The fault-tolerant operation of Electro-Mechanical Actuator (EMA) system with the hybrid redundant structure

In this paper a hybrid quad-redundant Electro-Mechanical Actuator (EMA) used in the aircraft is researched, which is composed of two brushless DC motors with two sets of control channels, driven by four independent power electronic units, the output torque is coupled through the mechanical transmission device. The quad-redundant configuration is introduced into the power electrical unit which is the weakness of the reliability in the system, and it exists the "Fail-Op, Fail-Op" fault tolerant operation capability. The principle of the EMA is analyzed, the fault tolerant operation modes and control methods are discussed in the paper. The analysis result of the reliability is given at last. The research results show that the EMA system exists the high fault tolerant capability after adopting the hybrid redundant structure, and the mission reliability of the system is increased; The rationality of this redundant structure is also validated through the reliability analysis, this system can be used as one of the redundant design of EMA system for future airplane.. © 2008 IEEE.