Determining allowable parametric uncertainty in an uncommon quadrotor model for closed loop stability

Authors: MEHMET BASKIN, MEHMET KEMAL LEBLEBİCİOĞLU

Abstract: In this article, control oriented uncertainty modeling of an uncommon quadrotor in hover is discussed. This quadrotor consists of two counter-rotating big rotors on longitudinal axis and two counter-rotating small tilt rotors on lateral axis. Firstly, approximate linear model of this vehicle around hover is obtained by using Newton--Euler formulation. Secondly, specific uncertainty is assigned to each parameter. Resulting uncertain model is converted into a linear fractional transformation framework for robustness analysis. Next, the most critical uncertain parameters in terms of robust stability in a proposed quadrotor model are investigated using $ \mu $ sensitivities. Finally, skewed-$ \mu $ analysis determines maximum possible uncertainty bounds for model parameters that are difficult to identify accurately.

Keywords: Parameter uncertainty, sensitivity analysis, quadrotor, structured singular value, unmanned aerial vehicle

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