Dynamic Characteristics of a Load-Sensing Hydraulic System : Experiment and Simulation

Abstract

A load-sensing hydraulic system is one of the most effective means to save energy. Such a system has been successfully used in construction machinery and injection molding machines. This kind of system, however, has demerit that it often falls into instability, which may be caused by the interaction between the dynamics of the load-sensing mechanism and that of the load. It is important, therefore, to investigate the dynamic characteristics of the system. In this study, both experiment and simulation are performed in the case where the friction characteristics of an actuator strongly affect the dynamic characteristics of the system. This system is simulated using bond graphs, and computation is carried out using a program named BGSP which was developed in Japan. By comparing experimental and computed results, a suitable model of the system is obtained. Using this model the overall efficiency of this system is calculated, taking into consideration the dynamic characteristics of the system.