New structures for parameter-insensitive controllers

Several methods have been proposed for designing feedback control laws which are minimally sensitive to variations in system parameters. The restricted structure of these control laws often limits the extent of their parameter insensitivity. In this paper, we show how the state feedback controller form may be extended to allow maximum variations in system parameters without loss of stability or significant deterioration in performance. All control structures are passive and linear. They appear to be most useful when there are large variations in parameter values.