Traditionally, the design of structural systems and vehicles has focused first on the design of the structure and then the control and other aspects are considered. But systems of the future will be evaluated based on closed-loop metrics and will be designed directly for ‘high-performance’ applications. Such capability depends on a synergistic integration of different disciplines and sub-systems, which cannot be captured by the traditional sequential design approach. Hence, it is imperative that a formulation for design be introduced that inherently considers the interactions between different disciplines and brings in controls earlier in the design process for optimal closed-loop performance. But existing approaches to the simultaneous design and optimization of the dynamics and the controller have some issues for realistic systems. This dissertation introduces an approach that overcomes some of the drawbacks of the existing simultaneous design approaches.

This research introduces a formulation for multi-disciplinary design optimization with an emphasis on control. This approach notes that since mission capability is evaluated using a closed-loop configuration; the design must consider closed-loop performance when choosing system parameters. The approach does not actually optimize both the open-loop plant and controller simultaneously; rather, the approach minimizes a closed-loop norm by optimizing over the open-loop plant while constrained to satisfying conditions for controller existence. In this way, the approach finds the optimal plant along with the open-loop variables for which a controller exists such that the closed-loop system is optimal. This approach is developed for H_∞, H₂ and linear parameter varying (LPV) control synthesis techniques. Surrogate-based design optimization with multiple surrogates is used to find the optimal configuration of the design variables.

The proposed approach is investigated for vibration attenuation of a hypersonic vehicle. Structural damage resulting from the tremendous heating incurred during hypersonic flight is mitigated by a thermal protection system; however, such mitigation is accompanied by an increase in weight that can be prohibitive. The actual design of a thermal protection system can be chosen to vary the level of heating reduction, and associated weight, across the structure. This research considers how such designs and resulting thermal gradients influence the ability to achieve closed-loop performance. The proposed control-oriented design approach answers the question on how to design the thermal protection system for the optimal thermal profile for which a controller exists and optimizes closed-loop performance.