Coupling in design and robust control optimization

System performance can significantly benefit from optimally integrating the design and control of engineering systems. As part of an effort to improve the robustness properties of systems, the present article introduces a general approach that combines design with robust control and investigates the properties of coupling between them. This integrated design and robust control approach leads to a coupled optimization problem that is often difficult to solve. This article introduces an explicit measure of coupling between the design and robust control optimization problems. The effect of parameters (i.e., level of uncertainty, objective weights, design and control model parameters) on this coupling is then studied. Varying such parameters leads to establishing a relationship between coupling and robustness of the control system. This link between coupling and robustness can be utilized to aid the designer in assessing the parameters' influence on coupling and robustness. Results show that the coupling strength between design and robust control tends to increase as the applied level of uncertainty increases.