MODELING AND SIMULATION OF AN ELASTIC SHIP-MOUNTED CRANE

摘要

This paper deals with development and simulation of the nonlinear model of an elastic ship-mounted crane equipped with the Maryland Rigging. The model contains three inputs to control the planar vibrations due to the planar base excitation; the luff angle is proposed to control the elastic vibration in the boom, and the length of the upper cable in conjunction with the position of its lower suspension point are proposed to control the pendulation of the payload. It is observed, through static and dynamic testing of the derived model, that moving the lower suspension point of the upper cable provides strong controllability of the horizontal displacement of the payload, while changing the length of the cable can be employed to compensate for the vertical displacement. Simulation results show that within a considerable range of pendulation displacements of the payload, the nonlinear model and the linearized one reflect nearly equivalent responses. Hence, with the property of strong controllability, the linear model can be used efficiently to design the control system, which will be discussed later in another paper.