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1.
Fixture design plays an important role at the planning stage before shop-floor production. A desired fixture design can be employed to hold the workpart securely so that slippage and excessive deformation can be prevented during machining. Therefore, appropriate fixturing contributes highly to machining quality. To reduce lead time and the human effort devoted to fixture planning, computer-aided fixture design (CAFD) is required. In this paper, a CAFD system consisting of three modules, i.e. Fixture Data Management, Fixture Element Selection and Fixture Layout Design, is developed. According to fixture feature recognition and classification, a comprehensive fixture database in the Fixture Data Management module is constructed to maintain efficiently the fixture-related data. The domain of the fixture database consists of modular mechanical fixtures, modular hydraulic fixtures and modular V-blocks. After expertise extraction, suitable fixture elements can be automatically selected according to the machining conditions in the Fixture Element Selection module. Finally, by integrating previous reasoning algorithms, fixturing locations and orientations are determined. Feasible fixture layouts that meet manufacturing and inspection specifications can be generated in the Fixture Layout Design module. The prototype system is implemented under commercial CAD and database management system (DBMS) software. Comprehensive fixture databases and a rule-based knowledge base are built to provide effective data management. The paper aims to propose a systematic CAFD framework and application system to provide efficient decision support for different types of fixture planning. 相似文献
2.
An index system to exploit similarities among workpiece shapes or locating methods in modular fixtures is proposed in this paper. It is developed to apply to case-based reasoning (CBR) technology. An index system signifies all the important characteristics to classify a number of parts to different groups. Each group is identified by a multiple digit alphanumeric code. A seven-digit code is designed in this study to represent and classify the modular fixtures. Using this index system, past experience in modular fixture design is saved and then the design is also simplified by referring to past design cases. A CBR system, based on this index system, has been developed to assist in modular fixture design. 相似文献
3.
The capability of a flexible manufacturing system to meet the demands for small to medium size batch production can be limited by component fixturing requirements. The rule-based method illustrated could lead to an optimum solution for the fixture design problem. To illustrate the approach proposed, the system has been used to design a fixture for a real, although simple, prismatic engineering component. 相似文献
4.
Checking fixture design is a complicated task requiring a strong professional background and rich practical experience. In order to enhance design efficiency and quality, this paper proposes a computer-aided checking fixture design methodology. The key issues include a new minimal volume bounding box generation approach for workbench design, a multi-objective optimisation algorithm of locator layout for location design, a multi-surface extension and transition method for checking components design and a flexible part library system to reuse standard parts and to assemble them automatically. As an implementation of the system based on the key methods, Checking Fixture Design Wizard for automobile parts, a plug-in on CAD software, is developed. Finally, a car door checking fixture design is taken as a case study to verify its feasibility and practicability. 相似文献
5.
结构主动控制的一体化多目标优化研究 总被引:1,自引:0,他引:1
基于Pareto多目标遗传算法提出了结构主动控制系统的一体化多目标优化设计方法,对作动器位置与主动控制器进行同步优化设计.外界激励采用平稳过滤白噪声来模拟,在状态空间下通过求解Lyapunov方程,得到结构响应和主动控制力的均方值.主动控制器采用LQG控制算法来进行设计.以结构位移和加速度均方值最大值与相应无控响应均方值的最大值之比,以及所需控制力均方值之和作为多目标同步优化的目标函数.优化过程还考虑了结构与激励参数对优化结果的影响.最后以某6层平面框架有限元模型为例进行了计算机仿真分析,结果表明所提出的主动控制系统多目标一体化优化方法简单,高效,实用,具有较好的普适性. 相似文献
6.
This paper describes the design and development of a low cost shop floor control system for the modular furniture industry. An architecture in five hierarchical levels has been selected. An overview of the functions performed by line and workstation levels are described, likewise that information system part related with the control system. A detailed discussion about line level is presented and principally the incorporation of a Schedule Manager, based on an expert system. The proposed line level architecture and the software tools used in its implementation give a greater flexibility to the line control system. 相似文献
7.
