Gain scheduling using the Youla parameterization

Gain scheduling controllers are considered in this paper. The gain scheduling problem where the scheduling parameter vector /spl theta/ cannot be measured directly, but needs to be estimated, is considered. An estimation of /spl theta/ has been derived by using the Youla parametrization. The use of the Youla parameterization in connection with the estimation of /spl theta/ gives a direct validation method for the estimate of /spl theta/. The validation is an integrated part of the estimation method. This makes it possible to estimate /spl theta/ very precisely. This is important in connection with /spl Hscr//sub /spl infin// gain scheduling controllers.