As our world is experiencing climate changes, we are in need of better monitoring technologies.
Most of our planet is covered with water and robots will need to move in aquatic environments.
A mobile robotic platform that possesses efficient locomotion and is capable of operating in
diverse scenarios would give us an advantage in data collection that can validate climate models,
emergency relief and experimental biological research. This field of application is the driving
vector of this robotics research which aims to understand, produce and demonstrate solutions
of aerial-aquatic autonomous vehicles.
However, small robots face major challenges in operating both in water and in air, as well as
transition between those fluids, mainly due to the difference of density of the media.
This thesis presents the developments of new aquatic locomotion strategies at small scales that
further enlarge the operational domain of conventional platforms. This comprises flight, shallow
water locomotion and the transition in-between. Their operating principles, manufacturing
methods and control methods are discussed and evaluated in detail.
I present multiple unique aerial-aquatic robots with various water escape mechanisms, spanning
over different scales. The five robotic platforms showcased share similarities that are compared.
The take-off methods are analysed carefully and the underlying physics principles put into light.
While all presented research fulfils a similar locomotion objective - i.e aerial and aquatic motion
- their relevance depends on the environmental conditions and supposed mission. As such, the
performance of each vehicle is discussed and characterised in real, relevant conditions.
A novel water-reactive fuel thruster is developed for impulsive take-off, allowing consecutive
and multiple jump-gliding from the water surface in rough conditions. At a smaller scale, the
escape of a milligram robotic bee is achieved. In addition, a new robot class is demonstrated,
that employs the same wings for flying as for passive surface sailing. This unique capability
allows the flexibility of flight to be combined with long-duration surface missions, enabling
autonomous prolonged aquatic monitoring.