Comparison of Optimal Linear Regulators Applied to Minimization of Steering Losses of a Containership in a Seaway Using Frequency Domain Representations

Abstract

Linear Quadratic Gaussian (LQG) techniques are applied to the design of a steering controller for minimization of propulsion losses due to steering of a high-speed containership in a seaway. Alternate performance criteria are used deriving from the evaluation of the nonlinear force derivatives of the surge equation related to steering. The sensitivities of the various resulting LQG controllers to the seaway environment are compared using frequency domain representations of the seaway disturbances which are shown to be far from white Gaussian noise. The implications for optimal linear regulator design in this environment are discussed on the basis of the results presented.