The deadband analysis of the electro-hydraulic actuator of the motor-pump coordinated control

The electric-hydraulic actuator (EHA) of the motor-pump coordinated control is mostly applied into the flight control system, and it is a kind of power-by-wire (PBW) actuator with removing the central hydraulic power supply. The actuator system remains the hydraulic power partially, so the system has the characteristics of the hydraulic system such as: the compressibility of the hydraulic oil, friction and internal leakage of the hydraulic components etc., so the system possesses the inevitable deadband. A lot of the current literatures have expounded the deadband of the hydraulic system, but the deadband of the EHA is not fully elaborated, for it is very complicated system. Much analysis of the electric-hydraulic actuator didn´t include the deadband problem. In this paper the fully analysis will be given, and many aspects including the deadband of the system will be thought over. The reason of the deadband will be fully elaborated, and the PD controller of the inner high-gain is applied into the system of the motor-pump, and it improves the performance for a certain extent, and the foundation for further research is built for the higher performance of the electro-hydraulic actuator.