Interval Observers for Estimating Unknown Inputs in Discrete Time-Invariant Dynamic Systems

This paper considers discrete time-invariant systems (with constant parameters) described by dynamic models in the presence of exogenous disturbances. For such systems, the problem of estimating unknown inputs using interval observers is studied. The solution is based on a minimal-dimension disturbance-insensitive model of the original system. For this model, an interval observer is designed and then used to estimate the unknown inputs. The theoretical results are illustrated with a practical example.