用机体振动诊断直升机旋翼复合不平衡故障研究

Novel Method for Diagnosis of Helicopter Rotor Compound Imbalance Fault by Using Fuselage Vibrations

在用机体振动诊断旋翼单一不平衡故障研究基础上,提出了仅借助机体振动信号诊断旋翼复合不平衡故障的新方法。证明了从旋翼复合不平衡故障空间到多点机体振动空间存在一对一映射关系。利用3个BP神经网络诊断故障类别和程度,利用机体振动一阶谐波分量的初相角确定失衡桨叶方位。模型旋翼实验结果表明,该方法可行、有效。

The diagnosis of helicopter rotor imbalance faults, including mass and aerodynamic imbalance, has generally depended on the measurements of the flap and lead/lag track of the tip of the rotor blades and the fuselage vibration at 1/rev frequency. It is of practical significance to simplify the balancing procedures. A method is proposed for the diagnosis of multiple imbalance faults on the helicopter rotor by using information extracted from rotor induced fuselage vibrations without any rotor blades track measurements and associated optical devices. It is proved that there is an injection of rotor imbalance multi-faults space into the rotor induced fuselage vibration space. Three BP neural networks are used to identify the injection, one BP neural network identifies the types of the faults, and the other two detect the extent of the faults. Those networks are trained and tested by measured fuselage vibration signals in the frequency domain. The location of the unbalanced blade is identified by the initial phase of the fundamental harmonic component of the measured data. Tests are conducted to verify the above approach. The results of the tests show the feasibility and validity of the method.