Design and Motion Control of Fully Variable Morphing Wings

The ability to vary the geometry of a wing to adapt to different flight conditions can significantly improve the performance of an aircraft. However, the realization of any morphing concept will typically be accompanied by major challenges. Specifically, the geometrical constraints that are imposed by the shape of the wing and the magnitude of the aerodynamic and inertia loads make the usage of conventional mechanisms inefficient for morphing applications. This paper presents the design of a novel underactuated parallel mechanism, which addresses such concerns. This mechanism, which can be set up in a modular fashion, offers controlled motion in all six spatial degrees of freedom while providing multiple degrees of fault tolerance with only four actuators. The main feature of the design is the usage of active and passive linearly adjustable members to replace the structure of a conventional wing box. These members provide the necessary stiffness and load-bearing capabilities for the wing. With the exception of the skin no additional structure would be required, leading to a relatively light-weight design for the morphing wing. Additionally, an optimal motion control algorithm for minimum energy actuation is proposed based on the kinematics and statics of the mechanism. Finally, the effectiveness of the proposed design and motion control is demonstrated through a simulation followed by the presentation of a multimodule prototype for a wing tip morphing application.