On dynamic characteristics and stability analysis of the ducted fan unmanned aerial vehicles

Abstract

This article researches the improvement of dynamics stability of the ducted fan unmanned aerial vehicles by optimizing its mechanical–structure parameters. The instability phenomenon of ducted fan unmanned aerial vehicles takes place frequently due to the complicated airflow in near-earth space, which easily leads to the stability problems, such as out of control, shaking, and loss accuracy of command tracking. The dynamics equations mirror its dynamics characteristics, which are primarily influenced by the mechanical–structure parameters of the whole system. Based on this, the optimization of mechanical–structure parameters has a significant to improve the dynamics stability of the whole system. Therefore, this article uses the concept of Lyapunov exponents to build the quantification relationship between system’s mechanical–structure parameters and its motion stability to enhance its stability from viewpoint of mechanical–structural parameter design. The takeoff, landing, and hovering stage are respectively studied and the conclusions suggest that the optimization of mechanical–structure parameters can be used to promote dynamics stability.

Neural-Networks Control for Hover to High-Speed-Level-Flight Transition of Ducted Fan UAV With Provable Stability

“…Basically, as a special type of tail-sitter VTOL aircraft, a ducted fan features the same as a rotorcraft at hover or vertical flight, and acts more like a fixed-wing airplane when levelly flying with high-speed [30], [31]. In this part, we give the detailed expressions of all the forces and moments in (3).…”

Quantitative Study of Load Stability of Quadrotor Based on Lyapunov Exponents

“…Furthermore, during the payload delivery process of the quadrotor, changes in parameters and uncertain aerodynamic loads can turn the entire system into a complex, high-order, strongly coupled, nonlinear system [12,13]. However, when traditional direct solving of dynamic equations or the Lyapunov direct method is used for analysis, there are often problems of complex equations difcult to solve and Lyapunov function difcult to construct [14], and it is difcult to give a quantitative relationship between structural parameter changes and system motion stability. Terefore, how to quantitatively analyze the motion stability of a quadrotor during payload delivery has become one of the urgent scientifc issues to be solved currently [15][16][17][18][19].…”