Performance effects of optimal LQG eigenvalue placement in ship control

The eigenvalues of a linear time-invariant system may be optimally placed by using performance criterion modification in the optimal controller design. This is approach is applied to the design of a linear quadratic Gaussian controller for a submarine. The results are compared to a linear quadratic Gaussian controller designed by standard loop-shaping methods in the state estimator design and using a linear quadratic regulator to perform loop transfer recovery. Improvements in performance can be obtained after applying loop transfer recovery by assigning the eigenvalues of the optimal state feedback system to desired locations.