Pressure feedback effects of electro-hydraulic actuator system

Vibration test of electro-hydraulic actuator is widely used in the field of industry like large dynamic system to guarantee the performance of the system. As the system is working under the high speed condition, the dynamic vibration test is required naturally. The field of relevant industry involves not only general industry but also aircraft, military, running vehicle industries. Large amount of torque is necessary for the vibration test in terms of large dynamic system. Because of that, an electro-hydraulic system is adopted to satisfy the condition. [1-2] Electro-hydraulic actuator system has strength in high-power even though there are diverse nonlinear elements exist. For instance, non-linearities of loaded pressure, flow gain and friction which is related to piston and cylinder of the actuator. Also, resonance problem is exist. Vibration test is performed in the range of wide frequency range. However, there exists resonance problem occurred within the range the electro-hydraulic actuator is applied. In this research, pressure feedback is discussed to identify the dynamic characteristic of the system. In specific, damping ratio has been considered to deal with the resonance problem. Pressure feedback is working as numerical damping in the electro-hydraulic system. The pressure feedback effect will be covered both theoretically and experimentally in this research.