approach to model and analyse the dynamic behaviours of an Automated Manufacturing System (AMS). Both the basic and the complete OPN models are introduced to represent the generic and specific dynamic behaviours of an AMS, respectively. Based on the basic OPN model, we need to construct the Object Communication Net (OCNet) for each physical object, and then employ the theory of invariants to perform the deadlock analysis. For an analysed non-deadlock basic OPN model, the complete OPN model for a specific AMS may be effectively derived from it by only including those related system constraints (e.g. part routing, resource capacity), since the basic OPN class library is reusable. A conflict analysis approach is then introduced to identify all the conflicting events involved in the complete OPN model, so that the most suitable control/decision strategy for resolving each conflict event may be suggested. Consequently, a rule-based control software may be implemented directly from the specification of the validated complete OPN model by following a number of transformation rules.     

Vision-based automated inspection system in computer integrated manufacturing

The industrial application of an automated inspection system that aims to enhance the efficiency and flexibility of a computer integrated manufacturing system (CIMS) is proposed in this paper. A machine-vision-based approach is adopted to utilise its advantages of measurement flexibility, high resolution, and non-destruction. With a closed-loop feedback control architecture, the inspection procedures are fully integrated with the production process to detect and to recover abnormal operations in a real-time mode. Implementation of such a system at a physical shop floor for socket inspection is presented as an example.     

制造自动化中物流系统设计策略研究

在制造自动化系统（FMS、CIMS等）中,物流系统的设计必须满足整个制造系统的要求,设计策略直接影响物流系统,以至于整个制造系统的效果。本文从制造自动化对物流系统要求出发,提出了物流系统总体设计及各组成部分设计的策略,并分析了相关因素对物流系统设计的影响。     

An automated inspection system for stents

In this paper, the automated inspection of stent manufacturing is presented. It was developed and applied to acquire, process, and analyze the image data of stents using a line-scan camera and automated multi-axes scan mechanics to acquire the image data during the scanning process. A stent is a wire-metal-mesh tube used to prop open an artery during angioplasty. The stent is collapsed to a small diameter and put over a balloon catheter. It is then moved into the area of the blockage to restore normal blood flow and keep an artery open. A cardiovascular stent has hundreds of critical features with tight tolerances. They must be 100% inspected for dimensional conformity, and also for visual defects. The designed automated stent-inspection system utilizes a high-resolution line-scan camera to generate a flat, unrolled view of the stent, and was developed by Carinthian Tech Research CTR-AG. A novel approach is proposed for automatic error detection in stents. Image-processing-based algorithms are applied and work is under way for producing fully automated algorithms. The system generates a large, highly detailed image of the entire stent pattern in a few seconds (typically 20 s and the error detection in 10 to 15 s). Manufacturers of stents can benefit greatly from this new technology, which suits the particular inspection needs of the 100% quality requirement of stent production. The technology continues to evolve and take advantage of the latest developments in the growing field of digital optics, imaging, and computer capabilities.     

DCOM and MMS–based control software architecture for automated manufacturing system

In this paper, we introduce the manufacturing message specification (MMS) and compare two distributed object approaches–distributed component object model (DCOM) and common object request broker architecture (CORBA), suggest characteristics that DCOM is more suitable for automated manufacturing system (AMS) control software integration. In order to make a control system provided with interoperability and reconfigurability etc., a hybrid control system is built for AMS, then a control software architecture is presented for AMS based on distributed object DCOM middleware and MMS standard. The object-oriented DCOM communication protocol is used to implement the MMS in a distributed object mode. DCOM and MMS combination brings the operating system independent communication capabilities to manufacturing devices such as CNC machine tools and industrial robots in AMS. Control software implementation of MMS concepts in the DCOM environment is particularly discussed. Finally, to verify the control software architecture for AMS, prototype development has been implemented in VC++ 6.0 developer environments.     

Monitoring and diagnosis of the tapping process for product quality and automated manufacturing

Tapping has been widely used throughout industry, and its proper operation is paramount in ensuring product quality. Therefore, monitoring and diagnosis are needed to detect the tapping process conditions. They are also important for automated manufacturing. In this work, a combination of ten indices of the tapping process was extracted from tapping torque, thrust force, and lateral forces. The Sequential Forward Search (SFS) algorithm has been used to select the best feature sets. Adaptive Neuro-Fuzzy Inference Systems (ANFIS) were used for the monitoring and diagnosis of tapping process. A 3?×?2 ANFIS structure can distinguish normal tapping process from abnormal tapping process with 100 % reliability. The tapping process conditions can be further classified into five categories with over 95 % success rate using a 10?×?2 ANFIS structure for diagnostic purpose. In simple words, monitoring and diagnosis of tapping process can be carried out successfully using SFS and ANFIS.