A note on robust stabilization and disturbance attenuation

Methods are proposed for designing state feedback or output dynamic feedback controls for linear systems with both parameter uncertainty and exogenous disturbances. Under such control the disturbance effect is reduced to a prespecified level, and at the same time, closed-loop robust stability can be guaranteed. For the case of state feedback, only one Riccati equation is needed to solve the problem. For the output feedback case, the same results are achieved; however, it is necessary to use three Riccati equations, two of which are coupled