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为了获得涵道风扇无人机的动力学特性,设计了一种以涵道风扇为动力的无人机。采用CFD方法,计算了该无人机在各飞行状态下的气动导数。为了求解其在各飞行状态下的纵向稳定性,对其进行了动力学建模。通过小扰动假设,对运动方程进行了线性化处理,进而计算了其模态特性。研究结果表明,该无人机在各飞行阶段均存在不稳定性,且在垂直起降和过渡阶段尤为突出,需要对发动机转速及升降舵偏角施加控制以保证稳定性要求。最后,对该无人机的纵向不稳定性成因给出了相应的物理解释。该研究可为今后涵道风扇无人机的设计提供一定的参考。
In order to obtain the dynamic characteristics of ducted fan UAV, a ducted fan powered UAV was designed. The CFD method was used to calculate the aerodynamic derivative of the UAV under different flight conditions. In order to solve its longitudinal stability in each flight state, it has been dynamically modeled. Through the hypothesis of small disturbance, the equation of motion is linearized and the modal characteristics are calculated. The results show that the UAV has instability in all phases of flight and is particularly prominent in the vertical take-off and landing phases. It is necessary to control the engine speed and elevator declination to ensure the stability requirements. Finally, a corresponding physical explanation of the cause of the longitudinal instability of the UAV is given. This research can provide certain reference for the design of ducted fan UAV in the future.