Engineering Reasoning in Set-Based Design

Set-based design (SBD) is derived from a Toyota Motor Corporation approach now being applied in other more general engineering design processes. Engineering design processes can be described and classified in terms of the types of reasoning used. The three basic reasoning approaches are inductive, deductive, and abductive. Engineering design has also been described in terms of a composite class called retroductive reasoning. The difference between the reasoning approaches is in what is initially given and what is generated during the application of the process. The paper defines the engineering reasoning behind SBD. Our approach is to present various traditional engineering design processes in terms of engineering reasoning classes, and to create a definition of the SBD reasoning approach. The approaches are described in the context of decomposition-based design processes typically applied to systems to understand where the specific differences are between SBD and conventional design methods. In so identifying these differences, this paper provides a basis to help formulate the approach used in SBD. The resulting description of the reasoning needed for SBD will assist engineers in formulating future applications more consistently.