Flexible and Safe Control of Mobile Surface Systems

The primary innovation of this work is a novel Petri net based approach for safe and flexible control of highly capable mobile surface systems, such as long-duration science rovers, crew surface systems, multi-robot and human-robot teams. The traditional approach of time-based sequence of commands will not be adequate for commanding and coordinating those surface systems because it does not support concurrent tasks and team coordination. Those surface systems will best be supported by a state-based control architecture that explicitly models the states and their interactions. Petri net is a mature and flexible formalism for representing such a state-based control architecture. This research will develop novel Petri net based techniques to enable 1) explicit modeling and control of concurrent tasks, team coordination, and mode switching, and 2) dynamic reconfiguration of a Petri net during its execution to support onboard planning and human/robot interactions. The result of the proposed effort will be a Petri net based executive that can be integrated into a robot planning and control system for flexible and safe control of mobile surface systems. In addition, a graphical tool will also be developed to enable operators to visualize, edit, and analyze the Petri nets.