Performance recovery of a discrete-time MIMO nonlinear system using a fast observer

This paper presents a multi-rate digital control scheme for a class of nonlinear systems where the controller and observer are both designed in discrete time and where the plant has zero dynamics and is multiple input, multiple output (MIMO). The fast observer is a discrete time analogue to the high gain observer, which can achieve quick estimation of states. Performance recovery is achieved with the fast observer and control saturation.