The research and development work carried out at the Dynamical Systems and Ocean Robotics Laboratory (DSORlab) of ISR aims at contributing to furthering the knowledge in the general area of dynamical system theory and applying it to the control and operation of robotic ocean vehicles.
Over the past the few years, research work has been focused on the study of advanced linear and nonlinear system theory and their use in the development of new methods for autonomous vehicle navigation, guidance, and control as well as combined plant/controller optimization. Considerable effort has also been placed on the study of hybrid systems for mission control of robotic vehicles, to enable the analysis and design of entities that capture the interplay between time-driven and event-driven systems.
Development work has led to the construction of the robotic ocean vehicles DELFIM (an autonomous surface Catamaran), INFANTE (an autonomous underwater robot) and CARAVELA (an autonomous oceanographic vessel) to field test new theoretical concepts in the abovementioned areas and pave the way for a fruitful symbiosis between marine science and marine technology. This follows the successful development of MARIUS, the first civilian European autonomous underwater vehicle for coastal oceanography in a project coordinated by the ISR/IST, under the auspices of the Commission of the European Communities. The DSORL has also played an active role in the design and implementation of the navigation, guidance, control, and mission control systems of SIRENE, an underwater shuttle for the automatic deployment of benthic laboratories, in the scope of a European project coordinated by IFREMER, France.
The main theoretical lines of research that are being pursued at the DSORL include the study of new techniques for trajectory tracking and path following, control of underwater vehicles under wave disturbances using H2/Hinfinity control theory, and combined plant / controller optimization using the theory of linear matrix inequalities and convex optimization theory. Work is also being done on the control of nonlinear systems using Lyapunov-based techniques, “back-stepping”, and switched hybrid control. New methods for navigation system design are being developed using the theory of multi-rate, polytopic, and linear parametrically varying systems.
At the mission control level, work has been focused on the development of software and hardware tools for mission programming and mission execution of autonomous vehicles, including cooperative control of surface and underwater vehicles. A specially designed Petri-net based software application named CORAL was developed to enable automatic generation of target code for vehicle mission execution. The complete system has been successfully tested on the prototype vehicles MARIUS and PHOENIX (an autonomous underwater vehicle that is property of the US Naval Postgraduate School). An important milestone was achieved when CORAL was used to control the Italian ROMEO ROV at distance, over the Internet, in early 1999. This was done in collaboration with the Istituto Automazione Navale, Genova, Italy. Work is also being pursued on the development of hardware architectures for distributed real-time control of ocean robotic vehicles.