A Constraint Based Model of the Design Process: Complexity, Uncertainty, and Change.

摘要

Products, users, cultures, and designers all interact in complex, non-linear ways, as designers, users, and organizations each attempt to meet their own unique goals. The design and performance of today's products are influenced by technological change, mechanical design, design for manufacture, human factors, psychology, anthropology, legal concerns, regulations, and market pressures. As a result, product design is inherently multidisciplinary, and there is a need to balance a complex set of factors that characterizes the product's performance. Additionally, in a truly complex environment, designs are not static. Trade-offs, uncertainty, and change typify most physical products, as designs shift and grow alongside users, patterns of use, and contexts. In ways strongly reminiscent of coevolution, artifacts shape stakeholders' understandings, tasks, and goals, just as those things shape future designs. This is central to what makes design challenging to do, and to study.;This work serves as an introduction to complex systems, and explains in detail the principles, patterns, and phenomenon that underlie the design and performance of physical artifacts. It attempts to help designers of all types to navigate complexity within the design process, and to manage its effects on artifacts themselves. This was accomplished in three primary ways: an overview of existing complexity literature, the introduction of a constraint framework, and the development of a constraint management tool.;This work present a solid theoretical background grounded in engineering design theory, as well as elements of complex adaptive systems, design constraints, product architecture, and design evolution. It situates products and contemporary product design in the larger field of complex adaptive systems, and shows how CAS theory can be usefully applied to better understand the behavior of products in rapidly changing markets.;Based upon this understanding, a method for rigorously structuring product design problems based on a well--defined set of constraints common to all design--related disciplines is proposed. This constraint framework contributes to design education and practice by providing a scaffold for transdisciplinary instruction and communication with regard to the complexity of product design processes. Finally, this work presents an Excel-based software tool to assist design teams in applying constraints and complexity concepts to design problems. Based on existing matrix modeling methodologies (Design Structure Matrix, House of Quality, etc.), this tool tracks constraint interactions and trade-offs in order to help designers anticipate potential failures, and identify innovative opportunities. This tool was developed and tested in a senior/graduate level course in product design engineering at the Ohio State University. The two conducted studies attempt to assess the impact of the tool on many aspects of the design process including teamwork, design outcomes, creativity, utility, and communication.;When utilized in tandem, the constraint framework and the constraint tool can increase the conceptual and practical accessibility of the complexity that underlies every product design process. If used appropriately, these methods provide a platform for understanding, exploration, and design that can help designers of all types to develop solutions that are better aligned to the constraint environment that characterizes their unique design contexts.