Robust Control of a Flexible Arm by H_∞ Control Theory

Abstract

In this paper we apply the robust stabilization problem using normalized coprime factor plant descriptions, which is proposed by Glover et al., to the robust control design for a flexible arm. First we design the feedback controller for this robust stabilization problem, which stabilizes the nominal plant including a rigid body mode and the first two flexible modes. The feedback system with this controller satisfies some design objectives, e. g. the bandwidth requirement. We show that by this controller we can reject the spillover effect of the remaining higher flexibility modes. Furthermore we consider robust stability analysis for the structured uncertainty. We investigate the dependence of the maximum robustness margin on the damping coefficient. Then we calculate a range of the damping coefficient in which stability is guaranteed by the controller which achieves the maximum robustness margin.