Robust Bode controller design methods for unstable and non-minimum phase systems

In this paper, we extend Robust Bode loop-shaping design methods to open-loop unstable and non-minimum phase SISO systems.We show how loop-shaping controller design may be performed using either the Contoured Robust Controller Bode (CRCBode) plots or a new Robust Bode plot based on the Youla parametrization of all stabilizing controllers (QBode). We demonstrate the effectiveness of these approaches by designing robust stabilizing controllers for the linearized dynamics of an inverted pendulum system which is both open-loop unstable and non-minimum phase.