Experiments in the coordination of underwater manipulator and vehicle control

Abstract

Experiments using the OTTER vehicle conducted at the Monterey Bay Aquarium Research Institute (MBARI) have shown that dynamical interactions between a robotic arm and an underwater vehicle can be very significant due to the hydrodynamic forces acting on the arm as it moves through the water. Using a new, highly-accurate model of these hydrodynamic interaction forces, which was developed as part of this research, a coordinated arm/vehicle control strategy was implemented. Under this model-based approach, interaction forces acting on the vehicle due to arm motion were predicted and fed forward into the vehicle control system. Using this method, vehicle station-keeping capability was greatly enhanced. Tracking errors and settling times for the manipulator end point were reduced significantly.