We present a closed-loop control strategy for a delta-wing unmanned aerial aquatic-vehicle (UAAV) that enables autonomous swim, fly, and water-to-air transition. Our control system consists of a hybrid state estimator and a closed-loop feedback policy which is capable of trajectory following through the water, air and transition domains. To test our estimator and control approach in hardware, we instrument the vehicle with a minimalistic set of commercial off-the-shelf sensors. Finally, we demonstrate a successful autonomous water-to-air transition with our prototype UAAV system and discuss the implications of these results with regards to robustness.
Due to advances in technology, especially in the remote-controlled aircraft domain, several unmanned aerial-aquatic vehicles have emerged in the past few years @cite_4 . These vehicles, which span the air and water domains, have been the subject of both design studies and hardware demonstrations. Many design strategies have focused on novel propulsion mechanisms. In @cite_10 , the authors develop a quadcopter which can both swim and fly, and is able to transition between the two domains via a novel propeller design. In @cite_17 @cite_15 @cite_5 , the authors develop a fixed-wing UAAV which uses a water-bottle rocket-like propulsion mechanism to exit the water. Some of the same authors present a novel gearbox design to enable multi-domain locomotion with a single propeller in @cite_6 . In @cite_9 , the authors propose a flapping multi-domain wing design and discuss its implications for multi-domain locomotion. Researchers have also engaged in structural analysis of these aerial-aquatic systems. For instance, in @cite_0 , the authors present a computational analysis of a fixed-wing UAAV impacting the water during water-entry.
@cite_4 @cite_9 @cite_6 @cite_0 @cite_5 @cite_15 @cite_10 @cite_17
2587335294 2754138574 1700946486 2541583107
Aerial–aquatic locomotion would allow a broad array of tasks in robot-enabled environmental monitoring or disaster management. One of the most significant challenges of aerial–aquatic locomotion in mobile robots is finding a propulsion system that is capable of working effectively in both fluids and transitioning between them. The large differences in the density and viscosity of air compared to water means that a single direct propulsion system without adaptability will be inefficient in at least one medium. This paper examines multimodal propeller propulsion using computational tools validated against experimental data. Based on this analysis, we present a novel gearbox enabling an aerial propulsion system to operate efficiently underwater. This is achieved with minimal complexity using a single fixed pitch propeller system, which can change gear underwater by reversing the drive motor, but with the gearing arranged to leave the propeller direction unchanged. This system is then integrated into a small robot, and flights in air and locomotion underwater are demonstrated. This paper presents test results and performance characterization of the first fixed-wing unmanned vehicle capable of full cross-domain operation in both the aerial and underwater environments with repeated transition and low-energy loitering capabilities. This vehicle concept combines the speed and range of an aircraft with the persistence, diving capabilities, and stealth of a submersible. The paper describes the proof-of-concept vehicle including its concept of operations, the approaches employed to achieve the required functions, and the main components and subsystems. Key subsystems include a passively flooding and draining wing, a single motor and propeller combination for propulsion in both domains, and aerodynamic–hydrodynamic control surfaces. Experiments to quantify the vehicle performance, control responses, and energy consumption in underwater, surface, and flight operation are presented and analyzed. Results of several full-cycle tests are presented to characterize and illustrate each stage of operation including surface locomotion, underwater locomotion, water egress, flight, and water ingress. In total, the proof-of-concept vehicle demonstrated 12 full-cycle cross-domain missions including both manually controlled and autonomous operation. Bio-inspired vehicles are currently leading the way in the quest to produce a vehicle capable of flight and underwater navigation. However, a fully functional vehicle has not yet been realized. We present the first fully functional vehicle platform operating in air and underwater with seamless transition between both mediums. These unique capabilities combined with the hovering, high maneuverability and reliability of multirotor vehicles, results in a disruptive technology for both civil and military application including air water search and rescue, inspection, repairs and survey missions among others. The invention was built on a bio-inspired locomotion force analysis that combines flight and swimming. Three main advances in the present work has allowed this invention. The first is the discovery of a seamless transition method between air and underwater. The second is the design of a multi-medium propulsion system capable of efficient operation in air and underwater. The third combines the requirements for lift and thrust for flight (for a given weight) and the requirements for thrust and neutral buoyancy (in water) for swimming. The result is a careful balance between lift, thrust, weight, and neutral buoyancy implemented in the vehicle design. A fully operational prototype demonstrated the flight, and underwater navigation capabilities as well as the rapid air water and water air transition. The ability to collect water samples rapidly with aerial–aquatic robots would increase the safety and efficiency of water health monitoring and allow water sample collection from dangerous or inaccessible areas. An aquatic micro air vehicle (AquaMAV) able to dive into the water offers a low cost and robust means of collecting samples. However, small-scale flying vehicles generally do not have sufficient power for transition to flight from water. In this paper, we present a novel jet propelled AquaMAV able to perform jumpgliding leaps from water and a planar trajectory model that is able to accurately predict aquatic escape trajectories. Using this model, we are able to offer insights into the stability of aquatic takeoff to perturbations from surface waves and demonstrate that an impulsive leap is a robust method of flight transition. The AquaMAV uses a CO @math powered water jet to escape the water, actuated by a custom shape memory alloy gas release. The 100 g robot leaps from beneath the surface, where it can deploy wings and glide over the water, achieving speeds above 11 m s.