This work focuses on the mathematical modeling and simulation of an elastic ship-mounted crane with Maryland Rigging. Such a crane is usually used to transfer cargo from one ship to another in an open sea. During the transfer process wave-induced motions of the crane can produce large oscillations of the cargo being hoisted which endanger the operation of the crane and force the cargo transfer to be suspended. This paper deals with development and simulation of the nonlinear model of the ship-mounted crane. 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 loner 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 he 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.
Modeling and simulation of an elastic ship-mounted crane
Modell und Simulation eines elastischen Schiffkrans
2005
11 Seiten, 12 Bilder, 8 Quellen
Conference paper
English