A dynamic high gain observer for a class of MIMO non triangular systems

Abstract A dynamic high gain like observer is proposed for a class of MIMO nonlinear systems that are observable for any inputs. Two main results are worth to be mentioned. The first one is related to the considered class of systems that is composed by cascade subsystems and each subsystem is associated to a subset of the outputs. Each subsystem assumes a triangular dependence on the state of that subsystem itself but may depend on the state of all other subsystems. Hence, the contribution is to extend the results existing in the literature in that more interconnections between the subsystems are allowed. The second important result lies in the nature of the observer gain which involves a scalar time-varying parameter governed by some scalar Riccati equation. Simulation results are given in order to highlight the performances of the proposed observer, namely its exponential convergence and a good behavior with respect to noise measurements.