Experiments in the coordination of underwater manipulator and vehicle control

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