Failure detection for control surface of aircraft based on electric actuator

A new method for detecting floating and damaged failures for control surface of aircraft based on the information of electric actuator is proposed. The relationship between actuator's armature current and the failure mode is found. It is proved that the armature current will jump to 0 when the control surface is floating, because the hinge torque suddenly changes to 0. And in the damaged failure case, the armature current will decrease proportionally to each increase of the damage area of the control surface rapidly. On the one hand, the characteristics of one electric actuator correspond directly to its corresponding control surface, and the floating/damaged failure is permanent. So there is almost no false and missing alarm. On the other hand, since the change of the armature current is instantaneous, the alarm time is very short. Finally, two illustrative examples are given and the results show that the fault detection time is in 0.2s (20 periods), and this method can be realized in engineering.