Robust optimal digital control synthesis using parameter optimization

This paper presents a direct synthesis of optimal robust low-order digital controllers using a design procedure called extended optimal W-synthesis (EOW). This method enhances the digital design method developed earlier for dynamic and static output feedback designs, allowing designers to select a controller of a pre-specified order and structure. Furthermore, a multi-objective function is formulated to address design robustness to parameter variations. A set of necessary conditions for optimality have been developed and used in the numerical solutions of the optimum design. The algorithm is applied to the synthesis of a robust control law for a flexible two-link robot arm