H-INFINITY MU CONTROL-BASED FREQUENCY-SHAPED SLIDING MODE CONTROL FORFLEXIBLE STRUCTURES/

In this paper we propose a new sliding mode control method using H-inf inity/mu synthesis theory. This concept is based on the frequency-shap ed approach. A conventional hyperplane consists of a desired reference model without dynamics. Therefore, the sliding mode control system of ten becomes unstable based on spillover phenomena in a high-frequency region. On the other hand, the proposed design method can completely s uppress such spillover phenomena because of the frequency-shaped hyper plane. Also, the controller designed by the proposed method has not on ly stability robustness but also robust performance in cases of parame ter variations in the hyperplane to minimize the maximum singular valu e and structured singular value from some noise to the controlled vari ables. We have applied this new method to a flexible structure of a mi niature test rig with four stories. We have verified from simulations that the new sliding mode control method proposed by us exhibits good performance and is very useful for suppressing the spillover in a high -frequency region.