Unknown inputs observers for a class of non triangular nonlinear systems

In the present paper, we suggest a high gain observer for a class of multi-output nonlinear systems with nonlinearly parameterized unknown inputs. This observer should enable to estimate both the whole state and the unknown inputs, simultaneously. Not only does the gain of the observer not require the resolution of any dynamical system, but it is also explicitly given. For the sake of simplicity, the observer tuning is reduced to the choice of a single design parameter. The paper also reports on the simulation results for the sake of highlighting the performance of the proposed observer.