Nonlinear Trim and Stability Analysis for a Wingtip-Chained Aircraft
Jiamin He, Haojie Liu, Rui Huang, Yonghui Zhao
Abstract: This study investigates the nonlinear trim and stability analysis of a Wingtip Chained Aircraft (WCA), which is a novel configuration of n rigid unmanned aerial vehicle units connected by the wingtip hinge mechanism. A nonlinear flight dynamics modeling approach by integrating Kane’s method and a quasi-steady lifting-line model is proposed to establish the governing equations of the n-unit aerial multibody system, where torsional springs are used to describe the hinge mechanism that allows relative roll motions between connected units. The nonlinear aeroelastic trim analysis of the WCA with distributed power and redundant control surfaces is conducted by solving the over-determined trim system via an optimization method. The dynamic stability behavior of the WCA around a specific static equilibrium configuration is obtained by performing eigenvalue analysis under small-perturbation assumption. In order to demonstrate the proposed methodology, the flight dynamics behavior with respect to the torsional stiffness are investigated for a 5-unit WCA. Numerical results indicate that the equilibrium configuration and the dynamic stability characteristics are closely related with the hinge stiffness.
