直升机垂直飞行状态气动参数辨识方法研究

Helicopter aerodynamic parameter identification in vertical flight

准确计算直升机的悬停升限依赖于诸如桨尖损失系数,非均匀旋翼诱导速度分布,旋翼下洗引起的直升机增重效应及发动机与旋翼之间的功率传递系数等气动参数的准确度。然而,由于复杂的旋翼空气动力现象,准确预估以上气动参数有较大难度。本文提出了一种确定直升机垂直飞行状态上述气动参数的方法,该方法通过建立直升机垂直飞行状态的运动方程,实测直升机垂直飞行时的相关信息,采用参数辨识的方法得到直升机垂直飞行时的气动参数,然后,利用辨识结果确定直升机的悬停升限。结果表明该方法能有效地确定直升机垂直飞行时的气动参数及相应的悬停升限,且具有飞行试验简便,不受直升机装载和外界环境条件变化限制的特点。

In order to calculate the helicopter hover ceiling in OGE precisely, some aerodynamic parametem, such as tip loss effect, induced velocity distribution, the effect of rotor downwash on the fuselage and power transfer of engine into rotor, must be treated carefully. However, to precisely predict these parameters is not easy due to complicated rotor aerody- namic problems. In this paper a method to identify these aerodynamic parameters is proposed by means of vertical flight test. To the end, a mathematical model for aerodynamic parameter identification is developed. Flight tests are conducted and the corresponding data are measured and processed. The parameter identification algorithm suitable for flight test data is discussed and the identified results are obtained. Based on the identified aerodynamic parameters the tested helicopter hover ceiling in OGE is settled. The results show that the method can efficiently identify the aerodynamic parameters as well as the helicopter hover ceiling in OGE.