Development of hydraulic gravity canceller with a booster

In this paper, we propose a passive gravity compensation mechanism with two cylinders connected pipeline and a spring element, which named "Hydraulic Gravity Canceller (HGC)." From development and experiments of a single link model equipped with the HGC, it is clarified that this new device has many advantages in comparison with the original "Mechanical Gravity Canceller (MGC)"and other passive gravity compensation mechanisms. First, this paper describes the new mechanism generates accurate weight compensation torque as same as the MGC without restrictions of spring arrangement and spring constant, because it consists of Pascal's principle-driven mechanism. Next, it is shown that the new mechanism can be installed into heavy manipulators or carry heavy loads while ensuring high rigidity and safety, since there is no risk for amputation of wire. Finally, the new mechanism can be easily added other functions as well as compensation mechanism by fluid pipeline networks. From there, the HGC is new device succeeds to change basic concepts of weight compensation mechanism.