Key Enabling Technologies

Key Enabling Technologies

Xun Xu (University of Auckland, NZ)
DOI: 10.4018/978-1-59904-714-0.ch017
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Abstract

While computers have proven to be instrumental in the advancement of product design and manufacturing processes, the role that various technologies have played over the years can never be over-estimated. Because of the intimate involvement of computers in the product development chain, technologies that have severed as enablers are in many cases all software- oriented. There are a number of issues that a technology needs to address in better support of CAD, CAPP, CAM, CNC, PDM, PLM, and so forth. Knowledge acquisition and utilization is one of the top priorities and very often the first step of actions. Intelligent reasoning and optimization is another important task. More often than not, the optimization problems have multi-objectives and multi-constraints that are highly non-linear, discrete, and sometimes fuzzy. Among the technologies that have been developed in the recent past are knowledgebased (expert) system, artificial neural network (ANN), genetic algorithm (GA), agent-based technology, fuzzy logic, Petri Nets, and ant colony optimisation. An expert system is a computer system which includes a well-organized body of knowledge in a bounded domain, and is able to simulate the problem solving skill of a human expert in a particular field. Neural networks are the techniques that can work by simulating the human neuron function, and using the weights distributed among their neurons to perform implicit inference. The genetic algorithms mimic the process of natural evolution by combining the survival of the fittest among solution structures with a structured, yet randomized, information exchange. Agent-based technology utilizes agents as intelligent entities capable of independently regulating, reasoning and decision-making to carry out actions and to achieve a specific goal or a set of goals. This chapter discusses these four technologies together with some applications of these technologies. Also briefly mentioned are the fuzzy logic, Petri Nets, and ant colony optimization methods. The objective is not to give a detailed account for each of these technologies. Instead, the intention is to introduce the technologies that are relevant to and suitable for applications such as CAD, CAPP, CAM, CNC, PDM, and PLM, as well as their integrations. This chapter can also be considered as a focal place for those who are interested in the technologies to further explore, as a collection of over 130 research publications have been cited and are all listed in the reference list at the back.
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Knowledge-Based Systems

In the domain of product design, process planning and manufacturing, multiple types of human expertise and knowledge are needed for various decision-making processes. This explains why knowledge-based systems are among the most researched technologies, and in many cases have proven to be effective systems.

Expert Systems Technology

Expert system (otherwise known as knowledge-based system) is an important branch of artificial intelligence (AI). Expert systems provide a natural, yet powerful and flexible means for obtaining solutions to a variety of manufacturing problems that often cannot be dealt with by other more orthodox methods. One study reported an investment of over $100 million in artificial intelligence research by large American manufacturing companies. Some of them have achieved impressive results (Dornan, 1987). Among the companies that benefited the most are Digital Equipment Corporation’s XCON, Boeing and Lockheed Georgia Corporation’s GenPlan. It is of the view of many that expert systems can make a significant contribution to improving process and production planning (Kusiak & Chen, 1988, Badiru, 1992, Jayaraman & Srivastava, 1996, Zhang & Chen, 1999).

Welbank (1983) defines an expert system as a program that has a wide base of knowledge in a restricted domain, and uses complex inferential reasoning to perform tasks, as human expert usually does. In other words, an expert system is a computer system containing a well-organised body of knowledge, which emulates expert problem solving skills in a bounded domain of expertise. The system is able to achieve expert levels of problem solving performance, which would normally be achieved by a skilled human when confronted with significant problems in the domain. As illustrated in Figure 1, an expert system consists of three main components, the knowledge base, inference engine and user interface.

Figure 1.

Expert system’s architecture

Knowledge base is the heart of the system. It contains the knowledge needed for solving problems in a specific domain. Knowledge may be in the form of facts, heuristics (e.g. experiences, opinions, judgments, predictions, algorithms) and relationships usually gleaned from the mind of experts in the relevant domain. Knowledge may be represented using a variety of representation techniques (e.g. semantic nets, frames, predicate logic) (Jackson, 1986, Ignizio, 1991, Mital & Anand, 1994), but the most commonly used technique is “if-then” rules, also known as production rules. These rules are often represented in a tabulated form. The inference engine is employed during a consultation session to examine the status of the knowledge base, handle the content of the knowledge base and determine the order in which inferences are made. It may use various inference methods. The user interface part enables interaction of the system with the user. It mainly includes screen displays, a consultation/ advice dialogue and an explanation component. In addition, expert systems provide interfaces for communication with external programs such as databases and spreadsheets.

