Discrete-Time Observer Design for a Class of Nonlinear Systems Including Newtonian Mechanical models: Application to an Autonomous Four Rotors Helicopter

In This paper we consider the state estimation problem for a class of Euler discretized nonlinear systems generalizing the Newtonian mechanical systems with position measurements. The proposed observer (software sensor) is based on the pole placement technique used for linear systems, which the gain matrix of the observer is a time varying. Finally we apply the observer design to a four rotors helicopter to estimate the linear and angular velocities and we present simulation results to demonstrate the convergence of the state estimates to their true values and to illustrate the performance and robustness of the proposed estimator when the measured positions are noisy