模具企业生产调度管理系统的研究

为适应模具企业新的生产方式,本文提出了一种结合合同网协议、GPGP协同机制和TAEMS任务描述语言的任务分配和调度方法,并建立层/级结构的整体框架和各级调度策略.该方法从整体的角度分析问题,提高了调度结果的一致性和优化性.初步的验证表明该方法是有效的.     

基于仿真的单元化制造系统层次建模技术研究

参考ISO和NBS的企业自动化系统的层次模型,自顶向下将单元化制造系统依次划分为车间层、单元层和设备层,降低了模型的复杂性.建立了基于Petri网的层次模型,将其转化为eM-Plant仿真模型,提高了模型的重用性.对某生产车间,建立了层次化的仿真模型,使用不同的调度策略进行仿真,试验证明了模型的高效性和合理性.     

Cellular machine layout based on the Segmented Flow Topology

This paper introduces a facility layout design procedure for converting an existing manufacturing system with a predefined aisle structure to a cellular manufacturing system based on the 'segmented flow topology' (SFT) developed by Sinriech and Tanchoco. The proposed procedure is aimed at finding the best machine grouping, along with the locations of pick-up and delivery stations and machine layout for each cell based on an existing facility. The objective is to minimize the total material handling cost. In contrast to previous work in this area, the proposed design procedure takes into account both distance and material flow in forming machine clusters. In addition, a revised cost model for material handling system, which accounts for different aspects of capital and operating cost, is presented.     

A two-layer dynamic scheduling method for minimising the earliness and tardiness of a re-entrant production line

This study focuses on the dynamic scheduling problem of a re-entrant production line, in which all of the parts are assumed to have the same processing routes and be processed on every machine. A two-layer dynamic scheduling method is proposed for the dynamic scheduling of the re-entrant line with the objective of minimising total earliness and tardiness. This method consists of two layers. The top layer is to select the appropriate scheduling policy, and the bottom layer is to generate the scheduling by using the policy selected in the top layer. In the top layer, three different rules are constructed for selecting scheduling policies, namely the lateness comparison rule, the lateness variation comparison rule, and the equal interval switching rule. In the bottom layer, three different scheduling policies are proposed to generate the real-time scheduling for manufacturing, namely the FCFS (first come first service) scheduling policy, the PI (proportional-integral) scheduling policy, and the fuzzy PI scheduling policy. Considering that the real-time status of manufacturing changes constantly, it is necessary to switch among different scheduling policies to adapt to this change. Numerical experiments are performed in the situations with and without urgent jobs. The results show that the proposed two-layer dynamic scheduling method outperforms any single scheduling policy (e.g., the FCFS policy, the PI policy and the fuzzy PI policy) for the dynamic scheduling of a re-entrant production line.     

Impact of the use-based maintenance policy on the performance of cellular manufacturing systems

In this paper, a multi-objective integer programming approach is developed to investigate the impact of the use-based preventive maintenance (UPM) policy on the performance of the cellular manufacturing system (CMS). Under the UPM policy a maintenance schedule is established which provides for the performance of preventive maintenance (PM) only after a predetermined number of operating hours of machine use. This research indicates how PM and failure repair (FR) actions affect the effective availability of the machines and accordingly the machine and inter/intra-cell material handling costs under the UPM policy. The objective is to minimise the machine cost, inter- and intra-cell material handling and PM/FR costs. The proposed model is solved by an interactive fuzzy programming (IFP) approach to determine the best compromise solution from the decision maker point of view. IFP assumes that each objective function has a fuzzy goal and focuses on minimising the worst upper bound to obtain an efficient solution which is close to the best lower bound of each objective function. Compromise solutions are prioritised by two efficiency criteria, i.e. grouping efficiency and system availability. The performance of the proposed model is verified by a comprehensive numerical example.     

A framework for characterising energy consumption of machining manufacturing systems

Energy consumption in machining manufacturing systems is increasingly of interest due to concern for global climate change and manufacturing sustainability. To utilise energy more effectively, it is paramount to understand and characterise the energy consumption of machining manufacturing systems. To this end, a framework to analyse energy consumption characteristics in machining manufacturing systems from a holistic point of view is proposed in this paper. Taking into account the complexity of energy consumption in machining manufacturing systems, energy flow is described in terms of three layers of machining manufacturing systems including machine tool layer, task layer and auxiliary production layer. Furthermore, the energy consumption of machining manufacturing systems is modelled in the spatial and temporal dimensions, respectively, in order to quantitatively characterise the energy flow. The application of the proposed modelling framework is demonstrated by employing a comprehensive analysis of energy consumption for a real-world machining workshop. The characteristics of energy consumption for machine tool layer, task layer and auxiliary production layer are, respectively, obtained using quantitative models in the spatial and temporal dimensions, which provides a valuable insight into energy consumption to support the exploration of energy-saving potentials for the machining manufacturing systems.     