This paper investigates the problem of ordering and pricing over a finite time planning horizon for an inventory system with
advance sales and spot sales. It is assumed that the planning horizon is divided into several sales cycles each of which is
divided into an advance sales period and a spot sales period. During the advance sales period, all customers are required
to make reservations for their orders and will receive them at the arrival time of the replenishment orders. In the case of
the spot sales periods, all customers receive their orders at the time of the purchase. In actual practice, since customers
with reservations may cancel their orders before receiving them, this paper considers this phenomenon and develops a continuous
time inventory model to deal with the proposed problem. This paper maximizes the total profit over a finite time planning
horizon by determining the optimal advance sales price, spot sales price, order size, and replenishment frequency. Analysis
of results shows that a simple algorithm can be developed to arrive at an optimal decision. 相似文献
8.
9.
Quality and reliability information integration for design evaluation of fixture system reliability 总被引:1,自引:0,他引:1
Quality and reliability are two important factors in manufacturing‐system design. However, the analysis and optimization of manufacturing‐system reliability and product quality are normally conducted separately in practice. There is no general framework to integrate these two important factors, quantitatively analyze the interactions between them, and further study their integrated effects on the manufacturing‐system performance. In this paper, the QR‐Co‐Effect of product/part quality and manufacturing‐system component reliability is investigated in an assembly fixture system. The concept, model and analysis of QR‐Co‐Effect are addressed in this paper. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
10.
介绍了集成化运输包装设计系统的需求,提出了系统模型,基于此模型分析和研究了各个模块的设计流程。设计的集成化运输包装系统可以完成产品的缓冲设计、纸箱设计和托盘设计,并对方案进行组合、优化和优选。设计了系统数据库,提出了系统总体设计流程。 相似文献
11.
Abstract Due to the varying time and the complexity of the commercial telecommunication network configuration, routing of the communication traffic becomes very important for telecommunication systems. No one can keep in mind all the complex routing plans used in networks, so it is hard to quickly take proper actions while the switching node is being blocked. In this paper, we propose an expert system which can collect traffic data, monitor network status, reason and take appropriate actions for extreme traffic congestion on a network just as a network management expert can do. It would certainly streamline the whole network control procedure, and. provide dynamic routing functions based on the original static routing method adopted in Taiwan. It does improve both network efficiency and network reliability. 相似文献
12.
This paper is based upon the premise that computers can do more than just ‘number crunching’ to assist a designer in his task. Key features of the design process where traditional computer-aided design (CAD) approaches have had limited success are presented. The approach of expert systems, which shows promise of assisting in these features, is outlined and a system based on this approach, DESIGNER, described. This system can be applied to any numerical design problem and is illustrated through an example from preliminary ship design. 相似文献
13.
This paper focuses on pricing strategies, inventory policies for a supply chain when Radio Frequency Identification (RFID) technology is adopted to cope with inventory inaccuracy. The supply chain consists of one supplier and one retailer, in which the RFID tag price is shared between the supplier and the retailer. We present and compare the performance differences between a wholesale price contract and a consignment contract when the retailer is the Stackelberg leader and the supplier is the follower. Based on the optimal pricing and inventory decisions, an interesting observation of contract selection is that there are two critical values of inventory available rate such that when the inventory availability is less than the lower value, both the supplier and the retailer prefer a consignment contract; when the inventory availability is greater than the upper value, a wholesale price contract is their best choice; when the inventory availability is between the two values, the supplier prefers a wholesale price contract and the retailer prefers a consignment contract. Additionally, there exist threshold values of RFID tag price and sharing rate to determine the contract preference for the retailer. Furthermore, the profits of both the supplier and the retailer are independent of the RFID tag price sharing rate in a wholesale price contract, and the supplier has the incentive to invest in RFID tag cost in a consignment contract. 相似文献
14.
15.
EDWARD A. SILVER 《国际生产研究杂志》2013,51(6):647-671
There are frequent occasions where the coordination of replenishment orders for selected groups of items can lead to significant savings in the costs of replenishment. This paper is concerned with a practical procedure for selecting the order-up-to-levels, can-order points and must-order points of a particular coordinated control system. Demand is Foisson and a fixed non-zero replenishment lead time is assumed. Cost comparisons with the best independent control strategy indicate that substantial savings (averaging 18-8% over some 104 examples) are possible through coordination. 相似文献
16.
