Time-Domain Feedforward Control for Gust Response Alleviation Based on Seamless Morphing Wing

This paper presents a time-domain feedforward control scheme for alleviating gust response by using a seamless wing morphing technique. The morphing device is composed of a variable cambered trailing edge flap and two symmetrically disposed seamless transition structures. The former is explicated by spatiotemporal polynomial surface fitting, which maintains the medium camber's length. The gust response of the elastic wing is calculated by a modal superposition-based fluid-structure interaction method, and its accuracy is verified with wind tunnel experiments' results. Afterward, the effect of the time delay on gust response is investigated. The influence of freestream velocity and gust amplitude on the time delay is revealed for an optimal feedforward controller. The results demonstrate that the freestream velocity affects the phase offset between the sinusoidal gust and the wing-morphing motion, and the phase offset of 0 deg corresponds to the optimum time delay. Furthermore, an attached leading-edge vortex arises in the case of a large-amplitude gust, but it does not significantly affect the time delay. The vorticity and pressure distributions in the flowfield indicate that the wing morphing influences the attached leading-edge vortex's spanwise size and changes the aerodynamic distribution, thereby affecting the gust response.