Application of direct actuated digital servo valve in electrohydraulic static loading system

Structure static testing is an important means to study the static characteristic of complex engineering structure. Electrohydraulic stactic loading system is the singnificant equipment of the testing. With its function of transfering low-power electrical singal to large-power hydraulic output quickly and precisely, the servo valve plays a key role in an electrohydraulic servo control system and dominates to a large extent the performance of the whole control system. Conventional electrohydraulic servo or proportional control is subject to the nonlinearites of their electro-mechanical interface, such as hysteresis, saturation and finite resolution. In this paper, a direct actuated digital servo valve was applied in electrohydraulic static loading system. It can be driven directly by computer needn´t D/A and has the advantages of simple structure, high tolerance to contamination and high reliability. Practical load-experiment results show that the static loading system with a direct actuated digital servo valve can work steadily and reliably and possess high accuracy and fast response.