变转速共轴旋翼载荷建模及实验验证

对共轴双旋翼无人飞行器操纵结构的简化,会引起旋翼载荷变化更加复杂。共轴双旋翼转速控制方法有助于飞行控制系统的实现,但是在飞行控制律设计时,需要透彻了解变转速旋翼的气动载荷变化,建立精准的旋翼载荷模型。本文深入分析了旋翼变转速情况下单旋翼系统和共轴双旋翼系统的旋翼入流分布,建立了单旋翼变转速旋翼载荷计算方法,提出了共轴双旋翼变转速旋翼载荷计算方法。明确了低雷诺数对微型旋翼飞行器的旋翼载荷计算影响,引入雷诺数修正系数完成对旋翼翼型升阻系数气动参数的修正和验证,提高了变转速共轴双旋翼载荷模型的计算精度。设计了一套变转速单旋翼系统和共轴双旋翼系统的旋翼载荷测量实验装置,通过实验测试完成了对共轴双旋翼载荷计算方法的验证,表明了所提出的变转速共轴双旋翼载荷模型和实验测试装置是可信的。

Modeling and Validation of Aerodynamic Loads for Variable RPM Coaxial Rotor

Manipulation structure simplification of co-axial dual-rotor unmanned aerial vehicle (UAV) will result in more complication of rotor load change. Co-axial dual-rotor speed control method is useful for the implementation of flight control system. Thorough understanding of aerodynamic loads change pattern for variable RPM rotor and an accurate rotor load model are essential for flight control law design. In this paper, based on the analysis of rotor inflow distribution of single-rotor and co-axial dual-rotor of variable RPM, a simplified and practical mathematical model of single-rotor was established and a calculation method for co-axial dual-rotor loads was put forward. The impact of low Reynolds number on rotor load calculation of micro-rotor aircraft was analyzed. A Reynolds number correction coefficient was introduced to correct and verify lift-drag coefficient of rotor airfoil aerodynamic parameters. The variable RPM co-axial dual-rotor load model was improved accurately. A set of test equipment for load measurement of a variable RPM single-rotor and coaxial dual-rotor system was designed. Experimental validation of co-axial dual-rotor load calculation method was conducted. Results illustrate that the model of aerodynamic loads for variable RPM co-axial dual-rotor and the measurement test equipment are reliable.