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 Ali H. Nayfeh Committee Chair Dean T. Mook Committee Member Scott L. Hendricks Committee Member
Keywords	crane control ship-mounted crane time-delayed feedback
Date of Defense	1999-06-24
Availability	unrestricted
Abstract 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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