Title page for ETD etd-070899-145159

Type of Document Master's Thesis
Author Henry, Ryan J.
URN etd-070899-145159
Title Cargo Pendulation Reduction on Ship-Mounted Cranes
Degree Master of Science
Department Engineering Mechanics
Advisory Committee
Advisor Name Title
Nayfeh, Ali H. Committee Chair
Hendricks, Scott L. Committee Member
Mook, Dean T. Committee Member
  • crane control
  • ship-mounted crane
  • time-delayed feedback
Date of Defense 1999-06-24
Availability unrestricted
It is sometimes necessary to transfer cargo from a large ship to a smaller ship at sea.

Specially designed craneships are used for this task, however the wave-induced motions of

the ship can cause large pendulations of cargo being hoisted by a ship-mounted crane. This

makes cargo transfer in rough seas extremely dangerous and therefore transfer operations

normally cease when sea state 3 is reached. If the cargo pendulations could be reduced in

higher sea states, transfer operations would be possible.

By controlling the boom luff angle, one can reduce the cargo pendulations in the plane of

the boom significantly. A two-dimensional pendulum with a rigid massless cable and massive

point load is used to model the system. A control law using time-delayed position feedback

is developed and the system is simulated on a computer using the full nonlinear equations of

motion. A three-degree-of-freedom ship-motion simulation platform, capable of simulating

heave, pitch, and roll motions, was built. The computer simulation results were

experimentally verified by mounting a 1/24th scale model of a T-ACS crane on the ship-motion

simulation platform.

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