Working area of the helicopter PAD stabilization mechanism

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 four independent cable 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 and transverse axis and the displacement of the deck along the transverse and vertical axis within the limits of the work area. The mechanism consists of four movable links on which the movable helicopter pad platform is located. As the linear actuators, trolleys moving along horizontal guides were used, powered by system of steel cables with four independent electric motors. In folded state the mechanism, take up appropriately little space under 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 speeds. For the adopted assumptions simulation was performed, confirming the predicted behaviour of the system. Based on the kinematic equations of system and taking in consideration collisions and geometrical limits, working area for the flat part of the mechanism was determined.