Complete Chapter List

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Dedication
Table of Contents
Foreword
A.Y.C. Nee
Acknowledgment
Xun Xu
Chapter 1
Xun Xu
One of the key activities in any product design process is to develop a geometric model of the product from the conceptual ideas, which can then be... Sample PDF
Geometric Modelling and Computer-Aided Design
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Chapter 2
Xun Xu
Today, more companies than ever before are involved in manufacturing various parts of their end products using different subcontractors, many of... Sample PDF
CAD Data Exhange and CAD Standards
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Chapter 3
Xun Xu
Products and their components are designed to perform certain functions. Design specifi- cations ensure the functionality aspects. The task in... Sample PDF
Computer-Aided Process Planning and Manufacturing
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Chapter 4
Feature Technology  (pages 75-89)
Xun Xu
Throughout the course of the development of CAD, CAPP, and CAM systems, unambiguous representation of a design’s geometry and topology remain an... Sample PDF
Feature Technology
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Chapter 5
Feature Recognition  (pages 90-108)
Xun Xu
Conventional CAD models only provide pure geometry and topology for mechanical designs such as vertices, edges, faces, simple primitives, and the... Sample PDF
Feature Recognition
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Chapter 6
Feature Interactions  (pages 109-125)
Xun Xu
Feature interaction tends to have a wide range of consequences and effects on a feature model and its applications. While these may often be... Sample PDF
Feature Interactions
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Chapter 7
Xun Xu
Integrated feature technology promotes a closer connection between design and manufacturing through features. When machining features are... Sample PDF
Integrated Feature Technolog
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Chapter 8
CNC Machine Tools  (pages 165-187)
Xun Xu
The introduction of CNC machines has radically changed the manufacturing industry. Curves are as easy to cut as straight lines, complex 3-D... Sample PDF
CNC Machine Tools
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Chapter 9
Program CNCs  (pages 188-229)
Xun Xu
A CNC machine can be programmed in different ways to machine a workpiece. In addition to creating the cutting program, many other factors also need... Sample PDF
Program CNCs
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Chapter 10
Xun Xu
Technologies concerning computer-aided design, process planning, manufacturing and numerical control, have matured to a point that commercialized... Sample PDF
Integration of CAD/CAPP/CAM/CNC
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Chapter 11
Xun Xu
The integration model (Model B) as discussed in the previous chapter makes use of exchangeable neutral data formats such as IGES (1980). Neutral... Sample PDF
Integration Based on STEP Standards
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Chapter 12
Xun Xu
Function blocks are an IEC (International Electro-technical Commission) standard for distributed industrial processes and control systems (IEC... Sample PDF
Function Block-Enabled Integration
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Chapter 13
Xun Xu
In order to prepare manufacturing companies to face increasingly frequent and unpredictable market changes with confidence, there is a recognized... Sample PDF
Development of an Integrated, Adaptable CNC System
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Chapter 14
Xun Xu
A logical step after CNC machining is inspection. With inspections, Closed-Loop Machining (CLM) can be realized to maximize the efficiency of a... Sample PDF
Integrating CAD/CAPP/CAM/CNC with Inspections
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Chapter 15
Xun Xu
Today, companies often have operations distributed around the world, and production facilities and designers are often in different locations.... Sample PDF
Internet-Based Integration
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Chapter 16
Xun Xu
Companies that have been practicing CAD, CAPP, CAM, and CNC integration have now realized that there is a need to operate in a much broader scope... Sample PDF
From CAD/CAPP/CAM/CNC to PDM, PLM and Beyond
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Chapter 17
Key Enabling Technologies  (pages 354-393)
Xun Xu
While computers have proven to be instrumental in the advancement of product design and manufacturing processes, the role that various technologies... Sample PDF
Key Enabling Technologies
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