Real-time control

This thesis presents a systematic method for the design and modeling of flexible manufacturing systems, using object-oriented concepts and Petri nets. In the method proposed, we first define the system components in terms of an object model consisting of hierarchical sets of classes and operations. Secondly, we model the dynamic aspects of the system using statecharts, including exceptions. As a third step, we derive Petri nets from those statecharts to realize the concurrency present in the system. Finally we develop a hierarchy of controllers, corresponding to the layers of the object model, for the independent components of the system based on the Petri nets obtained in the previous step.

Any Autonomous Underwater Vehicle (AUV) software system is expected to be dynamic due to changes in mission goals, addition of new hardware, implementation of new algorithms, etc. Thus, for a successful AUV program, it is important to have a carefully and properly designed software architecture that is flexible enough to accommodate future changes. The AUV program in the Ocean Engineering Department of Florida Atlantic University has undergone significant development over the past one and a half years to achieve a flexible software system. This flexible architecture should also help in performing diverse kinds of AUV missions with minimal reconfiguration. The focus of this thesis work is to perform m evaluation of the past and present software systems used in our AUVs, and to describe the implementation details that were necessary for the migration of the past software system to a newer, more flexible and powerful software architecture. Another purpose of the thesis is also to describe the design philosophy behind the new architecture and its impact on the AUV program.