Linear system reduction by impulse energy approximation
A method is given for linear system reduction which is a more general form of the Routh method. The reduced models retain stability, and a fuller contribution is made to the impulse response energy of the reduced system by appropriate selection of retained alpha and beta parameters. It requires no more computation than the Routh method and can be presented in a compact tabular form. Examples are given to illustrate the method.
Lucas, T.N. 1985. Linear system reduction by impulse energy approximation. IEEE Transactions on Automatic Control. 30(8): pp.784-786. Available from http://dx.doi.org/10.1109/TAC.1985.1104063