1,720,985 research outputs found
Aquatic Escape: Repeatable Escape with Combustion
No full textSeveral systems have been developed with aerial-aquatic locomotion capabilities but without demonstrating consecutive transitions to flight from water. Moreover, while some multirotor vehicles possess the ability to operate in both air and water [108, 109], the transition to flight is typically constrained to very calm sea conditions. Fixed-wing robots able to transition dynamically between water and air through high-power thrust bursts represent a low-cost, versatile and more reliable solution. Compared to multirotor vehicles, this approach that would simultaneously result in an increased flight range and allow for aquatic escape in a wider variety of conditions.LS
Sailing and Flying with a Multimodal Robot
No full textThe field of aerial-aquatic robotics promises tremendous benefits in data collection as well as unmatched flexibility and remote access. However, the majority of existing aerial-aquatic robots are unable to perform scientific tasks at significant depth, limited by the weight penalty that any pressure resistant container would add. In addition, sealing of an actuated robot is difficult, again adding significant weight to small systems. Wireless communication is a major challenge for underwater robots and certainly poses great constraints to operation at distance. Lastly, underwater propulsion is often highly inefficient due to geometries optimised for flight [109]. Indeed, most aerial-aquatic vehicles either have severely limited water range and operation, stay in very shallow waters or function only in de-ionised water. Too often, the benefit of underwater locomotion is overshadowed by the weight, and complexity increases that are required for reliable operation. This negatively impacts flight performance.LS
Diving from Flight
No full textHaving measured the longitudinal aerodynamics of the AquaMAV in wind tunnel tests (cf. Chap. 7 ), the data gathered can then be used to analyse the dive performance of the vehicle, as well as estimate and evaluate its dynamic properties. As in Sect. 6.4, we begin by considering a quasi-steady state model, where, furthermore, the aerial and aquatic phases are considered separately and transition phases are omitted. This model is used to obtain planar dive trajectories for both the purely aerial and the purely aquatic phase, providing a clear overview of the achievable performance of the robot. In the second part of the chapter, a more detailed model of the vehicle is developed that accounts for some dynamic effects and explicitly includes the air-to-water transition. The latter model is used to obtain more insight into the vehicle dynamics and into the impact phase. It also serves as a basis for simulations covering several envisaged mission stages.LSR1s
Airframe Design for Plunge Diving
No full textIn this chapter the design of a plunge diving AquaMAV is detailed. This enhanced AquaMAV prototype is capable of propelled flight, wing retraction for diving into water and jet propelled aquatic escape. The selection process for key components is detailed, as well as the specific attributes necessary for aerial-aquatic locomotion. The AquaMAV includes some limited automation, to allow the robot to self launch when in water, where radio communication is challenging.LS
Practical Tips for Building Aerial-Aquatic Robots
No full textThis book would not be complete without a chapter on practical hardware and software elements used throughout the presented robots. We hope that this can serve as a rough toolbox for aerial-aquatic vehicle development, and cover some of the prototyping choices that are often under-reported in academic literature, but consume outsize research time.LS
Aquatic Escape: Fast Escape with a Jet Thruster
No full textIn a previous chapter an idealised water jet thruster was analysed, and it was argued that the most effective system would use large pressures to drive a small volume of water. In this chapter a more detailed physical model of water jet propulsion will be introduced, and the key design features of a jet thruster prototype detailed. Consistent static thrust from the fabricated device is then demonstrated.LS
Efficient Water-Air Propulsion with a Single Propeller
No full textIn the previous chapters, aquatic launch and dives into water with small flying robots have been demonstrated. An AquaMAV prototype was presented which was capable of self propelled-flight in air and able to escape water, but this robot had no means of propelling itself beneath the surface. To add aquatic locomotion it is attractive to use the same propulsion system as is used for flight, as this reduces the weight and complexity of the system. However, the increase in load on the propeller in a denser fluid results in much slower rotation speeds, and means a significant loss of motor efficiency.LSR1s
The Physics of Aerial Aquatic Locomotion
No full textThis chapter presents an overview of some fundamental physical laws and concepts at play in generic, as clarified in Figs. 5.1 and 5.2. The vehicle-specific physics are then introduced in the following chapters and form the basis for locomotion derived for the different vehicles presented.LS
Why Swim and Fly?
No full textWe live on a water-covered planet that is facing rapid change, both globally and locally, due to a combination of human behaviour and natural phenomena [31]. Understanding these changes requires in-depth scientific understanding of our environment. Key to enabling this is the fast, accurate and repeated provision of extensive physical data. However, obtaining dependable geospatial data is itself frequently a challenge, requiring new sensing approaches or considerable adjustments to existing methods.LS
Multirotor Aircraft and the Aquatic Environment
No full textThe previous chapters presented hybrid robot concepts and prototypes relying on the use of fixed wings for lift generation. The higher flight efficiency of such devices makes them suitable for covering large distances and can even serve to extend their locomotion envelope (see Chap. 11 ).LSR1s
- …
