A robust controller interpolation design technique

Switching or blending among controllers is termed controller interpolation. This paper investigates a robust controller interpolation technique and applies it to an experimental test bed. Although an interpolated controller is composed of linear timeinvariant (LTI) controllers stabilizing the LTI plant, closed-loop performance and stability are not guaranteed. Thus, it is of interest to design the interpolated controller to guarantee closedloop stability and a performance level for all interpolation signals describing controller switching sequences and combinations. The performance metric that is under investigation in this paper is the H_∞ norm. A suboptimal robust interpolated-controller design algorithm is framed in terms of bilinear matrix inequalities. The motivating example demonstrates the efficacy of the robust interpolated- controller design.