DIRECT DRIVE VOLUME CONTROL OF HYDRAULIC SYSTEM AND ITS APPLICATION TO THE SHIP

Direct Drive Volume Control Hydraulic Servo System (DDV System) is the system which can control the position of actuator with controlling the revolution of hydraulic pump directly.This system is known that it can decrease energy consumption because the pump is driven only when the motion of actuator is required. It does not has a transient phenomena such as surging because the change of actuator motion is carried out with changing the direction of pump revolution. It can make the size of system very small, because heat loss of the system is small and it does not require a large size of oil tank for cooling. Many kinds of hydraulic system are used in a ship. One of the most important system is steering system and we adopted the DDV system to “Shioji-maru” which is the training ship of Tokyo Univ. of Mercantile Marine. The results of this study was excellent ; the size of hydraulic source system become less than 1/10, energy consumption become under 1/20 and surging is eliminated.Considering those results, the authors are trying to apply this system to anti-rolling system with rudder or fin stabilizer.