EHA controller design based quantitative feedback theory

QFT (quantitative feedback theory) is a robust controller design method. It has good practicability and has been widely used in hydraulic servo control system. After creating the EHA (electrical hydrostatic actuator) ' s model, the inner and outer loop controllers were designed based on QFT. Inner loop controlled motor s rotate speed and ensured that it had good response time. Outer loop controlled the position of flight surface and ensured that it had good robust stability, tracking capability and disturb restraining ability. Design process considered the parameters uncertainty of electronic and hydraulic system, and aero load changing under all flight conditions. Performance bounds defining took all the inner and outer loop requirements into account. Simulation results show that this control system has good robust stability and can restrain the output disturbance efficiently, which can fully utilize some strongpoint of integrated EHA like high torque and power density, easiness to maintain and modularize. It ran greatly improve the performance of flight control system.