The ENDURANCE AUV is a unique vehicle designed to generate high resolution maps of underwater environments. It can actively control motion in all 4 degrees of freedom (X,Y,Z, and yaw; pitch and roll are damped to provide a stable platform for pointing instruments).
The mapping system consists of an array of 56 obstacle avoidance sonar elements arranged in the shape of three great circles, a configuration designed to facilitate SLAM since it allows the vehicle to observe previously mapped regions at all times. In addition the vehicle has a high resolution multi- beam sonar capable of generating very precise (0.25 cm) maps.A combination of inertial, Doppler, and depth sensors is used to provide position estimates the dead reckoning drift is 0.04% of distance traveled (50% CEP). Data from a USBL is used to eliminate drift errors and serve as a backup pose estimation system.
Onboard Power and Propulsion
ENDURANCE is designed to be fully redundant. The vehicle has two banks of thrusters, each consisting of a set of three orthogonal thrusters (one for each direction in space). The system is fully controllable even when only one bank is in operation. Similarly, the system contains two independent lithium ion batteries and is capable of operating entirely off of one battery if necessary.
The ENDURANCE vehicles navigation library is comprised of algorithms that push the current state of the art for 3D robotic exploration. The 3D SLAM module is used to localize the vehicle in feature rich environments where dead reckoning or USBL localization is not an option. The wall following module allows the vehicle to track and map an uneven surface at a fixed standoff distance. The reactive obstacle avoidance and path planning modules allow the vehicle to move around cluttered environments.