Robust design of non-stationary sinusoidal unknown inputs multiobserver based on decoupled state multimodel

This paper deals with the design of robust non-stationary sinusoidal unknown inputmultiobserver for discrete-time nonlinear systems described by decoupled state multimodel. The particularity of this work resides in the fact that it provides a simultaneous state and non-stationary sinusoidal unknown inputs estimations. A new robust strategy allowing the minimization of the non-stationary sinusoidal unknown inputs and disturbances impact on the state estimation error will be developed.