The evaluation and reduction of complexity in position-dependent interactions in machines of significant complexity

In complex machines there are many functional interactions that depend on precise relative positions of functional elements, surfaces, subassemblies, and modules. Consequently, it is of utmost importance that the configuration of a complex machine be capable of satisfying the positional requirements of the various interacting elements. Traditionally, because of tight product schedules and the need to proceed to detailed design, only a limited amount of time is accorded this very important phase of the product development cycle. However, once the configuration of a complex machine is specified, it is only with great penalty that significant changes are made to the configuration. The research effort documented in this dissertation addresses the design of configurations of complex machines. In particular, issues related to achieving the relative positions of critical functional elements in a complex machine are treated by way of evaluation tools and examples for structured configuration design. These evaluation tools have been developed to enhance the configuration design process by providing information needed to develop superior configurations early in the product development schedule. Three methods have been developed for the purpose of evaluating the configuration of complex machines: (1) The Map of Connections, (2) Connection Complexity Evaluation, and (3) Complexity Factor Evaluation. In all cases, the metric for comparing configurations is relative complexity. The evaluation methods focus on the major contributors to complexity in the mounting schemes used in positioning functional elements relative to one another. Complexity is defined as the level of difficulty associated with securing functional elements relative to one another. It is expected that the evaluation methods developed through this research effort will be used at the configuration design phase to iteratively select the least complex configuration that meets the requirements of functional elements and surfaces with position-dependent relationships. By providing a common language for use in the area of relative element placement in configuration design, the evaluation methods presented in this dissertation are expected to facilitate configuration description, discussions, and evaluation.