OPTIMAL STOCHASTIC PATH CONTROL OF SURFACE SHIPS IN SHALLOW WATER

The control of a surface ship along a prescribed straight-line path is formulated as a stationary, linear, state-variable control problem. The open-loop characteristics of this problem are studied using data for a Mariner type ship at two speeds and varying water depth-to-draft ratio and for the tanker Tokyo Maru at one speed and varying water depth-to-draft ratio using data obtained by Fujino. Optimal stochastic control systems using a Kalman-Bucy filter and a state-feedback controller are designed for both vessels at various conditions. These designs are developed to control the ship when subject to random, zero-mean disturbances. The design disturbances are the yaw moment and sway force due to a passing ship which are modeled by first-order shaping filters in the design derivation. System performance is studied by the evaluation of the Root Mean Square (RMS) response of the controlled ship to the modeled design disturbances and by digital computer simulation of the response of the controlled ship to initial condition errors and the specific disturbances due to a passing ship. The effects of vessel speed and water depth on the design and performance of these controllers are studied in detail. These results yield guidance for the selection of design conditions for the design of constant-gain controllers and provide an assessment of the need for adaptive controllers which can adjust the gains to remain optimal as the ship characteristics change with vessel speed and water depth.

  • Supplemental Notes:
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  • Corporate Authors:

    University of Michigan, Ann Arbor

    Department of Naval Architects and Marine Engineers
    Ann Arbor, MI  USA  48109
  • Authors:
    • Parsons, M G
    • Cuong, H T
  • Publication Date: 1977-8-15

Media Info

  • Pagination: 88 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00174480
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: ONR-CR215-2492F Final Rpt.
  • Contract Numbers: N00014-76-C-0751
  • Files: TRIS
  • Created Date: Mar 14 1978 12:00AM