DESIGN AND DEVELOPMENT OF COMMAND AND CONTROL SYSTEM FOR AUTONOMOUS UNDERWATER VEHICLES By TAN YEW TECK SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ENGINEERING

Over the last decades, the problem of building Autonomous Underwater Vehicles (AUVs) for missions in partially unknown underwater environment continue to challenge researchers. Although the AUV technology has matured and commercial systems have appeared in the market, a generic yet robust AUV command and control system still remains a key research focus. This thesis presents a novel command and control system architecture for modular AUVs. Particular focus on this thesis is the design and development of a generic control and software architecture for a single modular AUV while allowing natural extensions to multi-vehicle scenarios. The proposed command and control (C2) system has a hybrid, modular hierarchical control architecture. It adopts deliberative top-down approach in mission level decision making and task planning while utilizing reactive bottom-up approach for navigational control, obstacle avoidance and vehicle fault detection. The structure provides vehicle developers with an explicit view of the clearly defined control responsibilities at different level of control hierarchy. The underlying software architecture of the C2 system adopts component and modular based design principle. Every C2 component has its local data structure and implements its own logic without interfering with other components. Such a design has several advantages for component construction and maintainability. All the components have a uniform software interface to facilitate inter-component communication within the AUV via Remote Procedural Call (RPC). This allows computational load distribution by deploying C2 components onto different processors in the AUV. The component based approach exhibits robustness and adaptability as different components can be configured or exchanged depending on the requirement of mission. The resultant C2 system has been programmed and tested on a 3D System-In-TheLoop simulator. It is also operational on a prototype AUV known as STARFISH built by the Acoustic Research Laboratory (ARL) of the National University of Singapore