High gain observer with updated gain for a class of MIMO nonlinear systems

A high gain like observer with an updated gain is proposed for a class of MIMO nonlinear systems that are observable for any inputs. The main contribution of this article lies in the nature of the observer gain that involves a scalar time-varying design parameter governed by some scalar Riccati equation. This time-varying design parameter, chosen constant in standard high observer, allows to get an acceptable tradeoff between state reconstruction speed on the one hand versus amplification of noise on the other. Simulation results are given in order to highlight the performances of the proposed observer, namely its exponential convergence and its good behaviour in dealing with noise measurements.