Collaborative optimization - Status and directions

This paper describes the current status of research on collaborative optimization, a strategy for distributed design, and its application to large-scale aerospace systems. This approach to computation-based design provides a method by which design tasks may be decomposed into domain-specific subproblems, and coordinated to achieve an optimal system. Developed over the past few years by researchers at Stanford, NASA, Boeing, and other universities, the methodology is now being applied to large-scale problems requiring high-fidelity modeling. The paper describes some of these applications, summarizes recent results, and suggests variants of collaborative optimization that have been found to improve overall performance. Introduction and Background Most applications of multidisciplinary optimization initially involved the direct integration of multiple disciplinary analyses and an optimizer. For small problems, wiring together such a system is quite feasible and leads to a usually efficient, but often hard to explain, procedure. As computational capabilities grew, engineers scaled this approach to larger problems and its limitations became apparent. The need for analysis and data management became better recognized and a second generation of MDO methods came into use. Distributed analysis systems could utilize multiple computers, increasing the practical scale of MDO problems. Database management and modular analysis coordination improved efficiency and maintainability. Despite these improvements, the reliance on a central optimizer as decision maker on all matters, is not a practical approach to large-scale system design. This deficiency has led to the development of what may be considered the third generation of MDO methods: strategies for distributed design optimization. These three types of MDO systems are illustrated in figure 1. Design Subtask Optimization Coordination DBMS Design Subtask Design Subtask Design Subtask Analysis Optimization Coordination DBMS Analysis Analysis Opt. ptimizer 1