On Time Moments and Markov Parameters of Continuous Interval Systems

In this paper, two expressions are derived for calculating the time moments and Markov parameters of continuous interval systems. The expressions presented are computationally simple and do not require inversion of denominator of the system transfer function unlike other techniques. The usefulness of expressions derived is shown with the help of Routh–Pade approximation of interval systems. The derived Routh–Pade approximants retain not only the time moments but also some Markov parameters of high-order interval system. Some improvement is also found in system approximation when these time moments/Markov parameters are used. One numerical example is included to illustrate the effectiveness and simplicity of proposed method.