Cascade Observer Design Method for Systems with Uncertainty

The asymptotic observer design problem is considered for a system with uncertainty (i.e., with an unknown bounded input) and with arbitrary relative order. If the zero dynamics is stable, then part of the state vector can be reconstructed asymptotically exactly, but so far there has not been an exhausting asymptotic observer design method for the part of the state vector formed by the derivatives of the measured output. We propose such a method for a system of second relative order and generalize the result to systems of arbitrary relative order.