Design, fabrication, and testing of a maneuverable underwater vehicle with a hybrid propulsor

Rapidity and agility are equally important to unmanned underwater vehicles (UUVs). In this study we developed a UUV equipped with a hybrid propulsor which consists of a screw propeller and four bio-inspired flippers. The bionic flippers rely on their flapping motion to generate both thrust and lateral forces, and the screw propeller provides additional thrust for fast cruise. The maneuverability is greatly improved while the capability of sailing fast is maintained. For the typical sailing requests, the flapping motions of the flippers were designed meticulously, and a control algorithm based on central pattern generators (CPGs) was built to produce rhythmic locomotor signals considering the motion periodicity. Simultaneously, a feedback control method was merged to correct the deviation of the course. A compact concentric-shafts transmission mechanism was employed to overcome the inadequacy of the inside space, and the vehicle was built. Finally, the sailing and maneuvering performance were tested. It was demonstrated that, the UUV's overall sailing performance was enhanced significantly due to the combination of the flapping flippers and the screw propeller. The hybrid-propulsor vehicle is capable of sailing in multiplicate environments.