Exploring Partitioning in Subsystem Prototyping

The development of a novel complex system is often cost-prohibitive. One reason for this, is that system-level performance can typically only be evaluated once all subsystems have been designed; and therefore, it is difficult to iterate on full system prototypes. Subsystem isolation is a well-established prototyping method to enable efficient design at both the system and subsystem levels. In this process, a complex system is partitioned into manageable subsystems that are subsequently designed in detail. Subsystem isolation permits rapid, low-cost iteration which is known as a critical driver of prototype performance. This paper provides an exploration of the role of partitioning in subsystem isolation prototyping through a review of methods and an applied case study. The paper reviews two topics related to subsystem isolation prototyping: 1) partitioning approaches and 2) strategies for iteration at the system versus subsystem level. Methods from design theory, systems engineering, and multi-domain optimization are reported. The case study explored subsystem prototyping in the design and construction of an electric in space propulsion test facility utilized in DoD research. The case study is used to demonstrate the processes involved in system partitioning methods and subsystem level design. These approaches allow designers to efficiently explore options for architecture-level design, without expending unnecessary resources on iterations of the integrated system.