用参数辨识法进行直升机悬停性能拓展

准确计算直升机在不同飞行状态的有效气动参数对于确定直升机飞行性能具有重要意义。然而,由于复杂的旋翼空气动力现象以及直升机状态和环境条件的变化,准确预估气动参数有较大难度。为此,采用无量纲分析法建立直升机悬停状态的数学模型,首先对参数重组,确定了几个悬停状态重要参数,包括气动参数和直升机状态参数;然后,以直-9×型直升机为例,结合实际试飞数据,提出了用最小二乘法对该模型进行参数辨识的方法;最后,通过相关性分析,确定了辨识方法的可行性,并将辨识结果有效地用于直升机悬停性能拓展。结果表明,这种利用参数辨识进行性能拓展的方法是可行的,由于辨识结果是利用实际试飞数据确定的,拓展结果具有较高的可信度。这种数据处理方法可有效减少试飞周期,节约试验成本。

Helicopter Hovering Performance Expansion by Parameter Identification

To calculate accurately the effective aerodynamic parameters of a helicopter in different flight states is of crucial importance to the determination of its flight performance. However, it is not easy to estimate these parameters precisely due to complicated rotor aerodynamics and changing environment and helicopter states. In this article, a non-dimensional mathematic model is built for the helicopter hovering state, and a number of important parameters of the helicopter, including its aerodynamic parameters and certain state parameters, are developed by regrouping. Then, taking helicopter Z-9× as an example, the least squares method is proposed to identify the dynamic parameters of the mathematic model on the basis of actual flight test data. Finally, the identification method is proved valid through feasibility analysis, and these identified parameters are effectively used to expand the helicopter’s hovering performance. The results show that it is feasible to use the parameter identification method to expand helicopter hovering performance, and the expanding results have high reliability since the identified parameters are derived from actual flight data. It is believed that this flight data measurement method can reduce flight test periods and save test cost as well.