Modeling and Longitudinal Stability Analysis of Tethered Lifting-Wing Quadcopters

In this paper, the longitudinal stability of the tethered lifting-wing quadcopter, a new type of tethered UAV, is investigated. The tethered lifting-wing quadcopter has the characteristics of both the kite and tethered multicopter, which has longitudinal stability under suitable design parameters. In this paper, the Euler-Lagrange method is used to build a longitudinal dynamic model of the tethered lifting-wing quadcopter. The equilibrium state under different wind speeds is discussed with the constant of rotor force and pitch angle. Meanwhile, the eigenvalues of the Jacobi matrix in each equilibrium state are analyzed to determine whether the current equilibrium state is statically stable. The reasonable range of bridle angle and lifting-wing installation angle is summarized to make the tethered lifting-wing quadcopter as stable as possible. The analysis shows that tethered lifting-wing quadcopters have similar static stability compared to the kites.