Seamless Active Morphing Wing Simultaneous Gust and Maneuver Load Alleviation

TL;DR

This paper introduces a novel control method for seamless active morphing wings that effectively reduces gust and maneuver loads, ensuring smooth wing shape changes and robustness under uncertainties, demonstrated through wind tunnel tests.

Contribution

The paper proposes INDI-QP-V, a new control approach combining nonlinear dynamic inversion, quadratic programming, and virtual shape functions for active morphing wings.

Findings

Successfully alleviated over 44% of shear force and bending moment.

Maintained smooth wing shape and satisfied all input constraints during tests.

Outperformed LQG control in robustness and ease of implementation.

Abstract

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.