Linear quadratic regulator loop shaping for high frequency compensation

This paper establishes a design technique that incorporates high-frequency design specifications into the framework of the LQG/LTR technique. This is accomplished by augmenting plant input with extra dynamics. Singular perturbation techniques are used to select input weighting functions for the LQR design. The change in nominal design due to the plant input augmentation is quantified. An estimate of the change of the loop transfer function in the performance region is also determined