A Morphable Aerial-Aquatic Quadrotor with Coupled Symmetric Thrust Vectoring

Hybrid aerial-aquatic vehicles have the unique ability of travelling in both air and water and can benefit from both lower fluid resistance in air and energy efficient position holding in water. However, they have to address the differing requirements which make optimising a single design difficult. While existing examples have shown the possibility of such vehicles, they are mostly structurally identical to normal aerial vehicles with minor adjustments to work underwater. Instead of using rotational acceleration to direct a component of thrust in surge and sway, we propose a quadrotor based vehicle that tilts its rotors about the respective arm so that a larger component of thrust can be directed in the lateral plane or in the opposite direction without rotating the vehicle body. A small-scale prototype of this design is presented here, detailing the design considerations including mechanical actuation, static stability and waterproofing.