Analysis of robust asymptotic tracking performance for a class of uncertain plants with triangular structure

In the design of servo systems, it is desired to use as few servomechanisms as possible. So it is necessary to find the necessary and sufficient condition for given servo problems. Particularly we are interested in servo problems of uncertain plants. In this paper we deal with the robust tracking problem of a class of uncertain plants with triangular structure. To reduce unnecessary servomechanisms, a decentralized control scheme is adopted and the necessary and sufficient condition of robust tracking is derived. Further, this condition is converted to a μ condition, thus enabling its synthesis with well-known tools