A Method for Aileron Actuator Fault Diagnosis Based on PCA and PGC-SVM

Table 10

Fault analysis of aileron actuator.

Object	Fault mode	Fault cause	Fault phenomenon
Direct driving valve	Force motor coil shutoff	Force motor coil break	Force motor has no power output; the position of valve element is constantly in the neutral position.
	Blockage	Oil pollution	Null bias increases; frequency response decreases; system is unstable.
	Valve element stuck	Oil pollution; Slide valve distortion	The direct driving valve output constant flow; the system pressure decreases.
	Valve leakage	Edge abrasion; Radial valve element abrasion	Null bias increases; gain of system decreases; system pressure decreases; flow noise increases.
	Null bias out-of-tolerance	Inaccurate zero setting	Bias exists when DDV is at null position.
Displacement sensor	Coil break	Cable break	Sensor has no output.
	Constant bias	Iron core of sensor loose	Displacement bias.
Actuator cylinder	External leakage	Sealing washers fail; Hydraulic leakage	The speed of moving parts decreases; system pressure decreases.
	Internal leakage out-of- tolerance	Cylinder abrasion; Oil in high pressure area flow into low pressure area	The speed of moving parts decreases; system pressure decreases; vibration and noise appear.
Electronic amplifier	Gain reduction	Internal faults of electronic amplifier	Magnification notably decreases.