Introduction to quantitative engineering design methods via controls engineering

Abstract

Functional modeling is an effective method of depicting products in the design process. Using this approach, product architecture, concept generation, and physical modeling all contribute to the design process to generate a result full of quality and functionality. The functional basis approach provides taxonomy of uniform vocabulary to produce function structures with consistent functions (verbs) and flows (nouns). Material and energy flows dominate function structures in the mechanical engineering domain with only a small percentage including signal flows. Research suggests that the signal flow gap is due to the requirement of “carrier” flows of either material or energy to transport the signals between functions. This research suggests that incorporating controls engineering methodologies may increase the number of signal flows in function structures. We show correlations between the functional modeling and controls engineering in four facets: schematic similarities, performance matching through flows, mathematical function creation using bond graphs, and isomorphic matching of the aforementioned characteristics allows for analogical solutions. Controls systems use block diagrams to represent the sequential steps of the system. These block diagrams parallel the function structures of engineering design. Performance metrics between the two domains can be complimentary when decomposed down to nondimensional engineering units. Mathematical functions of the actions in controls systems can resemble the functional basis functions with bond graphs by identifying characteristic behavior of the functions on the flows. Isomorphic matching, using the schematic diagrams, produces analogies based upon similar functionality and target performance metrics. These four similarities bridge the mechanical and electrical domains via the controls domain. We provide concepts and contextualization for the methodology using domain-agnostic examples. We conclude with suggestion of pathways forward for this preliminary research.

Function modeling using the system state flow diagram

“…Triengo and Bos (1985) note that it is difficult to model mechanical systems, while Umeda et al (1990) pointed out that the model focuses on structure and behavior of a system, but not on its functions. Recent work has focused on addressing this shortcoming, as evidenced by Lucero et al (2017) and Mokhtarian et al (2017), who both tabulate mappings of the five bond graph elements to the functional taxonomy of Stone and Wood (2000).…”

Thoughts on benchmarking of function modeling: Why and how

“…In another offering, “Introduction to Quantitative Engineering Design Methods Via Controls Engineering,” Briana M. Lucero, Matthew J. Adams, and Cameron J. Turner first observe that function models of electromechanical products commonly practiced and taught in design education, such as those stored in the Oregon State Design Repository, do not include satisfactory modeling protocol for signal flows, despite signal being one of the three major flow types in function literature alongside material and energy (Lucero et al, 2017). The authors suspect that this gap could be the result of a lack of formalism for modeling signals as nonconserved flows that are carried by material or energy flows.…”