A closed-loop model for general multirate digital control systems

The primary aim of the paper is to develop an adaptable closed-loop model for a general multirate system. This model is an improvement over previous results since it is not restricted exclusively to a multiloop, decoupled, or static compensator environment. However, it is constrained by the requirement that an integral sampling regime must be employed. This constraint, it is felt, is not a consequential disadvantage of the applicability of the model since an integral sampling structure is the natural as well as practical regime to use. The model is adaptable in that it easily accommodates sampling interval changes anywhere in the system. The price one pays for this feature is the high dimensionality that the matrices comprising the model may attain. As is the case in other efforts to characterize multirate systems, the mapping of the continuous compensator and plant models into the discrete domain is the approach used in this paper