Nonlinear reduced order observer design for elastic drive systems using invariant manifolds

This paper presents the design of a nonlinear reduced order observer to estimate the load position and speed of an elastic drive system. The reduced order observer is designed using the notion of invariant manifold. First, a manifold is defined in terms of the error dynamics. Then, the mapping functions are selected in such a way that the error dynamics become asymptotically stable at the equilibrium point. Simulation and experimental results are shown to validate the proposed methodology for a two mass model system.