Flight dynamic modeling and control for a telescopic wing morphing aircraft via asymmetric wing morphing

In this paper, a sliding mode flight controller is formulated in order to enhance the lateral maneuverability for a tailless telescopic wing morphing aircraft by using additional asymmetric wing telescoping. Based on the nonlinear time-varying equations of motion and the approximate aerodynamic model obtained by wind tunnel tests, a nonlinear time-varying model with coupling between aerodynamic parameters and control inputs is established and the open-loop dynamic response characteristics are analyzed. According to the difficulty of precise aerodynamic modeling during both sides of wing telescoping, the sliding mode control approach is used to design the control law to track maneuver reference command, which has a low requirement for modeling precision and is suitable for the nonlinear time-varying system. In addition, the control inputs are allocated to asymmetric wing telescoping and aerodynamic control surfaces based on the minimum energy method. The closed-loop simulation results of a roll agility maneuvering called “T90 maneuvering” are presented. The results show that a larger roll angular velocity is produced and the control surfaces in the maneuvering flight can maintain a large control margin, which means the maneuverability is significantly improved and the control burden of the aerodynamic control surfaces has been reduced compared with the aircraft without use of telescopic wings; moreover, the robustness of the sliding mode controller is verified by simulation of aerodynamic perturbations.