A new design of extended state observer for a class of uncertain nonlinear systems with sampled-data measurement

To expand the application of extended state observer (ESO) to nonlinear uncertain hybrid systems, the paper proposes a new design of ESO based on sampled-data measurement. To theoretically show the effectiveness of the proposed hybrid ESO, both the stability and convergence of the ESO are investigated. More specifically, the dynamics of the estimating error and the corresponding equilibrium set are analyzed, which provides a mathematical technique to deal with the jumps in hybrid systems. Based on the properties of the equilibrium set of error dynamics, we then prove the stability and convergence of the proposed ESO. More importantly, owing to the explicit stability condition, the tuning law of the observer gain vector is illuminated.