Design, Prototyping, and Experimentation of a Dual Helical Drive Vehicle for Underwater Exploration

This paper presents the development of a novel underwater screw-propelled vehicle prototype capable of operating both on the surface of the water and underwater. The locomotion of the prototype is controlled by the thrust and buoyancy generated by two helical drives or Archimedes' screws. The thrust generated by the drive depends on its rotational speed while the buoyancy depends on the amount of water in the central cylinder or ballast. Experimentation of the prototype's operation was conducted in a 3.35m-deep diving well at North Carolina State University. Real-time data acquisition and controls were performed through a tethered connection to the vehicle, and video post-processing was used for position estimation. Results from the vehicle's locomotion are presented as it demonstrates a variety of maneuvers including moving along the surface, controlling and maintaining a desired operating depth, and travelling while fully submerged. The experimental data acquired can now be applied towards dynamic model validation in efforts to develop an autonomous underwater screw-propelled vehicle.