Target cascading in optimal system design.

Target cascading is a key challenge in the early product development stages of large complex artifacts: How to propagate the desirable top level design specifications (or targets) to appropriate specifications for the various subsystems and components in a consistent and efficient manner. Consistency means that all parts of the designed system should end up working well together, while efficiency means that the product development process itself should avoid iterations at later stages, which are costly in time and resources. In this dissertation target cascading is formalized in a process modeled as a multilevel optimal design problem. Design targets are cascaded down to lower levels using partitioning of the original problem into a hierarchical set of subproblems. For each design problem at a given level, an optimization problem is formulated to minimize deviations from the propagated targets and thus achieve intersystem compatibility. Target cascading (TC) can be reformulated as a hierarchical overlapping coordination (HOC) algorithm possessing a non-ascent property. The equivalence between the TC and the HOC formulations, i.e., both decomposed problems possessing the same objective and constraint sets provides a theoretical foundation for asserting that the TC algorithm will reach the target deviations. The target cascading process is illustrated in a case study involving a ground vehicle chassis design problem. The target cascading process implementation in an actual organization is also presented along with sample model forms for collecting and assembling the requisite analysis models.Ph.D.Applied SciencesMechanical engineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/125689/2/3016884.pd