Abstract |
- An information processing model of the problem-solving
performance of mechanical designers is presented for four design
tasks: conceptual assembly design, layout component design, detail
component design, and catalog selection. These tasks are organized
into six kinds of segments called episodes, which describe the goal
structure of the designer while performing the task. The episodes
are identified as plan, assimilation, specification, verification,
repair, and documentation. The basic building blocks that designers
apply during these episodes are known as operators, of which ten have
been identified: select, create, simulate, compare, calculate,
accept, reject, suspend, refine, and patch. These operators are
applied in groups which comprise four local methods, identified as
generate-and-test, generate-and-improve, deductive thinking, and
means -end-analysis. These operators applied according to these
methods constitute local design performance. Identifying these
processes isolates which functions need to be performed by
intelligent computer-aided design tools for assisting mechanical
designers. Observations of global design performance, independent of task
type, are also presented under nine topics. For example, designers
often pursue a single conceptual design, and designers find
satisfactory rather than optimal solutions to design problems. These
observations provide insight as to the flexibility and level of
intelligence actually needed of CAD tools as well as establishing
differences between observed design performance and present design
methodologies.
A comparison of this research to other studies in mechanical
design is also presented to solidify what is known or not known about
mechanical design. This information has never previously been
assimilated into coordinated and specific statements.
These descriptions of the mechanical design process are based
on the case studies of five mechanical designers, gathered through
verbal protocol techniques of cognitive psychology. A data
management technique called breakdown analysis was applied to over 36
hours of protocol data to identify the tasks, episodes, and operators
that describe the process of mechanical-design performance.
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