Heuristic Design of a Material Processing Component

The main thrust of this research is in developing a knowledge-based system for the design of a mechanical engineering process. The study concentrates on developing methodologies for initial design and redesign in a qualitative format. The component selected is a die for plastic extrusion. A design algorithm using best first heuristic search and expert knowledge, both in procedural and declarative form, forms the core of the process. Initial design and redesign methodologies are presented that can enable efficient design of a component using expert knowledge. Some generality has been accomplished by the implementation of the techniques to dies of different cross sectional shapes. The software is written in Lisp within an object oriented software package using analysis modules written in C.

Subjective Design Evaluation With Multiple Attributes

A formal methodology is presented which may be used to evaluate design alternatives in the iterative design/redesign process. Deterministic multiattribute utility analysis is used to compare the overall utility or value of alternative designs as a function of the levels of several performance characteristics of a manufactured system. The evaluation function reflects the designers subjective preferences. Sensitivity analysis provides quantitative information as to how a design should be modified in order to increase its utility to the design decision maker. Improvements in one or more areas or performance and tradeoffs between attributes which would increase desirability of a design most may be quantified. A case study of materials selection and design in the automotive industry is presented. The methodology was applied to 6 automotive companies in the United States and Europe, and results are used to illustrate the steps followed in application.

Proving the Labeled Interval Calculus for Inferences on Catalogs

The “labeled interval calculus” is a formal system that performs quantitative inferences about sets of artifacts under sets of operating conditions. It refines and extends the idea of interval constraint propagation, and has been used as the basis of a program called a “mechanical design compiler,” which provides the user with a “high level language” in which design problems for systems to be built of cataloged components can be quickly and easily formulated. The compiler then selects optimal combinations of catalog numbers. Previous work has tested the calculus empirically, but only parts of the calculus have been proven mathematically. This paper presents a new version of the calculus and shows how to extend the earlier proofs to prove the entire system. It formalizes the effects of toleranced manufacturing processes through the concept of a “selectable subset” of the artifacts under consideration. It demonstrates the utility of distinguishing between statements which are true for all artifacts under consideration, and statements which are merely true for some artifact in each selectable subset.

Design Theory and Methodology in Eastern Europe

The paper provides a brief review of general tendencies and interesting developments in the area of engineering design theory and methodology in Eastern Europe. This review is limited to East Germany, Poland, and the Soviet Union. Particular attention was given to the design research environments in individual countries, and to developed design theories and methods in the context of these environments.

Research in Design Theory and Methodology in West Germany

Current research in design methods in the Federal Republic of Germany is reviewed. VDI guideline 2221 is discussed. The paper looks at basic research in design theory and methodology, application of the methodology to computer-aided conceptual and embodiment design, development of intelligent CAD systems, use of expert systems in CAD, and understanding thought processes in designing. References to the publications of the past three years are given.

Design Science: Meta-Science to Engineering Design

Following on from a paper presented at a previous Design Automation Conference (Eder 1986), this paper outlines some of the more recent insights concerning engineering design that have been developed by a small international group. Some of the models of designing and technical systems have been improved. A morphology of knowledge about designing and technical systems has been proposed, and extended to a morphology of knowledge itself. Some consequences are drawn from these developments, and summarized in this paper.

Engineering Design: A Perspective on U.K. and Swiss Developments

Historic developments, and the current state of the art are surveyed in thought, theory, methods and methodology, and education for and about engineering design. This survey covers two particular and disparate regions, the United Kingdom, and Switzerland, the latter including the activities of an international group centered in Zürich known as WDK — Workshop Design-Konstruktion.

Two Robust, Point-in-Polygon Tests Based on the 4 × 4 Determinant Method

Two new, contrastive point-in-polygon algorithms based on the 4 × 4 determinant method are proposed. By employing the error-free computations of the 4 × 4 determinant method, the algorithms can be very robust. First, a brief introduction to the 4 × 4 determinant method is presented. Secondly, the ideas of reconstructing, in two contrastive ways, a polygon from a sequence of point data are explained and then two algorithms derived from the ideas are presented. Thirdly, characteristics of both algorithms are discussed and compared. The complete programs of the two algorithms are shown.

An Intelligent Interactive Layout CAD System for Industrial Plants

This paper describes an industrial plant layout system with an intelligent interactive user-interface. This system offers a powerful design environment, in which a designer can concurrently draw and check a layout plan, which can not be realized on a conventional plant layout CAD system. The major function of the system is the automatic constraint checking of each designer’s drafting action. This function is achieved by the integration of a geometric modeler, frame representation, and production rules. The geometric modeler is used for extracting the information for data updating and constraint checking from graphical objects, which are directly manipulated by a designer. Frame representation is used for representing the attributes of the equipments and the areas, and these attributes are handled by production rules. Production rules are used for representing the constraint checking and data updating procedures, and can be executed as required.

Constraint Absorption and Relaxation Using a Design History

A simple mechanism has been implemented and demonstrated within a routine design expert system. It has a limited ability to adjust design constraints based on experience within the domain. The mechanism is activated in response to noticing an extended run of either constraint failures or constraint successes. It reasons about the validity of either relaxing or absorbing a constraint. This process is referred to as Constraint Absorption. We hope to improve the performance of the expert system by reducing the incidence of repeated constraint failure, and by eliminating redundant constraints.