Fault tolerant architecture design of EHA

The integrated EHA (electrical hydrostatic actuator) is an important component of the PBW (power by wire) flight control system. Fault tolerant architecture design is necessary to improve the whole reliability of flight control system. Performance parameters were offered by the demand of reliability, mission abort, redundancy, failure management level, performance, weight and size. The failure rate about each EHA's component was calculated. Based on the calculation result, a feasible fault tolerant architecture of EHA was selected. Then the probability of mission abort and loss of control results from the EHA's failure were calculated separately. Calculation results show that the fault tolerant architecture can meet the flight control system's reliability requirement. Detail design about EHA's architecture was given based on the selected EHA's reliability model, and this kind of EHA system's function was described in particular.