Control Lyapunov Functions and Stabilization by Means of Continuous Time-Varying Feedback

For a general time-varying system, we prove that existence of an "Output Robust Control Lyapunov Function" implies existence of continuous time-varying feedback stabilizer, which guarantees output asymptotic stability with respect to the resulting closed-loop system. The main results of the present work constitute generalizations of a well-known result towards feedback stabilization due to J. M. Coron and L. Rosier concerning stabilization of autonomous systems by means of time-varying periodic feedback.Comment: Submitted for possible publication to ESAIM Control, Optimisation and Calculus of Variation

Further Remarks on the Sampled-Data Feedback Stabilization Problem

The paper deals with the problem of the sampled data feedback stabilization for autonomous nonlinear systems. The corresponding results extend those obtained in earlier works by the same authors. The sufficient conditions we establish are based on the existence of discontinuous control Lyapunov functions and the corresponding results are applicable to a class of nonlinear affine in the control systems.Comment: 6 page

Observability and State Estimation for a Class of Nonlinear Systems

International audienceWe derive sufficient conditions for the solvability of the state estimation problem for a class of nonlinear control time-varying systems which includes those, whose dynamics have triangular structure. The state estimation is exhibited by means of a sequence of functionals approximating the unknown state of the system on a given bounded time interval. More assumptions guarantee solvability of the state estimation problem by means of a hybrid observer