Robust Control For Nonlinear Uncertain Systems

In this paper, we consider nonlinear feedback controller design and disturbance atten-uation problem of continuous time finite-dimensional uncertain systems, where the uncer-tainties mainly come from the unknown continuous parameters, time-varying disturbance and uncertain nonlinearities.The paper consists of four chapters.Firstly, we introduce some related development situation and research background.Secondly, focused on the class of uncontrollable planar systems, we research the prob-lem of smooth output feedback stabilization. Based on the Backstepping method and modified power integrator approach, construsts a nonlinear-gain observer and smooth out-put feedback controller, which ensures that the closed-loop system is globally asymtotically stable. The example illustrats the result of this section.Furthemore, this section shows that under an appropriate input-to-state stability con-dition, resulting in globally adaptive stabilization and smooth partial-stste feedback control laws for cascade systems. This conclusion is proved by the small gain theorem and the parameter separation technique combined with feedback domination design.Finally, this section deals with the robust adaptive disturbance attenuation for uncer-tain nonlinearly parameterized systems. Based on Lyapunov stability theory and modified power integrator approach, the adaptive controller is designed to ensure the states of the closed-loop systems globally asymptotic stabilization.