Quantitative effects of weight adjustments in ℋ︁ ∞ control

In an ℋ ∞ design, when weights are adjusted, corresponding modifications occur in the synthesized ℋ ∞ controller and the resulting closed‐loop transfer function matrices of interest. In this paper, we seek to understand and provide quantitative results on how weight adjustments directly affect an ℋ ∞ controller and, more importantly, the corresponding closed‐loop transfer function matrices. Here, we explore issues such as whether one can find the new controller as a perturbation of the original controller. Copyright © 2008 John Wiley & Sons, Ltd.