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.

Testing and Characterization of a Fixed Wing Cross-Domain Unmanned Vehicle Operating in Aerial and Underwater Environments

Design, fabrication, and characterization of a multimodal hybrid aerial underwater vehicle

This paper presents the HyDrone, a novel concept of hybrid vehicle for aerial and underwater applications. Here, we discuss its geometry and dynamical behavior, concerning their main advantages and constraints. Translation and rotation models in SE(3) are presented, with the respective control laws used to stabilize the system in the air and under the water. Similar to other air/water vehicles in the literature, our robot can also navigate in both environments without mechanical adaptation during the medium transitions. However, our vehicle provides better results when compared to other approaches in the state-of-the-art in terms of underwater navigation efficiency. Simulated results demonstrate the trade-offs associated with our new hybrid platform when compared to other existing hybrid vehicles.

A Novel Concept for Hybrid Unmanned Aerial Underwater Vehicles Focused on Aquatic Performance

Unmanned Aerial Vehicles have undergone rapid developments in recent decades. This has made them very popular for various military and civilian applications allowing us to reach places that were previously hard to reach in addition to saving time and lives. A highly desirable direction when developing unmanned aerial vehicles is towards achieving fully autonomous missions and performing their dedicated tasks with minimum human interaction. Thus, this paper provides a survey of some of the recent developments in the field of unmanned aerial vehicles related to safe autonomous navigation, which is a very critical component in the whole system. A great part of this paper focus on advanced methods capable of producing three-dimensional avoidance maneuvers and safe trajectories. Research challenges related to unmanned aerial vehicle development are also highlighted.

Towards Fully Autonomous UAVs: A Survey.

Aerial-aquatic robots possess the unique ability of operating in both air and water. However, this capability comes with tremendous challenges, such as communication incompatibility, increased airborne mass, potentially inefficient operation in each of the environments and manufacturing difficulties. Such robots, therefore, typically have small payloads and a limited operational envelope, often making their field usage impractical. We propose a novel robotic water sampling approach that combines the robust technologies of multirotors and underwater micro-vehicles into a single integrated tool usable for field operations. The proposed solution encompasses a multirotor capable of landing and floating on the water, and a tethered mobile underwater pod that can be deployed to depths of several meters. The pod is controlled remotely in three dimensions and transmits video feed and sensor data via the floating multirotor back to the user. The `dual-robot' approach considerably simplifies robotic underwater monitoring, while also taking advantage of the fact that multirotors can travel long distances, fly over obstacles, carry payloads and manoeuvre through difficult terrain, while submersible robots are ideal for underwater sampling or manipulation. The presented system can perform challenging tasks which would otherwise require boats or submarines. The ability to collect aquatic images, samples and metrics will be invaluable for ecology and aquatic research, supporting our understanding of local climate in difficult-to-access environments [Video attachment: https://youtu.be/v4xWmEHUSM4].

MEDUSA: A Multi-Environment Dual-Robot for Underwater Sample Acquisition

This paper looks to the natural world for solutions to many of the challenges associated with the design of fixed-wing cross-domain vehicles. One example is the common murre, a seabird that flies from nesting locations to feeding areas, dives underwater to catch prey and returns. This hunting expedition provides an outline of a possible mission for a cross-domain vehicle. While the challenges of cross-domain vehicles are many, the focus of this paper was on buoyancy management and propulsion. Potential solutions to each challenge, inspired by multiple animals that cross between aerial and underwater domains, are investigated. From these solutions, three design concepts are considered, a quadrotor/fixed-wing hybrid, a vertical takeoff and landing (VTOL) tailsitter aircraft, and a waterjet-assisted takeoff vehicle. A comparison was made between the capability of each concept to complete two missions based on the common murres' hunting expedition. As a result of this comparison, the VTOL tailsitter design was selected for further study. In-depth design was conducted and a prototype vehicle was built. The completed vehicle prototype successfully conducted submerged operation as well as four air flights. Flights consisted of egress from water, flight in air, ingress into water in each flight, and water locomotion. A total of 11 min, 23 s of flight time was recorded as well as underwater swims down to 12 ft (3.7 m) below the surface.

https://iopscience.iop.org/article/10.1088/1748-3190/aad48b/pdf

Richard Gritter

Papers

Design and demonstration of a seabird-inspired fixed-wing hybrid UAV-UUV system.