Direct load sensitive electro-hydrostatic force control actuator for asymmetric cylinder with switch valve: Design and simulation

Full scale aircraft structural testing is the only way before the maiden flight of aircraft. And it is essential to insurance of aircraft normal service. As part of the full scale aircraft structural testing, fatigue testing is the only effective method of judging the safety of aircraft service life. In the present situation, fatigue testing uses multiple valve controlled hydraulic cylinder driven by a concentrated oil source, which need to improve efficiency urgently. Thus, there is huge potential of energy saving in fatigue testing. Furthermore, due to aircraft structural rigidity is relatively low, namely load displacement is relatively large, we need to choose asymmetric cylinder. This paper proposes a proprietary method for fatigue testing which is direct load sensitive electro-hydrostatic force control actuator for asymmetric cylinder with switch valve. As a pump control system, it improves efficiency and reduces energy loss of the system. The asymmetry of the control and flow for asymmetric cylinder is solved by differential drive. In addition, this system can work at the optimal working point, improve working conditions of the system and reduce the heating by introducing the load sensitive sectors. The simulation results demonstrate that the designed force control electro-hydrostatic actuator (EHA) can totally meet the requirement of loading force, and can be widely used in aircraft structural loading test system.