The Study On Modeling And Control Of Anti-swing Mechanism For Marine Davit

The marine davit of rigid connections is an important device used for releasing and recycling small boat under sea waves,which is similar to marine crane. While the davit releases or recoveries the small boat, the swing motion of the mother ship induced by sea wave can cause motion of hanging point of the davit, which will induce sharp swing of the small boat hanged on the arm of the davit. The sharp swing of the boat is very dangeous, it is not only may cause the damage of the boat and related equipments, but also induce casualties. Therefore, it has important significance to study the swing mechanism of the small boat in the process of releasing and recovering under sea waves, and to study anti-swing control technology.In this paper, Basing on relate references both here and abroad, the dynamic motion transitive relation between the mother ship and end of the arm is analyzed deeply by using coordinate transformation method. After that, the motion transfer model between mother ship and handing point of the davit is established according to the positive and reverse kinematic principles. And then, the dynamic model of the davit is established with the Lagrange equation, in which, the disturbed force caused by motion of arm handing point is regarded as its input. After analysis factors influencing swing of small boat, the simulation model is established and siumation is done, from simulation result, main factors affecting the swing of the small boat are concluded.Finally, basing on the anti-swing theory of rigid connective davit and model of actuator,by using neural cell net, an anti-swing controller is designed, in which the anti-swing compensation of the hydraulic cylinder is regarded as its driving unit, and the actualmovement value of the hydraulic cylinder as its output. After its stability is analyzed, and then the simulation on the anti-swing control system based on neural networks is done. In comparing with traditional pid controllor ,the results show that the controller can effectively reduce the swing of the small boat.