The Information Axiom and Robust Design

In preceding chapters, it was emphasized that the first task in innovative design is the problem definition. The problem is then transformed into functional requirements (FRs), then into design parameters (DPs) and process variables (PVs), the vectors that define the four domains of the design world. Design matrices give the relationship between these vectors. The Independence Axiom states that the FRs must always be independent of other FRs as DPs and PVs are chosen. In this chapter, the role of the Information axiom in creating the best design is presented, including how to measure the information content, how to make a design robust by satisfying the Independence Axiom and the Information Axiom. A coupled design has large information content, in some cases, approaching infinite information content, which implies that the design will never work as intended. An uncoupled design can be made to have zero information content, making the design easy to implement and the resulting design most reliable. The determination of information content is presented in this chapter with many examples.