Rendezvous of Networked Autonomous Underwater Vehicles in 3D Space

Autonomous underwater vehicles (AUVs) are widely used in 3D marine environments for oceanographic inquiry. Once AUVs have finished their tasks, they are often required to return to a common destination to dock or exchange information. To achieve the rendezvous of a group of AUVs, a distributed controller is designed by taking into account the vehicle 3D nonholonomic constraints and the entire group network connectivity. Each AUV considered in this study has 6 degrees of freedom (DOF) and can move longitudinally freely along with roll, pitch and yaw rates but not laterally and vertically as imposed by vehicle nonholonomic kinematics. The group of AUVs is networked based on a directed spanning graph to enable group-level communication and collaboration capabilities. It is critical that the network of the group always be preserved during all AUV motions to avoid communication and collaboration failures. The designed distributed controller is based on a dipolar navigation function that generates potential forces to align the AUV configurations with the common destination and to enable the group vehicle-to-vehicle distances to be maintained. This ultimately results in the group network to be continually connected. Simulation results are presented to demonstrate the ability and effectiveness of the proposed distributed controller to steer a group of AUVs to achieve rendezvous.