Semiglobal L2 disturbance attenuation for a class of SISO nonlinear systems

This paper investigates the problem of semiglobal L₂ disturbance attenuation for a class of nonlinear systems. Our purpose of designing controllers is just to attenuate all disturbances in a given bounded subset of L₂[0, ∞). We prove that for any such a given bounded subset there exist partial state feedbacks and dynamic output feedbacks respectively, which attenuate each disturbance in the given bounded subset in the L₂ gain sense and attain asymptotic stability without disturbance.