Controller synthesis of optimal sensitivity: multivariable case

In the paper the synthesis of optimal controllers for the minimum H∞ and H2 norm of the weighted sensitivity function is extended to a multivariable system. Two direct algorithms are introduced to synthesise the optimal controllers to minimise the H2 and H∞ norm of the weighted sensitivity matrix in a multivariable system. A fractional representation approach and the Wiener Hopf variational technique are employed to treat these minimum-norm problems.