THE EQUIVALENCE OF MODEL-FOLLOWING SYSTEMS DESIGNED IN THE TIME-DOMAIN AND FREQUENCY-DOMAIN

There are two approaches on the design of optimal model-following syst ems. One is in the time domain (modern synthesis), and the other is in the frequency domain (classical synthesis). In this paper, an equalit y is derived from the expanded Riccati equation. This equality represe nts the relation among the input signal, reference signal, and referen ce model. Together with the return difference equality, the equivalenc e of these two approaches is discussed. Basing on this equivalence, an optimal model-following system can either be designed by the modern s ynthesis approach or the classical synthesis approach. For clarity and simplicity, only single-input/single-output systems are considered. O ne example is used to illustrate the results.