FMS中的DNC系统实时控制软件的设计与实现

为了使柔性制造系统(FMS)中的DNC系统的上位机能同时实时控制多台数控机床(CNC),在利用5层OSI网络协议模型分析FANUC DNC2协议原理的基础上,利用面向对象的程序设计方法进行了FMS中的DNC系统实时控制软件的设计,同时构建了其硬件结构,实现了该软件的开发。在上海交通大学CIMS中心的FANUC 16-MC机床的现场使用表明,所开发的软件运行可靠,使用方便。     

Integer programming models for the re-entrant shop scheduling problems

A re-entrant shop describes a manufacturing environment in which a machine can process a job more than once. A re-entrant shop can be classified into a re-entrant job-shop (RJS) and a re-entrant flow-shop (RFS). This article presents the development of the mixed binary integer programming (BIP) technique for the RJS and the RFS scheduling problems. Eight mixed BIP models are proposed for solving re-entrant shop scheduling problems to minimize makespan. The models RJS-1, RJS-2, RJS-3, and RJS-4 are for the RJS problems, while the other four models (RFS-1, RFS-2, RFS-3, and RFS-4) are for the RFS problems. Computational results show that the RJS-4 model is the best of the RJS models, and the RFS-3 model is the best of the RFS models.     

Performance analysis of re-entrant manufacturing networks under surplus-based production control

Motivated by the problem of planning and scheduling in large semiconductor manufacturing facilities we study the performance of re-entrant production networks. In such networks, each product has to go multiple times through the entire manufacturing line before it is ready. Each machine in a re-entrant network can receive products from different routings, but the products from only one of the routings can be served at a time. This complicated network structure makes it difficult, and at the same time important, to estimate in advance the performance of such a network under a demand-driven control policy. In this paper we present results on the influence of perturbations, buffer inventory levels and the number of manufacturing stages on the production tracking error of each machine in the re-entrant network operated under a surplus-based production control policy. The results are provided in the form of so-called ‘worst case scenario’ bounds on the steady-state production demand tracking accuracy of each stage as well as bounds on the content of each intermediate inventory level. By means of simulation examples we show that the results obtained have an important meaning and can be used as a practical reference tool.     

基于坐标变换的功能梯度材料空间映射建模研究

随着3D打印零件复杂性和多样性的日益增加,单一材质的零件已无法满足各类特殊性能要求,功能梯度材料零件逐渐成为快速成型制造行业的研究热点。为满足功能梯度材料的制造要求,提出了一种基于坐标变换的功能梯度材料空间映射建模方法,该方法的关键是将几何信息与材料信息有效结合。首先,采用单梯度源法、多梯度源法构建功能梯度材料模型的材料空间,在遇到交叉梯度源模型时利用特定的相交算子以一定的权重比进行材料分布计算。然后,在几何空间与材料空间结合的过程中,巧妙地通过坐标变换将材料空间与几何空间的坐标系重合,实现将材料空间映射至几何空间,从而得到带有材料信息的功能梯度材料模型。通过修改梯度源、材料分布函数以及坐标变换方法即可获得所需的功能梯度材料模型。利用Visual Studio 2019软件和OpenGL编程语言对实例模型进行可视化分析的结果表明,所提出的建模方法相比于大部分估值建模、非估值建模方法可大大缩短建模时间,从根本上解决了某些算法所造成的储存空间不足和建模过程繁琐等问题。基于坐标变换的功能梯度材料空间映射建模方法为增材制造行业提供了一种新的建模方法,具有良好的应用价值。     

