Solutions for flexible wing aircraft´s dynamics model with generalized forces

Small flexible wing aircraft (FWA) uses distributed actuators to deform the wing in order to get a better aerodynamic shape. Traditional model can´t describe the coupling effect the elastic and rigid-body degrees of freedom, and so it is necessary to get dynamics models of an elastic aircraft. At present, Lagrange´s equation and the Principle of Virtual Work are used to generate the equations of motions, and aerodynamic strip theory is then employed to get integral expressions for the generalized forces. Although the accurate models have been achieved, it is a tough work that so many new parameters such as aerodynamic ones can´t be obtained easily. In order to solve these problems, this paper introduces the method of modal analysis in the field of structural theories to calculate the corresponding parameters in the dynamical model of FWA. Without traditional methods which include complex calculations, plenty of experiments and unacceptable errors, the way by using structural modes and generalized coefficients can express the parameters directly. The numerical simulation results show that it is a reasonable and accurate to solve the complicated calculation problem in FWA model. Finally, it will provide references for analysis about FWA model.