Observers for multivariable systems with inaccessible inputs

A theory of observers for discrete-time linear systems with inaccessible inputs is developed utilizing a dynamical inverse/state observer structure. It is shown that without any assumption on the form of the inputs, an observer can be designed that asymptotically will track the state for a certain class of systems. Furthermore, a considerable saving in input sensors (hardware) can be accomplished by using software to implement the dynamical inverse. An illustrative example and recommendations for future research are included.