涵道式无人飞行器的动力学建模与运动稳定性分析

Dynamics Modeling and Stability Analysis of a Ducted Fan Unmanned Aerial Vehicle

涵道式无人飞行器在起飞/着陆过程中,由于近地空间复杂气流等扰动的作用,极易产生钟摆振动、精度降低、失控坠落等运动失稳现象。针对求解动力学方程或Lyapunov直接法分析系统运动稳定性存在着方程难以求解及Lyapunov函数难以构建等问题,通过Lyapunov指数方法建立了飞行器结构参数与系统运动稳定性之间的量化关系,为指导系统的机械结构设计及控制系统优化,提高其系统的可靠性和稳定性提供参考。该方法与Lyapunov直接法相比,具有可构建性、计算过程简单等特点。

The problems of dynamic stability of the ducted fan unmanned aerial vehicles,such as cornering,shake,loss of accuracy of command tracking and loss of control,were very easy to arise during take-off and landing due to the disturbances from the complex airflow.Analyzing the dynamic stability of this system based on solving the dynamics equation or the direct method of Lyapunov was very difficult due to being difficult to solve the equations and to derivate Lyapunov function and so on.Hence,a Lyapunov exponent approach was used to establish the quantitative relationship among the structural parameters of a unmanned aerial vehicle and its dynamic stability for guiding the design of the vehicle＇s mechanical structure and the optimization of its stability control by using the relationship,which provided important basis for promoting the dynamic stability and reliability of this system.Compared with the direct method of Lyapunov for analyzing of the stability,the method of Lyapunov exponents is easier to build and the calculation process is simpler.