Study of the Electro-hydraulic Load Simulator Based on Flow-Press Servo Valve and Flow Servo Valve Parallel Control

The superfluous force seriously affects the dynamic load precision of the electro-hydraulic load simulator. Aiming at this question, the work principle of the electro-hydraulic load simulator was analyzed, and the bond graph models of the flow servo valve, hydraulic cylinder and load were established. These models sufficiently contain the higher-order nonlinear dynamic character of the electro-hydraulic servo valve and describe the time variant character of the liquid capacitance of two cavities in hydraulic cylinder. Then the bond graph model of the electro-hydraulic load simulator system was established by combining the above bond graph models. In order to study the performance of the electro-hydraulic load simulator parallel controlled by the flow-press servo valve and the flow servo valve, and to study the effect of eliminating the superfluous force by this parallel control way, the structure and the working principle of the flow-press servo valve was analyzed, and the bond graph model of the electro-hydraulic load simulator parallel controlled by the flow-press servo valve and the flow servo valve was established. The simulation and experimentation study shows that the double servo valves parallel control method is very efficient to eliminate the superfluous force of the electro-hydraulic load simulator and is very obvious to improve the system performance of dynamic load. The study of simulation and experimentation also prove that the bond graph models are correct.