State and input estimation for singular discrete-time systems with unknown inputs

The problem of input decoupled observer design for singular discrete-time systems with unknown inputs was considered. When the system was causal controllable, under the nonsingular transformation, an equivalent problem for discrete-time standard state system was derived. First, an observer of discrete-time standard state system was designed using well-known techniques, and then the input decoupled observer of the singular discrete-time systems was obtained. Finally, the state and unknown input of the singular discrete-time systems are asymptotically estimated using the state of observer and output of systems.