Singular dynamics for morphing aircraft switching on the velocity boundary

Abstract It has singularity problem for morphing aircraft to switch its structure in an infinitesimal short time. Many physical parameters such as aerodynamic coefficients and moment of inertia will be altered, and the thrust of aero engine may be different for different states of morphing aircraft. For a typical case, the sweep angle of wing changes to a relative large angle when the speed of morphing aircraft is higher than a critical speed, while it switches to a small angle for the speed of such an aircraft below the critical speed. It could have possibility that the speed of such a morphing aircraft chatters around the critical speed. If it is in unmanned operation, the aircraft will switch its structure in a high frequency for the aforementioned condition, which may be a high risk for the control and dynamic of the morphing aircraft. Therefore, it is necessary to study whether the morphing aircraft should switch its structure when the speed arrives the critical speed. To simplify the problem, the switchability of such a morphing aircraft will be studied based on the dynamical system in the longitudinal direction. The analytical passable and non-passable conditions for flow switching on the velocity boundary for such a morphing aircraft will be developed. For non-passable flows, the analytical conditions for onset and vanishing for flow sliding on the velocity boundary will also be given. Mapping structure will be used to describe the periodic motions of dynamical system for such an aircraft. Numerical simulations will be carried out to show the complexity for such a switchability problem. It will be found that with the development of switchability conditions, the morphing aircraft could obviously decrease the chatter phenomenon compared with the direct switch case.