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Establishment and Simulation of Twelve-Degree-of-Freedom Model for UAV Parachute Recovery System

In the UAV parachute recovery process, the UAV and the parachute have always been in the state of dynamic balance, so it is difficult to deal with the constraint between them. In order to solve this problem, the UAV parachute recovery system was divided into three parts:the parachute, riser and UAV. The extension length of riser was obtained by the velocity relationships of the riser connection points. The riser tension was obtained by the product of the elastic coefficient and the extension length of the riser. And it was applied to the parachute and UAV systems respectively. Finally, based on the Newton-Euler equation, the 12-DOF model of UAV parachute recovery system was established, in which the unsteady aerodynamic model of the UAV from the forward flight to the steady descents was established based on the ONERA equation. The simulation and test results shows:the 12-DOF model is consistent with the results of the experimental data, which verifies the accuracy of the 12-DOF model. The 12-DOF model is more accurate than the past 6-DOF model. This model established in this paper can provide reference for the selection of parachute in the UAV parachute recovery system and the determination of the landing point of the UAV.