A tuning algorithm for multivariable restricted structure control systems using subspace identification

This paper presents a new method to design a restricted structure controller driving a multivariable plant using subspace identification methods. The algorithm employs data collected from closed-loop operation to identify an open-loop model of the plant using subspace identification. The method also requires knowledge of the first N impulse responses from the controller. The multivariable controller parameters are calculated by minimising a finite horizon LQG criterion subject to nonlinear constraints. Three simulation case studies are presented.