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针对无人机的飞行安全这一典型的系统工程问题,从目前国际惯用的非线性控制和辨识建模的角度出发,通过建立波动信息能量函数模型并结合模糊评价理论,量化分析了DFT变换对无人机系统建模和控制的不稳定性影响;通过对无人机非线性运动模型的分析,说明了该模型中各参数的不稳定关系和不稳定特征,提出了符合Shilnikov定理的三阶非线性模型;通过构造综合影响函数和进行参数配置,确定了无人机非线性运动模型的若干鞍焦点和异宿轨道,从而找到了该系统的若干混沌运动轨道.最后通过仿真证明了直升机非线性运动模型的混沌运动特征和运用DFT辨识模型进行控制的条件下出现无人机不稳定性现象,说明了无人机非线性运动模型混沌运动的存在性及DFT变换中的高阶能量损失和参数配置方式的共同作用模式可构成无人机系统不稳定性的条件.
According to the typical system engineering problem of UAV flight safety, from the perspective of the current international non-linear control and identification modeling, by establishing the energy function model of fluctuation information and combining with the fuzzy evaluation theory, the DFT transform pair Unmanned aerial vehicle system modeling and control instability; through the analysis of the UAV non-linear motion model, the instability and instability characteristics of the parameters of the model are described, in line with the Shilnikov theorem of the third order Nonlinear model was established by analyzing the influence of helicopter on the non-linear motion of the UAV.A number of saddle focus and heteroclinic orbit of the UAV nonlinear motion model were determined by constructing the comprehensive influence function and parameter configuration, and some chaotic orbits of the system were found.Finally, The chaotic motion characteristics of linear motion model and the UAV instability phenomenon under the control of DFT identification model illustrate the existence of chaotic motion of nonlinear motion model of UAV and the high order energy loss in DFT transform and The common mode of the parameter configuration mode can constitute the condition of UAV system instability.