Designing Transitions in Multi-Region Devices

Generative, model-based design of physical devices with multiple operating regions poses challenging problems . We present an approach for establishing region transitions of multi-operating region devices based on an analysis of the more basic shifts of the qualitative regions of quantities and their synchronization . The method takes as input design fragments, constructed by model-based design methods, which establish desired qualitative behaviors specific to a region . A design fragment is an intermediate representation that makes explicit the causal relation network and the operating assumptions under which the qualitative behavior in a region is established . The method identifies the quantity shifts to be established and the synchronization constraints that must be satisfied by the design fragment for a region if the device is to transition to the adjacent region . It revises the design fragment and the initial design to establish such shifts. We present the theoretical basis of the method, and show how the method may be used for the conceptual design of a steam engine .