Technical Approach

The main innovative aspect of this project is the possibility of taking measurements during volcanic eruptions and the development of a robotic system for the exploration of one of the most difficult environments on the surface of the Earth. Measurement activities and sampling near active eruptive vents are normally not possible because of the extremely dangerous operative conditions due to both the unpredictability of volcanic activity and the very harsh environmental conditions. Up to date only a few observations close to active vents have been reported. They are related to unusually safe conditions or unscrupulous persons that run strong risks and sometime suffer serious personal injuries. However, only gas and lava sampling close to eruptive vents has been reported, probably due to the difficulties to operate with complex instrumentation.

Close to active eruptive vents the measurement and sampling processes are  fundamental  in volcanology and progress has been mainly in three fields: magmatic gas geochemistry, physical modelling of magma degassing, and stability assessment of the craters and domes. Even if several volcanological and geophysical topics will benefit from these data, we highlight the main contribution of  the robot-aided fieldwork to the above mentioned topics.

Magmatic gas geochemistry: due to the rapid mixing between the gas released by the magma and atmosphere it is quite difficult to make accurate measurements of the quantity of some gas species produced by volcanoes that are abundant also in the atmosphere. In particular the CO₂ released during the eruption could contribute significantly to the global warming of the planet. Accurate measurement of this during the eruption of basaltic magma, in which it is more abundant, will help to better discriminate natural and human activity contributions of the CO₂ increase in the atmosphere.

Physical modelling of magma degassing: dynamics of the gas bubbles that rise up in the magma and disrupt at the surface drives all eruptions. Its modelling depend on the geophysical data collected close to the disrupting surface where the bubbles burst. This process is very frequent in active craters of the basaltic volcanoes where explosive activity is produced. Unfortunately it observation and measurement is often prevented by the funnel shaped geometry of the volcanic vents, so a very close approach with  specific instrumentation (stereo cameras, Doppler-radar, etc.)   is necessary to collect these data.

Stability assessment of the craters and domes: active volcanic crater and dome structures are subject to a rapid growth during an eruption and often collapse under their own weight and due to endogenous forces. Dome collapses produce very dangerous pyroclastic flows and surges. Crater collapses block the erupting vent and can produce large explosions due to gas overpressures inside. The measurement of the instability of craters and domes will be very useful to forecast dangerous eruptive phenomena, however due to the unpredictability of these collapses  fieldwork  is not possible without a robot.

In known, published literature, there is only one example of a robot specifically developed for volcano exploration, Dante II. Dante II is a frame walking robot designed at CMU (Carnegie Mellon University) Field Robotics Center (FRC) for Volcano explorations. In particular it was tested on Mt. Spurr volcano (Alaska) in July 1994.

There are many other examples of robots that have been designed for planetary exploration and that have been tested on volcanic sites. In fact there are many similarities between volcanic terrain and many planetary sites. It is important to observe that  not one of these robots has been totally developed in an EC country. As important examples that we can cite is the Marsokhod Planetary Rover (designed from the Russian Academy of Science's Institute for Space Research Institute (IKI)),  Sojourner(JPL), Rocky7 (JPL).

Details concerning these and other innovative walking machines can be found in the Walking machine catalogue set up by Dr. Berns of  FZI (Germany).

The lessons learnt from these previous machines and the advances made in robotic walking will be directly applied to the new ROBOVOLC machine to be developed. The major innovations will be in the mechanical structure and materials (lightweight, dust proof, heat and impact resistant), locomotion systems (intelligent control, robust traction for the harsh and unstructured environment), guidance (environmental mapping, intelligent path-planning, autonomous decision making) and sensors (integration of a variety of sensors for robust localisation and environment reconstruction, an effective user interface).

 The development of the subsystems will follow a modular plan which is been promoted from the EC Thematic Network for this area of technology CLAWAR. The aim of developing such modularity in the robotics area is to promote rapid prototyping, reduction in development costs and widespread  adoption of the solutions developed. The modularity that is being developed addresses several aspects ranging from mechanical, electrical, electronic, communications and functionality viewpoints. The concept of plug-and-play units that can "broadcast" their presence within a distributed computing hierarchy is likely to be employed, so that operational strategies can be modified to maintain optimal performance. This is the basis for the development of the modules that the CLAWAR project is promoting. For example the walking strategy of a six legged machine may need to be modified if one of the legs fails (which is likely in the hostile environment being addressed) and the failure is broadcast to the rest of the system for remedial actions to be initiated. The aim of developing a modular approach is so that a set of "lego type blocks" can be constructed and put together to meet a range of specific requirements for a range of applications. In this way the ROBOVOLC machine developed as part of this project could have several spin off uses where the  modules can be used in other applications. For example the modules could be utilised in other machines developed for unstructured environments (earthquakes, demining, fire-fighting, and other dangerous or inaccessible situations).

In this project it is not the intention to develop new standards, but to utilise the new methods of modularity that have been promoted in this area by others. In particular the data collected by the measurement system will utilise the format adopted by European volcanologists (EMEWS project, ENV4980728 :   IPGP (Partner 3) is co-ordinator for this project and Partner 2 is also involved) so that there is easy transfer of information between the different systems being developed for use in predicting and observing volcanic activity.

Furthermore, the integration of the modular subsystems developed on the project will in itself represent a  major advance in the state of the art in this research area.

In particular the mechanical structure and the materials to be adopted should ensure that the robot is resistant to rainfall that contains erupted fine particulates. It will also need to be fast and agile so that the problems encountered with the Dante II do not arise. The locomotion system adopted should allow the robot to move easily over volcanic terrain. Since the volcanic environment is very harsh, innovative solutions are to be explored across the range of  wheeled, legged, climbing, tracked, or hybrid robotic typologies.

The measurement system should permit an accurate reconstruction of the surrounding environment both for autonomous or tele-operated operations.New navigation and path planning algorithms will be developed to investigate the capability of performing a given task autonomously.

A suitable user interface comprising a reconstruction of the environment will be designed to allow a non-expert operator to manoeuvre the robot or the measurement system  to program such functions.

A real-time webcam filming the inside of a volcano  will be posted on the web during the testing of the Robovolc machine. Several surveillance cameras actually operate on volcanoes to film their eruptive activity. Some of these are posted on the world wide web. In particular the International Institute of Volcanology (Partner 2 CNR-IIV) has set up three volcano cameras in 1993 and have posted volcano images in real-time on the web since 1995. This  new webcam filming the inside of a volcano will represent a major scoop because such activities have never been shown displaying such  strong and unusual conditions and it will be useful to demonstrate the feasibility of the Robovolc project to people all around the world.

The integration of all these subsystems in the trials of the robot will be performed directly on active European volcanoes. To date, a robot for volcano exploration and measurement has never been implemented in an EC country.