A model reduction strategy preserving disturbance decoupling properties

In this paper, we address the problem of model reduction with control relevant approximation criteria. We focus on a reduction strategy in which the feasibility to design a controller that completely decouples disturbances from to-be-controlled variables in a system is left invariant. The main result of this paper provides a model reduction strategy with the property that disturbance decoupling is possible for the full order system if and only if this is possible for the reduced order system. In addition, controllers that achieve disturbance decoupling for the reduced order system can be implemented on the full order system with guaranteed disturbance decoupling properties