LQG adaptive autopilot design

Three approaches to autopilot design for ships are proposed and discussed. Some of the difficulties in providing adequate course-keeping performance by conventional control are overcome by the development of an explicit adaptive LQG design. The new scheme has several interesting features. An output wave model is adopted so that only low frequency heading deviations are minimised. A dynamic cost function weighting is introduced to enable the added resistance due to steering to be minimised. The polynomial systems approach to linear quadratic control provides a neat solution to the optimal control problem. The proposed autopilot has been used in a simulation trial to demonstrate the improvements that can be attained in the disturbance rejection properties