A blimp: first step towards air/ground cooperative robotics

Our long term objectives in field robotics is to tackle the various issues raised by the deployment of heterogeneous autonomous systems, in the context of exploration, surveillance and intervention missions. Within such contexts, aerial robots will undoubtly play a growing role in the near future, not only during the mission preparation phase (in which drones can already gather environment informations for instance), but also on-line, during the mission execution. Aerial robots can then provide the rovers with telecommunications support, as well as with up-to-date informations on the environment. They can also localize the rovers as they evolve within this environment, and even achieve by themselves some of the mission goals.

Why a blimp ?

We recently initiated the development of an autonomous blimp. We are convinced that the ever on-going developments in a wide spectrum of technologies, ranging from actuator, sensors and computing devices to energy and material will ensure lighter than air machines a promising future. There is undoubtly a regain of interest in this domain, as shown by the recent industrial developments on heavy loads transportation projects (such as CargoLifter and the ATG Skycats, not to mention various other prospective transportation projects), and on stratospheric telecommunication platforms.

As for small-size unmanned radio-controlled models, which size is of the order of a few tens of cubic meters, their domain of operation is currently essentially restrained to advertising or aerial photography. But their properties makes them an very suitable support to develop heterogeneous air/ground robotics systems: they are easy to operate, they can safely fly at very low altitudes (down to a few meters), and especially their dynamics is comparable with the ground rovers dynamics, as they can hover a long time over a particular area, while being able to fly at several tens of kilometers per hour, still consuming little energy. Their main and sole enemy is the wind. Some specific applications of unmanned blimps are more and more seriously considered throughout the world, from planetary exploration to military applications, as shown by numerous contributions in the AIAA Lighter Than Air conferences or the Airship Conventions for instance.

Our work

Flight control Our objective is to endow a blimp with the possibility to servo its trajectories on the basis of its state sensors, and in the long term on the basis of the perception of ground elements with cameras.

Environment mapping Mapping the environment with images acquired from the blimp is an important issue: it can be the blimp mission, it will be required to define trajectories servoed on the overflown environment, and will also be the basis upon air/ground cooperation scenarios can be achieved.

To study, develop and experimentally validate the work on these issues, we acquired in the end of 2001 a 15 m³ airship, and defined the necessary on-board equipment.

The first mentions of the development of unmanned autonomous blimps can be found in the literature of the late 80's, but it's only recently that various projects have reached effective achievements:

The Aurora project held at the Information Technology Institute of Campinas, Brazil, mainly devoted to flight control. Some informations can be found here, and various publications parreared in the main airship and robotics conferences.

Lotte at the University od Stuttgart, very interesting developments on the development of a solar airship. Model identification and flight control are also considered issues.