An agent-based negotiation approach to integrate process planning and scheduling

This paper presents the development of an agent-based negotiation approach to integrate process planning and scheduling (IPPS) in a job shop kind of flexible manufacturing environment. The agent-based system comprises two types of agents, part agents and machine agents, to represent parts and machines respectively. For each part, all feasible manufacturing processes and routings are recorded as alternative process plans. Similarly, alternative machines for an operation are also considered. With regard to the scheduling requirements and the alternative process plans of a part, the proposed agent-based IPPS system aims to specify the process routing and to assign the manufacturing resources effectively. To establish task allocations, the part and machine agents have to engage in bidding. Bids are evaluated in accordance with a currency function which considers an agent's multi-objectives and IPPS parameters. A negotiation protocol is developed for negotiations between the part agents and the machine agents. The protocol is modified from the contract net protocol to cater for the multiple-task and many-to-many negotiations in this paper. An agent-based framework is established to simulate the proposed IPPS approach. Experiments are conducted to evaluate the performance of the proposed system. The performance measures, including makespan and flowtime, are compared with those of a search technique based on a co-evolutionary algorithm.     

The development of a visual interactive simulation of packaging flow lines

The design and implementation of new manufacturing processes or the reconfiguration/reuse of existing machines is a multidisciplinary activity. The introduction and modification of processes requires input from a variety of people with disparate skills, backgrounds, responsibilities and requirements. In addition, the trend towards globalization of businesses has resulted in collaborative projects involving domain experts who speak different languages and originate from different cultural backgrounds. Clearly effective communication via common representations is essential in such projects. A visual interactive simulation that can easily be modified (i.e. reconfigured, extended or reused) is an effective method of providing a common representation for personnel involved in the design and implementation of manufacturing processes. In this paper the development of a visual interactive simulation is discussed with regards to the problem of investigating the operation and interoperation of a number of workstations that comprise a beverage can production flow line. A consortium of European partners was involved in the project to determine the opportunities to increase the efficiency of the current operation with respect to material usage and machine operational efficiency.     

Decomposition in automatic generation of Petri nets for manufacturing system control and scheduling

Despite the efforts in developing Petri net models for manufacturing control and scheduling, the generation of Petri net models cannot be automated for agile manufacturing control and scheduling without difficulties. The problems lie in the complexity of Petri net models. First of all, it is difficult to visualize the basic manufacturing process flow in a complex Petri net model even for a Petri net modelling expert. The second problem is related to the complexity of using Petri net models for manufacturing system scheduling. In this paper, a decomposition methodology in automatic generation of Petri nets for manufacturing system control and scheduling is developed. The decomposition methodology includes representing a manufacturing process with the Integrated Definition 3 (IDEF3) methodology, decomposing the manufacturing process based on the similarity of resources, transforming the IDEF3 model into a Petri net control model, and aggregating sub Petri net models. Specifically, a sequential cluster identification algorithm is developed to decompose a manufacturing system represented as an IDEF3 model. The methodology is illustrated with a flexible disassembly cell example. The computational experience shows that the methodology developed in this paper reduces the computational time complexity of the scheduling problem without significantly affecting the solution quality obtained by a simulated annealing scheduling algorithm. The advantages of the methodology developed in this paper include the combined benefits of simplicity of the IDEF3 representation of manufacturing processes and analytical and control properties of Petri net models. The IDEF3 representation of a manufacturing process enhances the manmachine interface.     

虚拟加工环境中标准化通信的研究与实现

通过在虚拟加工环境中实现基于MMS（制造报文规范）的标准化通令系统,探讨了虚拟制造平台实现网络集成的方法。介绍了MMS协议的内容,提出了系统的总体框架,并详细描述了基于MMS协议的通信支持系统与虚拟设备相连的服务接口系统的实现方法、框架结构和程序执行流程。     

用于不同规格瓷器包装的通用自动化系统设计

目的 根据瓷器怕摔易碎的特性,针对各种不同规格瓷器的包装工艺,设计一种通用的瓷器即时包装自动化系统.方法 为了适应不同规格的瓷器包装,该系统采用红外扫描的方式检测瓷器外形,设计3种全自动工作模式.采用笛卡尔坐标系原理,应用旋转平台和双自由度喷枪实现了瓷器的三维全方面包装.采用大功率舵机精确控制喷枪的喷发时刻和喷发强度,该系统还具有限位报警和发泡剂流量控制的功能,保证系统工作的稳定性,提高系统的实用性.结果 通过流量控制试验,解决了喷枪流量稳定性差和包装层衔接不均匀问题,实验结果表明,喷枪开关角度越大,喷发直径越大,发泡剂喷发效果越好.现场瓷器包装实验,验证了该系统的有效性.结论 该包装系统打破了现在包装机器只能包装固定外形瓷器的格局,实现了一机通用,实现了现场即时包装.该系统自动化程度高,包装质量好,包装效率高,成本低,提高了包装行业的经济效益.     

