The Phoenix Autonomous Underwater Vehicle

The Phoenix autonomous underwater collaboration with other scientists interested in either vehicle (AUV) is a robot for student research in robot or virtual world. Repeated validation of shallow-water sensing and control (Figure 1). Phoenix simulation extensions through real-world testing is neutrally buoyant at 387 pounds (176 kg) with a hull remains essential. Details are provided on process length of 7.2 feet (2.2 m). Multiple propellers, coordination, reactive behaviors, navigation, real-time thrusters, plane surfaces and sonars make this robot sonar classification, path replanning around detected highly controllable. The underwater environment obstacles, networking, sonar and hydrodynamics provides numerous difficulties for robot builders: modeling, and distributable computer graphics submerged hydrodynamics characteristics are complex rendering. Finally in-water experimental results are and coupled in six spatial degrees of freedom, sonar is presented and evaluated. problematic, visual ranges are short and power endurance is limited. Numerous Phoenix contributions include artificial intelligence (AI) implementations for multisensor underwater navigation and a working three-layer software architecture for control. Specifically we have implemented the execution, tactical and strategic levels of the Rational Behavior Model (RBM) robot architecture. These three layers correspond to hard-real-time reactive control, soft-real-time sensor-based interaction, and long-term planning respectively. Operational software functionality is patterned after jobs performed by crew members on naval ships. Results from simple missions are now available. In general, a critical bottleneck exists in AUV design and development. It is tremendously difficult to observe, communicate with and test underwater robots because they operate in a remote and hazardous environment where physical dynamics and sensing modalities are counterintuitive. Simulation-based design using an underwater virtual world has been a crucial advantage permitting rapid development of disparate software and hardware modules. A second architecture for an underwater virtual world is also presented which can comprehensively model all necessary functional characteristics of the real world in real time. This virtual world is designed from the perspective of the robot, enabling realistic AUV evaluation and testing in the laboratory. 3D real-time graphics are our window into the virtual world, enabling multiple observers to visualize complex This work describes software architectures for an interactions. autonomous underwater robot and for a corresponding Networking considerations are crucial within and underwater virtual world, emphasizing the importance outside the robot. A networked architecture enables of 3D real-time visualization in all aspects of the multiple robot processes and multiple world design process. Recent work using the Phoenix AUV components to operate collectively in real time. is notable for the successful implementation and Networking also permits world-wide observation and integration of numerous software modules within