In price-sensitive markets, price promotions coupled with an appropriate item replenishment strategy can be effective in controlling
the total costs of servicing the market. In supply chains that handle perishable products, inventory management is already
a complex problem and the management of products in a dynamic-pricing environment is even more challenging. Monitoring and
control of time-sensitive products can be facilitated by the application of radio frequency identification (RFID) technology,
which enables non-contact, real-time data collection and efficient interfacing with the management control system in the supply
chain. This paper describes an integrated framework for inventory management and pricing in a discrete time (periodic review
and ordering) framework, and describes an efficient algorithm, including a new approximation, for the related optimization
problem. We then propose a suitable architecture for the application of RFID technology in this context, to realize the potential
benefits. 相似文献
17.
Ying Wei 《OR Spectrum》2012,34(1):243-271
This paper studies a periodic review dynamic pricing and inventory control problem with fixed ordering cost included. Demand
is uncertain and price-sensitive in a general form. At the end of each period, all unmet demand is lost. We focus on the optimization
and optimality of an (s, S, p)-type policy, which operates as follows: whenever the inventory level is less than or equal to s, an order is placed to order-up-to level S; when the inventory level is larger than s, no order is issued; the price p is specified by the inventory level. We further numerically investigate the optimal solutions and their sensitivity to cost
parameters and demand uncertainty. 相似文献
18.
Motivated by the practice of airlines, this paper considers the following problem. Tickets are offered at a limited number of predetermined price levels, and the price is only allowed to change monotonically. Management needs to determine the number of seats to be sold at each discount fare with an objective of maximizing the revenue. Such a semi-dynamic pricing and seat allocation approach improves the static pricing approach, as it allows a certain degree of pricing flexibility, but it compromises the potential revenue maximization of the dynamic pricing approach. Therefore, a natural question is what is the magnitude of the revenue loss by such a semi-dynamic approach? The primary objective of this paper is to gain insights into this question. Based on structural results, numerical experiments show that the semi-dynamic pricing approach generates near-optimal revenue. 相似文献
19.
Implementation of flexible manufacturing technology in the batch manufacturing environment has created major problems for designers and engineers who are responsible for specification and design of flexible manufacturing systems (FMS). The FMS design task appears to be an excellent application for expert systems techniques. This paper describes current results of an ongoing research effort to develop an expert system which analyses the output from an FMS simulation model, determines whether operational and financial objectives are met, identifies design deficiencies or opportunities for improvement, and proposes designs which overcome deficiencies or exploit improvement opportunities. An overview of the FMS design expert system is given and a case study is presented to illustrate how the system operates. Areas for future research are also discussed. 相似文献
20.
Genetic algorithm based deformation control and clamping force optimisation of workpiece fixture system 总被引:1,自引:0,他引:1
K. Siva Kumar 《国际生产研究杂志》2013,51(7):1903-1935
In re-engineering mass production industry, design and production of components are frequently changed according to the customer needs within a very short span of time. This leads to rising difficulty in maintaining the accuracy of every finished component. It also induces the long setup time of the cutting tools and machine tools affecting the production rate of the components. To reduce the production time and to improve the accuracy of the finished product, proper fixture element is essential. The accuracy of the finished work-piece strongly depends on the position of the locators and clamps in the work-piece fixture system. The finite element analysis tool is well suited to predict the active and passive forces on the work piece-fixture system. The accuracy of the workpiece not only depends on the clamping force but also depends upon the locator force (reaction force). This paper presents the optimisation of the locations of active (clamp) and passive (locator/support) elements in the workpiece-fixture system using genetic algorithm (GA) with ANSYS parametric design language (APDL) of finite element analysis. Three case studies are given to illustrate the application of the proposed approach. Finally the case study results have been compared with the Li and Melkote (1999a) [Li, B. and Melkote, S.N., 1999a. An elastic contact model for the prediction of workpiece-fixture contact forces in clamping. ASME Journal of Manufacturing Science and Engineering, 121(3), 485–493] study. This presented prediction method is conceptually simple and computationally efficient. 相似文献