Sliding-Mode State Observers for a Class of Nonlinear Continuous-Time Systems

The design of full-order sliding-mode state observers for a class of nonlinear dynamic systems is presented. Conditions for the stability of the estimation error in the absence of noises are provided that turn out to be less restrictive with respect to those know up to now for sliding-mode estimators. Such conditions are well-suited to being expressed by using LMIs (linear matrix inequality). If the system is affected by bounded disturbances, it is proved the existence of an attractive invariant set for the estimation error. Numerical results are shown to verify the effectiveness of the proposed approach.