Modeling of linear time-varying systems by linear time-invariant systems of lower order
Hamed Nosrati, H. E. Meadows · IEEE Transactions on Automatic Control · 1973
A technique for modeling linear time-varying differential systems by linear time-invariant systems of lower order is discussed and criteria for determining stability, uniqueness, and the choice of the model of a given dimension are developed. In addition, a lower bound for the minimized performance index is derived and the effect on it of decreasing the dimension of the model is demonstrated.