Dynamic positioning system of helicopter pad on the ship

Helicopter pad located on the ship significantly increase the operational capabilities of military and civilian ships. During the storm, especially side tilts of the ship hinder or even prevent the safe use of the helicopter pad. It is proposed to apply the system placed between the deck of the ship and landing site plate, driven by three independent linear drives located under the deck. The task of the system will be preventing from transferring to Helicopter pad the tilt of the ship around the longitudinal axis and the displacement of the deck along the transverse and vertical axis within the limits of the work area. The mechanism consists of the three movable pillars with the plate on top, which is the movable helicopter pad platform. As the linear actuators, plates moving along a horizontal guide were used, powered by system of steel cables with three independent electric motors. In folded state the mechanism, take up appropriately little space in the deck area. For the assumed extreme amplitudes of the ship motion, minimum dimensions of the mechanism links that meets the requirement to work in one configuration and lack of collisions were determined. Kinematic relationships were created indicate which mechanical quantities should be measured in real time to determine the momentary drives speed. For the adopted assumptions simulation was performed, confirming the predicted behaviour of the system. Based on the dynamics equations of system, drives loads, their power and individual links and joints load were determined.