  This paper deals with the simultaneous gust and maneuver load alleviation
problem of a seamless active morphing wing. The incremental nonlinear dynamic
inversion with quadratic programming control allocation and virtual shape
functions (denoted as INDI-QP-V) is proposed to fulfill this goal. The designed
control allocator provides an optimal solution while satisfying actuator
position constraints, rate constraints, and relative position constraints.
Virtual shape functions ensure the smoothness of the morphing wing at every
moment. In the presence of model uncertainties, external disturbances, and
control allocation errors, the closed-loop stability is guaranteed in the
Lyapunov sense. Wind tunnel tests demonstrate that INDI-QP-V can make the
seamless wing morph actively to resist ``1-cos'' gusts and modify the spanwise
lift distribution at the same time. The wing root shear force and bending
moment have been alleviated by more than 44% despite unexpected actuator fault
and nonlinear backlash. Moreover, during the experiment, all the input
constraints were satisfied, the wing shape was smooth all the time, and the
control law was executed in real time. Furthermore, as compared to the linear
quadratic Gaussian (LQG) control, the hardware implementation of INDI-QP-V is
easier; the robust performance of INDI-QP-V is also superior.