Modeling and identification of the multi-axis drive system using support vector machine and granular computing

Advanced manufacturing technology requires high-precision capability in multi-axis computer numerical control (CNC) machine tools. At present, the modeling and identification for the drive system of CNC machine tools has some defects. In order to solve the problem, some interdisciplinary theories and methods, such as support vector machines, granular computing, artificial immune algorithms, and particle swarm optimization algorithms, have been used to model and identify multi-axis drive systems for CNC machine tools. An identification method using a support vector machine, based on granular computing, is presented to identify a multi-axis servo drive system model for improving the precision of model identification, and an immune particle swarm optimization algorithm, based on crossover and mutation functions, is proposed to optimize the structure parameters of the support vector machine based on granular computing. The proposed identification method was evaluated by experiments using the multi-axis servo drive system. The experimental results showed that the proposed approach is capable of improving modeling and identification precision.     

A formal control-theoretic model of a human–automation interactive manufacturing system control

This paper describes a human–automation interactive manufacturing system and presents a formal model for describing and controlling the system. The model presented in this paper considers a system from two perspectives: structural and operational perspectives. Human and an automated controller are considered agents that cooperate to achieve given goals by executing assigned tasks. A human–automation interaction is described with a particular communication model between two agents that exchanges messages. A system control schema and human tasks are modelled separately and then integrated in a formal manner using a modified communicating finite state machine framework. An interface model that coordinates the message exchanges between two agents is then introduced. An automated shop floor control system with a human material handler is modelled with the proposed framework and a simple illustrative example is provided.     

A deep learning approach for the dynamic dispatching of unreliable machines in re-entrant production systems

This research combines deep neural network (DNN) and Markov decision processes (MDP) for the dynamic dispatching of re-entrant production systems. In re-entrant production systems, jobs enter the same workstation multiple times and dynamic dispatching oftentimes aims to dynamically assign different priorities to various job groups to minimise weighted cycle time or maximise throughput. MDP is an effective tool for dynamic production control, but it suffers from two major challenges in dynamic control problems. First, the curse of dimensionality limits the computational performance of solving large MDP problems. Second, a different model should be built and solved after system configuration is changed. DNN is used to overcome both challenges by learning directly from optimal dispatching policies generated by MDP. Results suggest that a properly trained DNN model can instantly generate near-optimal dynamic control policies for large problems. The quality of the DNN solution is compared with the optimal dynamic control policies through the standard K-fold cross-validation test and discrete event simulation. On average, the performance of the DNN policy is within 2% of optimal in both tests. The proposed artificial intelligence algorithm illustrates the potential of machine learning methods in manufacturing applications.     

Optimal control of a continuum model for single-product re-entrant manufacturing systems

A semiconductor manufacturing system that involves a large number of items and many steps can be modelled through conservation laws for a continuous density variable on a production process. In this paper, the basic hyperbolic partial differential equation (PDE) models for multiple re-entrant manufacturing systems are proposed. However, through numerical examples, the basic continuum models do not perform well for small-scale multiple re-entrant systems, so a new state equation taking into account the re-entrant degree of the product is introduced to improve the basic continuum models. The applicability of the modified continuum model is illustrated through a numerical example. Based on the modified continuous model, this paper studies the optimal control problems for multiple re-entrant manufacturing systems. The gradient of the cost function with respect to the influx is solved by the adjoint approach, and then the optimal influx is computed by the steepest descent method. Finally, numerical examples on optimal influx profiles for steps in demand rate, linear demand rate and periodically varying demand rate are given. The relationships among influx, outflux and demand are also discussed in detail.     

支持多应用的统一制造资源模型研究

支持多应用的统一制造资源模型是实现资源数据集成、加强应用的深度和广度以及实现企业整体资源优化的基础.从信息完整性、管理与应用以及企业个性化要求等多个角度分析了统一制造资源建模的需求,提出了资源元数据模型的概念,将资源数据分解为资源实体、资源类型、资源组合、资源视图与资源能力五个方面进行描述,在此基础上提出了统一制造资源信息模型(UMRIM)框架,该框架由资源核心模型层、应用模型层和整体优化模型层构成.基于UMRIM和面向服务架构的模式建立了资源服务平台,给出了平台的结构.