Complex dynamic system architecture evaluation through a hierarchical synthesis of tools and methods

Abstract

The automobile embodies complex dynamic system architecture with thousands of components and as many interconnections. The modern day vehicle architecture attempts to balance significant tradeoffs and constraints to achieve the system goals. There are innumerable combinations, which may or may not achieve success. This work proposes a new method for evaluation of complex dynamic system architecture through a hierarchical synthesis of specific qualitative and quantitative tools and methods within a system architecture framework. The proposed methodology is applied to key subsystems of a specific high performance car to assess primarily the merits of the process. Current methods for system architecture definition at the automobile manufacturer utilized for analysis rely primarily on experience-based intuition within an architecting framework. Current system architecture frameworks and the manufacturer's process utilized appear insufficient, as significant issues (often dynamics related) arise in the verification and validation phase of their product development process, requiring change to vehicle architecture. Changes in architecture at this phase of the manufacturer's product development process have significant cost, timing and perhaps functional performance implications. Many system architecture and engineering tools exist to aid architecture definition, but a hierarchy in usage and the interrelationships of the tools are not clearly defined. The proposed solution for rigorous complex dynamic system architecture evaluation includes a four phase hierarchical synthesis of known qualitative and quantitative tools and methods within a holistic system architecture framework. For purposes of this thesis, the proposed evaluation methodology is labeled "CD-SAAM" for Complex Dynamic System Architecture Assessment Methodology. The proposed methodology is a rigorous complement, superimposed on the concept development phase, to the standard product development design process. CD-SAAM mainly combines known system architecting and system engineering framework, principles and tools. Application of CD-SAAM to a high performance car's powertrain and chassis system architecture's second level form and function decomposition, serve to demonstrate many high level conclusions. The hierarchy and synthesis of framework, principles and tools in CD-SAAM provided a valuable and rigorous method to evaluate complex dynamic system architecture. While certain aspects of the proposed methodology appear time-consuming, each step and the overall process serve to greatly improve consistent success with respect to achievement of a system's goals within its constraints. Application of CD-SAAM also underscores the importance and need for explicit design parameter identification and analysis in complex dynamic system architecture assessment. The performance car application also provides insight into the value of DOE RSE methods in architecture assessment, as opposed to its typical region of use in detailed design analysis. Finally, a positive by-product of the analysis includes CD-SAAM's ability to evaluate the consistency and attainability of goals within the given constraints.