Yaw/Roll Control Design for High-Speed Containerships

摘要

The anomalous behavior, and the robust, multivariable, nonminimum phase and nonlinear control issues, related to course-keeping autopilot design which account for dynamic yaw/sway/roll/rudder coupling effects and steering system nonlinearities in high-speed containership operation are investigated. The causes of the problem are explained through development of appropriate dynamic models, analysis techniques and computer nonlinear simulations. A control system methodology to alleviate the problem is presented. On the basis of the results obtained, active rudder roll stabilization, i.e. roll stabilization by means of the rudder, is found to be infeasible for the ship type examined. The robust control design methodology derived is shown, however, to permit the design of autopilots which will improve the stability of the controlled ship and reduce operating costs resulting from propulsion losses associated with the problem.