Design and experiment of a multimodal aerial aquatic vehicle with morphing wing and tilting rotors

Aerial aquatic vehicles have wide prospects in scientific and industrial fields because of their cross-domain locomotion ability. To improve the operation capacity of aerial aquatic vehicles, a novel multimodal hybrid vehicle was proposed in this paper. The vehicle combined the advantages of fixed-wing aircraft and multirotor aircraft. Owing to the special morphing wing and tilting rotors mechanism, the vehicle was reconfigurable to adapt to a variety of missions, including long distance flight, vertical take-off and landing, and underwater locomotion. The structure of the hybrid vehicle was designed, and the operating method in different modes were discussed. Then the kinematic and dynamic models were analyzed in terms of fixed-wing flight, multirotor flight, and underwater operation modes, respectively. The attitude control and a control allocation algorithm were established for locomotion control. Finally, the experiments of air flight, morphing wing, and underwater motion were conducted. The results showed that the hybrid aerial aquatic vehicle performed good flight stability and could move freely underwater. The morphing wing could fold and expand itself for resistance reduction and long-distance flight, respectively. The multimodal locomotion experiments verified the feasibility of the novel aerial aquatic vehicle and the control strategy.