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.
Few of the approaches mentioned above consider the closed-loop control or estimation strategies necessary for enabling multi-domain locomotion. In @cite_16 and @cite_1 the authors present modeling, simulation and control strategies for a multi-domain quadcopter. Their approach focuses on applying robust control techniques to develop a globally stable switching attitude controller which relies on two different linear models. In @cite_7 , the authors explore hybrid control for the quadrotor UAAV experimentally.
@cite_16 @cite_1 @cite_7
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The complete modeling and simulation of an unmanned vehicle with combined aerial and underwater ca- pabilities, called Hybrid Unmanned Aerial Underwater Vehicle (HUAUV), is presented in this paper. The best architecture for this kind of vehicle was evaluated based on the adaptation of typical platforms for aerial and underwater vehicles, to allow the navigation in both environments. The model selected was based on a quadrotor-like aerial platform, adapted to dive and move underwater. Kinematic and dynamic models are presented here, and the parameters for a small dimension prototype was estimated and simulated. Finally, controllers were used and validated in realistic simulation, including air and water navigation, and the environment transition problem. To the best of our knowledge, it is the first vehicle that is able to navigate in both environment without mechanical adaptation during the medium transitions. I. INTRODUCTION Nowadays, unmanned autonomous vehicles have been the focus of many development efforts, with a large range of applications. The amount of resources applied has improved their capabilities, especially in the military field. Remotely operated or autonomous Unmanned Aerial Vehicles (UAVs), for example, were used in recent military operations around the world (1). But they were also used in non-military activities, like agriculture (2) and surveillance (3). Another important robotic platform are the Unmanned Underwater Vehicles (UUVs), whose the most known are the Remotely Operated Vehicles (ROVs). This kind of vehicles can also be applied in several commercial field operations (4), e.g. oil and gas extraction in ultra deep waters (5). Both kind of vehicles are well adapted to work in their own environment (air and water, respectively), but some situations may require a single vehicle capable of working in both environment. Such requirement commonly appears when is necessary to perform maintenance on partially or fully submersing structures, as ship hull or risers. A typical approach includes using auxiliary vessels to transport ROVs that will make the inspection of offshore target regions. This problem is harder in partially submersed structures. In such situations, where the usage of auxiliary ships is difficult and expensive, underwater robots equipped with wheels or tracks are recommended. This paper presents a method for stabilizing the attitude of a Hybrid Unmanned Aerial Underwater Vehicle. Firstly, we present aerodynamic and hydrodynamic models for the angular motion of our robot, discussing effects like buoyancy force and added inertia. Next, we apply robust control techniques for both environment, aerial and underwater, based on linear uncertain models with only four vertices and well-defined stability criteria, such as D-stability and ℋ 2 performance. Gain matrices K air and K wat are computed and the attitude of the vehicle at the hovering operation point for each environment is controlled, respectively. Finally, a procedure is proposed to check the global stability for the switching control case, when the robot changes from air to water (or vice-versa). Numerical simulations with disturbances and switching control are presented to show the stability at different initial conditions. Abstract Modeling and control of a multi-medium unmanned vehicle capable of seamless operation in air or underwater is introduced in this paper. The multi-medium system is treated as a hybrid system with continuous dynamics while performing in both air and underwater, and discrete jumps in the medium density during the transitions. The continuous dynamics are modeled by the Newton–Euler formalism, taking into account the effects of the buoyancy and drag phenomena, normally neglected in aerial vehicles. A hybrid controller is designed for trajectory tracking considering the full system, including a transition strategy to assure the switching between mediums. Stability analysis for the full system is provided using hybrid Lyapunov and invariance principles. The performance of the control strategy is validated through simulations. Finally, an experimental platform consisting of a multirotor in an octo-quadcopter configuration was developed and some preliminary experimental results are introduced, showing the vehicle performing in air, underwater and through the transition.