Stability of autopiloted ships in a following sea.
Folsom, David Lindley.
Mandel, Phillip A.
MetadataShow full item record
The object of this thesis was to investigate the stability of a ship with automatic steering in a following sea using the nonlinear equations of motion and to compare these results with the results of linear approximations. The solution of the nonlinear equations was obtained by a technique of treating nonlinear terms as linear terms with non-constant coefficients. Results showed that when drift angles become 0.1 radians or greater the nonlinear solution differs substantially from the linear solution. But the nonlinear solution has a greater range of stability in the wave profile than the linear solution. This leads to the conclusion than a system designed using linear theory provides sufficient stability for the ship in a following sea. The most important effect which this approach neglected was the coupling effect of the roll or heel motion on the yaw motion. Before a complete and accurate solution to the steering problem can be found the coupling effect must be investigated and some method of expressing it analytically must be produced.
This thesis document was issued under the authority of another institution, not NPS. At the time it was written, a copy was added to the NPS Library collection for reasons not now known. It has been included in the digital archive for its historical value to NPS. Not believed to be a CIVINS (Civilian Institutions) title.
Showing items related by title, author, creator and subject.
Detumbling and nutation canceling maneuvers with complete analytic reduction for axially symmetric spacecraft Romano, Marcello (2010);A new method is introduced to control and analyze the rotational motion of anaxially symmetric rigid-body spacecraft. In particular, this motion is seen as the combination of the rotation of a virtual sphere with respect ...
Korkut, Murat (Monterey California. Naval Postgraduate School, 2002-12);The goal of this study is to investigate the nonlinear dynamics of two ships in close proximity towing. The sway and yaw dynamics of both the leading and the trailing ships were included in the formulation. Previous studies ...
McLeod, Christopher W. (Monterey, California: Naval Postgraduate School, 2013-09);This thesis will examine the effect of nonlinearities on the propagation of orbit uncertainties in order to gain insight into the accurateness of the estimation of covariance with time. Many real-world applications rely ...